Study On Sedimentary Characteristics And Ecological Conservation Materials Of Tuhuaba In Jiuzhai And Huanglong Area

Jiuzhai and Huanglong Area has attracted worldwide attention due to its unique travertine geology and landforms,and has been included in the"World Natural Heritage List".It has extremely high scientific research,tourism,and economic value.In recent years,the degradation and damage of some travertine landscapes has attracted the attention of scholars from all over the world.By studying the sedimentary characteristics of travertine dams,this paper uses the research results as the theoretical basis to propose a preparation method of ecological conservation material for the damage and degradation of travertine dams.The preparation method explored the feasibility of ecological conservation materials,verified its applicability in the Jiuzhai andHuanglong Area,realized the in-situ ecological conservation and restoration of the travertine dam,and provided a scientific theoretical basis for the restoration of similar karst areas.The results of the study show that the travertines on the edge stone dams in the Jiuzhai and Huanglong Area are dominated by calcite-type calcium carbonate,but the morphology of calcium carbonate crystals is affected by water chemistry and microorganisms,and the microscopic morphology of different sampling points is different.There are obvious differences in the distribution of biological communities in the travertine of Wucaichi,Zhengyanchi and Yingbinchi in Huanglong area,and the distribution of Ca on the surface of diatom shells in travertines is affected by the concentration of Ca²⁺ions in the water body.The higher the concentration of Ca²⁺ions in the water body,the higher the distribution of Ca element on the surface of the diatom shell.Further study of the layered travertine on the travertine dam of the Zhengyan Lake showed that although the mineral phase and chemical composition of each layer of travertine are the same,the Ca O content and the degree of calcite crystallinity are different.The dominant species difference between each layer is obvious,and the Si element content distribution on the surface of the diatom shell gradually increases from the outer layer to the inner layer.The base material particle gradation,additive amount and curing time will all affect the strength of travertine block.After curing,the compressive strength of the block can reach9.47Mpa.The chemical composition and mineral phase are basically the same as those of the travertine in the Jiuzhai and Huanglong Area.According to the measurement results of mercury intrusion method,it can be seen that the shaped block has the advantages of large number of pores,strong pore throat connectivity,and reasonable pore structure,and its porosity is between the laminae and clump travertine in the Huanglong Area,and the density is close to clumps travertine Comparing the micro-CT imaging and the ball-and-stick model of the block before and after freezing and thawing,it is found that the changes caused by the freezing and thawing of the block are manifested in the increase of surface pores,which gradually spread to the inside,resulting in micro-cracks.The freeze-thaw damage degradation mode of the shaped block can be summarized as the crack and spalling mode.After the in-situ deposition of the shaped block,the growth of the biological community on the surface is in benign condition,which is basically consistent with the surrounding environment and has bioaffinity.The layering of new-born travertine on the surface of the shaped block is affected by the alternating periods of high and low water and the periodic growth of microorganisms in the Huanglong Area.The in-situ deposition model of the shaped block is divided into three stages.Among them,the dissolution and recrystallization of the shaped block at the initial stage accelerate the formation of calcium carbonate.The conservation and restoration efficiency is improved,and the feasibility and applicability of the model block used in the Jiuzhai and Huanglong Area is confirmed.The study on the sedimentary characteristics of the travertine dam provides a strong theoretical basis for ecological conservation materials.The results show that the ecological conservation materials fully meet the needs of travertine landscape restoration in the Jiu-huang area,have strong feasibility and applicability,and also fill in at present,there is a gap in the research of similar restoration fields at home and abroad.