基于升温作用的冻土动剪切模量与阻尼比试验研究  

Study on the dynamic shear modulus and damping ratio of frozen soil based on the heating effects

作　　者：温董瑶 蒋宁山[1,2] WEN Dongyao;JIANG Ningshan(School of Civil Engineering,Qinghai University,Xining 810016,China;Qinghai Key Laboratory of Building Energy-saving Materials and Engineering Safety,Xining 810016,China)

机构地区：[1]青海大学土木工程学院,青海西宁810016 [2]青海省建筑节能材料与工程安全重点实验室,青海西宁810016

出　　处：《青海大学学报》2021年第2期56-61,共6页Journal of Qinghai University

基　　金：青海省科学技术厅项目(2015-ZJ-722,2018-ZJ-T01)。

摘　　要：为了解升温冻土在动荷载作用下动力特性变化规律,探究Hardin-Drnevich双曲线模型对冻土动力特性的适用性,以青海省G101公路沿线冻土为研究对象,用GDS动三轴系统模拟土体在实际情况下的固结及不同初始负温度环境梯度升温的过程,研究冻土阻尼比和动剪切模量随温度的变化规律。结果表明:负温对冻土阻尼比和动剪切模量影响显著。阻尼比随梯度升温的增大而增大,随初始负温度环境的降低而减小,随动应变的增加而增大;恒温冻土阻尼比的范围为0~0.05,升温冻土阻尼比范围为0~1;Hardin-Drnevich双曲线模型能够较好地描述阻尼比与动应变变化规律。动剪切模量范围为0~20 MPa,动剪切模量随梯度升温的增加而减小,随初始负温度环境的降低而增大,随动应变的增加而减小;动应变小于1%,动剪切模量急剧降低;动应变大于1%,动剪切模量缓慢降低,最终趋于平稳。本研究结果对寒区冻土公路在升温作用下的动力稳定性评估及路基抗振的性能设计具有参考作用。In order to understand the dynamic characteristics of warming frozen soil under the dynamic load and explore the applicability of hyperbolic model Hardin-Drnevich to the dynamic characteristics of frozen soil,this study takes the frozen soil along G101 highway in Qinghai province as research object.GDS dynamic triaxial system is used to simulate the consolidation of soil under the actual conditions and the process of gradient with an environment of different initial negative tempe rature so as to study the variation of damping ratio and dynamic shear modulus of frozen soil with temperature.The results show that negative temperature has a significant effect on the damping ratio and dynamic shear modulus of frozen soil.The damping ratio increases with the increase of gradient heating,decreases with the decrease of the environment of initial negative temperature and increases with the increase of dynamic strain;the damping ratio of constant temperature frozen soil ranges from 0-0.05,and that of warming frozen soil ranges from 0-1;Hardin-Drnevich hyperbolic model can better describe the damping ratio and dynamic strain.The dynamic shear modulus ranges from 0-20 MPa which decreases with the increase of the gradient heating value,increases with the decrease of the environment of initial negative temperature of and decreases with the increase of dynamic strain;the dynamic shear modulus decreases sharply when the dynamic strain is less than 1%;the dynamic shear modulus decreases slowly and finally tends to be stable when the dynamic strain is greater than 1%.The results of this study can be used as a reference for the evaluation of dynamic stability and the design of subgrade seismic performance of frozen soil highway in the cold regions under the heating effects.

关 键 词：梯度升温 初始负温度环境 动应变 阻尼比 动剪切模量 

分 类 号：TU411.8[建筑科学—岩土工程]