变坡面浅埋偏压小净距隧道围岩压力计算方法

Calculation Method of Surrounding Rock Pressure of Variable Slope Surface Shallow Buried Bias and Small Clear Distance Tunnel

为研究在考虑黏聚力和内摩擦角作用下对变坡面浅埋偏压小净距隧道围岩压力的影响,本文利用极限平衡法来求解变坡面浅埋偏压小净距隧道深、浅埋侧侧压力系数、围岩拱顶垂直压力和围岩两侧水平压力,推导出考虑黏聚力和内摩擦角的围岩压力计算方法,通过简单算例与已有规范公式和既有文献进行对比,验证本文公式的合理性,并探讨了深埋侧隧道水平侧压力系数影响因素。结果表明:水平侧压力系数随坡角的增加而逐渐增大,随夹角的增加而呈现不同的变化趋势,随黏聚力和内摩擦角的增加而逐渐减小,随埋深的增加而逐渐增加。在考虑黏聚力和内摩擦角的作用下,本文公式有利于考虑降雨等环境因素引起的岩土体力学参数的变化带来的对围岩不利影响,可为类似变坡面浅埋偏压小净距隧道结构设计和支护参数优化提供理论依据。

In order to study the influence of cohesion and internal friction angle on the pressure of the surrounding rock of the shallow buried bias and small clearance tunnel of variable slope surface,the limit equilibrium method is used to solve the problem of shallow buried bias and small clear distance tunnel depth,shallow buried side pressure coefficient,The vertical pressure of the surrounding rock vault and the horizontal pressure on both sides of the surrounding rock are deduced,and the calculation method of the surrounding rock pressure considering the cohesion and internal friction angle is derived,and the rationality of the formula is verified by a simple example compared with the existing standard formula and the existing literature,and the influencing factors of the horizontal lateral pressure coefficient of the deep buried tunnel are discussed.The results show that the horizontal lateral pressure coefficient increases gradually with the increase of slope angle,shows different trends with the increase of the included angle,decreases with the increase of cohesion and internal friction angle,and gradually increases with the increase of burial depth.Considering the action of cohesion and internal friction angle,the formula proposed in this paper is conducive to considering the adverse effects of the changes in the mechanical parameters of the rock and soil bodies caused by rainfall and other environmental factors on the surrounding rock,which can provide a theoretical basis for the structural design and optimization of supporting parameters of the shallow buried bias and small clearance tunnel with similar variable slope surface.