不同裂隙数量砂岩体力学性状演变规律试验研究  

Experimental Study on Evolution Law of Mechanical Properties of Sandstone with Different Fracture Numbers

作　　者：王娟[1] 王星 袁超 吴禄源 WANG Juan;WANG Xing;YUAN Chao;WU Luyuan(College of Sciences,Xi′an University of Science and Technology,Xi′an 710699,China;Shaanxi Construction Engineering Eighth Construction Group Co.,Ltd,Xi′an 710001,China;School of Civil and Architectural Engineering,Henan University,Kaifeng 475001,China)

机构地区：[1]西安科技大学理学院,陕西西安710699 [2]陕西建工第八建设集团有限公司,陕西西安710001 [3]河南大学土木建筑学院,河南开封475001

出　　处：《河南科技大学学报（自然科学版）》2023年第5期56-64,M0005,M0006,共11页Journal of Henan University of Science And Technology:Natural Science

基　　金：国家自然科学基金项目(41772333);陕西省自然科学基金重点项目(2020JZ-53)。

摘　　要：对完整及裂隙砂岩样开展三轴压缩试验,结合扫描电镜、声发射定位、数值计算等表征手段,探明不同裂隙数量及围压条件下岩体力学性状及行为的演变规律,再现不同裂隙几何特征岩体破裂演化全过程,揭示细观角度下裂隙岩体破裂机理。结果表明:随围压的增大,裂隙岩体由脆性向延性转变,其强度增长速率逐渐减缓,2 MPa围压对岩体强度影响显著,完整岩样破坏形态由张拉向剪切转变,不同裂隙数量岩样均表现为剪切破坏;裂隙岩体变形破坏过程可分为裂纹萌生、裂纹稳定增长、峰前及峰后裂纹加速增长4个典型阶段;岩体裂纹扩展破坏形态由翼裂纹、次生共面裂纹和次生倾斜裂纹萌生及扩展3部分共同组成;预制裂隙上下端应力集中处裂纹首先萌生,翼裂纹沿拉应力释放区和压应力区边界扩展发育,剪切次生共面裂纹沿与裂隙倾角平行的方向汇合贯通,形成张拉-剪切复合型断裂面。Triaxial compression experiments were carried out on intact and fractured sandstone samples.Combined with scanning electron microscope,acoustic emission positioning,numerical calculation and other characterization methods,the evolution laws of mechanical properties and behaviors of rock mass under different fracture numbers and confining pressure conditions were explored.The whole process of fracture evolution of rock mass with different fracture geometric characteristics was reproduced,and the fracture mechanism of fractured rock mass under microscopic perspective was revealed.The results show that with the increase of confining pressure,the fractured rock mass transitions from brittleness to ductility,and its strength growth rate gradually slows down.The 2 MPa confining pressure has a significant effect on the rock mass strength.The failure mode of the intact rock sample transitions from tension to shear,and the rock samples with different fractures number show shear failure.The deformation and failure process of fractured rock mass can be divided into four typical stages of crack initiation,stable crack growth,pre-peak and post-peak crack growth stage.The crack propagation failure mode of rock mass consists of three parts of wing crack,secondary coplanar crack and secondary inclined crack initiation and propagation.The cracks at the stress concentration at the upper and lower ends of the prefabricated cracks first initiate,and the wing cracks expand and develop along the boundary of the tensile stress release zone and the compressive stress zone.The shear secondary coplanar cracks converge and connect in the direction parallel to the fracture dip angle,forming a tensile-shear composite fracture surface.

关 键 词：裂隙岩体 围压 力学特性 裂纹扩展 

分 类 号：TU452[建筑科学—岩土工程]