碎屑流地层隧道掌子面灾变行为及围岩稳定性控制研究

Catastrophe behavior of working face，movement and development law of debris flow, stability control of surrounding rock mass are the key scientific issues of tunnel construction in the debris flow strata. With substance composition of debris flow and geological structural features considered, water and rock coupling models of debris mass comprised of cataclasite and granular media are established respectively, the calibration between macro parameters of debris flow and micro parameters of particle flow code is carried out. Based on above, combined with model experiment, the law of gestation, evolution, development and disaster mechanism of debris flow are researched. According to the theory of water and rock coupling, the instability model of tunnel face and the critical safe distance to the tunnel face under the sustainable influence of water are revealed.The preact high-position drainage method concerning stability of tunnel face is formed. Through the research on the relationship between extrusion deformation and stability of tunnel face, a stability criterion for tunnel face is put forward. Giving consideration to the mechanical behavior of surrounding rock having been little researched with respect to the environment of water-bearing rock in the particular stress state of debris flow strata and construction process of drainage, pre-support and excavation centring on advance core of tunnel, the theorem and method about control of state-transformation of surrounding rock under the disaster environment of debris flow are put forward. With the application of grouting and pre-reinforcemant of advance core after the preact high-position drainage for the purpose of improving debris flow strata, a set of key control technique about stability of tunnel face in the debris flow strata is established. Combined with in-site test of multiple sections and experimental system of compound model which can simulate strata,water pressure and support simultaneously, a reasonable support structure system is established. Finally, the transition of the state of surrounding rock from catastrophe to gradual even to steady-state is achieved, then the technique of disaster control and construction of tunnel in the debris flow strata are formed.

掌子面灾变行为、碎屑流运动发展规律、围岩稳定控制是碎屑流隧道修建过程中关键科学问题。从碎屑流物质组成、结构特征入手，建立水-岩耦合作用的碎屑体（碎裂、散体）结构模型，标定碎屑体宏观参数与颗粒离散元细观参数对应关系；结合模拟试验，研究其孕育、演化、发展规律和成灾机理。采用水-岩耦合理论，探明水持续性作用下掌子面失稳模式、临界安全距离；围绕掌子面稳定，形成高位排水工法；研究掌子面挤出变形与稳定性关系，提出掌子面失稳判据。基于碎屑体赋存环境（作用力、富水）、物理力学性态（核心土）与工程作用（排水、预支护、开挖卸荷）相互作用方法，提出碎屑流灾害环境下围岩状态转变控制原理和方法，建立"排水-注浆-核心土预加固"成套掌子面稳定控制关键技术；结合现场多断面及复合体（地层-水压-支护）模型试验，建立碎屑流隧道合理支护结构体系；最终实现围岩状态由灾变到渐变甚至稳定的转变，形成碎屑流隧道灾害控制及修建技术。

掌子面灾变行为、碎屑流运动发展规律、围岩稳定控制是碎屑流隧道修建过程中关键科学问题。从碎屑流物质组成、结构特征入手，建立水—岩耦合作用的碎屑体（碎裂、散体）结构模型，标定碎屑体宏观参数与颗粒离散元细观参数对应关系；结合模拟试验，研究其孕育、演化、发展规律和成灾机理。采用水—岩耦合理论，探明水持续性作用下掌子面失稳模式、临界安全距离；围绕掌子面稳定，形成高位排水工法；研究掌子面挤出变形与稳定性关系，提出掌子面失稳判据。基于碎屑体赋存环境（作用力、富水）、物理力学性态（核心土）与工程作用（排水、预支护、开挖卸荷）相互作用方法，提出碎屑流灾害环境下围岩状态转变控制原理和方法，建立“排水—注浆—核心土预加固”成套掌子面稳定控制关键技术；结合现场多断面及复合体（地层—水压—支护）模型试验，建立碎屑流隧道合理支护结构体系；最终实现围岩状态由灾变到渐变甚至稳定的转变，形成碎屑流隧道灾害控制及修建技术。