CAJ | 학술논문

利用振动台进行了在地震激励下冻土、可液化砂土与钢管桩之间的相互作用模拟试验研究。试验设计柔性模型箱装填土体以模拟边界影响，通过配比试验制备混凝土砂浆模拟上覆冻土层，采用饱和砂土作为液化土，利用顶部附加集中质量的方法模拟钢管桩的惯性荷载。试验过程中选取调幅地震波模拟地震激励，通过实时测量桩的应变、桩/冻土位移和砂土内的孔隙水压力等方面的数据，分析冻土层覆盖下砂土的液化情况和与之对应的桩基动力反应情况。试验结果显示：在地基液化发生前，冻土层可以给桩基提供一定的侧向约束，有利于提高其承载力并抑制其侧向变形；然而一旦出现液化，冻土层则可能增强地基液化的趋势，导致桩基承载性能下降。
이용진동태진행료재지진격려하동토、가액화사토여강관장지간적상호작용모의시험연구。시험설계유성모형상장전토체이모의변계영향，통과배비시험제비혼응토사장모의상복동토층，채용포화사토작위액화토，이용정부부가집중질량적방법모의강관장적관성하재。시험과정중선취조폭지진파모의지진격려，통과실시측량장적응변、장/동토위이화사토내적공극수압력등방면적수거，분석동토층복개하사토적액화정황화여지대응적장기동력반응정황。시험결과현시：재지기액화발생전，동토층가이급장기제공일정적측향약속，유리우제고기승재력병억제기측향변형；연이일단출현액화，동토층칙가능증강지기액화적추세，도치장기승재성능하강。
The seismic responses of a single steel-pipe pile built in the frozen crust and the liquefiable sand soil were studied by shaking table tests. A flexible soil container was designed and used to construct the soil profile in order to minimize the boundary effect. The frozen crust was simulated through the mortar which was made of cement, sand and water by the mixture ratio. Liquefaction can occur in the saturated sand soil beneath the frozen crust. A lumped mass was exerted at the top of the pile to satisfy the inertia con-ditions. During the tests, several amplitude-scaled ground motions were chosen as input seismic waves. The liquefying levels of the sat-urated sand soil and the dynamic responses of the pile can be analyzed via the measured real-time data including strains of the pile, dis-placements between the pile and the frozen crust and pore water pressures in the sand. Experimental results show that before liquefac-tion occurs, the frozen crust can provide a lateral constraint, and thus improve the load bearing capacity of the pile and suppress its lat-eral deformation. It is also found that once liquefaction occurs, the frozen crust may further strengthen this tendency and deteriorate the performance of the pile.