Prediction of Liquefaction Potential and Pore Water Pressure due to Earthquake   Shun-qun Li Department of Civil Engineering, Tianjin Institute of Urban Construction and Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment, Tianjin, China e-mail: lishunqun@sina.com Shou-xi Chai Department of Civil Engineering, Tianjin Institute of Urban Construction and Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment, Tianjin, China e-mail: chaishouxi@163.com Qing-xin Ren School of Civil Engineering, Shengyang Jianzhu University, Shenyang, China e-mail: renqingxin@sjzu.edu.cn Ying-hong Wang Department of Electronic & Information Engineering, Tianjin Institute of Urban Construction, Tianjin, China e-mail: wangyinghong66@sina.com
			ABSTRACT

Considering the arriving energy and modified below count of standard penetration tests (SPT) as the two key factors to evaluate liquefaction potential due to earthquake, a revised cusp catastrophe model, which can be used to describe progress of liquefaction, is established. In the proposed model, the ratio of excess hydrostatic pore water pressure due to earthquake to effective upper strata pressure is taken as the state variable. The energy function modified by earthquake duration, SPT corrected by the clay content and overburden pressure, are taken as the two control variables. Furthermore, triggering condition of liquefaction, development pattern of excess hydrostatic pore water pressure induced by cyclic loading under undrained tests, and seismic-induced damage records of liquefaction are taken into account. Compared with the conventional cusp model widely employed in engineering practice, an additional term and the three non-unity coefficients are introduced. Then, the statistical method based on the test hypothesis for controlling type ? error is utilized to determine the related parameters, bifurcated curve and transformation relationship for the two coordinate systems. It is verified by the test results that the proposed model can be used to predict liquidation potential of sites in practice more reliably.

Keywords: soil mechanics; liquefaction; cusp catastrophe model; excess hydrostatic pore water pressure

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