| 废弃泥浆底部真空?上部堆载预压模型试验研究 |
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| 引用本文： | 詹良通,张斌,郭晓刚,江文豪.废弃泥浆底部真空?上部堆载预压模型试验研究[J].岩土力学,2020,41(10):3245-3254. |
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| 作者姓名： | 詹良通 张斌 郭晓刚 江文豪 |
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| 作者单位： | 1. 浙江大学 软弱土与环境土工教育部重点试验室，浙江 杭州 310058；2. 浙江大学 岩土工程研究所，浙江 杭州 310058 |
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| 基金项目： | 浙江省重点研发计划项目（No. 2019C03107） |
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| 摘 要： | 针对工程泥浆回填废弃矿坑处置的安全问题，开展底部真空和上部堆载预压处理废弃工程泥浆的模型试验，探讨该技术在废弃矿坑回填处置工程应用的可行性。试验结果表明，底部真空和上部堆载预压使得泥浆含水率显著降低及泥土的强度明显提高，处理一个月后，含水率从初始450%降低至95%～105%，体积减量达到73.4%；不排水强度由初始为0的状态提高至9.8～13.4 kPa。在初始的静置阶段，泥浆颗粒沉积存在重力分异现象，粗颗粒在底部沉积有助于缓解真空预压过程中淤堵问题。底部真空作用下，泥浆中孔隙水渗流方向并非完全一维向下，在径向存在水力梯度。处理后泥土压缩性与软土相近，渗透性优于软土。基于试验结果和大应变固结理论，考虑泥浆的自重固结以及压缩性与渗透性的非线性变化，利用有限差分法分析了单次回填厚度对泥浆层固结时间和减量效果的影响，提出了现场实施的工艺参数建议。
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| 关 键 词： | 废弃工程泥浆 底部真空预压 模型试验 固结 泥浆减量 |
| 收稿时间： | 2020-01-10 |
| 修稿时间： | 2020-06-11 |
Physical modeling study on treatment of waste slurry with vacuum preloading at bottom combined with upper surcharge loading |
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| ZHAN Liang-tong,ZHANG Bin,GUO Xiao-gang,JIANG Wen-hao.Physical modeling study on treatment of waste slurry with vacuum preloading at bottom combined with upper surcharge loading[J].Rock and Soil Mechanics,2020,41(10):3245-3254. |
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| Authors: | ZHAN Liang-tong ZHANG Bin GUO Xiao-gang JIANG Wen-hao |
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| Institution: | 1. Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education, Zhejiang University, Hangzhou, Zhejiang 310058, China;
2. Institute of Geotechnical Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China |
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| Abstract: | To solve the safety problem of using waste slurry to backfill discarded open pit mine, the treatment method of vacuum preloading at bottom combined with upper surcharge loading is implemented in the model test. The feasibility of using this method in the backfilling of discarded open pit mine is discussed. The test results show that the proposed method can significantly reduce the water content of the slurry and increase the shear strength of the soil. The water content of the slurry reduces from 450% to 95%–105%, and the reduction of volume reaches 73.4%. The undrained shear strength increases from zero to 9.8–13.4 kPa. In the initial self-weight consolidation stage, there is gravitational separation in the deposition of particles, and the deposition of coarse particles at the bottom is helpful to alleviate the clogging problem of vacuum preloading. During the stage of vacuum preloading, seepage direction of pore water in the slurry is not completely one-dimensional downward, and there is a hydraulic gradient in the radial direction. After the treatment, the compressibility of the soil is close to that of soft clay, while the permeability is greater than that of soft clay. Based on the experimental results and the large-strain consolidation theory, the effects of slurry thickness of a single disposal cycle on volume reduction and treatment time are analyzed using the finite difference method with consideration of the self-weight, nonlinear change of compressibility and permeability of the slurry. The process parameters for operation in site are recommended based on the results of numerical analysis. |
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| Keywords: | construction waste slurry vacuum preloading at bottom model test consolidation volume reduction of slurry |
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