Numerical Simulation Study Of Blasting Vibration On The Rupture Of Concrete Spray Layer In Rock Tunnels

In the coal mine tunnel excavation, a large number of roadway are used to spray concrete for supporting, the influence of blasting vibration on existed concrete spray layer or surrounding rock mass of the roadway under excavating is inevitable if the method of blasting is employed for excavation. Therefore, Studying of the influence of blasting to the concrete spray layer under strong impact load takes on very important theoretical significance and engineering realistic values.In the paper, the concrete specimen, the concrete spray layer and the blast resistance of concrete were by the two methods of theoretical analysis and numerical simulation. Specifically, the main achievement of this research is as follows:1. The transmitting regularity of the stress wave in the rock and the interface were analyzed in the theory. Divided into different regions according to the different distance to the explosion center, the formula is derived from the theory. Based on the viscous-elastic-plastic constitutive equations of P.Perzyna, and considered the concrete of the damage evolution following Weibull distribution, the viscous elastic plastic dynamical constitutive model of soft rocks with damage.2. Based on ANSYS/LS DYNA3D numerical simulation software to simulate the SHPB experiment for concrete specimens, results show that it has certain impact on dynamic properties when the impact velocity and the static compressive strength of concrete specimen are different.3. The numerical simulation on the research of explosives blasting inside the concrete was discussed. It was studied on the formation of internal crack and the development. Blocks of concrete internal stress, velocity and kinetic energy, internal energy is analyzed, and verified the result of the part. It is analyzed to the concrete blocks of internal stress, velocity, kinetic energy and internal energy, and verified the results of the part.4. During the blasting excavation of the rock tunnel influence of concrete spray layer with different age and the different static compressive strength of concrete are analyzed by using the large-scale finite-element method software of ANSYS/LS-DYNA. The degradation of stress wave along the concrete spray layer is obtained. The method has taken for solving the rupture of concrete spray layer in the process of excavating for rock tunnel of the coal mine.