Mechanical response of geomembrane seepage barrier in side slope of an evaporation pond
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摘要: 含防渗层的蒸发塘不仅可储存废液减免污染,还可通过蒸发结晶提取废液中的盐类,获取经济效益。在缺少黏土等天然防渗层的地区,土工膜等人工合成材料防渗层是控制蒸发塘所蓄废液外渗的关键,其物理力学性能与防渗效果紧密相关。在施工和运行过程中,柔性土工膜会与其赋存的岩土体等相对刚性的环境产生相互作用,从而影响土工膜的力学性能。鉴于此,以一位于寒区的蒸发塘为例,基以过程模拟的方法,研究了蒸发塘土工膜防渗层这一赋存于相对刚性环境中的柔性结构在施工、蓄水和塘水结冰条件下的力学响应。研究表明柔性土工膜与其赋存的相对刚性的地基层和保护层之间存在界面相对摩擦和同向变形协调两种作用,塘内蓄水、结冰等外界环境的作用可通过保护层间接作用于土工膜防渗层。锚固沟处土工膜易应力集中,锚固沟设计和施工时建议遵循“可拉动不拉断”。数值模拟中当土工膜防渗层的最大变形受到模拟方法的限制时,可利用应力判别运行状态。Abstract: The evaporation pond with seepage barrier can store waste liquid, limit pollution and extract solution through evaporation by sunlight. In the areas without natural barrier, such as clay, geomembrane is usually applied. So the physical and mechanical properties of geomembrane are essential to the seepage controlling. During construction and operation of evaporation ponds, soft geomembrane will interact with the surrounding relative rigid foundation and protection cover, and its performance is affected. Taken an evaporation pond sited in cold region as an example, the mechanical response of geomembrane to construction, impounding and expansion of ice is investigated. It is shown that two interactions exist between the geomembrane and the surrounding materials. One is interface friction and the other is coordinate deformation along the same direction. The effect of impounding and expansion can be applied to the geomembrane through protection cover. Stress concentration appeares at anchor trench, thus the geomembrane should be able to move in the anchor trench before breaking. If the simulated deformation is limited by the ways of modelling, stresses should be taken to determine the state of geomembrane.
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Keywords:
- evaporation pond /
- geomembrane /
- numerical modelling /
- waste liquid
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[1] 姜兴涛, 姜成旭. 利用蒸发塘处置煤化工浓盐水技术[J]. 化工进展, 2012(增刊1): 276-278. (JIANG Xing-tao, JIANG Cheng-xu. Use of evaporation ponds disposal of coal chemical industry concentrated brine technology[J]. Chemical Progress, 2012(S1): 276-278. (in Chinese)) [2] 姜海波, 侍克斌. 坝坡复合土工膜防渗体的抗滑稳定分析[J]. 水资源与水工程学报, 2010, 21(6): 15-18. (JIANG Hai-bo, SHI Ke-bin. Dam slope stability against sliding of the composite geomembrane impervious body analysis[J]. Journal of Water Resources and Water Engineering, 2010, 21(6): 15-18. (in Chinese)) [3] 邢玉玲. 膜土联合防渗堆石坝内部应力研究[D]. 南京: 河海大学, 2007. (XING Yu-ling. Membrane soil internal stress research joint antiseepage rockfill dam[D]. Nanjing: Hohai University, 2007. (in Chinese)) [4] 尚 层, 李玉建, 徐千军, 等. 复合土工膜不同锚固型式对膜应力变形的影响研究[J]. 中国农村水利水电, 2012(10): 72-75. (SHANG Ceng, LI Yu-jian, XU Qian-jun, et al. Compound geomembrane the influence of different deformation and stress of anchor type on membrane research[J]. China's Rural Water Conservancy and Hydropower, 2012(10): 72-75. (in Chinese)) [5] 岑威钧, 沈长松, 童建文. 深厚覆盖层上复合土工膜防渗堆石坝筑坝特性研究[J]. 岩土力学, 2009, 30(1): 175-180. (CEN Wei-jun, SHEN Chang-song, TONG Jian-wen. Composite geomembrane anti-seepage rockfill dam on thick moraine cover foundation characteristic research[J]. Rock and Soil Mechanics, 2009, 30(1): 175-180. (in Chinese)) [6] 高 登. 扩建垃圾填埋场中间衬垫变形与稳定性状及其工程控制措施[D]. 杭州: 浙江大学, 2009. (GAO Deng. The expansion of the landfill sites in the middle pad deformation and stability of stability of traits and its engineering control measures[D]. Hangzhou: Zhejiang University, 2009. (in Chinese)) [7] WU W, WANG X T F. Aschauer. Investigation on failure of a geosynthetic lined reservoir[J]. Geotextiles and Geo- membranes, 2008, 26: 363-370. [8] Itasca Consulting Group, Inc. FLAC 3D - Fast lagrangian analysis of continua in 3 dimensions, Ver. 3.0, User's Manual[M]. Minneapolis: Itasca, 2005.