单台多尺寸岩石压剪断裂试验装置的研制与应用研究  

Development and application research of a compression shear fracture test device for multi-size rock

作　　者：吕原君 杜时贵 罗战友 冯慧坤 李浩[1] LYU Yuanjun;DU Shigui;LUO Zhanyou;FENG Huikun;LI Hao(Institute of Rock Mechanics,Ningbo University,Ningbo,Zhejiang 315211,China)

机构地区：[1]宁波大学岩石力学研究所,浙江宁波315211

出　　处：《岩石力学与工程学报》2022年第10期2067-2081,共15页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41427802,42177117);浙江省万人计划领军人才(2020R52028)。

摘　　要：为测试多尺寸岩石在压剪复合应力条件下裂纹起裂扩展及断裂面滑移过程的力学性能,针对现有相关试验装置所测试样尺寸较小且规格单一、最大试验力不高等实际情况,研制了一种在双轴可同步或依次施加压缩荷载和剪切荷载的多尺寸岩石压剪断裂试验装置。主要由主机框架、加载测力机构、试样盒、试样就位机构、电液伺服控制系统、操作软件等组成,可实现尺寸范围为50~300 mm的正方体试样、同宽度长方体试样和等比例长方体试样的试验,其中法向最大荷载为1500 kN,切向最大荷载为3000 kN。分析了由主机框架和加载测力机构组成的试验装置刚度,探讨从岩石断裂前的荷载控制向断裂面滑移过程的位移控制转换条件。标定试验装置的荷载精度,结果表明在荷载测试范围2%~100%的示值精度达到0.5%。在压缩荷载和剪切荷载依次加载条件下,开展了对长宽比为2∶1的等比例长方体多尺寸花岗岩试样的初步应用,结果表明:首先,对花岗岩试样分别施加法向最小荷载和大荷载,从剪切荷载随时间及位移的关系曲线中反映了该装置的测试精度和稳定性;其次,2个切向测力传感器分别安装在试样盒左侧的加载端和右侧的支撑端并获得测试结果,通过对比发现在岩石裂纹起裂扩展瞬间所测数值存在不同步现象;再次,当相同尺寸的试样分别施加不同法向压缩荷载时,获得的剪断荷载峰值随压缩荷载的增加而不断增加;最后,对3种连续小尺寸试样分别施加10和20 MPa的法向压缩应力时,剪断峰值应力随试样尺寸的增加存在非线性关系。It is necessary to test the mechanical properties of crack initiation,crack propagation and slip process of fracture surface for multi-size rock under compression shear composite stress.A multi-dimensional rock compression shear fracture test device has been developed,which can apply compression load and shear load synchronously or successively on biaxial.In comparison,some deficiencies exist in existing related equipment,such as the sample size that can be tested is small and single specification,the maximum test force is not high,etc.The developed device is mainly composed of frame,loading and force measuring mechanism,sample box,sample positioning mechanism,electro-hydraulic servo control system,operation software,etc.Cube sample,cuboid sample with the same width or equal ratio can be tested in the size range of 50-300 mm.The maximum normal load is 1500 kN and the maximum tangential load is 3000 kN.The stiffness of the test loading system composed of frame and loading mechanism was analyzed.The transition condition from the load control before rock fracture to the displacement control during the slip process of the fracture surface was discussed.The load accuracy calibration of the test device has been carried out.The results show that the indication accuracy reaches 0.5%in the load test range of 2%-100%.A preliminary experimental study on the multi-size cuboid granites,with an aspect ratio of 2∶1,have been carried out.The results are as follows:Firstly,the minimum and large normal load were applied separately to granite samples.Test accuracy and stable loading have been showed by obtained relationship curves of shear load with time or displacement.Then,the test values of two tangential load cell,located at the loading end and support end of the sample box,were obtained.During the initiation and propagation of rock cracks,it is found that the measured values were not synchronized through comparative study.Then,the peak shear load increased with the increase of normal load when different normal loads were app

关 键 词：岩石力学 多尺寸 压剪断裂 试验装置 

分 类 号：TU45[建筑科学—岩土工程]