孔隙含水稳定岩层中地下工程水害形成机理

As the depth increases, water damage of the underground engineering constructed in stable, water-bearing and porous rock layers is worsening, resulting in significant losses.This kind of water damage is pore water disaster, not previously taken seriously, lack of in-depth study, must be resolved. To reveal the mechanism of its formation is a prerequisite for scientific prevention of the water damage. On the basis of previous works, the water damage of vertical mine shaft in stable, aqueous and porous rock layers as typical, Firstly, in order to provide basic data for next researches, by testing the typical water-bearing porous rock samples and mesoscopic numerical calculations to obtain influences of pore pressure on rock elastic modulus, Poisson's ratio, strength parameters and failure characteristics. Secondly, aiming at the interactions between surrounding rock, high-pressure pore water with shaft lining, mesoscopic numerical model containing randomly distributed pores, large-scale physical simulation models and analytical models will be established to study the deformation, failure and leakage laws of the shaft lining, and the variation of the interaction force between the shaft lining and the aqueous surrounding rock.Finally, based on above study, the formation mechanism of water damage will be revealed, the design and calculation theory for shaft lining in stable rock layers containing high-pressure pore water will be established, and the technical route of this kind of water damage prevention will be put forward. The results of this research for the construction and operation of underground engineering built in stable, aqueous and porous rock formations has important theoretical and practical value.

随着埋深的增大，在孔隙含水稳定岩层中，地下工程的水害日益严重，造成了重大损失。该种水害属于孔隙水水害，以前未受到重视，缺乏深入研究，亟待解决。揭示其形成机理是科学地防治水害的前提。在前期工作的基础上，以孔隙含水稳定岩层中立井井筒的水害为典型，首先，针对典型的孔隙含水岩石，通过岩样试验和细观数值计算，获得孔隙水压对岩石的弹性模量、泊松比、强度参数和破坏特征的影响规律，为后续研究提供基础数据。其次，围绕衬砌-围岩-高压孔隙水间的相互作用，建立随机孔隙细观数值计算模型、大型物理相似模拟试验模型和解析分析模型，研究衬砌的变形规律、破坏出水特征，衬砌与含水围岩间相互作用力的变化规律。最后，在此基础上研究揭示水害的形成机理，建立高孔隙水压稳定岩层中衬砌的计算理论，提出防治该种水害的技术路线。本项目的研究成果对高孔隙水压环境中岩石地下工程的建设与运营有重要理论意义和实用价值。

针对孔隙含水稳定岩层中地下工程结构的水害问题，进行了以下研究。首先，研究了孔隙水压力对岩石力学参数的影响，通过理论解析、数值模拟掌握了孔隙水压力等因素对岩石物理力学参数的影响规律；其次，研究了孔隙水压力作用下井壁结构的等效水力荷载，揭示了孔隙含水稳定岩层中地下结构水力荷载的形成机理—类同于围岩热胀冷缩引起的结构荷载，孔隙水压变化致胀或致缩围岩孔隙，进而引起地下结构荷载变化，并且基于该机理，建立了孔隙含水岩层与地下结构相互作用的力学模型，获得了水力荷载的解析解，掌握了地下结构和围岩物理力学参数和几何参数影响水力荷载的规律，发现了结构和围岩接触面接触状态对水力荷载的影响，在未发生剥离的接触面，水力荷载一般不超过2倍围岩孔隙率的静水压，在发生剥离的接触面，水力荷载数值近似等于静水压力；第三，研究了稳定含水岩层地下结构变形规律和破坏模式，试验发现结构和围岩的局部剥离使得结构变形在竖向和水平方向均呈现较大的不均匀性，成为“破坏弱面”，破裂模式以局部渗水、破裂出水为主；第四，提出了孔隙含水稳定岩层中地下工程设计的合理建议，水力荷载是衬砌设计要考虑的关键因素，衬砌应具有合理的强度和刚度，既要有足够的刚度降低衬砌与围岩发生剥离的风险，同时又要合理降低高压孔隙水的影响；最后，结合工程实践，提出了治理孔隙含水稳定岩层中地下工程孔隙水水害的技术路线。项目资助发表论文5篇，授权发明专利3项。培养博士研究生1名，硕士研究生1名。项目投入经费82万元，支出82万元，各项支出基本与预算相符。