金沙考古遗址公园绿地雨水排蓄一体化改造研究

The Green Space Renewal with the Rainwater Drainage and Storage Integrated System in Jinsha Archaeological Ruins Park

考古遗址公园建设具有特殊性,为了保护地下遗址,往往大量回填土方,一般不设计人工水体。但这种建设方式造成排水困难,对地处降雨量大的金沙考古遗址而言,问题尤为严重,加重了遗址保护压力。为此,将古代及现代城市雨洪处理理念应用于金沙遗址公园绿地改造,通过排蓄一体的思路,提高绿地渗水率,形成自然河道和沟渠等构成的自然排水系统。具体技术措施包括:调整场地竖向规划,整合排水沟,增加蓄水、截留设施,实现雨水排蓄功能一体化;局部换填土与埋设盲沟相结合,提高土地渗水率;自然河道、排水沟渠沿岸配置莎草、鸢尾、巴茅、芦苇等亲水植物,营造生态水景;雨水沟栽植混合草,形成植草沟,降低径流系数。工程实施结果显示:"高挖低填"方式平衡了场地土方,优化了雨水沟坡度,消除了场地积水,减少了植物涝害死亡;排蓄一体让场地因水成景,蓄水用于绿地浇灌,降低了养护成本;植物配置减少了雨水对河道、沟渠的冲刷力,有利于岸线保护。

In order to protect the underground ruins, the construction method of archaeological park is often special, such as earthwork backfill, and no artificial large bodies of water. However, this way may bring trouble to the rainwater treatment after the park is built, especially like Jinsha Archaeological Park in Chengdu which is a rainy city. The conception of both the ancient and recent city flood control could provide new perspectives to solve the dilemma of Jinsha Archaeological Park, such as establishing the system with integrated functions of drainage and storage of water, which contains enhancing the rainwater permeability and constructing the ecological waterscape. In view of the enlightenment, a retrofit implementation plan is developed based on real situation: Firstly, the integrated water drainage and storage system was realized by re-arranging the venue orientation, combining separate ditches and retention facilities. Secondly, 2 options of replacing the soil and laying the blind ditch to increase soil infiltration rate are combined. Additionally, along the natural rivers and drainage ditches the sedge, iris, pampas grass, phragmites, and other hydrophilic plants are planted to create ecological waterscape. The artificial drainage ditch bottom is planted with mixed grass, to form grass ditch and reduce runoff coefficient. It is manifested that the transformation of the green space in Jinsha Park was effective. The effort is composed of such aspects as that the waterlogging in green space was disposed, and the retained rainwater decreased city water supply pressure. No plant would die after rainy season and the embankment of river were protected by diminishing the speed of rainwater.