南水北调工程高潜水强透水地基渠道施工期渗流及降排水研究

Study on Seepage and Dewatering of Foundation with High Phreatic Water and Seepage during Canal Construction,South- to- North Water Diversion Project

采用三维有限元方法对南水北调工程温博段渠道开挖过程、排水渗流及边坡渗透稳定情况进行了研究分析。计算结果显示:渗流会对明渠边坡的稳定性带来不利影响,随着开挖深度的增加,地下水位的重新调整,明渠边坡不断地产生渗流。渗流产生的渠底水压力和渗透压力对边坡的稳定不利,且影响明渠的正常施工,必须采取有效的排水措施,来降低地下水位。在保证明渠边坡开挖过程中的稳定和明渠干地施工的前提下,研究了排水井间距、深度、砂层厚度对渠道内外水头差的影响,为明渠的施工提供依据和参考。

By application of 3D finite element method, excavation process, dewatering and seepage, and slope seepage stability of the canal at Wenbo section, south-to-north water diversion project, are studied and analyzed. The calculation shows that the seepage may result in unfavorable impact to the slope stability of the open canal. With the increase of the excavation depth and the re-arrangement of the ground water table, the open canal slope continuously occur seepage. The water pressure at the canal bottom and the seepage pressure caused by the seep- age unfavorably impact the slope stability as well as the normal excavation of the open canal. Therefore, the effective dewatering measures shall be taken to lower the ground water table. In precondition of assuring the slope stability of the open canal during excavation and the excavation of the canal in dry condition, impacts on the head difference inside and outside the canal caused by spacing, depth and sand layer thickness of the dewatering wells are studied. This provides the open canal construction with basis and reference.