Liquefied Deformation Analysis Of Large Caisson Wharf Foundation And Reinforcement Measures

With the rapid advance of economic globalization and the rapid increase of internationalimport and export trade, the port terminal has played an increasingly important role in theconnection between nations and regions. Because of its excellent integrity, good seismicperformance and less underwater work caisson wharf is widely used in coastal area of goodfoundation. In recent years, large and strong earthquakes have occurred frequently in theword, causing significant damage to the coastal port engineering and bringing painfulmemories and serious economic losses to the countries and the people. Based on groundliquefaction has become the main reason of the port engineering for earthquake damage.Therefore, port structure foundation liquefaction characteristics, liquefaction failuremechanism exploration, seismic reinforcement measures and liquefied foundation researchare the focus of the seismic stability analysis in port structures recently. Taking the Kobe PortTerminal in the Great Hanshin earthquake as the background to use FLAC3D finite differencenumerical simulation software to make a nonlinear dynamic analysis. The main work isintroduced as follows:(1) To summarize the liquefaction evaluation of saturated sand, analysis methods andmechanism of compacted gravel pile in strengthening liquefaction foundation, after thatrecalled caisson wharf seismic research and development both at home and abroad, andpointed out the development trend of caisson wharf seismic research in the future.(2) Based on the Byrne constitutive relation built-in FLAC3D for sand liquefactionmodel and considered the structure-soil-water interactions affect to make a nonlineareffective stress analysis of the three-dimensional of caisson wharf to which simulate thedynamic characteristics of wharf structure and foundation soil under seismic loading, that isrecorded the different monitoring points at residual displacement, excess pore waterpressure-time curve, acceleration response curve and effective stress response curve, toexplore the mechanism of caisson liquefaction damage and determine the weakness ofseismic reinforcement. Through the three conditions of replacement sand liquefied, backfillsand liquefied and both liquefied were compared to give a quantitative analysis in different locations liquefied that affect caisson stability. After the analysis, it can be concluded someuseful suggestions to the caisson wharf seismic design and seismic strengthen measures.(3) After the second chapter of the acceleration response analysis, more in-depth studyof the caissons under free field conditions, different strength, different dimension seismicwaves with different groundwater under the horizontal and vertical acceleration response. Thestudy found that to consider vertical seismic waves and do not consider vertical seismic wave,the soil acceleration response performed differently. It is pointed out that the current seismicdesign treatment methods of the vertical acceleration have some shortcomings.(4) To use the FLAC3D solid pile element to simulate the foundation treatment wherethe backfill sand at the bottom of caisson, the backfill sand at the toe of caisson andreplacement sand behind the caisson and evaluate the foundation reinforcement effect fromthe residual deformation of caisson foundation, liquefaction area and pore water pressure.