Mechanical Characterization of Anchor under Uniaxial Compression Loading Conditions

Abstract

Bolt reinforcement technology plays an important role in supporting the construction of many engineering fields, and the uniaxial loading characteristics and behavior tests of anchors have great significance to the research and application of anchors. Therefore, four anchor specimens GA ∼ GD were fabricated and tested to explore the macro and microbehavior characteristics of anchors under uniaxial compression. The stress-strain curves for GA ∼ GC specimens under uniaxial compression were analyzed. The stress-strain curve, elastic strain and creep strain, the failure results, and electrochemical impedance spectroscopy of specimen GD under multistage loading were investigated. The results showed a series of behavior characteristics of anchor under uniaxial compression. Under uniaxial compression, the shapes of stress-strain curves of three specimens GA ∼ GC were similar, and they had experienced four different stages from stage I to stage IV, respectively. After calculating the uniaxial compressive strength of the three specimens, the average uniaxial compressive strength of these specimens was $\overline{{\sigma }_c}$  = 8.31 MPa. The stress-strain curve of the specimen GD was obtained by a multi-stage loading test. The total strain of the specimen consisted of elastic strain and creep strain. In the whole process of loading, the proportion of elastic strain was greater than that of creep strain, and the proportion range of elastic strain was 51.90% ∼ 55.82%. Seven electrochemical impedance spectrum curves of the specimen GD under multi-stage compression load were obtained. The dispersion and concentration of Nyquist curves were affected by different loading levels; the higher the loading level, the more dispersed the Nyquist curve is. In the measured Bode diagram, compared with the previous six measurements, the variation laws of impedance value and phase angle measured at the seventh time in the failure stage of the specimen were quite different. The above research and conclusions can provide some reference for the test theory and engineering application of anchors.