微型桩与帷幕的不同位置对复合土钉墙力学性状的影响分析

基坑工程中微型桩和止水帷幕的复合土钉墙是常用支护结构型式之一。在支护结构设计和施工时布置微型桩与帷幕的位置具有随意性，普遍忽视微型桩在帷幕内外不同位置对于支护结构力学性状的影响。依托济南某基坑工程，通过现场测试和数值模拟的对比分析，获得微型桩在帷幕内外两种位置条件下支护结构位移、土钉内力等变形及受力特征。分析结果表明，微型桩的位置不影响支护结构变形和内力的总体趋势；无坡顶荷载时，微型桩位置不同产生的差别不大；存在坡顶荷载时微型桩位于帷幕内侧时支护结构变形较小，土钉受力更合理，建议实际工程优先采用。

Impact of position of micro pile on mechanical behaviors of composite soil nailing wall curtain

Composite soil nailing wall composed by micro-pile and waterproof curtain is a frequently used type of supporting structure in foundation pit engineering. But the collocation of micro-pile and waterproof curtain in the design and construction of supporting structure is random. And the influence of different locations of micro-pile, like in front of or behind curtain, on mechanical behaviors of supporting structure is generally neglected. This article obtains deformation and mechanical characteristics, such as the displacement of supporting structure, axial force of soil nailing, in those two collocations through the contrastive analysis of the field test and numerical simulation based on a certain foundation pit project in Jinan. The analysis results show that the overall trend of deformation and internal force of supporting structure isn’t affected by different location of micro pile. And the difference caused by the location of micro-pile without top load is small; but the deformation of supporting structure is smaller and the stress of soil nail is more reasonable when micro pile is behind curtain under top load. And it can be suggested to preferentially adopt in practical engineering.