ABSTRACT:

This paper describes full-scale test on five large bored piles with grouted end in Fuzhou, southeast coast of China. Test program included site investigation, pile installation and end grouting. The piles were instrumented with strain gages and load cells to identify load distribution in the piles. The piles were tested under a vertical load of 9 MN that is limit load for shaft material. Test results showed that end grouting improves load-settlement performance of bored pile. The ultimate load of the test pile was estimated to be higher than the maximum test load. Pile shaft resistance carried the most portion of the applied load. Less than 10% of the applied load transferred to the end. End grouting significantly increases the shaft resistance near the pile end.

INTRODUCTION

Fuzhou is located on the southeast coast of China. Most areas of subgrade in this district are soft soil of resent fluvio-maring sediment. Large diameter bored piles are commonly used as foundation for multistory buildings in Fuzhou. These piles are normally founded on bedrock in order to guarantee high end bearing capacity and low settlement under working load. The rock socketed piles are mostly long shaft piles because bedrock lies deeply under the ground in Fuzhou. Such piles are not only difficult but also cost to be constructed. Furthermore, case studies showed that load-settlement behavior of such piles was often not satisfied the requirement of heavily loaded building. Research on load transfer behavior of bored piles in Fuzhou indicated those end faults sharply decrease the total bearing capacity of the piles. Grouting was always suggested to treat the end faults and to improve the end condition of large bored piles. This paper describes a case study of large bored pile with grouted end for an actual project in Fuzhou.

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