A Study on the Flat DMT-based Method for Evaluating Liquefaction Resistance of Soils
2009
Hochschulschrift
Zugriff:
97
The extensive ground surface settlement, tilt and overturn of buildings, and floatation of buried structures were caused by the Niigata earthquake in 1964. In the same year, many foundations of bridges were damaged by the liquefaction-induced ground movements caused by the Alaska earthquake in United States. Also, in the 1999 Chi-Chi earthquake of Taiwan, the severe liquefaction-induced hazards were extensively observed in many areas. The problem how to accurately predict the liquefaction potential of soils caused by earthquake has received much attention from geotechnical engineers and been the crucial objective of the academia. The liquefaction evaluation of soil is a complicated problem. According to the previous studies, the liquefaction resistance of soil would be affected by a large number of factors such as relative density (Dr), effective overburdened stress, fines content (FC), coefficient of earth pressure at rest (K0), prestraining, over-consolidation ratio (OCR), and aging. It would be very difficult to incorporate all the factors into the liquefaction evaluation. At present, the simplified evaluation methods of standard penetration test (SPT) and cone penetration test (CPT) are commonly used by engineers. Basically, the two methods directly employ the measured SPT blow count (N value) and cone resistance (qc) to calculate the liquefaction resistance of soils. Although the SPT- and CPT-based liquefaction evaluation methods are extensively adopted by the engineer, it is desirable to develop additional simplified liquefaction evaluation method in practice. The horizontal stress index (KD) measured in DMT test is not only sensitive to the above-mentioned factors influencing the liquefaction resistance, but also involves to the in-situ horizontal and vertical stress conditions. In addition, the dilatomater modulus (ED) is representative to the pressure corresponding to the limited deformation of the soil when the soil is subjected to the horizontal pressure. To this end, this study attempts to develop a DMT-based simplified liquefaction evaluation method. This study adopts the horizontal stress index (KD) and dilatometer modulus (ED) measured in the DMT as the input parameter of the simplified liquefaction evaluation method to calculate the liquefaction resistance of soils. First, the flat dilatometer test (DMT), standard penetration test (SPT), and cone penetration test (CPT) were conducted side-by-side at six sites for establishing the correlations between horizontal stress index and dilatometer modulus and blow counts. Subsequently, a simplified model for evaluating liquefaction resistance of soils was developed. Then, a number of worldwide earthquake-induced liquefaction cases are collected and used to validate the accuracy of the developed model. The analysis results show that the capability of the model in estimating the liquefaction resistance of soils is validated. This model can be integrated with the existing models to completely evaluate the liquefaction resistance of soils.
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A Study on the Flat DMT-based Method for Evaluating Liquefaction Resistance of Soils
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Autor/in / Beteiligte Person: | Tsai, Pai-Hsiang ; 蔡百祥 |
Link: | |
Veröffentlichung: | 2009 |
Medientyp: | Hochschulschrift |
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