中文摘要：

以深圳地铁3号线老街站—晒布路站区间盾构隧道为背景,针对小净距双孔盾构隧道中间夹岩的复杂三维受力状态,引入基于Mohr-Coulomb剪切屈服准则与拉伸屈服准则的屈服接近度函数,采用数值模拟计算和离心模型试验相结合的手段,对上下重叠和水平并行两类小净距隧道中间夹岩力学特征进行了深入研究。研究结果表明,无论是重叠还是并行隧道,其夹岩的中间部分屈服接近度值均大于两侧部分,即中间比两侧相对稳定,但两者的原因侧重点不同,前者侧重于减小应力圆＂半径＂,而后者主要是通过应力圆＂圆心＂外移来相对改善夹岩中间部分的受力状态;对于城市浅埋隧道,在同等静力学条件下,上下重叠隧道夹岩的受力优于水平并行隧道。计算结果可为今后类似工程的设计、超前注浆孔的合理布置提供指导。

英文摘要：

Based on the Laojie-Shaibulu shield tunnels of Shenzhen Metro Line 3,and considering the complicated and three-dimensional stress state in the shared rock of neighborhood tunnels,the yield approach index（YAI） function on the basis of Mohr-Coulomb shear yield criterion and tensile yield criterion is introduced,and two methods,i.e.numerical analysis and centrifugal model test,are employed to analyze the mechanical characteristics of shared rock of the two styles of neighborhood tunnels,which are overlap tunnels and parallel tunnels.The results indicate that YAI value of the middle part is larger than that of the side parts both in the shared rock of the overlap tunnels and parallel tunnels,namely the middle part is relatively far from a failure state compared with the side parts.But the main reason is different.The former is mostly due to the reduction of the ‘radius’ of stress circle,and the latter is mainly due to the move-out of the ‘center’ of stress circle to improve the stress state of the middle part of the shared rock relatively.For shallow buried tunnel,the shared rock of overlap tunnels is in better stress state than that of parallel tunnels under the same static conditions.