Research And Application Of Gathering Water Pressure Smooth Surface Blasting Of Long And Large Mountain Tunnel

In recent years,with the support and guidance of the national government,various regions are vigorously advancing road infrastructure construction,and tunnels are one of the indispensable ways for mountain road infrastructure.However,traditional smooth blasting has large surrounding rock disturbances and is prone to over-excavation.Problems such as high dust concentration have delayed the construction process of the tunnel,which is time consuming and laborious.The concentrated water pressure smooth blasting technology is easy to operate,has small disturbance of surrounding rocks,high half-hole mark rate,high economic efficiency,and low dust concentration.Characteristics,but due to improper construction operations on the site,blasthole charges are easy to leak with water bags or gun mud,which causes a series of problems in construction.In order to further determine the role of the energy pool,water bag and gun mud,the water surface of the energy pool has been blasted.Further development of technology.Relying on the newly constructed Guantian tunnel project in the ZJHZQ-9 bidding section of the Zhangjiajie-Jishou-Huaihua railway project,this paper uses the theoretical analysis,numerical simulation,and field test research methods to study the law of stress propagation in rock blasting under different charge structures in the blasthole.By comparing and analyzing the vibration and displacement changes of the seismic waves generated by the charged blasting of different charging structures,the following conclusions are obtained:(1)Based on the basic theory of rock blasting,the principle of energy accumulation and the formation mechanism of energy jets are introduced,and the energy loss mechanism of energy blasting is analyzed from the perspective of energy jet penetration.By introducing the principle of water pressure,the impact of blasting shock waves in water The decay law of time and the effect of water medium on rock breaking during the blasting process are analyzed;the blocking effect of gun mud and the movement law of gun mud in the blast hole are analyzed.(2)Numerical simulation was performed using ANSYS/LS-DYNA software.The rock material used JHC constitutive and high-energy explosives carried by LS-DYNA for numerical simulation,which respectively simulated the concentrated water pressure smooth surface blasting and the waterless bag-gathering energy.The blasting stress and the blast-free mud-energy-gathering blasting were used to compare and analyze the blasting stress propagation law and surrounding rock damage of the three charging structures.The results show that the blasting stress propagation of the concentrated water pressure smooth surface is outstanding,and there is obvious stress concentration at the water bag,followed by non-blasting mud-gathering blasting,and finally the waterless bag-gathering blasting,which reflects the water wedge.At the same time,the rocks around the blasting blastholes of the three charge structures were damaged in the shape of blades(longitudinal,short and horizontal),which verified the action of the energy-concentrating jet of the energy-concentrating tank.(3)Use ANSYS/LS-DYNA software to carry out numerical simulation,and compare and analyze the changes of vibration speed and displacement of the three charging structure blasting simulations.The results show that the waterless bag-gathering blasting has the largest vibration velocity,followed by the gunless mud-gathering blasting,and the energy-gathering water pressure smooth blasting has the smallest vibration velocity,indicating that the water medium has a certain energy storage and buffering effect.The displacement change is the opposite.Under the combined action of water bag and gun mud,the water wedge action expands the cracks in the surrounding rock,making the displacement change of the energy-condensing smooth surface blasting the largest.Among them,the three charging structures The displacements are larger than those in the non-focusing direction.In order to reduce disturbance to the surrounding rocks and improve the utilization rate of explosives,water bags and artillery mud must be loaded in strict accordance with the requirements.(4)Through field tests and engineering applications,the rock-breaking effects of concentrated charge blasting with different charge structures were studied,and the accuracy of the simulation was verified based on the rock crack orientation,crack width,and engineering application after the test blasting.The results show that the maximum value of rock fissures is obtained in the direction of the energy-concentrating groove when the energy-condensing water-pressure smooth surface blasts.The width corresponds to the simulation results,verifying the accuracy of the simulation.