基岩冻结壁解冻过程中井壁的受力与变形规律

The traditional double-composite shaft lining is built with freezing sinking in deep pore water-rich rock at a high cost. However, the new single-layer shaft lining built with freezing sinking can reduce the cost significantly, and its wide application can be prospected. The load during the thawing process of frozen wall is critical for the design of the single shaft lining, which is still lack of in-depth study. The reveal of the mechanical law of the shaft lining during this process is the premise for its scientific design. Based on the previous work, firstly, the ice-saturated porous rock is studied through sample testing and the random pore meso numerical simulation. The variation law of mechanical parameters of frozen rock can be obtained with negative temperature, porosity, depth, test patterns and other factors during porous ice warming and melting, which can provide basic data for further study. Secondly, three kinds of models will be set up for the water-thermal-mechanical coupled interaction between shaft lining-thawing frozen wall-surrounding rock, which are the plane strain analytical model based on the theory of multilayer cylinder, the physical simulation model based on the typical and actual engineering condition, and the random pore meso numerical simulation model, respectively. Through the second part, the mechanical, deformed and damage law of shaft lining can be obtained during frozen wall thawing. Finally, the method to determine load value will be proposed from the foregoing study results, and the design theory can be established for the single-layer frozen shaft lining in porous water-rich rock. The achievement of this project will has a significant theoretical and practical value for the development of freezing shaft sinking technology in complex and deep rock.

深厚孔隙富水岩层冻结法凿井中，传统的双层复合井壁造价高昂。新型单层冻结井壁可大幅降低井壁造价，应用前景广。冻结壁解冻过程中井壁受到的荷载是单层井壁的关键荷载，缺乏深入研究。揭示此过程井壁受力规律是科学地设计井壁的前提。在前期工作基础上，首先，针对孔隙饱冰岩石，通过岩样试验和随机孔隙细观数值计算，获得孔隙冰升温和融化过程中冻结岩石的力学参数随负温、孔隙率、埋深、试验模式等因素的变化规律，为后续研究提供基础数据；其次，针对井壁-正融冻结壁-孔隙含水围岩之间的水热力三场耦合相互作用，分别建立基于多层筒理论的平面应变解析分析模型、基于典型原型工程条件的物理模拟模型和贴近实际的随机孔隙细观数值模拟模型，获得冻结壁解冻过程中井壁受力、变形、破坏规律等；最后，根据上述成果提出井壁荷载取值方法，建立孔隙含水基岩中单层冻结井壁设计理论。本项目成果对深厚复杂岩层中冻结法凿井技术的发展有重要理论意义和实用价值。

冻结法凿井中，随着深度的增大，在深厚孔隙富水地层中基岩冻结井壁按照承受全水压进行设计，井壁厚度大，设计不合理，未考虑岩体的自承载能力和岩体与井壁的相互作用，通过本项目研究可为深孔隙含水冻结基岩中单层井壁结构设计提供科学依据。项目实施过程中开展了正融孔隙含水基岩冻结壁—井壁相互作用规律数值计算研究，获得了基岩冻结壁—井壁相互作用在各影响因素下的变化规律。开展了孔隙含水岩层中井壁结构的水力荷载数值计算研究，建立了孔隙介质模型，研究了获得了孔隙含水岩层中结构的水力荷载在各影响因素下的变化规律，提出了井壁设计的建议。进行了孔隙围岩相似材料研制力学参数变化规律研究，获得了稳定可靠的孔隙模拟岩体，并获得了相似岩体的物理力学参数。开展了基于OFDR分布式光纤应变测试技术在模型试验中应变传递特性研究，进行了多种分布式光纤应变传递特性和模型试件的裂缝捕捉技术研究，采用试件试验证实了分布式光纤测试技术应用于混凝土结构应变测试时测试效果好，应用于复杂应变场中测试技术优势更显著。开展了正融孔隙含水基岩冻结壁—井壁相互作用规律物理模拟试验研究，获得了其相互作用规律。进行了孔隙含水基岩中冻结井壁设计理论的研究，使得孔隙含水围岩条件下冻结井壁的设计方法有了一定的进步。本项目成果将为孔隙含水基岩中冻结井壁设计理论的构建提供重要的科学依据，可应用于煤炭、金属、非金属及其他含水围岩条件下的地下结构设计中，应用前景较为广泛。