薄层状岩体隧道冒顶机制及支护方案优化研究
Study on Roof Caving Mechanism and Support Scheme Optimization of Tunnels in Thin-bedded Rock Mass
魏传文 1王相龙 1杨旭旭 2赵玉棣 1邵行 3满新杰 1张长安 3周洋洋 1张作顺2
作者信息
- 1. 山东高速基础设施建设有限公司,济南 250101
- 2. 山东科技大学土木工程与建筑学院,青岛 266590
- 3. 山东省交通规划设计院集团有限公司,济南 250101
- 折叠
摘要
以山东省临淄—临沂高速公路曹家顶隧道为工程背景,采用三维离散元数值计算软件3DEC建立分析模型,探究薄层状岩体条件下隧道冒顶机理.通过拱顶岩体离层监测及塑性区分析,指出原有锚杆支护体系无法有效控制冒落高度是造成拱顶冒落的根本原因.据此,提出锚索支护方案并进行支护参数优化分析,包括不同锚索长度、顶板锚索根数及边墙锚杆数量比3个参数.通过对数值计算结果进行分析,确定顶板范围内施作5根锚索,长度为5.5 m,边墙锚杆数量比0.5的锚索支护优化方案.选取具有冒顶风险的隧道区间开展锚索支护试验,监测数据显示,试验断面锚索平均轴力值比常规断面同位置处锚杆平均轴力值在拱肩下、拱肩上、拱顶位置分别提高65.1%、31%和8.5%,说明锚索支护体系相比锚杆支护体系可有效控制拱顶冒落.
Abstract
With the Caojiading Tunnel on Linzi-Linyi Expressway in Shandong being used as an example in this study,the three-dimensional discrete element numerical calculation software 3DEC is used to create the analysis model,in order to investigate the roof caving mechanism of a tunnel in thin-bedded rock mass.Through roof separa-tion monitoring and plastic zone analysis of the crown rock mass,it is determined that the root cause of crown roof caving is the fact that the original rockbolt support system fails to effectively control the roof caving height.On this basis,the anchor cable support scheme is proposed and the support parameters are optimized and analyzed.3 variables are analyzed,including various anchor cable lengths,number of roof anchor cables and side wall rockbolt quantity ratio.According to the numerical calculation,the optimized anchor cable support scheme is selected,where there are 5 anchor cables which are 5.5 m long in the scope of the roof and the side wall rockbolt quantity ratio is 0.5.A tunnel section with the risk of roof caving is selected to conduct the anchor cable support test.According to analysis of the monitoring data,the average axial force of anchor cable at the tested section is increased by 65.1%,31%and 8.5%at the position below the spandrel,at the position above the spandrel and at the crown as compared with the average axial force of rockbolt at the same positions in the common section.This indicates that anchor cable support system can control crown roof caving more effectively than rockbolt support system.
关键词
薄层状岩体/冒顶灾害/3DEC数值模拟/锚索支护/现场监测Key words
Thin-bedded rock mass/Roof caving disaster/3DEC numerical simulation/Anchor cable support/Site monitoring引用本文复制引用
出版年
2024
NETL
NSTL
万方数据