某面板堆石坝施工期基坑渗水成因研究
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摘要
某面板堆石坝施工期基坑发生严重渗水,影响施工正常进行。检查发现下游导流明渠由于施工质量问题,出现局部开裂导致漏水,并且漏水处下部粉土质砂发生塌陷。采用有限元法,对上游围堰、堆石坝基坑和导流渠道进行了数值建模和三维渗流场计算分析。通过对比渠道正常运行和带缺陷运行的三维渗流场和土体渗流比降的变化,揭示了渠道漏水对整体渗流场和渗流量的影响,论证了塌陷产生的原因。提出了加深防渗墙和提高渠道施工质量的建议。
The foundation pit of a concrete faced rock-fill dam(CFRD) project had seen serious seepage which affected the construction.It was found that cracks and leakage occurred at the lower open diversion channel due to bad construction quality,which had led to collapse of below silt soil.Numerical model was established and three-dimensional seepage analysis was conducted by finite element method for the upstream cofferdam,foundation pit and diversion channel.By comparing the changes of 3D seepage field and soil seepage gradient between channel in normal state and that with cracks,the authors demonstrate the impact of leakage at channel on the overall flow field and seepage discharge,discuss the causes for collapse,suggest to deepen the anti-seepage wall and improve the construction quality of channel.
The foundation pit of a concrete faced rock-fill dam(CFRD) project had seen serious seepage which affected the construction.It was found that cracks and leakage occurred at the lower open diversion channel due to bad construction quality,which had led to collapse of below silt soil.Numerical model was established and three-dimensional seepage analysis was conducted by finite element method for the upstream cofferdam,foundation pit and diversion channel.By comparing the changes of 3D seepage field and soil seepage gradient between channel in normal state and that with cracks,the authors demonstrate the impact of leakage at channel on the overall flow field and seepage discharge,discuss the causes for collapse,suggest to deepen the anti-seepage wall and improve the construction quality of channel.
引文
[1]陈慧远.土石坝有限元分析[M].南京:河海大学出版社,1988.
[2]刘奉银,刘国栋,戚长军,等.某水电站防渗墙深度对围堰渗流特性及地震稳定性影响的计算研究[J].岩土力学,2009,(S2):297-301.
[3]王峰,宋葳,孙城双.三维基坑开挖阶段地下水渗流分析[J].低温建筑技术,2009,(05):96-98.
[4]魏泽光,黄俊,许国安,等.三维稳定渗流的有限元计算[J].水利学报,1982,(1):39-47.
[5]王兆云,麻永福.新疆某水电站坝基渗流三维有限元计算与分析[J].中国水运,2009,(02):136-137.
[2]刘奉银,刘国栋,戚长军,等.某水电站防渗墙深度对围堰渗流特性及地震稳定性影响的计算研究[J].岩土力学,2009,(S2):297-301.
[3]王峰,宋葳,孙城双.三维基坑开挖阶段地下水渗流分析[J].低温建筑技术,2009,(05):96-98.
[4]魏泽光,黄俊,许国安,等.三维稳定渗流的有限元计算[J].水利学报,1982,(1):39-47.
[5]王兆云,麻永福.新疆某水电站坝基渗流三维有限元计算与分析[J].中国水运,2009,(02):136-137.
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