深圳地铁罗湖站安全线深基坑围护结构设计

根据深圳地铁罗湖站安全线深基坑围护结构周围地理环境、水文地质与工程地质条件和地下结构特点等特征,选择了人工挖孔灌注桩加支撑的基坑支护方案。采用等值梁法,分别计算了5种工况条件下支护桩所受的内力(剪力和弯矩);综合各种工况下内力大小与分布,设计了支护桩的截面、桩长、桩间距和配筋设计计算;对支撑的布置、尺寸进行了设计,对支撑构件的强度和基坑支护体系的整体稳定性进行了检算,包括抗倾覆、抗管涌等。施工实践证明,各支护结构的位移、变形、支撑轴力,周边地面沉降等实测数据都在规范要求之内。

Safe-line Deep Foundation Pit Enclosuring Structure in Shenzhen Metro

In the light of the surrounding hydrogeology,the engineering geology conditions, the underground structure and so on, the hand-dug filling pile and the bracing system are selected as the retaining and protecting measures for foundation excavation. The main design includes the following aspects: by using the equivalent beam method, in which the excavation process is taken into account, the inner force (shear stress and bending moment) of the pile body is calculated under five excavation stages;through analyzing the inner force value and its distribution along the pile body under the condition of various excavation stages, the pile length, the cross section mode, the pile size, the pile distance and the rebars disposition are determined; the four layers, struts, including two layers of soil anchor at the upper pile and two layers of steel propping at the lower pile, their distribution and size are designed and the strength of the bracing is examined; the whole stability to retain and protec the foundation pit is calculated, including the measures against overturning and piping.