复杂场地盾构区间隧道块石探查和处理技术

The Technology of Block Stone Detection and Treatment for Shield Tunnel in Complex Site

研究目的:覆盖层中存在的块石群对地铁区间盾构施工造成很大影响。采用常规的钻探或物探手段探查块石群的效果较差,选择合适的探查手段及清障技术是类似工程的主要难点。本文以杭州地铁7号线吴山广场站—江城路站区间为依托,系统介绍在复杂场地条件下覆盖层中块石的综合探查技术,分析基于超前注浆加固和爆破预处理的地铁盾构隧道块石清障相关技术。研究结论:(1)在大量既有地表建筑物的条件下,探查块石需要钻孔与物探结合的手段;(2)微动探测在覆盖层中探测块石具有比较明显的优势;(3)在有条件的场地采用爆破预处理,在不具备爆破场地条件下可能遇块石时采用超前注浆加固预处理,盾构掘进通过后采用长管注浆加固管片周围土体,必要时进行带压进仓清理;(4)本研究成果可为类似复杂场地条件下盾构隧道工程的勘察、设计与施工提供参考。

Research purposes:The presence of boulder clusters in the overburden layer has a significant impact on shield tunneling construction for subway sections.Conventional drilling or geophysical exploration methods are not very effective in investigating boulder clusters,and selecting appropriate exploration methods and clearance techniques is a major challenge for similar projects.Based on the section from Wushan Square Station-Jiangcheng Road Station of Hangzhou Metro Line 7,this paper systematically introduced the comprehensive exploration technology of block stones in the overburden under complex site conditions,and analyzed the related technologies of block stone removal for subway shield tunnels based on advanced grouting reinforcement and blasting pretreatment.Research conclusions:(1)Under the condition of a large number of existing surface buildings,it is necessary to combine drilling with geophysical prospecting for the detection of block stone.(2)Microtremor detection has a distinct advantage in detecting boulders in overburden layers.(3)The blasting pretreatment shall be adopted in the site with conditions,and the advanced grouting reinforcement pretreatment shall be adopted in case of encountering block stones in the absence of blasting site conditions.After the shield tunneling,the soil around the segment shall be reinforced by long pipe grouting.If necessary,the warehouse should de cleaned under pressure.(4)The research results can provide reference for the investigation,design and construction of shield tunnel engineering under similar complex site conditions.