花岗岩地层中既有车站内爆破进洞技术

以厦门轨道交通2号线2标东渡路站~建业路站区间为背景,该区间为暗挖隧道,共有四个暗挖工作面,其中某一工作面位于既有车站结构内,左右线隧道洞口与主体结构为零距离,隧道洞身范围为高强度微风化花岗岩地层,且隧道区间两侧重要建(构)筑物较多,有老旧无基础小区紧邻隧道边,本文结合实际情况对硬岩隧道进洞可选工法进行了比选,阐述了液压式岩石分裂施工、静态爆破剂爆破、二氧化碳气爆、悬臂式隧道掘进机、钻爆法等,最终选取了采用钻爆法进洞,并制定了科学合理的爆破方案,深化了爆破设计,对爆破控制、减震措施、爆破设计参数、防护措施等均做了分析和总结,通过监测数据指导施工,在达到爆破效果的同时又不对车站结构造成任何损伤,最终成功实现了花岗岩地层中既有车站内爆破进洞。

Blasting Technology of Granite Tunnel in Existing Station

Taking the blasting excavation of a certain underground excavation face in the section between Dongdu Road Station and Jianye Road Station of Xiamen Rail Transit Line 2 as the background,there are four subsurface excavation faces,one of which is located in the existing station structure,the entrances of the left and right tunnel are of zero distance from the main structure,and the tunnel body is in the high strength and slightly weathered granite stratum.There are many important buildings on both sides,and old residential areas without pile foundation near the tunnel.In this paper,the excavation methods of hard rock tunnel were compared and selected according to the actual situation.The hydraulic splitter cracking rock,static blasting,carbon dioxide gas explosion,cantilever tunnel boring machine,drilling and blasting method were expounded.Finally,the drilling and blasting method was selected,and a scientific and reasonable blasting scheme was formulated,the blasting design was deepened.The blasting control,shock absorption measures,blasting design parameters and protective measures were analyzed and elaborated in detail.The blasting effect was achieved without any damage to the station structure through monitoring data to guide the construction.The granite tunnel blasting was successfully implemented in the existing station.