动荷载下不同细粒含量粉土孔压发展模式研究

Pore Pressure Development Model of Silt With Different Fine Contents Under Dynamic Load

为研究动荷载作用下不同细粒含量粉土试样孔压发展模式,通过室内动三轴试验,基于传统分析法和能量分析法研究黏粒含量和粉粒含量对孔压发展模式的影响.结果表明:黏粒含量9%是粉土孔压累积规律发生改变的转折点,当黏粒含量小于该值时,孔压时程曲线呈现“增长-趋稳”规律;而黏粒含量高于该值时,孔压累积呈“增长-变缓-增长-趋稳”变化规律.黏粒含量或者粉粒含量越小,孔压时程曲线越陡峭,动应力-应变滞回圈分布越疏,孔压累积速度越快.通过非线性回归分析,建立了考虑细粒含量粉土孔压发展计算公式以及孔压-累积损耗能量归一化公式.

In order to study the pore water pressure development model of silt samples with different fine grain contents under dynamic load,the influence of clay content and silt content on the pore water pressure development model was studied by indoor dynamic triaxial test based on traditional analysis method and energy analysis method.The results show that the clay content of 9%is the turning point of the change of the accumulation law of pore water pressure in silt.When the clay content is less than this value,the time-history curve of pore water pressure shows the law of“increasing-stabilizing”.However,when the clay content is higher than this value,the pore water pressure accumulation shows the changing law of“increasing-slowing down-increasing-stabilizing”.The smaller the clay content or silt content,the steeper the time-history curve of pore pressure,the thinner the distribution of dynamic stress-strain hysteresis loop,and the faster the accumulation rate of pore pressure.Through nonlinear regression analysis,the calculation formula of pore water pressure development and the normalized formula of pore water pressure-cumulative loss energy considering fine grain content are established.