含水率和压实度对矿区回填土力学性质的影响

Affect of Water Content and Compaction Degree on Mechanical Characteristics of Backfill in Coal Mine

以某矿区填土为研究对象,采用直剪试验和压缩试验,对不同含水率及不同压实度条件下的土样进行抗剪强度和压缩指标的测定,并分析了因含水率和压实度的不同引起抗剪强度和压缩特性的变化规律。结果表明:当所选取的含水率均不大于最优含水率时,黏聚力随含水率变化不明显,但在高压实度下,存在1个含水率值,令填土的黏聚力达到峰值,而内摩擦角受含水率变化影响较小;黏聚力随压实度的增大而增大,且呈指数形式增长,内摩擦角随着压实度增大呈近似线性增长,且增长幅度不大;压缩系数随含水率的增大而增大,压实度对压缩系数的影响与含水率影响相反,呈递减趋势。

Taking the backfill in a mining area as research object, using direct-shear test and compression test, we measured shear strength and compression index of soil samples with different water content and compaction degree, and analyzed the variation laws of shear strength and compressive properties due to different water content and compaction. The experimental results show that the value of cohesion has no obvious change as water content increases when the water content was not greater than the optimal moisture content; but, under the high pressure degree, there is a water content value that makes the cohesion of soil reach the peak, and the friction angle has little change with the change of water content; the cohesion has an exponent increase with the increasing of dry density, but the friction angle increases linearly with the increasing of compaction degree; the compaction degree increases with the increasing of water content, and the effect of the compressibility on compaction degree is opposite to that of water content.