| Sluice is a kind of low head hydraulic structure in hydraulic engineering.It is mainly used in water resources regulation,agricultural irrigation,water level regulation,flood control and water storage.According to incomplete statistics,the total number of sluice gates built in China exceeds 60000,which are widely distributed and involve complex geological conditions.In coastal areas,soft soil foundation is often used as the foundation of sluice,but this kind of soil has obvious disadvantages,such as slow drainage and consolidation of soil and high compressibility of soil.In natural state,soft soil foundation is usually difficult to meet the requirements of foundation settlement and bearing capacity in the code,so it is often necessary to strengthen the soft soil foundation.When the sluice is subjected to an earthquake,it may cause damage to the sluice,resulting in its failure to operate normally.In serious cases,it will also produce structural damage,resulting in chain effects such as secondary floods.The influence of earthquake on sluice structure can be reflected in the following three aspects:(1)the static and dynamic water pressure of water body caused by earthquake,especially the dynamic water pressure has a great impact on the structure;(2)The stiffness of sluice varies greatly in all directions and the load distribution is uneven;(3)Many sluice gates are built on soft soil foundation.Under the action of earthquake,it is easy to cause shear failure of soil and flow soil.Therefore,it is very important to analyze the structural stress of sluice on soft soil foundation from static and dynamic aspects.In the static and dynamic analysis of sluice,the plasticity of soil and the nonlinear relationship of pilesoil contact need to be considered.In the case of ground motion,the seismic response of soil and sluice structure is very complex,and the analysis is very difficult.In this paper,the proposed sluice on soft soil foundation is taken as an analysis example,the 5#sluice chamber of the sluice is selected as the analysis object of this paper,the sluice foundation model is established by using three-dimensional finite element analysis software,and the static and dynamic analysis of the model is carried out.This paper mainly carries out the following research:(1)Starting from the coupling theory,this paper mainly introduces the basic principle of fluid structure coupling and the analysis theory of pile-soil coupling;Three main dynamic research methods are comprehensively analyzed and their advantages and disadvantages are compared;The viscoelastic boundary theory is expounded.(2)In the static analysis,ABAQUS software is used to establish the corresponding calculation model,the pile-soil-superstructure coupling system is established,and the pile-soil-floor contact is considered.The displacement and stress of the sluice structure are analyzed from the three working conditions of completion period,check water level period and irrigation water retaining period,the stress and settlement of each part of the structure are obtained,and the relevant data are analyzed.The results show that during the check flood period,the settlement of foundation soil is the largest,and the settlement value is 8.60cm,which meets the requirements of sluice design code;By calculating the stress value of each structure of the sluice under different working conditions,it provides a certain reference for the design and reinforcement of the proposed sluice.(3)The fluid structure coupling effect is considered,the acoustic unit is used to simulate the water body,and the natural vibration analysis of sluice chamber structure is carried out in the completion period,check flood period and irrigation water retaining period.The results show that the structural internal water body can reduce the natural vibration frequency of the sluice,and the presence or absence of the gate will also have a certain impact on the natural vibration frequency of the sluice.(4)The seismic wave input is verified,the acceleration in three directions is applied,and the acceleration input from the bottom is compared with the acceleration output from the top.The results show that the coincidence between the verification results and the theoretical results is high,and the seismic wave input program is reliable.(5)Seismic effects and fluid structure coupling effects are considered,the reasonable seismic wave is selected,the three-dimensional seismic wave is applied to the model,and the completion period of sluice and irrigation water retaining period are used for dynamic response analysis respectively.The characteristic points selected in the sluice structure are selected,the relative displacement time history curve is analyzed,and the maximum principal pressure and tensile stress of the sluice structure are analyzed.From the analysis of displacement time history results,the relative displacement response of characteristic points intensifies with the increase of height.From the analysis of structural stress results,as for the sluice as a whole,the maximum principal pressure and tensile stress response under irrigation water retaining period are greater than that in the completion period.Under the action of earthquake,the maximum principal pressure and tensile stress of the sluice increase to varying degrees compared with the static working condition.The stress increase value of the bent structure,the gate,the gate slot and the cement pile near the toothed wall is relatively large,which needs to be paid more attention in the engineering design. |
