基于极限分析法的软岩巷道底板极限承载力研究

摘要

One of the main reasons which lead to soft rock roadway to produce floor -heave is that the floor rock produces plastic deformation under the action of the loosen rock.The limit bearing capacity of the floor is the theoretical foundation to judge whether the floor -heave happens or not.This paper builds the maneuvering field that satisfies all conditions of mechanical boundary and the upper bound solution of ultimate bearing capacity of roadway floor,and it is deduced by means of limit analysis upper bound method.On the basis of the yield condition and equations of equilibrium,this paper also builds a statically admissible stress field and the lower solution of ultimate bearing capacity of roadway floor by the lower bound limit analysis.The upper bound solution and the lower solution of ultimate bearing capacity of roadway floor which have been deduced are equal,and then it gets the floor of the exact solution of soft rock roadway limit bearing capacity.%软岩巷道底板岩体在边墙两侧松动围岩的作用下产生塑性变形是软岩巷道产生底鼓现象的主要原因之一，底板极限承载力是判断是否发生底鼓的理论依据。借助极限分析上限法，在软岩巷道底板塑性区域建立满足力学边界条件的机动场，推导出底板极限承载力的上限解公式；运用极限分析下限法，以屈服条件和平衡方程为基础，建立静力场推导出底板极限承载力的下限解公式。所推导出的底板极限承载力上限解、下限解相等，进而得到软岩巷道底板极限承载力精确解。