An Investigation Into the Lateral Resistance of Liquefied Soil

在地震中，由于涉及到水平加速度，结构必须由基础提供一定的横向约束。对于嵌入液化易感土壤中的桩，这种横向支撑要求可以主导基础的设计。本项目的目的是评估在强烈地震中造成无黏性土壤液化的深地基上施加的横向土壤阻力。目的是提高对液化土横向支撑的认识，并提供更好的估计：目前在设计中完全忽略了液化土的横向阻力，导致建筑基础保守，因此更昂贵。初步研究表明，即使是少量的土壤阻力也会导致更经济的设计。因此，侧向土阻力——尽管它预计很低——应该量化并包括在设计中。本研究项目包括在实验室控制条件下的大规模（接近全尺寸）实验研究。它由一个大型填砂液化罐和一个仪器轴组成，其中装满液化的沙子，水平加速以测量液化土壤的侧向阻力。本试验并不试图模拟桩的完整行为。一旦测量和了解了液化区正确的侧移土阻力，就可以对整个侧移行为进行数值模拟。＊＊＊

9223092 Brown During an earthquake, a structure must be provided with some lateral restraint by the foundation because of the horizontal accelerations involved. For piles embedded in liquefaction-susceptible soils, this lateral support requirement can dominate the design of the foundation. The objective of this project is to evaluate the lateral soil resistance exerted on a deep foundation during a strong earthquake which causes the cohesionless soil to liquefy. The aim is to improve the understanding, and provide a better estimate, of the lateral support provided by liquefied soil: currently the lateral resistance of liquefied soil is completely neglected in design, leading to a conservative and therefore more expensive building foundation. Preliminary studies show that even small amounts of soil resistance result in a more economic design. Therefore the lateral soil resistance -- although it is expected to be low -- should be quantified and included in the design. This research project includes a large-scale (nearly full scale) experimental study under laboratory controlled conditions. It consists of a large sand-filled liquefaction tank, in which the sand in liquefied, and an instrumented shaft is accelerated horizontally to measure the lateral resistance of the liquefied soil. This experiment does not attempt to model the complete pile behavior. The complete lateral behavior is modeled numerically once the correct lateral soil resistance in the liquefied zone is measured and understood. ***