Study On Influencing Factors Of Earthquake-induced Settlement Of Building On Liquefiable Sites

Liquefaction of soil is a natural phenomena,but can caused damage to engineering structures,hence,attracts intense interests both in engineering and academic communities.Ground failure caused by liquefaction is mostly demonstrated in three types,i.e.,surface oscillation,settlement,and lateral spread.The nature of liquefaction ground failure is liquefaction-induced large deformation of soil.Physically,soil liquefying is a complex nonlinear process,and can increase the pore-water pressure in soil so that it reduces the effective stress and ground bearing capacity.In reality,large deformation generally causes building misfunctional and damaged.During engineering site planning,liquefiable ground can be inevitably avoided.To reasonably describe the influencing factors on building settlement in order to make a reliable prediction paves a good way for engineering liquefaction protection.Presently,the main technique to simulate large deformation induced by soil liquefaction is using numerical simulation.In this dissertation,the software of Fast Lagrangian Analysis of Continua(FLAC3D)which can simulate large deformation is adopted to model a building structure sitting on layered liquefiable ground which suffers seismic loading.By parameters setting,the influencing factors of building settlement as well their influencing modes are systematically discussed.The main work and obtained outcomes can be outlined as follows.1.Based on the conceptual model of liquefaction-induced settlement of building,the settlements of site liquefaction and nonliquefaction are comparatively analyzed by selecting reasonable modelling parameters.The results indicate building settlement on liquefied site is remarkably larger than nonliquefied site.2.The influence of overlying soil layer characteristic parameters,including layer thickness,shear wave velocity and soil cohesion,on liquefaction-induced settlement of buildings is studied,that the influence rules of overburden characteristics on building settlement caused by site liquefaction are analyzed.3.The influence of liquefiable layer characteristics parameters,including layer thickness,shear wave velocity and permeability coefficient,on the liquefaction-induced settlement of the building are investigated.Through simulating the increasing and dissipation of the pore-water pressure during soil liquefaction,the influence rules of the liquefiable layer characteristics on building settlement are presented.4.The influence of building geometric dimensions,including numbers of floors and size of building foundation,on the liquefaction-induced settlement of buildings are explored,and the influence rules of building characteristics on the liquefaction-induced settlement are discussed.