考虑冻融影响的FMLSS动力特性试验

Test of FMLSS dynamic characteristics subjected to freezing and thawing

为考察冻融因素对河道淤泥气泡混合土(FMLSS)动力特性的影响,通过试验研究了不同冻融条件下FMLSS动力特性的变化及其规律。研究结果表明,FMLSS的动应力-应变、动弹性模量-动应变之间符合双曲线关系;在一定的动应力水平下,动应变随冻融循环次数增大而增大;在一定的动应变条件下,动弹性模量随冻融循环次数增大而减小。经历一定次数的冻融循环作用后,在同样的动应力水平下,FMLSS动应变随原料土含水率、气泡掺入量的增加而增大,随水泥掺入量的增大而减小;在一定的动应变条件下,动弹性模量随原料土含水率、气泡掺入量增大而减小,随水泥掺入量增大而增大。原料土含水率与水泥掺入量是影响受冻融作用后FMLSS动力特性的主要因素。根据损伤力学基本理论,用相对动弹性模量表征了FMLSS经冻融循环后的动模量损伤度,建立了FMLSS冻融损伤的数学模型。

In order to investigate the effects of the freeze-thaw on the dynamic characteristics of the foamed mixture lightweight soil using river sludge (FMLSS), the variation and regularity of the FMLSS dynamic characteristics under different freezing and thawing conditions were investigated using tests. The results show that the fitting dynamic stress-strain and dynamic elastic modulus-strain curve of the FMLSS agree with the hyperbolic type;the dynamic strain of the FMLSS decreases with the increase of freeze-thaw cycles under a certain dynamic stress level;the dynamic elastic modulus decreases with the increase of freeze-thaw cycles under a constant dynamic strain. After a certain number of freeze-thaw cycles, the dynamic strain of FMLSS increases with the increase of original soil's water content or air foam content, and decreases with the increase of cement content at the same dynamic stress level;the dynamic elastic modulus of the FMLSS decrease with the increase of original soil's water content or air foam content, and increases with the increase of cement content under a certain dynamic strain condition. Original soil's water content and cement content are the main factors influencing the freeze-thaw spoilt of FMLSS. According to the basic theory of damage mechanics, the damage degree of dynamic modulus of FMLSS after freeze-thaw cycles is characterized by the relative dynamic modulus of elasticity, and the mathematical model of freeze-thaw damage of FMLSS is established.