Research On Controlled Blasting Technology Of Rock Based On PFC

Blasting is a common method in rock excavation at present.To fully understand the structural characteristics of rock mass,to grasp the propagation law of blasting energy in rock mass,and to select suitable control blasting scheme,not only can achieve the expected blasting effect,but also improve the blasting efficiency and effectively ensure the safety and stability of the reserved rock.Therefore,it is of great significance to study the characteristics of engineering rock blasting and the study of co ntrolled blasting.The particle discrete element method is a relatively reasonable method to simulate the nonlinear material of rock mass.On the basis of the particle discrete element software PFC2 D,the simulation of rock blasting process and the simulat ion analysis of slope controlled blasting are carried out in this paper.This paper mainly studies from the following aspects.1.The basic principle of the particle flow theory is introduced in detail.With the help of the uniaxial compression test,the influence of the fine parameters of the particle on the macroscopic mechanical properties of the model is obtained,which provides a reference for the calibration of the meso parameters.2.Through laboratory rock mechanics test,the macro mechanical parameters of rock samples are obtained,which is the benchmark for calibration test.The establishment of the numerical model of the particle discrete element method is introduced into 4 parts,including the formation of the particle aggregation,the calibration of the model parameters,the application of the non reflective boundary and the setting of the damping parameters.3.A numerical model of rock mass is established by particle flow software PFC2 D.Blasting action is simulated by applying simplified blasting load on the hole wall.The monitoring results of the measured circle show that the explosion stress wave decreases gradually with the increase of the distance from the detonating point within the rock mass,and accor ds with the law of stress wave attenuation.Judging from the effect of blasting crater,PFC can better reproduce the whole process of blasting.The test result proves the rationality of PFC simulation blasting.4.Using the particle flow software PFC2 D,a model of unjointed and joint rock mass is established,and the simplified blasting load is applied to investigate the blasting damage characteristics of the unjointed rock mass.The area of the rock mass damage area is in agreement with the the ory.On this basis,the blasting damage characteristics of jointed rock mass are studied.The results show that the damage radius of rock mass increases with the increase of the angle between the joint and the axis of the blasting hole,and there is no obv ious law to follow the change of the depth of the damage zone,but the damage depth is the least when the angle of the joint and the axis of the hole is 90 degrees under the same condition.5.On the basis of analyzing the effect of blasting pa rameters on the effect of smooth blasting,combined with an engineering example,the control problem of the damage zone in the cutting slope of the cut slope in the new expressway is simulated and analyzed,and the corresponding control blasting scheme is established.