关键词: 采砂坑, 格形开挖, 河床演变, 溯源冲刷

Abstract: Four gravel pits were excavated along the secondary channel by way of grid-type excavation at Deg an shallow patch in upper Changjiang river. After founded and validated the two dimensional mathematical model, the changes of the flow field with four representative flow quantities was calculated. The riverbed development of Degan river section was analyzed and the river regime of one hydrographic year was observed. Thus the conclusion could be reached that few changes would take place to river regime and backward erosion would hardly happen because of these gravel pits. The influence to wading constructs is very little. Partial collapse happens in a short range around gravel pits in flood. The sand peduncle above pipeline between two gravel pits isn't steady enough, so conservation measure is necessary .

Key words: gravel pit, grid-type excavation, riverbed development, backward erosion