西安出露及隐伏地裂缝与地铁隧道相互作用数值模拟分析

A Numerical Simulation of Interactions between Ground Fissures and Xi'an Metro Tunnel

随着西安地铁工程的开展,西安地裂缝对地铁的影响成了亟需解决的重大科学问题。为了更好地反映实际情况,并与出露地裂缝工况下大型物理模型试验对比,建立了穿越出露及隐伏地裂缝两种工况的地铁盾构隧道数值计算模型,并将二者的计算结果进行对比分析。结果表明:隐伏地裂缝影响带比出露地裂缝的影响带的范围及深度都要大得多;出露地裂缝模型边侧地表土体竖向位移主要是由于上下盘土体之间的摩擦产生的,而隐伏地裂缝模型是由于地裂缝上盘土体发生沉降,导致其上覆土体产生变形,边侧地表土体的竖向位移为上下盘土体之间的摩擦及上覆地层的变形导致;出露地裂缝与隐伏地裂缝活动作用下盾构衬砌拱底竖向位移曲线均为"S"形曲线,出露地裂缝活动作用下盾构衬砌变形程度较隐伏地裂缝工况要大。

With the launching of the Xi＇an Subway Engineering,Xi＇an ground fissures have become an urgent important scientific problem need to solve.In order to better reflect the actual situation and compare the result of large-scale physical model tests with ground fissure,this paper established two tunnel numerical simulation models between ground fissure and buried ground fissure.The result shows that： the influence scope and depth is much larger in the buried ground fissure;the soil vertical displacement of the side surface is mainly due to friction between the upper and the lower soil in the ground fissure model;but in the buried model,the displacement is due to soil subsidence resulting in the overlaying soil deformation;The vertical displacements of the shield lining arch in the two models are ＂s＂ curves.But the shield lining deformation degree is much larger in the ground fissure model.