ANALYSIS OF PRESSURE GROUTING AT PILE TIP OF BORED PILES IN PEBBLE STRATUM AND ITS BEARING CHARACTERISTICS

Based on field dead load test for two supergiant bridges of a expressway project, this paper studied the applicability of the technology of pressure grouting at pile tip to bored piles in pebble stratum, and the bearing characteristics of bored piles after applying this technology. The findings show that the bored piles using pressure grouting at pile tip have good adaptability to strata and can remarkably improve the bearing capability and decrease the settlement of pile foundations, and consequently acquire remarable economic and social benefit. After pressure grouting on pile tip, elasticworking range of piles will be extended and be in favour of pile to bear repeated loads and dynamic loads. At the same time, for bored pile using pressure grouting at pile tip, failure mode of material strength damage is likely to occur and attention should be paid to their design.