阿勒山露天煤矿边坡层间薄层滑带土蠕变特性研究

Study on Creep Characteristics of Interlayer Thin Layer Soil of Slope in Aleshan Open Pit Coal Mine

以阿勒山露天煤矿蠕变失稳边坡为例,采用室内三轴剪切试验,获取滑带土试样在不同围压和应力水平下的应变规律,并进一步采用等时曲线法确定滑带土长期强度。研究表明,层间薄层滑带土具有典型的蠕变特征,蠕变阶段可分为衰减蠕变和稳定蠕变2个变形过程;滑带土绝对蠕变量和稳定蠕变阶段的变形速率均与轴向应力值呈正相关,而衰减蠕变阶段的持续时间随着剪应力水平增加基本呈线性增加。滑带土长期强度小于相同条件下的瞬时强度,与常规强度参数比较,其长期黏聚力C值和长期摩擦角准值分别下降24.8%和22.4%。

In this paper, taking the creep instability slope of Aleshan Opencast Coal Mine as an example, the triaxial shear test was carried out in laboratory to obtain the strain laws of the sliding belt soil samples under different confining pressures and stresses, and the isochronous curve method was further used to determine the long-term strength of the sliding belt soil. The study shows that the interlayer thin strip soil has typical creep characteristics, and the creep stage can be divided into two deformation processes;the attenuated creep and the stable creep. The absolute creep and the deformation rate of the stable creep stage are all positively correlated with the axial stress value, while the duration of the creep stage increases with the shear stress level. There is a linear increase. The long-term strength of the sliding zone soil is less than that of the same condition. Compared with the conventional strength parameters, the long-term cohesive C value and the long-term friction angle of the soil decreased by 24.8%and 22.4% respectively.