摘要
坡面型泥石流是先产生滑坡,而后迅速转变为泥石流的过程。它兼有滑坡和泥石流的一些特征。宁陕县城周围坡面型泥石流发育于中泥盆统地层的陡坡上。发生坡面流的斜坡残坡积土主要为粘性土,含少量块石或碎石,级配较好,且土层厚度小。土中粘土矿物由伊利石/蒙脱石、伊利石和高岭石组成,具低—中等膨胀性,因而其渗透性低-极低。遇持续暴雨作用,此种残坡积土局部发生启动下滑-流土,进而在动水压力作用下下泻造浆形成坡面泥石流。坡面型泥石流沟浅而宽,大多顺斜坡的倾向发生,也有斜交坡向而沿岩层走向发生,是沟谷型泥石流发育的雏形。因而,有必要进一步研究坡面型泥石流的动力学特征,为泥石流灾害预警提供科学依据。
The occurrence of slope mudflow is a process in which a landslide first occurs and then rapidly changes into mudflow. It has some properties of landslide and mudflow concurrently. The slope mudflow around the seat of Ningshaan County occurs on a steep slope of Middle Devonian strata. The eluvial soils on slopes where surface flow occurs are mainly clayey soils with some blocks or debris. They have good grading distribution and a thin soil horizon. The clay minerals in the eluvial soils consist of illite/ montmorillonite, illite and kaolinite with low and intermediate dilatability, so their permeability is low or very low. When rainstorms persist, such soils will start to slide down the slope and be eroded, and furthermore, they rush down and form slurry, thus giving rise to slope mudflow. The canyons of slope mudflow are shallow and wide and mostly occur downslope, and sometimes those that obliquely intersect the slope direction but are parallel to the strike of the strata are also seen. They are embryos of canyon type mudflow. Therefore, it is necessary to study the dynamic features of slope type mudflow to provide a scientific basis for early-warning of mudflow disasters.
出处
《地质力学学报》
CSCD
2006年第2期219-227,共9页
Journal of Geomechanics
基金
国家自然科学基金(编号40472153)
科研院所社会公益类研究专项基金(编号2004DEI100260)资助
关键词
坡面型泥石流
滑坡
形成条件
诱发机制
陕西宁陕
slope type mudflow
landslide
formation condition
inducing mechanism
Ningshaan County, Shaanxi
