甘肃黄土台塬区农业过量灌溉引起的滑坡灾害

黄土台塬区过量农业灌溉可引起严重的滑坡灾害。其中以甘肃省永靖县黑方台提灌区的滑坡灾害最为典型。黑方台黄土台塬自20世纪60年代开始农业提水灌溉，受其独特的地质地貌控制，在灌溉水大量入渗的诱发下，滑坡灾害十分严重。主要有黄土滑坡和黄土一基岩滑坡两种类型，分别具有高速远程和低速近程滑动的特点。过量灌溉引发的滑坡灾害具有滞后性、群发性和频发性等显著特征，且在季节分布上主要集中在冻融期(3月)和雨季(7月)。实践表明，对过量灌溉引发的滑坡灾害应以预防为主，治理为辅。改变灌溉方式和采取包括工程治理措施、排水措施、生物措施在内的综合治理措施是行之有效的防治措施。

Landslide induced by over-irrigation in loess platform areas in Gansu Province

Over-irrigation can induce serious landslides in loess platform areas,of which the landslide in Heifangtai irrigation area of Yongjing County,Gansu Prouince is the most typical one.The irrigation agriculture in Heifangtai began in the 1960s.A lot of irrigation water seep into loess because of its typical geological and geomorphic conditions,which brings into serious landslide problems.The landslides in Heifangtai can be divided into 2 categories:loess landslides and loess-bed rock landslides,with the characteristics of high speed-long distance and low speed-short distance,respectively.Landslides caused by over-irrigation have the characteristics of hystertic,group and frequent.Many of them accur in the thaw period(March) and the rainy season(July).Faced such landslides,people should make precaution the first place,and engineering treatment the second place.Change of irrigation,and synthesized treatment including engineer-treatment,drainage and biological treatment are efficient ways to reduce the disaster.