围岩-支护作用机制评述及其流变变形机制概念模型的建立与分析

REVIEW OF INTERACTION MECHANISM BETWEEN SURROUNDING ROCK AND SUPPORT AND ANALYSIS OF CONCEPTUAL MODEL OF RHEOLOGICAL DEFORMATION MECHANISM

岩石地下工程支护理论的核心问题是围岩-支护相互作用机制。首先,分析卡斯特纳方程和围岩-支护作用机制存在的缺陷和错误,包括:(1)模型对支护反力的产生及其支护时机、加载路径等力学处理不具有工程实际意义。(2)由卡氏方程和弹塑性公式推导的围岩特性曲线在工程实际中不存在,因此也不存在与支护结构的支护特性曲线相交的可能性。(3)将围岩特性曲线和支护特性曲线相交求解围岩-支护相互作用的平衡点存在概念及逻辑上的错误。然后,建立基于流变变形的围岩-支护相互作用机制的概念模型。最后,应用流变机制概念模型对工程实例进行计算,推演围岩与支护的相互作用过程,从理论上证实混凝土结构在一定条件下支护软岩巷道是可以的。提出的流变机制概念模型,既可以对围岩-支护相互作用给出定性解释,也可以应用于岩石地下工程的设计,理论基础可靠,能够应用于工程实践。

The essence of underground rock engineering supporting theory is interaction mechanism between surrounding rock and support. A detailed analysis of defects and errors in Kastner equation and current interaction mechanism is given as follows： （1） mechanical treatment of support reaction in the Kastner model may be flawed in its supporting time and loading path, which can not be used in engineering practice： （2） the ground characteristic curve deduced from Kastner equation doesn＇t exist practically and can not intersect with support reaction line： and （3） the equilibrium point solved by the intersection of ground reaction curve and supporting characteristic curve is wrong conceptionally and logically. Then, the conceptual model of rheological deformation mechanism is established. The calculations of project examples are offered, in which the course of the interaction between surrounding rocks and support is derived. It is proven that the concrete structure can be applied to the supporting structure of the tunnel in soft rock theoretically. The conceptional model of the rheological mechanism referred gives the qualitative explanation for the interaction between surrounding rock and support, and can be applied to the design and calculation in underground rock projects. The theoretical basis of the mechanism model is reliable, and has a bright future in engineering practice.