Development and application of an instrument for simulating wetting-drying cycles of expansive soils under loads  

作　　者：DONG Jun-gui LV Hai-bo WU Wei 

机构地区：[1]School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510641, China [2]College of Civil Engineering and Architecture, Guilin University of Technology, Guilin 541004, China

出　　处：《Journal of Mountain Science》2018年第11期2552-2560,共9页山地科学学报（英文）

基　　金：provided by the National Natural Science Foundation of China (Grant No. 51169005)

摘　　要：Alternating rainfall and evaporation in nature severely impact the shear strength of expansive soils. This study presents an instrument for simulating the effect of wetting–drying cycles on the strength of expansive soils under different loads, and its testing error is verified. With this instrument,direct shear tests were performed on samples experiencing 0-6 cycles under vertical loads of 0 kPa,5 kPa, 15 kPa, and 30 k Pa. The results found that this instrument provides a new method for evaluating the effects of wetting–drying cycles on soils, and this method represents actual engineering conditions more accurately than do preexisting methods. It accurately controls the water content within 1% while simulating the specified loads at different soil depths.Cohesion is significantly affected by wetting–drying cycles, while the friction angle is not as sensitive to these cycles. Decrease in shear strength can be attributed to the fissures in soils caused by wetting–drying cycles. The existence of vertical loads effectively restricts shrinkage fissuring and cohesion attenuation, consequently inhibiting the attenuation of shear strength.

关 键 词：Expansive soils Wetting-drying cycle Instrument Load Shear strength 

分 类 号：TU443[建筑科学—岩土工程]