To improve the performance of a bored steel H pile installed in a prebored hole, a grouted base is made around the base of the pile. The structural capacity of the pile with a grouted base was studied by two series of model loading tests. Failure mechanism was observed, which depended upon the geometry of the grouted base. The failure occurs in which the grouted base is thin, less than twice the pile diameter. Structural capacity increases with increasing the thickness of grouted base. Field tests were caried out, boring test, excavated measurement and loading tests. The effectiveness of the method and large ultimate bearing capacity were proved by the tests.
