Influencing Factors and New Calculation Formulae for the Stress Reduction Coefficient

ABSTRACT

The new formulae with three factors and one factor for calculating the stress reduction coefficient r_d at depths of 0–50 m are proposed in this paper. A more reliable database of r_d curves is established using models for actual sites, the corresponding real seismic records from the KiK-net downhole array. Then, a quantitative analysis of the factors influencing r_d is performed, and the important factors affecting r_d are reasonably selected. The basic pattern of the r_d curves and their unified mathematical expression for depths of 0–50 m are determined and the three-factor and one-factor formulae for calculating r_d are presented.

KEYWORDS:

• Dynamic stress reduction coefficient
• r_d curve
• liquefaction evaluation
• three-factor formula
• one-factor formula

Additional information

Funding

This research is jointly supported by the Scientific Research Fund of the Institute of Engineering Mechanics, China Earthquake Administration [Grant No. 2019A01] and the National Key Research and Development Plan for International Cooperation [Grant No. 2016YFE0105500]. This research is based on the seismic motion records and site information of KiK-net database provided by NIED (National Research Institute for Earth Science and Disaster Resilience).