Backfill mining technology is the practice of returning waste materials underground for both disposal and geotechnical stability,however,a challenge with current technologies is that they commonly require cement-based binders which have a relatively high environmental impact.Finding alternatives to cement-based binders can improve environmental performance and this paper proposes microbial grouted backfill(MGB)as a potential solution.In this paper,the effects of the cementation solution con-centration(CSC),volume ratio of bacterial solution to cementation solution(VRBC),particle sizes of the aggregates,and the number of grouting batches on the mechanical properties of MGB are studied.The experimental results show that MGB strength increased,up to a peak value,as CSC was increased,before decreasing as CSC was increased further.The results also show that MGB strength increased,up to a peak value,as VRBC decreased,before decreasing as the VRBC was decreased further.The peak strength was achieved at a CSC of 2 mol/L and a VRBC of 1:9.The strength of the MGB also increased as the number of grouting batches increased.Graded MGB samples showed the highest UCS,25.12 MPa,at particle sizes of 0.2 to 0.8 mm,while full(non-graded)MGB samples displayed mean UCS values ranging from 1.56 MPa when the maximum particle size was 0.2 mm,up to 13 MPa when the maximum particle size was 1.2 mm.MGB samples are consolidated by the calcium carbonate that is precipitated during micro-bial metabolism,and the strength of MGB increases linearly as calcium carbonate content increases.The calcium carbonate minerals produced in MGB materials are primarily calcite,with secondary amounts of vaterite.

Xuejie Deng;Yu Li;Fei Wang;Xiaoming Shi;Yinchao Yang;Xichen Xu;Yanli Huang;Benjamin de Wit

School of Energy and Mining Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Kailuan(Group)Limited Liability Corporation,Tangshan 063018,China;Department of Civil Engineering Tsinghua University,Beijing 100084,China;School of Mining and Geology Engineering,Xinjiang Institute of Engineering,Urumqi 830023,China;Norman B.Keevil Institute of Mining Engineering,University of British Columbia,Vancouver V6T 1Z4,Canada

矿业科学技术学报（英文版）

[1]Xuejie Deng;Yu Li;Fei Wang;Xiaoming Shi;Yinchao Yang;Xichen Xu;Yanli Huang;Benjamin de Wit-.Experimental study on the mechanical properties and consolidation mechanism of microbial grouted backfill)[J].矿业科学技术学报（英文版）,2022(02):271-282

VRBC,vaterite

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