Evaluation method for the liquefaction potential using the standard penetration test value based on the CPTU soil behavior type index

Abstract

Taking the project of the Su-xin highway treated by using the resonant compaction method as the reference, a new method for the evaluation of liquefaction potential is proposed based on the piezocone penetration test (CPTU) and the standard penetration test (SPT). The soil behavior type index (I c ) obtained from CPTUs and the standard penetration test index (N 63.5 ), obtained from SPTs, are analyzed for saturated silty sand and silt. The analysis result reveals a linear relationship between N 63.5 and I c , given by N63.5=-18.8Ic+52.0. The larger the value of I c is, the greater the viscosity of soil is, and the smaller the value of N 63.5 is. According to the method, liquefaction assessment of saturated silty sand and silt foundation can be conducted by using N 63.5 based on the Code of Seismic Design of Building. N 63.5 is expressed by a single I c , which is calculated from the CPTU data. Compared with existing evaluation methods, this method can provide continuous standard penetration test values, moreover, this method involves a simple calculation, and the results obtained using the method are reliable.