Static And Dynamic Analysis Of Sluice Structure Considering Pile-soil Contact And Fluid Structure Coupling

As a kind of low head hydraulic structure,sluice is widely used in water resources regulation,water level regulation,water storage irrigation and so on.The sluice constructed in our country has a wide range of distribution.In the case of earthquake disaster,it may cause damage to the structure and affect its normal operation.In serious cases,it will cause structural damage and secondary flood and other chain reactions.The anti-seismic performance of sluice structure is mainly reflected in the following three aspects: first,the existence of water body will produce static water pressure and dynamic water pressure under the earthquake action,especially the dynamic water pressure will have a greater impact on the structure under the earthquake action.Secondly,the stiffness of sluice varies greatly in all directions.Thirdly,many sluices are built on the soft soil foundation.The obvious nonlinear characteristics of the soft soil foundation under the action of earthquake make the coupling analysis between the sluice and the foundation very complex,and the dynamic analysis and calculation is very difficult,which needs to be further studied.In this paper,taking the practical engineering of Yucao sluice as an example,taking the4#sluice chamber as the research object,considering the dynamic interaction between water body,structure and foundation and the nonlinear problem of pile-soil contact,a three-dimensional finite element simulation model is established based on the ANSYS large-scale finite element simulation software,and the following analysis is carried out:(1)Considering the fluid structure coupling effect,different water coupling modes are adopted to study the natural vibration characteristics of the whole structure of the sluice system under two working conditions of water and no water.It is found that the natural vibration frequency of the structure under no water condition is higher than that under water condition.Using the low frequency sensor to collect the measured data of the sluice on thespot,and using the ceemdan-svd method to extract its natural working frequency,and comparing with the finite element calculation results,it is found that the calculation results of the finite element model based on the direct fluid structure coupling theory are more consistent with the modal identification results of ceemdan-svd,and the calculation accuracy and modal identification are better,which can reflect the sluice structure more accurately The working characteristics of the structure.(2)Considering the interaction of pile soil superstructure,the static analysis of the sluice structure is carried out under three working conditions,and the deformation and stress change law of the whole pile soil structure are obtained.It is found that the settlement during the impoundment period of the sluice is greater than that during the anhydrous period.The maximum settlement occurs under the design flood level,and the maximum settlement reaches 2.4mm,which meets the allowable range of the settlement specified in article 8.3.6 of SL265-2016 sluice design code.The pier and the sluice floor are respectively affected by horizontal water pressure and water weight.The stress value at the joint of the inner side of the pier and the bottom of the pier along the river is relatively large.The reason lies in the influence of water weight and horizontal water pressure in addition to the load of the self weight and its upper equipment.(3)The results show that: 1)the natural frequency of the sluice is reduced by the water in the structure,but the seismic response is increased.The results of seismic response calculated by viscoelastic boundary model are smaller than those of massless foundation model,because the influence of radiation damping effect and pile-soil contact nonlinearity is considered in the seismic calculation of foundation model with viscoelastic artificial boundary and contact nonlinearity.2)The transverse seismic response is the largest.Under the horizontal seismic action,the transverse seismic motion is the key control factor.3)The maximum displacement is at the top of bent frame,the maximum displacement is 5.1cm,the minimum displacement is at the bottom of pier,the bottom displacement is only 6.1mm,and the distribution of displacement is decreasing from top to bottom.4)The maximum main tensile stress occurs near the upper bent at the junction of the frame structure and the gate pier.The maximum main tensile stress value is 4.35 Mpa.The main tensile stress at the intersection of the frame and the gate pier is 2.25 Mpa.The main tensile stress at the gate pier is small,with an average value of about 0.289 Mpa,which does not exceed the concrete tensile strength.The research results can provide a reference for the subsequent seismic response analysis of sluice structures under the unique geological conditions in the north of Henan Province.