地铁竖井下横通道围岩危险系数演化分析

Evolution Analysis on Danger Coefficient of Surrounding Rock along Cross Passage under Vertical Shaft of Metro System

竖井转横通道在城市地铁建设中经常遇到,施工时易引起横通道坍塌或地表过大沉降。对竖井转横通道开挖进行了三维数值模拟分析。基于多元模型的屈服接近度指标,借助ABAQUS软件提供的自定义变量子程序,实现围岩危险系数的动态显示;并结合工程施工节点,进行围岩危险系数演化分析;最后对所选用的危险系数指标的合理性作了说明。结果表明:所选指标合理;通过对危险系数分布及演化特征的分析,可以指导围岩分区和开挖支护,并可为塑性区演化判断以及围岩稳定性评价提供依据。

A vertical shaft then a cross passage would be often met in the urban metro construction. During the construction period, the roof collapse of the cross passage or the over large subsidence of the surface ground would be occurred. A 313 numerical simulation analysis was conducted on the exca- vation of the vertical shaft and then the cross passage. Based on the yielding approach index of the multi element model, with the references of the self-defined variation subprogram provided by the ABAQUS software,the dynamic display of the surrounding rock danger coefficient could be realized. In combination with the engineering construction node, the evolution analysis was conducted on the danger coefficient of the surrounding rock. Finally an explanation was conducted on the rationality of the danger coefficient index selected. The results showed that the selected index was rational. The analysis on the distribution and evolution features of the danger coefficient could be applied to guide the division,excavation and support of the surrounding rock and could provide the basis to the evolution judgement of the plastic zone and the stability evaluation of the surrounding rock.