Axial Resistance of Bored Piles Socketed into Soft Rock

Three fully-instrumented full-scale static load tests were conducted on three 0.8-m-diameter bored piles socketed at 3.2 m deep into argillaceous siltstone (1.6 and 1.6 deep into strong and medium decomposed siltstones, respectively) in Qingdao, China. About 50% of head load was transmitted and supported by base resistance at the end of the tests. Totally 53 test piles socketed into soft rock with unconfined compressive strength less than 20 MPa in Qingdao were reviewed. The measured side resistance along shaft socked into rock was compared with prediction using empirical methods in literatures based on database from Qingdao projects.