Study On Strength And Creeproperties Of Rocks With Ifferent Fractues In Different Angles

The natural fractured rock mass belongs to the formation of natural geological effect,and sampling is very difficult.Therefore,standard rock-like specimens made of cement and river sand similar materials are taken as the research object.Through uniaxial and triaxial destruction experiments,uniaxial and triaxial loading and unloading experiments,uniaxial and triaxial creep loading and unloading experiments,and freeze-thaw cycle experiments to study its physical parameters,strength,creep characteristics and failure modes,the freeze-thaw damage and frost heave mechanism were analyzed.Based on above all,the finite element ABAQUS software was used to simulate the creep of roadway.The feasibility of making rock-like specimens with similar materials is illustrated by similar three theorems.Using river sand,cement,and water as raw materials,fracture specimens were made from self-made cylindrical molds to prepare specimens of similar materials at different angles,which are prepared for subsequent trials.Uniaxial and triaxial cyclic loading tests were carried out on the fractured specimens,and the following test results were obtained.The uniaxial compressive strength increased significantly with the increase of the crack angle,and the elastic modulus gradually increased with the angle,Poisson's ratio.With the increase of the angle,it decreases;the friction angle and cohesion force increase significantly with the increase of the angle;the 90° fracture specimen has the smallest tensile strength and the complete specimen has the highest tensile strength.Through the uniaxial and triaxial cyclic loading and unloading tests on the fractured specimens,the following test results are obtained: The loading and unloading slopes of the specimens are not the same,and the unloading process has a high slope,regardless of whether the single axis loading or unloading or the three axis loading and unloading Under the circumstances,as the cyclic load increases,the area of the hysteresis loop gradually increases,and the energy dissipation gradually increases.The degree of damage to the specimen from the damage mechanics is also greater.The bulk modulus of rock determines the magnitude of frost-heaving force.The larger the bulk modulus,the greater the frost heave force within the pores during thefreezing phase.There is a non-linear positive correlation between rock bulk modulus and maximum frost heave force,and with the increase of modulus,the maximum frost heave tends to a certain value.The 0-degree fracture specimen is more likely to be damaged and destroyed,and the 90-degree fracture specimen ratio 0-degree fracture specimens are better able to withstand frost heave.Through uniaxial creep,triaxial creep,confining pressure unloading,and axial compression loading creep tests.The numerical analysis software ABAQUS was used to simulate the roadway with cracked and non-fractured roadway.Through the deformation cloud map and stress cloud map,it was found that the stress and deformation are obvious at the top area and floor of the roadway;Combined with engineering is the phenomenon of falling off at the top;Bottom drum phenomenon is easy to appear on the floor,which roadway excavation should focus on supporting places.If there is a crack project at the top during excavation,it is more important to deal with it when supporting.