Numercial Simulation Of Marble’s Failure Process By PFC2C And Its Experiment Proving Under Loading And Unloading Conditions

With the increase of mine excavation and underground project, the research on therock in the process of excavation unloading is growing. But this development is limitedby the indoor experiment. In order to study the mechanical properties and its changes ofrocks in the process of excavation, the numerical simulation can be adopted.This paper takes the Henan’s marble as object of study. On the basis of differentloading and unloading mechanical failure test of the marble, it explores how to use thenumerical simulation software PFC2D which bases on the discrete element to simulatethe marble under different loading and unloading conditions of the force anddeformation’s failure mechanism. The simulation results has proved its feasibility tosome degree, and obtained the verification of the indoor experiment..The main researches of this paper are as follows：(1) Based on the marble’s destructive test which is under different loading andunloading conditions, it explores the feasibility of the rock’s failure mechanism underthe complexing loading and unloading conditions by using the numerical simulationsoftware PFC2D. It basically builts the numerical model of the conventional tri-axialtest and the pre-peak unloading experiment. And combined with the indoorexperimental results, it systematically studies the influences of the mesomechanicsparameter on the macromechanics (elasticity modulus, poisson’s rate, mode of failureetc.) when the PFC2D is systematically researched with numerical simulation. And thesimulation parameters are determined reasonably.(2) The numerical simulation of marble’s failure process under conventionaltri-axial test is carrried and the numerical simulation results are basically consistent withthe actual experimental results, such as cohesion and internal friction angle. Althoughthe stress-strain curve is not exactly the same, the error is in the allowable range, andthe mesoscopic parameters based on unloading research are obtained.(3) It focuses on the research on numerical simulation of the failure mechanismand mechanical parameters of marble pre-peak under the conditions of differentconfining pressures and different unloading rates. Through the analysis of the changing rules of the stress-strain curve, failure forms and the shear strength derive fromnumerical simulation, rock failure mechanism based on the above unloading conditionis concluded.