微生物诱导碳酸钙沉淀填充裂隙岩体渗流规律试验研究

Seepage Law of Fractured Rock Mass Sealed with Microbiologically Induced CaCO Precipitation

利用微生物诱导碳酸钙沉淀(MICP)填充裂隙岩体,采用自主研发的三轴压缩渗流试验装置,进行了不同裂隙宽度、充填率、围压条件下MICP充填裂隙岩体渗流试验,同时测量岩体横波波速。研究结果表明:MICP充填裂隙岩体试样渗透系数受裂隙宽度的影响,也受填充率影响。不同宽度的MICP充填裂隙岩体渗透系数随围压升高呈下降趋势,最高可下降58.03%;当围压较小时,渗透系数下降较快,随着围压增大,渗透系数下降速度逐渐减慢;同一岩性MICP充填裂隙岩体渗透系数随波速增加而减小。MICP充填裂隙岩体渗透系数计算公式可拟合为自然对数横波波速与负指数围压之和形式。研究结果对于MICP充填技术在裂隙岩体注浆应用具有重要意义。

Fractured rock mass was firstly treated by microbiologically-induced calcium carbonate precipitation(MICP),and then taken for the compression seepage tests by using a self-developed triaxial apparatus under the conditions of different fracture width,filling rate and confining pressure,as well as for the measurement of the transverse wave velocity.The experimental results show that the rock samples with MICP-filled fracture has the permeability coefficient dependent on the fracture width and the filling rate.It is found that rock mass with MICP-filled fracture of different width has its permeability coefficient on the decline as the confining pressure increases,maximally falling down by 58.03%.The permeability coefficient decreases rapidly when the confining pressure is small,but turns to fall slowly as the confining pressure increases.The fractured rock mass of the same lithology after MICP treatment has its permeability coefficient decreased with the increasing of wave velocity.The calculation formula for permeability coefficient of the fractured rock mass after MICP treatment can be fitted to the sum of natural logarithmic transvers wave velocity and negative exponential confining pressure.The research results are of great significance for the application of MICP fracture-sealing technology into the grouting of fractured rock mass.