Mechanism Of The Influence Of Blasting On The Surrounding Rock Of Deep Zoning

A series of new scientific phenomena occurred in the deformation and destruction of surrounding rock when excavating a cavern or roadway in a deep rock mass.There were alternating ruptured zones and non-ruptured zones in the surrounding rock of the cavern.Blasting is still the main method for excavation of deep rock mass,and it is inevitable to impact on the cracking of surrounding rock in some deep areas.There are important theoretical and practical engineering significance to study the disturbance mechanism of blasting load on partitioned cracked surrounding rocks for the safety and stability of deep rock mass.The paper explores the issue of blasting disturbances to the surrounding rock in deep subsidence areas through theoretical calculations and numerical simulations.The paper explores the issue of blasting disturbances to the surrounding rock in deep subsidence areas through theoretical calculations and numerical simulations,and it is verified by model test.The results obtained as follows:(1)In this paper,the analytical model of the stress wave passing through the single-layer and double-layer joint surfaces is established,and the energy law of the stress wave reflected and transmitted through the joint surface is obtained.(2)It is concluded that the generation of tensile stress in the rock rod is caused by the superposition of reflections from the fixed end to the unloading wave by analyzing the propagation process of the unloading wave in the rock rod.The pull strain is larger near the fixed end and smaller near the free end.Jointed rock rods loosen at joints after unloading is completed,and the rods are broken at high strain rates.According to the formation mechanism of partitioned surrounding rocks,when the initial stress is further increased,the gaps in the existing joints of the rock joints will increase,which will further hinder the propagation of stress waves,and new stress fractures will occur after the unloading.(3)Through numerical simulation analysis,the results obtained that the existence of joints in fractured surrounding rock will increase the vibration velocity and tensilestress of blasting surrounding tunnels in blasting unloading.(4)Through the model test,the stress wave has multiple reflections and transmissions on the joint surface and the free surface.When the free surface reflects,the wave properties change,and at the joint surface,it overlaps with waves of different properties,resulting in stress superposition.