Centrifugal And Numerical Modedling On Dynamic Responses Of Gravity Dam Subjected To Underwater Explosion

With the renovation and construction of navigation channels and ports in China gradually developing from shallow sea to deep sea,major water conservancy projects have created significant political and economic benefits,and DAMS are common important national infrastructure,shoulding power generation,flood control,flood control and other important missions,so the safety and protection of DAMS is worth discussing.Because of the importance of the dam,it is easy to become the target of war and terrorist attacks.In modern times,the scale and amount of explosive explosive used in underwater blasting are gradually increasing.The impact of underwater blasting on ships,wharves,DAMS and other hydraulic structures has become an urgent problem to be solved.The influencing factors of underwater explosive power are relatively complex,including water depth,explosive equivalent,explosive shape,near and far field and bubble pulsation.Therefore,it is very important and urgent to study the dynamic response and preventive measures of hydraulic structures caused by underwater explosion.In this paper,ABAQUS is used as the calculation tool and numerical simulation method is adopted in combination with centrifuge test to study the influence of changes in water level and impact factor on the dynamic response of dam body and damage effect.The main research work and results are as follows:1)centrifuge test study of the dam,this paper designed a set of centrifuge test,by turning the centrifuge to achieve scale effect,and strain gauge on the dam body,velocity and acceleration sensors to get the dynamic response of the dam body response data,analyzed the dam dynamic response under typical working conditions,and the influence of storage level changes on dam responses;Then it provides a data base to verify the reliability of the numerical simulation model.Moreover,the calculation basis of concrete structure in underwater explosion calculation is clarified,in which the three-dimensional full-coupling model considering the effect of concrete strain rate is established.In addition,fluid medium is simulated by acoustic element and fluid-solid coupling simulation method is used to realize fluid-solid coupling.This part also discusses the setting of the boundary and presents the working condition for studying the influence of the water level.2)Based on THE FINITE element software ABAQUS,the similarity between the prototype results and the centrifuge results is verified,and the water area grid is modeled and compared;Secondly,the numerical simulation results are compared with the experimental results to obtain the validity of the numerical simulation model.In addition,the numerical calculation results and the experimental results are used to analyze the location where the dam body is prone to failure under the action of underwater explosion load and the influence of the change of water level on the dynamic response of the dam body.The results show that under the action of underwater explosion,the peak value of vertical tensile stress is easy to occur in the position of variable section of the dam body,the bottom of the dam body and the middle and lower part of the dam body,which leads to horizontal cracks and damages of the dam body.With the increase of the water level,the dynamic response of the dam will increase,and the degree of damage will deepen.With the increase of the water level,the wet surface area of the dam will increase,the received shock wave energy will increase,and the kinetic energy and strain energy generated by the dam will also increase significantly.3)In order to evaluate the impact of different impact factors on the dynamic response and damage effect of the dam.Considering the boundary influence,the spherical wave impact factor is modified,and the method similar to that in chapter 3 is used to build a three-dimensional full-coupling model with no boundary reflection.Under this model,factors such as explosion distance,water depth and water entry depth,etc.are explored to compare the dynamic response and damage degree of the dam body under different working conditions under the same impact factor.It is found that when the impact factor is unchanged,the damage degree of the dam body facing the blasting core is basically unchanged,and the dynamic response of most working conditions is basically unchanged.Then the impact factor was changed to calculate,and the results were compared.It was found that the impact factor was linearly correlated with the degree of damage and the dynamic response of the dam,which provided relevant Suggestions for the protection of the dam.