Currently, there are many countermeasures have been developed to mitigateliquefaction induced damages of buildings and to prevent liquefaction occurrence.The selection of the countermeasure against liquefaction must consider theimportance and the required performance of building structures, the cost andapplicability of the countermeasure. For example, foundation reinforcementmethod, solidification method, densification method, and ground water controllingmethod may be selected. Among them, the foundation reinforcement method isusually the top priority choice for ordinary small area and low-rise buildings whenconsidering engineering economy. In the previous studies, the applicant hasperformed several dynamic centrifuge tests to investigate the reducing effect ofpost-liquefaction settlement and tilt of low-rise building by increasing thedimensions of shallow foundation seating on liquefiable deposit. The preliminaryresults showed that the reducing effect did exist but not significant. Therefore,this project will focus on the use of deep foundation for reducing the settlementand tilt of buildings.The deep foundations that will be studied include small size pile, basement(partial floating) foundation, and slurry wall. The small size pile and basementfoundation are used for low-rise buildings. The slurry wall is used for mediumhigh-rise buildings. It is hoped to develop a more economic design strategy ofdeep foundation for mitigating liquefaction hazard to the buildings. This is a threeyear project. In the first two years, the experimental works include dynamiccentrifuge tests and laboratory tests. A series of centrifuge tests will be performedto investigate the reducing effect of post-liquefaction deformation of building byusing small size pile, basement foundation and slurry wall with variable number offloor and penetration depth into non-liquefying layer. The laboratory works willinclude the tests of physical index test, triaxial test, cyclic direct simple shear testand resonant column test on the sand used to prepare the model ground in thecentrifuge. All the parameters of the test sand will be used in the numericalcalibration work in the third year.In the third year, the numerical model for simulating the liquefied soil-pilestructure interaction will be established using FLAC2D Ver.8.0. The numericalanalysis will be a fully dynamic effective stress analysis taking the pore pressuregeneration, dissipation and nonlinear modulus degradation into account. Theparameters of the PM4Sand constitutive law will be calibrated by the laboratorytest results in the previous two years. Then, numerical tests will be carried out byvarying different design conditions and compare the calculated results with thosemeasured by dynamic centrifuge tests.Through the project, it is expected to establish a complete research data base ofthe centrifuge test, laboratory test and numerical test for investigating thereducing effect of post-liquefaction deformation of building by using deepfoundation method. It is also hoped this data base can be continually used andreferenced by anyone who is interested in this topic.
|Effective start/end date||1/08/21 → 31/07/22|
UN Sustainable Development Goals
In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):
- soil liquefaction
- deep foundation
- centrifuge model test
- settlement of building
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