Digitized Analysis Of Corrosion Morphology Of Exposed Carbonate Rock Surface And Study Of Material Accumulation Effect

Under the action of karst,carbonate rock surface shows rich dissolution morphology,which can be regarded as the initial state of karst landforms and is indicative of the development and evolution of karst landforms;at the same time,dissolution morphology influences the aggregation of dissolution residues and foreign materials on the rock surface,and is the basis for the formation and evolution of limestone soils.Due to the complexity of rock surface dissolution morphology,previous authors have only qualitatively described or simply measured and analysed the dissolution morphology of carbonate rocks in their natural state,making it difficult to quantitatively study the shape,area,volume and other parameters of the dissolution morphology,limiting the study of dissolution morphology and its material aggregation effect,further limiting the role of rock surface dissolution research in karst geomorphology,limestone soil formation and material migration and transformation in the key zone of karst.This paper proposes to introduce a high-precision Based on this,this paper proposes to introduce a high-precision 3D laser scanning technology to construct a digital analysis method of exposed carbonate rock surface dissolution morphology,and to quantitatively study the types and parameters of dissolution morphology in the well-protected Guangxi Langgang National Nature Reserve,which is undisturbed by humans.The main results of this study are as follows: the dissolution patterns of carbonate rocks,the karst geomorphology and the process and effect of limestone soil formation.The main results obtained in this study are as follows:1.The results show that the 3D laser scanner can obtain 3D point cloud data on the surface of carbonate rocks,reproduce and portray the shape of rock surface dissolution patterns,extract the parameters of rock surface dissolution patterns,and establish the connection between traditional description patterns and dissolution pattern parameters.It also provides a new method and a new idea for the later study of the measurement of dissolution morphology of exposed carbonate rock surfaces.2.In this study,a total of 27 dissolution patterns were investigated on the surface of two exposed limestone blocks.The results show that there are four types of dissolution patterns on the limestone rock surface,namely,17 dissolution pits,4 dissolution pans,3 dissolution basins and 4 dissolution trenches.The overall dissolution morphological parameters of the different dissolution morphology types on the rock surface are: dissolution gully > dissolution basin > dissolution pan > dissolution pit,the average length,width,depth,perimeter and surface area of the dissolution gully are 6.42 times,2.03 times,2.39 times,4.81 times and16.11 times of the dissolution pit,respectively.The rock surface dissolution patterns show different shapes and spatial combinations,mostly distributed in a combined manner,with dissolution pits being mostly bowl-den-like hollows,clustered on gentler rock surfaces,dissolution discs being mostly oval and rectangular shallow saucer-shaped,and dissolution basins being hemispherical basin-shaped and relatively larger in scale than dissolution pits and discs.The gullies are accompanied by long,stepped gullies.The larger dissolution forms,such as gullies and basins,are formed by the fusion of smaller dissolution forms,such as pits and pans,after a long period of dissolution.3.The results of the study showed that the dry weight and moisture ratios of the aggregated materials in the rock surface dissolution form of exposed carbonate rocks were negatively correlated,and the aggregated materials in the rock surface dissolution form could be further classified into four categories: soil,roots and dead material,rocks and animal residues;the dry weight ratios of the aggregated materials in the rock surface dissolution form were(75.80%)> dissolution pans(75.37%)> dissolution pits(70.14%),and the proportion of water in the pits(29.86%)> dissolution pans(24.63%)> dissolution pits(24.20%)>dissolution pans(18.27%).The highest percentages of soil(95.24%),roots and dead material(8.76%)and stones(17.69%)in the solution pits and animal remains(0.82%)in the solution basins were found in the solution pans.In terms of the amount of material aggregated by the dissolution form of the exposed limestone rock surface,the number of wet weights was dissolution gully(1289.95g)> dissolution pit(94.95g)> dissolution basin(45.52g)>dissolution pan(12.74g),the number of moisture was dissolution pan(3.14g)< dissolution basin(8.32g)< dissolution pit(28.35g)< dissolution gully(312.13g),and the number of dry weights was dissolution gully(977.82g)> soluble pits(66.60g)>soluble pots(37.22g)>soluble pans(9.60g).4.The number of dissolved morphological aggregates on the surface of bare carbonate rocks varies with the increase of dissolved morphological parameters.The influence of dissolved morphological parameters on the number of dissolved morphological aggregates(wet weight and dry weight)is depth >surface area >width >length >perimeter.In addition to width,the influence degree of the remaining rock surface corrosion morphology parameters on the water accumulation amount of corrosion morphology material is depth >surface area >length >perimeter.The corrosion morphology parameters of rock surface are positively correlated with the number of corrosion morphology aggregates,which has a promoting effect.