涝渍地暗管排水示范工程建设有关问题研究

RESEARCH UPON THE PROBLEMS CONCERNED WITH THE DEMONSTRATION OF CONDUIT PROJECT CONSTRUCTION FOR WATERLOGGED LAND DRAINAGE

结合中日专项技术合作四湖项目的具体实践,指出了暗管工程规划中排水调查的内容和重点,就如何评判暗管排水的必要性和确定暗管设计排水量进行了探讨,分析了暗管排水与规划单元排灌系统的关系。排水调查是农田基本建设实施过程中不可缺少的一个环节,就涝渍地治理改造而言,调查的重点是要弄清排水不良的原因和取得解决问题的基础资料。为了制定符合实际的农田排水规划实施方案,可从土壤类型、土壤承载力、降雨后地表积水状况、土壤透水性和地下水位等对规划单元内的农田是否需要暗管排水作出判断。对水田而言,在田面水排除后,依靠暗管要排除地表残留水和过剩的土壤重力水,据此决定暗管设计排水量。对于旱田,渗入土壤中以重力水存在的过剩水需要通过暗管排除,据此决定暗管设计排水量。暗管工程适于江河中下游地势低洼、排水不良的农田,当明排不能有效地降低地下水位满足作物生长时,有必要采取暗管排水。

In combination of the concrete practice of the fourlake project which belongs to the special technology cooperation project between China and Japan,the contents and emphasis of drainage investigation were pointed out in the conduit project planning. The necessity of the conduit drainage was discussed. The relationship was analyzed between conduit drainage and drainageirrigation system in the program. Drainage investigation is an inevitable link in the process of implementing basic farmland construction. In view of waterlogged land control, the focal point for the investigation is to understand the reason of the poor drainage and to obtain the related information for a given problem. In order to make out an implemental schedule for farmland drainage, whether drainage by conduit is essential for farmland is judged by soil type, strength of soil bearing load, water deposition in land surface after raining, soil permeability and groundwater table etc. For paddy filed, after elimination of water in field surface it is essential for the rest of water in field surface and surplus gravity water in soil to be eliminated by buried pipe, and conduit design discharge for drainage depend upon them. For upland, rainfall infiltrating into soil and existing in gravity water status is named as surplus water in soil, and need to be eliminated by conduit. Conduit project is suitable for those fields with low relief and poor drainage in middle and low reaches of rivers. Drainage by conduit is essential to adopt when open canal can't lower down effectively groundwater to meet crop growth.