Experimental Study On Microbial Mineralization Of Red Sandstone Weathered Soil In Saline-alkali Environment

The grotto cultural area east of the Yellow River in Ganning and Ningxia in Northwest my country is a cultural treasure on the grassland.Under the action of natural disasters and human factors,grottoes basically have different degrees of disease,such as: sand burial and erosion,surface pulverization and spalling,and salt panning.,Efflorescence,fissures and hollow drums,etc.Chemical methods such as cement,lime or chemical grout grouting technology are usually used for repair work.These methods not only consume a lot of energy,but also cause great pollution to the environment itself,which cannot meet the requirements of resource conservation and environmental protection in the current era.Therefore,seeking new restoration methods is an important part of the restoration work of grotto buildings at this stage.The grotto culture in the east of the Yellow River in Ganning and Ningxia in Northwest my country has been affected by the dry and wet cycle for a long time,and the walls and soil have very serious problems with salt and efflorescence.In response to this situation,the MICP technology is used to repair the diseases of these grotto buildings,At the same time,it has strong resistance to salt and alkali dry and wet cycle erosion.This article takes the red sandstone weathered soil of the same material as the grotto building as the research object,and uses Bacillus oceanicus and Bacillus pasteurii to carry out the indoor experimental study of microbial induced mineralization on it,and obtains the best mineralized OD600 value of the two bacteria.Microbiologically induced mineralization test of red sandstone weathered soil under different salt and alkali environments,and laboratory test research on the resistance of microbial-induced mineralized red sandstone weathered soil to salt and alkali dry-wet cyclic erosion.The test results show that the best OD600 value of Bacillus ocellatus mineralized red sandstone weathered soil is 1.2,and the strength is 834 k Pa,and the best OD600 value of Bacillus pasteurii mineralized red sandstone weathered soil is 0.9,and the strength is 896 k Pa.In the red sandstone weathered soil with saline environment and alkaline environment,both species of bacteria can induce mineralization reaction in the metabolic process,but in the salt environment,the ability of inducing mineralization of the two species of bacteria is inhibited.In the environment,the mineralization induction ability of the two species of bacteria increased first and then decreased.From the overall comparison,the oceanic bacteria have stronger mineralization induction ability in the salt and alkali environment.Oceanic bacteria and Pasteurella induced mineralization test specimens were subjected to dry-wet cycle test in a salt and alkali environment,soaked in 3% Na Cl solution,5% Na2SO4 solution,during the dry-wet cycle process,Pasteurella induced mineralization test The specimens were severely damaged,and the specimens of oceanic bacteria-induced mineralization were slightly damaged.In the alkali environment of different concentrations,the intensity change rate of the specimens of oceanic bacteria-induced mineralization was higher than that of the Pap-induced mineralization specimens.Considering that the oceanic bacteria induced mineralization specimens are more resistant to salt and alkali dry-wet cyclic erosion.