Numerical analysis of cylindrical cavity expansion underpartially drained condition(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2021年1期
- Page:
- 11-20
- Research Field:
- 道路工程
- Publishing date:
Info
- Title:
- Numerical analysis of cylindrical cavity expansion underpartially drained condition
- Author(s):
- ZHOU Hang; YU Hao; WANG Zeng-liang; LI Xian-cheng; CHEN Zhi-xiong
- (1. Key Laboratory of New Technology for Construction of Cities in Mountain Area of Ministry of Education,Chongqing University, Chongqing 400045, China; 2. School of Civil Engineering,Chongqing University, Chongqing 400045, China)
- Keywords:
- road engineering; numerical analysis; partially drained; cylindrical cavity expansion; MCC model; effective stress; excess pore pressure
- PACS:
- -
- DOI:
- -
- Abstract:
- Aimed at the problem that existing cavity expansion theory cannot consider the partially drained condition of the soil, a numerical model of cylindrical cavity expansion under partially drained condition was established through ABAQUS software, combined with the modified Cam clay model (MCC), which was used to describe the stressstrain relationship of the soil. And the numerical analysis of cylindrical cavity expansion under different expansion rates was conducted. The calculation process of the numerical model was divided into three steps: initial, geostress balance, and loading. In the loading step, the pore pressure, which equals to the initial pore pressure, was applied to the right boundary of the model to simulate the drained condition, the displacement of the models left boundary was changed to realize the expansion process, and expansion rates were controlled by modifying the calculation time of the loading step. The reliability of the numerical model was verified by comparing the numerical solutions with the theoretical solutions under two extremely drained conditions of completely drained and completely undrained. Parameter analysis was carried out for the five constitutive parameters (λ，κ,ν′,M,R) of the MCC model, and changes of effective stress and excess pore pressure of the soil at the cavity wall after cavity expansion under partially drained condition were obtained. The results show that λ only affects the soil stress, which closes to the completely drained section, and basically has no effect on the excess pore pressure. The parameter κ has a slight influence on the soil stress and excess pore pressure in the partially drained section. When ν′>0.3, it can be clearly found that the influence on effective stress and excess pore pressure increases. The increase of M makes the effective stress of the completely drained section and the partially drained section show an increasing trend. Considering the soil stress history R, in the case of high over consolidation ratio, the range, which gradient equals as zero, increases with the R increasing, when the effective stress curve is near completely drained section, and changing drained conditions has little effect on the soil stress. The higher over consolidation ratio makes the dissipation rate of excess pore pressure faster. The five independent variables are compared and analyzed, and it is found that the influence of R on the excess pore pressure is significantly greater than the other four parameters. 2 tabs, 13 figs, 29 refs.
Last Update: 2021-01-25