陕北黄土区切沟内陷穴发育特征研究

通过对陕北黄土区六道沟流域切沟内陷穴进行调查和统计分析,探讨陷穴的发育形态、分布特征及其影响因素。结果表明:陷穴主要形态类型有浅碟形、漏斗形、竖井状以及葫芦状,其断面形态接近于圆形或椭圆形,陷穴形态规模相对偏小,处于成熟期的比例达72.8%;陷穴长轴、短轴和深度之间均具有显著的正相关关系,其中长轴和短轴之间具有较好的线性关系;陷穴主要发育位置为沟道中上游及支沟沟头处,多与黄土桥和跌水相伴而生;切沟为陷穴的形成和发育提供了条件,陷穴亦可促进切沟进一步发展。上述结果完善了切沟内陷穴的发生发育特点和空间分布特征,为深入认识陷穴侵蚀机理,进一步研究陷穴侵蚀状况、陷穴与切沟发育关系以及区域水土流失治理等提供了基础。

Development Characteristics of Sink Holes in Gullies on the Northern Loess Plateau

We discussed the morphology,distribution and influence factor of sink holes in gullies on the Northern Loess Plateau through field investigation and statistical analysis.The results showed as follows:(1) The morphological types of sink holes were distinguished as being shallow dish,funnel-shaped,shaft-shaped and gourd-shaped.Typical plane forms tended to be circle and oval in shape.Their evolvement stages were classified into youthful stage,mature stage and disappearance stage,and those in mature stage accounted for 72.8％.The sink holes were relatively small in dimension,and (2) Significant correlations among various shape parameters were found,and the relationship between major axis and minor axis was fitted as significant linear equation.(3) Sink holes in gully mainly appeared in the upstream channel and branch head of the gullies,and accompanied loess bridge and gully-head waterfall in general.(4) Gullies provided development space for sink holes,while sink holes would benefit the promotion of gully erosion.These findings enriched the knowledge of sinkhole morphology and distribution in the gullies.It would be helpful for deeply understanding piping erosion and its relation with gullies as well as soil erosion control in the Northem Loess Plateau.