Abstract:
For the purpose of conducting a dissolution test,samples of six distinct calcite vein limestone structures from eight karst strips in the Wuhan region were chosen to examine the pore evolution law and control impact of the limestone during dissolution. Meanwhile,CT imaging was used to examine the dissolving properties and pore structure of the rocks before and after the test. The findings demonstrate that: (1)The medium-fine crystalline porphyritic limestone has the highest mass,pH value,and electrical conductivity both before and after dissolution; the pore volume rises noticeably after breakdown,and there is a clear improvement in the connection between pore structures; (2)In the calcite vein micrite and microcrystalline limestone,the proportion of tiny holes diminishes while the proportion of medium and large pores greatly rises during dissolution. When the particle size reaches the powder crystal structure,the situation is the opposite. The microcrystalline calcite vein limestone's pore throat length and comparable diameter are the easiest to form among them; (3)Calcite vein limestone has a far larger total fractal dimension than its pores and fractures combined,with fractures having a higher fractal dimension than pores. The calcite vein limestone with micrite structure has the lowest fractal dimension,whereas the calcite fine dolomite limestone has the largest fractal size. Following disintegration,the fractal dimension of the rock samples' pores and fractures varies at random; (4)Calcite veins with medium-fine grained crystalline porphyritic,micrite,and fine-grained dolomitic features gradually lose their surface permeability. The evolution law of the measured values and the estimated surface permeability values are typically in agreement,suggesting that the seepage simulation based on the μ-CT scanning data may be utilized as a backup method to assess the permeability properties of the rock mass. The study's findings can be used to better understand the various karst mechanisms and karst growth laws of limestone with calcite veins.