WSGRI Engineering and Surveying Incorporation Limited
School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology
College of Civil Engineering, Taiyuan University of Technology

【目的】为了实现固废的资源化利用,采用膨润土改良尾矿砂,探究了压实尾矿砂-膨润土混合料作为填埋场覆盖系统防渗层材料的可行性。【方法】使用标准轻型击实试验确定了不同膨润土掺量下尾矿砂-膨润土混合料的最优含水率和最大干密度,通过固结渗透试验测试了不同膨润土掺量下尾矿砂-膨润土混合料的饱和渗透系数,通过压汞试验(MIP)和电镜扫描试验(SEM)分析了试样的微观孔隙特征,最后通过数值模拟研究了压实尾矿砂-膨润土混合料在覆盖系统中的服役性能。【结果】结果表明:随着膨润土掺量的增加,尾矿砂-膨润土混合料的最大干密度先增大后降低,在10%掺量下达到最大的1.94g/cm3,其渗透系数随着膨润土掺量的增加而降低,在膨润土掺量达到10%时,其ks=5.61×10-10m/s,满足防渗层渗透性要求(即ks≤10-9m/s),此时,10cm厚度的防渗层即可满足年渗漏量低于30mm/年的规范要求,同时设置一定的坡度和侧向导排作用可有效降低覆盖系统的渗漏量。

【Purposes】 To achieve the reuse of solid waste, the feasibility of using compacted tailings-bentonite material as an impermeable material for landfill cover system is explored in this study. The maximum dry density values of tailings-bentonite mixtures with varying bentonite contents are determined through compaction tests. 【Methods】 Saturated permeability coefficients of the tailings-bentonite mixtures were measured by using a consolidation permeameter. Addi- tionally, the pore characteristics of the samples were analyzed through mercury intrusion poro- simetry and scanning electron microscopy tests. Finally, the service performance of compacted tailings-bentonite mixture in cover systems was investigated by using numerical simulations. 【Findings】 The results reveal that the maximum dry density of the tailings-bentonite mixture first increases and then decreases with increasing bentonite content, reaching the maximum of 1.94 g/cm at 10% bentonite content. The permeability coefficient of the compacted tailings-bentonite mixture decreases with the increase of bentonite content. A bentonite content of 10% or higher satisfies the permeability requirement for the impermeable layer, i.e., k =5.61×10 m/s, ≤ m/s; in this case, an impermeable layer with a thickness of cm meets the requirement that annual percolation ≤30 mm. Additionally, setting a certain slope to facilitate lateral drain- age can effectively reduce the percolation through landfill cover system.

李梦云,丁洪元,李超越,等.压实尾矿砂-膨润土混合料在填埋场覆盖系统中的防渗性能研究[J].太原理工大学学报,2024,55(5):857-864.

LI Mengyun,DING Hongyuan,LI Chaoyue,et al.Study on the anti-seepage performance of compacted tailing sand-bentonite mixture in landfill cover system[J].Journal of Taiyuan University of Technology,2024,55(5):857-864.