热-水-力耦合作用下裂隙岩体微生物阻渗机理研究

Water inrush occurs frequently during the excavation of underground space engineering. The fractured rock as water inrush channel is induced in surrounding rock area during the excavation. Microbial induced calcite precipitation (MICP) may be a novel method to treat water inrush as a new technique with low grouting pressure and reducing permeability. But the mechanism of thermo-hydro-mechanic(THM) coupling of MICP in fractured rock, and the one of its permeability barrier are unclear. So the mechanism of THM coupling of MICP is analyzed systematically，a numerical simulation method of microbial permeability barrier in fractured rock is developed, and considering THM coupling the mechanism of MICP in fractured rock and the influence of MICP on the variation of fracture permeability are studied experimentally and numerically, thus the mechanism of microbial permeability barrier in fractured rock under THM coupling is presented. The results of this project can provide a theoretical basis of microorganism technique to treating water inrush, and can facilitate its application on treatment of water inrush in underground space engineering.

突水是一种常见的地下空间工程地质灾害。地下空间工程围岩随开挖卸载破坏形成裂隙岩体，成为突水通道。微生物诱导碳酸钙沉淀注浆压力小，能有效降低裂隙岩体渗透性能，可望成为一种新的突水治理方法。目前，微生物诱导碳酸钙沉淀影响下裂隙岩体热-水-力耦合作用及其阻渗机理尚不清楚。本项目将系统研究考虑微生物影响的裂隙岩体热-水-力耦合作用机制，研究裂隙岩体微生物阻渗机理数值模拟方法，试验和数值模拟研究岩体裂隙中微生物诱导碳酸钙沉淀机理，探究热-水-力耦合作用下微生物诱导碳酸钙沉淀对裂隙岩体渗流变化的影响规律，揭示热-水-力耦合作用裂隙岩体微生物阻渗机理。本项目可为微生物工程技术治理突水提供理论基础，促进其在地下空间工程突水治理中应用与发展。

本项目对裂隙岩体MICP注浆阻渗机理进行了广泛和较为深入的试验研究和数值模拟研究，研究表明：MICP可以有效的降低裂隙岩体渗透系数，考虑围压作用下可以降低4个数量级。MICP阻渗效果可以通过横波波速、EIS特性、围压和裂隙宽度等参数进行表征，具有较高的精度。MICP产物不均匀的分布在裂隙岩体结构面，其在裂隙中阻渗路径形成具有一定随机性。二次开发了LBM-PFC数值模拟方法，较好的从理论上揭示了裂隙岩体MICP阻渗机理和阻渗失效机理。本项目研究对进一步研究裂隙岩体MICP阻渗特性以及MICP充填裂隙岩体力学性能具有重要的理论价值，也为其工程应用提供了较好的理论基础。