某排土场散体物料力学性质的试验

Test of the Mechanical Property of the Bulk Material of a Dump

排土场散体物料力学参数除受本身性质决定外,主要还受排土工艺和排土速度等参数影响。针对某排土场散体物料的砾石含量和尺寸影响因素,采用粗粒土大型三轴试验,配置多组不固结不排水试样,分析散体物料力学的性质。结果表明,散体物料的应力-应变曲线在几何形式上表现为近似双曲线型,在物理形式上表现为硬化型曲线;当应变量为15%对应的强度峰值时,散体物料的摩擦角随砾石含量和尺寸增大而增大,黏聚力随砾石含量和尺寸减小而增大,主要因为摩擦角受砾石"二次啃断"而表现为增加,黏聚力受土相对含量增加,胶结作用表现明显而增加。通过对散体物料在台阶上的自然滚落堆积规律进行试验研究,将较高的排土场台阶分为2层或3层,取不同的岩土强度参数进行稳定性计算是符合实际情况的。

The mechanical parameters of the bulk material of dump are not only determined by their own properties, but also affected by soil discharging process, soil discharging speed and other parameters. According to the gravel concentration and the influence factors of gravel size of a dump, large triaxial test method for coarse soil is adopted, multiple unconsolidated and undrained specimens are obtained, so as to analyze the mechanical property of bulk materials. The study results show that, stress-strain curve of bulk materials is approximately hyperbolic in geometric form, and it is shown as hardening curve in physical form; when the strain is 15% of the corresponding strength peak value, the friction angle of bulk material increases with the increasing of gravel contents and size, the cohesion increases with the increasing of gravel contents and size, the main reason is that the friction angle is increased by the ＂secondary gnawing＂ of gravel, the relative content of cohesion is increased, the cementation effect is obvious. The actual situation of the dump can be studied by the study process that based on the test of natural rolling and accumulation law of bulk material on steps, the upper steps of the dump are divided into two or three layers, so as to conduct stability computation by different geotechnical strength parameters.