Warming effects on permafrost under earthquake motions and seismic stability of pile foundation of dry bridge

Abstract

A series of shaking table tests for the 1∶100 scaled model of the pile foundation in the Qingshui river Bridge along the Qinghai–Tibet Railroad were conducted on condition that the soil temperature around pile was below 0°C. The change of temperature around the pile foundation during the earthquake motions was monitored, and the warming effects on the permafrost were obtained. Applying dynamic finite element analysis method, the characteristics of seismic response of the pile foundation were analysed. In the dynamic time history analysis, the artificial seismic waves were used as the input ground motions. The effects of the peak acceleration and frequency characteristic of input ground motions on seismic stability of the pile foundation of bridges at the unstable permafrost areas of high temperature and high ice content were determined. The distributions of dynamic displacement, acceleration and earth pressure were studied and the dynamic stability of the pile foundation of bridges was evaluated.

Keywords:

• Permafrost
• Pile foundation
• Warming effects
• Temperature
• Seismic stability

This project is financially supported by the funds of the National Natural Science Foundation of China (grants no. 40902094 and no. 40974070) and the Institute of Earthquake Prediction, China Earthquake Administration (grant no. 2009A76).