【摘要】 在大量动三轴试验的基础上,对压实黄土的动力特性进行研究。试验结果表明:压实黄土的动应力-应变曲线在一定条件下近似为双曲线模型,并得到部分试样的模型参数取值。压实黄土动弹性模量随着动应变的增加而减小,逐渐趋于稳定,并且在不同干密度、不同含水率及不同围压状态下变化趋势基本相同。阻尼比受含水率、固结应力比、干密度及围压等因素的影响,综合反映为随动应变的增加而增加,取值为0.2～0.3,但离散性较强。振陷变形与干密度、含水率及荷载作用次数有着密切关系,干密度愈大,含水量越小,振动次数愈大;在同等的应力条件下,振陷变形愈小,并且存在一临界动应力。当动应力小于该值时,振陷变形较小,与动应力近似线性关系;当动应力大于该值时,振陷变形增加较快,呈现明显的非线性。更多还原

【Abstract】 Based on a lot of dynamic triaxial tests,some dynamic characteristics on roadbed compaction loess are studies. It is indicated that from test results,the relation between stress and strain can be fitted with hyperbolic model under certain conditions,and the values of model parameters are and tend to be stable gained on some soil samples. Dynamic modulus of compaction loess decreases with the increase of dynamic strain,the trend is basically similar under different dry densities,water contents and pressures. Damping ratio is affected by the moisture,consolidation stress ratio,confining pressure and dry density of the compacted loess which increases with the increase of dynamic strain generally;and its value is distributed in 0.2–0.3 with high discreteness. The value of vibration deformation has important relation with the dry density,moisture and load cyclic number. When the dry density increases,moisture decreases,and load cyclic number increases. It decreases slowly at the same stress conditions,and there is critical dynamic stress. When the dynamic stress is smaller than it,vibration deformation is small and can be fitted linearly with the dynamic stress,otherwise,it increases quickly and presents obvious non-linearity.更多还原