Experimental Study On Microbial Grouting Reinforcement Of A Metal Mine Tailings Under The Action Of Seepage Field

Microbial-induced calcium carbonate precipitation（MICP）technology for soil reinforcement is a new type of green reinforcement technology.Aiming at the problem that seepage is one of the main factors causing tailings dam instability,the use of MICP technology is used to develop the Contrast test of tailings reinforcement under the action of seepage field.And through the finite element numerical simulation of the working conditions of the tailings dam before and after the grouting reinforce-ment under the action of the seepage field.The results of this paper are as follows:（1）By testing the growth curve of Bacillus pasteurii,the best OD₆₀₀ value as the dominant grouting strain is between 0.8～1.2,and the best number of days for grouting is about 12 days.（2）By comparing the pore changes after grouting reinforcement with or without seepage field action,it can be concluded that the MICP technology rein-forcement under the action of the seepage field will make the overall pore volume of the tailings sample smaller,and the pores will increase locally.Found by scanning electron microscopy,migration of seepage flow field,such that fine particles will flow with the water sample migration,causing coarser particles leave the sample backbone,such that the sample becomes large pores,reducing crystallization of calcium car-bonate site.（3）The cohesive force of the specimen after microbial grouting reinforcement under the action of the seepage field is reduced by 17.3%compared with the cohesion force without the action of the seepage field,and the internal friction angle drops by3.89°.The overall calcium carbonate content generated is less than that of the carbon-ic acid generated without the action of the seepage field.Calcium content.When the hydraulic slope is 1,the content distribution of calcium carbonate after microbial grouting reinforcement under the action of seepage field conforms to the linear fitting equation y=x-1.45,（x represents distance,y represents the proportion of calcium car-bonate content）.（4）Through numerical simulation calculation,the safety factor of the slope without MICP technology reinforcement without seepage is 1.3626,the safety factor after reinforcement is 1.68675,and the safety factor is increased by 27.1%.The sta-bility coefficient of the slope without MICP technology reinforcement under the ac-tion of seepage is 1.23529,which is slightly lower than that of the unreinforced con-dition under the action of no seepage field.After reinforcement,the slope stability factor increased to 1.67891,and the safety factor increased by 26.4%.The working conditions of the tailings dam under the action of the seepage field,after the MICP technology reinforcement,can effectively reduce the flow velocity of the seepage field in the dam,and the maximum flow velocity is reduced by 54.4%.