临近地铁隧道加固施工非原位试验分析研究

Non-in Situ Test Analysis of Reinforcement Construction Near Subway Tunnel

上海地铁2号线某地铁上盖项目采用三轴搅拌桩对地铁隧道周围土体进行加固,为测试施工工法对地铁隧道结构的影响,进而优化设计施工参数,施工前进行了非原位试验研究。试验中对三轴搅拌桩施工过程中距桩墙中心1.5~3.0 m范围内的深层土体侧向位移进行了测试。试验结果表明:在三轴搅拌下沉至设计深度时,周边土体变形出现峰值,成桩后3 h变形量值开始回落,成桩后64 h变形基本稳定在1~2 mm,变形深度主要在浅部,施工叠加影响会导致变形影响深度下移。试验结果可为同类工程提供参考。

Triaxial mixing pile was used to reinforce the soil around the subway tunnel of Shanghai Metro Line 2.In order to test the influence of construction method on subway tunnel structure and optimize the design of construction parameters,non-in situ test research was carried out before construction.During the construction of triaxial mixing pile,the lateral displacement of deep soil in the range of 1.5~3.0 m from the center of pile wall was tested.The test results show that when triaxial mixing sinks to the design depth,the deformation of surrounding soil reaches the peak value.The deformation value begins to fall 3 hours after pile completion,and the deformation was basically stable at 1~2 mm at 64 hours after pile completion.The deformation depth was mainly in the shallow part,and the superposition influence of construction would lead to the downward movement of the deformation influence depth.This research could provide reference for similar projects.