Analysis of measuring existing stresses in concrete structure by hole drilling core surface strain gauge method

摘要

The hole drilling core surface strain gauge method for measuring existing stresses in concretenstructures has been discussed. First, the release detection process of hole drilling has beennsimulated using nonlinear three-dimensional finite element method, based on the concretendamaged plasticity theory. The technique of element birth and death has been used to simulatenthe drilling process. Laws of stress measurement described by stress release rates and h/dn(where h is the depth of hole and d is its diameter) have been studied. Second, experiments havenbeen carried out to prove the efficiency of this method. Compared with numerical results, thenexperimental stress release rates are obviously lower than simulation results. Finally, normalnstresses have been loaded on the cylindrical surface of the concrete core to simulate theninfluence of core bit swaying, and the results of modified numerical data analysis have beennobtained. The results indicate that the rules of stress measurement by hole drilling release whichnhave been represented by stress release rates and h/d, are widely used.