Study On Dynamic Response And Safety Protection Of Concrete Gravity Dam Under Explosive Impact Load

China’s water conservancy industry has developed rapidly in the past decades.In the process of river management in various regions,large-scale construction of hydropower stations,time-conditioning of water resources,and optimization of water resources allocation in arid and water-scarce areas,China has built a large number of hydraulic structures,which has brought huge social benefits and economic construction returns.Concrete gravity dam is a common hydraulic structure.Because modern warfare uses precision missile strikes as the main method,the dam,as the main facility of national economic construction,the important pillar of people ’s livelihood security and national social stability,will certainly be one of the first targets of war.Secondly,with the largescale development of underwater engineering,underwater blasting construction will be also more and more widely used.Therefore,it is very important to study the response of gravity dam and related safety protection under the shock of an explosion.This paper is devoted to study the dynamic response of concrete gravity dam after being subjected to explosion shock loading and the effect of bubble curtain on explosion shock wave reduction.The main work is as follows:(1)The research of the dynamic response of concrete gravity dam after being subjected to explosion shock loading.According to the strain rate effect of concrete and fluid-solid coupling algorithm,building a three-dimensional fluid-solid coupled model which includes water,air,explosives,dam body,dam foundation multiple factors.Rely on LS-DYNA display dynamic analysis program,a numerical simulation is conducted on effect of explosion shock wave with different shock wave propagation media,different explosion depths,different explosion distance on concrete gravity dam.The form of destruction and responses of concrete gravity dams after shock waves generated by explosions from different locations are analyzed.(2)Reduce the explosion impact load on the gravity dam to achieve dam safety protection.According to the theory one-dimensional stress waves which are transmitted and reflected at the interface of different media,analyzing the reduction effect of air bubbles on underwater explosion shock waves,building a bubble curtain coupling model with air-water combination.Studying the reduction effect of the bubble curtain on the explosion shock wave,we should consider the interaction between the underwater explosion shock wave and the bubble curtain.At the same time,analyzing the effects of single-layer curtains,multi-layer curtains and different positions of curtains on underwater shock waves.Through numerical simulation calculating and result analyzing,the following conclusions are drawn: When an explosion may occur in air or water,we should pay more attention to the harm caused by the explosion in water.Detonation depth and detonation distance have a great influence on the damage degree of concrete gravity dam.In order to better protect the gravity dam,we should focus on protecting the dam head and stress concentration.Bubble curtain can effectively reduce the intensity of underwater explosion shock wave.The protective effect of setting the bubble curtain near the gravity dam is better than that near the medicine bag.The number of layers of bubble curtain can significantly affect the reduction effect of shock wave.