低水泥掺量对模袋充灌特性的影响试验

为提高施工效率和细尾砂利用率,将不同质量比的水泥掺入浓度40%的尾矿浆,开展模袋充灌试验,研究水泥掺量对模袋充灌特性的影响规律。结果表明:在细尾矿浆中掺加水泥作为固化剂,可提高模袋的透水性和保砂性;充灌时间和排浆密度随水泥掺量的增大而减少;单次充浆体积和单次排浆体积随充灌时间的延长呈指数递减;排浆集中在前2 h,以静水压力排浆为主,此后以固结尾砂自重挤压排浆为主;排水率、排水效率和保砂率随水泥掺量的增大而增大;排水效率和保砂率可分别作为评价模袋透水性和保砂性的指标,综合考虑施工效率、细尾砂利用率和施工成本,最佳水泥掺量确定为3%。

Experiments on grouting characteristics of geosynthetic tubes influenced by low cement content

In order to improve the construction efficiency and the utilization rate of fine grained tailings, cement of different mass ratios was mixed with fine tailing slurry of which the mass concentration was set to be 40%. Grouting test of geosynthetic tubes was carried out to explore the influence of cement content on the grouting characteristics of geosynthetic tubes. According to the experimental results, the addition of cement as curing agent in the fine tailings mortar can improve the water permeability and sand retention of the geosynthetic tubes. The grouting time and the density of mortar discharging decrease with the increase of the cement content. The quantity of single grouting and single discharge decreases exponentially with the increase of time. The discharge is concentrated in the first two hours, dominated by hydrostatic pressure, and after that, the discharge is dominated by consolidation extrusion due to the dead weight of the fine tailings. The drainage rate, drainage efficiency and sand retention rate increase with the increase of cement content. The drainage efficiency and sand retention rate can be selected as the indexes to evaluate the permeability and sand retention of geosynthetic tubes, and the optimal cement content is determined as 3% after comprehensive consideration of construction efficiency, utilization rate of fine tailings and construction cost.