The Study On Earthquake Response Of Bridge Piles At Liquefiable Site

Liquefaction to the damage of bridge is an important reason, thus it is of great significant to study the process of foundation response and the failure mechanism of pile for preventing and reducing the earthquake damage to the bridge structure by liquefaction.The large shaking table scale model tests of pile-soil-bridge structure dynamic interaction at liquefiable site are performed at Civil Engineering Prevention Laboratory of Tongji University during 2002. This paper summarize the related problem in the test, such as the model design, the model parameters, the test technology, the test data and so on, and primarily study the process of site response and the characteristic of pile in this teat base on the strong motion observation and the shaking table of others.In following conclusion in site liquefaction: (1) The time of great increase of pore pressure ratio is the same with the time of the peak acceleration, according with the strong motion observation; (2) The period of surface acceleration observed in the test is lagged like the strong motion observation, and more obvious with the development of liquefied extent; (3) Due to the influence factors, such as soil composition, seismic input frequency, and so on, are too complex, this study dosen't get the accordant result in the liquefied rule along the site depth; (4) The site is more apt to liquefied under low frequency; (5) The surface acceleration response spectrum in two tests has a good consistency.In following conclusion in the respone characteristic of pile: (1) The acceleration response of the pile and the site is not very consistent;(2) the response of the pile is operated jointly by the inertia force from upper structure and the liquefaction. The response is operated by inertia force as little liquefaction, but it is common acted as full liquefaction.Generally speaking, the shaking table test as a study measure in site liquefaction is stil influenced by some factors, and can not get a entirely consistent response rule, but some are still capable of simulating partly the actual earthquake liquefiable characteristics, and has a certain repeatability. Then it is can be arrived at the conclusion that the experiments carried out in this research program is of great value to the engineering practice.