围岩强度对隧洞安全系数和加速度的影响研究

Influence of surrounding rock strength on safety factor and acceleration of tunnel

将基于加速度稳定分析思路用于地下隧洞,可以采用与边坡极限平衡法类似方法计算隧洞的最大加速度和安全系数。对不同围岩强度的圆形隧洞进行稳定分析,并且比较不同支护条件的影响。计算结果表明:对于围岩性质均匀的圆形地下隧洞,其最危险的位置在洞壁上,计算结果与点安全系数的数值非常接近,表明了基于加速度的方法能够用于地下隧洞的稳定分析。对于不同强度围岩的圆形地下隧洞,其加速度和安全系数随距隧洞中心距离变化而变化的趋势大致相同。采用不同厚度的衬砌进行支护,围岩整体的稳定性得到提升。支护结构具有一定的影响范围,衬砌结构越厚,影响范围越大,表明本文的方法能够定量评价结构的支护效果。

The idea of stability analysis based on acceleration is applied to tunnels,and the maximum acceleration and the safety factor of tunnels are then calculated in the same way with the limit equilibrium as in slopes.The stability analysis of circular tunnels with different surrounding rock strength is carried out,and the influence of various support conditions is compared.The calculation results show that,for a circular tunnel with homogeneous surrounding rock properties,the most dangerous position is on the wall.The calculated safety factor on the wall is very close to the point safety factor,which indicates that the acceleration method is suitable for stability analysis of tunnel.For a circular tunnel with different surrounding rock strength,the variation trends of the acceleration and safety factor with the distance from the tunnel center are similar.The general stability of tunnel is improved when the lining with different thickness is adopted.The supporting structure has an influence range.The thicker the lining is,the larger the influence area is.The results show that the method introduced in this paper could quantitatively estimate the effect of supporting structure.