引入环向压应力系数的竖井井壁空间被动土压力新解

若采用哈尔-卡门完全塑性准则,则通过简化滑移线法求解的竖井井壁空间被动土压力值偏大,在工程应用中偏于保守。为了更加准确地计算竖井井壁的空间被动土压力值,本文引入一个环向压应力系数,对哈尔-卡门完全塑性准则进行修正,此时井壁围岩微元体上径向正应力最大、环向正应力次之、轴向正应力最小,并针对轴对称竖井围岩被动极限平衡状态开展分析,从而推导了一般环向压应力系数下竖井井壁空间被动土压力计算新解。分析表明：环向压应力系数对竖井井壁空间被动土压力有较大影响,呈现环向压应力系数越大,井壁空间被动土压力值越小的特点。笔者建议在工程应用中,采用环向压应力系数为静止土压力系数的倒数时的竖井井壁空间被动土压力值。

A new solution of spatial passive earth pressure of shaft wall when the tangential stress coefficient is introduced

If Haar-Von Karman complete plasticity criterion is adopted, the value of spatial passive earth pressure of shaft wall solved by simplified slip line method is too large, and it is conservative in engineering application. In order to calculate the spatial passive earth pressure of the shaft wall more accurately, a tangential stress coefficient is introduced in this paper to modify the Haar-Von Karman complete plasticity criterion. At the same time, the radial stress is the largest, the tangential stress is the second, and the axial stress is the smallest. Based on the analysis of the passive limit equilibrium state of the surrounding rock of the axisymmetric shaft, a new solution for calculating the spatial passive earth pressure of the shaft wall under the general tangential stress coefficient is derived. The analysis shows that the tangential stress coefficient has a great influence on the spatial passive earth pressure of the shaft wall, and the larger the tangential stress coefficient is, the smaller the spatial passive earth pressure value of shaft wall is. The author suggests that the spatial passive earth pressure value of shaft wall should be adopted in engineering application when the tangential stress coefficient is the reciprocal of the static earth pressure coefficient.