摘要
为揭示饱和砂土在不同加载频率作用下剪应变发展特性和剪切模量的衰退特性,基于竖向-扭转耦合剪切仪设备,开展了不同加载频率下不同相对密实度的饱和砂土不排水循环扭剪试验,采用模量衰退指数δ对饱和砂土的剪切模量衰退特性进行量化,分析饱和砂土的剪应变发展特性及剪切模量衰退特性等。结果表明:随着加载频率f的增大,饱和砂土的剪胀剪缩特性逐渐减小,达到初始液化的循环次数NL逐渐增加;且f的增大抑制了剪切应变的发展。相近剪应变水平下的δ随f的增大而减小,并提出一种基于剪应变的模量衰退模型预测δ。剪切模量G随着循环次数N和孔压比ru的增大而逐渐衰减,相同ru和N水平下,G随f的增大而增大。加载频率f对δ-ru与δ-N/NL关系的影响较小,并基于Matasovic模型建立δ-ru新模型,将Seed单参数孔压模型代入新模型可得到δ-N/NL新模型,该模型可以较好地预测本文试验数据且适用性较好。
In order to reveal shear strain development characteristics and shear modulus decline characteristics of saturated sand under different loading frequencies,undrained cyclic torsional shear tests of saturated sand with different relative densities under different loading frequencies are carried out on the basis of vertical-torsional coupled shear apparatus,and the modulus decline indexδis used to quantify shear modulus decline characteristics of saturated sand,and shear strain development characteristics and shear modulus decline characteristics of saturated sand are analysed.The results show that shear expansion of saturated sand decreases gradually with increasing loading frequency f,and the number of cycles NL of initial liquefaction increases gradually;and the increase of f inhibits the development of strain in saturated sand.δat similar shear strain levels decreases with increasing f,and a modulus decay model based on shear strain is proposed to predictδ.Shear modulus G gradually decays with the increase of the number of cycles N and pore pressure ratio ru,and G increase with the increase of f at the same ru and N level.The effect of loading frequency f on the relationship betweenδ-ru andδ-N/NL is small,and a new model ofδ-ru is established based on Matasovic model,and a new model ofδ-N/NL can be obtained by substituting one-parameter pore-pressure seed model into the new model,which can predict the experimental data better in this paper and has a better applicability.
作者
辛双龙
王炳辉
张雷
张云飞
许成顺
金丹丹
XIN Shuanglong;WANG Binghui;ZHANG Lei;ZHANG Yunfei;XU Chengshun;JIN Dandan(School of Civil Engineering and Architecture,Jiangsu University of Science and Technology,Zhenjiang 212100,China;College of Civil Engineering and Architecture,Zhejiang University of Water Resources and Electric Power,Hangzhou 310018,China;Faculty of Architecture,Civil and Transportation Engineering,Beijing University of Technology,Beijing 100124,China;School of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,China)
出处
《岩土工程学报》
北大核心
2025年第9期1977-1986,共10页
Chinese Journal of Geotechnical Engineering
基金
镇江市科技计划项目(基础研究专项)(JC2024019)
国家自然科学基金项目(51978317)
江苏省自然科学基金青年基金项目(BK20200996)。
关键词
加载频率
剪应变
孔压比
循环次数
剪切模量
模量衰退
loading frequency
shear strain
pore pressure ratio
number of cycles
shear modulus
modulus decline
