摘要
非贯通节理岩体的强度特性是大型边坡、隧道等工程安全性的重要影响因素。随着酸雨、河流污染等对岩石环境劣化程度的加剧,考虑环境劣化因素对非贯通节理岩体强度的影响很有必要。采用离散元法,基于已有的胶结接触模型,将岩体因环境作用而劣化等效为岩石试样质量损失不断加剧的过程,最后等效为颗粒和颗粒之间的物质不断溶蚀的过程,由此建立考虑环境劣化的微观接触模型并将其植入离散元软件中,模拟分析了不同环境劣化程度的非贯通节理岩体在不同连通率和不同法向应力下的直剪试验。结果表明:不同环境劣化程度非贯通节理岩体剪切应力-位移曲线趋势一致;随环境劣化程度的加深,节理岩体的破坏形式以拉裂纹为主转变为以剪切裂纹为主;环境劣化使得节理岩体直剪试验起裂应力降低,且环境劣化程度的加深会导致非贯通节理岩体的凝聚力降低及内摩擦角减小,表现为峰值剪切强度降低。
The strength property of the intermittent jointed rock mass is an important factor which affects the safety of large slope and tunnels.With the increasing degree of environmental degradation induced by the acid rain,pollution and other factors,it is necessary to study its influence on the mechanical properties of intermittent jointed rock mass.Based on the existing bond contact model,a novel bond contact model,in which the process of environmental degradation was simplified ultimately as the constantly dissolution of bond between the particles,was established and implemented into a commercial distinct element code.Then,a series of direct shear tests with different connectivity rates and normal stresses under various degree of environmental degradation was conducted in DEM.The results imply that there is a similar tendency of shear stress-displacement curves obtained from intermittent jointed rock mass samples with varying degree of environmental degradation.And with the increasing of environmental degradation degree,the main failure mode of intermittent jointed rock mass changes from tensile crack to shear crack.In addition,the initiation stress,the cohesion and internal friction angle of non-penetrating jointed rock mass are reduced with the increasing of environmental degradation degree.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2017年第9期2728-2736,共9页
Rock and Soil Mechanics
基金
国家重点基础研究发展规划(973)项目(No.2011CB013504
No.2014CB046901)
国家杰出青年科学基金(No.51025932)~~
关键词
环境劣化
非贯通节理岩体
直剪试验
离散元模拟
environmental degradation
intermittent jointed rock mass
direct shear test
DEM simulation
