冲击荷载下土体动力响应与加载速率效应研究  

Dynamic response and effect of loading rate of soil under impact loading

作　　者：刘勇健 傅杨攀[2] 赖明洋 李彰明 方昊圆[2] 谢治堃 LIU Yong-jian;FU Yang-pan;LAI Ming-yang;LI Zhang-ming;FANG Hao-yuan;XIE Zhi-kun(School of Civil Engineering,Guangzhou Institute of Science and Technology,Guangzhou,Guangdong 510040,China;School of Civil and Transportation Engineering,Guangdong University of Technology,Guangzhou,Guangdong 510006,China;Guangzhou Urban Planning&Design Survey Research Institute,Guangzhou,Guangdong 510060,China)

机构地区：[1]广州理工学院建筑工程学院,广东广州510540 [2]广东工业大学土木与交通工程学院,广东广州510006 [3]广州市城市规划勘测设计研究院,广东广州510060

出　　处：《岩土力学》2023年第9期2485-2494,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金项:(No.52078142);广东省自然科学基金项目(No.2021A1515011691,No.2022A151011047,No.2020A1515010811)。

摘　　要：为揭示土体在冲击荷载作用下的动态响应特征,运用自主研发的附加激发力式平板动力载荷试验系统(flat dynamic load test,简称FDLT试验)对广州大学城区内两种典型土体(砂土和黏土)进行了不同荷载大小和加载速率的FDLT试验,获取了土体在冲击荷载下的荷载-时程曲线、位移-时程曲线、荷载-位移曲线的3种关系曲线。建立了动态变形模量与加载速率的经验公式,对比分析了两种土体在冲击荷载作用下的加载速率效应。研究表明:(1)砂土的FDLT试验存在一个充电量临界值,在该充电量冲击试验过程中,加载速率对砂土的动态强度及变形有较大的影响,而对黏土在本次试验条件下未有明显影响。(2)加载速率对黏土与砂土的位移响应的相同之处在于,最大荷载和最大位移均随加载速率的增大而提高;不同之处在于,黏土达到位移峰值时间会随加载速率增大而延长,而砂土达到位移峰值时间随加载速率增大呈现先增加后减小的规律。(3)土体的动态变形模量与加载速率曲线呈对数变化关系。本研究成果可为土体动力特性研究、土的动静参数换算和工程设计提供依据。To study the dynamic response characteristics of soil under impact load,flat dynamic load tests(FDLT)with different load levels and loading rates were carried out on two typical soils(sand and clay)in Guangzhou University Town by using the self-developed additional excitation force-type FDLT system,obtaining three characteristic curves of load-time curve,displacement-time curve,and load-displacement curve,establishing the empirical formula of dynamic deformation modulus and loading rate,and comparing the effects of loading rate of the two soils under impact load.It shows that:(1)There is a threshold of charging voltage in the FDLT test of sand.During the impact test on this threshold,the loading rate has a great effect on the dynamic strength and deformation of sand,while it has no obvious effect on clay under the same conditions.(2)The same point of the loading rate on the displacement response of clay and sand is that the maximum load and maximum displacement of the two soils both increase with the increase of loading rate.The difference is that the time for clay to reach the peak displacement increases with the increase of loading rate while the time for sand to reach the peak displacement shows a pattern of increasing and then decreasing with the increase of loading rate.(3)The dynamic deformation modulus varies logarithmically with the loading rate.The results can provide a reference for soil dynamic characteristics study,dynamic and static parameter conversion and engineering design.

关 键 词：加载速率 平板动力载荷试验 冲击荷载 动态参数 

分 类 号：TU413.5[建筑科学—岩土工程]