黄土饱和度与B值关系试验研究

Relationship between saturation degree and B value for loess

黄土由于结构不同于一般岩土体,三轴试验的饱和阶段,利用抽气饱和极易导致黄土结构扰动而发生破坏。而试样饱和是三轴试验中的重要步骤之一,且饱和度直接影响后期黄土力学性质的准确性。为研究不引起黄土结构破坏的饱和方法,利用天水和兰州所取原状黄土试样,在GDS三轴仪上开展了8组共33个试样的三轴饱和试验,基于体变传感器实时监测试样在饱和中所产生的体积变化,结合精确控制器测得试样中滞水质量,进行饱和度计算。同时利用GDS三轴仪进行B值检测,如此反复获得黄土试样饱和度与B值关系曲线。分析了不同饱和方式对黄土饱和效果的影响,并对黄土饱和度与B值关系进行非线性拟合,获得其定量关系:饱和度和B值存在指数函数关系。

Loess is a special soil because of its large pore structure and vertical joints. The structure of loess is unique, so the structure of loess will be destroyed if the loess is vacuum saturated. The saturation of soil is one of the important steps in the triaxial test. It is known that the saturation degree of specimen closely correlates with the accuracy of the loess mechanical properties. Eight groups of loess samples from Lanzhou and Tianshui, Gansu province, China, were used in the triaxial tests of saturation by GDS triaxial apparatus. A total volume change sensor was used during the saturation of loess samples. Later the total volume change tested by the sensor and the quantity of water in the sample tested by the controller. The saturation degrees of loess samples were calculated by the parameters of loess. After that, the B value would be collected by the computer at the same time. The relationship between the saturation degree and the B value was obtained at the same time. The influence of different methods of saturation on the loess was discussed. The nonlinear fitting on the saturation degree and B value was also conducted so that an empirical formula with exponential form was produced.