动荷载作用下重塑黏质粉土的弹性变形研究

摘要

Cyclic triaxial tests on the Ningbo saturated remolded clayey silt were carried out to study the effects of drainage condition,confining pressure,dynamic stress and temperature on the dynamic characteristics of soil.An empirical formula considering the effect of confining pressure,for the relationship between the dynamic elastic modulus and elastic strain was built.In addition,two empirical formulas for calculating the dynamic elastic modulus and the elastic strain under different confining pressure and dynamic stress were also established.The results show that with the increase of the number of vibration times,the dynamic elastic modulus and elastic strain at first change rapidly up to their extreme points and then after the extreme points,the dynamic elastic modulus and elastic strain gradually recover and approach to their stable state.The higher the temperature,the greater the value of dynamic elastic modulus and the smaller the elastic strain (thermal hardening).The empirical formulas can be used to calculate the dynamic elastic modulus and the elastic strain of clayey silt after enduring long-term vibration load.%以宁波黏质粉土为对象,在不同排水、围压、动应力以及温度条件下,开展了一系列动三轴试验,研究了土体的弹性变形特性,建立了考虑围压影响的动弹性模量和弹性应变关系的经验公式,并给出了不同围压、动应力下动弹性模量和弹性应变计算公式.结果表明:随着振次的增加,动弹性模量(弹性应变)迅速减小(增大),并有较为明显的极值点,随后有一定的恢复,最终趋于稳定;温度越高,动弹性模量值越大,弹性应变越小,土体出现热硬化现象;建立的计算公式可用于长期动荷载作用后黏质粉土的动弹性模量和弹性应变计算.