bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Self Organizing Maps to multi-temporal and multi-spectral satellite images: classification and change detection
Authors: Giacco Ferdinando  , Colella Stefania  , Pugliese Luca  , Scarpetta Silvia
Published: February 2025

In this paper we employ the Kohonen's Self Organizing Map (SOM) as a strategy for an unsupervised analysis of two IKONOS multispectral images of different dates. The main object is the development of an automatic multi-temporal analysis methodology of the land use modifications through change detection techniques using remotely sensed data. In order to obtain an accurate segmentation of changes we introduce as input for the network, in addition to spectral data, some texture measures, which give an essential contribution to the classification of changes in man-made structures. Furthermore we introduce a classical statistical method based on the image differencing and we evaluate the classification performances of the proposed approaches. We propose the results obtained with different combinations of the multi-temporal input data and compare them with prior knowledge of the scene analyzed.
A Pre-Filtering and Post-Filtering Approach to Blind Source Separation
Authors: Scarpiniti Michele  , Bunkheila Gabriele  , Parisi Raffaele  , Uncini Aurelio
Published: February 2025

In this paper a pre-filtering and a post-filtering approach to blind source separation in reverberant environment is presented. The preprocessing consists in the use of common acoustical poles that can simplify the recovering network, giving some a priori information on the environment. In particular the autoregressive part of a transfer function in a closed environment is common for all positions. After pre-filtering conventional BSS algorithm in frequency domain is applied to get estimates of original sources. In addition an adaptive noise canceler is used as post-filter in order to enhance the quality of the separation. Some experimental results demonstrate the effectiveness of the proposed approach.
Quadrupole polarizabilities of the rare-gas homonuclear diatoms and methane molecules
Authors: El-Kader M.S.A.
Published: February 2025

The contribution of the quadrupole polarizability C to the long-range polarizability of two interacting rare-gas atoms and methane molecules is specified by fitting the trace and anisotropy models to the intensity of the isotropic and anisotropic interaction-induced light scattering spectra. Good agreement with ab initio results in the literature is obtained and the first few even moments of these profiles are in excellent agreement with experiments.
Modulation of stimulated Brillouin scattering and stimulated temperature scattering spectral components by two-photon heating
Authors: Karpov V.B.  , Korobkin V.V.
Published: February 2025

The effects of linear (single-photon) and two-photon heating to the thin structures of the stokes and anti-stokes spectral components of stimulated Brillouin scattering (SBS) and stimulated temperature scattering (STS) are compared. The thin structures of the linear and two-photon STS-2 possess the same shapes. For the Fabry-Perot etalon based spectrum analyzer the linear and two-photon STS-2 components are experimentally indistinguishable not only from one another, but also from the STS-1 component. To reach the higher spectral resolution methods of heterodyning and intensity fluctuations correlation should be used. In contrast to a linear (single-photon) case for two-photon heating a stokes SBS component exhibits the spectral shift depending on the pump intensity. Emergence of the anti-stokes SBS component is possible when the pump intensity is sufficiently high so that the positive two-photon thermal gain may compensate the negative electrostrictive gain.
Assessment of the performace of the functional density theory to compute molecular polarizabilities using molecular polarization maps
Authors: Roset Lurdes  , Perez Juan J.
Published: February 2025

In the present report we analyze the performance of DFT to compute molecular polarizabilities through the analysis of molecular polarization potential that can be used as a tool to understand their spatial effects in the calculation of molecular polarizabilities. This is done in the present report through the results obtained for three reference molecules: hydrogen cyanide, formaldehyde and urea. Calculations were carried out at the density functional theory using the BLYP and B3LYP functionals. The results of the polarization maps reveal similar trends observed with the calculation of the different components of the polarizability tensor. However, the use of the maps permits to understand spatial effects specific for each level of calculation and each basis set.
An apparent critical point in binary mixtures of nitrotoluene with alkanes: Experimental and simulation study
Authors: Ratajczak Blazej  , Sliwinska-Bartkowiak Malgorzata  , Koziol Tomasz  , Coasne Benoit  , Gubbins Keith E.
Published: February 2025

We report an experimental and simulation study of binary mixtures of o- and m-nitrotoluene with decane and hexadecane. Mixtures of o-nitrotoluene with alkanes form a classical critical mixtures, but m-nitrotoluene / n – alkane mixtures show an apparent critical point, which lies in a metastable, experimentally inaccessible state, below the melting point, affecting physical and chemical properties of this systems in the stable liquid phase. The presence of the apparent critical point in this mixture has been experimentally observed by Nonlinear Dielectric Effect (NDE) measurements as an anomalous increase in the NDE values typical of critical concentrations. The phase diagram of this mixture shows evidence that the system freezes in the homogenous phase and its melting point is higher than its critical temperature [1–3]. For such a system, we performed Monte Carlo simulations aimed at analysing the kind of phase transitions observed, and the conditions of their occurrence in a nonpolar/dipolar mixture. We perform studies for classical critical systems of o-nitrotoluene with decane and hexadecane The enthalpy, configurational energy and radial distribution function have been estimated by the MC simulation method in the NPT system. Immiscibility conditions according to Schoen and Hoheisel [4] approach are also discussed.
Electronic polarizability of compound semiconductors
Authors: Verma A.S.  , Sharma Sheetal  , Jindal V.K.
Published: February 2025

In this paper we present a new expression relating the electronic polarizability (αe) in terms of ionic charge (Z), melting temperature (Tm) and mean atomic volume (Ω) for zinc blende (AIIBVIand AIIIBV) structured solids. The electronic polarizability of these solids exhibit a linear relationship when plotted against the kBTm/Ω (kB= Boltzmann's constant), but fall on different straight lines according to the product of the ionic charge of the compounds. We have applied the proposed relation on these solids and found a better agreement with the experimental data as compared to the values evaluated by earlier researchers.
Vowel-Consonant Speech Segmentation by Neuromorphic Units
Authors: Gómez-Vilda Pedro  , Rodellar-Biarge Victoria  , Muñoz Mulas Cristina  , Mazaira Fernández Luis Miguel  , Ferrández-Vicente José Manuel
Published: February 2025

Speech perception is still a much complex process far from being fully understood. To gain some insight on specific open problems in its automatic treatment (recognition, synthesis, diarization, segmentation, etc.) neuromorphisms and knowledge derived from the understanding on how the Auditory System proceeds may be of crucial importance. The present paper is part of a series of preliminary work carried out trying to translate some of this understanding to solve specific tasks as speech segmentation and labeling in a parallel way to the neural resources found in the Auditory Pathways and Cortex. The bio-inspired (neuromorphic) design of some elementary units (responsible for receptive field implementation) covering simple tasks as static and dynamic formant tracking, or vowel labeling is exposed. In a further step it is shown how simply neural circuits employing these units may convey successful vowel-consonant separation independently of the speaker. The paper is illustrated with results from simulations.
Numerical modeling of skirted foundation subjected to earthquake loading
Authors: Azzam W.R.
Published: February 2025

This paper explores the possibilities of using skirted foundation system to mitigate the liquefaction hazards, control the horizontal soil movement and decrease the pore water pressure underneath the foundation during the earthquake. This technique is investigated numerically using finite element analysis. Four stories reinforced concrete building resting on raft foundation is idealized as two-dimensional model with and without skirts. In the present study, two dimensional plane strain program PLAXIS, dynamic version is used. A series of models for the problem under investigation was run under different skirts depth below the foundation level. The results showed improved effectiveness in liquefaction mitigation due to confinement effect and decreasing horizontal soil movement. The presence of such skirts can modify and decrease the induced excess pore water pressure. In addition, the skirts can significantly reduce the foundation acceleration and the ground motion amplification is reversed.
Rigid inclusions in sand formation resting on compressible clay
Authors: Bouassida Mounir
Published: February 2025

A typical soil profile composed by relatively thick sand layer resting on very thick compressible clay layer is considered. In such geotechnical condition the construction of very high embankments induces unallowable consolidation settlement. Then a novel foundation system is suggested by installing floating rigid inclusions in the upper sand layer so that skin friction and tip components will develop along the inclusion as reaction to the concentrated vertical load applied on capped mini slabs. For the design it will be of interest to determine the optimum length of rigid inclusions and spacing to come up with negligible settlement at surface of the sub clayey layers. The analytical prediction of bearing of bearing capacity of rigid inclusions in sand formation is presented. The consolidation settlement of clayey layers is estimated.
Shaft Resistance of Model Pile in Wet Soil
Authors: Shahin Mohamed M.
Published: February 2025

The shaft resistance of smooth and rough model pile in wet sand, silt and clay under static loading is investigated experimentally in a pile-soil shaft resistance test apparatus. This apparatus allows independent control of the boundary stresses of a cylindrical soil specimen in the vertical and horizontal directions. The pile installation technique used was designed to minimize soil disturbance so that the failure criterion for pile shaft friction could be investigated. The load transfer along the shafts of smooth and rough surfaces aluminum model piles in wet soil under static load was measured. The study shows that, the magnitude of pile-displacement at failure, which necessary to mobilize the ultimate shaft resistance varies significantly with the soil type and surface roughness of the pile. The study also, shows the importance of the boundary conditions of the soil specimen surrounding the model pile. The results shows the effectiveness of using rough pile in increasing the pile capacity. Also, The results show that the angle of the pile-soil contact depends on the soil type, roughness of the pile surface, void ratio, initial density, and horizontal confining pressure.
Deformations of Soil Reinforced Walls in Relationship with Reinforcement Used
Authors: Zannoni Edoardo  , Vicari Marco  , Scotto Moreno
Published: February 2025

Deformations become the main design parameter when serviceability limit state analysis becomes more restrictive than ultimate limit state analysis. In this paper, deformation of soil reinforced walls will be related to the properties of the reinforcement material. A 5m high soil reinforced wall will be analysed to relate deformation using a double twisted hexagonal wire mesh and a geosynthetics bonded geogrid as reinforcements. The performances of the double twisted hexagonal wire mesh will be evaluated using test in air and confined in soil. The maximum deformation of the wall is 75% higher in air than in confined soil condition. The confined soil condition represents a more realistic behaviour of the reinforcement. Short-term deformation of a geosynthetics bonded geogrid happen during construction and cannot be highlighted due to the soil consolidation process. Therefore, only a long-term analysis is conducted where only viscous deformation due to creep are accountable.
Deep Excavations in Luanda City Centre
Authors: Pinto Alexandre  , Pita Xavier
Published: February 2025

The aim of this paper is to present some case studies of deep excavations in Luanda down town, where the geological and geotechnical conditions are very complex, mainly due to surficial location of the ground water table, installed on granular and high permeability soils. The adopted solutions allowed the control of the deformations both at the earth retaining structures and at the neighborhood structures and infrastructures, as well as the control of the ground water inflow to the excavation pit, allowing the safe fulfilling of both the works schedule and budget.
The use of reinforced soil to construct steep sided slopes in order to create a safer highway – Ruhengeri to Gisenyi road, Rwanda
Authors: Assinder Peter  , Schippers Heribert  , Ballestra Giuseppe
Published: February 2025

Parts of the existing Ruhengeri to Gisenyi road in the North Western part of Rwanda winds along steep mountainous hillsides which stand at ~8,000 feet. The large number of trucks travelling to the Democratic Republic of Congo has resulted in the edge of the road falling away down the hillside. The project formed part of the African Development Bank and European Commission collaboration for Rwanda's transport improvement program, with this particular part of the project financed by the European Commission. Part of the large rehabilitation project to reconstruct and improve the general alignment and safety of the road, included a 350m section where a reinforced soil solution was adopted. The 70° steep reinforced soil slope raised to a maximum height of 8m. The use of reinforced soil allowed the road to be widened and the use of locally won fill from a local quarry to be used, thus negating the use of concrete structures or other expensive material solutions. Additionally, a vegetated slope face allowed the structure to blend in with the existing landscape.
Derived Empirical Relations and Models of Vital Geotechnical Engineering Parameters Based on Geophysical and Mechanical Methods of Testing
Authors: Mukabi John
Published: February 2025

Due to the increasing frequency of seismic action and other natural hazards on one hand, and population explosion culminating in the development of megacities on the other, the need for mega structures cannot be overemphasized. Precise determination of geotechnical engineering parameters for the design and construction control for foundations of high rise buildings, bridges, highways, tunnels, underground space development and other civil engineering structures is one of the greatest challenges to engineers and scientists. As a result, various destructive and non-destructive methods of laboratory and in-situ testing have been developed. However, the cost of constructing such structures is usually high and depends on the precision of the design parameters adopted. This Study proposes some empirical equations that can be useful in determining not only the elastic stiffness directly from geophysical measurement but also derive such essential parameters as bearing capacity and shear strength from the same.
Fundamental Theory of the ReCap Technique and its' Application in the Construction of Pavement Structures within Problematic Soils
Authors: Mukabi John N.  , Njoroge Bernard  , Zelalem Tilahun  , Kogi Samuel  , Ndeda Maurice  , Kamau David
Published: February 2025

Most road pavement failures are propagated through the physical infiltration of water into expansive subgrade soils (moisture increase and suction decrease). In road design and construction, the normal and conventional practice in providing counter-measures to the inferior properties of problematic soils in Africa is to replace them altogether with a capping layer consisting of superior materials meeting the required specifications.
Modélisation Numérique du Renforcement des Chaussées non Revêtues par Géogrille
Authors: Remadna Mohamed Saddek  , Benmebarek Sadok  , Belounar Lamine
Published: February 2025

Le présent travail s'intéresse à la simulation numérique à l'aide du logiciel FLAC, de l'amélioration de la portance du corps d'une chaussée non revêtue renforcée reposant sur un sol support de faible portance. L'étude permet de déterminer le comportement pression–déplacement en petite et en grande déformation pour les chaussées avec ou sans renforcement. Il en est déduit l'amélioration apportée par le renforcement. L'analyse des contraintes tangentielles et normales sur l'interface sol–base permet d'expliquer le rôle joué par le renforcement dans l'amélioration de la portance ou ce qui est communément appelé mécanisme de renforcement. L'étude permet aussi de montrer l'effet de la raideur et de la longueur d'ancrage de la géogrille sur le renforcement.
Hydraulic Conductivity of Compacted Foundry Sand Treated with Bagasse Ash
Authors: Osinubi Kolawole  , Moses George
Published: February 2025

The hydraulic conductivity of compacted material is the most important parameter in assessing its suitability for use in engineered waste containment facility. Foundry sand mixed with up to 8% bagasse ash by weight of dry soil was evaluated for use as a suitable hydraulic barrier material. Tests were carried out on the foundry sand – bagasse ash mixtures to determine the index properties and compaction characteristics. The relationship between between hydraulic conductivity of the mixtures compacted using the British Standard light (BSL) energy with moulding water content, bagasse ash content and unit weight were determined. Test results show that the regulatory minimum hydraulic conductivity (k) value of 1 × 10−9m/s or lower required for a material to be used in waste containment application can be achieved when foundry sand is treated with 4 % bagasse ash, prepared at molding water content in the range 11.2 – 15.4% and compacted to a unit weight of at least 17.56 kN/m3.
Subsurface Conditions in Central Khartoum
Authors: Mohamed Eisa A.  , Elsharief Ahmed M.
Published: February 2025

Khartoum city lies between the Blue Nile and White Nile at the confluence of the two rivers. The city is nowadays experiencing huge development projects. Several structures of all types are currently under construction e.g. towers, bridges and underground structures. The understanding of the subsurface conditions is fundamental for good planning and design of these structures. Central Khartoum is dominated by thick layer of Miocene-Quaternary sediments geologically recognized as Upper Gezira Formation, underlain with sandstone (Lower Omdurman Formation). Geotechnical data from several service reports carried out in Central Khartoum were collected and analyzed. Variations in layering and geotechnical properties of the Upper Gezira Formation were statistically examined. It has been found that the Gezira Formation is constituted of an upper thin crust of hard silty sandy clay of medium to high plasticity overlying deposits of silt, silty sand and poorly graded sand. Contours are given for the depth of the upper clay crust, depth of the Nubian Sandstone Formation and depth of the water table. Important geotechnical factors governing and controlling the design of different foundation systems on the encountered soils were highlighted. These factors include presence of pockets and/or areas dominated by potentially expansive soils and loose silty sands.
Modularity Issues in Biomedical Ontologies
Authors: Schulz Stefan  , López-García Pablo
Published: February 2025

This keynote addresses modularity issues focusing on biomedical ontologies, with a particular consideration of SNOMED CT. Emphasis is put on approaches that carve out high-coverage subsets addressing specialty-specific documentation needs.
Mechanical properties of a saturated lime-treated clay
Authors: Mavroulidou M.  , Zhang X.  , Gunn M.J.
Published: February 2025

This paper investigates the effect of lime treatment on the mechanical properties of saturated London Clay specimens. Samples of London Clay and lime-treated London Clay samples were statically compacted at the same target voids ratio. They were then saturated and subject to consolidated drained triaxial tests. The results showed that the stiffness and shear strength were improved upon lime treatment. However as opposed to the untreated soil, the lime-treated specimens showed a strain-softening behaviour. Consequently, at large strains both treated and untreated soil specimens converged onto the same critical state line on the q-p' plane. This implies that lime does not appear to have modified the frictional properties of the material. Conversely in the v-lnp' plane the Critical State Line was parallel to the Isotropic Compression Line (as expected) for both materials but the slope of the lime-treated soil was less steep than that of the untreated soil, so that, the lime-treated specimens maintained higher specific volumes during compression and shearing. Overall it can be concluded that the addition of lime had a beneficial effect on the mechanical properties of the clay soil, whereas it also improved the volumetric stability of the expansive clay soil.
Comparaison des comportements de matériaux Soil-Mixing réalisés sur chantier et en laboratoire: étude d'un limon traité au ciment
Authors: Szymkiewicz F.  , Reiffsteck P.  , Le Kouby A.  , Fanelli S.
Published: February 2025

Un chantier d'amélioration de sol utilisant la méthode Trenchmix a été l'occasion de comparer les propriétés mécaniques du matériau Soil-Mixing réalisé sur chantier et celui réalisé en laboratoire à partir d'un échantillon de sol prélevé sur le chantier et mélangé avec le même ciment et à des dosages équivalents. Des essais in situ au pénétromètre dynamique léger ainsi que des observations en laboratoire sur des prélèvements effectués in situ ont permis de caractériser l'homogénéité du matériau et de déterminer son impact sur la résistance du matériau et son comportement.
Load distribution on the geosynthetic reinforcement within a piled embankment
Authors: van Eekelen S.J.M.  , Lodder H.J.  , Bezuijen A.
Published: February 2025

This paper considers the load distribution on the geosynthetic reinforcement (GR) in an embankment support with piles. The paper describes the test set-up and test procedure of a test series of twelve 3D piled embankment tests. The measured strains show that the tensile forces concentrate within the GR strips between adjacent piles. The measured shape of a deformed GR strip shows that its net load must have been an approximately inverse triangular-shaped load. This means that most of the load worked on the GR part close to the piles. This differs from the assumptions for the load on the GR strips in BS8006 (2010, equally distributed load) and EBGEO (triangular shaped load). When assuming an inverse triangular load in stead of a triangular load, a saving of 15 to 25 % of the required GR strength will be gained for a realistic geometry of a piled embankment.
Rockfill and soil-rock mixtures in road embankments – a case study
Authors: Fortunato E.  , Caldeira L.
Published: February 2025

The development of transportation infrastructures has led to the need of huge earthmoving volumes, resulting in high embankments. In the construction of these embankments, rockfill and soil-rock mixture materials have been used. A 25 km roadway section, in the North of Portugal, with the difficult topographic conditions, has required the construction of large embankments. The involved formations are essentially granite (South area) and schist and greywacke (North area). To optimize the construction procedure and to evaluate their performance, physical and mechanical characterization of the materials was carried out and monitoring equipments were installed in some embankments. For that purpose, five embankments were selected, taking into account, essentially, the geometry and type of material used in their construction. Plate load tests were also performed, aiming at the evaluation of the deformation modulus of the embankments. In order to measure displacements, vertical and horizontal inclinometers, extensometers and pressure cells systems were installed during construction. After construction, topographic marks on the embankment surface were installed. In this paper, the results of the mechanical characterization carried out in situ and in the laboratory (large triaxial and oedometer tests) are presented. The installed monitoring equipments are also described. The displacements during the construction and deformations in service are herein presented.
The dissolution of gypsum of Disueri reservoir left bank
Authors: Valore C.  , Ziccarelli M.  , Gambino C.
Published: February 2025

Results of a laboratory research programme on the rate of dissolution of a selenitic gypsum are reported and discussed. The tested gypsum samples have been recovered from boreholes drilled in a thick layer outcropping on the left bank of Disueri reservoir located near Gela in Sicily. The tests carried out demonstrate that the rate of dissolution Rddepends essentially on the velocity v of water flowing along the surface of the gypsum. Values of Rdrange from 0.94 to 3 kg/(m2• day) for v values from 0.05 to 0.20 m/s. Such high rates can account both for rapid evolution of the existing cavities and for creation of new caves within the gypsum mass following the impounding of the reservoir, and for the ineffectiveness of the grout curtains and of the waterproof facing of the outcropping front of the gypsum layer intended to prevent reservoir water from entering the gypsum mass.
Combined slope protection along the southern Bulgarian Black sea coast
Authors: Frangov G.  , Zayakova H.  , Hamova M.
Published: February 2025

Some sections of the Bulgarian Black sea coastline are subjected to intensive sea erosion. Slope cutting during storm events provokes the origination of landslides that threaten buildings, roads and other facilities. This is the case with the northern coast of the town of Tsarevo. Local slides and rock-falls have been documented in the coastal zone. They are activated in periods of heavy precipitation and their sliding surface passes on the top part of grey-green marl-like clays. It is envisaged to stabilize the slope by sea defence, construction of reinforced abutment embankments and drainage ribs for water removal.
Geotechnical conditions for E-763 motorway construction from Belgrade to South Adriatic across the landslide Umka – Duboko
Authors: Jelisavac B.  , Mitrovic P.  , Vujanic V.  , Milenkovic S.  , Jotic M.
Published: February 2025

Serbia is known for numerous landslide phenomena. This is particularly stressed in the valley banks of rivers Sava and Danube and their respective tributaries. By both General and Preliminary designs of motorway from Belgrade to South Adriatic, i.e. E-763, at the exit from Belgrade, road facility corridor is located at the right bank of Sava river, on the meandering apex, crossing the landslide Umka - Duboko in the length of 3 km. Large active landslide in the depth of 10-26 m, created in marly clays, takes up the area of 1.8 sq.km.
Rehabilitation of a landslide in NW Greece – From the investigation to the geotechnical design
Authors: Seferoglou K.  , Prountzopoulos G.  , Chrysochoidis F.  , Fortsakis P.  , Vassilopoulou I.  , Perleros V.
Published: February 2025

The article describes the investigation of a landslide incident in Epirus (NW Greece), on the national road connecting Preveza and Igoumenitsa. The main geomaterials involved are cyan marl to very stiff clay, green gravely clay and the clayey embankment material. The landslide destroyed part of the road embankment covering the natural slope above the Despo stream. The failure evolved in two phases, the first occurring in the winter of 2004, 30 years after the embankment construction, most possibly due to significant fill loading at its toe and heavy rainfalls. After its reconstruction, accompanied by mild rehabilitation works, a landslide reactivation took place in winter of 2005-06. The resulting scarp, ~30m in width and ~10m in height, developed within the embankment. Moreover, indications of minor destabilisation were observed on the so far stable part of the embankment, suggesting a potential extension of the landslide eastwards. The information collected during numerous site visits, the evaluation of a full-scale geotechnical survey (boreholes, laboratory testing and instrumentation including piezometers, inclinometers, crackmeters and optical targets) and the back analyses performed, led to the understanding of the failure mechanism. Possible solutions were then investigated, concerning both the main landslide area and its possible extension. The rehabilitation approaches varied from purely geotechnical e.g. slid mass removal and construction of a new reinforced embankment, to mainly structural, such as bridge construction to totally replace the embankment.
Long term behaviour of temporary prestressed anchors – “Keramikos” underground car park station
Authors: Zampiras E.  , Boussoulas N.
Published: February 2025

This paper focuses on the long term behavior of temporary prestressed anchors of an existing temporary retaining structure. The scope of the initial project in 1995 was to construct “Keramikos” underground station of Line 3 Athens Metro. In 2007 ATTIKO METRO S.A. had the responsibility to construct within the existing excavation, a new five storey underground car park. The main distinctiveness of the particular project was that for the first time in Greece a temporary retaining structure of a deep excavation active for almost 13 years, being subjected to different loading conditions, had to be used again under submerged conditions. The recorded actual behavior of the retaining structure showed that the global remaining temporary anchor strength was quite significant.
Geotechnical monitoring of a conduit on the construction site of Moscow International Business Center in “Moscow City”
Authors: Isaev O.N.  , Nayatov D.V.  , Sharafutdinov R.F.  , Ibraev R.R.
Published: February 2025

Intensive development of underground space in big cities often negatively affects existing underground service linescauses their failures, damages existing buildings and those under constructed. NIIOSP is involved in active investigation of existing service lines safety both at project design stage and during construction of underground and deep buildings and structures.
The influence of microfabrics in bonded soils behaviour, based in laboratorial comparison of artificially and naturally cemented specimens
Authors: Cruz N.  , Rodrigues C.  , Viana da Fonseca A.
Published: February 2025

Cemented soils are often seen as non-textbook materials, since they don´t fit into the usual behaviour of transported soils in the light of classical Soil Mechanics theories. The major problem of establishing a mechanical behaviour pattern of cemented sandy soil based on recoiled natural samples is the variability of its fabric and the existence of a dispersion of particulate strength, aggravated by inevitable sampling induced disturbance. The use of artificially cemented soils has been frequently used as a mean to overcome these drawbacks. However, this approach may be criticized due to an important handicap, that is the difficulty of artificially recreating natural microfabrics. Herein, a laboratorial framework performed on Guarda granitic residual soils, integrated in a wider research PhD program (Cruz, 2010) is presented, aiming to study the influence of microfabric in artificially and naturally cemented soils strength and stiffness properties. The program involved an extensive laboratorial testing program performed over remoulded soils of weathered granite mixed with Portland cement under distinct contents. Overall, 50 uniaxial, diametral and triaxial (CID) compression tests with internal or local instrumentation (LVDT) were executed over these admixtures.
Mechanical properties of MSWI bottom ash in Denmark
Authors: Larsen P.
Published: February 2025

In Denmark, traditionally Municipal Solid Waste Incineration (MSWI) bottom ash has been used as structural fill and especially as capillary layer beneath floors. The latter practice started in the 1960ties in urban family houses and has continued for more than 20 years. Gradually, the tradition using bottom ash beneath floors has been adopted for large storehouses as well.
Measurement of stiffness of Greek stiff soils
Authors: Georgiannou V.N.  , Ferreira P.  , Altuhafi F.
Published: February 2025

Research into the stress-strain behaviour of many stiff clays and weak rocks has demonstrated conclusively that it is highly nonlinear. Hence, to calculate ground movements it is necessary to define stiffness parameters at strains which correspond to the strains caused by the construction. In this paper the stiffness of five soils from various Greek construction sites was evaluated through improved equipment and test techniques. These included measurement of shear wave velocity and the use of local strain instrumentation. The latter comprised of miniature inclinometers and LVDTs. Tests were performed on natural (undisturbed) specimens trimmed from block samples. The specimens were isotropically and anisotropically consolidated and stiffness parameters were measured for each soil for a range of effective stress levels. Despite the wide variation of the deposits all soils contain less than 20% clay content and their Atterberg limits plot very close to the A line. The measured stiffness values fall within the broader band of data reported in the literature for stiff clays.
Rapid estimation of residual shear strength by ring shear test
Authors: Iyisan R.  , Cevikbilen G.  , Hatipoglu M.
Published: February 2025

The residual shear strength of the soils is one of the main inputs for analyzing the stability of pre-failed slopes and the progressive failure problems, which generally occur in fissured clay slopes, caused by strength reduction with displacement. In practice, it is important to decide the residual shear strength parameters as quick as possible in an acceptable precision. The ring shear and the reversal direct shear tests are common methods to determine the residual strength parameters in the laboratory. The unlimited rotational shear, continuous displacement, constant cross-sectional area of the shear plane and uniform normal stress distribution during the test make the ring shear test more reliable than the reversal direct shear test to obtain the residual condition. This study presents the preliminary results of consolidated drained reversal direct shear and consolidated undrained ring shear tests carried out on twenty prepared soil samples having different clay fractions and plasticity indexes to determine residual shear strength parameters. The shear displacement rates were selected as 0.035 mm/min in reversal direct shear test and 20 mm/min in ring shear test. The relationship between residual shear strength angles of the tests illustrates that the ring shear tests performed at relatively high shearing rate are remarkable. The relationships between the residual shear strength angle, the liquid limit and the plasticity index were examined and obtained results were compared by the previous studies.
Cyclic behaviour of saturated sands subject to previous horizontal shear stresses
Authors: Soriano A.  , Patiño H.  , González J.  , Valderrama M.
Published: February 2025

The dynamic behaviour of saturated sands has been studied from different perspectives. However, most experimental research on this field does not take into account the shear stress conditions existing prior to the application of dynamic loads; i.e., a null initial static shear stress (τo=0) is assumed. The main objective of this work is to report on the influence that static shear stresses (τo) have on the behaviour of saturated sands under cyclic shear loads. This article presents the results and analysis of part of a wider experimental programme involving 30 monotonic and 26 cyclic simple shear tests for different combinations of static shear stress (τo) and cyclic shear stress (τc) (all undrained), besides identification and classification tests. The tested samples have been taken from the area of the North Entrance Mouth at the Port of Barcelona (Spain).
Stiffness of overconsolidated hard sandy clay soils
Authors: Thompson R.P.  , Belton J.M.  , Booer A.F.
Published: February 2025

Engineering projects often require soil stiffness values at small straintheir variation with strain levels. Information can be based on empirical relationships or obtained from advanced testing. The paper reviews various degradation relationships. Results from investigations located towards the edge of the London Clay Formation basin are given where the soils comprised sandy clay. Marked differences were found compared to information published for the more plastic facies of the Formation.
An extended Drucker-Prager hardening model for cross-anisotropy of soft rocks
Authors: François B.  , Collin F.  , Dizier A.  , Charlier R.
Published: February 2025

The mechanical behaviour of natural geomaterials is often anisotropic. Sedimentary rocks usually show a limited form of anisotropy, called cross-anisotropy. This paper presents an original constitutive model based on a hardening Drucker-Prager elasto-plastic framework that has been adapted to consider cross-anisotropic elasticity as well as an anisotropic plastic criterion. The cohesion is a function of the angle between the direction of the major compressive stress and the normal to the bedding plane. This original model consists in a relatively simple upgrading of a well-known elasto-plastic model, well-adapted for sedimentary hard soils or soft rocks. The ability of the model to reproduce the directional dependency of the elasto-plastic response of clay rocks, as observed in triaxial tests, is proved by numerical simulations of experimental tests.
Geotechnical conditions for the construction of tunnel “Progon” on the Dimitrovgrad bypass in Serbia
Authors: Milenkovic S.  , Jelisavac B.  , Vujanic V.  , Jotic M.
Published: February 2025

Within the designed alignment of E-80 motorway in South East Serbia: Section Dimitrovgrad By-Pass the roadway alignment for the motorway and respective structures has been adopted. In the area of the abovementioned section it is foreseen to build the roadway in twin-tube tunnel Progon with total length of 1100 m.
Neural modelling of the fly ash compaction curve
Authors: Zabielska-Adamska K.  , Sulewska M.J.
Published: February 2025

The paper aim was to analyze the influence of fly ash grain-size distribution (representing by the effective sizes, uniformity and curvature coefficients) and specific density on its compaction curve shape. The tested fly ash was compacted by the Standard and Modified Proctor methods at various water content ranging over±5%. The attempt of applying the artificial neural networks type MLP for fly ash compaction curve points was made. ANNs several inputs (grain-size distribution as D10–D90and uniformity and curvature coefficients, compaction method, fly ash specific density) were used. The output vector was presented by co-ordinates of generated compaction curve points. Using ANN modelling method, models which enable establishing the approximate compaction curve shape were obtained.
Empirical determination of the undrained shear strength of very stiff to (very) hard cohesive soils from SPT tests
Authors: Plytas C.  , Baltzoglou A.  , Chlimintzas G.  , Anagnostopoulos G.  , Kozompolis A.  , Koutalia Ch.
Published: February 2025

The Standard Penetration Test has become increasingly popular in testing stiff to hard cohesive soils. Several correlations have been proposed that associate undrained shear strength with SPT blowcount in such soils. These correlations, often produced through significant data scatter, are typically restricted to specific materials and their main drawback is their not taking into account physical characteristics, often conveniently reflected in trivial lab processes, e.g. clay mineralogy manifested through Atterberg limits. A simplified empirical relationship is presented that correlates the undrained shear strength (cu) of cohesive formations and the ‘as-measured’ SPT blowcount (N) attempting to reduce statistical scatter by addressing the important influence of characteristic physical properties on soil strength. The correlation derives from the statistical processing of data obtained in three different stiff to very hard cohesive formations in Greece, essentially clays and marls, each exhibiting a consistently identifiable geotechnical behaviour, in which a large number of ‘coupled’ SPT and lab UU triaxial tests were performed. Processing of the available data supports the common observation that the definition of a constant cu/ N ratio (even within the same material) is unrealistic. The inclusion of both water content (w) and plasticity index (PI) in such correlations is investigated and found to significantly improve the consistency of correlation results, indicating a linear dependence of the cu/ N ratio on (w) and logarithmic dependence on (PI). The identification of additional independent parameters affecting the procedure is also examined and basic directions for the orientation of future correlations are outlined.
Etude experimentale du comportement des sols gonflants sur le site de Ouarzazate. Maroc
Authors: Ejjaaouani H.  , Shakhirev V.  , Magnan J.P.
Published: February 2025

Les sols argileux semi-secs que l'on trouve dans les régions à climat aride absorbent très activement l'eau et la laissent difficilement partir par évaporation.
Facteur d'influence des paramètres de forage
Authors: Reiffsteck Ph.
Published: February 2025

Cette communication présentera une étude approfondie des facteurs d'influence et des corrélations possibles à partir de la technique des paramètres de forage. Une sondeuse géotechnique hydraulique instrumentée a été utilisée sur des planches expérimentales constituées de différents matériaux et stratification. L'observation de la variation des paramètres de fonctionnement de la machine permet d'avoir une idée assez précise de la position des transitions des couches de sols ou de roches de natures différentes. De même, la combinaison de ces paramètres permet d'approcher la variation de certains paramètres mécaniques et hydrauliques de ces terrains. Le programme de travail mis en œuvre lors de l'étude a été le suivant:
Comportement d'un matelas de répartition audessus d'inclusions rigides et supportant, ou non, une structure en béton: méthode analytique de calcul
Authors: Berthelot P.  , Durand F.  , Glandy M.
Published: February 2025

On présente une méthode analytique de calcul de la résistance au poinçonnement d'un matelas de répartition constitué par une couche de forme éventuellement renforcée par un remblai compacté et situé entre l'ouvrage à fonder et les inclusions rigides. Cet élément vertical est mis en œuvre pour supporter soit un remblai soit une structure en béton.
A new assessment of ultimate unit friction for driven piles in low to medium density chalk
Authors: Carrington T.M.  , Li G.  , Rattley M.J.
Published: February 2025

A number of methods currently exist for the assessment of ultimate long term static axial pile capacity for driven piles installed in chalk stratum. In each of these methods the derivation of shaft resistance is based upon estimation of the in-situ horizontal stress and the pile interface friction angle (δ) and it is conventional to impose arbitrary limits upon the ultimate unit friction to account for reduction in particle cohesion due to remoulding during pile driving. This paper presents the results of preliminary laboratory testing undertaken to examine the effects of driven pile installation on the static simple shear strength mobilised in low to medium density chalk after remoulding during high intensity pile driving. Data from the tests are interpreted with reference to the stress state behaviour of the chalk and show consistent trends which allow a more accurate, and less conservative, assessment of ultimate unit friction compared to current design methods
Hydraulic properties of upper eocene flysch, at Papadates, Preveza Province, Greece
Authors: Barounis N.  , Barounis A  , Karadima K.  , McMahon P.H.
Published: February 2025

For the construction of Papadates dam a site investigation was conducted by means of three boreholes in which double packer p meability testing was conducted. The dominant geological formation found was Upper Eocene Flysch consisting of siltstone and san stone alternations. In this paper the results of the permeability tests are presented and the hydraulic behavior of the Flysch was c fied of three distinct modes: turbulent flow, laminar flow and fracture expansion. Attempts for correlating RQD with permeability proved to return poor Pearson coefficients.
Effectiveness of CPT-Based classification methods for identification of subsoil stratigraphy
Authors: Tumay M. T.  , Karasulu Y. H.  , Młynarek Z.  , Wierzbicki J.
Published: February 2025

The paper presents an analysis of effectiveness of the application of seven commonly used CPT-Based classification systems for the assessment of subsoil stratigraphy and lithology. The analysis was conducted with the following classification systems: Begemann 1965, Douglas/Olsen 1981, modified Schmertmann 1985, Robertson et al. 1986, Robertson 1990, Eslami/Fellenius 1997, and, Zhang/Tumay 1999. The analysis was performed for subsoil composed of slightly and strongly overconsolidated moraine tills and glacifluvial sands and gravels. In the investigated area a total of nine piezocone penetration tests, PCPT (or CPTU) tests were conducted and samples were collected for laboratory analyses. The reference point for soil behavior type classification systems was provided by the results of grain size distribution of the soil. The basic element in the analysis was to determine the effect of the type of the applied soil behavior type classification system on the construction of the subsoil stiffness model. Three systems were selected as best performing for the purpose of this analysis: Douglas/Olsen 1981, Robertson et al.1986, and Zhang/Tumay 1999. The construction of subsoil stiffness models was based on the statistical Inverse Distance Weighted method (IDW) by Młynarek, et al., 2007.
Electrical resistivity tomography: monitoring of hydro-chemical processes and parameter estimation
Authors: Della Vecchia G.  , Cosentini R.M.
Published: February 2025

Electrical resistivity tomography (ERT) is a useful tool for site characterization and monitoring. This paper describes some 3D laboratory applications of ERT, used to monitor wetting processes in unsaturated soils and the transport of contaminants in water-saturated samples. ERT was used to create maps of electrical conductivity of the monitored domain at different time intervals. Electrical conductivity changes were used to infer degree of saturation or concentration variations within the pore space. Test results confirm the applicability of the technique for problems involving movement of water in unsaturated soils, salt transport and oil migration. The observations in laboratory under controlled conditions proved very useful for validation and calibration of models to be used for full-scale analyses. As a further application, ERT was used for the hydraulic characterization of unsaturated soil samples, in terms of hydraulic conductivity and retention curve. The results are compared to the retention curve as obtained with the classical approach of axis translation technique and provide an encouraging agreement.