Method for building whole rock uniaxial compression process creep model based on S function

Abstract

The invention discloses a method for building a whole rock uniaxial compression process creep model based on an S function. The method comprises the following steps of 1, carrying out uniaxial compression creep testing on a rock test piece under different axial stresses, thereby obtaining rock creep curves; 2, making a symmetric curve along an angular bisector of a coordinate system for the rock whole-process creep curve with accelerated creep, thereby obtaining an S curve; 3, selecting a Weibull function to describe the S curve; 4, calculating an inverse function for an expression of the Weibull function, and determining a function expression of the whole rock uniaxial compression process creep model; and 5, determining creep model parameters according to a rock uniaxial compression creeptesting result. The creep model built by the method can describe three stages of the whole rock uniaxial compression creep process through the unified function expression, so that the defect that anelement combination model needs to be processed in a segmented manner is overcome; and meanwhile, the model expression is simple in form and convenient to apply.

Description

technical field [0001] The invention belongs to the technical field of rock engineering, and in particular relates to a method for establishing a rock creep model in the whole process of uniaxial compression based on an S-shape function. Background technique [0002] In the research of rock creep model, the element combination model has been widely used because the parameters have clear physical meaning and can directly reflect the complex mechanical properties of rock. The complete creep process of rock usually includes three stages, namely decay creep, steady creep and accelerated creep. In the traditional component combination model, it is usually assumed that the model parameters are fixed and constant, so no matter how the basic components are combined, the whole model can only reflect the attenuation and steady-state creep of rock, but cannot describe the accelerated creep. In order to describe the behavior of accelerated creep, the commonly used method at present is ...

AI Technical Summary

Problems solved by technology

The creep model established based on the above ideas has the following disadvantages: 1) It is necessary to artificially divide the original continuous creep process of the rock into three stages, and use three different functions to describe the creep behavior of the rock in different stages (such as using Kelvin The attenuation creep phase is described by a viscous body, the steady-state creep phase is described by a viscous body, the accelerated creep phase is described by a viscous body deteriorating with time, etc.)

Therefore, the overall creep equation is the superposition of three functions, and cannot be expressed by a unified function

2) The form of the model creep equation is relatively complex and inconvenient to apply

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