红粘土动本构关系与动模量衰减模型  

Dynamic constitutive relation and dynamic modulus attenuation model of red clay

作　　者：刘晓红[1,2] 杨果林[1] 方薇[1] 

机构地区：[1]中南大学土建学院,长沙410075 [2]湖南理工学院土建系,岳阳414000

出　　处：《水文地质工程地质》2011年第3期66-72,共7页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金资助项目(50778180);铁道部科技研究开发计划项目(2005K002-B-2-1)

摘　　要：针对高速交通循环荷载下红粘土路堑基床的动力稳定性问题,基于大量室内动三轴试验,研究了不同试验条件下原状结构红粘土动本构关系及动模量衰减规律。试验成果表明:原状结构红粘土动本构关系仍可用R.L.Kondner双曲线模型描述;动模量随动应变的增大非线性减小,具有明显的应变软化特征。围压、固结比、含水比对红粘土动本构特征及动模量衰减规律均有明显影响。不考虑其它因素,随围压或固结比的增大,动本构曲线逐渐偏向应力轴,随含水比的增大,动本构曲线逐渐偏离应力轴。同等条件下,动模量随围压、固结比的增大而增大,随含水比的增大而减小。基于回归分析,给出了不同试验条件下原状结构红粘土双曲线模型参数、动模量衰减经验公式及其拟合参数。In view of the dynamic stability of red clay subgrade under high-speed traffic cyclic loading, the dynamic constructive relation and attenuation laws of dynamic modulus are studied through a series of cyclic triaxial tests on red clay in original structure. The test results show that the dynamic constitutive relation of red clay in original structure can be described with the hyperbolic curve model presented by R. L. Kondner, dynamic modulus of it reduces nonlinearly with the accretion of dynamic strain and has obvious characteristics of strain softening. The obvious effects on dynamic constitutive relation and attenuation laws of dynamic modulus are found from confining pressure, consolidation ratio and water content ratio. Without consideration of other factors, dynamic constitutive curves tend gradually to stress axis with the increase of confining pressure or consolidation ratio and deviate gradually from stress axis with the increase of water content ratio. Dynamic modulus increases with the increase of confining pressure and consolidation ratio and decreases with the increase of water content ratio under the same conditions. Based on regression analysis, the hyperbolic model parameters of red clay in original structure under different test conditions, the empiric formula on dynamic modulus attenuation and the fitting parameters are given.

关 键 词：原状结构红粘土 动本构关系 动模量 衰减模型 动三轴试验 

分 类 号：TU435[建筑科学—岩土工程]