对佛山软土地区狭长基坑的长边效应进行研究,是保证基坑建设期安全非常重要的一项工作。依托佛山地铁某站狭长深基坑工程实践,结合地下连续墙变形监测数据,开展该类基坑的长边效应分析研究,并利用有限元分析软件进行模拟分析。研究结果表明:狭长型深基坑的长边效应显著存在,主要表现在显著增大基坑长边跨中地下连续墙最大水平位移值,且降低最大水平位移点的深度,对该类基坑的建设期安全极为不利;通过对比实测与模拟分析结果,得出实测位移最大值明显大于模拟值。提出增大基坑长边跨中刚度的方法可减小长边效应的不利影响,能确保建设期安全。

Researching the long side effect of the long and narrow foundation pit in Foshan soft soil area is of great significance for the safety construction of such foundation pits. With the long and narrow foundation pit of a Metro station in Foshan as research background, we simulated the long side effect by finite element software in association with monitoring data of underground diaphragm wall. Results implied that the long side effect of long and narrow deep foundation pit is detrimental to construction safety by increasing the maximum horizontal displacement of underground diaphragm wall in the long side span and lowering the depth of maximum horizontal displacement. The simulation results are relatively conservative, apparently smaller than measured values. Increasing the stiffness at mid-span of the long side of foundation pit could alleviate the long side effect for the safety of construction period.