# Seismic monitoring of strength in stabilized foundations by P-wave reflection and downhole geophysical logging for drill borehole core

Per Lindh, Polina Lemenkova

► To cite this version:

Per Lindh, Polina Lemenkova. Seismic monitoring of strength in stabilized foundations by P-wave reflection and downhole geophysical logging for drill borehole core. Journal of the Mechanical Behavior of Materials, 2023, 32 (1), pp.20220290. 10.1515/jmbm-2022-0290. hal-04128887

HAL Id: hal-04128887

https://hal.science/hal-04128887

Submitted on 14 Jun 2023

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

Research Article

Per Lindh and Polina Lemenkova*

# Seismic monitoring of strength in stabilized foundations by P-wave reflection and downhole geophysical logging for drill borehole core

https://doi.org/10.1515/jmbm-2022-0290

received August 25, 2022; accepted May 12, 2023

**Abstract:** Evaluating the subground properties during the initial stage of a construction of building is important in order to estimate the suitability of soil quality to the technical requirements of bearing capacity, resistance to stress, and strength. This study presented the evaluation of the geotechnical properties of soil intended for the construction of Max IV facility of Lund University, performed in fieldwork and laboratory. The *in situ* methods included drilling boreholes, core sampling and assessment, crosshole measurements, and borehole logging. The laboratory-based measurements were performed at Swedish Geotechnical Institute and combined seismic measurements of drill cores, determination of the uniaxial compressive strength (UCS), and examination of material property: sieve analysis and natural moisture content. UCS was evaluated with regard to velocities of elastic P-waves. The synchronous light test by X-ray diffraction was performed for qualitative analysis of mineral composition of samples. The study applied integrated approach of the diverse geophysical methods to solve practical tasks on the evaluation of foundation strength and geotechnical parameters. This study demonstrated the benefits of integrated seismic and geophysical methods applied to soil exploration in civil engineering for testing quality of foundation materials.

**Keywords:** seismicity, elastic wave, X-ray diffraction

## 1 Introduction

Geophysical methods offer an effective tool for the evaluation of physicochemical and mechanical parameters of soil in civil engineering. Information regarding the lithological structure and mineral content and geochemical and geological properties of soil can be extracted from the core drilling and geophysical borehole logs [1,2]. In recent years, research shows that geophysical methods of data processing are certainly required in cases when non-destructive methods are advisable. For instance, parameters of acoustic velocities of seismic waves penetrated through the soil specimens can be used as a dataset for the estimation of soil strength in a laboratory using the reflectivity of P-waves [3,4]. Furthermore, data processing aimed to investigate the strength, elasticity, and mineral properties of soil specimens, which can be performed using the acoustic imaging and seismic testing by measuring the velocities of P- and S-waves [5–7] as well as X-ray-diffraction (XRD) for testing the mineral content of soil [8].

Evaluation of strength properties of soil is an essential requirement for construction works for safety and stability of buildings. Prior to the constructions and engineering works, clayey soil should be reinforced using binders. In the environmental and climate conditions of Sweden, weak expansive clayey soil is subject to seasonal swelling and shrinking. This can lead to a serious damage of civil engineering objects, roads, and infrastructure. To avoid this, clayey soil should be stabilized using binders prior to its use in engineering works. Stabilization may also include the environmental aspects, such as cleaning the material from chemicals, pesticides [9,10], and toxic hazardous materials [11].

Stabilization of soil by binders results in the increased strength, which can be evaluated using the uniaxial compressive strength (UCS) test. Binders usually include materials such as cement [12,13], lime [14,15], slag [16], and cementitious materials [17] in various proportions and

<figure><img src="image_3.png" /></figure>

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

<footnote>* Corresponding author: Polina Lemenkova, École polytechnique de Bruxelles (Brussels Faculty of Engineering), Laboratory of Image Synthesis and Analysis (LISA), Université Libre de Bruxelles (ULB), Campus de Solbosch - CP 165/57, Av. F. D. Roosevelt 50, B-1050 Brussels, Belgium, e-mail: polina.lemenkova@ulb.be</footnote>

<footnote>Per Lindh: Department of Investments, Technology and Environment, Swedish Transport Administration, Neptunigatan 52, Box 366, SE-201-23, Malmö, Sweden; Department of Building and Environmental Technology, Division of Building Materials, Lund University, Lunds Tekniska Högskola LTH (Faculty of Engineering), Box 118, SE-221-00, Lund, Sweden, e-mail: per.lindh@byggtek.lth.se</footnote>
content [18]. Additional methods of evaluation of soil quality and parameters include the geophysical data processing and interpretation of the borehole logs [19–21]. Advances in the field of applied geophysics and data analysis made an important application become real: evaluating the soil characteristics through quantitative estimation of its parameters using the non-destructive geophysical methods. Such approaches include, for instance, the inverse geophysical methods that are based on the correlation of density and porosity of core with the response from the elastic seismic waves. The evaluation of these data can be performed using an integrated approach of interpretation of the crosshole measurements with acoustic testing of the core specimens. The aim of such applications is to evaluate the soil strength using measured seismic velocities of P-waves of the drill core.

Many civil engineering tasks can benefit from the use of applied geophysical methods. For instance, the interpretation of borehole logging enables us to obtain information on structural characteristics and mineral composition of soil, which can be determined from data analysis. The borehole logging presents an effective tool for geotechnical exploration for ground measurements inside the boreholes, widely used for soil analysis and reported in a variety of studies [22–25]. Probe sensors of the borehole logging system measure the physical properties of the ground, such as density, porosity, magnetic and radioactivity properties, electrical resistivity, and seismic velocity [26]. These data are useful for the evaluation of the soil quality and its suitability for the construction works.

XRD is another advanced method of evaluating the soil structure. This method is especially effective for the analysis of soil structure, including the evaluation of microfabrics, orientation of crystals, and identification of mineral content [27–29]. XRD applies the interference of the monochromatic X-rays in a crystalline specimen. The crystalline structure of soil diffracts the X-rays and responses to an X-ray diffractometer by a generated interference image. This pattern contains the information regarding the molecular structure of soil [30]. The benefit of the XRD for soil analysis is that it is a straightforward and functional method for qualitative identification of the soil structure, for quantifying the relative proportions of the minerals in a soil sample, and for detecting the soil evolution phases [31].

Optical images of the borehole wall of the drilling core in artificial colors are produced by the core scanner devices that allow us to record and visualize the wall sections of drilling cores. The acoustic televiewer is an essential feature of the borehole imaging based on the ultrasonic pulse-echo configuration [32]. Its approach

consists in plotting the borehole by the ultrasound, which is transmitted from the piezoelectric transducer in the borehole. The waves are reflected on the borehole by the mirror and measured as a log by the receiver, which records the amplitudes and the travel time of the signals [33]. These data record information regarding the fracture strike and the dip [34]. The acoustic data recorded by the borehole imaging system are used as an indication of the soil properties: characteristics, relation, and orientation of the lithologic and structural features of soil specimen [35].

New approaches in the acoustic borehole imaging are constantly developing with the aim to achieve the optimum performance of the device: to improve speed and precision of the data processing workflow [36,37], to increase the quality of imaging [38], to enhance the recognition of echoes and separate noise [39], and to adjust to the real-time borehole conditions [40]. In soil analysis, digital image and data processing provides an important source of information that can be used to control and improve the interpretation of geologic measurements obtained from borehole drilling [41–43].

The geologic impulse response from gamma (γ) rays in various beds of a borehole enables us to understand the geological nature and geophysical properties in complex sequences of the drilled layers [44]. Gamma-ray logging of the boreholes and spectrometer system have been reported for the determination of mineral compositions in a drill core [45] and concentrations of metals and radioactive elements (²³⁸U, ¹³³Ba, ²³²Th, and Mn) [46,47]. For instance, gamma-ray logs enable us to perform the granulometric estimation of the clay content in a soil sample, due to the high porosity and low resistivity of clay, which, together with its mineralogical composition (potassium), causes high gamma-ray emissivity [48,49]. The compensated gamma-gamma (γ-γ')-type density is a log-corrected for the negative effects of the gamma rays naturally occurring in radioactive elements (²³⁸U, ²³²Th), which is used for measuring the density of the borehole core layers [50,51].

The information regarding the geotechnical properties of soil intended to foundation constructions is normally acquired by the inspection of strength (UCS) [52–54]. Strength of soil also provides data on the quality of stabilization works. The compression machine for UCS test is usually applied to detect precise information of soil behavior in strain-stress conditions. More advanced geophysical methods include the non-destructive approaches using the evaluation of the velocity of seismic P-waves passed through soil specimens for analysis of strength.

The integration of the geophysical and engineering geological methods is important, since it enables us to use the benefits of both approaches and apply the diverse
tools for a complex assessment of soil properties prior to
construction works. For instance, the results on seismic
tests show the correlation between the UCS and P-wave
velocities, which is useful to control the quality of soil
stabilization, while borehole logging provides the infor-
mation regarding the local properties of the tested soil
specimens intended for a construction of foundation of
buildings.

This study presents the results of work aimed at
testing and improving the parameters of soil prepared
for the construction of foundation of the large building
facility. These include the geophysical borehole logging
for the core analysis, tests on soil stabilization, and geo-
physical investigations. The requirements for soil included
high strength, low sensitivity to vibrations, high bulk
density, and low porosity. This article is organized as
follows. The scope of this study and *in situ* condition of
a real project are presented in Section 2. Section 3 reports
the workflow of fieldwork and presents selected examples
of the core sampling and borehole logging. Section 4
defines the laboratory tests, including the UCS and seismic
tests. Section 5 presents the details of data processing
and describes the obtained results. Finally, the discussion
of the results is presented in Section 6, where the com-
ments on the performance of the methods are included.
Some remarks concerning the future works are provided in
Section 7.

## 2 Background and purpose

This article aims at testing soil strength in a planned con-
struction of building using applied geophysical methods

and engineering geological methods. The test area belongs
to the synchrotron radiation light laboratory Max IV (https://
www.maxiv.lu.se/) at Brunnshög in Lund, coordinated by
Lund University (Figure 1).

An essential parameter for the performance of Max IV
facility is related to the vibration characteristics because
soil foundation should be resisted to the high level of
vibrations. To evaluate the quality of foundation that
should meet the technical requirements regarding the
vibration, a series of simulations were carried out using
geophysical methods. The purpose of the project is to
improve the quality of the subsoil prepared for construc-
tion works and to test the results of stabilization through
the evaluation of the compressive strength characteristics
of the stabilized soil. The investigation of the properties
of the entire stabilized layer enables us to evaluate how
well the selected production model succeeded in creating
a homogeneous monolith of the stabilized soil material
using core drilling (Figure 2).

The drilling of the borehole core was performed to
select soil samples, stabilized and investigated by the down-
hole geophysical logging and seismic methods. This facility
has a unique basement foundation of the building con-
sisting of 160,000 m³ of clay moraine, which is required
to be stabilized and tested for strength.

The facility includes the independent experimental sta-
tions, which operate with a wide range of the experimental
techniques, including the crystallography, electron spectro-
scopy, nanolithography, and photo-nuclear experiments.
One of the prerequisites for achieving the stable performance
of the foundation of Max IV is to reduce the effects from
vibrations on soil. Therefore, this work consisted of redu-
cing the plant's sensitivity of foundation to vibrations
by increasing its rigidity, so that the components in

<figure><img src="image_7.png" /><figcaption>Figure 1: Fieldwork measurements at Max IV. Photo: Per Lindh.</figcaption></figure>
<figure><img src="image_8.png" /><figcaption>Figure 2: Core drilling. Photo: Per Lindh.</figcaption></figure>

accelerators and experimental stations could move in time. The foundation also has a certain reducing effect on vibrations from the internal and external sources. The required condition for vibration level is to be below 20–30 nm root means square displacement for frequency >5 Hz.

The research included the following objectives:

* to achieve the homogeneity of the subsoil prepared for basement construction,

* to evaluate the strength in the bonds in boundaries between the different layers of soil,

* to estimate the difference in density between the surface and deep-lying material through additional compaction provided by the overlying clay,

* to evaluate how the soil properties were improved in the stabilized specimens after curing, compared to the initial non-stabilized raw soil samples,

* to investigate the binding products on the stabilized material using *in situ* measurements in Max IV,

* to analyze the differences between the seismic results from the crosshole and seismic tests on the drill cores.

As a result of the performed works, the bearing capacity of soil was improved, which was proved by a series of tests, as presented and described in the following sections.

## 3 Fieldwork measurements

The measurements were performed in connection with the construction works aimed to improve the quality of soil through stabilization and to evaluate the results of soil stabilization through a series of seismic tests.

### 3.1 Core sampling

The field tests started with three core samples being drilled as cylindrical sections through the stabilized layer of soil down to the underlying naturally deposited clay moraine. The drilling was performed using the S Geobor, a wireline triple tube core barrel drilling system developed by Terracore [55]. The hole bit diameter is 146 mm; the core inner diameter is 102 mm (Figure 2). The drilling was carried out to a depth of 5 m, i.e., an under-drilling was of ca. 1 m below the stabilized layer. No core losses were reported in any of the three core drill holes. The examples of the drill cores are shown in Figures 3 and 4.

### 3.2 Stabilization

Stabilization of soil is a method that works best for improving its resistance toward the internal and external sources of vibration and load. Natural soil was stabilized beneath the two storage rings with the hydrated lime and

<figure><img src="image_9.png" /><figcaption>Figure 3: Drill core from the borehole no. 2, depth: between 4 and 5 m. The right part of the drill core consists of natural clay moraine, which is more plastic than the stabilized clay moraine. Photo Per Lindh.</figcaption></figure>
<figure><img src="image_10.png" /><figcaption>**Figure 4:** Drill core from the borehole no. 2, depth: between 1 and 2.5 m. The drill core shows homogeneous stabilization along the entire stretch. Photo: Per Lindh.</figcaption></figure>

ground granulated blast furnace slag (GGBFS) down to a depth of 4 m. The stabilization was carried out in layers of 3 m with an undercut in the underlying layer between 3 and 5 cm to ensure a homogeneous matrix. The continuous quality control was performed of each stabilized soil layer.

## 3.3 Crosshole measurements

The tests on the crosshole measurements were based on the three core samples collected from the ground surface down to the bottom of the stabilized layer (to 3.15 m). The specimens of the drill cores were mapped and photographed, after which selected samples were measured for P-wave velocity, compressive strength, density, and deformation. The specimens were tested at the diffraction beam tube BLI 711 at MAX-lab, Öle Römers väg, Lund. The crosshole measurements were performed with a new type of equipment, which has extended possibilities to measure shear wave and compression wave velocity in the material between the boreholes. The system consists of

a transmitter unit that generates shear or compression waves using two receiver units (geophones) (Figure 5).

The tests were performed in accordance with standard ASTM D4428/D4428M-14 [56]. The crosshole measurements show the achieved requirements for the soil quality in terms of velocities of horizontally traveling seismic waves in soil: primary compression wave (P-wave) and secondary shear wave (S-wave). Since stabilized soil was considered sufficiently strong, no reinforcement of the borehole walls was carried out except by a thin layer filled on top of the stabilized layer (Figure 6).

The design criterion was a minimum shear wave speed ($W_s$) of 900 m/s. Figure 7 shows a $W_s$ between 1,000 and 1,350 m/s (third curve from the left, red). The coefficient of lateral expansion is shown in Poisson's ratio (fifth curve left, red), with the lowest values (0.14) on the horizon at 1.20 m.

## 3.4 Borehole logging

The geophysical borehole logging has been performed using the technical tools of Ramboll Group AS. The examples of the detailed and precise analysis of the variations in physical parameters of core are presented in Figures 8–10. The logging has been carried out in the core boreholes with aim to derive lithological, structural, and rock mechanical information using geophysical methods. Geophysical borehole logs in Figures 8–10 also show the data for lithology analysis by a combined evaluation of the log responses and acoustic measurements.

The borehole logging system collected information on core using probes with embedded sensors. The data

<figure><img src="image_11.png" /><figcaption>**Figure 5:** Schematic sketch of crosshole measurements on Max IV.</figcaption></figure>
<figure><img src="image_12.png" /><figcaption>**Figure 6:** Crosshole measurements on Max IV. The seismic source was located in the borehole No. 1 on the far right of the image. Plastic pipes go down to the stabilized layer. Photo: Per Lindh.</figcaption></figure>

captured by the borehole logging system were transmitted to the computer using a logging cable. The system included a GPS and a depth encoder for the 3D coordinate capture. The results of the data processing include the borehole logging, which shows several plots of sensor outputs visualized in a horizontal coordinate system versus depth on the vertical axis, as shown in Figures 8–10.

Using borehole logging has important benefits for soil testing:

1) First, the reflected impulse of waves is directly related to the elastic and material properties of soil. This provides data on soil structure that can be received using both the direct measurements and indirect evaluation. The latter includes solving the inverse problem to estimate hidden parameters of soil from its related properties (e.g., porosity–density links).

2) Second, the acoustic testing device of the borehole logging is highly sensitive to the microstructure of the ground. Thus, the recording of logging can be used for recognition of the defects, detection of fractures and cracks in layers prepared for foundation construction.

The information is confined to a limited distance of 4.95 m tested around the boreholes drilled for Max IV. The structural analysis of core derived from borehole logging comprised data on the following parameters illustrated as vertical cross sections:

* depth from the ground level,

* natural γ rays,

* inclination from the vertical level,

* caliper probe 1-arm,

* compensated γ-γ density,

* porosity calculated from density,

* filtered radius image from the borehole wall (360 °),

* 3D caliper with borehole acoustical image,

* amplitude (360 °) of acoustical image of borehole wall,

* hardness computed from the acoustical median of the borehole wall.

The inclination shows the angle of vertical inclination formed between the geodetic point of measurement (located device) and the exact coordinate location of the core. The inclination phenomenon is owing to the physics of the Earth where the magnetic lines are not parallel to the surface. This results in a slightly titled position of the compass with inclined needle. This information is plotted on the graphs in azimuth °. The caliper probe 1-arm is a mechanical device used to measure the internal diameter of a borehole and to press a section of a probe against the side of the borehole for density logging.

The results of the analysis and characterization of soil structures are shown in Figures 8–10, which give the information regarding the natural gamma, caliper, acoustic televiewers, density, and porosity, which have been defined by a combined interpretation of the core images and acoustic images of the borehole. The hardness of the borehole wall was calculated using the results of the acoustic measurements. The results of the measurements of boreholes 2 and 3 show a variation in values at the depth of 2.5 m, while for borehole 2, it is also noted at 3.3 m. This variation in caliper results is also seen as a change in the hardness of the borehole wall.

During the examination of the drill cores, a thin layer (ca. 10 mm) of the not stabilized soil was detected, which well corresponds with the 2.5 m level of depth. The most likely reason for such variation is that the milling down in the underlying layer was too small, and therefore, this
<figure><img src="image_13.png" /><figcaption>Figure 7: Results from the crosshole measurements.</figcaption></figure>
<figure><img src="image_14.png" /><figcaption>Figure 8: Results from the borehole logging for borehole no. 1.</figcaption></figure>
<figure><img src="image_15.png" /><figcaption>Figure 9: Results from the borehole logging for borehole no. 2.</figcaption></figure>
<figure><img src="image_16.png" /><figcaption>Figure 10: Results from the borehole logging for borehole no. 3.</figcaption></figure>
layer has a lower strength. This difference in strength is not visible in other three boreholes and hence probably has a small extent for a selected borehole. The difference in soil strength does not affect the function of the foundation at the frequencies where the construction is sensitive to vibrations since these wavelengths are much longer (bigger) than this layer.

# 4 Laboratory tests

Laboratory investigations were performed in the Swedish Geotechnical Institute (SGI) and included (i) soil analysis (grain distribution and natural water content), (ii) seismic measurements, and (iii) UCS strength tests of the drill cores (Figure 11). These investigations were based on the three core samples that were carried out from the ground surface down to the bottom of the stabilized layer. The drill cores were mapped and photographed, after which the samples were selected for further determination of the P-wave velocity, compressive strength, and density. Furthermore, the material samples were tested at the diffraction beam tube BLI 711 at MAX-lab, Öle Römers väg, and Lund.

## 4.1 Compressive strength of drill cores

The soil parameters were improved through stabilization, which was performed using binders adjusted to the specific properties of soil: GGBFS and CaO, as also tested in previous studies showing the experiments on various

binder combinations on the results of soil properties [57,58]. Upon stabilization, the compressive strength of soil was evaluated. To ensure a good performance of foundation planned to be constructed on the given soil, the advanced geophysical methods were applied. These included drilling, core sampling and assessment, crosshole measurements, and borehole logging for testing soil. These data were then processed in the laboratory of SGI. The latter included seismic tests of drill cores, UCS, and examination of material property of soil through sieve analysis for grain distribution and natural moisture content.

UCS was tested according to the standards of the deformation controlling test developed by materials test systems (MTS) (Figure 11). The deformation rate was set constant to 2 mm/min, as tested specimens had a diameter of ca. 100 mm and a height of ca. 200 mm. Figure 11 shows a photo of the mechanical press MTS used for testing the UCS of the specimen collected in the bore 3:3 at depth: 2.95–3.15 m. The samples were compressed in a 500 kN. The 1% per minute was in the axial direction.

Since stabilized soil hardens differently depending on the stress level, this process could not be controlled in the *in situ* measurements, which showed a much slower curing process. The difference in hardening of soil in the laboratory and the *in situ* conditions can be partly explained by the difference in the temperature between the outdoor air conditions and the field setting. However, the differences in the overlay pressure might also add their impact, which could contribute to the strength development for the specimens collected in field. In fact, the test specimens were not stored with a successively increased ambient pressure as in the real design, which might have the impact on the results of soil hardening.

Other parameters aimed at the evaluation of the stiffness of soil that is being assessed using Young's modulus (E) and the shear modulus G. The Young's modulus evaluates the elastic properties of soil in tension or compression as a ratio between the tensile or compressive stress and the axial strain. In turn, the rigidity evaluates the shear stress of soil and is denoted by the shear modulus G, which depends on the degree of distortion of basement during deformation that results in shear stress being changed to the shear strain. These parameters are improved during the process of stabilization and solidification of weak clayey soil.

## 4.2 Sieve analysis and moisture content

The deformation performance of soil as a response to stress is a complex and non-linear parameter, controlled by many factors. Mineralogy plays an essential role in

<figure><img src="image_17.png" /><figcaption>**Figure 11:** The mechanical press MTS used for UCS test. The axial resonant frequency – 4,516 Hz; flex mode resonant frequency – 2,902 Hz. Photo: Per Lindh.</figcaption></figure>
strength and stress-strain behavior of soil. It includes the porosity and ratio of voids that correlate with soil stiffness, plasticity and rheology that affect the mechanical properties of soil, and structure and fabric related to the interparticle contact in soil. Since inner properties of soil influence its response to stress and strain, the analysis of soil structure is a fundamental part of the construction.

The sieve analysis test was performed according to the standard ASTM D7928-21E1 [59] for particle size distribution of fine-grained clayey soils by sedimentation analysis using hydrometer. The sieve analysis determined quantitatively the distribution of particle sizes of the fine-grained portions of soil samples. The fine-grained fraction of a soil was detected and discriminated within a range of other particle sizes as percentage of fraction, and the gradation curve was drawn to measure the ratio of each size of grain that is contained within the tested soil specimens.

## 4.3 Seismic tests of the drill cores

Evaluating the correlations between the seismic response of the elastic waves and strength properties of the stabilized soil is a key approach in non-destructive measurements of civil engineering. Given soil specimens are of identical type, the task is to identify the level of the resonant frequency in the ultrasonic waves, such that the values of P-wave velocity correspond to the level of strength on each measured sample of soil specimen.

Since soil is used as a basis for the building, this sets up the prerequisites to achieve a high performance of the ground foundation: stability, strength, and reduced effects from the vibrations.

Seismic measurements were performed as a free-free resonant column measurements of the P-wave velocity. In this test, a cylindrical sample was placed atop of a soft foam layer to simulate free boundary environment. The vibrations of P-waves were generated by a small hammer on one end of the tested specimen and measured velocities by the accelerometer that was attached to its another end. The fundamental frequency of seismic waves was measured with a ceramic shear ICP® accelerometer. The vibrational response of the sample correlates with the inner properties of its structure and thus enables us to estimate the strength and small-strain moduli of soil.

This is possible due to the existing correlation between the P-wave velocities with strength of the porous material. Thus, the more dense and less porous the soil is, the higher is the velocity of propagation of the P-waves penetrating through the soil. Vice versa, the increasing porosity in soil results in the lower speed of P-waves. Such fundamental properties of the values of seismic velocity enable us to use them as a robust indicator of the engineering properties of soil and to evaluate such characteristics of soil as compressibility, permeability, elasticity, and cohesion. In turn, these parameters of soil are crucial factors for evaluating its suitability as a basement prior to building construction as a reliable data on soil quality and safety of future building.

<figure><img src="image_18.png" /><figcaption>**Figure 12:** Grain distribution of soil performed to select binders for stabilization aimed to strengthen the foundation on Max IV.</figcaption></figure>
Measurements of the flex mode in tested specimens were carried out since flex mode gives a higher determination of the shear wave velocity in soil sample as it is more affected by the boundary conditions of the specimens. Comparing longitudinal resonant frequency (P-waves) and bending resonant frequency (S-waves) was performed for a quality control regarding the requirements for soil resistance to cracks and inhomogeneities in a specimen. For tested soil specimens, the relationship between the P and S waves is shown in Figure 15.

# 5 Results

## 5.1 Sieve analysis and natural moisture water content

The results of the sieve analysis are presented in grain size distribution curve of the natural clay moraine, which varied in different samples of the selected specimens, as presented in Figure 12.

The plots of the grain distribution curve were used to analyze the type of soil, which was detected to be moraine clays. The clay content varied between 22% and 45% of the total soil weight. Therefore, the binder recipe for stabilization was selected according to this type of soil and consisted

of 50% quicklime (CaO) and 50% of GGBFS. This recipe of binders proved to be robust enough to handle the variations in grain distribution and effectively stabilize clayey soil.

Natural moisture content was tested in order to obtain the information regarding the soil properties (Figure 13), to select a proper binder for stabilization and find an optimal recipe to handle the variations in a clay content. The natural moisture (water) content ($W_N$) of soil specimens varied between 11% and 23% with an average value of ca. 18% (Figure 13). The experiments on the variations in moisture (water) content within soil specimens were performed by adding extra water and evaluating the compactness of soil using the moisture condition value (MCV) test. The MCV test was used for assessing and testing the suitability of soil based on specimens being compacted by the soil settlement. The aim of this test was to evaluate the parameters of soil specimens in relation to the upper limits of moisture content.

## 5.2 Correlation between the seismic wave velocity and compressive strength

The results of the soil stabilization have been assessed using seismic velocities of the elastic waves using free-free resonance method, similar to the existing studies [60] and reported in a series of plots illustrating the

<figure><img src="image_19.png" /><figcaption>**Figure 13:** Natural moisture water content ($W_N$) in the samples.</figcaption></figure>
correlation between the gain in the compressive strength of soil and the wave speed. Using seismic testing is an important approach as it focuses on the advanced, non-destructive and robust evaluation of strength parameters of soil compared to the UCS traditional methods. Complicated properties of fine-grained moraine soil collected in real *in situ* conditions require that precise approaches are used for the analysis of suitability of soil used as a basis for a constructed building with highly demanding requirements regarding resistivity toward vibrations, density, and stiffness.

The P-wave and S-wave velocity data were integrated for the drill cores for optimization of the strength analysis. Eight samples were tested for the analysis of UCS and measurement of P- and S-wave velocity. The requirement for test specimens was a P-wave velocity of at least 1,430 m/s, which was achieved during the performed series of the experiments. The analysis of the seismic velocities of the P-wave and S-waves as well as their reflectivity measured in the boreholes demonstrated to be the essential methods for the evaluation of the strength of soil prior to the construction works.

Figure 14 shows the P-wave velocity of the soil specimens stored at 20 °C which achieved the required value already after 500 h of soil curing. Seismic measurements were carried out both on the compacted specimens collected *in situ* in the field and on the surface in laboratory conditions. The resonance frequencies of the P-waves of the specimens were measured before the UCS tests in the laboratory, which demonstrated the overall increase in the velocity of waves passing through tested specimens with curing time. This well correlates with the results of similar studies that measure P-wave velocity in UCS tests

for the evaluation of gain in strength of soil specimens [57,61,62].

Since the selected adhesive has a slow-setting nature, only the initial curing phase was measured *in situ*. The curing process of soil specimens was performed on the laboratory-treated specimens that were stored in a workplace of the SGI. The comparison between the core sampling and crosshole measurements provided consistent results. The stabilized soil well meets the set-up requirements for a minimum of shear wave speed at least 900 m/s. Moreover, the study has shown that the performed series of works on soil analysis, treatment, and improvement produced a homogeneous monolith without any major deviations in material properties, which was accepted for engineering constructions. The results of the *in situ* measurements demonstrate a correlation between the P- and S-values (Figure 15).

The maximum compressive strength amounted to 2,430 kPa at a deformation of about 1.75%, as demonstrated in Figure 16.

The majority of the tested specimens were selected from a depth of 2 to 4 m. The reason for this was that the specimens should have a slenderness factor of 2, i.e., the ratio between the length and diameter must be 2. This value was defined for a better comparison between the values of seismic wave speed and gain in UCS. Since the top two meters of the cores were more cracked, the crack-free length was not 200 mm. The second reason was to perform a correlation between the P-wave velocity and UCS. The compressive strength of the samples varied between 1,800 and 4,400 kPa (Figure 17) which shows a good correlation between the compressive strength and the P-wave velocity (over 80%), i.e., the model explains 80% of the variation in the dataset.

<figure><img src="image_20.png" /><figcaption>**Figure 14:** P-wave (compression) velocity against the curing time for laboratory tested soil samples stored at 20 °C.</figcaption></figure>

<figure><img src="image_21.png" /><figcaption>**Figure 15:** P-wave versus S-wave velocity for drill cores.</figcaption></figure>
<figure><img src="image_22.png" /><figcaption>**Figure 16:** UCS vs deformation; sample bore 3:3, depth: 2.95–3.15 m.</figcaption></figure>

The compressive strength of the drill cores increases only insignificantly with depth, so the higher ambient pressure does not affect much the hardening process, as shown in the correlation between the UCS and P-wave velocity in Figure 18.

Thus, the data from the drill cores showed only a weak tendency in increase of the compressive strength with depth. This tendency might be very weak because it is only based on a sampling above the level of 2 m below the ground surface where samples did not show any correlation between the depth and strength (Figure 18). The analysis of the variation in dry density of soil at different depths did not show any differences. In all cases, the variation in density was within 100 kg/m³ (Figure 19).

In this test, the moraine clay specimens of core collected from the three different sites of ground surface down to the bottom of the stabilized layer (to 3.15 m)

<figure><img src="image_23.png" /><figcaption>**Figure 18:** Compressive strength as a function of depth.</figcaption></figure>

were evaluated. The soil specimens were tested to assess the correlations between the UCS and values of P-wave velocity using free-free resonant method obtained from the relevant experiments. The data were evaluated statistically, visualized, and plotted to interpret the degree of correlation between the UCS and velocity of seismic P-waves, and the variability in their values.

## 5.3 XRD test

The analytical method based on XRD test was performed to quantify the mineralogical composition of specimens. Theoretically, the mineral content in a crystalline sample can be determined using XRD both qualitatively [63–66] and quantitatively [67–69]. In case of the quantitative case, the XRD is applied on the reference minerals that

<figure><img src="image_24.png" /><figcaption>**Figure 17:** P-wave (compression) velocity as a function of UCS.</figcaption></figure>

<figure><img src="image_25.png" /><figcaption>**Figure 19:** Density as a function of depth.</figcaption></figure>
<figure><img src="image_26.png" /><figcaption>**Figure 20:** Dried sample A. Minerals: chlorite (C), ettringite (E), feldspar (F), gypsum (G), illite (I), kaolinite (K), metamivianite (M), smectite (S), and zeolite stilbite (Z).</figcaption></figure>

are known to be commonly present in a given type of soil [70]. In our case, none of the minerals has had a known, fixed proportion, which could be a function of the internal standard. The synchronous light test was performed for the qualitative analysis of the mineral soil composition. Sampling and analysis were performed for both natural wet and dried samples (Figures 20 and 21).

The measurements were carried out at the diffraction beam tube BLI 711 at MAX-lab, Öle Römers väg, Lund. The samples were measured at the high resolution of 0.997 Å wavelength from 4 to 40° 2θ angle. The measurements enabled us to analyze the qualitative composition of soil. The evaluation of the components of soil structure with regard to the content of minerals and organic matter was based on the qualitative X-ray analysis, i.e., without correct ratios. From the drill cores, samples were taken as one from a superficial layer and one from a deep layer. In total, four samples were examined. The most important minerals in these samples were identified via the search/match method. Using this method, the following minerals have been identified: chlorite (C), ettringite (E), feldspar (F), gypsum (G), illite (I), kaolinite (K), metamivianite (M), smectite (S), zeolite stilbite (Z), and amphibole (A)m (Figure 20 and 21).

The purpose of the XRD analysis was to identify the possible differences in the material composition of soil specimens collected in different boreholes. The samples were tested both for those with natural water content and for the oven-dried material. The pozzolanic reaction materials in the tested materials were not identified. This is probably due to the too small levels in relation to the high levels of clay minerals. Moreover, there were no differences between the top and bottom layers, which could be seen in the tested soil. This proves that soil was homogeneous over the tested area.

# 6 Discussion

As demonstrated in this article, the determination of deformation and compressive strength is possible using the estimated velocities of the elastic waves. This study has shown the advantages of the integrated use of the engineering geological techniques of borehole core sampling and geophysical seismic methods of data post-processing for geotechnical studies in industrial engineering. Measuring UCS and stiffness
<figure><img src="image_27.png" /><figcaption>**Figure 21:** Native sample B. Minerals: amphibole (A), chlorite (C), feldspar (F), gypsum (G), illite (I), kaolinite (K), metavivianite (M).</figcaption></figure>

of the compacted soil is necessary to ensure that it meets the requirements of the high bearing capacity and acceptable stiffness to the acting external loads during the exploitation of the building. A sophisticated method of XRD based on the analytical tests was performed to quantify the mineralogical composition of specimens, as in existing similar studies [71,72]. The soil analysis was exerted to alleviate the selection of binders and remove possible negative impact of the irrelevant binders and thus to optimize the workflow process of soil stabilization.

The results show an advanced and well-functioning approach combining geophysical methods of drilling, borehole drilling, acoustic measurements, seismic tests by P- and S-waves, soil analysis, and stabilization. The presented results meet the design requirements regarding soil quality intended for foundation construction. Stabilization by GGBFS and CaCO₃ has proven to be well suited for solidification of the fine-grained homogeneous soil. The stabilization enabled us to significantly reduce the concrete slab in the construction polygon with the same or better performance. In connection with the construction works, a continuous quality control of each stabilized layer was carried out to monitor the quality of soil.

A notable difference between our proposed method of soil testing with significant usage of geotechnical tools and most of the existing soil evaluation traditional laboratory approaches [73–75] is that it is build upon integrated scheme of methodology that incorporates the fundamental geophysical methods of the acoustic tests to solve engineering tasks on empirical evaluation of soil strength for testing geotechnical parameters of foundation for the Max IV facility of Lund University. The integrated method of geological borehole drilling presented in this article includes the geophysical measurements and acoustic tests using seismic waves used together in the workflow of the project. Such integration of methods has proven to perform well with regard to the soil treatment technology, construction industry, material technology, and economics, as also reported in similar studies for road base application using a combination of the approaches [76–79].

Thus, the geological, geophysical, and geotechnical approach methods that use different approaches to the target research object were combined, i.e., soil, yet overlap in background principles of data measurements and processing. In contrast to the existing studies on soil stabilization,
these methods were linked in a connected workflow that facilitated complex soil investigation in the project area. For the more detailed analysis of soil properties, the synchronous light test by the XRD was applied, which enabled the qualitative analysis of mineral composition of soil. Specifically, the specimens were first mined using the drilling of core samples as cylindrical specimens and processed data. The properties of soil samples were estimated through the analysis of the borehole logging and detected certain differences in the crosshole measurements based on the three core samples. The soil samples were tested using the traditional approach of grain distribution analysis and water content.

The method of XRD was adopted for mineral analysis of specimens based on the heterogeneous crystalline structure of soil. The UCS and seismic tests were integrated, which presented the two approaches, the traditional evaluation of soil, which is similar to the existing studies [80], and the non-destructive precise measurements that are applied in engineering works on soil improvement [81,82], for cross-correlation of the UCS and the elastic wave speed. The evaluation of the results has been performed using digital data processing, computing, visualization, and plotting for decision making regarding the soil suitability as a subsoil foundation able to safely resist the load from the load-bearing structures during the construction of Max IV facility of Lund University.

The results of this study showed that no significant differences between the superficial and deep-lying samples could be seen in the investigated matrix, despite some natural small variations in the basic material specimens. The demonstrated results from the performed works on this project show great possibilities to stabilize a fine-grained soil. Specifically, this work tested the stabilization of the clay moraine used as a basis for constructions with high requirements on sensitivity to vibrations, as well as high strength and stiffness.

## 7 Conclusion

Evaluating the soil properties during the subsoil construction cycle is essential for the assessment of soil quality and compliance with the technical requirements. This includes the evaluation of parameters of soil that indicate whether the proposed substructure or building foundation corresponds to the technical requirements of stability and safety in terms of bearing capacity and stiffness. The extensive experimental tests using the *in situ*

data collected from the boreholes were conducted with promising results of application of the proposed workflow for similar projects designed for the facilities with the advanced requirements for soil ground.

This article demonstrated the geotechnical exploration of soil with examples of application of geophysical methods.

Future applications of this study can adopt presented methods of geotechnical exploration of the soil ground intended for the construction of complex facilities. Similar works may also consider the described methods that were performed in fieldwork and laboratory. It is recommended to evaluate the results of the UCS using velocities of elastic P-waves, since these methods demonstrated to be effective and robust for control quality of strength of the stabilized soil. The integrated approach demonstrated in this study can be applied in further works using the benefits of the integrated seismic and geophysical methods in soil exploration studies. Specifically, such methods have shown to be useful in civil engineering for testing quality of soil materials.

The presented results validate the following conclusions: (i) it is beneficial to apply geophysical methodology and tools for civil engineering works due to the demonstrated robustness and precision of data processing cycle: data capture, data analysis, data evaluation, data visualization and plotting, data interpretation, and decision making; (ii) the capability of data interpretation based on the analysis of the multi-format and heterogeneous data received from geophysical and geological exploration sources is realistic and advantageous for civil engineering and real geotechnical projects.

**Acknowledgements:** We thank the anonymous reviewers for their valuable comments. The authors thank Ola Malmgren (Peab Anläggning AB) for project management and coordination, Brian Norsk Jensen, Dörthe Haase (Max IV Laboratory) for assistance with tests, Staffan Hansen (Polymer Technology, LTH) and Nils Rydén (Peab Grundteknik/LTH) for assistance with data interpretation, Roger Wisén (Ramböll), for assistance with interpretation of geophysical logging, and Per-Olof Rosenkvist (LTH) for the assistance with the UCS tests. We also thank the reference group consisting of Richard Nilsson (Skanska Sweden AB), Roger Wisén (Ramböll), Brian Norsk (Jensen MAX IV Laboratory), and Johan Blumfalk (Hercules Foundation).

**Funding information:** The project was financially supported by the Development Fund of the Swedish Construction Industry (Svenska Byggbranschens Utvecklingsfond, SBUF) as project 13152, the Nordic Community Builder
Peab, Swedish Geotechnical Institute (SGI), and Max IV Laboratory of Lund University, Sweden. The Division of Building Materials of Lund University provided the concrete cutter for sawing samples.

**Author contributions:** All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

**Conflict of interest:** The authors state no conflict of interest.

## References

[1] Maučec M, Hendriks PHGM, Limburg J, de Meijer RJ. Determination of correction factors for borehole natural gamma-ray measurements by Monte Carlo simulations. Nucl Instrum Methods Phys Res A Accel Spectrom Detect Assoc Equip. 2009;609(2):194-204.

[2] Jing J, Ke S, Li T, Wang T. Energy method of geophysical logging lithology based on K-means dynamic clustering analysis. Environ Technol Innovat. 2021;23:101534.

[3] Lindh P, Lemenkova P. Resonant frequency ultrasonic P-waves for evaluating uniaxial compressive strength of the stabilized Slag-cement sediments. Nordic Concrete Res. 2021;65:39-62.

[4] Lindh P, Lemenkova P. Seismic velocity of P-waves to evaluate strength of stabilized soil for Svenska Cellulosa Aktiebolaget Biorefinery Östrand AB, Timr. Bulletin Polish Academy Sci Technical Sci. 2022;70:1-9.

[5] Tang XM, Patterson DJ. Single-well S-wave imaging using multicomponent dipole acoustic-log data. Geophysics. 2009 Dec;74(6):WCA211-23.

[6] Tronicke J, Paasche H, Böniger U. Crosshole traveltime tomography using particle swarm optimization: a near-surface field example. Geophysics. 2012;77(1):R19-32.

[7] Hadden S, Pratt RG, Smithyman B. Anisotropic full-waveform inversion of crosshole seismic data: a vertical symmetry axis field data application. Geophysics. 2018 Nov;84(1):B15-B32.

[8] Wang Q, Wang W, He X, Zheng Q, Wang H, Wu Y, et al., Changes in soil properties, X-ray-mineral diffractions and infrared-functional groups in bulk soil and fractions following afforestation of farmland, Northeast China. Sci Rep. 2017;7:12829.

[9] Contessi S, Dalconi MC, Pollastri S, Calgaro L, Meneghini C, Ferrari G, et al. Cement-stabilized contaminated soil: Understanding Pb retention with XANES and Raman spectroscopy. Sci Total Environ. 2021;752:141826.

[10] Lindh P, Lemenkova P. Soil contamination from heavy metals and persistent organic pollutants (PAH, PCB and HCB) in the coastal area of Västernorrland, Sweden. Gospodarka Surowcami Mineralnymi - Mineral Resources Management. 2022;38:147-68.

[11] Lindh P, Lemenkova P. Geochemical tests to study the effects of cement ratio on potassium and TBT leaching and the pH of the marine sediments from the Kattegat Strait, Port of Gothenburg, Sweden. Baltica. 2022;35:47-59.

[12] Lindh P. Compaction- and strength properties of stabilised and unstabilised fine-grained tills. Lund, Sweden: Lund University; 2004.

[13] Horpibulsuk S, Rachan R, Chinkulkijniwat A, Raksachon Y, Suddeepong A. Analysis of strength development in cement-stabilized silty clay from microstructural considerations. Construction Building Materials. 2010;24(10):2011-21.

[14] Okyay US, Dias D. Use of lime and cement treated soils as pile supported load transfer platform. Eng Geol. 2010;114(1):34-44.

[15] Jauberthie R, Rendell F, Rangeard D, Molez L. Stabilisation of estuarine silt with lime and/or cement. Appl Clay Sci. 2010;50(3):395-400.

[16] Lindh P, Lemenkova P. Evaluation of different binder combinations of cement, slag and CKD for S/S treatment of TBT contaminated sediments. Acta Mech et Autom. 2021;15:236-48.

[17] Yoon IH, Moon DH, Kim KW, Lee KY, Lee JH, Kim MG. Mechanism for the stabilization/solidification of arsenic-contaminated soils with Portland cement and cement kiln dust. J Environ Manag. 2010;91(11):2322-8.

[18] Lindh P. Optimizing binder blends for shallow stabilisation of fine-grained soils. Proc Institut Civil Eng Ground Improv. 2001;5:23-34.

[19] Liu L, Shi Z, Tsoflias GP, Peng M, Wang Y. Detection of karst voids at pile foundation by full-waveform inversion of single borehole sonic data. Soil Dyn Earthq Eng. 2022;152:107048.

[20] Ryden N, Dahlen U, Lindh P, Jakobsson A. Impact non-linear reverberation spectroscopy applied to non-destructive testing of building materials. J Acoust Soc America. 2016;140:3327.

[21] Comina C, Mandrone G, Arato A, Chicco J, Duò E, Vacha D. Preliminary analyzes of an innovative soil improving system by sand/gravel injections-Geotechnical and geophysical characterization of a first test site. Eng Geol. 2021;293:106278.

[22] Kaleris VK, Ziogas AI. Estimating hydraulic conductivity profiles using Borehole resistivity logs. Proc Environ Sci. 2015;25:135-41. 7th Groundwater Symposium of the International Association for Hydro-Environment Engineering and Research (IAHR).

[23] Dias LO, Bom CR, Faria EL, Valentín MB, Correia MD, de Albuquerque MP, et al., Automatic detection of fractures and breakouts patterns in acoustic borehole image logs using fast-region convolutional neural networks. J Petroleum Sci Eng. 2020;191:107099.

[24] Yu Y, Huisman JA, Klotzsche A, Vereecken H, Weihermü ller L. Coupled full-waveform inversion of horizontal borehole ground penetrating radar data to estimate soil hydraulic parameters: a synthetic study. J Hydrol. 2022;610:127817.

[25] Yu Y, Weihermü ller L, Klotzsche A, Lärm L, Vereecken H, Huisman JA. Sequential and coupled inversion of horizontal borehole ground penetrating radar data to estimate soil hydraulic properties at the field scale. J Hydrol. 2021;596:126010.

[26] Killeen PG, Mwenifumbo CJ, Ford KL. 11.14 - tools and techniques: radiometric methods. In: Schubert G, editor. Treatise on Geophysics. 2nd ed. Oxford: Elsevier; 2015. p. 447-524.

[27] Denaix L, van Oort F, Pernes M, Jongmans AG. Transmission X-ray diffraction of undisturbed soil microfabrics obtained by microdrilling in thin sections. Clays Clay Minerals. 1999;47:637-46.

[28] Das R, Purakayastha TJ, Das D, Ahmed N, Kumar R, Walia SS, et al. Effect of chemical pre-treatment for identification of clay minerals in four soil orders by X-ray diffraction technique. Nat Acad Sci Lett. 2022;45:39-44.
[29] Righi D, Elsass F. Characterization of soil clay minerals: decomposition of X-Ray diffraction diagrams and high-resolution electron microscopy. Clays Clay Minerals. 1996;44:791-800.

[30] Alderton D. X-ray diffraction (XRD). In: Alderton D, Elias SA, editors. Encyclopedia of Geology. 2nd ed. Oxford: Academic Press; 2021. p. 520-31.

[31] Adams FC. X-ray absorption and diffraction | overview. In: Worsfold P, Poole C, Townshend A, Miró M, editors. Encyclopedia of analytical science. 3rd ed. Oxford: Academic Press; 2019. p. 391-403.

[32] Paillet FL, Barton C, Luthi S, Rambow F, Zemanek JR. Borehole imaging and its application in well logging-an overview. Borehole Imag Soc Professional Well Log Analysts, Inc. 1990;6001:3-23.

[33] Ronquillo Jarillo G, Markova I, Markov M. Acoustic reflection log in transversely isotropic formations. J Appl Geophys. 2018;148:1-7.

[34] SPWLA. Effects Of lithology on televiewer-log quality and fracture interpretation. All Days of SPWLA Annual Logging Symposium; 1985. SPWLA-1985-JJJ.

[35] Williams JH, Johnson CD. Acoustic and optical borehole-wall imaging for fractured-rock aquifer studies. J Appl Geophys. 2004;55(1):151-9.

[36] Schepers R. Development of a new acoustic borehole imaging tool. Scientif Drill. 1991;2(4):203-14.

[37] Deltombe JL, Schepers R. New developments in real-time processing of full waveform acoustic televiewer data. J Appl Geophys. 2004;55(1):161-72.

[38] Al-Sit W, Al-Nuaimy W, Marelli M, Al-Ataby A. Visual texture for automated characterization of geological features in borehole televiewer imagery. J Appl Geophys. 2015;119:139-46.

[39] Wedge D, Holden EJ, Dentith M, Spadaccini N. Fast and objective detection and analysis of structures in downhole images. J Appl Geophys. 2017;144:157-72.

[40] Jerram DA, Millett JM, Kück J, Thomas D, Planke S, Haskins E, et al. Understanding volcanic facies in the subsurface: a combined core, wireline logging and image log data set from the PTA2 and KMA1 boreholes, Big Island, Hawai'i. Scientif Drill. 2019;25:15-33. https://sd.copernicus.org/articles/25/15/2019/.

[41] Källén H, Heyden A, Lindh P. Estimation of grain size in asphalt samples using digital image analysis. In: Tescher AG, editor. Applications of digital image processing XXXVII. Vol. 9217. International Society for Optics and Photonics. SPIE; 2014. p. 292-300.

[42] Källén H, Heyden A, Åström K, Lindh P. Measuring and evaluating bitumen coverage of stones using two different digital image analysis methods. Measurement. 2016;84:56-67.

[43] Lindh P, Lemenkova P. Utilising Pareto efficiency and RSM to adjust binder content in clay stabilisation for Yttre Ringvägen, Malmö. Acta Polytech. 2023;63(2):140-57.

[44] Conaway JG, Killeen PG. Quantitative uranium determinations from gamma-ray logs by application of digital time series analysis. Geophysics. 1978;43(6):1204-21.

[45] Ajayi O, Torres-Verdin C, Preeg WE. Fast numerical simulation of logging-while-drilling gamma-ray spectroscopy measurements. Geophysics. 2015 July;80(5):D501-23.

[46] Løevborg L, Nyegaard P, Christiansen EM, Nielsen BL. Borehole logging for uranium by gamma-ray spectrometry. Geophysics. 1980;45(6):1077-90.

[47] Mikesell JL, Senftle FE, Lloyd TA, Tanner AB, Merritt CT, Force ER. Borehole field calibration and measurement of low-concentration manganese by decay gamma rays. Geophysics. 1986 Dec;51(12):2219-24.

[48] Bhuyan K, Passey QR. Clay estimation from Gr and Neutron-density porosity logs. In: SPWLA 35th Annual Logging Symposium, Tulsa, Oklahoma. All Days; 1994. p. 1-10. SPWLA-1994-DDD.

[49] Diiiaz-Curiel J, Miguel MJ, Biosca B, Arévalo-Lomas L. Gamma ray log to estimate clay content in the layers of water boreholes. J Appl Geophys. 2021;195:104481.

[50] Arnold DM, Company H. editors. Borehole compensated density logs corrected for naturally occurring gamma rays. Halliburton Company; 1985. OSTI ID: 5961810; Patent Nr.: US 4529877; Assignee: Halliburton. https://www.osti.gov/biblio/5961810.

[51] Givens WW, Corporation MO. editors. Gamma-gamma density logging method. Mobil Oil Corporation; 1979. Patent US 4180727. United States. OSTI ID: 5614551. https://www.osti.gov/biblio/5614551.

[52] Lindh P, Winter MG. Sample preparation effects on the compaction properties of Swedish fine-grained tills. Quarter J Eng Geol Hydrogeol. 2003;36:321-30.

[53] Lindh P, Lemenkova P. Hardening accelerators (X-Seed 100 BASF, PCC, LKD and SALT) as strength-enhancing admixture solutions for soil stabilization. Slovak J Civil Eng. 2023;31(1):10-21.

[54] Lindh P, Lemenkova P. Impact of strength-enhancing admixtures on stabilization of expansive soil by addition of alternative binders. Civil Environ Eng. 2022;18(2):726-35.

[55] EDT AB, EDT AB. editors. Terracore core drilling tools - product catalogue. Epiroc Drilling Tools AB; 2018. online. https://terraroctordrilling.com/wp-content/uploads/2020/03/Terraroc CoreDrillingTools_Product_catalogue.pdf.

[56] ASTM. Standard Test Methods for Crosshole Seismic Testing. vol. 04.08 of Book of Standards Volume, developed by Subcommittee: D18.09. American Society for Testing and Materials; 2016. ICS Code: 93.020. https://www.astm.org/d4428_d4428m-14.html.

[57] Lindh P, Lemenkova P. Shear bond and compressive strength of clay stabilised with lime/cement jet grouting and deep mixing: A case of Norvik, Nynäshamn. Nonlinear Eng. 2022;11:693-710.

[58] Xu Y. Unconfined compressive strength of municipal solid waste incineration bottom ashes. Geotech Geol Eng. 2019;37:1373-82.

[59] Swedish Institute for Standards (SIS). SIS, editor. Standard Test Method for Particle-Size Distribution (Gradation) of Fine-Grained Soils Using the Sedimentation (Hydrometer) Analysis. SIS; 2021. Standard ASTM D7928-21E1. online. https://www.sis.se/en/produkter/external-categories/construction-astm-vol-04/soil-and-rock-ii-d5877-latest-astm-vol-0409/astmd7928-21e1/.

[60] Ismail AIM, Ryden N. The Quality Control of Engineering Properties for Stabilizing Silty Nile Delta Clay Soil. Egypt. Geotech Geologic Eng. 2014;32:773-81.
[61] Aldaood A, Khalil A, Bouasker M, Al-Mukhtar M. Experimental study on the mechanical behavior of cemented soil reinforced with straw fiber. Geotech Geologic Eng. 2021;39:2985-3001.

[62] Azimian A. Application of statistical methods for predicting uniaxial compressive strength of limestone rocks using non-destructive tests. Acta Geotech. 2017;12:321-33.

[63] Nabih M, ElShinawi A. Qualitative analysis of clay minerals and swelling potential using gamma-ray spectrometry logs: a case study of the Bahariya Formation in the Western Desert, Egypt. Appl. Radiat Isot. 2020;166:109384.

[64] Wang Q, Hu Q, Ning X, Ilavsky J, Kuzmenko I, Tom T. Spatial heterogeneity analyzes of pore structure and mineral composition of Barnett Shale using X-ray scattering techniques. Marine Petroleum Geol. 2021;134:105354.

[65] Mürer FK, Madathiparambil AS, Tekseth KR, Di Michiel M, Cerasi P, Chattopadhyay B, et al. Orientational mapping of minerals in Pierre shale using X-ray diffraction tensor tomography. IUCrJ. 2021;8:m0800747.

[66] Paranthaman R, Moses JA, Anandharamakrishnan C. Development of a method for qualitative detection of lead chromate adulteration in turmeric powder using X-ray powder diffraction. Food Control. 2021;126:107992.

[67] Butler BM, Hillier S. powdR: an R package for quantitative mineralogy using full pattern summation of X-ray powder diffraction data. Comput Geosci. 2021;147:104662.

[68] Wang C, Gu C. X-Ray diffraction. In: Reference module in earth systems and environmental sciences. Amsterdam, Netherlands: Elsevier; 2022. p. 1-8.

[69] Butler BM, Palarea-Albaladejo J, Shepherd KD, Nyambura KM, Towett EK, Sila AM, et al. Mineral-nutrient relationships in African soils assessed using cluster analysis of X-ray powder diffraction patterns and compositional methods. Geoderma. 2020;375:114474.

[70] Nowak S, Lafon S, Caquineau S, Journet E, Laurent B. Quantitative study of the mineralogical composition of mineral dust aerosols by X-ray diffraction. Talanta. 2018;186:133-9.

[71] Pires LF, Brinatti AM, Prandel LV, daCostaSaab S. Mineralogical composition of hardsetting soils and its effect

on the radiation attenuation characteristics. J Soils Sediments. 2016;16:1059-68.

[72] Naik AS, Behera B, Shukla UK, Sahu HB, Singh PK, Mohanty D, et al. Mineralogical studies of Mahanadi basin coals based on FTIR, XRD and microscopy: a geological perspective. J Geol Soc India. 2021;97:1019-27.

[73] Barwar A, Chandrappa AK, Sahoo U. Laboratory investigations on stabilization of weak clay soil using rice husk ash and cement. Innovative Infrastructure Solutions. 2022;7:327.

[74] Sharma RK. Laboratory study on stabilization of clayey soil with cement kiln dust and fiber. Geotech Geol Eng. 2017;35:2291-302.

[75] Lindh P, Lemenkova P. Laboratory experiments on soil stabilization to enhance strength parameters for road pavement. Transport Telecommun J. 2023;24:73-82.

[76] Gupta A, Arora VK, Biswas S. Contaminated dredged soil stabilization using cement and bottom ash for use as highway subgrade fil. Geo-Eng. 2017;8:20.

[77] Lindh P, Lemenkova P. Effects of GGBS and fly ash in binders on soil stabilization for road construction. Romanian J Transp Infrastruct. 2022;11:1-13.

[78] Eberemu AO, Osinubi KJ, Ijimdiya TS, Sani JE. Cement Kiln Dust: Locust bean waste ash blend stabilization of tropical black clay for road construction. Geotech Geol Eng. 2019;37:3459-68.

[79] Lindh P, Lemenkova P. Geotechnical properties of soil stabilized with blended binders for sustainable road base applications. Construction Materials. 2023;3:110-26.

[80] Yilmaz Y, Eun J, Goren A. Grouting 2017. In: Evaluation of unconfined compressive strength for high plasticity clayey soil mixed with cement and dispersive agents. ASCE; 2017. p. 270-9.

[81] Staab DA, Edil TB, Alumbaugh DL. GeoSupport Conference 2004. In: Non-destructive evaluation of cement-mixed soil. ASCE; 2004. p. 838-49.

[82] Madhyannapu RS, Puppala AJ, Nazarian S, Yuan D. Quality assessment and quality control of deep soil mixing construction for stabilizing expansive subsoils. J Geotech Geoenviron Eng. 2010;136(1):119-28.