隐伏正断层运动下盾构隧道结构力学响应分析

Mechanical Response Analysis of Shield Tunnel Structure under Hidden Normal Fault Movement

文章以济南地铁断层破碎带上部建成盾构隧道为工程背景,考虑管片接缝非线性力学行为、混凝土塑性损伤力学行为及地层-结构接触力学行为,建立盾构隧道跨越隐伏断层数值模型。首先,与已有试验结果进行对比验证了数值模型的合理性,进而研究了隐伏正断层错动下盾构隧道结构力学响应规律,得到盾构隧道环缝接头变形量、管片所受地层荷载分布、管环结构损伤及横向收敛变形与断层错动量的关系,分析隧道周围地层受力状态与隧道结构力学响应变化规律,提出了断层运动下盾构隧道结构典型失效模式。研究表明:隐伏正断层错动下,在断层顶部投影面附近管片环缝产生明显张开及错台,该处管片所受地层荷载及管环横向收敛变形均发生显著突变;管片受拉及受压损伤最大值分别位于拱底内侧及拱腰内侧;盾构隧道结构典型失效模式可分为两个阶段,即环缝接头漏水阶段及管环结构压溃阶段。

With the shield tunnel built in the upper part of the fault fracture zone of Jinan Metro as the engineering background,a numerical model of shield tunnel crossing hidden faults is established in this paper,which takes the nonlinear mechanical behavior of segment joints,plastic damage mechanical behavior of concrete and stratumstructure contact mechanical behavior into consideration.First,the rationality of the numerical model is verified by comparing with the existing test results,and then the mechanical response law of shield tunnel structure under the dislocation of hidden normal fault is studied.The relationship between the deformation of circumferential joints of the shield tunnel,the distribution of stratum load on segments,the damage of segment ring structure,the transverse convergence deformation and the fault dislocation is obtained,the stress state of the stratum around tunnel and the variation law of the mechanical response of tunnel structure are analyzed,and the typical failure mode of shield tunnel structure under fault movement is proposed.The research shows that under the dislocation of the hidden normal fault,the segment circumferential joints near the projective plane of the top of the fault has obvious opening and dislocation,and there is a significant abrupt change in the stratum load on segments and the transverse convergence deformation of segment rings;the maximum tensile and compressive damage of segments are located at the inner side of arch bottom and the inner side of hance,respectively;and the typical failure mode of shield tunnel structure can be divided into two phases,namely,the circumferential joint leakage phase and the segment ring structure collapse phase.