改进暗管排水技术淤堵防护措施试验研究

基于室内土柱试验,依据太沙基准则,考虑2种反滤体铺设方式、2种土工布类型以及3种土工布铺设位置,模拟改进暗管排水条件下反滤体或土工布的单一防护措施以及反滤体与土工布结合的组合防护措施下排水流量的衰减过程,得到不同方案的土工布淤堵量及土壤流失量,提出改进暗管排水条件下反滤体及土工布的合理布局。研究结果表明,依据太沙基准则选择改进暗管排水的砂砾石规格是合理可行的;仅在暗管周围铺设土工布的分层和混合反滤体方案对防护土工布淤堵和土壤流失均有较好效果;综合考虑流量衰减过程、土工布淤堵量和土壤流失量,确保改进暗管排水的长期稳定运行,应优先考虑分层反滤体结合暗管周围铺设合理土工布的方案。

Experimental Study of Clogging Defense Measures for Improved Subsurface Drainage

Clogging is one of the main factors for long-term stable operation of subsurface drainage systems. It also should be paid attention during the application and popularization of subsurface drainage system. The main issues of applying improved subsurface drainage are choosing specifications for filter, preventing clogging, lowering the attenuation of discharge and reducing soil losses. Based on soil column experiment, two filter paving patterns, two kinds of geotextile and three laying locations of the geotextile were considered, the attenuation of discharge process, mass of geotextile clogging and mass of soil losses were simulated under single defense measure of filter or geotextile, and defense measures of filter and geotextile were combined respectively, the reasonable distribution of filter and geotextile for improved subsurface drainage was proposed. The results indicated that Terzaghi critera was reasonable and feasible for choosing specifications of gravel filter and it had good effect on preventing the attenuation of discharge for layered filter and mixed filter. By setting geotextile around the pipe, both layered and mixed filters worked well on slowing down the attenuation of discharge and clogging and soil losses. Furthermore, from the comprehensive view of attenuation of discharge and clogging and soil losses, considering the long-term safe and stable operation of the improved subsurface drainage, priority should be given to the combined measure of layered filter and geotextile around the pipe.