Experimental study on seepage characteristics of dry and wet sandy loess under hydro-mechanical coupling
Cai Guoqing1,2 Liu Qianqian2 Yang Yu3 Li Jian2 Zhao Chenggang2
1. Key Laboratory of Urban Underground Engineering of the Ministry of Education, Beijing Jiaotong University, Beijing 100044, China;
2. School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China;
3. China Construction Fifth Engineering Division Co., Ltd., Changsha 410000, China
Abstract：A hydro-mechanical coupling apparatus is developed to explore the unsaturated hydraulic conductivity characteristics of dry and wet sandy loess under hydro-mechanical coupling action. Based on the test apparatus, a series of seepage tests on one-dimensional columns of sandy loess are carried out using the “the wetting front advancing method” for completely dry soil columns and wet soil columns. The variation laws of the wetting front, hydraulic conductivity, and axial deformation under the hydro-mechanical coupling are obtained, and the corresponding microscopic mechanism of sandy loess is studied with scanning electron microscope experiment. It is found that: (1) At the early stage of infiltration, the wetting front advancing velocity of the dry soil column and the wet soil column are approximately the same, while in the late period of infiltration, the wetting front advancing velocity of the dry soil column is significantly less than that of the wet soil column. (2) Given the same axial load, the slope of the linear segment of the hydraulic conductivity function curve of the wet soil column is greater than that of the dry soil column. With the axial load increases, the slopes of the linear segment of the hydraulic conductivity functions of the two types of soil columns decrease slightly. When the seepage flow is stable, the stable hydraulic conductivity of the wet soil column is greater than that of the dry soil column. (3) Compared with the wet soil column, the dry soil column has obvious water sensitivity, and after wetting its deformation increases significantly. The research results have important theoretical and practical significance for revealing the seepage and deformation mechanism of surrounding rock of the sandy loess of Yangcheng Tunnel and guiding the construction safety of the tunnel.
蔡国庆 刘倩倩 杨雨 李舰 赵成刚. 水-力耦合作用下干燥和湿润砂质黄土渗透特性试验研究[J]. 土木工程学报, 2022, 55(3): 74-82.
Cai Guoqing Liu Qianqian Yang Yu Li Jian Zhao Chenggang . Experimental study on seepage characteristics of dry and wet sandy loess under hydro-mechanical coupling. 土木工程学报, 2022, 55(3): 74-82.
