Improvement of design method of rock-socketed pile based on the enhancement effect of shaft resistance

Abstract

Large diameter rock-socketed piles are usually used to support bridge with long-span or high piers. To research its mechanical properties in mountain area, field loading tests based on distributed fiber sensing technique were performed. The tests results indicate that shaft resistance came into play earlier than tip resistance and the upper load was borne mainly by shaft resistance. When the load-sharing ratio of tip resistance exceeded 10%, the enhancement phenomenon of shaft resistance occurred, which became more and more obvious with the increase of the ratio. The shaft resistance and tip resistance are not independent but interact of each other. The increase of tip resistance can promote the shaft resistance to play its role effectively. According to the field test results, the design method of rock-socketed piles was improved based on the enhancement phenomenon of shaft resistance. The calculation results indicate that the rock-socketed length of pile can be shorten effectively by this method which can obtain considerable economic benefits.