| Our country is in an area with frequent earthquakes,with various seismic zones of different sizes.In these seismic zones,there are various types of infrastructure related to our national economy and people’s livelihood.On the eastern coastal areas and the banks of inland rivers,many natural liquefaction lateral expansion fields have been formed.Once an earthquake comes,it will cause huge economic losses and threaten the safety of people’s lives and property.Effectively preventing and reducing earthquake damage in such fields has important practical significance.Pile foundation has the characteristics of simple construction and high bearing capacity,and is widely used in various infrastructure construction in our country.However,pile foundations do not have advantages when resisting horizontal loads.Especially in the liquefied lateral expansion site,the pile foundation will be damaged due to the excessive lateral force generated by the lateral flow of the liquefied layer.The anti-liquefaction rigid-drainage pile is a new type of pile that has both high bearing capacity and drainage function.At present,most researches on the anti-liquefaction rigid-drainage piles focus on the single piles and pile groups in the horizontal field,and the related researches on the laterally spreading field of liquefaction are still not enough.At the same time,the seismic response under the combined action of the superstructure is still in a blank.In view of this,this paper mainly discusses the relative dynamic response of the rigid-drainage pile-superstructure-quay wall system in the liquefied lateral spreading field through the shaking table test.Provide certain experimental data for the promotion and production of rigid-drainage pile.The main research methods and contents are as follows:(1)Carry out a series of 1-g shaking table tests,set ordinary square piles as a comparison group,and verify the anti-liquefaction performance of rigid-drainage pile by responding to changes in pore pressure and acceleration in the sand stratum.The post-earthquake ground settlement analysis and the horizontal displacement analysis of the quay wall verify the restriction of the lateral expansion under the reinforcement of rigid-drainage piles.Through the relevant test results,it can be found that,except for the complete liquefaction of the top foundation soil under the action of the large earthquake(PGA=0.2 g),the foundation reinforced by rigid-drainage piles has no obvious liquefaction phenomenon.However,the ordinary pile-reinforced foundation has already produced obvious liquefaction phenomenon during the moderate earthquake(PGA=0.1g).At the same time,the performance of foundation settlement and horizontal displacement under the reinforcement of rigid-drainage piles is also better than that of ordinary piles.(2)The dynamic response test results of the superstructure under different piles are used to verify the improvement of the stability and safety of the superstructure by the reinforcement of rigid drainage piles.It mainly includes: verifying the stability of the superstructure under the reinforcement of rigid-drainage piles through the acceleration response and displacement response of the superstructure;At the same time,the bending moment change of the superstructure is proved to verify the safety improvement of the superstructure under the reinforcement of rigid drainage piles.The experimental results prove that the rigid drainage piles can effectively reduce the swing amplitude of the superstructure(the acceleration amplification factor decreases by 39.1%) and the peak bending moment.It is proved that the reinforcement of rigid drainage piles is more effective.In addition,the difference in the dynamic response of the frontal superstructure under the action of seismic waves under different near and far sites is also discussed.(3)The influence of different influencing factors on the rigid drainage pile-superstructure-quay wall system can be studied by changing different cases.Mainly include: in the loading scheme,increase the amplitude of the seismic wave from PGA=0.05 g to PGA=0.2 g and increase the two types of seismic waves under the far and near sites;In the design factors,change the pile gap(50 mm and 75 mm)and the pile-retaining wall gap(60 mm and 125 mm).The experimental results show that rigid-drainage piles can effectively eliminate the effects of changes in relative density and pile spacing.When increasing the pile-retaining wall spacing,it is helpful to reduce ground settlement,but it is not conducive to restricting the horizontal displacement development of the quay wall. |
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