Method for Defining the Distribution of Triaxial Stress States in Underground Structures

摘要

A method for defining the distribution of triaxial stress states in three-dimensional underground structures is described. The reason for interest in the degree of triaxiality is that one of the ways to evaluate how well a particular constitutive model correctly predicts stress states in the underground structure is by comparison with laboratory results, i.e. laboratory tests should be undertaken which simulate as closely as possible the dominant triaxial stress paths and end states the underground structure is likely to encounter during service. Thus, the dominant triaxial states of a particular application must be defined in order to permit constitutive model evaluation. The method is illustrated by examination of the solution from a preliminary stress analysis of a complex drift configuration at the bottom of a deep shaft in a proposed underground testing facility. In this example the dominant triaxial states depend very strongly on the assumed in situ stress state and are quite distinct from stress states normally considered in laboratory testing. A method of showing the distribution of stress states is shown, as well as discussion of how this information can be used to plan a constitutive model development program. (ERA citation 09:025113)