黄土隧道双侧壁导坑法施工围岩力学性状及变形界限值  

Mechanical Properties and Deformation Limit Value of Surrounding Rocks in Loess Tunnel Construction by Double-side Heading Method

作　　者：曹谦 陈杰 孙成才 徐作涛 范其明 CAO Qian;CHEN Jie;SUN Chengcai;XU Zuotao;FAN Qiming(China Railway 24th Bureau Group Co.,Ltd.,Shanghai 200433,China)

机构地区：[1]中铁二十四局集团有限公司,上海200433

出　　处：《水利与建筑工程学报》2022年第2期59-65,共7页Journal of Water Resources and Architectural Engineering

基　　金：陕西省自然科学基础研究计划(2019JLM-56)。

摘　　要：黄土特殊的工程性质给大断面黄土隧道设计中围岩变形控制量与预留变形量值的确定带来了困难。本研究以大断面马蹄形黄土隧道为对象,采用FLAC;数值计算软件,建立三维数值模型,依据黄土物理与力学指标,研究了不同支护强度条件下黄土隧道围岩应力、变形变化规律以及拱顶监测变形极限值。结果表明:开挖扰动作用下黄土隧道地层应力由地面到拱顶距离先增大后减小,地层沉降位移随与地面距离增大而增大。隧道拱顶最大沉降随支护模量的减小先缓慢增长,随后迅速增长,不易控制。因此需要找到拱顶沉降加速增长的临界点,对应的极限值作为拱顶沉降的控制条件。由于隧道拱顶最终沉降由掌子面开挖前拱顶沉降和掌子面开挖后可检测出的拱顶监测沉降组成,可结合位移释放率得出监测沉降极限值,确定拱顶监测沉降控制条件。研究成果为黄土隧道围岩稳定性监测提供理论依据。It is difficult to determine deformation control and reserved deformation of surrounding rocks in the design of a large section loess tunnel due to the special engineering properties of loess.In this paper,the finite difference soft-ware FLAC3D was adopted to analyze the large section horseshoe-shaped loess tunnel.According to physical and me-chanical indexes of loess,the surrounding rock and deformation change law and the vault monitoring deformation limit value of loess tunnel under different supporting strength conditions was analyzed.The results show that the stratigraphic stress of the loess tunnel increases first and then decreases from ground to vault,and the stratum settlement displace-ment increases under the excavation disturbance.Maximum settlement of tunnel vault first increases slowly with the de-crease of supporting modulus,and then increases rapidly,which is difficult to control.Therefore,it is necessary to find the critical point for the sped up growth of vault settlement,and we use the corresponding limit value as the control condition of vault subsidence.Since the final settlement of the tunnel vault comprises the dome settlement before tunnel face excavation and can detect the vault monitoring settlement after excavation,the monitoring settlement limit value can be determined by combining the displacement release rate to determine the monitoring settlement of the vault con-trol conditions.The research results could provide a theoretical basis for monitoring the stability of surrounding rock in the loess tunnel.

关 键 词：黄土隧道 地层应力 沉降位移 沉降控制条件 开挖扰动 

分 类 号：U45[建筑科学—桥梁与隧道工程]