软岩土石混合体的击实特性与细观机理研究

Investigation on compaction characteristics and meso-mechanism of soil-rock mixture with soft rock blocks

以富宁换流站地基工程为背景,采用室内大型击实试验与数值模拟相结合的方法,探讨不同块石质量分数及不同块石形状的软岩土石混合体的击实特性及其细观机理.结果表明,软岩土石混合体的击实过程可以分为初始压密阶段、快速压密阶段和稳定阶段,且块石的破碎主要发生在初始压密阶段;随着块石质量分数的增加,软岩土石混合体的最大干密度先增大后减小,当块石质量分数为60%时达到最大值;击实后软岩土石混合体内部接触力分布服从接触力分布概率密度函数,且随着块石质量分数的增加,高于平均值的接触力的概率密度增大.块石的形状因子越大,块石的破碎率越高,击实后软岩土石混合体的最大干密度随块石的形状因子的增大先增大后减小.

Based on the foundation engineering of Funing converter station,the compaction characteristics and mesomechanism of soil-rock mixture with different stone mass fractions and different stone shapes were investigated by means of the compaction test and numerical simulation.Results show that the compaction process of soil rock mixture with soft rock blocks can be divided into initial compaction stage,rapid compaction stage and stable stage;the crushing of the stone mainly occurs in the initial compaction stage.With the increasing of stone mass fraction,the maximum dry density of soil rock mixture with soft rock blocks first increases and then decreases,and the optimum stone mass fraction is 60%.The contact force distribution in compacted soil-rock mixture obeys the probability density function of contact force,and the probability density of the contact force above the average contact force increases with the increase of stone mass fraction.The larger the shape factor of the rock block is,the higher the crushing rate of the stone is;after the compaction,the maximum dry density of soil rock mixture with soft rock blocks first increases and then decreases with the increasing of the shape factor of rock blocks.