岩石隧道塑性位移新解

 在统一强度理论和弹脆塑性模型的基础上，考虑塑性区围岩弹性模量的变化、中间主应力效应、围岩应变软化和剪胀等影响，推导了深埋圆形岩石隧道塑性位移新解。文中的隧道位移新解具有广泛的理论意义，可根据具体工程实际情况，进行多种合理选择。经工程算例分析可知，由塑性区半径相关的弹性模量计算得到的位移处于上、下限之间，反映了隧道开挖卸荷扰动影响的距离变化，更符合隧道变形真实情况，并得出统一强度理论参数和剪胀特性参数对塑性区位移的影响规律。研究结果表明：隧道塑性区位移受中间主应力、围岩剪胀特性和塑性区弹性模量的影响显著，三者相互影响，共同作用。

NEW PLASTIC SOLUTION FOR DISPLACEMENT OF ROCK TUNNELS

Based on the unified strength theory and the elastic-brittle-plastic model，the new plastic solution for displacement of deep circular tunnels in rock is deduced. The influence of the elastic modulus variation in the plastic zone，intermediate principal stress，rock softening and shear dilation is all involved in this new formula. The new displacement solution obtained in this paper has a broadly theoretical meaning. More reasonable choices could be made according to the actual engineering situations. By analyzing an engineering case，the tunnel displacement calculated with the radius-dependent Young?s modulus is between the upper and lower bounds，which reflects the distance changes of the tunnel excavation unloading affect and is more consistent with the true situation of tunnel deformation. The effects of the unified strength theory parameter and shear dilation characteristic parameter on the tunnel displacement in the plastic zone are discussed. It is shown that the intermediate principal stress，shear dilation and the elastic modulus in the plastic zone have a significant effect on the tunnel plastic displacement，in which these three aspects influence each other and work together.