常规土类动剪切模量阻尼比超越概率计算方法

Calculation Method for the Exceedance Probabilities of Dynamic Shear Modulus Ratio and Damping Ratio of Conventional Soils

摘要:

土的动剪切模量比和阻尼比是土层地震反应分析、工程场地地震安全性评价和地震小区划工作中的必备参数,但其不确定性显著,对地震动和抗震设计影响很大。本文以我国常规土类动剪切模量比和阻尼比与剪应变非线性关系试验为基础,研究考虑这两个动力参数变异性下其超越概率的计算方法。方法包括了试验数据的整理、超越概率的计算以及两个动力参数和超越概率关系模拟等几个步骤,最后给出了我国常规土类动剪切模量比和阻尼比超越概率的计算公式,为我国基于概率和可靠度思想的工程地震安全风险评估提供了一定基础。

Abstract:

The dynamic shear modulus ratio and damping ratio are the necessary parameters for analysis of ground motion, seismic safety evaluation of engineering sites, and seismic microzonation. But the uncer- tainty of two parameters is great and have remarkable effects on the ground motion and design spectrum. In this paper, basing on the testing results of nonlinear relationship between shear strain and dynamic shear modulus ratio, damping ratio for conventional soils, the calculation method of their exceedance probabilities is presented. The method includes the statistics of testing data, calculation of the ex- ceedance probability and the curve fitting process. The calculation equation for the exceedance probabili- ties of the dynamic shear modulus ratio and damping ratio are proposed and the results may lay the foun- dation for seismic safety risk assessment basing on probability and reliability theory.