摘要
为了建立黏性土动态回弹模量的一种室内快速测试方法,基于弹性应力波理论,通过分析冲击回波法的力学边界条件与测试机理,运用瞬态动力学显式有限元方法揭示了冲击回波测试工况下弹性应力波在黏性土内从冲击、传播到反射的全过程动力响应特征。同时考虑以土体的阻尼比和源检距作为影响因素,对冲击回波感知黏性土动态回弹模量的精度进行了敏感性分析,据此提出了测试技术参数的合理控制范围。然后,通过选取典型土样,室内制作了18组不同含水率与压实度的黏性土试件进行对比实测,发现在含水率一定的条件下,冲击回波测得的动模量与压实度成正比。在压实度一定的条件下,当黏土偏干时,冲击回波测得的动模量与含水率成正比,而当土体偏湿时,冲击回波测得的动模量与含水率成反比,据此建立了冲击回波测试动态回弹模量结果与干密度及含水率之间的多元回归关系式。最后,通过与室内杠杆压力仪和动三轴仪进行对比测试,发现冲击回波测试动态回弹模量结果与其他方法测试相应结果之间正相关,呈现良好的幂函数关系,且所有相关系数均大于0.9,并随着黏性土中小于0.075 mm的细粒组含量的增大,相关系数也逐渐增大,表明应用冲击回波法室内测定与评价黏性土等细粒土的压实质量及动力特性是合理、可行的。
In order to establish an indoor rapid test method for the dynamic resilience modulus of clay,based on the elastic stress wave theory,by analyzing the mechanical boundary conditions and test mechanism of the impact-echo method,the dynamic response characteristics of the elastic stress wave in the whole process from impact,propagation to reflection in clay under the condition of impact-echo test are revealed by explicit finite element method for transient dynamics.Meanwhile,considering the soil damping ratio and source inspection distance as the influencing factors,the sensitivity analysis for the accuracy of clay’s dynamic resilient modulus sensed by impact-echo is carried out,and the reasonable control range of testing technical parameters is put forward accordingly.Then,selecting typical soil samples,18 groups of clay samples with different moisture contents and compactnesses are made in laboratory.It is found that under the condition of certain moisture content,the dynamic modulus measured by impact-echo is directly proportional to the compactnesses.Under the condition of certain compactnesses,when the clay is dry,the dynamic modulus measured by impact-echo is directly proportional to the moisture content,while when the soil is wet,the dynamic modulus measured by impact-echo is inversely proportional to the moisture content.Accordingly,the multiple regression relationships of dynamic resilient modulus measured by impact-echo with dry density and moisture content are established.Finally,through the comparison of the indoor lever pressure test with dynamic triaxial test,it is found that(1)there is a positive correlation between the results of dynamic resilient modulus tested by impact-echo and the corresponding results of other test methods,which presents a good power function relationship,all the correlation coefficients are greater than 0.9,and the correlation coefficient also increases gradually with the increase of the content of fine particles less than 0.075 mm in clay,indicating that to indoor measure an
作者
杨博
高荣川
袁晨峰
邹泽渝
汤跃文
YANG Bo;GAO Rong-chuan;YUAN Chen-feng;ZOU Ze-yu;TANG Yue-wen(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;School of Earth Sciences,Zhejiang University,Hangzhou Zhejiang 310027,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2022年第4期41-50,107,共11页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(51708071)
国家重大科研仪器研制项目(51927814)
重庆市自然科学基金项目(cstc2018jcyjAX0640)
重庆市教育委员会科学技术研究项目(KJ1705133)。
关键词
道路工程
测试技术
冲击回波法
动态回弹模量
黏性土
瞬态动力学显式有限元方法
road engineering
testing technology
impact-echo method
dynamic resilient modulus
clay
explicit finite element method for transient dynamics
