Study On The Influence Of The Irregularity Of Fracture Structure On The Mechanical Properties Of Rock Mass

Rock in nature is a kind of non-continuous natural medium,and its discontinuity is mainly reflected in the large number of cracks and joints existing inside the rock.Due to the existence of internal joints of rock,the mechanical properties of rock mass are greatly different,and the natural cracks make the rock mass that has been affected more vulnerable.At present,scholars at home and abroad have explored the mechanical properties of jointed rock masses.However,there are few studies on the influence of cracks on the mechanical properties of jointed rock masses.Based on this,this paper takes the stress state of the joint direction of the jointed rock mass and the stress direction as the research object,and uses the similar material test to find the similarity of the rock mechanical properties under the stress state,and uses this mix ratio to cast prefabricated.The cracked specimens were mainly prefabricated by single cracks at different angles and cross-fracture cracks for physical experiments.The mechanical properties and failure modes of such rock mass under the influence of cracks are studied.Based on this experiment,the uniaxial compression specimens were numerically simulated using PFC particle discrete element software.The indoor physical experiments and numerical simulation results were compared and analyzed,and other types of cracks were discussed.The main contents of this paper are as follows:(1)The domestic and foreign literatures of jointed rock mass are reviewed to understand the relevant theoretical,physical experimental procedures and application status of numerical simulation software.Summarize the status quo and put forward the research route and test method of this paper.(2)Experimenting on the mechanical characteristics of jointed rock mass,using cement mortar and rubber powder as raw materials to make similar samples with the lowest tensile strength of jointed rock mass,and find the appropriate mix ratio of similar materials.The sample containing the single crack and cross double crack crack are prefabricated by the thin strip method,and the sample is subjected to uniaxial compression test.The loading process is monitored by Vic non-contact strain gauge,and the strength of the sample after the test is tested.Change and damage patterns are analyzed.(3)The physical uniaxial compression test was numerically simulated using PFC2 D 5.0 particle discrete element software.Try to explain the rock failure process with the concept of entropy and predict the damage of the rock.And use this numerical model to conduct further experiments on other structural cracks.