考虑松动圈影响的公路隧道大直径竖井围岩压力计算方法

Calculation Method for Surrounding Rock Pressure of Large Diameter Vertical Shaft in Highway Tunnel Considering the Influence of Loosening Circle

为研究公路隧道大直径竖井围岩压力计算方法,基于极限平衡法推导,并与官田竖井实测数据进行了对比验证,最后分析了竖井直径、侧压力系数、围岩等级对竖井围岩压力的影响规律。结果表明:①与实测数据对比结果显示,本文公式的平均误差度在12.85以内,相比其他公式的误差度在180以上,使相对误差减小了167.15以上,可指导工程人员进行竖井的施工设计;②竖井开挖直径越大,竖井井壁围岩压力越大,但是围岩压力的增长幅度随直径增大而逐渐减弱;③在未达到极限深度之前,侧压力系数越大,竖井井壁围岩压力越大;达到极限深度以后,不同侧压力系数下井壁的围岩压力一样大。侧压力系数越大,井壁围岩压力随竖井深度的增长越大,更快达到最大井壁围岩压力,即极限深度越小;④围岩等级越高,竖井的井壁围岩压力越小,在达到极限深度之后的围岩压力也越小。

In order to study the calculation method of surrounding rock pressure of large diameter shaft in highway tunnel,based on the limit equilibrium method derivation,and compared with the measured data of Guantian shaft,the influence of shaft diameter,lateral pressure coefficient,and surrounding rock grade on the surrounding rock pressure of shaft was analyzed.The results show these as follows.Compared with the measured data,the average error of the formula in this article is within 12.85,while the error of other formulas is above 180,reducing the relative error by more than 167.15.This can guide engineering personnel in the construction design of vertical shafts.The larger the excavation diameter of the shaft,the greater the surrounding rock pressure on the shaft wall,but the increase in surrounding rock pressure gradually weakens as the diameter increases.Before reaching the limit depth,the greater the lateral pressure coefficient,the greater the surrounding rock pressure of the shaft wall,after reaching the limit depth,the surrounding rock pressure of the shaft wall is the same under different side pressure coefficient.The greater the lateral pressure coefficient is,the greater the wall rock pressure increases with the shaft depth,and the faster it reaches the maximum wall rock pressure,that is,the smaller the limit depth.The higher the level of surrounding rock,the lower the pressure of the surrounding rock on the shaft wall,and the lower the pressure of the surrounding rock after reaching the limit depth.