Determination of the shear strength of unsaturated soils using the multistage direct shear test

Nam, Soonkie; Gutierrez, Marte; Diplas, Panayiotis; Petrie, John

doi:10.1016/j.enggeo.2011.06.003

Cited by 80 publications

(37 citation statements)

References 30 publications

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“…On the other hand, determining the SSS-related parameters by laboratory tests is a complicated task and mainly requires performing destructive tests. Moreover, high spending costs [8], as well as learning special skills for working with complex apparatus [9][10][11][12] are other disadvantages of direct approaches for SSS measurement.…”

Section: Introductionmentioning

confidence: 99%

Spotted Hyena Optimizer and Ant Lion Optimization in Predicting the Shear Strength of Soil

et al. 2019

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Two novel hybrid predictors are suggested as the combination of artificial neural network (ANN), coupled with spotted hyena optimizer (SHO) and ant lion optimization (ALO) metaheuristic techniques, to simulate soil shear strength (SSS). These algorithms were applied to the ANN for counteracting the computational drawbacks of this model. As a function of ten key factors of the soil (including depth of the sample, percentage of sand, percentage of loam, percentage of clay, percentage of moisture content, wet density, liquid limit, plastic limit, plastic Index, and liquidity index), the SSS was considered as the response variable. Followed by development of the ALO–ANN and SHO–ANN ensembles, the best-fitted structures were determined by a trial and error process. The results demonstrated the efficiency of both applied algorithms, as the prediction error of the ANN was reduced by around 35% and 18% by the ALO and SHO, respectively. A comparison between the results revealed that the ALO–ANN (Error = 0.0619 and Correlation = 0.9348) performs more efficiently than the SHO–ANN (Error = 0.0874 and Correlation = 0.8866). Finally, an SSS predictive formula is presented for use as an alternative to the difficult traditional methods.

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Section: Introductionmentioning

confidence: 99%

Spotted Hyena Optimizer and Ant Lion Optimization in Predicting the Shear Strength of Soil

et al. 2019

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“…Flow to the lower reach is primarily controlled by releases from the Roanoke Rapids Dam. The effect of this flow regulation on bank retreat has been the subject of recent investigations [ Hupp et al ., ; Nam et al ., ]. Reservoir releases were relatively steady for both survey periods, with the discharge Q in May close to the mean annual flow ( Q = 228 m 3 s −1 ) and at bankfull in June ( Q = 565 m 3 s −1 ).…”

Section: Field Measurementsmentioning

confidence: 86%

Combining fixed- and moving-vessel acoustic Doppler current profiler measurements for improved characterization of the mean flow in a natural river

et al. 2013

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[1] A methodology is presented to quantify the mean flow field in a natural river with a boat-mounted acoustic Doppler current profiler (ADCP). Moving-vessel (MV) and fixedvessel (FV) survey procedures are used in a complementary fashion to provide an improved representation of mean three-dimensional velocity profiles along a cross section. Mean velocity profiles determined with FV measurements are rotated to a stream-fitted orthogonal coordinate system. The orientation of the coordinate system is established using MV measurements. The methodology is demonstrated using measurements obtained at two study sites on the lower Roanoke River for the mean annual flow (228 m 3 s À1 ) and a flow that produces bankfull conditions at the sites (565 m 3 s À1 ). Results at a meander bend identify well-known flow features, including a main circulation cell, outer-bank circulation, and separation at the inner bank. This methodology also provides a framework for comparing time-averaged velocity profiles from FV measurements with spatially averaged profiles from MV measurements. Results indicate that MV measurements can provide a reasonable estimate of the streamwise velocity at many locations. The MV measurements obtained here, however, were not sufficient to resolve the spanwise velocity component.Citation: Petrie, J., P. Diplas, M. Gutierrez, and S. Nam (2013), Combining fixed-and moving-vessel acoustic Doppler current profiler measurements for improved characterization of the mean flow in a natural river, Water Resour. Res., 49, 5600-5614,

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“…To eliminate the effect of soil variability on the results, multi-stage testing was used to maximise the amount of shear strength information that could be obtained from only one specimen. This technique has been used successfully in the past to determine shear strength parameters for both saturated and unsaturated soils in triaxial apparatus and in direct shear apparatus (Sridharan & Rao, 1972;Ho & Fredlund, 1982;Gan & Fredlund, 1988;Soranzo, 1988;Nam et al, 2011;Sharma et al, 2011;Hormdee et al, 2012).…”

Section: Chemical Impact On Shear Strength Combined Effect Of Osmoticmentioning

confidence: 96%

Chemo-hydro-mechanical behaviour of compacted Boom Clay: joint effects of osmotic and matric suctions

Mokni¹,

Romero²,

Olivella³

2014

Géotechnique

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An experimental programme involving osmotic and matric suction controlled tests is carried out to investigate the effects of increasing pore fluid concentration, chemical cycling (salinisation/dilution) and matric suction on the liquid retention properties, shear strength and volume change behaviour of Boom Clay. This Tertiary Clay formation has been thoroughly investigated as a possible host material for the disposal of Eurobitum bituminised radioactive waste (BW) in Belgium. Within this context chemical impact and partially saturated conditions are studied in a combined way to cover a wide range of in-situ states induced by underground construction, ventilation and diffusion of a large amount of sodium nitrate (NaNO3) (contained in the bituminised waste). Statically compacted specimens are prepared at different sodium nitrate concentrations or are exposed, at constant vertical stress, to sodium nitrate salinisation or pore water dilution. An aggregated structure with a double porosity network is induced on salinisation and subsequent compaction even at high water contents. An increase in pore fluid concentration enhances the aggregation of the microstructure and reduces the liquid retention properties of the material. Results of oedometer tests performed under constant matric suction and increasing osmotic suction show shrinkage of the sample, a decrease of the compressibility and an increase in the preconsolidation stress. Shear strength results have been interpreted using a single constitutive stress (average skeleton stress) to take into account matric suction and chemical effects on degree of saturation and on microstructural changes. A unique linear shear strength failure envelope has been obtained for the tests performed at different osmotic and matric suctions. The modification of the liquid retention behaviour of the material induced by salinisation has proven to be a crucial aspect for the interpretation of the obtained results.Peer ReviewedPostprint (published version

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Determination of the shear strength of unsaturated soils using the multistage direct shear test

Cited by 80 publications

References 30 publications

Spotted Hyena Optimizer and Ant Lion Optimization in Predicting the Shear Strength of Soil

Spotted Hyena Optimizer and Ant Lion Optimization in Predicting the Shear Strength of Soil

Combining fixed- and moving-vessel acoustic Doppler current profiler measurements for improved characterization of the mean flow in a natural river

Chemo-hydro-mechanical behaviour of compacted Boom Clay: joint effects of osmotic and matric suctions

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