The Study And Numerical Analysis Of The Seismic Performance Of Bridge In Liquefied Soil Layers

Earthquake damage survey indicated that damage of bridge is mainly caused byliquefaction. To study the failure mechanism and rules of pile foundation have importantimplications for prevention and mitigation of the damage of bridge caused by liquefaction.Based on the FLAC3Dprogram, the numerical model is established to study the dynamicresponse of the soli and the pile under the effect of the earthquake and the different conditions.The main research are as follows:1. Based on the FLAC3Dprogram, we have established the finite difference numericalmodel of dynamic soil-pile interaction in liquefying ground by using solid element, pileelement and PL-Finn model to model soil, pile and saturated sand respectively. Thecorrectness and reliability of numerical model has been verified by the dynamic response ofthe model system and a comparison with the results of shaking table test.2. The reaction rule of pile under liquefied foundation are obtained by analysis andcalculation of single pile by FLAC3Dprogram that the force of pile is the largest at thejunction of liquefaction of soil layer. We discussed the factors that affect the dynamicresponse of a single pile. These factors include overlying clayey layer、the density of theoverburden、superstructure masses and support in the form of piles. The calculation resultsshow that the internal force of the pile is decreased in overlying clayey layer, superstructuremasses and support in the form of piles have a more significant impact on the dynamicresponse of pile.3. We discussed the different force distribution between the group pile and single pile,aswell as the force distribution of low-cap pile group and elevated-cap pile group respectively.4. Discussion on the impact on gravel pile and rigidity-drain pile in liquefied ground.andthe distribution of pore pressure ratio along the depth. Analysis results shows that the twokinds of site drainage pile can obviously improve the performance of liquefactionresistance.When the pile diameter is determined, this paper discussed the effect of the pilespacing on improving the performance of the liquefied ground liquefaction resistance.