昔格达组地层大断面隧道施工工法比选分析

发布时间：2018-09-18 16:28

【摘要】：昔格达组地层是一种分布于我国西南地区的河湖相沉积半成岩,水稳性差,遇水易泥化、崩解,强度大幅度降低,在隧道开挖过程中易产生围岩大变形、初期支护结构开裂、掉块、坍塌冒顶等灾害事故,严重影响着交通隧道工程的建设。以改建铁路成都~昆明线米易~攀枝花段桐梓林隧道为工程背景,运用FLAC3D数值仿真软件,建立5种施工工法模型。从隧道围岩变形时空效应特征角度,对比分析昔格达组地层在不同施工工法中的变形响应。研究结果表明,不同施工工法对隧道拱顶沉降影响最大;当隧道设计预留变形量为10~15cm时,建议优先选择三台阶临时仰拱法;当隧道设计预留变形量为10cm以内时,建议优先选择CRD法;最先行开挖面最大挤出变形量与最先行开挖面面积近似呈线性正相关;采用预留核心或增加较大刚度的临时闭合支撑有利于控制掌子面挤出变形。
[Abstract]:Xigeda formation is a kind of sedimentary semi-diagenesis of lacustrine facies distributed in southwest China, which has poor water stability, is easy to muddy when encountered, collapses, and reduces its strength by a large margin. It is easy to produce large deformation of surrounding rock in the course of tunnel excavation, and the initial supporting structure is cracked. The traffic tunnel construction is seriously affected by the disaster accidents such as falling blocks, collapsing and falling the roof. Based on the reconstruction of Tongzilin Tunnel in Miyi ~ Panzhihua section of Chengdu-Kunming railway line, five kinds of construction method models were established by using FLAC3D numerical simulation software. From the point of view of space-time effect of tunnel surrounding rock deformation, the deformation response of Xigeda formation in different construction methods is analyzed. The results show that different construction methods have the greatest influence on the settlement of the tunnel vault. When the reserved deformation of the tunnel design is 10~15cm, it is suggested that the three-step temporary inverted arch method be preferred, and when the reserved deformation amount of the tunnel design is within 10cm, It is suggested that the CRD method be preferred, that the maximum extrusion deformation of the first cutting face is approximately linear positive correlation with the area of the most advanced excavated surface, and that the temporary closed bracing with reserved core or increasing stiffness is helpful to control the extrusion deformation of the face of the palm.
【作者单位】：河北省交通规划设计院;西南交通大学交通隧道工程教育部重点实验室;
【基金】：国家自然科学基金项目,项目编号51678498 中央高校基本科研业务费专项资金,项目编号SWJTU11ZT33 教育部创新团队发展计划,项目编号IRT0955 原铁道部科技研究开发计划重大课题,项目编号2009.GD20-B 交通运输部西部科技项目,项目编号2013318J13340
【分类号】：U455.4

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