砂层地段土压平衡盾构施工技术探讨

广州地铁盾构区间部分穿越陆相洪积—冲积砂层及河湖相淤泥质、粉质黏土层，砂性土层内摩擦角大，渣土流动性差。排土困难，地下水压高时，易发生喷涌现象，因此砂层盾构掘进控制困难，易造成地表沉降。以广州地铁3号线“珠江新城站—客村站”区间圆形盾构隧道工程实践为例，探讨土压平衡盾构穿越砂层地质的施工技术。

Construction Technique of Shielding the Sand Bed with Soil Pressure Balance

The shield construction of Guangzhou Subway comes through the terrestrial proluvial and alluvial placer and lacustring silt and clay. The friction angle in the sand bed is big and the fluidity of the residued sand is bad, which causes difficulty in dischaging the sludge. With the high underground water pressure it is vuneral to the outblow. Therefore, the sand bed shield tunneling is very difficult to control, and possible to cause land settlement. The round shield tunnelling construction in the section from Zhujiang New Village Station to Kecun Station of the No. 3 Guangzhou Subway has been illustrated as an example and the construction technique of soil pressure balane shield tranversing the sand bed has been studied.