Study On The Influence Of The Spatial Distribution Of Deep Underground Caverns On The Propagation Of Explosive Seismic Waves

With the improvement of people’s living standard,the demand for electricity is more and more intense,and the construction of hydropower station is more and more.Underground cavern group is widely used in hydropower station system.In the construction of underground caverns in blasting excavation,economic and efficient,but the adverse effects of blasting vibration effects caused by the caverns of the safety and durability of the blasting excavation of caverns has become one of the difficulties in engineering,blasting seismic wave propagation has been affected by the engineering concern.Taking Xiluodu Hydropower Station underground chamber excavation of diversion tunnel as the background,in several field blasting vibration test on the basis of study on the excavation of diversion tunnel at right bank near the explosion vibration caverns response method combining numerical simulation by using regression analysis and dynamic finite element.The main contents are as follows:(1)The numerical computation model based on Xiluodu is established.Based on the experimental data of the field blasting vibration test,the numerical simulation model is established and the response law of the underground cavern group blasting is systematically studied.Through the monitoring of the vibration speed,the attenuation law of blasting vibration is analyzed,and the basis for numerical simulation and vibration monitoring is provided,and the feasibility of numerical simulation analysis is verified by field construction and monitoring.(2)Summarizes the deep caverns of explosion seismic wave vibration response characteristics.The blasting response characteristics of the middle and deep caverns are analyzed by comparing the vibration time curve,the peak value of the vibration velocity and the velocity attenuation rate of the mass,and by comparing the three conditions of no stress,medium ground stress and high ground stress.Based on the following two aspects: the action of dynamic load and the interaction between dynamic and static loads,the response rules of velocity,stress and displacement of cavern group under the action of blasting seismic wave are comparatively analyzed.Compared with the shallow part,the dynamic response of the caverns in the middle and deep parts mainly has the following characteristics: the peak of the velocity of vibration increases relatively in the vault and the bottom plate,the vibration speed curve attenuates faster,the displacement response is relatively increasing,and the stress response decreases relatively.(3)The best spatial distribution of three diversion caverns was determined.According to the three working conditions of vertical,lateral and span in different space positions of the cavern,the vibration response of the caverns in each chamber of the caverns is analyzed,and the position of the peak vibration velocity in each condition is analyzed.The following rules are obtained: the parallel arrangement of the blasting vibration in the cavern is the least,and the vibration of the cavity is more than 3 times the span of the cavity.The velocity of the half wall of the straight wall increases with the increase of span,while the vibration velocity decreases with the increase of span.On the basis of the law,the suggestion of the safety monitoring control point is given to better control the influence of the excavation of the caverns on the adjacent caverns,and to provide reference for the space design of the caverns.