巷道布置对围岩稳定性影响的数值模拟

采用理论分析不同应力场下巷道轴线与最大水平主应力方向夹角的最佳角度，利用数值模拟不同夹角情况下，巷道围岩应力分布、正前方应力分布及变形特征。得出：1）最大水平主应力σH〉最小水平主应力σh〉垂直主应力σr时，最佳角度为0°；σt〉σH〉σh时，最佳角度为90°；σH〉σa〉σA时，最佳夹角为α0.2）巷道开挖后，水平应力在两帮出现应力降低区，在顸、底板出现应力集中区；垂直应力在两帮出现应力集中区，在顶、底板出现应力降低区；随角度变化，应力变化区均有明显变化，正前方断面的最大主应力变化明显。3）巷道达到最佳角度时，围岩变形相对较小，最大主应力围绕在巷道周边，呈环状或类环状分布；其它角度时，围岩变形相对较大，最大主应力逐渐向顶、底板的四角或两帮发展。

Numerical Simulation of Effect of Roadway Layout on Stability of Surrounding Rock

Theoretical analysis on the best angle between field tunnel axis and the direction of maximum horizontal principal stress, and the stress distribution in surrounding rock, in front of the stress distribution and deformation based on numerical simulation from different angle are given. It is obtained that ： 1 ） When Maximum horizontal principal stress σH 〉 Minimum horizontal principal stress σh 〉 Vertical principal stress σt ,the best angle is 0 degrees;when σH 〉 σt 〉 σh ,the best angle α0 ;when σt 〉 σH 〉 σh ,the best angle is 90 degrees. 2） After the laneway have been dug,the horizontal stress will decrease in its two sides and increase at its top and bottom. The condition of the vertical stress is on the contrary. The stress clearly changes with the change of angle in all of the changing area, and the maximal-chief stress changes clearly in the forward cross section. 3 ） When tunnels have the best angle, rock deformation would be relatively small and the maximum principal stress would be around the tunnel periphery. When the tunnels don＇t have the best angle, rock deformation would be relatively large and the maximum principal stress would have a tendency to develop towards the four corners of the tunnel, or towards both the two faces.