简介:钻爆法隧道穿越新建既有双连拱隧道结构,下穿隧道为大跨度隧道,高度大、埋深较深,且在穿越既有隧道时,不能影响其安全运营和造成结构破坏,施工难度大、风险高.采用有限元软件Midas GTS NX对钻爆法隧道下穿既有隧道的变形和受力情况进行数值模拟计算,并研究了下穿施工前对上方隧道间地层采用大管棚和锚杆联合加固产生的效果.研究表明:未加固时,施工侧隧道结构的沉降要大于另一侧,呈现出"一峰二谷"变形形状,既有隧道上下部极易发生结构破坏.采用大管棚及锚杆联合加固,有效地转移了应力集中现象,降低了结构破坏风险,并且既有隧道沉降量仅为前者变化量的 1/1.83,在控制标准以内.Abstract:The drilling and blasting tunnel crosses the newly built existing double-arch tunnel structure.The subway is a large span tunnel,with a large height and deep burial,and when crossing the existing tunnel,it cannot affect its safe operation and structural damage,the construction is difficult.A numerical simulation was carried out using the finite element software Midas GTS NX to calculate the deformation and stresses of a drilling and blasting tunnel underpassing an existing tunnel,and to study the effect of the combined reinforcement of the inter-tunnel strata above using large pipe sheds and anchors before the underpass construction.Studies have shown that the settlement of the tunnel structure on the co..
简介:为解决同赛高速隧道施工中振动风险高、作业面不足、洞身超挖的问题,自主研究开发爆破风险识别程序,基于地质背景与施工条件,采用现场试验、数值模拟、工程实测等方式,开展隧道钻爆布孔形式、装药结构、轮廓线等技术参数优化研究.现场实践表明:通过应用研发振动风险识别程序,可大幅度提高现场振动风险识别、动态控制能力,有效避免了敏感人群、建筑群受扰动风险;依据现场有效作业面设大倾角掏槽布孔,辅以扩槽孔、拱顶单排下压孔等措施,在满足掏槽、破岩要求的前提下达到了提升工效的预期;采用优化周边孔装药结构、收紧拱顶轮廓线等措施,有效降低了洞身排险后超挖量,现场初支喷混超方量由 200%降低至 100%以内,同时每循环节省药量约20kg,经济效益显著.Abstract:To solve the problems of high vibration risk,insufficient working surface and over-excavation in the construction of the Tongren-Saierlong Expressway Tunnel,the blasting risk identification program is independently developed.Based on the geological background and construction conditions,field tests,numerical simulation,engineering measurement.were adopted to carry out the optimization of technical parameters such as tunnel drilling and blasting hole layout,charge structure and contour line.The field practice shows that the application of the developed vibration risk identification program can greatly improve the ability of vibration risk identification and dynamic control and effectively...