Estimating liquefaction-induced ground settlements from CPT for level ground

Abstract

An integrated approach to estimate liquefaction-induced ground settlements using CPT data for sites with level ground is presented. The approach combines an existing CPT-based method to estimate liquefaction resistance with laboratory test results on clean sand to evaluate the liquefaction-induced volumetric strains for sandy and silty soils. The proposed method was used to estimate the settlements at both the Marina District and Treasure Island sites damaged by liquefaction during the Loma Prieta, California, earthquake on 17 October 1989. Good agreement between the calculated and measured liquefaction-induced ground settlements was found. The major factors that affect the estimation of liquefaction-induced ground settlements are also discussed in detail. The recommendations for taking the effects of these factors into account in estimating liquefaction-induced ground settlements using the proposed CPT-based approach are presented. It is suggested that the proposed method may be used to estimate liquefaction-induced settlements for low- to medium-risk projects and also to provide preliminary estimates for higher risk projects.Key words: liquefaction, settlements, earthquake, sand, in situ testing.

CPTu Simplified Stress-Based Model for Evaluating Soil Liquefaction Potential

“…The percentage change in CRR (in reference to the CRR calculated from Eq. (6) 53 For all data points shown in Fig. 11, the percentage change in CRR strongly correlates with the magnitude of Bq, as re‰ected in the extremely high r 2 .…”

“…13 and the seismic parameters of Mw＝7.4 and amax＝0.40 g, liquefaction potential in terms of factor of safety is calculated with both the proposed model and the RW/Zhang method, which is the shorthand of the Robertson and Wride (1998) method as updated in Zhang et al (2002). Figure 14 shows the results of this analysis.…”

“…Among these CPT-based models or methods, that developed by Robertson and Wride (1998) and updated in Zhang et al (2002) is arguably the most widely used. This method is a deterministic model, meaning that the soil and seismic parameters are treated as if they were not subject to random variations.…”

Analysis on Settlement of Soil Deposits Following Liquefaction During Earthquakes

“…However, the focus of all those studies was on clean sand. The studies were then extended, and the procedures for estimating the liquefaction-induced settlement of silty sand deposits from cone penetration tests (CPT) were examined by Zhang et al (2002). The eŠect of grain compositions on the volume changes of saturated soil specimens due to the drainage of excess pore water following undrained irregular cyclic triaxial tests was examined by Tsukamoto et al (2004b), and a procedure was developed for estimating the post-liquefaction settlement of silty sand deposits from the basic physical properties of relative density.…”

Risk assessment of liquefaction-induced hazards using Bayesian network based on standard penetration test data

“…Although recent advances in physical model experiment and 25 computational modeling of liquefaction-induced ground deformation were quite promising, challenges 26 remain yet on the critical unresolved problems, such as, without a perfect physical numerical model for 27 totally describing the complicated mechanic characteristics of soils, high expense and difficulty associated with obtaining and testing high quality undisturbed samples of loose sandy soils, 1 time-consuming, and large costs of manpower and material resources. Therefore, empirical liquefaction 2 models based on a historical database compiled from historical earthquakes are likely best suited to 3 provide a simple, reliable, and direct way to assess liquefaction-induced hazards for many years to come 4 in the field of geotechnical earthquake engineering (Zhang et al 2002). As for the empirical liquefaction 5 method, liquefaction potential index (LPI) has been used to characterize liquefaction-induced hazards 6 worldwide that is proposed by Iwasaki et al (1982).…”