SOIL LIQUEFACTION INDUCED MANHOLE UPLIFT AND NOVEL REMEDIATION

Abstract

In areas vulnerable to soil liquefaction during earthquakes, uplift of underground structures has brought devastating damages to human community, and manhole uplift is one of the typical. In industry, safety factor was proposed to assess manholes stability during soil liquefaction for decades based on analysis of component forces acting on a manhole. This study reexamined the analysis of component forces both theoretically, experimentally, and numerically. It was found that sidewall friction, which was assumed to be 0 previously, plays a substantial role in the completeness of the manhole equilibrium. Besides, the dynamic interaction of component force acting on a manhole was explored by specifically designed centrifuge experiments. Lastly, based on the renewed understanding to manholes uplift mechanism, a series of mitigation measures, specifically designed for existing manholes, were proposed and validated. Such measures enrich the options for existing manhole remediation in terms of restraining uplift risks in future earthquakes.