for Journals by Title or ISSN for Articles by Keywords help

Publisher: Springer-Verlag (Total: 2353 journals)

 Acta Geotechnica   [SJR: 1.818]   [H-I: 22]   [7 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1861-1133 - ISSN (Online) 1861-1125    Published by Springer-Verlag  [2353 journals]
• Stress–strain behavior of cement-improved clays: testing and
modeling
• Authors: Allison J. Quiroga; Zachary M. Thompson; Kanthasamy K. Muraleetharan; Gerald A. Miller; Amy B. Cerato
Pages: 1003 - 1020
Abstract: Abstract The results of a series of laboratory tests on unimproved and cement-improved specimens of two clays are presented, and the ability of a bounding surface elastoplastic constitutive model to predict the observed behavior is investigated. The results of the oedometer, triaxial compression, extension, and cyclic shear tests demonstrated that the unimproved soil behavior is similar to that of soft clays. Cement-improved specimens exhibited peak/residual behavior and dilation, as well as higher strength and stiffness over unimproved samples in triaxial compression. Two methods of accounting for the artificial overconsolidation effect created by cement improvement are detailed. The apparent preconsolidation pressure method is considerably easier to use, but the fitted OCR method gave better results over varied levels of confining stresses. While the bounding surface model predicted the monotonic behavior of unimproved soil very well, the predictions made for cyclic behavior and for improved soils were only of limited success.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0529-1
Issue No: Vol. 12, No. 5 (2017)

• Field testing of one-way and two-way cyclic lateral responses of single
and jet-grouting reinforced piles in soft clay
• Authors: Ben He; Lizhong Wang; Yi Hong
Pages: 1021 - 1034
PubDate: 2017-10-01
DOI: 10.1007/s11440-016-0515-z
Issue No: Vol. 12, No. 5 (2017)

• Pile reinforcement mechanism of soil slopes
• Authors: Ga Zhang; Liping Wang; Yaliang Wang
Pages: 1035 - 1046
Abstract: Abstract Stabilizing piles are widely used as an effective and economic reinforcement approach for slopes. Reasonable designs of pile reinforcement depend on the understanding of reinforcement mechanism of slopes. A series of centrifuge model tests were conducted on the pile-reinforced slopes and corresponding unreinforced slopes under self-weight and vertical loading conditions. The deformation of the slope was measured using image-based analysis and employed to investigate the pile reinforcement mechanism. The test results showed that the piles significantly reduced the deformation and changed the deformation distribution of the slope, and prevented the failure occurred in the unreinforced slope. The pile influence zone was determined according to the inflection points on the distribution curves of horizontal displacement, which comprehensively described the features of the pile–slope interaction and the characteristics of reinforced slopes. The concepts of anti-shear effect and compression effect were proposed to quantitatively describe the restriction features of the piles on the deformation of the slope, namely the reduction in the shear deformation and the increase in the compression deformation, respectively. The pile reinforcement effect mainly occurred in the pile influence zone and decreased with increasing distance from the piles. There was a dominated compression effect in the vicinities of the piles. The compression effect developed upwards in the slope with a transmission to the anti-shear effect. The anti-shear effect became significantly dominated near the slip surface and prevented the failure that occurred in the unreinforced slope.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0543-3
Issue No: Vol. 12, No. 5 (2017)

• Numerical simulations of the reuse of piled raft foundations in clay
• Authors: Brian Sheil
Pages: 1047 - 1059
Abstract: Abstract The development and growth of urban environments in recent years is requiring geotechnical engineers to consider foundation reuse as a more sustainable solution to inner city redevelopment. Two main phenomena associated with foundation reuse have been reported in the literature, namely ‘preloading effects’ and ‘ageing effects’. The aim of this paper is to investigate the relative merits of these effects on the reusability of both piled and unpiled raft foundations in clay. Finite element analysis, in conjunction with an isotropic elasto-viscoplastic soil model, is employed for this purpose. The study is presented in two phases: (1) evaluation of preloading effects only by using a very low creep coefficient and (2) evaluation of combined preloading and creep effects. The variables considered in the parametric study include the number of piles, pile spacing, pile length, and soil type. Results show that both unpiled and piled rafts can exhibit significant capacity and stiffness increases upon reloading even for moderate levels of preload. Moreover, these increases are strongly dependent on the piled raft load sharing where unpiled raft and free-standing pile group capacity gains serve as upper and lower bounds, respectively, for that of a piled raft. This study underlines foundations reuse as an effective and sustainable solution for inner city redevelopment.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0522-8
Issue No: Vol. 12, No. 5 (2017)

• Testing and modeling the behavior of pre-bored grouting planted piles
under compression and tension
• Authors: Jia-jin Zhou; Xiao-nan Gong; Kui-hua Wang; Ri-hong Zhang; Jia-jia Yan
Pages: 1061 - 1075
Abstract: Abstract A group of field tests and three-dimensional finite element simulation were used to investigate the behavior of the pre-bored grouting planted pile under compression and tension; moreover, a group of shear tests of the concrete–cemented soil interface was carried out to study the frictional capacity of the pile–cemented soil interface. The load–displacement response, shaft resistance and mobilized base load were discussed based on the measured and computed results. The measured and computed results show that the frictional capacity of the cemented soil–soil interface is better than the frictional capacity of the concrete–soil interface. The frictional capacity of the concrete–cemented soil interface is mainly controlled by the properties of the cemented soil, and the ultimate skin friction of the concrete–cemented soil interface is much larger than that of the cemented soil–soil interface. The frictional capacity of the soil layer close to the enlarged base is also promoted because of the compaction of the enlarged base. The enlarged cemented soil base can promote the behavior of the pile foundation under tension, and the enlarged cemented soil base undertakes approximately 26.3% of the total uplift load under the ultimate bearing capacity in this research.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0540-6
Issue No: Vol. 12, No. 5 (2017)

• Vertical bearing capacity behaviour of single T-shaped soil–cement
column in soft ground: laboratory modelling, field test, and calculation
• Authors: Yaolin Yi; Songyu Liu; Anand J. Puppala; Peisheng Xi
Pages: 1077 - 1088
Abstract: Abstract The T-shaped soil–cement column is a variable-diameter column, which has an enlarged column cap at the shallow depth, resulting in the column shape being analogous to the letter “T”. In this study, 1-g laboratory and full-scale field loading tests were employed to investigate the vertical bearing capacity behaviour of a single T-shaped column in soft ground. Pressure cells were set in a T-shaped column in the field to measure the vertical column stress above and below the column cap during the loading test. After the loading test, several columns were excavated to investigate their failure modes. The results indicated that, since the section area of the column cap was remarkably higher than that of the deep-depth column, the stress concentration occurred in the deep-depth column just under the cap, leading to column failure. Based on this failure mode, a simplified method was proposed to estimate the ultimate bearing capacity of a single T-shaped column; the comparison of estimated and measured results indicated the applicability of the proposed method.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0555-z
Issue No: Vol. 12, No. 5 (2017)

• Failure modes and bearing capacity of strip footings on soft ground
reinforced by floating stone columns
• Authors: Haizuo Zhou; Yu Diao; Gang Zheng; Jie Han; Rui Jia
Pages: 1089 - 1103
Abstract: Abstract This study evaluates the failure modes and the bearing capacity of soft ground reinforced by a group of floating stone columns. A finite difference method was adopted to analyze the performance of reinforced ground under strip footings subjected to a vertical load. The investigation was carried out by varying the aspect ratio of the reinforced zone, the area replacement ratio, and the surface surcharge. General shear failure of the reinforced ground was investigated numerically without the surcharge. The results show the existence of an effective length of the columns for the bearing capacity factors N c and N γ. When certain surcharge was applied, the failure mode of the reinforced ground changed from the general shear failure to the block failure. The aspect ratio of the reinforced zone and the area replacement ratio also contributed to this failure mode transition. A counterintuitive trend of the bearing capacity factor N q can be justified with a shift in the critical failure mode. An upper-bound limit method based on the general shear failure mode was presented, and the results agree well with those of the previous studies of reinforced ground. Equivalent properties based on the area-weighted average of the stone columns and clay parameters were used to convert the individual column model to an equivalent area model. The numerical model produced reasonable equivalent properties. Finally, a theoretical method based on the comparison of the analytical equations for different failure modes was developed for engineering design. Good agreement was found between the theoretical and numerical results for the critical failure mode and its corresponding bearing capacity factors.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0535-3
Issue No: Vol. 12, No. 5 (2017)

• Pressuremeter test parameters of a compacted illitic soil under thermal
cycling
• Authors: H. Eslami; S. Rosin-Paumier; A. Abdallah; F. Masrouri
Pages: 1105 - 1118
Abstract: Abstract The incorporation of heat exchangers in geostructures changes the temperature of the adjacent soil, raising important issues concerning the effect of temperature variations on hydro-mechanical soil behaviour. The objective of this paper is to improve the understanding and quantification of the impact of temperature variation on the bearing capacity of thermo-active piles. Currently, the design of deep foundations is based on the results of in situ penetrometer or pressuremeter tests. However, there are no published data on the effect of temperature on in situ soil parameters, preventing the specific assessment of the behaviour of thermo-active piles. In this study, an experimental device is developed to perform mini-pressuremeter tests under controlled laboratory conditions. Mini-pressuremeter tests are performed on an illitic soil in a thermo-regulated metre-scale container subjected to temperatures from 1 to 40 °C. The results reveal a slight decrease in the pressuremeter modulus (E p) and a significant decrease in the creep pressure (p f) and limit pressure (p l) with increasing temperature. The results also reveal the reversibility of this effect during a heating–cooling cycle throughout the investigated temperature range, whereas the effect of a cooling–heating cycle was only partially reversible. In the case of several thermal cycles, the effect of the first cycle on the soil parameters is decisive.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0552-2
Issue No: Vol. 12, No. 5 (2017)

• Advance in the penetrometer test formulation to estimate allowable
pressure in granular soils
• Authors: Jesús Díaz-Curiel; Sandra Rueda-Quintero; Bárbara Biosca; Georgina Doñate-Matilla
Pages: 1119 - 1127
Abstract: Abstract In this paper, we present a modification of the existing mathematical formulation used to obtain the allowable bearing pressure from dynamic penetration tests in order to extend its applicability to the design of shallow foundations. The conventional relationships adopted to obtain the allowable bearing pressure from penetrometer tests have a discontinuous gradient, and they are limited to a depth less than the footing width. The aim of this work was to find a relationship that permits the estimation of this pressure in cohesionless soils, from the results of dynamic probing super heavy tests, through a single non-piecewise and continuous relationship that remains valid up to depths several times the footing width. This equation was applied as part of the geomechanical characterization survey undertaken for the construction of an elevated helipad in the centre of the Iberian Peninsula. The survey results were considered satisfactory, and the construction was completed without structural problems.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0565-x
Issue No: Vol. 12, No. 5 (2017)

• Shear wave velocity as function of cone penetration resistance and grain
size for Holocene-age uncemented soils: a new perspective
• Authors: Mourad Karray; Mahmoud N. Hussien
Pages: 1129 - 1158
Abstract: Abstract For feasibility studies and preliminary design estimates, field measurements of shear wave velocity, V s, may not be economically adequate and empirical correlations between V s and more available penetration measurements such as cone penetration test, CPT, data turn out to be potentially valuable at least for initial evaluation of the small-strain stiffness of soils. These types of correlations between geophysical (Vs) and geotechnical (N-SPT, q c-CPT) measurements are also of utmost importance where a great precision in the calculation of the deposit response is required such as in liquefaction evaluation or earthquake ground response analyses. In this study, the stress-normalized shear wave velocity V s1 (in m/s) is defined as statistical functions of the normalized dimensionless resistance, Q tn-CPT, and the mean effective diameter, D 50 (in mm), using a data set of different uncemented soils of Holocene age accumulated at various sites in North America, Europe, and Asia. The V s1–Q tn data exhibit different trends with respect to grain sizes. For soils with mean grain size (D 50) < 0.2 mm, the V s1/Q tn 0.25 ratio undergoes a significant reduction with the increase in D 50 of the soil. This trend is completely reversed with further increase in D 50 (D 50 > 0.2 mm). These results corroborate earlier results that stressed the use of different CPT-based correlations with different soil types, and those emphasized the need to impose particle-size limits on the validity of the majority of available correlations.
PubDate: 2017-10-01
DOI: 10.1007/s11440-016-0520-2
Issue No: Vol. 12, No. 5 (2017)

• Seasonal effects on geophysical–geotechnical relationships and their
implications for electrical resistivity tomography monitoring of slopes
• Authors: R. M. Hen-Jones; P. N. Hughes; R. A. Stirling; S. Glendinning; J. E. Chambers; D. A. Gunn; Y. J. Cui
Pages: 1159 - 1173
Abstract: Abstract Current assessments of slope stability rely on point sensors, the results of which are often difficult to interpret, have relatively high costs and do not provide large-area coverage. A new system is under development, based on integrated geophysical–geotechnical sensors to monitor groundwater conditions via electrical resistivity tomography. So that this system can provide end users with reliable information, it is essential that the relationships between resistivity, shear strength, suction and water content are fully resolved, particularly where soils undergo significant cycles of drying and wetting, with associated soil fabric changes. This paper presents a study to establish these relationships for a remoulded clay taken from a test site in Northumberland, UK. A rigorous testing programme has been undertaken, integrating the results of multi-scalar laboratory and field experiments, comparing two-point and four-point resistivity testing methods. Shear strength and water content were investigated using standard methods, whilst a soil water retention curve was derived using a WP4 dewpoint potentiometer. To simulate seasonal effects, drying and wetting cycles were imposed on prepared soil specimens. Results indicated an inverse power relationship between resistivity and water content with limited hysteresis between drying and wetting cycles. Soil resistivity at lower water contents was, however, observed to increase with ongoing seasonal cycling. Linear hysteretic relationships were established between undrained shear strength and water content, principally affected by two mechanisms: soil fabric deterioration and soil suction loss between drying and wetting events. These trends were supported by images obtained from scanning electron microscopy.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0523-7
Issue No: Vol. 12, No. 5 (2017)

• Particle breakage and deformation of carbonate sands with wide range of
• Authors: Yang Xiao; Hanlong Liu; Qingsheng Chen; Qifeng Ma; Yuzhou Xiang; Yingren Zheng
Pages: 1177 - 1184
Abstract: Abstract In this technical note, evolutions of the particle size distribution, particle breakage, volume deformation and input work of carbonate sands with varying relative densities were investigated through performing a series of one-dimensional compression tests. Loading stress levels ranged from 0.1 to 3.2 MPa. It was found that the initial relative density could greatly affect the magnitude of particle size distribution, particle breakage, volume deformation and input work. Particularly, it was observed that the specimen at a lower relative density underwent much more particle breakage than that at a higher relative density. This could be attributed to the change of the coordination number with the initial density. However, a unique linear relationship between the particle breakage and input work per volume could be obtained, which is independent of the initial relative density.
PubDate: 2017-10-01
DOI: 10.1007/s11440-017-0580-y
Issue No: Vol. 12, No. 5 (2017)

• Monotonic and cyclic tests on kaolin: a database for the development,
calibration and verification of constitutive models for cohesive soils
• Authors: Torsten Wichtmann; Theodoros Triantafyllidis
Abstract: Abstract A database with about 60 undrained monotonic and cyclic triaxial tests on kaolin is presented. In the monotonic tests, the influences of consolidation pressure, overconsolidation ratio, displacement rate and sample cutting direction have been studied. In the cyclic tests, the stress amplitude, the initial stress ratio and the control (stress vs. strain cycles) have been additionally varied. Isotropic consolidation leads to a failure due to large strain amplitudes with eight-shaped effective stress paths in the final phase of the cyclic tests, while a failure due to an excessive accumulation of axial strain and lens-shaped effective stress paths was observed in the case of anisotropic consolidation with $$q^{\text{ ampl }}< q^{\text{ av }}$$ . The rate of pore pressure accumulation grew with increasing amplitude and void ratio (i.e. decreasing consolidation pressure and overconsolidation ratio). The “cyclic flow rule” well known for sand has been confirmed also for kaolin: With increasing value of the average stress ratio $$\eta ^{\text{ av }} = q^{\text{ av }} /p^{\text{ av }},$$ the accumulation of deviatoric strain becomes predominant over the accumulation of pore water pressure. The tests on the samples cut out either horizontally or vertically revealed a significant effect of anisotropy. In the cyclic tests, the two kinds of samples exhibited an opposite inclination of the effective stress path. Furthermore, the horizontal samples showed a higher stiffness and could sustain a much larger number of cycles to failure. All data of the present study are available from the homepage of the first author. They may serve for the examination, calibration or improvement in constitutive models dedicated to cohesive soils under cyclic loading, or for the development of new models.
PubDate: 2017-09-14
DOI: 10.1007/s11440-017-0588-3

• A hypo-plastic approach for evaluating railway ballast degradation
• Authors: Arghya Das; Prashant Kumar Bajpai
PubDate: 2017-09-14
DOI: 10.1007/s11440-017-0584-7

• Influence of cementation level on the strength behaviour of bio-cemented
sand
• Abstract: Abstract Microbially induced calcite precipitation (MICP) is used increasingly to improve the engineering properties of granular soils that are unsuitable for construction. This shows MICP technique significant advantages such as low energy consumption and environmentally friendly feature. The objective of the present study is to assess the strength behaviour of bio-cemented sand with varying cementation levels, and to provide an insight into the mechanism of MICP treatment. A series of isotropic consolidated undrained compression tests, calcite mass measurement and scanning electron microscopy tests were conducted. The experimental results show that the strength of bio-cemented sand depends heavily on the cementation level (or calcite content). The variations of strength parameters, i.e. effective friction angle φ′ and effective cohesion c′, with the increase in calcite content can be well evaluated by a linear function and an exponential function, respectively. Based on the precipitation mechanism of calcite crystals, bio-clogging and bio-cementation of calcite crystals are correlated to the amount of total calcite crystals and effective calcite crystals, respectively, and contributed to the improvement in the effective friction angle and effective cohesion of bio-cemented sand, separately.
PubDate: 2017-09-08
DOI: 10.1007/s11440-017-0574-9

• Characterization of microstructural and physical properties changes in
biocemented sand using 3D X-ray microtomography
• Abstract: Abstract An experimental study has been performed to investigate the effect of the biocalcification process on the microstructural and the physical properties of biocemented Fontainebleau sand samples. The microstructural properties (porosity, volume fraction of calcite, total specific surface area, specific surface area of calcite, etc.) and the physical properties (permeability, effective diffusion) of the biocemented samples were computed for the first time from 3D images with a high-resolution images obtained by X-ray synchrotron microtomography. The evolution of all these properties with respect to the volume fraction of calcite is analysed and compared with success to experimental data, when it is possible. In general, our results point out that all the properties are strongly affected by the biocalcification process. Finally, all these numerical results from 3D images and experimental data were compared to numerical values or analytical estimates computed on idealized microstructures constituted of periodic overlapping and random non-overlapping arrangements of coated spheres. These comparisons show that these simple microstructures are sufficient to capture and to predict the main evolution of both microstructural and physical properties of biocemented sands for the whole range of volume fraction of calcite investigated.
PubDate: 2017-09-08
DOI: 10.1007/s11440-017-0578-5

• Experimental characterization and 3D DEM simulation of bond breakages in
artificially cemented sands with different bond strengths when subjected
to triaxial shearing
• Authors: Z. Li; Y. H. Wang; C. H. Ma; C. M. B. Mok
Abstract: Abstract This paper describes the mechanical behavior of artificially cemented sands with strong, intermediate, and weak bond strengths, using experimentation and 3D discrete element method (DEM) simulation. The focus is on the features of bond breakage and the associated influences on the stress–strain responses. Under triaxial shearing, the acoustic emission rate captured in the experiment and the bond breakage rate recorded in the simulations show resemblance to the stress–strain response, especially for strongly and intermediately cemented samples, where a strain softening response is observed. The simulations further reveal the shear band formation coincides with the development of bond breakage locations due to the local weakness caused by the bond breakages. Strain softening and volumetric dilation are observed inside the shear band, while the region outside the shear band undergoes elastic unloading. The weakly cemented sample exhibits a strain hardening response instead; bond breakages and the associated local weaknesses are always randomly formed such that no persistent shear band is observed. Note that in the DEM simulation, the flexible membrane boundary is established by a network of bonded membrane particles; the membrane particle network is further partitioned into finite triangular elements. The associated algorithm can accurately distribute the applied confining pressure onto the membrane particles and determine the sample volume.
PubDate: 2017-08-18
DOI: 10.1007/s11440-017-0593-6

• Lulu Zhang, Jinhui Li, Xu Li, Jie Zhang, Hong Zhu: Rainfall-induced soil
slope failure: stability analysis and probabilistic assessment
• Authors: Wei Wu
PubDate: 2017-08-17
DOI: 10.1007/s11440-017-0591-8

• Reply to “Discussion of ‘Numerical limit analysis of three-dimensional
slope stability problems in catchment areas’ by Camargo et al.
(DOI:10.1007/s11440-016-0459-3)” by Ukritchon et al.
(DOI:10.1007/s11440-017-0589-2)
• Authors: Júlia Camargo; Raquel Quadros Velloso; Euripedes A. Vargas
PubDate: 2017-08-17
DOI: 10.1007/s11440-017-0590-9

• Discussion of “numerical limit analysis of three-dimensional slope
stability problems in catchment areas” by Camargo et al.
(doi:10.1007/s11440-016-0459-3)
• Authors: Boonchai Ukritchon; Suraparb Keawsawasvong
Abstract: Abstract A paper recently published by Camargo et al. (Acta Geotech 11(6):1369–1383, 2016) (hereafter identified as “the authors”) presented the numerical limit analysis method (NLA) to compute the safety factor and collapse mechanism of three-dimensional (3D) slopes. For NLA, the authors employed the discrete three-dimensional lower bound formulation with pore water pressure consideration and Drucker–Prager yield criterion, and cast a slope problem as a second-order conic programming problem. The developed program was implemented in MATLAB and validated through three examples of slope problems, and was applied to solve a large-scale 3D slope problem of a failure case study. The discussion of this article focuses on the formulation of the developed 3D NLA and static admissibility of stress field solutions obtained from NLA.
PubDate: 2017-08-16
DOI: 10.1007/s11440-017-0589-2

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327

Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs