洱海泥炭质土动剪切模量和阻尼比试验研究  

Experimental Study on Dynamic Shear Modulus and Damping Ratio of Remoulded Peaty Soil in the Region of Erhai Lake

作　　者：刘超 屈俊童 段自侠 张翔 杨擎宇 Liu Chao;Qu Juntong;Duan Zixia;Zhang Xiang;Yang Qingyu(School of Architecture and Plannings Yunnan University,Kunming 650504,P.R.China;Yunnan Yongzhu Construction Survey and Design Co.Ltd.,Baoshan,Yunnan 678000,P.R.China)

机构地区：[1]云南大学建筑与规划学院,昆明650504 [2]云南永筑建设勘察设计有限公司,云南保山678000

出　　处：《地下空间与工程学报》2021年第5期1479-1485,共7页Chinese Journal of Underground Space and Engineering

基　　金：云南省教育厅科学研究基金项目(2019J0024);云南大学"东陆中青年骨干教师"培养计划;云南大学研究生科研创新基金项目(2019140)。

摘　　要：为探究洱海地域泥炭质土动力学特性,利用GDS动三轴仪对重塑土样进行循环加载试验,得到了一系列围压、固结比、频率控制条件下的泥炭质土动应力-应变关系曲线,分析了不同围压、固结比、频率对土体动剪切模量C_(d)、动剪切模量比G_(d)/G_(dmax)和阻尼比λ的影响规律。结果表明:动剪切模量G_(d)随剪应变γ_(d)增大而减小,γ_(d)较小时,衰减速率较小,随着γ_(d)继续增大,衰减速率先增大后减小;在同一剪应变下,G_(d)随围压、固结比增大而增大,G_(d)对频率变化表现不敏感;采用Hardin-Drnevich双曲线模型(H-D模型)对重塑泥炭质土动应力-应变曲线拟合效果较好,动剪切模量比G_(d)/G_(dmax)随剪应变γ_(d)增大而减小,围压、固结比和频率对G_(d)/G_(dmax)的衰减规律无明显的倾向性;阻尼比λ随剪应变γ_(d)增大而增大,围压对λ变化规律影响较复杂,γ_(d)较小时,λ随围压增大而减小,γ_(d)较大时,λ随围压增大而增大;固结比越大,λ越大,频率越大,λ越小,λ对频率变化表现更敏感,体现了循环加载下泥炭质土的速率效应。To explore the dynamic characteristics of peaty soil in the region of Erhai lake,cyclic loading test was conducted for remoulded sample via GDS triaxial shear equipment,and the dynamic stress-strain relation curve of peaty soil under a series of controlling conditions of confining pressure,concretion ratio and frequency was obtained,which is used to analyze the impact rules of different confining pressures,concretion ratios and frequencies on dynamic shear modulus of soil mass G_(d),dynamic shear modulus ratio G_(d)/G_(dmax) and damping ratioλ.The result shows that the dynamic shear modulus G_(d) decreases along with the increasing of shearing strain,when γ_(d) was relatively small,decay rate was relatively small.And along with continuous increasing of γ_(d),the decay rate increases after decreases;under the same shearing strain,G_(d) increases with the increase in confining pressure and concretion ratio,and G_(d) is not sensitive to the frequency variation performance;adopting Hardin-Drnevich double-curve model(H-D model)is of good imitative effect for dynamic stress-strain relation curve of remoulded peaty soil,and the dynamic shear modulus ratio G_(d)/G_(dmax) decreases with the increase of shearing strain γ_(d),while confining pressure,concretion ratio and frequency are of not significant tendency for the attenuation laws of G_(d)/G_(dmax);the damping ratio increases with the increase of shearing strain γ_(d),and the confining pressure has complex influence on change laws ofλ,when γ_(d) is relatively small,λdecreases with the increase in confining pressure,and when γ_(d) is relatively large,λincreases with the increase in confining pressure;the larger of concretion ratio,the larger ofλ,the larger of frequency,and the smaller ofλ,λis more sensitive to the frequency change,which reflectes the rate effect of peaty soil under cyclic loading.

关 键 词：重塑泥炭质土 动三轴试验 动剪切模量 Hardin-Drnevich模型 阻尼比 

分 类 号：TU431[建筑科学—岩土工程]