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Fibre optic sensing for strain-field measurement in geotechnical laboratory experiments Géotech. Lett. (IF 2.1) Pub Date : 2023-11-16 G. Della Ragione, C. N. Abadie, X. Xu, T. S. da Silva Burke, T. Möller, E. Bilotta
Strain measurement inside the soil body in three-dimensional (3D) experiments is a real challenge for physical modellers in geotechnics. The use of fibre optic sensing offers the possibility of continuous measurement of the strain at depth with high spatial and temporal resolution in small-scale laboratory experiments. Despite the technology not being fully ready yet for centrifuge experiments, this
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Novel procedure for measuring the saturation of the pore-pressure system in piezocone tips Géotech. Lett. (IF 2.1) Pub Date : 2023-11-10 I. Rocchi, M. Marcolongo, L. Tonni, G. Gottardi
Uncertainty in the measurement of the cone penetration test with pore-water pressure measurement (i.e. piezocone testing CPTU) can be caused by an equipment malfunction, poor calibration and maintenance of sensors, but also by a lack of saturation of the piezocone. The standards allow for many different options in terms of filters, saturation fluids and methodologies. The novel device described herein
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Competing effects of wetting and volume change on G0 in compacted loess Géotech. Lett. (IF 2.1) Pub Date : 2023-11-09 M. Ge, J. Pineda, D. Sheng
This paper explores the relative contributions of wetting (suction reduction) and its associated volume change on the small-strain shear stiffness, G0, in compacted loess from Xi’an, China. Results from one-dimensional compression tests with measurements of the shear wave velocity upon wetting and loading paths are presented. The experimental results show that the softening caused by wetting compete
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A new grouting cable without a core tube used for reinforcement of fractured rock mass Géotech. Lett. (IF 2.1) Pub Date : 2023-10-13 Y. Kang, Y. Li, M. Zhang, X. Li, B. Liu
Grouting cable is a newly developed technology for the reinforcement of fractured rock mass in coal mines of China. It integrates the procedures of cable anchoring and grouting, thus simplifying the working procedure of roadway support. However, ordinary grouting cable products with a core tube have some significant defects, such as a narrow flow channel, difficulty in slurry diffusion and significant
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A novel procedure for measuring the saturation of the pore-pressure system in piezocone tips Géotech. Lett. (IF 2.1) Pub Date : 2023-10-16 I. Rocchi, M. Marcolongo, L. Tonni, G. Gottardi
Uncertainty in the measurement of the pore-water pressure in piezocone testing (CPTU) can be caused by an equipment malfunction, poor calibration and maintenance of sensors, but also by a lack of saturation of the piezocone. The standards allow for many different options in terms of filters, saturation fluids and methodologies. The novel device described herein aims at measuring in a very simple manner
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Small-strain, non-linear elastic Winkler model for uniaxial loading of suction caisson foundations Géotech. Lett. (IF 2.1) Pub Date : 2023-09-18 S. K. Suryasentana, H. J. Burd, B. W. Byrne, A. Shonberg
Soils exhibit non-linear stress-strain behaviour, even at relatively low strain levels. Existing Winkler models for suction caisson foundations cannot capture this small-strain, non-linear soil behaviour. To address this issue, this paper describes a new non-linear elastic Winkler model for the uniaxial loading of suction caissons. The soil reaction curves employed in the model are formulated as scaled
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Effects of ultrasonic oscillations on permeability of rocks during the paraffinic oil flow Géotech. Lett. (IF 2.1) Pub Date : 2023-08-17 E. Riabokon, E. Gladkikh, M. Turbakov, E. Kozhevnikov, M. Guzev, N. Popov, P. Kamenev
The paper shows that depending on the degree of blockage of the pore space due to paraffin precipitation the ultrasonic treatment has different effects. If a part of permeable channels is irreversibly deteriorated, then the activation of elastic oscillations contributes to postponing the moment of blocking the remaining part and helps to maintain the oil flow through a sample at a constant level. Without
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Numerical investigation on influence of dispersed rock particles on bimslope stability Géotech. Lett. (IF 2.1) Pub Date : 2023-08-17 X. Qin, C. Shao, L. E. Vallejo, D. Yuan, L. Yang
Analysing the stability of bimslopes (i.e. slopes made of bimrock (block-in-matrix rock)) is challenging because bimrock has a complex internal structure. In the study reported here, a stochastic finite-element analysis with the shear-strength-reduction method was conducted to elaborate how dispersed oversized rock particles influence the stability of a vertical bimslope. Numerical models with different
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A theoretical model for the effect of porosity on the relation between uniaxial compressive strength of rocks and point load index Géotech. Lett. (IF 2.1) Pub Date : 2023-06-26 H. Yang, Z. Xu, M. Jiang
Point load test is one of the most adopted indirect ways to estimate uniaxial compressive strength of rocks. Yet, the estimation can be interfered by rock porosity which has rarely been considered in model development. In this study, we proposed a theoretical model for the interpretation of point load test results considering the effect of porosity. The model was developed using the elastic stress
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A bender-element based dynamic penetrometer for the measurement of shear wave velocity and shear strength of in-situ soils Géotech. Lett. (IF 2.1) Pub Date : 2023-06-26 H.-M. Sun, X. Kang
The excavation of underground space during rapid urbanization requires a fully understanding of shear wave velocity (Vs-hh and Vs-hv) and shear strength parameters (cohesive strength (c) and internal friction angle (ϕ)) of soil materials. However, existing laboratory and in-situ testing techniques are usually imprecise, time-consuming and labor-intensive. In this work, a bender-element based dynamic
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Theoretical model for the effect of porosity on correlations of point load tests of rocks Géotech. Lett. (IF 2.1) Pub Date : 2023-06-26 H. Yang, Z. Xu, M. Jiang
Point load test (PLT) is one of the most adopted indirect ways to estimate uniaxial compressive strength of rocks. Yet, the estimation can be interfered by rock porosity that has rarely been considered in model development. In this study, a theoretical model for the interpretation of results of PLTs considering the effect of porosity is proposed. The model was developed using the elastic stress field
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Bender-element-based penetrometers for measuring shear wave velocity and shear strength Géotech. Lett. (IF 2.1) Pub Date : 2023-06-26 H.-M. Sun, X. Kang
A bender-element-based dynamic penetrometer (BE-DP) was developed for the measurement of shear wave velocity (Vs-hh and Vs-hv) and shear strength parameters (cohesive strength (c) and internal friction angle (ϕ)) of soils. Shear wave velocity was measured through two pairs of bender elements installed in the cone shafts. Small-strain stiffness (Ghh and Ghv) and stiffness anisotropic ratio (Ghh/Ghv)
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Modulus weighting method for stiffness estimations of suction caissons in layered soils Géotech. Lett. (IF 2.1) Pub Date : 2023-05-24 S. K. Suryasentana, H. J. Burd, B. W. Byrne, A. Shonberg
This paper presents a new approach, called the modulus weighting method (MWM), for estimating the static stiffness of suction caisson foundations in layered soil conditions. The existing simplified design models for estimating caisson stiffness are limited to non-layered soil conditions, but layered conditions are often found in real-world scenarios. A three-dimensional (3D) finite-element analysis
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A study of the multi-scale compression behaviour of a sand immersed in a viscous liquid Géotech. Lett. (IF 2.1) Pub Date : 2023-05-23 W. Wang, D. Chen, M. R. Coop, B. Yuan
Pore fluids with different viscosities can exist in soils. While the effects of pore fluids have been investigated at the macro-scale, little is known about how they might affect the micromechanics. A novel apparatus allowing a single particle to be crushed while immersed in a liquid was built here. With the help of a high-speed microscope camera, the crushing processes of single silica sand particles
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Rate-dependency of residual shear strength of soils: implications for landslide evolution Géotech. Lett. (IF 2.1) Pub Date : 2023-05-15 J. Duque, M. Loche, G. Scaringi
Shear-rate weakening or strengthening behaviours can effectively control landslide runouts, defining sudden runaway sliding or years-long slow-creep phases. These behaviours are partly controlled by the properties of the basal material. Understanding its stress-strain-time response is crucial in physically-based assessments of landslide dynamics and the associated risk. We investigate the frictional
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Effect of saturation confining pressure on accessible density and shear behaviour of sandy silt tailings Géotech. Lett. (IF 2.1) Pub Date : 2023-05-11 D. Reid, F. Urbina, B. Tiwari, R. Fanni, K. Smith, A. Fourie
Significant reduction in the brittleness of sandy silt/silty sand tailings at high stresses has frequently been observed in laboratory element testing due to curvature of the critical state line and the limiting compression curve. This has led to discussions regarding the range of effective stresses across which such materials can exhibit brittle undrained shearing such that flow liquefaction could
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Laboratory assessment of rubber grid-reinforced ballast under impact testing Géotech. Lett. (IF 2.1) Pub Date : 2023-05-11 A. R. Siddiqui, B. Indraratna, T. Ngo, C. Rujikiatkamjorn
This study presents the use of rubber grids (RGs) fabricated from end-of-life conveyor belts (i.e. discarded from the mining industry) to improve the performance of ballast tracks. The square apertures of these recycled rubber sheets were cast using a waterjet cutting process. A series of large-scale impact tests were performed on ballast specimens stabilised with three different grids of varied effective
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Rate-dependency of residual shear strength of soils: implications for landslide evolution Géotech. Lett. (IF 2.1) Pub Date : 2023-04-25 J. Duque, M. Loche, G. Scaringi
Shear-rate weakening or strengthening behaviours can effectively control landslide runouts, defining sudden runaway sliding or years-long slow-creep phases. These behaviours are partly controlled by the properties of the basal material. Understanding its stress-strain-time response is crucial in physically-based assessments of landslide dynamics and the associated risk. We investigate the frictional
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Rigorous lower and upper bounds for the generalised failure loads of pile groups Géotech. Lett. (IF 2.1) Pub Date : 2023-03-21 F. Potini, D. N. Gorini, R. Conti
A renewed philosophy for the ultimate limit-state design of pile groups is based on the adoption of multiaxial strength envelopes. In this view, this study proposes a limit analysis-based framework providing high-fidelity predictions for the generalised failure loads of piled foundations. This is accomplished through: (a) the development of an upper-bound solution that better approximates the exact
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Cyclically thermally-activated pile under combined axial/horizontal loads in clay Géotech. Lett. (IF 2.1) Pub Date : 2023-02-24 A. Nouri, A. Noorzad, J.-M. Pereira, A. M. Tang
In this study, the influence of cyclic thermal loading on the mechanical response of an energy pile installed in saturated clay subjected to sustained combined axial/horizontal mechanical loading was investigated using physical modelling. After completion of the soil saturation process and prior to starting the thermo-mechanical loading, the pile fixation was released inducing pile head heave. When
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Shear creep behaviour of soil–structure interfaces under thermal cyclic loading Géotech. Lett. (IF 2.1) Pub Date : 2023-02-20 A. Golchin, Y. Guo, P. J. Vardon, S. Liu, G. Zhang, M. A. Hicks
The coupling effect of initial shear stress and thermal cycles on the thermomechanical behaviour of clay concrete and sand–concrete interfaces has been studied. A set of drained monotonic direct shear tests was conducted at the soil–concrete interface level. Samples were initially sheared to half of the material's shear strength and then they were subjected to five heating/cooling cycles before being
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The coupling effect of hydraulic loading and surcharge pressure during suffusion in sandy gravels Géotech. Lett. (IF 2.1) Pub Date : 2023-02-16 Z. Deng, G. Wang, W. Jin
This study focuses on the coupling effect of the imposed hydraulic gradient and surcharge pressure on fine particle loss and skeleton deformation during suffusion. A series of suffusion tests were conducted on an internally unstable sandy gravel under four different hydraulic gradients and three surcharge pressures using a large-scale high-pressure erosion apparatus. The total eroded mass, erosion
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Adaptivity of plate anchors to restrain the impact of seabed trenching Géotech. Lett. (IF 2.1) Pub Date : 2023-02-16 C. Han, J. Liu, P. Yi
The seabed trenching due to chain-soil-water interaction in deepwater moorings is disadvantageous to the holding capacity of the anchor, which threatens the safety of the whole floating system. A measure is proposed in this study to restrain the adverse impact of seabed trenching by utilizing the diving potential of plate anchors. Model tests were conducted to verify the stability and further keying
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A mixed formulation of limit analysis based on the node-based smoothed finite element method for seismic slope stability Géotech. Lett. (IF 2.1) Pub Date : 2023-02-16 H. C. Nguyen
We shortly present a mixed formulation based on the node-based smoothed finite element method for estimating seismic slope stability. The final form of Hellinger-Reissner is cast as the min-max optimization problem with conic constraints. Solving the second-order cone programming directly determines both master fields, stress and displacement. It is shown from the numerical results that the stability
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Development and application of indoor digital drilling test system Géotech. Lett. (IF 2.1) Pub Date : 2023-02-16 Z. Liu, J. Wang, W. Guo, S. Shi, R. Zhao
The digital drilling test provides a new means to realize the real-time acquisition of surrounding rock parameters. In-situ rock drilling can provide more reliable strength quality parameters for rock than indoor experiments. Moreover, it is more capable than existing in-situ rock testing methods, such as the point load and cone penetration tests. This paper introduces the independently developed digital
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Cyclic mobility following plastic strain accumulation in sand Géotech. Lett. (IF 2.1) Pub Date : 2023-02-16 A. Mohammadi, D. Airey
Hybrid failure modes/mechanisms under non-symmetrical cyclic loading (partial stress reversal) have received little attention. This paper presents data from cyclic undrained triaxial tests of sand, with initial static shear stress, to investigate a hybrid failure mechanism that controls the behaviour of dilative sand in a narrow range of non-symmetric stress reversal levels. The results indicate that
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Impacts of reference strain rate and strain level dependency on rate effects in fine-grained soils Géotech. Lett. (IF 2.1) Pub Date : 2023-01-30 S. Robinson, M. J. Brown, J. Knappett, A. Brennan
Viscous rate effects in fine-grained soils may occur in many engineering applications (e.g. dynamically penetrated anchors, sampling, rapid load testing of piles or high-speed soil characterisation), where high strain rates are induced during shear. Often it is difficult to correct for this enhancement of soil strength as fundamental understanding and quantification of rate effects is an area where
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Effects of particle morphology on pore structure and SWRC of granular soils Géotech. Lett. (IF 2.1) Pub Date : 2023-01-10 P. Liu, R.-P. Chen, X. Kang, H. Lei
Given grain-size distribution (GSD) and relative density, the soil–water-retention curve (SWRC) of granular soils can be straightforwardly predicted. However, the evolution of SWRC with different particle morphologies under the same GSD is still unclear. To solve this fundamental problem, herein, four sand analogues with different particle shapes under the same GSD were produced by three-dimensional
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Liquefaction triggering of non-saturated sandy soils Géotech. Lett. (IF 2.1) Pub Date : 2023-01-06 L. Mele, S. Lirer, A. Flora
In saturated sandy soils liquefaction triggering is generally well-identified according to stress or strain criteria. On the contrary, the attainment of liquefaction in non-saturated sandy soils is still a cause of discussion in the scientific community. Even if the liquefaction resistance of non-saturated soils is higher than that of saturated ones, these soils may liquefy, as well. The increasing
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Variation of the mass susceptibility of sandstone after high-temperature heating Géotech. Lett. (IF 2.1) Pub Date : 2023-01-04 Q. Sun, Z. Dong, J. Geng, W. Zhang
Burnt rocks usually exhibit magnetic enhancement, which can be used to detect the spontaneous combustion zone of a coal fire or locate the resources in burnt rocks. To elucidate the mechanisms underlying magnetic enhancement, sandstone is heated to high temperatures between 100 and 1200°C. The mass susceptibility of the sandstone is measured after cooling, and the magnetic characteristics are explained
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Upper bounds for the three-dimensional seismic active earth pressure coefficients Géotech. Lett. (IF 2.1) Pub Date : 2022-12-22 T. Santana, A. Antão, N. Guerra, M. Vicente da Silva
A numerical implementation of the upper-bound theorem of limit analysis is applied to determine two-dimensional (2D) and three-dimensional (3D) active horizontal earth pressure coefficients considering seismic actions through a horizontal seismic coefficient. Results are obtained for vertical wall, horizontal soil, different friction angles of the soil, soil-to-wall friction ratios, horizontal seismic
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Effect of eccentricity on ultimate lateral unit earth pressure of tetrapod piles in clay Géotech. Lett. (IF 2.1) Pub Date : 2022-11-30 Z. Zhao, Y. Wan, D. Dai, L. Ke
This study investigates the ultimate lateral unit earth pressure of rigid tetrapod foundation imposed by eccentric loads, based on a couple of two-dimensional adaptive finite-element limit analyses with lower-bound, upper-bound and 15-node mixed Gauss element formulations. A parameter study is conducted to emphatically explore the influence of eccentricity as well as to assess the role of additional
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Further modification of a generalised 3D Hoek–Brown criterion: the GZZ criterion Géotech. Lett. (IF 2.1) Pub Date : 2022-11-24 H. Chen, H. Zhu, L. Zhang
This paper presents a further modification of the generalised three-dimensional (3D) Hoek–Brown (HB) criterion – the generalised 3D Zhang-Zhu (GZZ) criterion. Specifically, a modification was made by introducing a 3D version of effective mean stress to replace the original two-dimensional (2D) version of effective mean stress in the GZZ criterion. The modification overcomes the non-smoothness and non-convexity
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Critical state shear strength at concrete-sand-bentonite slurry interfaces: mix proportions and rate effects Géotech. Lett. (IF 2.1) Pub Date : 2022-11-09 K. G. O'Dwyer, B. A. McCabe, B. B. Sheil
This paper describes direct shear testing of a range of sand-bentonite slurry mixes, identified as a gap in the literature. In the absence of a concrete interface, there was an apparent transition zone from sand-governed strength (bentonite content ≤30%) to clay-governed strength (bentonite content ≥80%), which was linked to the sample void ratio. When a concrete interface was introduced, the critical
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Comparing laboratory and field samples of lime–cement-improved Norwegian clay Géotech. Lett. (IF 2.1) Pub Date : 2022-11-03 P. Paniagua, F. Å. Falle, S. Hov, K. R. Tekseth, F. Mirzaei, D. W. Breiby
Improvement of the structural integrity of clay-rich soil is crucial to mitigate risks related to ground movements, and representative procedures are needed to quantitatively describe the reproducibility and authenticity of laboratory-mixed (LM) clay model specimens. Here, two standardised industry protocols for preparation of laboratory lime–cement (LC) improved clay samples are compared with field
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Effect of base roughness on flow behaviour and size segregation in dry granular flows Géotech. Lett. (IF 2.1) Pub Date : 2022-10-21 Y. Zhao, Y. Luo, W. Wang, S. Liu, Z. Zhan
Three bases with increasing roughness were designed by adjusting the geometric relationships of particles bonded to the base, to study the roughness effect on flow behaviour and size segregation in bidisperse granular chute flows. In light of limited research on accurate tracking of different particles in bidisperse granular flows, particle tracking velocimetry, which allows tracking of large and small
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Application of the unified CPT method for driven piles to layered deposits Géotech. Lett. (IF 2.1) Pub Date : 2022-10-20 E. M. Bittar, B. M. Lehane, Z. Liu, F. Nadim, S. Lacasse
The ongoing and increasing demand for offshore piles has motivated the development of more reliable design methods and led to the recent development of ‘unified’ cone penetration test design methods to predict the axial capacity of driven piles installed in sand deposits and in clay deposits. However, many sites encountered in practice contain both sand and clay layers as well as silt layers and it
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Undrained trapdoor and tunnel face stability revisited Géotech. Lett. (IF 2.1) Pub Date : 2022-09-29 T. Pferdekämper, G. Anagnostou
In this study, closed-form solutions are presented for two classical problems: the load exerted on strip or circular trapdoors and the stability of tunnel headings in purely cohesive soils, considering both the case of a constant undrained shear strength and of a linear vertical strength profile. The solutions are based on a minor modification of Gunn's lower-bound plasticity solution. According to
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Intrinsic permeabilities of transparent soil under various aqueous environmental conditions Géotech. Lett. (IF 2.1) Pub Date : 2022-09-16 G. Yan, H. Shi, Y. Ma, A. Scheuermann, L. Li
This study investigates the intrinsic permeability of two water-based transparent soil surrogates (Aquabeads and hydrogel beads) in various aqueous environments. To maximise the efficiency of seepage tests for different solutes (salt and a surfactant) at different concentrations, a rapid approach was established to estimate the intrinsic permeabilities of these water-based granular polymers. Due to
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Influence of mineral mesoscopic structure on rock dynamic fragmentation under compression Géotech. Lett. (IF 2.1) Pub Date : 2022-08-30 M. Ju, Y. Hao, Z. Guo, H. Xing
Three types of rock were chosen to investigate the effect of mineral mesoscopic structure on rock fragmentation under dynamic compression. The fragments collected from the tested sandstones and granites were studied using an image-processing method, and the relationship between the fractal dimension of rock fragments and the mechanical properties in dynamic compression was established. Four failure
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Distributed Acoustic Sensing in Soil for Infrastructure Monitoring SNR Evaluation Géotech. Lett. (IF 2.1) Pub Date : 2022-08-30 M. C. L. Quinn, C. D. P. Baxter, G. R. Potty
Fibre optic Distributed Acoustic Sensing (DAS) systems provide vibration response information comparable to accelerometers, geophones, and seismometers and may become widely used for infrastructure monitoring. DAS can be used to monitor earthquake activity, carbon sequestration, pipelines, and roadway/railway subgrade integrity, however little is known about the effect of soil type and burial method
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Colloidal-induced permeability degradation assessment of porous media Géotech. Lett. (IF 2.1) Pub Date : 2022-08-23 E. V. Kozhevnikov, M. S. Turbakov, E. A. Gladkikh, E. P. Riabokon, V. V. Poplygin, M. A. Guzev, C. Qi, H. Jing
The paper presents the methodology and results of coreflooding, taking into account the decrease in the permeability caused by the migration of natural colloids during fluid injection. As a porous medium, core samples of consolidated slightly clayey sandstone from one of the oil fields of the Komi Republic (Russia) were used. The coreflooding methodology implied a cyclic change in the injection rate
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Effect of initial normal stress on shear-induced non-linear fluid flow through fractures Géotech. Lett. (IF 2.1) Pub Date : 2022-08-18 Z. Liu, S. Li, X. Feng, R. Liu
This study investigated the effect of initial normal stress on the non-linear hydraulic properties of fractures during shearing. A natural rough fracture is utilised to generate the rough fracture model and a mathematical expression for predicting the normal displacement during shearing is used, after which the validity is verified. Finally, the non-linear flow rate – hydraulic gradient relationships
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Colloidal-induced permeability degradation assessment of porous media Géotech. Lett. (IF 2.1) Pub Date : 2022-08-03 E. V. Kozhevnikov, M. S. Turbakov, E. A. Gladkikh, E. P. Riabokon, V. V. Poplygin, M. A. Guzev, C. Qi, H. Jing
The paper presents the methodology and results of coreflooding, taking into account the decrease in the permeability caused by the migration of natural colloids during fluid injection. As a porous medium, core samples of consolidated slightly clayey sandstone from one of the oil fields of the Komi Republic (Russia) were used. The coreflooding methodology implied a cyclic change in the injection rate
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Energy pile skin friction at interface in clays under temperature cycles Géotech. Lett. (IF 2.1) Pub Date : 2022-08-01 S. Maghsoodi, O. Cuisinier
In energy geostructures, the long-term shaft resistance is affected by cyclic thermo-mechanical loads associated with structural loads and cyclic thermal solicitations. This study aims to investigate the effect of monotonic and cyclic thermal loads on normally consolidated (NC) and overconsolidated (OC) kaolin clay–rough steel interface. The peak shear stress of interface increased with temperature
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Visualization of pile penetration using mechanoluminescent-coated particles Géotech. Lett. (IF 2.1) Pub Date : 2022-07-27 A. Kondo, D. Takano, E. Kohama, R. J. Bathurst
Pile model penetration tests were conducted in a transparent plane strain container filled with granular mechanoluminescent-coated particles. The pile models were constructed with flat- and cone-shaped tips. Load transmission through the analogue granular soil was captured by taking images of the light emissions from one side of the container that were triggered by inter-particle force-induced mechanoluminescence
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Influence of fines content on the undrained flow instability of loess Géotech. Lett. (IF 2.1) Pub Date : 2022-07-26 F. Liu, Q. Xu, Y. Zhang, J. E. Macedo
The influence of fines content (FC) on flow instability of intact and reconstituted Chinese loess is studied under undrained monotonic loading using conventional triaxial tests. The undrained behaviour of a mixed loess system indicates that the increasing plastic fines reduce the peak strength with little effect on the critical state friction angle. The changing FC can result in parallel translation
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Introducing plastic zone and tangential stress into tunnelling strain rockburst prediction Géotech. Lett. (IF 2.1) Pub Date : 2022-07-26 M. M. He, K. Q. Wu, Z. Q. Zhang
This paper on a criterion for rockbursts is focused mainly on the stress concentration and gradient change of the tangential stress of the surrounding rock. Two parameters are introduced into tunnelling strain rockburst prediction: the radius of the plastic zone and the radial stress at the elastoplastic junction after excavating the surrounding rock. A new rockburst criterion is proposed based on
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Novel evaluation of mass polar moment of inertia of the drive plate in resonant column Géotech. Lett. (IF 2.1) Pub Date : 2022-07-12 Z. H. Khan, G. Cascante, R. E. Ahmed
Resonant column (RC) is a standard laboratory test for the dynamic characterization of soils. Mass polar moment of inertia (MPMI) of the drive plate of RC is required for the solution of equation of motion for a specimen-mass system in RC. In standard procedure, the MPMI is evaluated by testing of calibration probes. Studies have shown that torsional stiffness of the probes have significant effect
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A simple method to reduce mesh dependency in modelling landslides involving brittle soils Géotech. Lett. (IF 2.1) Pub Date : 2022-07-11 A. Troncone, L. Pugliese, A. Parise, E. Conte
This paper focuses on the numerical simulation of the deformation processes occurring in the slopes when soils with strain-softening behaviour are involved. In these circumstances, a progressive failure may occur with the consequent motion of the unstable soil mass in the post-failure stage. This problem can be only solved using advanced numerical techniques capable also of accounting for the occurrence
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Infiltration behaviour into sand of bentonite slurry with guar gum Géotech. Lett. (IF 2.1) Pub Date : 2022-06-20 H. Lei, X. Liu, F. Shi, C. Ma
Bentonite slurry is widely used in various projects due to its excellent engineering properties. The behaviour of slurry infiltration, especially filter cake formation, is directly related to the effect of slurry. This paper proposes an improved apparatus to investigate the infiltration of a novel bentonite slurry, especially in the dynamic infiltration process of the slurry-driven shield, which provides
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Assessing temperature dependence of soil water adsorption strength by molecular simulation Géotech. Lett. (IF 2.1) Pub Date : 2022-05-18 Jianbo Wang, Zemin Qiu, Chao Zhang, Renpeng Chen
Soil water adsorption strength represents the changing rate of adsorptive water content with regard to soil suction or water potential changes, dictating the magnitude of the soil water-retention curve at the dry end. Non-isothermal conditions are frequently encountered in energy and environmental geotechnics, posing the requirement to assess temperature effects on soil water adsorption strength. Yet
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Effects of initial water content on compression behaviour of municipal sewage sludge Géotech. Lett. (IF 2.1) Pub Date : 2022-05-11 R.-M. Yang, R.-W. Wei, Z.-N. Zhang, T.-L. Zheng, L. Ma
To investigate effects of initial water content on compression behaviour of municipal sewage sludge and clarify its intrinsic compression characteristics. Oedometer tests were conducted on sludge with various initial water content of 0·13–1·48 times the liquid limit. It is observed that the sludge is organic high liquid limit silt, whose e–log σ′v compression curves are inverse ‘S’ shape due to organic
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Three-dimensional limit analysis with Lade–Duncan criterion Géotech. Lett. (IF 2.1) Pub Date : 2022-05-04 A. N. Antão, M. Vicente da Silva
The paper describes the three-dimensional numerical implementation of the Lade–Duncan criterion in a finite-element limit analysis code. Validation is done using examples with a known solution. To conclude the proposed numerical tool is applied to the calculation of the ultimate bearing capacity of square footing.
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Optimising an output of a slip line field using a chaotic swamp optimisation algorithm Géotech. Lett. (IF 2.1) Pub Date : 2022-04-27 Thanh Liem Vo, Thi Ngoc Mac, Duy Minh Do
In solving earth pressure problems, many input parameters are needed to account for more realistic soil properties and complex boundary conditions. Finding an optimal output while considering many inputs can be costly and time consuming. The input parameters themselves may be significantly uncertain due to lack of laboratory test data and variations in design and construction stages. Adopting an optimisation
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Strength characteristics of brittle rocks under multi-stage intermediate principal stress loading Géotech. Lett. (IF 2.1) Pub Date : 2022-04-24 L. Shi, C. C. Li, X. Zhang, X.-T. Feng, G. Wang
A series of single-stage true triaxial compression (TTC) tests and multi-stage intermediate principal stress (σ2) loading tests were carried out on three types of brittle rock specimens in this study to examine the influence of σ2 and the validity of obtaining strength parameters by using a multi-stage loading method under true triaxial stress conditions. There exists a critical σ2 at which the rock
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Compressibility and shear strength of a tropical fibrous peat Géotech. Lett. (IF 2.1) Pub Date : 2022-04-07 Z.-S. Li, W. Rahayu, H. Souli, B. S. Soepandji, J.-M. Fleureau
This study examines the compressibility and shear strength of an Indonesian fibrous peat through oedometric and consolidated undrained (CU) triaxial tests. The influence of fibres is considered by preparing two series of specimens – undisturbed and reconstituted. For the latter, the coarse fibres larger than 80 μm were removed by wet sieving. Oedometric test results show that, as the coarse fibres
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Coupled effects of stress state and void ratio on thermal conductivity of saturated soils Géotech. Lett. (IF 2.1) Pub Date : 2022-04-07 S. Q. Cui, C. Zhou
Soils surrounding energy geostructures (e.g. energy piles and borehole heat exchangers) always have different overburden pressures and void ratios. Their thermal conductivities are important for analysing the performance of energy geostructures such as the heat exchange rate between soils and geostructures. So far, however, the coupled effects of stress state and void ratio on thermal conductivity
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Relating cone penetration resistance to sand state using the material point method Géotech. Lett. (IF 2.1) Pub Date : 2022-04-04 M. Martinelli, F. Pisanò
Cone penetration tests (CPTs) can quantitatively inform about the mechanical state of a sand. However, relating measured cone resistance values to sand state requires complex back-analysis of the processes occurring in the soil during the test. This paper provides new evidence of the value added in this area by modern large-deformation modelling based on the material point method (MPM). It is shown
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Optimised screw pile design for offshore jacket foundations in medium–dense sand Géotech. Lett. (IF 2.1) Pub Date : 2022-04-04 B. Cerfontaine, M. J. Brown, C. Davidson, Y. U. Sharif, M. Huisman, M. Ottolini
Screw piles are well-suited foundations for offshore jacket structures, as they can be installed without significant underwater noise and have a large axial capacity. However, installation requirements for such large piles must be reduced to enable their installation in the field. This study combines geometry and installation optimisation to lower force and torque installation requirements. An original