An Interval Algorithm Based Method for Testing the Validity of In-situ Stress Measurement Data

Abstract

As a second-order Cartesian tensor, in-situ stress naturally inherits the abstraction and mystery of the mathematical concept of stress tensor. It is difficult to present the in-situ stress measurement data intuitively and judge the validity of the measurement data concisely. It is pointed out that the orthogonality between principal stress vectors is the only criterion to judge the correctness of in-situ stress measurement data. The error algorithm based on interval calculation theory and simple error estimation algorithm are established to measure the degree of deviation from orthogonality between principal stress vectors caused by truncation of in-situ stress azimuth data, which can be used as an effective criterion for the validity of measurement data. In order to visually express the in-situ stress measurement data and to clarify its relationship with the stability of surrounding rock of underground engineering, the all element presentation method integrating data validation, three-dimensional stress state and stress ellipses on characteristic sections is proposed, which can clearly distinguish whether the principal stress vector meets the orthogonality at a glance. At the same time, the anisotropy degree of initial stress state of surrounding rock and the stress evolution path caused by excavation and unloading can be obtained intuitively. Using the all element graphical expression method proposed in this paper can visualize and concretize the abstract concept, and has stronger indication, which is convenient for the application of practical engineering.