明流冲刷与渗流潜蚀共同作用下土工袋固坡模式及应用研究

To explore the feasibility of using geotextile sandbag structure to revetment stability against sliding and to purificate drainage water reuse for agricultural irrigating based on geotextile containers technique that possessed the avdantages of protecting, draining and filtering and the characteristics of convenient construction and low cost. The agricultural drainage channels where locate northern irrigation district with serious salinization in Ningxia will be as the typical of study subject and the problems that ditch slope collapse frequently and water resources deficient for agricultural irrigation due to the distribution of drift sand formation underground and in any case the alternating cycles of wetting-drying and freezing-thawing will be presented by using the method of combining the theoretical with experimental research main focus on the soilbag in the material, size, structure and construction technique under overland erosion, seepage boil and purifed reuse water in consideration of the local natural conditions, social and economic development.The branches and lateral ditches will be essential study objective in this research project. Based on those results, optimize the laid out of the drainage ditch composition and design the integration system of irrigation and drainage according to the requirements of construct ecological water-saving irrigated area which water resource balance will be calculated in order to achieve the goal of reuse of ditch water for the shortage of irrigation water resource. The research results that will be suggested the stability against sliding and the purification method for the reuse of water to the ditch of agricultural drain engineering will not only be the base and guarantee of high standards of construction of prime farmland but also the fundamental way to mitigate irrigation water shortage problem, and to provide the technology support for the construction of ecological water-saving irrigated area and the sustained development of modern agriculture in the arid and semi-arid regions of north-western in China.

基于宁夏引黄灌区特定的自然条件和社会经济发展状况，以银北次生盐碱化较严重的干、支、斗级农业排水沟道为研究对象，针对排水沟道受流砂层以及干湿与冻融交替循环作用的影响，面临沟坡坍塌严重与灌溉水资源短缺的双重困境，借助土工合成新材料具有的防护、排水、过滤以及施工方便、造价低的优势，采用理论与试验相结合的研究方法，探索土工护坡袋新技术用于农田排水沟道的固坡防塌与排水过滤的可行性。重点研究符合农业排水实际要求，兼顾明流冲刷、渗流潜蚀与沟水回用过滤效果的护坡袋的袋材选择、袋体尺寸、铺筑结构及水质净化模式。在此基础上，为缓解当地日益突出的灌溉水资源供需矛盾，根据生态型节水灌区建设要求，提出基于护坡袋技术的灌区灌排一体化设计方案。排水沟道固坡防塌治理与沟水过滤净化既是建设高标准农田的基础与保障，也是实现灌排水循环利用的前提条件。预期研究成果将为西北干旱缺水地区农田基本建设和现代灌溉农业的发展提供技术支撑。

农田排水沟道滑塌与灌溉水资源短缺是制约宁夏引黄灌区高标准农田基本建设的瓶颈。选择宁夏引黄灌区青铜峡叶盛镇和邵岗镇农业综合开发项目区农田排水沟道为研究对象，研究了土工袋装技术砌护农田排水沟道边坡、过滤净化经土工袋渗入农田排水沟道的地下水质等科学问题。课题组通过实地调研、选点，确定了项目研究的试验区域，进行了土工袋砌护农田排水沟道的相关基础试验研究，包括抗拉、抗压、抗剪试验；不同水力梯度下的淤堵试验、不同砌护结构的渗透试验；不同袋材的过滤净化水质试验等室内试验工作。在此基础上，制定了土工袋砌护农田排水沟道的设计与施工方案，实地修建了土工袋砌护排水沟道的试验示范段，并且在试验区内浆砌石、格宾、草土柳桩和土工袋装技术等护坡方式砌护的农田排水沟道上布置了原位监测断面，观测不同沟道砌护模式的固坡效果。与此同时，针对农田排水沟道承泄地下水的功能以及宁夏引黄灌区普遍存在流砂地层的特殊情况，通过理论分析和数值模拟计算，重点研究了渗流条件下农田排水沟道底部存在流砂地层时土工袋砌护结构固坡效果和防滑塌治理措施。取得以下重要结果：①室内试验显示，不同位置土层与两种土工织物的摩擦系数均随着含水率增加而降低，土工袋湿润状态下的抗压能力较好，允许变形量也较大；各种土工袋砌护体结构的水平方向渗透系数大于垂直方向，错缝搭接土工袋砌护结构的渗透系数明显小于齐缝搭接方式，袋体尺寸越小，砌护体结构的渗透系数越大；土工袋装技术对通过袋体的渗滤水流的水质有一定净化效果。②原位监测数据表明，与传统草土柳桩护坡相比，土工袋装技术在固坡效果、施工便捷、工程造价等方面具有较大优势。③以试验区沟道为案例的固坡效果的理论分析与数值模拟计算表明，课题组研究制定的渗流条件下抵御沟底流砂地层渗透变形的农田排水沟道固坡设计方案是行之有效的。④提出了以小型光伏发电为动力、田间暗管排水与明沟排水相结合、灌溉与排水一体化设计的农田排水循环利用设计思路。