摘要
钻孔剪切法是现场快速实测岩石抗剪强度的重要方法,但因测量误差较大导致其应用受限。通过对钻孔剪切原理及研究成果分析,发现了不完全剪切是岩石钻孔剪切试验误差大的原因,提出了基于压、剪不等面积的钻孔剪切法修正方法。设计实验装置开展钻孔剪切模拟试验,研究了不同剪切板参数下砂岩剪切力学参数表征规律,证明了所提方法的有效性和修正效果,最后通过文献数据验证了该方法的适用性。具体结果如下:①岩石钻孔剪切试验误差大的根本原因是受压面积和剪切面积选取失真且不相等,实际剪切破坏面积小于剪切齿齿间面积,且不同剪切齿长度情况下修正受压面积和剪切面积均随法向力的增大线性增大。基于剪切齿参数、受压面积和剪切面积的关系式,提出了钻孔剪切法修正方法。②岩石钻孔剪切的剪应力−剪切位移曲线可分为压密阶段、似弹性变形阶段、塑性变形阶段和峰后阶段。随法向力增大,不同剪切板参数下正应力、剪应力和剪切刚度均增大,达到剪应力峰值时的位移减小。钻孔剪切参数与剪切力学参数表征值之间存在明显规律。随剪切齿齿长的增加,黏聚力线性增大,内摩擦角呈二次函数增大。随剪切板面积的增加,黏聚力线性增大,内摩擦角呈二次函数减小。③剪切齿齿长和剪切板面积增大可在一定程度上减少测量偏差。剪切齿齿长从1.0 mm增大到2.5 mm,黏聚力和内摩擦角测量值的总偏差从62.96%降低到19.91%,总修正提升值从30.8%提高到74.1%;剪切板面积从400 mm^(2)增大到520 mm^(2),黏聚力和内摩擦角测量值的总偏差从64.07%降低到37.69%,总修正提升值从39.56%提高到56.05%。实验和文献数据验证均表明,本修正方法可以使钻孔剪切法测得的黏聚力和内摩擦角准确度分别提升约50%和6%。
The borehole shear test is an important method to quickly measure the shear strength of rock in the field,but its application is limited due to its large measurement error.By analyzing the principle of borehole shear and the research res-ults,it is found that incomplete shear is the reason for the large error of rock borehole shear test,and a correction method of borehole shear method based on the unequal area of pressure and shear was proposed.Experimental equipment was de-signed to carry out the simulated borehole shear test,and the characterization rules of sandstone shear mechanical paramet-ers under different shear plate parameters were studied,which proved the effectiveness and correction effect of the pro-posed method.Finally,the applicability of the method was verified by literature data.Specific results are as follows:①The root cause of large error in rock borehore shear test is that the selection of compression area and shear area is dis-torted and unequal,the actual shear failure area is less than the area between shear teeth,and the corrected compression area and shear area increase linearly with the increase of normal force under different shear tooth lengths.Based on the re-lationship between the parameters of shear tooth,compression area and shear area,a correction method of borehole shear test is proposed.②The shear stress-shear displacement curve of rock borehole shear can be divided into compaction stage,elastic deformation stage,plastic deformation stage and post-peak stage.With the increase of normal force,the pos-itive stress,shear stress and shear stiffness increase under different shear plate parameters,and the displacement decreases when the peak point of shear stress is reached.There are obvious rules between borehole shear parameters and the charac-teristic value of shear mechanical parameters.With the increase of the shear tooth length,the cohesion increases linearly,and the internal friction angle increases as a quadratic function.With the increase of the shear plate area,the cohesion in-creases linearly and the internal friction angle decreases as a quadratic function.③The increase of the shear tooth length and the shear plate area can reduce part of the measurement deviation.The shear tooth length increases from 1.0 mm to 2.5 mm,the total deviation of cohesion and internal friction angle decreases from 62.96%to 19.91%,the total improvement increases from 30.8%to 74.1%.The shear plate area increases from 400 mm^(2) to 520 mm^(2),the total deviation of cohesion and internal friction angle decreases from 64.07%to 37.69%,and the total improvement increases from 39.56%to 56.05%.Both experimental and literature data validation show that the correction method improves the accuracy of cohe-sion and internal friction angle by about 50%and 6%,respectively.
作者
张玉江
郝武帅
冯国瑞
崔炳渊
王千
王怡宁
朱德福
袁红辉
吴祥业
ZHANG Yujiang;HAO Wushuai;FENG Guorui;CUI Bingyuan;WANG Qian;WANG Yining;ZHU Defu;YUAN Honghui;WU Xiangye(College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Postdoctoral Research Station,Shandong Energy Group Co.,Ltd.,Jinan 250014,China;Deep Mining and Rock Burst Research Institute,Chinese Institute of Coal Science,Beijing 100013,China;Institute of Mining Engineering,Inner Mongolia University of Science and Technology,Baotou 014010,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2024年第5期2257-2269,共13页
Journal of China Coal Society
基金
国家自然科学基金资助项目(52374100)
国家杰出青年科学基金资助项目(51925402)
国家自然科学基金青年科学基金资助项目(52004172)。
关键词
原位测试
修正方法
钻孔剪切试验
剪切强度
力学参数
in-situ test
remediation method
borehole shear test
shear strength
mechanical parameters
