基于断裂力学的卸荷带岩质边坡稳定性研究  

The Stability Analysis of Rock Slide in the Unloading Crack Zone Based on Fracture Mechanics

作　　者：王栋[1] 陈国庆 米冠宇 张广泽[1] WANG Dong;CHEN Guoqing;MI Guanyu;ZHANG Guangze(China Railway Eryuan Engineering Group Co.Ltd,Chengdu,Sichuan 610031,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu,Sichuan 610051,China)

机构地区：[1]中铁二院工程集团有限责任公司,成都610031 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610051

出　　处：《铁道工程学报》2020年第6期24-30,共7页Journal of Railway Engineering Society

基　　金：国家自然科学基金资助项目(41972284);中铁二院工程集团有限责任公司科研项目〔KYY2019066(19-20)〕。

摘　　要：研究目的:川藏铁路沿线存在大量的卸荷带岩质边坡,边坡发生失稳坡坏会对铁路和人民生命财产安全造成损害,因此有必要对卸荷带岩质边坡的稳定性进行研究。本文基于断裂力学理论,对边坡进行力学模型概化,运用最大周向应力断裂准则进行分析,并推导出裂隙水压力和重力共同作用下边坡稳定性系数计算公式,利用该公式分析结构面几何参数对边坡稳定性的影响及裂纹扩展方向变化规律。研究结论:(1)边坡稳定性系数随裂纹角的变化存在峰值,随平均高度的增大呈上升趋势,随裂隙长度的增加呈下降趋势;(2)结构面几何参数不同,则裂纹尖端附近的应力应变情况不同,复合应力强度因子不同,裂纹扩展方向也不同,裂纹角越大,平均高度越小,裂纹越来越趋向于边坡坡面扩展;裂隙长度和裂纹扩展方向无关;(3)通过对卸荷带岩质边坡的断裂力学机制和稳定性进行分析,可为该典型边坡的评价提供理论支持。Research purposes: There are a lot of rock slopes in unloading zone along Sichuan-Tibet Railway. The failure of rock slopes will damage the safety of railway and people’s lives and property. Therefore,it is necessary to study the stability of rock slopes in unloading zone. Based on the theory of fracture mechanics,the mechanical model of slope is generalized,and the maximum circumferential stress fracture criterion is used to analyze the slope stability. The formula for calculating the slope stability coefficient under the joint action of crack water pressure and gravity is derived.The influence of geometric parameters of structural plane on slope stability and the variation law of crack propagation direction are analyzed by the formula.Research conclusions:( 1) There is a peak value of slope stability coefficient with the change of structural plane dip angle,which increases with the increase of average height and decreases with the increase of crack length.( 2) The stress and strain near the crack tip are different when the geometrical parameters of the structural plane are different. The composite stress intensity factors are different and the direction of crack propagation is also different. The larger the inclination angle and the smaller the average height of the structural plane,the more the crack tends to propagate on the slope;the length of the crack has nothing to do with the direction of the crack propagation.( 3) By analyzing the fracture mechanics mechanism and stability of rock slope in unloading zone,the theoretical support can be provided for the evaluation of the typical slope.

关 键 词：卸荷带边坡 断裂力学 裂隙水压力 稳定性 

分 类 号：P642.4[天文地球—工程地质学]