| With the rapid development of modern industry,the environmental pollution is increasingly serious,which leads to the problem of acid rain has become one of the global environmental problems.The acidic medium in acid rain will penetrate in the rock pores and defects and and vary in degrees of dissolution and erosion of certain mineral crystals or particles resulting in physical and mechanical properties of rock change significantly and the durability problems of rock material have become increasingly prominent,which will cause huge economic losses.The paper uses the PH=2 sulfate solution simulating the indoor accelerated corrosion test,through monitoring the concentration of Na+,K+,Mg2+, Ca2+ in different stages of soaking solution,PH value changes in the sulfuric acid solution and wet rock samples with dry rock samples mass change to quantitative analysis of the variation of rock samples in the corrosion process of physical and chemical properties.By the different stages of immersion for the sandstone of CT scanning test to obtain the CT scans and microscopic parameters,from the microscopic point of view to analysis the effects of microscopic parameters during etching of rock density and quality,the main research results are summarized as follows:1. The sandstone sample in H2SO4 solution soak, the PH of the solution and drying sample quality change presents the obvious stage characteristics. At each stage(30d) PH value growth trends of the sulfuric acid solution, soaking in the whole stage(0~270d) drying to the quality of the sample decreases, wet sample showed a trend of decrease after the first increase in quality.2.Through monitoring cations such as Na+,K+,Mg2+,Ca2+ of PH=2 sulfuric acid solution in the different stages shows that,Ca2+ dissolution rate showed a gradualdecreasing trend, the first stage(0~30d) dissolution rate reaches a maximum2.4mg/d;Mg2+ dissolution rate in the soaking process showed a tendency to increase after the first decrease, the minimum rate of dissolution occurs in the fifth stage(120~150d),a value of 0.25mg/d;K+ dissolution rate of the previous five stages is relatively stable, in the seventh stage(180~210d) reaches the minimum0.16mg/d.Maximum and minimum values of the dissolution rate of Na+ occurs in the first stage(0~30d) and stage IV(90~120d),the values were 1.25mg/d and 0.29mg/d.3.By CT image analysis of microscopic parameters give a wet rock sample CT number of different stages of soaking with immersion time continued increasing first and then decreasing trend,by soaking three phases(0~90d) come to the maximum number of CT 2190.33 by the growth of 1.87%,followed by immersion process decreases the number of CT,and soaked dried rock samples at different stages of the CT number decreased as the soaking time.Wet and dry rock sample rock sample variance CT showed a trend first decreased and then increased after the third stage(0~90d) ends,CT minimum variance reached 264.54 and 262.6, respectively, in the ninth after stage(0~270d) end CT variance increase to a maximum of 280.35 and284.21,respectively,the corresponding growth rates were 5.98% and 8.66%.4.By means of a CT scan tests and chemical kinetics analysis of microscopic damage mechanism by acid corrosion sandstone were analyzed and quantified by the establishment of a microscopic model of acid corrosion sandstone,depth and deduced that the number of CT acid corrosion sandstone Infiltration the relationship between the density to achieve the organic combination of microscopic and macroscopic mechanics.5.The establishment of a dynamic model of acid-rock reaction,derived acidic environment deteriorated relationship rock strength,has been acid concentration diffusion range of variation over time, predict the strength of the deterioration law of large volume of rock slope engineering,water conservancy and civil engineering life prediction project provides an effective way. |
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