doi:10.16186/j.cnki.1673-9787.2020060023

Received:2020/06/09

Revised:2020/09/24

Published:2022/03/15

Effect of salt solution concentrations on shear strength of unsaturated expansive soil

LEI Shengyou, YUAN Wenzhi, ZHAI Zhigang, TIAN Gang, CHEN Yufei, LI Siyu, LU Di, LIU Mingyu

School of Highway, Chandan University,Xi'an 710064 , Shaanxi, China

Abstract: In order to explore the effect of salt solution concentration on the shear strength of unsaturated expansive soil,based on the traditional Fredlund's unsaturated soil shear strength formula,the matrix suction was simplified to a constant,the osmotic pressure was introduced,and then the shear strength formula of unsaturated expansive soil under the intervention of salt solution was proposed.Furthermore,indoor direct shear tests were performed on the modified expansive soils with 4 concentrations of NaCl solution and KCl solution.The stressdeformation curve,shear strength line and shear strength index change curve were obtained.The test results showed that the shear strength of modified soil was generally lower than that of plain expansive soil.The proposed shear strength formula fitsted well with the test data,which also reflected the shear strength changes accurately.The influence of salt solution on the shear strength and cohesion of unsaturated expansive soil was achieved by changing the thickness of the electric double layer,the contact between soil particles and the structural characteristics.Finally,the micro mechanism of the shearing of expansive soils under condition of salt solution was further discussed.

Key words:unsaturated expansive soil;salt solution;direct shear test;shear strength

 盐溶液质量分数对非饱和膨胀土抗剪强度的影响_雷胜友.pdf