| 基于可控性生态减渗目标的河床底质重构技术研究 |
| Research on Riverbed Sediment Reconstruction Technology Based on Controllable Ecological Seepage Reduction Targets |
| 投稿时间：2021-04-16 修订日期：2021-09-07 |
| DOI：10.15928/j.1674-3075.202104160113 |
| 中文关键词:生态补水 减渗措施 渗透系数 渗流模拟 河床垂向连通性 |
| 英文关键词:ecological water supplement seepage reduction permeability coefficient seepage simulation vertical connectivity of riverbed |
| 基金项目:国家水体污染与治理科技重大专项( 2018ZX07105-002)；水利部公益性行业科研专项(201501030) |
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| 中文摘要: |
| 位于地下水超采区且具有景观要求的河流，需同时具备维持生态水位和渗透补给地下水的功能，研究可调控减渗效果的河床底质重构技术对维持河床垂向连通性具有重要意义。以华北平原常见河床底质和膨润土为主要材料配比得到重构底质，通过变水头渗透试验与模型入渗试验探究了重构底质减渗特性，根据不同河流条件提出不同的配比及结构方案，利用GeoStudio SEEP/W软件计算模拟了不同方案的渗流及渗流量减少状况。结果表明，改变膨润土类型和掺量可调节底质的减渗效果，使其渗透系数达到小于1×10-6 cm/s和小于1×10-7 cm/s目标水平；纳基膨润土掺量为15%的重构底质在1 m水头渗透作用下，浸润锋经39 d运移15 cm，56 d内累计入渗量为11.1 cm，减渗效果较好；模拟结果表明，3种减渗方案具备不同的减渗效果，典型断面河流水位在0.3~2.0 m时，3种方案河流渗流损失量可降低55.8%~68.8%、91.5%~94.3%和94.8%~96.5%；方案1适用于减渗需求低、地下水回补要求高的河流，方案3适用于蓄水减渗需求高或水位较高的河流，方案2适用范围最广。研究结果可为华北平原河流生态补水及减渗修复工作提供参考和依据。 |
| 英文摘要: |
| Rivers located in groundwater overexploitation areas provide the functions of maintaining ecological water levels and supplying groundwater by infiltration. Thus, it is important to study riverbed substrate reconstruction technology to maintain the vertical connectivity of the riverbed by controlling seepage. In this study, we obtained the materials to reconstruct the riverbed sediment by mixing riverbed sediment from the North China Plain with various types of bentonite in different ratios. The infiltration characteristics of the reconstituted substrate were then explored using variable water head infiltration tests and model infiltration tests. Next, we proposed different seepage reduction ratios and developed three structural schemes (Scheme 1: 100mm seepage reduction layer with 9% sodium bentonite; Scheme 2: 150 mm seepage reduction layer with 15% sodium bentonite; Scheme 3: 200mm seepage reduction layer with 18% sodium bentonite) based on river conditions. Finally, GeoStudio SEEP/W software was used to simulate the seepage conditions and the seepage reduction effects of the three schemes were analyzed. Results show that permeability coefficient reduction by the composite sediment can be controlled by changing the type and content of bentonite, and two target permeability coefficients (< 1×10-6 cm/s and < 1×10-7 cm/s) were achieved. When the content of sodium bentonite in the composite soil was 15% and the infiltration head was 1 m, the infiltration front moved 15 cm in 39 days and the cumulative infiltration water volume in 56 days was 11.1 cm. The composite sediment was better at reducing seepage and simulation results indicate that the three schemes all effectively reduced the seepage flow. When the river water level rose from 0.3m to 2m, seepage loss was reduced by 55.8%-68.8% in Scheme 1, 91.5%-94.3% in Scheme 2, and 94.8%-96.5% in Scheme 3. Scheme 1 is suitable for rivers with low infiltration requirements and high groundwater recharge requirements, Scheme 3 is suitable for rivers with high infiltration requirements and high water levels, and Scheme 2 has the widest scope of application. Our results provide reference and basis for ecological water replenishment and infiltration reduction restoration work in the North China Plain. |
| 郑 亨,陈 卓,魏 俊,张 晶,赵进勇,王 琦,黄森军.2022.基于可控性生态减渗目标的河床底质重构技术研究[J].水生态学杂志,43(6):11-17. |
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