盖挖逆作地铁换乘车站施工力学数值模拟

NUMERICAL SIMULATION OF SUBWAY INTERCHANGE STATION CONSTRUCTED BY TOP-DOWN CONSTRUCTION METHOD

文中以某大型地铁换乘车站盖挖逆作法施工为例,采用增量法建立数值模型,对施工全过程进行模拟计算,研究施工过程中结构内力变化情况,并与总量法计算结果进行对比分析。研究结果表明,盖挖逆作施工过程中,地铁车站结构内力在施做底板之前达到最大值,此时为结构最不利工况;地连墙和中板相交节点处存在较大的负弯矩,应控制地连墙截面设计;增量法和总量法计算结果在内力值和弯矩分布模式上均存在较大差异,且增量法计算结果多数大于总量法;顶板和地连墙连接处为铰接连接,顶板跨中存在较大的正弯矩,往往控制顶板截面设计。

Taking the top-down construction method of a large subway transfer station as the case,the numerical model of the whole construction process is established by using the incremental method to study the changes of structural internal force in the construction process.The results show that the internal force of subway station structure reaches the maximum before the construction of bottom slab,which is the most unfavorable working condition of the structure.In addition,there is a large negative moment at the intersection of the diaphragm wall and the middle plate,so the section design of the diaphragm wall should be controlled.Furthermore,the calculation results of incremental method and total method are quite different in internal force value and bending moment distribution mode,in which the most of the calculation results of incremental method are greater than that of total method.In addition,the joint between the roof and the diaphragm wall is hinged,and there is a large positive bending moment in the roof span,which often controls the design of the roof section.