不同粗糙度岩体节理面的应力松弛特性及机理  

Stress Relaxation Behavior and Mechanism of Rock Joint Planes with Different Roughness

作　　者：王振[1,2] 顾琳琳 沈明荣 WANG Zhen;GU Linlin;SHEN Mingrong(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact,The Army Engineering University of PLA,Nanjing 210007,China;School of Science NUST,Nanjing University of Science and Technology,Nanjing 210094,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094 [2]陆军工程大学爆炸冲击防灾减灾国家重点实验室,江苏南京210007 [3]南京理工大学理学院,江苏南京210094 [4]同济大学土木工程学院,上海200092

出　　处：《西南交通大学学报》2021年第2期253-260,共8页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金(42002266,51908288);岩土及地下工程教育部重点实验室开放研究基金项目(KLE-TJGE-B1903)

摘　　要：应力松弛是岩体节理面时效特性的重要组成部分,也是影响岩体工程长期稳定性的重要因素.为研究不同粗糙度岩体节理面的应力松弛特性,并进一步探索节理面的应力松弛机理,选取Barton标准剖面为人工模拟节理面的表面形态,并用水泥砂浆浇筑成型;然后,对其进行了分级加载剪切应力松弛试验,研究了不同粗糙度节理面在不同初始应力水平下的应力松弛曲线及应力松弛速率曲线特征,给出了松弛应力与初始应力之间的关系,并结合试验现象分析了应力松弛的发生机理.研究成果表明:随着初始松弛应力的升高,松弛应力先减小后增大,即岩体节理面应力松弛能力先减弱后增大,该现象与剪切过程中节理面的变形和裂隙发展有关,应力松弛是试验机为保持变形不变而不断调整,同时内部裂隙发育导致其内部抗力减小,进而引起应力下降的过程,并且粗糙度(JRC)越大,应力松弛能力越强.Stress relaxation is an important part of time-dependent behavior of rock joints,and also an important factor affecting the long-term stability of engineering rock masses.To study the stress relaxation characteristics of rock joints with different roughness and further explore the stress relaxation mechanism of rock joint planes,samples with artificial joint surfaces based on Barton’s standard profile lines were prepared by pouring cement mortar into shape.Then,shear stress relaxation tests with a multi-stage loading process were conducted to investigate characteristics of stress relaxation curves and stress relaxation rate curves for joint surfaces with different joint roughness coefficient(JRC)under different initial stress levels,the relationships between initial stress and relaxation stress were obtained,and the mechanism of stress relaxation was analyzed from the test phenomena.The results show that with the increase of the initial stress,the relaxation stress decreases first and then increases;that is,the stress relaxation ability of the rock joint planes decreases first and then increases.This phenomenon is related to the deformation and crack development of joint planes during the shear tests.The stress relaxation is a process in which the test machine constantly adjusts to keep the deformation unchanged and the development of internal cracks leads to the reduction of internal resistance, further resulting in the decrease ofshear stress;moreover,the stress relaxation ability of the rock joint planes increases with the increasing of JRC.

关 键 词：应力松弛 分级加载松弛试验 节理面 松弛机理 

分 类 号：TU448.27[建筑科学—岩土工程]