贮灰场沉积粉煤灰动力特性试验研究  

Experimental Study on Dynamic Characteristics of Fly Ash Deposited in Ash Storage Field

作　　者：刘少辉 梁志超 李俊生 成勇龙 李伟[1] LIU Shaohui;LIANG Zhichao;LI Junsheng;CHENG Yonglong;LI Wei(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《水利与建筑工程学报》2021年第5期52-57,共6页Journal of Water Resources and Architectural Engineering

基　　金：国家自然科学基金面上项目(51978572)。

摘　　要：贮灰场沉积粉煤灰的动力特性对评价挡灰坝在地震动荷载作用下的稳定性至关重要。通过动三轴仪对两种不同干密度的沉积粉煤灰进行了三轴试验,探究了沉积粉煤灰的动应力-动应变关系、动模量、阻尼比、动孔压和动强度的变化规律。研究结果表明:不同干密度的粉煤灰动应力-动应变曲线基本呈双曲线型,与土的应力-应变曲线相似,呈弱硬化型。干密度大的试样相应的动模量越大。相同干密度下,不同围压下的阻尼比规律不明显,但阻尼比随着动应变的变化趋势符合一般土常见的规律。动应力越大,试样破坏所需的振动次数越小,且动剪应力比也越大。动孔压水平随振次的变化不大,且与振次比的关系可以归一化。同时,得到了两种沉积粉煤灰的总强度指标和有效应力指标。The dynamic characteristics of fly ash deposited in the ash storage yard is very important to evaluate the stability of the ash dam under the action of ground motion loads. In this paper,a triaxial test was carried out on two different dry densities of deposited fly ash with a dynamic triaxial instrument,and the dynamic stress-dynamic strain relationship,dynamic modulus,damping ratio,dynamic pore pressure and dynamic strength of the deposited fly ash were explored. The research results show that the dynamic stress-dynamic strain curves of fly ash with different dry densities are basically hyperbolic,which is similar to the stress-strain curve of soil,showing a weak hardening type. A specimen with a higher dry density corresponds to a larger dynamic modulus. Under the same dry density,the law of damping ratio under different confining pressures is not obvious,but the change trend of damping ratio with dynamic strain conforms to the common law of general soil. The greater the dynamic stress,the smaller the number of vibrations required for specimen failure,and the greater the dynamic shear stress ratio. The dynamic pore pressure level does not change much with the vibration frequency,and the relationship with the vibration frequency ratio can be normalized. At the same time,the total strength index and effective stress index of two kinds of deposited fly ash are obtained.

关 键 词：沉积粉煤灰 动模量 阻尼比 动强度 动孔压 

分 类 号：TU435[建筑科学—岩土工程]