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Analysis of the Plastic Zone of Surrounding Rock Under Seepage and a Non-Axisymmetric Load
(1 The MOE Key Laboratory of Coalmine Safety and High Efficiency Mining, Anhui University of Science and Technology, Huainan 232001; 2.School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031)
Abstract Taking the seepage body force into consideration, this paper derives the rock stress distribution and plastic zone expressions under the seepage field and analyzes the relationships of the plastic zone range to the porewater pressure, lateral pressure coefficient and the ratio K between the rock mass strength and initial geostress. The results show that the seepage field has an effect on the plastic zone range, but not on its shape. With variation of lateral pressure coefficients and K values, the effect of seepage on the plastic zone range presents anisotropy along different directions. Furthermore, the anisotropic degree decreases gradually with the increase of the lateral pressure coefficient and K value. The lateral pressure coefficient and the K value not only affect the plastic zone range, but also its shape. When K＜1, the effect from the lateral pressure coefficient plays an important role. Whereas, rock mass strength plays the leading role when K＞1, namely, the plastic zone range decreases gradually with the increase of the rock's compressive strength. Additionally, the plastic zone is more likely to appear at the two sides of the tunnel with a decrease of the lateral pressure coefficient.
Abstract：
Taking the seepage body force into consideration, this paper derives the rock stress distribution and plastic zone expressions under the seepage field and analyzes the relationships of the plastic zone range to the porewater pressure, lateral pressure coefficient and the ratio K between the rock mass strength and initial geostress. The results show that the seepage field has an effect on the plastic zone range, but not on its shape. With variation of lateral pressure coefficients and K values, the effect of seepage on the plastic zone range presents anisotropy along different directions. Furthermore, the anisotropic degree decreases gradually with the increase of the lateral pressure coefficient and K value. The lateral pressure coefficient and the K value not only affect the plastic zone range, but also its shape. When K＜1, the effect from the lateral pressure coefficient plays an important role. Whereas, rock mass strength plays the leading role when K＞1, namely, the plastic zone range decreases gradually with the increase of the rock's compressive strength. Additionally, the plastic zone is more likely to appear at the two sides of the tunnel with a decrease of the lateral pressure coefficient.
GAO Zhao-Ning-1,
MENG Xiang-Rui-1,
Wang-Guang-Di-2
.Analysis of the Plastic Zone of Surrounding Rock Under Seepage and a Non-Axisymmetric Load[J] MODERN TUNNELLING TECHNOLOGY, 2014,V51(2): 70-75
2014, Vol. 51 