Experimental study on deformation properties of unsaturated compacted soil based on digital image measurement

Due to the end restraint or the restraint of contact transducers to sample deformation, the results of conventional strain measurement method can not reflect the properties of sample deformation comprehensively. The digital image measurement method can measure the deformation of overall and local sample non-intrusively and selectively and can overcome some shortcomings of using conventional strain measurement method for unsaturated soil sample in suction-controlled triaxial tests. The deformation measurement results of unsaturated compacted soil samples show that the end restraint has significant effect on the deformation of the sample. The deformation properties of middle 1/3 sample are evidently different from those of the overall sample that is affected by the end restraint in suction-controlled isotropic loading and triaxial compression tests. The deformation measurement results of middle 1/3 sample can really correspondingly reflect basic deformation properties of unsaturated soil and study a constitutive model preferably

Evolution Prediction of Hysteresis Behavior of Sand under Cyclic Loading

Soil cyclic degradation is a serious issue that should be considered in engineering design and maintenance. The hysteretic response causes strength degradation and excessive settlement of soil structure in engineered and natural geosystems. Hysteresis is essentially the coupling deformation of elastic and plastic components during reloading and unloading processes. Conventional hysteretic models for sand in the elastoplastic framework rely highly on yield surface or potential surface evolution and fall short on complexity and inaccuracy. This study proposes a decoupling method to describe the hysteretic response of sand. In contrast to the conventional elastoplastic approach, this decoupling method can directly decouple the elastic and plastic components by determining the boundary between the elastic strain extension domain and the plastic strain extension domain for each stress cycle. In this way, the elastic and plastic stress–strain branches during cyclic loading can be separately obtained, and the corresponding elastic and plastic parameters are employed to characterize mechanical behavior. With the respective evolution of elastic and plastic strains, the hysteretic behavior of sand is reproduced by combining all the branches. Finally, this decoupling method is validated by three conventional cyclic loading tests. The predictions are consistent with the experiments, indicating that the decoupling method is generally effective in describing the hysteretic behavior under cyclic loading. This decoupling method provides new insight to obtain elastic and plastic deformation behaviors separately, without recourse to complicated plastic surface and hardening law

T144

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information). Supporting informatio

DEM

‘DEM’ spreadsheet is the simulation results. The test information of the numerical samples is included in it. Supporting informatio

T514

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information). Supporting informatio

T134

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information). Supporting informatio

T114

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information). Supporting informatio

T111

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information). Supporting informatio

PF6

‘PS’ and ‘PF’ spreadsheets are the data of the prediction and calibration tests. (The data in this series are overall stress and strain information). Supporting informatio

T112

‘T’ series spreadsheets are the raw data of all tests. (The data in this series are overall stress and strain information). Supporting informatio