地铁隧道全断面注浆对地表隆起影响分析

Influence of Full-face Grouting of the Metro Tunnel on Ground Surface Heaving

  • 摘要: 深圳地铁某隧道暗挖段由于高强度注浆导致地表持续隆起,最大值超过50 cm,且后续开挖过程中地表并无沉降现象发生。考虑到该区段内主要为砂卵石地层,上部与底部分别为少量粗砂和全风化花岗岩复合地层,文章采用理论分析、数值模拟和现场实测手段,从注浆抬升角度对已发生的地表隆起现象进行原因分析。结果表明:从注浆效果来看,注浆对该段松散土体产生渗透压密效果,并在较大的注浆压力作用下产生水力劈裂;劈裂注浆浆液脉络方向多为水平;注浆区两侧旋喷桩的施作改变了注浆地层原有的应力状态,加强了地表隆起程度。

     

    Abstract: Continuous heaving of ground surface occurs at certain mined section of Shenzhen metro due to high in? tensity grouting, with the maximum heaving exceeds 50 cm and no settlement occurrence during the subsequent tunnel excavation. Considering that it mainly consists of sandy cobbles and little coarse sand and fully weathered grani?telocated at the upper part and bottom,an analysis on the causes of ground surface heaving is conducted by theoretical analysis, numerical simulation and field measurement from the aspect of lifting by grouting.The results show that grouting has penetration compaction effect on the loose soil mass of this section and hydraulic fracture occurs under large grouting pressure; the directions of most grouting veins are horizontal;jet grouting pile constructed on the both side of grouting area changes the initial stress state of grouted stratum and increases the degree of ground surface heaving.

     

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