Study On The Influence Of Blasting Vibration On Supporting Structure Of Surrounding Rock

The drilling and blasting method is still the main rock breaking method in the tunnel excavation. In order to ensure the stability of the roadway, the support of the surrounding rock must be supported. Blasting stress wave and blasting vibration effect will have adverse effects on the concrete spray layer. Therefore, study on blasting dynamic load under the action of shotcrete layer, dynamic mechanical properties is of important theoretical significance and practical significance.Supported by the National Natural Science Foundation of China "Basic research on rock crushing mechanism and application of deep hole advanced fracture blasting in infinity rock mass(No:51404010)". Based on the damage model of concrete and blasting vibration theory,in theory to establish jet concrete damage model, using ANSYS/LS-DYNA finite element method, stress variation and the resulting spray layer damage mechanism analysis of blasting vibration in tunnel excavation of the shotcrete.According to the theory of stress wave, the propagation law of shock wave, stress wave and seismic wave in medium are analyzed, and the propagation and attenuation of stress wave in concrete are analyzed emphatically. The reflection and transmission of the stress wave in the concrete and the rock surface is studied. The damage constitutive model of concrete under impact load is compared and analyzed, and the model is used as the model.Finite element analysis of concrete for 1 days of age shows that the closer the distance from blasting source, the greater the vibration velocity of concrete spray layer, the easier the concrete damage. Through the different age concrete spray layer under the action of blasting in deformation analysis, we found that, different age concrete spray layer stress wave under the action of damage degree and the extent of damage different age more concrete spray layer under the action of stress wave deformation degree is small, range and damage by the smaller. The results of the monitoring and analysis of blasting vibration are similar to the results of simulation.