Study On The Pile-soil-aqueduct Interaction By Pseudo-dynamic Test And Computational Analysis

At the end of the20th century, the construction of the inter-basin water transferproject had become the important means to solve the problem of uneven distributionof water resources in China. With the construction of the South-to-North WaterDiversion Project in China, the large aqueduct structures which have thecharacteristics of large flow and large span are constantly emerging. The seismicproblem of large aqueduct structure has become a research hotspot in the aseismicengineering field.It is of important significance to study on the method of aseismic calculation ofthe large aqueduct structure, which could meet the need of the aseismic design oflarge aqueduct structures in the South-to-North Water Diversion Project as well asprovide certain basis to establish the theory and method of the aseismic design ofaqueduct structure.The laws of the transverse seismic responses of the aqueduct structure, thetransverse aseismic calculation model of aqueduct structure, and the influence laws ofthe height of the piers on the transverse dynamic characteristics and the transverseseismic responses of aqueduct structures were primary studied in this dissertation.The main work and achievements are as follows:(1) The original reason MDOF substructure pseudo-dynamic model tests of theaqueduct structure were carried out and the laws of the transverse seismic responsesof the soil-piles-aqueduct structure-water dynamic interaction system were studied.The results of the tests showed that the peak values of the transverse seismicresponses of aqueduct structure under the action of different test seicmic waves whichhad the same peak acceleration had obvious differences. At the same time, thefluid-structure coupling dynamic interaction may be reduce or increase the peakvalues of the transverse seismic responses of aqueduct structure and the influence lawis related to the frequency modulation effect of water and the hydrodynamic pressureof water. In addition, with the increase of peak acceleration of the input seismicwaves, the development of plasticity of the soil around piles changed the stiffnesscharacteristics of the test model and eventually made the waveform and peak value ofthe time history curves of the transverse seismic responses of aqueduct structureexhibit obvious difference. (2) The integrated finite element calculation model of pseudo-dynamic test modelwas established. It was used to the simulation calculation of the transverse seismicresponses of the pseudo-dynamic test model in this dissertation. The calculationresults were compared with the results of pseudo-dynamic tests. It demonstrated thatthe integrated finite element calculation model of the pseudo-dynamic test modelcould estimate the transverse seismic responses of the test model and could wellreflect the effect of water on the transverse seismic responses of the test model. At thesame time, another two integrated finite element calculation models ofpseudo-dynamic test model were established. The effects of the movement of soillayer and the calculation range of the soil layer on the transverse seismic responses ofaqueduct structure were studied. The results showed that the pseudo-dynamic testmethod could better reflect the laws of the transverse seismic responses of theaqueduct structure，and the error of peak values of the transverse seismic responses ofthe aqueduct structure obtained by the pseudo-dynamic test was smell.(3) The simplified finite element calculation model of the aqueduct structurewas established. The transverse seismic responses of the pseudo-dynamic test modelwere calculated, which adopted the simplified finite element calculation model. Thecalculation results were compared with the results of pseudo-dynamic tests. Itdemonstrated that the simplified finite element calculation model could approximatelyestimate the transverse seismic responses of the test model and could well reflect theeffect of water on the transverse seismic responses of the test model. At the same time,the calculation results of simplified finite element calculation model with free fieldinput were compared with the results of simplified finite element calculation modelwith earthquake inertia force input. The results showed that there would be a certainerror in estimating the peak values of the transverse seismic responses of the testmodel with earthquake inertia force input, but still able to better reflect the laws oftransverse seismic responses of the test model. In addition, the calculation results ofsimplified finite element calculation model with free field input were compared withthe results of the third integrated finite element calculation model of thepseudo-dynamic test model. The results showed that the waveform, peak value and thefrequence spectrum characteristics of the transverse seismic responses of the aqueductstructure obtained by the above two models had a certain difference, but the laws ofthe transverse seismic responses of the aqueduct structure obtained by the above twomodels were consistent.(4) In consideration of the fluid-structure coupling dynamic interaction with Housner spring-mass simplified model and the nonlinear soil-pile dynamic interactionwith soil-pile nonlinear dynamic Winkler foundation beam simplified model, anaseismic simplified calculation model which could calculate the transverse seismicresponses of the aqueduct structure system was proposed in this dissertation. Thetransverse seismic responses of the pseudo-dynamic test model were calculated,which adopted the simplified calculation model. The calculation results werecompared with the results of pseudo-dynamic tests. It demonstrated that the simplifiedmodel of the pseudo-dynamic test model could approximately estimate the transverseseismic responses of the test model and could well reflect the effect of water on thetransverse seismic responses of the test model. At the same time, the calculationresults of simplified calculation model with free field input were compared with theresults of simplified calculation model with earthquake inertia force input. The resultsshowed that there would be a certain error in estimating the peak values of thetransverse seismic responses of the test model with earthquake inertia force input, butstill able to better reflect the laws of transverse seismic responses of the test model. Inaddition, the calculation results of simplified calculation model with free field inputwere compared with the results of the third integrated finite element calculationmodel of the pseudo-dynamic test model. The results showed that the waveform, peakvalue and the frequence spectrum characteristics of the transverse seismic responsesof the aqueduct structure obtained by the above two models had a certain difference,but the laws of the transverse seismic responses of the aqueduct structure obtained bythe above two models were consistent.(5) By using the integrated finite element calculation model of aqueductstructure, the simplified finite element calculation model of aqueduct structure andthe transverse aseismic simplified calculation model of aqueduct structure, theinfluence laws of the height of the piers on the transverse dynamic characteristics andthe transverse seismic responses of the rectangular aqueduct structures were studiedthrough the calculation under the condition of the cross-section of the pier and otherparameters basically unchanged. The results showed that the fundamental frequencyof transverse vibration and the peak value of transverse dynamic responses of the keyparts of the aqueduct structure had a degressive trend with the increase of pier height.Finally, the problems requiring further studies are discussed.