摘要
在充分考虑裂纹尖端应力场Williams展开式中非奇异应力项对裂纹扩展影响的基础上,提出了考虑裂纹表面摩擦效应和T应力影响的裂纹尖端附近应力的理论解,并利用修正的最大周向应力准则分析了压缩荷载作用下T应力对裂纹起裂、扩展行为的影响;通过单轴压缩试验裂纹起裂角的试验结果与理论值的对比,验证了考虑3个T应力分量(T x、T y、T xy)所得理论解的合理性。结果表明:初始裂纹倾角β一定时,裂纹尖端最大周向应力σθmax和剪切应力绝对值的最大值|τrθ|max随着裂纹表面摩擦系数f的增大逐渐减小;σθmax和|τrθ|max随着侧压力系数k的增大呈先减小后增大的趋势;k和β越大,裂纹发生剪切开裂的概率越大;通过调整T应力的大小,可以有效控制裂纹扩展的方向,使其偏离危险方向,有效延缓或阻止构件发生整体断裂。
Based on the influence of nonsingular term in Williams expansion of the stress field at a crack tip on crack propagation,a theoretical solution of stress was proposed with considering the friction effect of crack surface and T-stresses.The modified maximum tangential stress criterion was used to analyze the effect of T-stresses on crack initiation and propagation under compression loading conditions.Through the comparison of the test results and the theoretical solutions under uniaxial compression conditions,the rationality of the theoretical solution was verified by considering the three T-stress components(T x,T y and T xy).The results show that for a certain crack inclination angleβ,both the maximum tangential stressσθmax and the maximum absolute value of the shear stress|τrθ|max at the crack tip decrease gradually with the increase of the friction coefficient f of the crack surface.Bothσθmax and|τrθ|max decrease first and then increase with the increase of the lateral pressure coefficient k.The possibility of shear crack is higher with larger k andβ.The results also reveal that the T-stresses can be controlled to keep the crack growth direction away from the dangerous direction and the overall structure fracture can be effectively stopped or delayed.
作者
李金凤
何兆益
李修磊
杨超
LI Jinfeng;HE Zhaoyi;LI Xiulei;YANG Chao(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;College of Traffic and Transportation,Chongqing Jiaotong University,Chongqing 400074,China;Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang 443002,China)
出处
《水利水电科技进展》
CSCD
北大核心
2019年第6期44-50,共7页
Advances in Science and Technology of Water Resources
基金
中国博士后科学基金(2018M633627XB)
国家自然科学基金青年科学基金(41807276,41602301)
关键词
岩石力学
压缩荷载
T应力
应力强度因子
起裂角
rock mechanics
compression load
T-stresses
stress intensity factor
crack initiation angle
