Study On The Mechanical Properties Of Single-fissure Rock Under Triaxial Compression

Fractured rock mass is a heterogeneous,discontinuous and anisotropic composite structure composed of different types of joints,cracks,weak interfaces and faults,which are produced by stress fields over a long period of time.Under normal circumstances,the mechanical properties of rock are relatively stable,but various defects are induced in the long-term natural evolution process.With the rapid development of rock engineering practice,the rapid improvement of social economy,petroleum exploration,underground pipelines,tunnels,etc.During the construction of rock engineering,the original rock will also be damaged to different degrees.The construction of a large number of underground engineering has caused the original cracks of the rock to aggravate and spread.In this complicated situation,the relevant theories of fracture mechanics and other related theories are used as the experimental guidance theory,and the indoor triaxial compression test is carried out on the rock sample containing a single fissure.The length of the fissure,the inclination of the fissure and the confining pressure are used as the test variables to explore the triaxial compression.The mechanical properties and failure laws of rocks with fissures under these conditions.The main research contents and results of this paper are as follows:(1)Introduced several basic theories related to fracture mechanics,such as:Griffith's energy balance theory,Orowan theory,Irwen fracture strength theory.(2)The uniaxial compression test and the triaxial compression test of the rock-like specimens are all completed by the HYAS-1000 C rock triaxial test system.At the same time,the uniaxial compression test is performed Use the camera to record the entire compression process of a rock sample with a single fissure;the angle of the fissure is0°,15°,30°,45°,60°,75°,90° and the length of the fissure is 5mm,10 mm,15mm,20 mm,25mm,etc.are combined into different types of rock samples containing prefabricated single fractures to perform uniaxial compression tests.The fracture angles are 0°,30°,45°,60°,90° and the fracture lengths are 5mm,10 mm,Triaxial compression test is performed on rock-like samples under the combination of 15 mm,20mm,and 25 mm.The record of test data is mainly based on Test.(3)Taking the length and inclination angle of the prefabricated cracks as the test variables,and taking the rock with single cracks as the test object,the law of stress-strain curve,peak strength and elastic modulus of the specimen under uniaxial compression are explored.And the crack propagation law of the specimen with cracks;the length and inclination of the prefabricated cracks are used as test variables,and the rock with single cracks is used as the test object,and the law of stress-strain curve,peak strength and The change law of elastic modulus,and the crack growth law of specimens with cracks.