Research On Karst Characteristics And Development Law Of Dongshan In Caoba Town, Mengzi City

The Caoba Dongshan karst development area is located in Mengzi City,Yunnan Province,and belongs to the Nandong cave area.In order to further explore the Nandong underground river pipeline concentration area,find out the karst hydrogeological conditions and environmental geological problems in the area,provide theoretical and technical basis,study the dissolved development characteristics of the rock area,evaluate the karst development degree,and summarize the karst development law is particularly important.On the basis of collecting the research data of the predecessors,this paper obtains the geological and hydrogeological data of Mengzi Dongshan through means of drilling,tracer test and water quality analysis through field geological survey.The karst characteristics of the area were systematically analyzed by GIS software to study the influencing factors of karst development and karst development laws,and the fuzzy mathematics method was used to comprehensively evaluate the karst development degree of the study area.Get the following recognition:The karst development patterns in the study area are diverse,and the dissolution of depressions,sinking holes,funnels,and dark rivers are all developed.The karst depressions are distributed in a bead-like manner along the valleys,nested in size and size;the falling water caves and the funnel are scattered;the underground dark river has the south cave and its three tributaries.Through the study of karst characteristics,it is found that the more abundant the groundwater is,the stronger the karst is,and the more the karst is developed;the underground dark river,karst depression and fissure trend are consistent with the fault strike,especially the underground dark river fault zone;the number of karst in the tensile fracture affected zone Tectonic movement controls the stratification of karst development;topograpHy and tectonic faults jointly control the morpHology of karst.The concentrated development of the funnel and the falling water hole can be an important symbol for the search for the dark river.The degree of karst development of each evaluation unit was determined by fuzzy mathematics evaluation.The strong karst development area of Caoba Dongshan accounts for 75%of the total area,the middle area accounts for 17%,and the weak area accounts for 8%.The strongly developed areas are mainly dolomite,gray dolomite and limestone in the T₂g²,T₁y³ and T₂g¹ strata.The various karst forms are complete,the quantity is large,the concentration is high,and the underground is mostly developed with the dark river pipeline.The evaluation results are consistent with the actual situation,and the karst development degree of each region can be quantitatively evaluated by this method.