Experimental study on the influence of freeze-thaw cycles on the anchoring performance of GFRP anchor

In view of the failure of rock anchors in spring thawing periods of seasonal freezing areas, this paper aims to investigate the anchorage ability of GFRP anchors under the action of freeze-thaw cycles.Through designing the physical model, loading tests were carried out on the test blocks experiencing 25, 50, and 75 freeze-thaw cycles.According to the test data and failure phenomena, the variation laws of the stress and bearing capacity of the GFRP bolt after freeze-thaw were analyzed.The results show that the freeze-thaw cycle will lead to a decrease in bonding performance between epoxy resin mortar and concrete. After 25, 50 and 75 cycles, the bearing capacity loss is 38.24%, 42.65% and 52.94%, respectively.The ultimate bearing capacity of the bolt decreases obviously with increasing freeze-thaw cycles. The freeze-thaw cycle accelerates the deterioration of the material properties of the bonding material and the surrounding rock. In the process, the load transfer to the interior is accelerated, leading to a reduction in the stress difference among points on the GFRP bolt, and the stress distribution of the bolt is more uniform than that at room temperature. Meanwhile, the deterioration of the material properties leads to local failure ahead of time, and the overall bearing capacity of the bolt is reduced.The research results can provide suggestions for the engineering application of GFRP anchor