黄土-泥岩交界区隧道衬砌受力及围岩破坏模式分析OACSTPCD

In order to study the mechanical characteristics of tunnel lining and failure mode of surrounding rock in loess-mudstone junction area,taking a tunnel as the engineering background,the lining stress is analyzed by field monitoring and numerical simulation.The results show that:(a)the surrounding rock pressure is concentrated in the inverted arch,and the maximum value appears at the right arch foot;(b)the stress of the outer steel arch is mainly concentrated in the arch shoulder near the interface;(c)the stress of steel arch and the strain of the secondary lining concrete are greatly affected by the development of concrete strength,in which,the concrete and arch are subjected to large compressive stress at the initial stage of lining construction,and with the gradual formation of concrete strength,the stress gradually decreases and tensile stress appears at the inverted arch;(d)the plastic zone of surrounding rock is mainly at the arch shoulder and inverted arch near the interface;and(e)the groundwater flows through the broken surrounding rock along the side wall and gathers in the inverted arch,and the plastic zone of the base mudstone is easy to expand.The research results can provide some references for the design and construction of tunnels in similar boundary strata.