Optimization design of microbial solidified tailings sand grouting method

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), May.2025, Vol.48 No.5: 701-707

DOI: 10.3969/j.issn.1003-5060.2025.05.019

Authors

CHEN Xiaobo $ ^{1} $, ZHA Fusheng $ ^{1} $, KANG Bo $ ^{1} $, LIU Zhenghong $ ^{2} $

(1. School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China; 2. Shaanxi Key Laboratory for the Property and Treatment of Special Soil and Rock, Xi'an 710043, China)

Abstract and Keywords

Abstract: Microbial grouting reinforcement technology is a newly developed soil reinforcement method in recent years, which has excellent effects on the reinforcement of tailings ponds and greatly reduces the risk of tailings dam failure. Due to uneven grouting, the development of this technology in practical applications is relatively slow. At present, the commonly used methods for microbial reinforcement technology in the laboratory are unidirectional grouting and bidirectional grouting, both of which have the problem of uneven solidification. To improve the uniformity of microbial reinforcement of soil, this paper proposes a cross bidirectional grouting method while controlling the grouting rate. Cross grouting allows bacterial liquid and cementitious liquid to enter the soil from both ends of the biological column, solidifying the middle part of the biological column. Bidirectional grouting allows bacterial liquid and cementitious liquid to enter the soil from the same end of the biological column, solidifying both ends of the biological column. It was shown that under the same grouting conditions, the unconfined compressive strength of specimens prepared by the cross bidirectional grouting method increased by 329 kPa compared to that of specimens prepared by the bidirectional grouting method, and the calcium carbonate mass fraction in the middle part of the sand column increased from 18.98% to 22.08%. During the cross bidirectional grouting process, the unconfined compressive strength of the sand column reached a maximum value of 1211 kPa at the injection rates of 1.2 mL/min for bacterial liquid and 1.4 mL/min for cementitious liquid, respectively. At the same time, the calcium carbonate mass fraction in the middle part of the sand column increased by 2.18% to 1.85%, and the calcium carbonate mass fraction in the middle part of the sediment was reduced by 1.52% to 1.38%. These results indicate that the cross bidirectional grouting method can effectively improve the performance of microbial reinforcement in the reinforcement of tailings ponds and greatly reduce the risk of tailings dam failure. bonate mass fraction in the middle part of the sand column also increased to 24.31%.

Keywords: microbially induced calcite precipitation (MICP); tailings sand; cross grouting; bidirectional grouting; unconfined compressive strength; calcium carbonate mass fraction

作者信息

陈晓波 $ ^{1} $，查甫生 $ ^{1} $，康博 $ ^{1} $，刘争宏 $ ^{2} $

(1. 合肥工业大学资源与环境工程学院，安徽合肥 230009；2. 陕西省特殊岩土性质与处理重点实验室，陕西西安 710043)

摘要和关键词

摘要: 微生物注浆加固技术是近些年兴起的一项土体加固方法,对尾矿库的加固有着极佳的效果,可有效降低尾矿库溃坝的风险。由于注浆不均匀导致该技术在实际应用中发展较为缓慢。目前微生物加固技术在实验室内常用的方法有单向注浆和双向注浆,两者均存在固化不均匀的问题。为提高微生物加固土体的均匀性,文章提出交叉-双向注浆的方法,同时控制注浆速率;交叉注浆使细菌菌液和胶结液分别从生物柱两端进入土体中,固化生物柱中间部位;双向注浆使细菌菌液和胶结液从生物柱同一端进入土体中,固化生物柱两端。研究表明:同等注浆条件下,交叉-双向注浆法较双向注浆法制备的试样无侧限抗压强度提高了329 kPa,将砂柱中间部位碳酸钙质量分数由18.98%提高到22.08%;交叉-双向注浆过程中在菌液和胶结液注入速率分别为1.2、1.4 mL/min时,砂柱无侧限抗压强度达到最大值1211 kPa,同时砂柱中间部位碳酸钙质量分数也提高到了24.31%。

关键词: 微生物诱导碳酸钙沉淀(MICP)；尾矿砂；交叉注浆；双向注浆；无侧限抗压强度；碳酸钙质量分数

Funding

国家自然科学基金资助项目（42030710）

合肥工业大学学报(自然科学版)

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