Hydraulic path dependence of shear strength for compacted loess  

作　　者：Pan Chen Shengao Jia Xiaoqi Wei Pingping Sun Panpan Yi Changfu Wei 

机构地区：[1]State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China [2]University of Chinese Academy of Sciences,Beijing,100049,China [3]Xuzhou Highway Engineering Corporation,Xuzhou,221000,China [4]School of Human Settlements and Civil Engineering,Xi’an Jiaotong University,Xi’an,710061,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第7期1872-1882,共11页岩石力学与岩土工程学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41877269,12002243,41907046).

摘　　要：Shear strength is an essential geotechnical parameter for assessing the landslide potential of loess slopes under rainfall infiltration and farm irrigation conditions on the loess plateau.However,the hydraulic path dependence of shear strength for compacted loess under varying rainfall infiltration conditions has not been thoroughly investigated yet.To this end,a series of direct shear tests and nuclear magnetic resonance(NMR)measurements are carried out on compacted loess.The shear strength tests were continuously implemented on loess specimens under scanning wetting paths besides initial drying paths.The experimental data quantitatively verify the significant effect of hydraulic paths applied to specimens on shear strength of compacted loess.The unique failure envelope of shear strength of loess is identified under the effective stress framework based on intergranular stress,which verifies that the effective stress framework can consider the effect of hydraulic paths on shear strength.Based on the effective stress,a shear strength formula is proposed to characterize shear strengths under varying hydraulic paths,in which the parameters from the soil-water retention curve and shear strength at saturated state are simply required.The proposed shear strength formula can properly predict the measured shear strength data of compacted loess experiencing three hydraulic paths.Furthermore,the distribution curves of transverse relaxation time for pore water in soil under varying hydraulic paths are simultaneously measured using the NMR method.The physical mechanism for the difference in shear strength of loess subjected to different hydraulic paths can be uncovered based on soil-water evolutions in pores in microscale.

关 键 词：Shear strength LOESS Hydraulic hysteresis Effective stress Nuclear magnetic resonance(NMR) 

分 类 号：TU41[建筑科学—岩土工程]