Compressive and Uplift Static Load Tests of Shaft and Base Grouted Concrete Bored Piles

This paper provides an investigation of shaft and base grouted concrete pile behavior by conducting vertical compressive and uplift static load tests (SLTs) in Jinan, China. Three concrete piles were tested by compressive SLTs. Two of these piles were applied with shaft and base grouting, and base grouting technology respectively, and the third was applied without any grouting. Two uplift SLTs were carried out on one shaft and base grouted pile, and one pile without grouting. Traditional methods which include Load-settlement curvatures (L-s), Settlement-log time curvatures (s-lgt) and Time-log Load curvatures (t-lgQ) analysis were provided to check if the bored piles reached the design requirement. In addition, an interpretation of the test results from Double-tangent, DeBeer's, and Chin's methods (for compressive SLTs) and Mazurkiewicz's method (for uplift SLTs) were provided for determining the ultimate pile capacity where piles experienced non-plunging failure. Results from the five SLTs program indicates that the Double-tangent and DeBeer's test results are close to each other whereas Chin's method overestimates the pile capacity; the base and shaft grouting pile and base grouting pile (compressive load) increases 9.82% and 2.89% of its capacity, respectively. Compared to the ultimate uplift SLTs, there is a 15.7% increment of pile capacity after using base and shaft grouting technology.