不同锯齿高度对软弱结构面剪切特性的影响

发布时间：2018-01-04 22:36

本文关键词：不同锯齿高度对软弱结构面剪切特性的影响　出处：《中南大学学报(自然科学版)》2017年05期 　论文类型：期刊论文

【摘要】：为分析不同法向应力与锯齿高度情况下软弱结构面的剪切行为,通过数值方法建立不同锯齿高度情况下的结构面计算模型,模拟在不同法向应力情况下的直剪试验,探讨结构面抗剪强度峰值前后的应力应变关系。建立剪胀角?与锯齿高度h之间的线性关系表达式。研究结果表明:随着锯齿高度增大,峰值抗剪强度对应的位移逐渐增大;应变软化阶段应力下降的速率呈先减小后增大的趋势,当锯齿高度与夹层厚度相同时达到最小值;峰值抗剪强度与残余抗剪强度均随锯齿高度的增大而呈线性增大,当锯齿高度达到一定值后,残余强度不发生变化;当锯齿高度较大如80 mm时,结构面法向应力与抗剪强度之间呈现显著的线性关系,而当锯齿高度较小时,两者之间的关系表现出一定的非线性特征,并且此时对应较小法向应力的剪切强度基本相同;随着法向应力增大,应变软化阶段应力下降的速率不断减小,残余强度与峰值强度的比值呈先增大后减小的趋势,最大值为0.961 4。
[Abstract]:In order to analyze the shear behavior of weak structural plane under different normal stress and sawtooth height, the computational model of structural plane under different sawtooth height was established by numerical method. The direct shear tests under different normal stress conditions are simulated to study the stress-strain relationship before and after the peak shear strength of the structural plane, and the shear expansion angle is established. The results show that the displacement corresponding to the peak shear strength increases with the increase of the sawtooth height. In the strain softening stage, the decreasing rate of the stress decreases first and then increases, and the sawtooth height reaches the minimum when the thickness of the interlayer is the same as the height of the sawtooth. The peak shear strength and residual shear strength increase linearly with the increase of sawtooth height. When the sawtooth height reaches a certain value, the residual strength does not change. When the sawtooth height is as large as 80mm, the relationship between normal stress and shear strength of the structural plane shows a significant linear relationship, but when the sawtooth height is small, the relationship between the two shows certain nonlinear characteristics. And the shear strength corresponding to the smaller normal stress is basically the same. With the increase of normal stress, the rate of stress decreasing in strain softening stage decreases continuously, and the ratio of residual strength to peak strength increases first and then decreases, the maximum value is 0.961 4.
【作者单位】：中南大学资源与安全工程学院;中国矿业大学深部岩土力学与地下工程国家重点实验室;
【基金】：国家自然科学基金资助项目(51474249,51374246) 中南大学“创新驱动计划”项目(2016CX019,2015CX005);中南大学研究生创新项目(2016zzts454) 深部岩土力学与地下工程国家重点实验室开放基金资助项目(SKLGDUEK1405)~~
【分类号】：TU452
【正文快照】： 岩体中节理力学性质是岩体稳定性的重要影响因素,国内外很多学者对节理岩体的力学性质进行了研究[1-3],特别是针对无填充的硬性结构面抗剪强度模型建立节理表面形貌经验模型JRC-JCS[4-5]。岩石结构面中常含有软弱介质夹层,人们对其进行了大量研究,如:葛修润[6]提出针对含软弱

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