上软下硬地层隧洞开挖面极限支护力及变形规律

Study on ultimate supporting force of tunnel excavation face and deformation law in upper-soft lower-hard stratum

确定隧洞开挖面极限支护力最值在隧洞开挖中极为重要。当盾构机通过上软下硬复杂地层时,若隧洞开挖面支护压力控制不当,极易引起隧洞开挖面失稳,对施工安全构成巨大威胁。针对上述状况,采用引入孔隙水压力修正后的计算模式对某盾构隧洞开挖面极限支护力进行了理论计算,并利用数值模拟方法对上述计算结果进行了验证。对复杂地质条件下盾构施工引起的开挖面变形及开挖面前方地表沉降、隆起规律进行了分析。相关成果可为复杂地质条件盾构隧洞开挖面极限支护力最值的确定及安全施工提供依据。

It is very important to determine the ultimate supporting force of tunnel excavation face.When a shield machine goes through a upper-soft and lower-hard stratum,the support pressure of tunnel excavation face is hard to control,which is likely to induce instability of tunnel excavation surface.The ultimate supporting force of a shield tunnel excavation face is calculated by introducing the pore water pressure correction mode,and the above calculation results are verified by numerical simulation method.Finally,the deformation laws of excavation face and the front ground subsidence or uplift caused by shield tunneling are analyzed under complex geological conditions.The results can provide reference for the determination of the maximum value of the ultimate supporting force of shield tunnel excavation face and the safe construction in the complex geological conditions.