摘要
微生物诱导碳酸钙沉积技术(microbially induced calcite precipitation,MICP)在土体加固中应用广泛,但在岩体封堵领域的研究成果还不多见。为了研究岩石节理MICP封堵机制,以透明树脂模拟粗糙岩石节理试件为研究对象,考虑MICP反应影响因素,开展了6种不同工况下的岩石节理MICP封堵室内试验,得到了MICP封堵过程中岩石节理导水系数和水力隙宽变化规律以及相应的碳酸钙时空分布图像。试验结果表明:MICP封堵过程中岩石节理水力隙宽随灌注轮次大致呈线性减小趋势,且水力隙宽减小速率与岩石节理中碳酸钙分布情况密切相关,而MICP反应过程中碳酸钙分布又受灌注速率、固定液、菌液和反应液灌注时长、静置时长等因素影响;6种工况中灌注速率较大、先灌注菌液和固定液静置一段时间再灌注菌液和反应液、灌注和静置时间最长的工况4封堵效率和效果最佳,在仅灌注2轮的情况下可将岩石节理导水系数由40.51×10^(-6)m^(2)/s减小至0.52×10^(-6)m^(2)/s,降幅达98.72%,对应的水力隙宽值由0.367 mm减小至0.086 mm,降幅达76.6%;通过观测岩石节理试件上、下表面的碳酸钙沉积情况,发现岩石节理中MICP反应产生的碳酸钙在较短时间内就可以形成一定胶结强度,在封堵岩石节理减小其渗透性的同时,还有改善其力学性能的潜力。
Microbially induced calcite precipitation(MICP)has been widely applied for soil reinforcement,but its applications in rock mass permeability reduction have been rarely reported.To explore the plugging mechanism of rock joints using MICP,artificial rock joint specimens made of transparent resin were prepared,and laboratory MICP plugging experiments under six various conditions considering MICP reaction influence factors were performed.Through the plugging experiments,evolution laws of rock joint transmissivity and hydraulic aperture,accompanied with corresponding CaCO3 distribution images,during plugging processes were obtained.The experimental results showed that the hydraulic aperture of rock joint approximately decreases linearly with grouting cycles during MICP plugging process,and the decreasing rate is closely related to the CaCO3 distribution that is significantly affected by grouting rate,injection time of fixation,bacterial,and reaction solutions,and standing time.Among the six experimental conditions,both the plugging efficiency and effect are optimal under the fourth experimental condition,where the grouting rate is high and the grouting and standing time is the longest.After only two grouting cycles under the fourth experimental condition,the rock joint transmissivity decreases from 40.51×10^(-6)m^(2)/s to 0.52×10^(-6)m^(2)/s with a decrease rate of 98.72%,and the hydraulic aperture decreases from 0.367 mm to 0.086 mm with a decrease rate of 76.6%.Furthermore,the CaCO3 distribution on the upper and lower surfaces of rock joint specimens were observed,and CaCO3 in rock joints produced by MICP reaction was found to bring cementation strength in a short time,which helps improve mechanical properties of rock joints while reducing rock joint permeability.
作者
肖维民
林馨
钟建敏
李双
朱占元
XIAO Wei-min;LIN Xin;ZHONG Jian-min;LI Shuang;ZHU Zhan-yuan(School of Civil Engineering,Sichuan Agricultural University,Dujiangyan,Sichuan 611830,China;Sichuan Higher Education Engineering Research Center for Disaster Prevention and Mitigation of Village Construction,Sichuan Agricultural University,Dujiangyan,Sichuan 611830,China;Jiangxi Youse Construction(Group)Co.,Ltd.,Nanchang,Jiangxi 330038,China;School of Civil and Hydraulic Engineering,Xichang University,Xichang,Sichuan 615000,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2023年第10期2798-2808,共11页
Rock and Soil Mechanics
基金
国家自然科学基金(No.41877195)。
关键词
岩石力学
岩石节理
微生物诱导碳酸钙沉积
导水系数
水力隙宽
rock mechanics
rock joint
microbially induced calcite precipitation
transmissivity
hydraulic aperture
