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  

Study on the Anti-seepage Performance of Compacted Tailing Sand-Bentonite Mixture in Landfill Cover System

作　　者：李梦云 丁洪元 李超越 闵明 蒲诃夫[2,3] 董晓强 曹剑峰[2] LI Mengyun;DING Hongyuan;LI Chaoyue;MIN Ming;PU Hefu;DONG Xiaoqiang;CAO Jianfeng(WSGRI Engineering and Surveying Incorporation Limited,Wuhan 430080,China;School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;College of Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]中冶武勘工程技术有限公司,武汉430080 [2]华中科技大学土木与水利工程学院,武汉430074 [3]太原理工大学土木工程学院,太原030024

出　　处：《太原理工大学学报》2024年第5期857-864,共8页Journal of Taiyuan University of Technology

基　　金：国家重点研发计划项目(2019YFC1806000);国家自然科学基金项目(52078235)。

摘　　要：【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1.94 g/cm^(3),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k_(s)=5.61×10^(-10) m/s,满足防渗层渗透性要求(即k_(s)≤10^(-9) m/s),此时,10 cm厚度的防渗层即可满足年渗漏量低于30 mm/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.Additionally,the pore characteristics of the samples were analyzed through mercury intrusion porosimetry 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~3 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_s=5.61×10~(-10) m/s,≤10~(-9) m/s;in this case,an impermeable layer with a thickness of 10 cm meets the requirement that annual percolation ≤30 mm.Additionally,setting a certain slope to facilitate lateral drainage can effectively reduce the percolation through landfill cover system.

关 键 词：覆盖系统 尾矿砂 膨润土 渗透性 渗漏量 

分 类 号：TU443[建筑科学—岩土工程]