New Technical Research On Inspection Of Concrete Strength By Expanding Bolt Pullout Method

In this paper, the writer studied a new detecting technique-expanding bolt pullout method by using expanding bolt as bulkhead. Firstly, in the thesis writer studied and gained each test parameter of expanding bolt pullout method, and by using test data, writer regressed and gained the strength-detecting formula of expanding bolt pullout method. At the same time, the compositive strength-detecting formulas of expanding bolt pullout method, rebound method, ultrasonic method were gained. Secondly, writer compared expanding bolt pullout method with them. The comparison indicates that there is very good linear correlation between pullout force of concrete and compressive strength. The thesis compared the formula with the strength-detecting formula of expanding bolt pullout method. Thirdly writer, using linear elastic theory and finite element program (ANSYS ), analyzed expanding bolt pullout test. Fifthly, writer using the modified Mohr-Coulomb failure theory, on the base of curving failure surface, derived a theoretical formula between pullout force and compressive strength. Then the thesis compared the formula with the strength-detecting formula of expanding bolt pullout method. Finally, the thesis analyzed the concrete failure mechanism of expanding bolt pullout method and summarized the influence of it.