红粘土与砂岩夹泥岩接触带隧道合理施工工法研究  

Study on Reasonable Construction Method for Tunnels in Contact Zone of Red Clay and Sandstone Interbedded with Mudstone

作　　者：于介[1] YU Jie(China Railway First Survey and Design Institute Group Co.,Ltd.,Xi′an,710043)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《现代隧道技术》2021年第2期174-181,共8页Modern Tunnelling Technology

基　　金：中国国家铁路集团有限公司科技研究开发课题(2017G007-G).

摘　　要：针对红粘土与砂岩夹泥岩接触带围岩上软下硬、自稳能力差的特点,文章通过现场调研和分析,明确了隧道施工原则,并结合现场实际采用数值模拟计算方法优化了施工工法和支护参数,现场应用效果表明:在红粘土与砂岩夹泥岩接触带地层中施工,岩性分界面位置对隧道变形及结构应力影响明显,随着红粘土在隧道开挖断面的占比增大,隧道洞周位移及初期支护应力显著增大;采取调整台阶高度、取消预留核心土等措施优化施工工法后,最大变形值未超出允许值,初期支护最大压应力未达到材料破坏强度,围岩应力集中减弱,满足安全施工的要求;掘进速度明显提升,避免了岩性分界面位置处围岩易掉块、坍塌等问题。In view of the characteristics of upper-soft and lower-hard rocks with poor self-stability in the contact zone between red clay and sandstone interbedded with mudstone,this paper,by carrying out field investigation and analysis,clarifies the construction principles and optimizes the construction methods and support parameters through the numerical simulation calculation in combination with actual conditions on the site.The field application results show that the position of the lithological interface has an obvious effect on the deformation and structural stress of the tunnel when construction in the contact zone of red clay and sandstone with mudstone,as the proportion of red clay in the excavation section increases,the displacement around the tunnel and the initial support stress in⁃crease significantly;after optimizing the construction method by adjusting the height of benches and cancelling the reserved core soil,the maximum deformation value does not exceed the allowable value,the maximum compressive stress of the initial support does not reach the material failure strength,and the stress concentration phenomenon of surrounding rocks is weakened,meeting the safe construction requirements;the advance rate is significantly in⁃creased,avoiding the problems such as rock falling and collapsing in the lithological interface.

关 键 词：红粘土 砂岩 接触带 隧道 施工工法 开挖支护 

分 类 号：U455[建筑科学—桥梁与隧道工程]