【摘要】 对岷县地震台、庆阳黄土塬2～12m深度土层的粉土、粉质黏土样品,利用室内动三轴试验和扫描电镜试验,测定阻尼比和微观结构特征,研究了粉土、粉质黏土的阻尼比随深度的变化及应力应变关系,采用灰色关联度方法,分析了黄土竖向(沉积方向)和横向(垂直于沉积方向)的微观结构参数对阻尼比影响的主次关系及其权重。研究结果表明:小应变下,粉土和粉质黏土阻尼比随着深度的增加而减小;粉土和粉质黏土的微观参数与阻尼比有一定的关联性,粉土竖向的微观参数对阻尼比的影响较为敏感;粉质黏土横向的微观参数对阻尼比的影响更加敏感;影响权重方面,粉质黏土的平均形状系数影响权重最大,对阻尼比的影响最大;粉土的平均形状系数、分形维数和概率熵影响权重最大,对阻尼比影响最敏感。平均面积无论在关联度还是影响权重方面对阻尼比影响最小,该结论粉土与粉质黏土保持一致。更多还原

【Abstract】 Taking silt and silty clay samples from Minxian Seismic Station and Qingyang Loess Plateau at depth of 2-12 m, the damping ratio and microstructure characteristics of silt and silty clay were measured by dynamic triaxial and scanning electron microscopy tests in laboratory. The relationship between the damping ratio of silt and silty clay with depth and stress-strain was studied.By means of grey relational degree method, the primary and secondary relations and weights of the influence of the micro-structural parameters of loess vertical(sedimentary) and transverse(vertical to sedimentary) on the damping ratio are analyzed. The results show that the damping ratio of silt and silty clay decreases with the increase of depth under small strain; The microscopic parameters of silty soil and silty clay have a certain correlation with damping ratio.The lateral Micro-Parameters of silty clay are more sensitive to the influence of damping ratio; The vertical Micro-Parameters are more sensitive to the influence of damping ratio; In terms of influence weight, the average shape coefficient of silty clay has the greatest influence on weight and damping ratio.The average shape coefficient, fractal dimension and probability entropy have the greatest influence weight, and are most sensitive to damping ratio. The average area has the smallest influence weight and the smallest influence on the damping ratio. This conclusion is consistent with that of silty clay.更多还原