Dynamic characteristics of basalt fibre-reinforced polymer cement mortar bolts and its applicability for bolt defect detection

Abstract

Basalt fiber reinforced polymer (BFRP) bolt has the advantages of high tensile strength, low quality and corrosion resistance. This kind of bolt has a potential application prospect in tunnel and underground engineering support. However, there is no effective method for non-destructive testing of anchoring quality of BFRP cement mortar, which restricts the application of this kind of anchor. Based on the propagation principle of stress waves in solids, the feasibility of the impact elastic wave method in detecting the length and compactness of bolts is theoretically demonstrated. Then, numerical simulation and test methods were used to study the propagation characteristics of stress waves in bolts under impact load and its application in the anchorage quality inspection of BFRP bolts. The results show that the elastic wave method can be used to detect the length of BFRP bolts and the detection accuracy meets the engineering requirements. In terms of anchoring compactness of cement mortar, this method can identify the location of defects, but the detection accuracy needs to be further improved. The research results presented in this paper can promote the application of BFRP bolts in tunnel and underground engineering support.