Study On Formation And Evolution Of Karst Caves In Shuanghe Cave,Suiyang

Shuanghe cave in Suiyang,Zunyi,Guizhou Province is a large-scale dolomite cave developed in the National Geopark.It is the longest dolomite cave in the world and the largest celestite cave in the world.According to the latest exploration results,Shuanghe cave has complex structure,water cave and dry cave coexist,with a depth of more than 550 meters.It is composed of 8 main tunnels,more than 200 branch tunnels,5 underground rivers and 34 holes on the upper,middle and lower floors.According to the known research,the nature of dolomite is not easy to develop into large-scale caves.For example,in the previous research,Zhi Jin Dong National Geopark in Guizhou Province is compared with Shuanghe cave dolomite cave in Suiyang,which is distributed in four layers,but the development of Zhi Jin Dong is mainly in the gray oolitic bright limestone stratum in the upper part of Yelang formation and huangchunba section?t1y2?in the lower Triassic system.According to the data investigation,the Cambrian and Ordovician semi confined platform carbonate rocks are widely developed in Shuanghe cave area of Suiyang,and the large-scale dolomite caves formed have certain research significance.This paper takes Shuanghe cave dolomite cave in Suiyang as the research object,based on previous data,field investigation and monitoring of cave environment gas,adopts the indoor physical experiment research method to study the influencing factors and conditions of cave development,and finally summarizes the evolution mechanism,proposes the formation and evolution mechanism of Shuanghe cave dolomite cave in Suiyang,which provides the theory for forming large and stable caves of dolomite On the basis.The main research contents and achievements are as follows:?1?According to the data,Shuanghe cave area in Suiyang was in shallow sea sedimentary environment for a long time,and developed a large number of gypsum layers.The dolomite in Shuanghe cave area belongs to the dolomite of typical platform evaporation facies.Based on the known data,this paper makes a supplementary explanation and detailed analysis of the various characteristics of Shuanghe cave,and studies the distribution characteristics,morphological characteristics and cave environment characteristics of the cave The results show that the chemical characteristics of water and the content of carbon dioxide have an effect on the formation of Shuanghe cave.?2?According to the factors influencing the formation of Shuanghe cave,the variables in the experiment process are determined,and dolomite mixed dissolution experiment is carried out.It is found that the dissolution rate of dolomite is faster under the condition of dolomite mixed dissolution with celestine and gypsum.By changing the content of Sr/Ca in the experiment,it is found that the increase of SO₄^2-ion in the solution will accelerate the de dolomitization,and the higher the content of Sr in the solution,the faster the dissolution rate of dolomite.In this paper,it is considered that the mixed corrosion effect,the same ion effect and the ion strength effect are the results of the interaction.?3?The samples were collected and tested in Shuanghe cave karst cave.After dissolution,the samples were tested by SEM and EDS.it was found that the consumption rate of Sr and Ca was different in the dissolution process,and the same ion effect had a positive effect on the dissolution of the samples.Compared with the cave development analysis of Shuanghe cave,Shuanghe cave belongs to seasonal water flow.In some seasons,when the water flow is slow or almost no flow,it gives a period of cave restoration.The precipitation produced by dissolution is attached to the surface,pores,joints and other places of the rock stratum,strengthening the stability of the rock stratum,making the whole dolomite better form a cavity and not easy to collapse,promoting large-scale stability The formation of dolostone cave in Ding.?4?According to the conclusion of the experiment and the final formation and evolution,the advantage of the formation of Shuanghe cave dolomite cave in Suiyang is that there are a lot of celestine and gypsum in the cave.The mixed solution formed by the mixed solution accelerates the dissolution reaction of dolomite,and the precipitate formed by the dissolution reaction is attached to the rock layer,which explains the cave in the lower layer The reason for the formation of caves is generally large,which has a positive role in promoting the long-term stability of Shuanghe cave.At the same time,depending on the formation conditions of Shuanghe cave area,large-scale dolomite karst caves are formed.?5?According to the study,it is concluded that the whole formation and evolution stage of Shuanghe cave is roughly studied.The whole formation process of Shuanghe cave area is that the dolomite stratum has gone through the stage of structural fracture development-groundwater,surface water dissolves through gypsum rock-formation of independent holes-water flow continues to dissolve the rock strata-dissolution and connection of holes and caves-formation stage of small karst caves-mixed dissolution and part of collapse to form a large one The evolution process of karst cave in the stage of multi-layer karst cave formed by karst cave and crustal uplift.Based on the study of the formation and evolution of the karst caves developed in Shuanghe cave,this paper further explains the basic characteristics and formation rules of Shuanghe cave,which is of great value to the rational development and protection of Shuanghe cave.