At present,there are few researches on the deterioration of anchorage performance of rock mass with cracks under freeze-thaw cycles.Rock-like materials were used to make specimens of fractured rock mass with different anchoring angles,and freeze-thaw cycle tests were carried out.Pull-out tests were carried out on specimens with 0,15 and 30 freeze-thaw cycles,and the evolution process of pull-out force,failure characteristics and load-slip curves of different freeze-thaw specimens obtained from the tests were studied and analyzed.The results show that:1)There are two failure modes:bolt pull-out and rock mass failure.When the pull-out failure occurs,the pull-out force increases first and then drops sharply until it is close to 0.When the rock mass is broken,the pull-out force increases several times and then decreases.2)The anchorage performance and bearing capacity of pre-stressed anchored fractured rock mass decrease after freeze-thaw action.The 90° anchored specimen is prone to pull out failure after freeze-thaw action,while the 45°anchored specimen's bearing capacity decreases after freeze-thaw damage.3)The ultimate pull-out force of the anchorage sample decreases with the increase of freeze-thaw times,and the corresponding slip amount of the anchor rod also decreases.After 30 freeze-thaw cycles,the ultimate pull-out force of the 90° anchored rock mass decreases by about 62.5%,and that of the 45° anchored rock mass decreases by about 59.3%.
关键词
冻融/锚固裂隙岩体/拉拔试验/锚固性能
Key words
freeze-thaw/anchored fractured rock mass/pull-out test/anchorage performance
维普
万方数据