Study on Bearing Capacity of Bored Cast-in-Situ Piles by Post Pressure Grouting

Bearing capacity of bored cast-in-situ piles by post pressure grouting can be effectively improved through the grout pipes placed within the piles when concrete is 10–20 days old. Based on tests for seven grouted piles respectively cast in the bearing layers of sand and clay, this paper summarized the process of pressure grouting and investigated in-situ tests of these grouted piles. The principles of controlling the maximum of grouting pressure and the volume of grout injected were also presented in this paper. The interactions between improved skin friction and end resistance of grouted piles were studied. All piles by pressure post-grouting proved completely satisfactory in performance of bearing capacity even when the ultimate load is up to twice or more. The results show that post pressure grouting is an effective method to improve bearing capacity of ordinary bored cast-in-situ piles.