Study On Macroscopic And Microscopic Characteristics And Mechanism Of Yunnan Red Clay Under Acid Rain Erosion

This paper discussed the Yunnan laterite's shear character under the different proportion of HNO3 in acid rain,then compared the variation coefficient and average evariation coefficient under the different content of HNO3 in acid rain,at last analyzed the interaction mechanisms between acid rain and laterite.Author made the simulated acid rain according to the characteristics of Yunnan acid rain,and used the method of soaking and dry-wetcycle test to do experiment.The effect is content of HNO3 and pH of acid rain.Thetest results under nomalcontent of HNO3 show that:The laterite's shear character and its related index will be reduced when soaking(dry-wetcycle)under the nomal acid rain.The smaller the pH of the acid rain and the longer the soaking(dry-wetcycle)times,the more the shear character reduced.Shear character and its related index fluctuating increased with the increase of the pH value,while the Mass decreased with the increase of the pH value.On the first time of soaking(dry-wetcycle),shear character and its related index decreased the most.After that,it fluctuated with the soaking(dry-wetcycle)times,and the Mass fluctuating decreased as the longer of soaking(dry-wetcycle)times.Thetest results under vary content of HNO3 show that:The laterite's shear character will be reduced when soaking(dry-wetcycle)under the vary content of HNO3 acid rain.Shear character fluctuating increased with the increase of the HNO3 content.The smaller the pH of the acid rain,the more the shear character reduced.Shear character fluctuating decreased with the increase of soaking(dry-wetcycle)times.The Mass increased with the increase of the HNO3 content.The variation coefficient show that:The change of laterite's shear character could be express by variation coefficient and average variation coefficient,The average variation coefficient similar to variation coefficient underthe r:ight pressure of 200,300kPa.so it could be replace by variation coefficient underthe right pressure of 200,300kPa.Micro structure test resultsunder vary content of HNO3 show that:The laterite grainsis compact and the porosity is low,so the laterite's shear character is higher under soaking 5days(dry-wetcycle 5 times).The laterite grainsis loosely and the porosity is more,so the laterite 's shear character is lower under soaking 1 or 9 days(dry-wetcycle1 or 9 times).The void ratio of laterite is low,so the porosity is low and the grainsis compact,so the laterite's shear character andvariation coefficient is higher under soaking 5days(dry-wetcycle 5 times).The void ratio of laterite is higher,so the porosity is higherand the grainsis loosely,so the laterite's shear character and variation coefficient is lower under soakingl or 9 days(dry-wetcyclel or 9 times).The electric conductivity under vary content of HNO3 show that:The electric conductivity is higher under soaking 5days(dry-wetcycle 5 times),because of the laterite contain a lot of crystal and it have a higher density.thenit caused the laterite's shear character andvariation coefficient is higher.The electric conductivity is lower under soakingl or 9 days(dry-wetcyclel or 9 times),because of the laterite contain a little crystal and it have a lower density.Then it caused the laterite's shear character and variation coefficient is lower.The interaction process between of acid rain and laterite:The interaction process between of acid rain and laterite under the soaking,and it included the swelling softening,alteration,gelatum,corrosion crystallization,corrosion substitute etc.The interaction process between of acid rain and laterite under the dry-wet cycles,and it included the humidifying,desorption of moisture,dry-wetcycle.All of the interaction under the soking and dry-wetcycles,These process occurred in water softening,water alteration,acid alteration,colloid formation,colloid destruction,crystallization,substitute etc.