湖南临湘贺畈沟灾害性泥石流成因分析和启示
|
摘要
2011年6月10日,属湿润、低地震烈度区的湖南临湘贺畈沟暴发了历史罕见的特大泥石流灾害。为探明此次泥石流灾害的成因,在现场勘查工作的基础上,结合室内试验,划分了泥石流发生前贺畈沟流域的干旱等级,分析了长历时干旱对沟内花岗岩残积土物理力学性质的影响,计算了花岗岩残积土饱和所需的降雨量和时间,得出了此次泥石流灾害的成因:源区花岗岩残积土的垂直分层特征,决定了土体极易从细颗粒含量高的表层起动;前期长历时干旱导致土体表层沿细颗粒含量多的部位开裂,土体局部渗透性加强;在后期短历时强降雨作用下,雨水沿干裂缝等表层通道下渗,土体中的细颗粒发生运移、富集并形成局部隔水层,土体强度降低;随着降雨的进行,隔水层上部土体中孔隙水压力升高,土体破坏并液化形成泥石流。相关结论对于开展花岗岩残积土起动形成泥石流过程特征及机理研究具有启示意义。
In order to find out the genesis of the extraordinary debris flow disaster which took place in Hefangou gully of Hunan Province,where is a wet area of low seismic intensity,on June 10th in 2011,the drought grade of Hefangou Basin before the disaster was determined and the effect of lasting drought on the physical and mechanical characters of the granite residual soil was analyzed on the basis of field investigation and laboratory test.Besides,the rainfall quantity and time required to saturate the granite residual soil was calculated.Then the genesis of the debris flow was obtained: the vertical layered characteristic of the granite residual soil determined that the soil can easily start from the surface with high content of fine particles;early long duration drought cracked the soil structure and speeded up the soil weathering along the part with high content of fine particles near ground surface,which increased the permeability of the soil;later heavy rainfall of short duration caused the rainwater to infiltrate along the cracks on the soil surface with fine soil particles moving,enriched and then formed the impermeable layer of soil,the strength of the soil decreased;with the continued heavy rainfall,the pore water pressure above the impermeable layer in the upper soil soared to some extent,the soil failed and was liquefied to form the debris flow.
In order to find out the genesis of the extraordinary debris flow disaster which took place in Hefangou gully of Hunan Province,where is a wet area of low seismic intensity,on June 10th in 2011,the drought grade of Hefangou Basin before the disaster was determined and the effect of lasting drought on the physical and mechanical characters of the granite residual soil was analyzed on the basis of field investigation and laboratory test.Besides,the rainfall quantity and time required to saturate the granite residual soil was calculated.Then the genesis of the debris flow was obtained: the vertical layered characteristic of the granite residual soil determined that the soil can easily start from the surface with high content of fine particles;early long duration drought cracked the soil structure and speeded up the soil weathering along the part with high content of fine particles near ground surface,which increased the permeability of the soil;later heavy rainfall of short duration caused the rainwater to infiltrate along the cracks on the soil surface with fine soil particles moving,enriched and then formed the impermeable layer of soil,the strength of the soil decreased;with the continued heavy rainfall,the pore water pressure above the impermeable layer in the upper soil soared to some extent,the soil failed and was liquefied to form the debris flow.
引文
[1]国家地震局震害防御司.中国历史强震目录(公元前23世纪-公元1911年)[M].北京:地震出版社,1995.
[2]国家地震局震害防御司.中国近代地震目录(公元1912年-1990年,Ms≥4.7)[M].北京:中国科学技术出版社,1999.
[3]陈宁生,杨成林,周伟,等.泥石流勘查技术[M].北京:科技出版社,2011.
[4]田湖南,孔令伟.细粒对砂土持水能力影响的试验研究[J].岩土力学,2010,31(1):56-60.
[5]孔令伟,李新明,田湖南.砂土渗透系数的细粒效应与其状态参数关联性[J].岩土力学,2011,32(增):21-26,41.
[6]矫滨田,鲁晓兵,王淑云,等.土体降雨滑坡中细颗粒运移及效应[J].地下空间与工程学报,2005,1(7):1014-1016.
[7]陈晓清,崔鹏,冯自立,等.滑坡转化泥石流起动的人工降雨试验研究[J].岩石力学与工程学报,2006,25(1):106-116.
[8]周健,姚志雄,张刚.砂土渗流过程的细观数值模拟[J].岩土工程学报,2007,29(7):977-981.
[9]Seiler R.,Hayes M,Bressan L.Using the standardized precipitationindex for flood risk monitoring[J].International Journal of Climatolo-gy,2002,22:1365-1376.
[10]吴能森.花岗岩残积土的崩解性及软化损伤参数研究[J].河北建筑科技学院学报,2006,23(3):58-62.
[11]陈晓平,周秋娟,蔡晓英.高液限花岗岩残积土的物理特性和剪切特性[J].岩土工程学报,2011,33(6):901-908.
[12]Dai Fuchu,C.F.Lee,Wang Sijing.Analysis of rainstorm-inducedslide-debris flows on natural terrain of Lantou Island,Hong Kong[J].Engineering Geology,1999,51:279-290.
[13]Pradel D,Raad G.Effect of permeability on surficial stability of ho-mogenous slopes[J].Journal of Geotechnical Engineering ASCE,1993,119(2):315-332.
[14]唐朝生,施斌,刘春,等.黏性土在不同温度下干缩裂缝的发展规律及形态学定量分析[J].岩土工程学报,2007,29(5):743-749.
[15]陈中学,汪稔,胡明鉴,等.黏土颗粒含量对蒋家沟泥石流启动影响分析[J].岩土力学,2010,31(7):2197-2201.
[16]黄运飞,冯静.计算工程地质学[M].北京:兵器工业出版社,1992.
[17]高冰,周健,张娇.泥石流启动过程中水土作用机制的宏细观分析[J].岩石力学与工程学报,2011,30(12):2567-2573.
[2]国家地震局震害防御司.中国近代地震目录(公元1912年-1990年,Ms≥4.7)[M].北京:中国科学技术出版社,1999.
[3]陈宁生,杨成林,周伟,等.泥石流勘查技术[M].北京:科技出版社,2011.
[4]田湖南,孔令伟.细粒对砂土持水能力影响的试验研究[J].岩土力学,2010,31(1):56-60.
[5]孔令伟,李新明,田湖南.砂土渗透系数的细粒效应与其状态参数关联性[J].岩土力学,2011,32(增):21-26,41.
[6]矫滨田,鲁晓兵,王淑云,等.土体降雨滑坡中细颗粒运移及效应[J].地下空间与工程学报,2005,1(7):1014-1016.
[7]陈晓清,崔鹏,冯自立,等.滑坡转化泥石流起动的人工降雨试验研究[J].岩石力学与工程学报,2006,25(1):106-116.
[8]周健,姚志雄,张刚.砂土渗流过程的细观数值模拟[J].岩土工程学报,2007,29(7):977-981.
[9]Seiler R.,Hayes M,Bressan L.Using the standardized precipitationindex for flood risk monitoring[J].International Journal of Climatolo-gy,2002,22:1365-1376.
[10]吴能森.花岗岩残积土的崩解性及软化损伤参数研究[J].河北建筑科技学院学报,2006,23(3):58-62.
[11]陈晓平,周秋娟,蔡晓英.高液限花岗岩残积土的物理特性和剪切特性[J].岩土工程学报,2011,33(6):901-908.
[12]Dai Fuchu,C.F.Lee,Wang Sijing.Analysis of rainstorm-inducedslide-debris flows on natural terrain of Lantou Island,Hong Kong[J].Engineering Geology,1999,51:279-290.
[13]Pradel D,Raad G.Effect of permeability on surficial stability of ho-mogenous slopes[J].Journal of Geotechnical Engineering ASCE,1993,119(2):315-332.
[14]唐朝生,施斌,刘春,等.黏性土在不同温度下干缩裂缝的发展规律及形态学定量分析[J].岩土工程学报,2007,29(5):743-749.
[15]陈中学,汪稔,胡明鉴,等.黏土颗粒含量对蒋家沟泥石流启动影响分析[J].岩土力学,2010,31(7):2197-2201.
[16]黄运飞,冯静.计算工程地质学[M].北京:兵器工业出版社,1992.
[17]高冰,周健,张娇.泥石流启动过程中水土作用机制的宏细观分析[J].岩石力学与工程学报,2011,30(12):2567-2573.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心