煤矸石回填土物理力学性能试验研究

Experimental study on physics and mechanics performances of coal refuse backfill soil

为了解煤矸石作回填土的掺砂量与强度之间的关系,找出具有工程实应用的配比,对不同配合比条件下的煤矸石回填土的物理性能(含水量、最大干密度、最佳含水量)和力学性能(粒径级配、压缩系数、黏聚力、内摩擦角)进行了试验研究,并根据试验数据构建线性回归预测模型对地基承载特征参数进行了预测。试验结果表明:煤矸石作回填土其不均匀系数为6.44,曲率系数为1.621,级配良好,有利于压实。3种配合比试验的压缩系数分别为0.31、0.29、0.26,属于高压缩性土。试验土样在黄土掺量不断增加后,剪应力、黏聚力和内摩擦角也随之增加,说明该土样的抗剪强度随着黄土掺量增加而增加,根据指标预测值计算得到地基承载特征值,符合建筑规范要求。

In order to find the relationship between the sand content of coal refuse backfill soil and the strength,a mixing ratio with the engineering application was determined. An experimental study was conducted on the physical performances( moisture content,max dry density,optimum moisture content) and the mechanics performances( particle size distribution,compression coefficient,cohesion and internal friction angle) of the coal refuse backfill soil under the different mixing ratio condition. Based on a linear regression prediction model established with the experiment data,a prediction was conducted on the foundation loading features and parameters. The experiment results showed that nonuniform coefficient of the coal refuse backfill soil was 6. 44,the curvature coefficient was 1. 621 and the graduation was good and was favorable to the compaction. The compression coefficient of three mixing ratio experiments was 0. 31,0. 29 and 0. 26 individually and was a high compressive soil. After the loess mixing value of the experiment soil sample continuously increased,the shear stress,cohesion and internal friction angle also would be increased and the shear strength of the soil sample would be increased with the loess mixing ratio increased. According to the index prediction value,the foundation loading feature value was calculated and obtained to meet the requirements of the constructional standards.