大断面黄土隧道破坏模式离散元分析  

DEM analysis of failure modes of surrounding rock for large-section loess tunnel

作　　者：扈世民[1] 张顶立[1] 

机构地区：[1]北京交通大学隧道及地下工程实验研究中心,北京100044

出　　处：《北京交通大学学报》2013年第4期13-18,共6页JOURNAL OF BEIJING JIAOTONG UNIVERSITY

基　　金：铁道部科技研究开发计划重大项目资助(2009G005)

摘　　要：以大断面黄土隧道为背景,采用颗粒流程序PFC2D对黄土围岩破坏模式进行研究,再现黄土围岩破坏全过程,综合分析塌落拱与压力拱的发展过程.结果表明:离散元分析与现场实际围岩破坏模式基本吻合;对于黄土围岩,随着荷载逐渐增大,拱部先出现破坏,同时破坏向拱脚蔓延,初始塌落拱出现,塌落拱进一步向围岩深部发展;埋深为影响塌落拱发展关键因素,当埋深较小时,形成蔓延至地表的贯通性裂缝甚至塌陷坑,当埋深足够大时形成稳态塌落拱,与普氏理论类似;压力拱发展与塌落拱相对应,隧道形成稳态塌落拱,同时围岩压力拱亦达到稳定,且拱部压力拱范围扩展较快,反之,即为破坏延伸至地表,无法形成压力拱.Taking large-section loess tunnel as the project background, DEM analysis has been performed for studying the failure modes of loess surrounding rock systematically. The whole failure process has been undermined and the dynamic development process of the collapse and pressure arch have been comprehensive researched. The results are as follows. The failure mode of DEM analysis is consistent with the engineering practice basically. For loess surrounding rock in the process of step loading, failure first occurs on crown and the initial materials collapse arch is appeared, meanwhile failure is spread to the arch spring. The collapse arch is developed to the depth of the surrounding rock. The buried depth is the key factor for the development of the collapse arch. When the depth is small, the cracks or collapse pit which spread to the surface have appeared. When the depth is large enough, a steady collapse arch has arise finally which is similar to the Platts theory. The development of pressure arch is consisted with collapse arch, pressure arch is reaching steady state while also the collapse arch. When the pressure arch extends rapidly, on the contrary, the damage extends is to the surface, the pressure arch can not form.

关 键 词：隧道 大断面 黄土 破坏模式 塌落拱 压力拱 

分 类 号：U452.2[建筑科学—桥梁与隧道工程]