地道基坑中的小导管墙内撑复合支护计算方法

Analysis Method for a Small Diameter Perforated Pilot Pipe Grouting Technique in the Excavation of a Pedestrian Underpass Tunnel

以武汉市武胜东街人行地下通道梯(坡)道基坑工程为例,介绍了小导管墙内支撑复合支护方案,提出了支护结构的设计计算方法。计算表明,必须考虑钢筋网喷射混凝土面层的竖向抗弯作用,支护结构才能满足竖向抗弯承载力要求,其中型钢与面层可以按钢骨混凝土梁计算其截面受弯承载力;必须考虑基坑底部的封底加固作用,支护结构的抗隆起稳定性才满足规范要求。该计算方法对小导管墙内撑复合支护技术在基坑支护工程中的应用和推广提供了有益的参考。

The support system for the excavation of the pedestrian underpass ramp at Wusheng Road East in Wuhan used the small diameter perforated pilot pipe grouting composited supporting technique.The supporting structure analysis method of the small diameter perforated pilot pipe grouting inside the excavation wall is introduced in this paper.The analytical results indicate that bending resistance of the wire-mesh shotcrete wall in the vertical direction has to be considered in order to meet the bending demand.Among the bending resistance,the rolled steel and the shotcrete facing can be analyzed as the reinforced concrete element.The strengthening effect at the bottom of the excavation also needs to be considered in order to meet the requirements on the preventing of the bottom heaving.