基于3DEC模拟的高地应力水平层状隧道围岩变形破坏特征分析  

Analysis on Deformation and Failure Characteristics of Surrounding Rock in Horizontal Layered Tunnels under High Crustal Stress Based on 3DEC Simulation

作　　者：王亚琼[1,2] 杨强 潘红伟[3] 高启栋 张士朝 王志丰 WANG Yaqiong;YANG Qiang;PAN Hongwei;GAO Qidong;ZHANG Shichao;WANG Zhifeng(School of Highway,Chang'an University,Xi′an 710064;Shaanxi Provincial Key Laboratory of Highway Bridges and Tunnels,Chang′an University,Xi′an 710064;The First Engineering Co.,Ltd.of China Railway Beijing Engineering Group,Xi′an 710119)

机构地区：[1]长安大学公路学院,西安710064 [2]长安大学陕西省公路桥梁与隧道重点实验室,西安710064 [3]中铁北京工程局集团第一工程有限公司,西安710119

出　　处：《现代隧道技术》2022年第4期127-136,146,共11页Modern Tunnelling Technology

基　　金：国家自然科学基金面上项目(No.52178310);陕西省自然科学基础研究计划资助项目(2021JQ-258);中央高校基本科研业务费专项资金(No.300102210123)。

摘　　要：为深入研究高地应力环境下水平层状隧道围岩变形破坏特征,以云南昭乐高速轿顶隧道为工程背景,分析了现场地应力测试结果与围岩变形破坏情况,采用三维离散元(3DEC)数值模拟方法,分别研究不同岩层厚度d、地应力水平s及侧压力系数k条件下隧道围岩变形与破坏规律,并对水平层状隧道围岩的受力特征及变形破坏机理进行探讨。结果表明:水平层状围岩变形沿隧道中轴线对称分布,节理方向与隧道轮廓相切处围岩位移最大,节理方向与隧道轮廓正交处围岩位移最小;随着层厚的增加,隧道围岩位移量逐渐减小,厚度在0~0.3 m时位移变化较快,超过0.3 m时变化减缓,当层厚达到3.0 m时位移量基本趋于稳定;随着地应力水平的增大,隧道围岩位移量逐渐增大,且变化速率保持稳定;随着侧压力系数的增大,隧道围岩位移量逐渐增大,且拱腰处位移增大最为显著。在高地应力环境下,若围岩层状节理发育,即便岩石本身强度较大,仍有可能发生强烈的挤压变形,表现出软岩大变形的特征。In order to thoroughly study the characteristics of deformation failure in surrounding rock of horizontal layered tunnels under high crustal stress environment, the crustal stress test results and the deformation failure of surrounding rock were analyzed based on engineering background of Yunnan Zhaotong-Leshan Expressway Jiaoding Tunnel. The 3D discrete element(3DEC) numerical simulation method was adopted to study the deformation failure laws of surrounding rock under the conditions of different rock thickness d, crustal stress level s and lateral pressure coefficient k. Moreover, the stress characteristics and deformation failure mechanism of surrounding rock of horizontal layered tunnel were discussed as well. The results show: the deformation of horizontal layered surrounding rock is symmetrically distributed along the central axis of the tunnel. The displacement of surrounding rock is the largest where the joint direction is tangent to the tunnel contour, but is the smallest where the joint direction is orthogonal to the tunnel contour;With the increase of layer thickness, the displacement of surrounding rock of the tunnel decreases gradually. The displacement changes faster when the thickness is 0~0.3 m, slows down when the thickness exceeds 0.3 m, and basically tends to be stable when the layer thickness reaches 3.0 m;The displacement of tunnel surrounding rock increases gradually with the increase of crustal stress, and the change rate remains stable;The displacement of tunnel surrounding rock increases gradually as function of lateral pressure coefficient, and the displacement change is the most significant at the arch waist. In the high crustal stress environment, severe compression deformation may occur even if rock strength is great, in case the layered joints of the surrounding rock are developed, which shows the characteristics of great deformation in soft rock.

关 键 词：高地应力 水平层状围岩 岩层厚度 地应力水平 侧压力系数 3DEC模拟 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]