溇水上游古堰塞湖的发现及其水电工程意义

DISCOVERY OF ANCIENT LANDSLIDE-DAMMED LAKE IN THE UPSTREAM OF LOUSHUI RIVER AND ITS SIGNIFICANCE ON WATER AND ELECTRICITY ENGINEERING

对溇水上游河湾岩溶渗漏研究中,在湘鄂交界的溇水河谷,发现了大型古滑坡体和堰塞湖沉积粘土层并对其进行了研究。对古滑坡体和堰塞湖作了简要介绍,对一些主要问题进行初步讨论和分析。古滑坡体约2 000×104m3,进入河道长度大于1 000 m;湖相沉积层厚度大于48 m,最大出露高程284.1 m,根据14C测试,古堰塞湖形成于10 760±130~16 880±250 a BP。通过分析认为堰塞湖水位大于285 m,堰塞湖沉积粘土层中出露的高硫酸盐地下水与当时沉积环境和粘土层本身无直接联系,沿河两岸粘土层产状变化可能与再次滑坡有关联;该研究成果对当前水电工程建设和研究溇水河流发育史、现代江河灾难性地质灾害的形成演化具有一定参考价值。

During the study of karst seepage for the upstream bay area on Loushui River,in the boundary between Hunan Province and Hubei Province,the huge ancient landslide and dammed lake were found and studied.The paper stated the landslide and dammed lake in brief,and discussed and analysed some problems about them.The landslide body is about 20 million cube,and the dam is about 1000 m long.The total thickness of the clay is more than 48 m,and the highest point of the clay laying out is 284.1 m height about sea level.The 14C ages is about 10760±130 aBP and 16880±250 aBP for the upper and lower clay.It is considered that the level of the lake is more than 285 m.The high sulphate content of the groundwater flowing out from the clay is not associated with the environment of clay deposit and the clay itself.The clay trend in two bank of the river is possible made by the re-landslides.This result is of reference value for water and electricity engineering construction,and for the study of the development history of Loushui River and the formation and evolution of calamitous geological hazards of today＇s rivers.