库水位间歇性下降对堆积体滑坡稳定性的影响
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摘要
针对库水位快速下降不利于滑坡稳定的现状,提出库水位以间歇性方式下降,即在传统库水位持续性下降分析的基础上,以三峡库区某一堆积体滑坡为例,利用Geo-Studio软件详细分析了在库水位不同间歇时间和多阶段间歇下降条件下堆积体滑坡稳定情况。结果表明:库水位实行间歇性下降,间歇时间有助于滑坡体内孔隙水压力消散,减小库水快速下降引起的地下水回落的滞后性,有利于水力梯度降低;相比库水位持续性下降,滑坡稳定性得到提高,但稳定系数与间歇时间并不呈正比例关系;在库水位实行多阶段间歇性下降后,提高的程度明显增大,达到5%以上。为了使滑坡稳定性提高的效果达到最佳,应合理地安排库水位下降和间歇时间。
Rapid drawdown of reservoir water level is adverse to landslide stability. In view of this,we propose that the reservoir water level declines intermittently. On the basis of traditional analysis of persistent drawdown of water level,we analyzed the influences of intermission and intermittent drawdown of water level on the stability of landslide by using Geo-Studio software. An accumulation landslide in Three Gorges reservoir area was taken as an example. Research results show that intermission is in favor of the dissipation of pore water pressure in the landslide;meanwhile,lag effect of groundwater level's decrease caused by rapid drawdown of reservoir weakens and hydraulic gradient decreases; when we compare reservoir intermittent drawdown with reservoir persistent drawdown,landslide stability factor of the former is bigger,but stability factor is not in proportion with intermission; under the multistage intermittent drawdown of reservoir,stability factor has obviously improved,which is greater than 5%. Finally,in order to optimize the landslide's stability,we should reasonably arrange reservoir drawdown and intermittent time.
Rapid drawdown of reservoir water level is adverse to landslide stability. In view of this,we propose that the reservoir water level declines intermittently. On the basis of traditional analysis of persistent drawdown of water level,we analyzed the influences of intermission and intermittent drawdown of water level on the stability of landslide by using Geo-Studio software. An accumulation landslide in Three Gorges reservoir area was taken as an example. Research results show that intermission is in favor of the dissipation of pore water pressure in the landslide;meanwhile,lag effect of groundwater level's decrease caused by rapid drawdown of reservoir weakens and hydraulic gradient decreases; when we compare reservoir intermittent drawdown with reservoir persistent drawdown,landslide stability factor of the former is bigger,but stability factor is not in proportion with intermission; under the multistage intermittent drawdown of reservoir,stability factor has obviously improved,which is greater than 5%. Finally,in order to optimize the landslide's stability,we should reasonably arrange reservoir drawdown and intermittent time.
引文
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[10]黄康鑫,郝明辉,徐富刚,等.水位骤变触发库岸堆积层滑坡的物理模型试验及机理分析[J].工程地质学报,2014,22(增l):232-237.
[11]易武,董志鸿,黄海峰,等.三峡库区树坪滑坡地下水渗流场分析[J].工程地质学报,2014,22(增l):70-76.
[12]刘博,李江腾,王泽伟,等.非饱和土渗流特性对库岸边坡稳定性的影响[J].中南大学学报(自然科学版),2014,45(2):515-520.
[13]谢剑明.降雨对滑坡灾害的作用规律研究[D].武汉:中国地质大学,2004.
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[15]缪海波.三峡库区侏罗系红层滑坡变形破坏机理及预测预报研究[D].武汉:中国地质大学,2012.
[2]刘新喜,夏元友,张显书,等.库水位下降对滑坡稳定性的影响[J].岩石力学与工程学报,2005,24(8):1439-1444.
[3]刘才华,陈从新,冯夏庭.库水位上升诱发边坡失稳机理研究[J].岩土力学,2005,26(5):769-773.
[4]周彬,刘贵应,梁庆国.三峡库区周期性库水位变化对抗滑桩加固效果非饱和流固耦合分析[J].路基工程,2012,(2):59-64.
[5]郑颖人,时卫明,孔位学.库水位下降时渗透力及地下水浸润线的计算[J].岩石力学与工程学报,2004,23(18):3203-3210.
[6]涂国祥,邓辉,黄润秋.水位变动速度对某库区岸坡堆积体稳定性的影响[J].四川大学学报(工程科学版),2011,43(4):63-70.
[7]原先凡,邓华锋,蔡健,等.库水位升降条件下临近坝址区堆积体边坡稳定性分析[J].水电能源科学,2013,31(9):135-137.
[8]向玲,王世梅,王力,等.动水压力型滑坡对库水位升降作用的响应——以三峡库区树坪滑坡为例[J].工程地质学报,2014,22(5):876-882.
[9]卢书强,易庆林,易武,等.库水下降作用下滑坡动态变形机理分析——以三峡库区白水河滑坡为例[J].工程地质学报,2014,22(5):869-875.
[10]黄康鑫,郝明辉,徐富刚,等.水位骤变触发库岸堆积层滑坡的物理模型试验及机理分析[J].工程地质学报,2014,22(增l):232-237.
[11]易武,董志鸿,黄海峰,等.三峡库区树坪滑坡地下水渗流场分析[J].工程地质学报,2014,22(增l):70-76.
[12]刘博,李江腾,王泽伟,等.非饱和土渗流特性对库岸边坡稳定性的影响[J].中南大学学报(自然科学版),2014,45(2):515-520.
[13]谢剑明.降雨对滑坡灾害的作用规律研究[D].武汉:中国地质大学,2004.
[14]DZ/T0218—2006,滑坡防治工程勘查规范[S].北京:中国标准出版社,2006.
[15]缪海波.三峡库区侏罗系红层滑坡变形破坏机理及预测预报研究[D].武汉:中国地质大学,2012.