Study On Evolution Features About Loess Plateau Of Kongtong Of Pingliang City

"The cracking of the loess tableland in the Loess Plateau will become more and more serious,and it’s not a repetitive process.","Reinforce the gully to protect the loess tableland" has become a hot topic.The paper takes Kongtong region of Pingliang as the research object,by geological survey at field,data collection and arrangement,extracting the valley network and the plateau line of the study area by GIS technology,to analyze the spatial distribution and morphological characteristics of the tableland line and valley network of the study area.Statisticing the situation about the deformation of the slope,and explore the interaction between the loess tableland and the valley network and the slope deformation,to reveal the evolution mechanism of the loess tableland.The main research results as follows:(1)With the Jin River as the boundary,there are obvious differences and parallel characteristics between the the north and south sides of the river about the morphology and spatial distribution characteristics of the loess tableland in the study area.The long-axis extension direction of loess tableland is 302°~315°in the north Jin River.It is It is mainly distributed in Caofeng,Baimiao,Suoluo and other places.The shape is long strips,and the loess Plateautilts in 6-degree gradient to the southeast;the long axis extension direction of the loess tableland in the area south is 190°~213°,and the slope ratio of the loess tableland along the major axis is about 3‰.(2)The morphological and spatial distribution characteristics of loess tableland are closely related to the morphology and spatial distribution of the gully system.The valley network of the study area is complex and the branch ditch is extremely developed.Its spatial distribution is characterized by parallelism,symmetry and equal spacing.The influence of the valley on the evolution of the loess tableland is mainly reflected in the trace erosion of the gully head and the lateral erosion of the gully wall.The gully head erosion is strong and the development is active.The loess tableland is in a strong erosion stage.(3)The influence of the slope evolution on the evolution of the loess tableland is divided into abrupt and gradual changes.The deformation of slope due to deformation and failure of the slope is often not a single deformation failure mode,but is a cumulative result of multiple deformation failures under common and successive effects.(4)The degradation of the loess tableland is the result of the joint action of the development of the valley and the evolution of the slope.On the one hand,the development of the gully has led to a gradual widening of slopes on both sides.Mutation and gradual evolution of the slopes have continuously acted on the loess tableland,resulting in a sharp decrease in the area of the loess;on the other hand,the development of the slope promoted the formation of the valleyAnd traceable erosion,eventually leading to the degradation of the loess tableland.