微生物与氧化镁协同作用胶结钻屑机理研究

Mechanism Study on Synergistic Effect of Microorganisms and Magnesium Oxide on Cementing Drill Cuttings

微生物诱导碳酸钙沉淀(MICP)是一种新型污染土加固修复方法,为钻屑的胶结处理提供了新思路。在分析高活性氧化镁凝胶材料胶结体的基础上,对微生物-氧化镁协同胶结钻屑进行了深入研究,提出了微生物与氧化镁协同胶结钻屑新方法。采用傅里叶变换红外吸收光谱仪、X射线衍射仪和扫描电子显微镜对胶结体进行测试,结果表明:微生物-氧化镁协同作用产物为玫瑰花状水菱镁石(4MgCO_(3)·Mg(OH)_(2)·4H_(2)O)和针状三水碳镁石(MgCO_(3)·3H_2O);产物以致密的碳酸盐网络状结构将松散的颗粒胶结成结构完整的胶结体。对影响胶结体强度的因素分析表明:胶结体的强度发展趋势与微生物浓度、活性氧化镁浓度、养护时间成正相关,与含水量、尿素浓度呈负相关。

Microbial-induced calcium carbonate precipitation(MICP)is a new reinforcement and remediation method for contaminated soil,which also provides a new direction to cement drill cuttings.Based on the analysis of the cemented body of highly active magnesium oxide gel material,an in-depth study on synergistic cementation for drill cuttings by microorganisms and magnesium oxide was conducted,and a new treatment methods for drill cuttings was presented.The speciemens cemented by microorganisms combined with magenesium oxide were tested with FTIRs,XRDs and SEMs,and the results indicated that rosette hydro-magnesite(4MgCO_(3)·Mg(OH)_(2)·4H_(2)O)and acicular nesquehonite(MgCO_(3)·3H_(2)O)were yielded in synergy of microorganism and magnesium oxide.The loose particles were cemented into the well-structured cemented body by the dense carbonate network which was the cementitious mechanism of the synergistic effect of microorganism and magnesium oxide.The analysis of the factors affecting the strength of the cured body showed that the development trend of the strength of the cured body was positively correlated with microbial concentrations,active magnesium oxide concentrations,and curing times,and negatively correlated with the water content and the urea concentration.