Study On Mechanical Properties And Failure Law Of Single Fractured Rock-like Material Under Uniaxial Compression

Rock is a complex natural medium,all kinds of defects such as cracks,holes and so on occurred inside when it is under various loads during a long geological age,however,the defects are an inducement to trigger the engineering accidents like rock burst and collapse of surrounding rock.At present,many scholars home and abroad carried out a number of researches to investigate the fractured rock,acquiring many conclusions that are playing an important role in conducting design and construction.But there are many shortages in the field of mechanical characteristics and failure law of fractured rock,such as the influence of fissure length and the manufacture method of standard specimen on fractured rock.On the base of the research status and related theories of fracture mechanics,an experiment research is carried out to investigate the mechanical characteristics and failure law of fractured rock-like material with one fissure under uniaxial compression,establishing a damage constitutive model when the fissure length and fissure angle are taken into account.A finite difference software FLAC3 D is adopted to simulate the uniaxial compression experiment,and contrast the simulation and experimental results.The main contents are as follows:(1)Collecting and consulting related literature on fractured rock mass at home and abroad,to understand the research status of related theories,laboratory tests and numerical simulation of mechanical properties and failure laws of fractured rock mass.and then to sum up the shortcomings of the current research and puts forward the research contents and technology roadmap.(2)Introducing the classification of rock fracture from different aspects,then summarize the related theories of fractured rock mass from the aspect of rock fracture mechanics.(3)A steel die for making standard fractured specimen is prepared,high strength silica fume mortar material is adopted to make rock-like material specimen.And a pull-out steel sheets method is adopted to design fissure inside the rock-like material.The Grubbs method is applied to analysis the results of uniaxial compression experiment.The influence of fissure with specific angle and length on mechanical characteristics and failure law of rock-like material is analyzed.(4)Based on the damage mechanics theory and strain equivalence principle,a damage constitutive model for fractured rock mass considering crack dip and fissure length is established.Then using the Flac3 D finite difference procedure to simulate the uniaxial compression test based on the custom damage constitutive model,to verify mutually with the laboratory tests.