bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient pre-processing for finite element analysis of shallow tunnelling
Authors: Koungelis D.K.  , Augarde C.E.
Published: February 2025

This paper introduces a parameterised scheme for automated 3D mesh generation of tunnelling layouts using a freeware mesh generator. Comparisons are made with meshers found in commercial FE software. Various tests were undertaken here to examine the capabilities of the mesh generator employed for tunnelling analyses in particular. From these it is found that this software can rapidly and easily produce 3D meshes of good quality even for the most unfavourable positions of a tunnel in the domain, and for the most complicated tunnelling schemes.
Ground conditions due to tunnelling in hard soils and weak rocks
Authors: Lagioia R.  , Potts D.M.
Published: February 2025

This paper examines the influence of soil structure on tunnel excavation. Finite Element analyses are presented in which soil behaviour is reproduced by means of a constitutive model specific for “hard soils” / “soft rocks”. This simulates structure by postulating the existence of an expanded yield surface, and structure degradation by means of two appropriate hardening rules. Different structure conditions in the ground are considered, such as those occurring in cemented sedimentary and in residual soils. The profile of the yield surface size is then set accordingly. The effect of grouting in a weak residual soil is also investigated.
Chemical Stabilisation of Closed Landfill Sites Using Chemical Agents
Authors: Khabbaz H.  , Fatahi B.
Published: February 2025

Closed landfill sites can be developed as public parks and useful lands near urban areas. However, there are a number of considerable challenges in redevelopment of closed landfill sites including complexity in settlement behaviour, weak shear strength, high permeation, gas emission as well as health and safety issues. This paper presents an effective stabilisation method for old landfills. It also compares permeability, compressibility and compressive strength behaviour of municipal solid waste samples and organic soils with or without chemical stabilisation. An array of laboratory tests has been conducted on municipal solid waste samples and organic soils mixed with different percentages of fly ash-lime to determine their engineering characteristics. According to the experimental results, it is found that the chemical stabilisation can decrease the permeation, whereas increase the dry density and the compressive strength of municipal solid waste samples and organic soils.
Deposition tunnel backfill development: ¼-scale tests in Riihimäki
Authors: Korkiala-Tanttu L.  , Nemlander R.  , Keski-Kuha E.  , Keto P.  , Koho P.
Published: February 2025

Posiva Oy is responsible for the final disposal of Finnish nuclear waste, including backfilling of the deposition tunnels. To test the functionality of the pre-compacted block backfill concept, Posiva Oy launched the BACEKO-project in Riihimäki. The BACEKO-project consisted of a series of ¼-scale tunnel tests that were executed during the years 2008 and 2010. The objective of these tests was to investigate the operation of the block backfill concept in small scale, observe the saturation process and to compare the tolerance of erosion in different materials. The materials used for pre-compacted blocks in these tests were Friedland clay, mixture of bentonite and crushed rock (40/60) and Milos B clay. The types of tests executed were saturation, flow-through and open-front tests. The saturation tests lasted 1-4 months. The flow-through tests lasted 5-10 days establishing information on piping and erosion in different backfill materials. The aim of the open-front tests was to define the time span during which the installation can be interrupted without causing major detriments to the backfill. The saturation tests showed that the saturation proceeded 70-150 mm in a month. In flow-through tests Friedland clay blocks were discovered to be more sensitive to erosion than blocks made of bentonite and crushed rock (40/60). However, the Friedland clay backfill produced significantly higher swelling pressures. The open-front tests showed that with the inflow rate of 0,25 l/min the backfill front can be left open for less than 24 hours without major detriments.
In-situ tests on the Parthenon columns for the assessment of their foundation condition
Authors: Egglezos D.  , Toumbakari E.-E.
Published: February 2025

The paper reports a) the in-situ trial load tests, which were carried out on the four, out of six, columns of the Parthenon western side, the Opisthodomos, during the recent restoration project (2001–2004) and b) the analytical assessment of their structural response, including foundation, based on the obtained experimental data.The dismantling of the entablature members during the anastylosis project, gave the opportunity for the performance of in situ trial load tests in order to study the response of the columns, interacting to their foundation. The testing project consisted of the application of a horizontal force of 10-11kN at the capital of each column. At the same time, the horizontal displacement of the capital and the vertical displacement of the base marble block, were measured The test was carried out twice in each direction, to account for differences in the foundation conditions. For the evaluation and the interpretation of the test results a back-analysis was performed. For the (3-d nonlinear elastic) analysis Rock-Mechanics principles were applied. The idea is that dry masonry structure, from natural rock stone blocks connected with frictional “joint” forces are analogous to a jointed rockmass system. The comparison of measured values and analytical predictions are generally in good agreement, offering increased accuracy.According to the results, discrete modelling with properly determined parameters for monument's geomaterials can satisfactorily be applied to restoration analyses of this type of structure and could form the base for more complex calculations involving dynamic effects e.g. earthquake.
Dynamic analysis of San Pedro Cliff at La Alhambra
Authors: Justo J.L.  , Morales-Esteban A.  , Durand P.  , Vázquez N.  , Justo E.
Published: February 2025

San Pedro Cliff is a dihedral 65.5m high, which has progressed to place itself at a distance of 23.8m from the Alhambra palace that is a World Heritage Site. The western part of the Cliff is a fault-line scarp, modified by river erosion and latterly by successive slab falls. Pseudostatic stability analyses suggest that the factor of safety of this slope under 1000-yr-return-period earthquake loading may drop below 1.0 and the critical slip surface could penetrate the Alhambra walls. To raise the safety factor up to values above 1.0 and to counteract extensional regime in the cliff, a solution with minimal visual impact is proposed, consisting of a high-yield-stress wire mesh, post-tensioned by anchors, and coloured to blend with the cliff. The low safety factors obtained using pseudo-dynamic stability analyses has suggested that true dynamic analyses should be carried out. A method for selecting accelerograms based on acceleration response spectra has been used. The accelerograms have been obtained from the European strong motion database for stations placed on rock. A 2-D Finite Element simulation has performed. The distribution of plastic points during the course of the seismic action or the maximum displacement may be obtained for each accelerogram.
Some comments on the grading entropy variation and crushing of various sands
Authors: Lorincz J.  , Kárpáti L.  , Trang P.Q.  , Imre E.  , Fityus S.
Published: February 2025

The well-known theories do not explain/predict the tendency of particle breakage for initially concave grading curves. The paper presents the interpretation of the results of some particle breakage tests with initially A>0.5 and with initially A<0.5 grading curves. The explanation seems to be the same for these.
Reflections on primary and secondary consolidation
Authors: Mortensen N.
Published: February 2025

The objective of this paper is to establish a simplified model for evaluating whether primary and secondary consolidation may develop as two simultaneous mechanisms. The classical 1D consolidation theory has been recomputed and used to establish a set of equations covering an estimate of the theoretical strain rate. The theoretical strain rate, when applied on time-strain curves from Oedometer testing (Incremental loading) on a high plasticity clay, reveals a match between theory and factual measurements. Referring to the dimensionless time, T, introduced by Terzaghi, the math is typically seen for T < 0.8 considering the pure 1D consolidation theory. For T > 2 the development of strain rate during secondary consolidation can also be predicted by the equations introduced. The measured strain rate for the time 0.8 < T < 2.0 is consistently higher than what should be expected by just using the 1D consolidation theory. Ideas for explaining this observation have been discussed.
Compaction and liquefaction of sand caused by a large number of loading cycles
Authors: Sawicki A.  , Świdziński W.  , Mierczyński J.
Published: February 2025

Compaction and liquefaction of sand caused by a large number of loading cycles were investigated experimentally and theoretical models of these phenomena were proposed. The experiments were performed in the cyclic triaxial apparatus Enel-Hydro, which enables sinusoidal changes of the vertical stress and measurement of both the vertical and horizontal strains. Firstly, the volumetric and deviatoric strains were determined for a dry sand, at different initial states. Experimental results were presented in the form of common curves, and then analytical approximations of these data were proposed as functions of a number of loading cycles and the cyclic deviatoric stress amplitudes. Incremental equations describing the cyclic load induced strains, including compaction, were then derived. Secondly, the saturated samples were investigated in undrained conditions in order to determine curves describing the pore pressure generation caused by cyclic loadings, up to sand liquefaction. Then, the dry soil response was linked with the sand behaviour in undrained conditions, through the assumption that the volumetric strains are zero in undrained conditions. As a result, the incremental equation describing the pore pressure generation, up to the onset of liquefaction, was derived. It was shown that there was a fair agreement between theoretical prediction and experimental results.
The relevance of lithostratigraphy in the assessment and investigation of engineering ground conditions in UK mudstones
Authors: Northmore K.J.  , Entwisle D.C.  , Reeves H.J.  , Hobbs P.R.N.  , Culshaw M.G.
Published: February 2025

Stratigraphy is the study of layered rock sequencesparticularly in terms of their agecorrelation with equivalent rocks elsewhere. It has many different branches of which some of the most fundamental are lithostratigraphybiostratigraphychronostratigraphy. Lithostratigraphic subdivisions are those normally depicted on geological maps and most commonly encountered in ground engineering. However, because of local variations it is arguable that lithostratigraphic classifications are of only limited use for site-specific engineering, given that subdivisions are based on generally broad physical characteristics aimed at wider regional correlations. Practical use of stratigraphic subdivisions in ground engineering is further hindered by periodic changes to their nomenclature that has caused confusion to non-specialists not fully aware of the reasons for making such changes. Despite these apparent limitations, recent research into the geotechnical characteristics of the Lias Group and Lambeth Group deposits in the UK has shown how lithostratigraphy can aid in anticipating regional trends in engineering properties. The studies have also demonstrated how understanding regional geological controls can enhance site specific knowledge, leading to more focussed and cost effective ground investigation planning.
Advances in tunneling simulation – a probabilistic approach
Authors: Huber M.  , Vermeer P.A.  , Stroehle P.M.  , Moormann C.
Published: February 2025

Balancing risk and reliability engineers have to take variability of soil properties into account within the design process.Reliability based design offers a scientific base, which is explained exemplarily within the evaluation of the tunnel face stability. Within this framework, the variability of soil, geometry and construction process is considered in a comprehensive way. Parametric studies enlighten the evaluation of the failure probability and help to understand this concept via showing the influence of the different sources of variability.
Predicting shear strength mobilization of London clay
Authors: Vardanega P.J.  , Bolton M.D.
Published: February 2025

When designing geotechnical structures engineers need to assign soil parameters. Soil design parameters are often inferred through correlations with basic site investigation data. The objective of this work is to determine the shape of the undrained stress-strain curve of a heavily overconsolidated Eocene clay in such a way that it may conveniently be used in simplified deformation mechanisms to predict ground movements due to construction. A database of London clay triaxial test data is presented. Use of a power model to predict strength mobilization is demonstrated for 17 previously published triaxial tests on high quality cores of London clay. A novel method of normalising these mobilization curves is demonstrated (using a reference strain at 50% mobilization of shear strength) different relations are shown to apply to different magnitudes of strain. The parameters that influence the variation of the reference strain are studied.
Petrographic and textural characteristics and mechanical behaviour of Sicilian calcarenites
Authors: Zimbardo M.  , Nocilla N.  , Ercoli L.
Published: February 2025

This study reports about the correlation between the petrographic and textural characteristics of some Sicilian calcarenites of Quaternary age and their mechanical behaviour. The composition and the texture of the different lithotypes are analysed by means of optical microscopy. The pores texture is the basis of the proposed classification. Laboratory tests are carried out for the determination of physical properties such as porosity; the mechanical behaviour is assessed by isotropic tests. Results indicate that the type and the distribution of the pores between the grains greatly influence the mechanical behaviour, specifically at the onset of yielding.
A soft-rock model for cement-improved clays
Authors: Arroyo M.  , Ciantia M.  , Castellanza R.  , Gens A.
Published: February 2025

Soil improvement techniques commonly result on soft clays mixed “in situ” with cement. Engineering practice has usually dealt with the treated soil bodies using simplistic constitutive models (e.g. elastic perfectly plastic Mohr Coulomb). A more refined bonded elasto-plastic model is here applied, emphasizing ease of calibration. Empirical studies have identified the ratio of cement content to the cured mixture void ratio as a controlling variable for mechanical response. This observation is elaborated upon to show that measuring porosity and unconfined compressive strength is enough to initialize the state variables of a bonded elasto-plastic model. The model is shown to predict the brittle behaviour of Bangkok clay-cement mixtures in oedoemeter tests. The relations here explored facilitate the use of more realistic soil models in the design of clay-cement structures.
Modelling the soil-water characteristic curve of structured and recomposed hard soils – weak rocks
Authors: Sitarenios P.  , Bardanis M.  , Kavvadas M.
Published: February 2025

The soil-water characteristic curve plays the major role in describing both the hydraulic and mechanical behaviour of unsaturated soils. In the present study the Fredlund and Xing and van Genuchten equations have been used to model the soil-water characteristic curves of typical Greek soils including three hard soils - weak rocks. It is attempted to correlate the optimum curve fitting parameters with physical characteristics of the soils and compare parameters of soil-water characteristic curves of undisturbed and recomposed soils.
Experimentally observed settlements beneath shallow foundations on sand
Authors: McMahon B.T.  , Bolton M.D.
Published: February 2025

Shallow foundations are designed by geotechnical engineers on a daily basis. Settlements are predicted based on elastic propertiesof soil. Soil is, however, non-linear even at small strains. A method was developed for testing circular shallow foundations on sand in the beam centrifuge at Cambridge University. The problem of bedding errors due to an uneven sand surface had to be overcome. Digital images were captured during the loading of soil bodies to observe deformation mechanisms. Instrumentation was used to confirm various quantities. Mechanisms and strain plots have been presented along with a comparison between settlements observed and a trial prediction based on the concepts of Mobilizable Strength Design (MSD).
Protection of the Cement Plant facilities foundations on the artificial firm soil base effected by dynamic loading (Autonomous Republic of Crimea, Ukraine)
Authors: Rozenvasser G.R.  , Tokovenko V.N.  , Zhigarev V.E.  , Malikov S.V.  , Symonovych V.E.
Published: February 2025

It contains the strategy of foundation arrangement on the artificial firm foundation soil base effected by dynamic loading due to the Site earthquake activity. The measures implemented ensure adequate foundation-base interaction as well as geotechnical and structural safety along with reduction of the seismic loading for the facilities (in particular, pre-heater) by no less than 1 point.
Base resistance of large diameter bored piles in soft rocks
Authors: Omer J.R.
Published: February 2025

Instrumented pile tests are analysed in order to study the mobilisation of base resistance of bored cast in-place piles in weak rocks. Also analysed are the relevant geotechnical data comprising tri-axial, unconfined compression, standard penetration and point load tests. Measured base resistances are compared with theoretical calculations utilising four approaches: (i) undrained, (ii) drained, (iii) hybrid approach and (iv) empirical correlation using in-situ soil test data. It is found that the development of base resistance is influenced by the following factors: (a) the degree of weathering and stiffness of the underlying soft rock, (b) the thickness and compressibility of any soil fragments existing beneath the pile base, and (c) the type of pile test and the rate of loading. Furthermore, the existence of compressible debris beneath a pile base results in a considerable reduction of the contribution of base resistance to the total pile head capacity. The mobilisation of maximum pile head resistance in weak rocks requires a substantial amount of settlement, which is typically 10%-20% of the pile diameter, but may be as high as 30% in the case of a pile base resting on soil debris. Based on the database analysed, a numerical model is developed for potential use in predicting the percentage composition of total head capacity in terms of shaft and base components. To allow practical application in pile design, the numerical model is formulated in terms of basic soil parameters which can be interpreted from the results of a conventional site investigation programme.
Heave of a piled foundation on a sulphated claystone
Authors: Ramon A.  , Alonso E.E.
Published: February 2025

A railway bridge founded on massive large diameter piles, socketed into hard anhydritic claystone, experienced a significant heave after construction. Field investigations revealed the presence of a swelling active layer below the piles tip. Heave was explained by the growth of gypsum crystals in discontinuities, a consequence of a previous dissolution of anhydrite. Percolating water to initiate the process was probably supplied by an upper aquifer which was connected with the underlying fractured claystone through borings and the piles themselves.
Capacity of rock sockets in weak mud/siltstone
Authors: Steenfelt J.S.  , Abild J.
Published: February 2025

Ruwais Sulphur Expansion Phase III in Abu Dhabi is part of a multi-billion dollars investment in Ruwais Industrial Complex. To meet the increased sulphur export demand the existing loading facility was expanded. The marine facilities consist of a quadrant beam and a pivot foundation for the ship loader, four mooring and four breasting dolphins. All structural elements are founded on raking steel piles rock socketed into the weak mudstone/siltstone bedrock. The paper describes the design of the piles (Ø762, 914 and 1067 mm) and in particular the pile load test set-up and the inferences from the load testing. It is concluded that the rock socket capacity is well over predictions by current design methods and it is demonstrated that the recommended tension pull out capacity referring to ground anchor design is extremely conservative.
Numerical Back-Analysis of compaction grouting with a hypoplastic soil model
Authors: Anthogalidis A.  , Arslan U.  , Reul O.
Published: February 2025

Compaction grouting is a well established ground improvement technique, which is mainly based on empirical data. Analytical and numerical models are not widely used in engineering practice yet. To develop the numerical modelling of compaction grouting, a back-analysis of a laboratory test was performed. A finite element model of compaction grouting was developed. It was possible to simulate the deformations measured in the laboratory tests with sufficient accuracy. The variable stress-strain behaviour of the soil-sample due to the progressive compaction was described with hypoplasticity by Kolymbas [11], extended by von Wolffersdorff [13].
Soil mix: influence of soil inclusions on structural behaviour
Authors: Ganne P.  , Denies N.  , Huybrechts N.  , Vervoort A.  , Tavallali A.  , Maertens J.  , Lameire B.  , De Cock F.
Published: February 2025

This paper first describes the soil mix procedures applied in Belgium. Then, it concentrates on the influence of soil inclusions (un-mixed materials) on the soil mix structural behaviour. Methodologies describing and quantifying inclusions are presented and applied on in situ executed soil mix materials from 18 sites in Belgium. Finally, first results of numerical simulations investigating the influence of soil inclusions on the stiffness of soil mix material are discussed.
Problems caused by the presence of hard concretions and lithified beds in the subsoil on the realisation of geotechnical investigations and infrastructure projects
Authors: van Alboom G.  , Vergauwen I.  , Maertens J.  , Maekelberg W.
Published: February 2025

The presence of hard concretions and lithified beds in the subsoil can cause serious problems during the realisation of infrastructure projects. As these concretions do most often not occur as continuous layers, they also are a real challenge for geotechnical investigations. This paper gives an overview of geological features and general characteristics of typical hard soil concretions in Flanders. Special attentions is paid to the important interaction between geology and geotechnics. Some typical examples are given of successful and unsuccessful geotechnical investigation programs and their effects on the realisation of infrastructure projects.
Interaction sol-structure: comparaison entre un renforcement de sol par Colonnes à Module Mixte CMM®et par Inclusions Rigides INSER®
Authors: Lambert S.  , Wehr W.  , Bustamante M.
Published: February 2025

Les Colonnes à Module Mixte CMM®sont une technique de renforcement de sol qui se développe de plus en plus en Europe. Elles sont constituées d'une inclusion rigide surmontée d'une tête en gravier refoulée réalisée selon le procédé de la colonne ballastée. Il apparaît que ce procédé permet d'augmenter la portance et de réduire significativement les tassements par rapport au sol en place avant renforcement tout en générant une interaction faible voire négligeable sur le dimensionnement des fondations et notamment des dallages. L'étude du comportement des Colonnes à Module Mixte CMM®se base sur des essais de chargement en vraie grandeur réalisés sur des colonnes isolées ou en groupe.
The influence of the ground's morphology on the seismic analysis with no integration errors
Authors: Manoli D.M.
Published: February 2025

In order to find the influence of ground's morphology three models are used. One of the simplest models for simulating the soil stress-strain response during earthquake loading is the viscoelastic Kelvin-Voigt model. The first model is using a horizontal surface and for the other two models a circular shape was added or removed from the regular surface in order to generate imperfections to the concave or convex surface. After the first run integration errors are found and the results are shown in the paper. After analyzing the obtained results it the different between the models is clarified.
Design and setup of a 2 meter high fully instrumented column for the analysis of the static and dynamic behaviour of hydraulic fills
Authors: Dávila M.
Published: February 2025

There exists a wide research on the characterization of the hydraulic fills in terms of either static or dynamic behaviour. However, it tends to be more difficult to find reported comprehensive analysis into these soils. Moreover, the semi-empirical procedures for evaluating the silo effect on cells in floating caissons, and the liquefaction potential of these soils during earthquakes are based on studies where the underlying influence parameters are not well known, yielding results with significant scatter. The project consists, therefore, of the design of a fully instrumented column, simulating conditions of hydraulic fills, in order to obtain a comprehensive characterization of the soil (i.e., density profiles, total and excess pore pressure, strength and stress-strain characterization, etc). This will provide with a better understanding of several phenomena such as the gradient in lateral pressures, the silo effect and the dynamic response of the soil.
Challenges of quick clay excavation in urban area with sloping ground
Authors: Nalbant R.M.
Published: February 2025

The paper presents the overall stability evaluation for a deep excavation in quick clay supported by flexible retaining structure (sheet pile wall) and ground improvement by lime-cement columns and vertical drains. The soil structure interaction analysis is performed using the finite element program Plaxis. The challenge of modelling the sloping layers with shear strength increasing linearly with depth is managed by using a special “vertical clusters” technique. Main conclusions from Plaxis analyses are as follows: Mohr-Coulomb model can be used to simulate pre-peak behavior of quick clay and the FE method can detect most critical failure mechanisms. The working sequences are monitored by lateral displacement (inclinometers), settlement and pore-water pressure measurements. Unfortunately, due to some site problems the quality of measurements is questionable. Despite some technical problems during the excavation work, the bottom of the excavation is now successfully closed by a concrete bottom slab and the structural work is in progress.
Changes of pore size and of hydraulic conductivity by adding lime in compacting clay liners
Authors: Metelková Z.  , Boháč J.  , Sedlářová I.  , Přikryl R.
Published: February 2025

The paper presents results of a laboratory study on the compacted mixture of clayey silt with 1–8% of CaO. Adding of CaO increased the maximum dry density and decreased the optimum water content. In the case of 4–8 % of added CaO the size of the pores kept decreasing until 360 of curing days, while with 2% of CaO the decrease stopped at 120 days and no further pore size changes were detected with 1% of added CaO after 28 curing days. The hydraulic conductivity of the treated soil increased from ca 10−9ms−1to 10−7ms−1on adding CaO, but then decreased back to the order of 10−9ms−1during several days of carrying out the permeability tests. At pH higher than 11.7 the pozzolanic reaction occurred and the soil voids changed due to the new mineral phases, hydrated calcium aluminates especially.
Albanian Design Practice of pile foundation compared to other international practices
Authors: Myftaraga E.  , Koreta O.
Published: February 2025

The calculation of the axial bearing capacity for pile foundations vary widely from one country to another, depending on the methods that each country use or on the building codes that has adapted in the legislation. In Albania, a legislation nor a building code exist for this purpose, but during years a design practice for pile foundations is consolidated. In this paper the calculation of the axial bearing capacity of a pile using Albanian Design Practice is shown in comparison with 3 other methods, which are: analytical method based on SPT data; analytical method based on CPTu data; method based on Japanese Design Practice. In order to have a satisfactory comparison between the results of the used methods, the calculations are carried out for both driven and cast-in-place piles, considering for each case several values for pile length and diameter. Analysis of the complete results enables to compare the method described in Albanian Design Practice with other proposed methods. The calculated bearing capacities show that the differences between the methods are apparent.
Manufacturing Considerations within Conceptual and Preliminary Aircraft Design
Authors: Fanthorpe C.  , Soban D.  , Price M.  , Butterfield J.
Published: February 2025

In attempt to reduce project cost and time overruns, evaluation of the product design process has become a key focus. Through the introduction of Value Engineering a paradigm shift has resulted whereby designers seek the most economically viable design, rather than strictly following customer requirements; which in past practices often resulted in expensive, inefficient product solutions. As systems become more complex vast quantities of information throughout the product development cycle is generated for analysis. Although analysis and control of the data presents an issue there are two main uses for the information. Opportunities exist where; more accurate flexible design solutions can be produced and application of Visual Analytics practises allow for a more user defined analysis as opposed to generic automatic data analysis and presentation. This paper will introduce the development of an innovative concept that will advance theories developed in Systems Engineering and Value-Driven Design. The concept will utilise regulatory and manufacturing information, to produce an optimised set of design solutions. The paper will perform an objective assessment of current engineering design practices, identify the benefit of using manufacturing and regulatory information in the design phase and identify a method through which the concept can be unified into a functional design environment.
Defining a Research Agenda in Value Driven Design: Questions That Need to be Asked
Authors: Soban Danielle S.  , Hollingsworth Peter  , Price Mark A.
Published: February 2025

Value driven design is an innovative design process that utilizes the optimization of a system level value function to determine the best possible design. This contrasts with more traditional systems engineering techniques, which rely on satisfying requirements to determine the design solution. While ‘design for value’ is intuitively acceptable, the transformation of value driven design concepts into practical tools and methods for its application is challenging. This, coupled with the growing popularity of value-centric design philosophies, has led to a proposed research agenda in value driven design. This research agenda asks fundamental questions about the design philosophy and attempts to identify areas of significant challenge. The research agenda is meant to stimulate discussion in the field, as well as prompt research that will lead to the development of tools and methodologies that will facilitate the application of value driven design and further the state of the art.
Variation of stiffness of Tehran coarse-grained soil with depth and strain
Authors: Sangtarashha K.  , Fakher A.  , Pahlevan B.
Published: February 2025

A remarkable zone of Tehran, capital of Iran, is composed of coarse-grained and cemented soils. These deposits mostly comprise gravel in company with variable amount of cobble and sand in addition to silt and clay. The style of stiffness variation of these kinds of soils versus confining pressure (depth) and strain has been studied in previous researches less often. To determine the form in which Tehran stiffness changes with depth and strain, Pressuremeter and shear wave velocity tests have been performed in this study. The results show that the stiffness of Tehran soil in small strains is considerably higher than stiffness of most gravelly soils reported in technical literature. A unique trend was observed in increase of soil stiffness with depth or confining pressure at several points of Tehran. Nonlinear stiffness reduction of A and C alluvium sediments of Tehran cannot be presented by Fahey-Carter model appropriately. By review of other coarse-grained soils stiffness, it was observed that the behavior of gravelly soils with high percentage of gravel, over consolidated coarse-grained soils, pre-strained coarse-grained soils and cemented soils are similar to Tehran soil. The specific behavior of Tehran soil and its dissimilarity to other coarse-grained soils is relevant to its cementation and over consolidation. The stiffness reduction curves of mentioned soils that were contradicting with Fahey-Carter model were compared with Ramberg-Ozgood model and observed that Ramberg-Ozgood model has a high capability of modeling nonlinear behavior of these kinds of soils. By combination of Fahey-Carter model and Ramberg-Ozgood model, a new model has been proposed which can present all possible stiffness reduction curves of coarse-grained soils in G/Gmax– τ/τmaxspace appropriately. Moreover, physical concepts have been presented for the new model parameters and their relevance to different variables has been determined.
Desiccation Cracks in Saturated Fine-Grained Soils
Authors: Shin Hosung  , Santamarina J.C.
Published: February 2025

The formation of desiccation cracks in clay has been understood based on tensile strength. However, this mechanistic model disregards the cohesionless, effective stress dependent frictional behavior of fine grained soils. We suggest an alternative theory using analyses, numerical simulations based on an effective stress formulation, and experiments monitored using high resolution time lapsed photography. New hypothesis assumes that desiccation cracks initiate as the air-water interface invades the saturated medium, driven by the increase in suction. Thereafter, the interfacial membrane causes an increase in the local void ratio at the tip, the air-entry value decreases, the air-water interface advances into the tip, and the crack grows. The effective stress remains compressive everywhere in the soil mass including at the tip of the desiccation crack.
Evaluation of the Intergranular Coefficient of Friction Using Discrete Element Modeling
Authors: Esidir Y.  , Cinicioglu O.
Published: February 2025

The shear strength of soil is generally expressed using macro-scale parameters, namely internal friction angle and cohesion. However this macro behavior is the resultant of both the dauntingly high number of intergranular interactions and the granular properties that control the mechanism of these interactions in the microscopic scale, such as granular size, shape, and surface texture. The aim of this study is to propose a method to obtain the intergranular coefficient of friction that is required for the discrete element modeling of soil problems. The behavior of granular materials under shear is dependent on the properties of individual grains that are interacting with each other. Discrete element method considers these individual interactions relying on the principles of mechanics and the computational power of modern computers. Therefore, computer simulations of the soil mechanics laboratory experiments using discrete element programs such as PFC2D will give a better understanding of phenomena at the particulate level. Within this context, different uniform sand samples are investigated according to their shape properties and angle of repose tests are done in order to find their frictional characteristics. Angle of repose tests are numerically modeled using discrete element modeling method. These models reflect the surface shape and interparticle friction coefficient of sand grains. Accordingly, in order to obtain the model-appropriate value of the interparticle coefficient of friction, experimental and numerical results are compared and the results are reported and discussed.
Two-dimensional Axisymmetric nonlinear finite strain consolidation for reclaimed dredged material
Authors: Ahn Yonghoon  , Kwak Taehoon  , Min Sunhong  , Lim Jeehee  , Choi Hangseok
Published: February 2025

Estimation for time rate consolidation of dredged deposits is considerably complicated when vertical drains are installed to enhance consolidation process of such a soft soil stratum because the vertical drains are commonly installed before self-weight consolidation is ceased. In this paper, two new methods have been proposed to take into account both vertical and radial drainage conditions during nonlinear finite strain self-weight consolidation of dredged soil deposits. That is the approaches are proposed to predict the self-weight consolidation behavior considering the vertical drain. For one-dimensional nonlinear finite strain consolidation in the vertical direction, the simplified Morris's analytical solution (2002) and the PSDDF analysis are adopted. On the other hand, to consider the radial drainage, the Barron's vertical drain theory (1948) is used. The overall average degree of self-weight consolidation of the dredged soil is estimated using the Carillo's formula (1942), in which both vertical and radial drainage are considered. A series of large-scale self-weight consolidation experiments being equipped with a vertical drain has been carried out to verify the analysis method proposed in this paper. The results of the new analysis methods are generally in agreement with those of the experiments.
A Numerical Evaluation of a Cover Embankment Model on Very Soft Halic Dredge Material
Authors: Terzi N. Ugur  , Selcuk M. Ergenekon  , Sengul T.
Published: February 2025

The objective of this study is to evaluate the consolidation process and long-term deformation behavior of an embankment constructed on dredge material from the Halic (know as Golden Horn) in Istanbul. A comprehensive laboratory studies were performed on dredge material and with using the laboratory test results, finite element numerical method was carried out to analyze the embankment construction procedure, and its relationship with the Halic dredge materials. The Soft Soil Creep Model for very soft dredge material and the Mohr-Coulomb Soil Model for embankment material was utilized in the numerical investigations. For the numerical analysis, engineering and consolidation characteristics of the Halic dredge material were determined by using in-situ and laboratory tests. The results proved that the chosen Soft Soil Model and Mohr-Coulomb for the Halic dredge and embankment materials are efficient in assessing the geotechnical behavior and the long term pore water pressure dissipation of the embankment-foundation system model.
The Evaluation of Field Application for Geophysical Survey on Levee
Authors: Kim Jin-Man  , Choi Bong-Hyuck  , Kim Kyung-Min  , Do Jong-Nam  , Chun Byung-Sik
Published: February 2025

Cases of applying geophysical survey investigations such as self-potential prospecting survey, electrical resistivity survey and geothermal survey to evaluate wholesomeness of levee structures or detecting levee' leakage areas are increasing, but such cases are currently restricted to simple applications of geophysical survey technology that assume 2-dimensional structure types. Also, domestic researches that are directly related to the diagnosis of the levee's safety through application of underground radar that has the highest resolution among geophysical surveys is almost non-existent, and cases of applying ground penetrating radar (GPR) survey to the joint investigation of the tunnel lining's rear have been reported. Therefore, this study attempted to effectively comprehend the safety of the levee's basic structures and drainage box-culvert by utilizing 2-dimensional electrical resistivity surveys, expansion of 3-dimensional survey path and GPR surveys.
Consolidation Characteristics and PBD Application in Deep Soft Ground
Authors: Lee Jong-hwi  , Byun Yo-seph  , Ahn Byung-je  , Chun Byung-sik
Published: February 2025

Various ground improvement methods were applied to obtain the preceding settlement of the soft ground and strength increase and the vertical drain method has been used to reduce the required time for consolidation of the soft ground. Especially, the plastic board drain (PBD) has been widely used among the vertical drain method. In this study, the behavior of characteristics was evaluated by operating a compound drainage capacity test, a smear zone test about the plastic board drain (PBD) method applied in soft clay in deep depth. Also, the scanning electron microscopy (SEM) was then taken cutting the filter section of the PBD. From result of the tests, it was found that change of settlement through load steps resulted from dissipation of pore pressure and it was also found that the drainage capacity of vertical drains was considerably reduced with pressure increase and time elapse. In the case of SEM, it showed that clay particles were stacked outside of the PBD but almost no clay particles were stacked inside of the PDB. In the case of the double core PBD, fine-grained soil was not observed with the naked eye when the test was performed.
Proposal for improvement of the pressuremeter settlement prediction method of shallow foundations in sand
Authors: Maragkos Nikolaos  , Maragkos Athanasios  , Marangos Christos
Published: February 2025

Load tests on a rigid strip footing embedded in sand compacted to six different densities are used to investigate the accuracy of the pressuremeter settlement prediction method of shallow foundations. The results indicate that in settlement prediction studies, distinction between dense and loose sands should be made; the pressuremeter method should be corrected using correction factors which are dependent on load level and are different for dense and loose sands.
Diaphragm wall movements associated with the construction of a deep basement in Seoul Korea
Authors: Davies J.A.  , Lam A.K.  , Chang H.S.  , Junaideen S.M.
Published: February 2025

A major commercial development in the heart of Seoul required the excavation of a basement over 38 metres deep. The geology consisted of over 20 metres of alluvial deposits overlying variably weathered bedrock. The perimeter wall was constructed adopting diaphragm walls and the temporary lateral support provided by over 3000 temporary ground anchors. The design was initially carried out adopting a Mohr Coulomb soil model and the field observations of wall and ground movements were comparable to the design predictions. The results were then compared with predictions using a soil hardening model and conclusions drawn on an appropriate simple Mohr Coulomb that could be adopted for routine design.
Using centrifuge models to define deformation mechanisms and generate design methods
Authors: Bolton M.D.
Published: February 2025

The analysis of comparative digital photographs by Particle Image Velocimetry (PIV) offers a powerful technique for the demonstration of deformation mechanisms in soil models. Where small-scale models can be tested in a geotechnical centrifuge at a sufficiently uniform acceleration to broadly recreate full-scale stresses, it will follow that soil stiffness and strength will equally be appropriate to the full scale. If sufficient attention has been paid to the creation of appropriate boundary conditions, and to the actuation of a representative construction and loading sequence, the observed mechanism can be used to deduce the characteristic features of similar processes in the field. This requires a further step of simplification and mathematical characterization. Any recommendation for the use of such a mechanism in design should depend on a consistency check of the conservation of energy in the model, leading to sufficiently accurate predictions at model scale. Such a demonstration is consistent with the Mobilizable Strength Design (MSD) method which has been shown to serve as an efficient means of predicting and controlling ground deformations. Examples will be given of the behavior of tunnels, deep excavations and slopes.
Indication of Clay Structure Restoration in Laboratory Testing Using Bender Element Measurements
Authors: Guldur B.  , Sheahan T.C.
Published: February 2025

For soft soils, sampling methods, specimen preparation and subsequent test results are all affected by the degree of soil structure and level of destructuration occurring during these phases. Consolidation has been shown to be a primary means for restoring a soft soil's structure, or an approximation of that structure. The amount of this restoration can be quantified by comparing the measured shear wave velocity values before and after various test phases. Shear waves can be generated and received by bender elements that are composed of piezoceramic plates. When bender elements are inserted into a triaxial testing system, they provide non-destructive testing during an ongoing triaxial test. In this research, bender elements are implemented in an automated triaxial apparatus using methods developed by Landon (2004). Two different soil types, one sampled using conventional tube sampling and one using Sherbrooke-type block sampling, were tested to assess how reconsolidation affects the structure of the soil, by comparing bender element data. A MatLab® based program was used to actuate the excitation of benders, and to measure and analyze the resulting shear wave transmission. By comparing shear wave velocity results at various stages of the test, the change in the soil structure as a result of those test stages can be inferred. The results show that, based on bender element shear wave velocity measurements, the back pressure and consolidation phases help to restore the shear wave velocity values and the shearing phase only marginally degrades the structure, even at relatively high, end-of-shear strains.
Deformation and Strength Characteristics of Gypsum-mixed Decomposed Granite Soil
Authors: Torii N.  , Kawajiri S  , Shibuya S.  , Takeuchi M.  , Araki S.
Published: February 2025

In order to prevent and mitigate disasters due to slope failure, it is important to evaluate the likelihood of slope failure quantitatively by considering the soil properties. It is known that the residual decomposed granite soil on slope has an interparticle skeletal structure. Therefore, in order to examine the deformation and strength characteristics, it is necessary to evaluate the effects of the interparticle skeletal structure by using a completely undisturbed sample in the laboratory. However, it is not easy to procure such a perfect sample due to the difficulty of sampling, for instance. In this study, in order to examine the effect of the interparticle skeletal structure of residual granite soil on the deformation and strength characteristics, consolidation test with bender elements, constant pressure direct box shear test and unconfined compression test were performed using gypsum-mixed decomposed granite soil specimens in which the mechanical characteristics of undisturbed decomposed granite soil specimen were simulated. The test results suggest that the interparticle skeletal structure of residual decomposed granite soil has a considerable influence on the deformation and strength characteristics under the conditions of low confining pressure in which the slope failure often occurs.