Abstract: Foundation treatment of large-scale refinery is very complex. In view of this condition, in-situ test of vibro-replacement stone pile was carried out. With static cone penetration test dynamic penetration, pile density was detected and saturated sand liquefaction was judged. Based on results of pressuremeter test, standard penetration test and heavy dynamic penetration test, foundation bearing capacity change and soil engineering characteristics change during construction process of vibro-replacement stone piles were analyzed. The bearing capacity of composite foundation was evaluated by static load test of single pile and composition foundation. The results show as follows. Firstly, vibro-replacement stone pile has a compaction effect on the sand soil of pile length range. Engineering characteristics and field uniformity has been improved apparently. Sand liquefaction possibility for pile length range can be eliminated. Secondly, static load test results show that the bearing capacity of composite foundation has reached the design requirement. Thirdly, the compaction effect on clay soil, which is under sand soil layer, is not apparent. And soil strength in some depth range even reduces. Finally, the bearing characteristics will not significantly be affected when no more than 5 m thickness of soft soil interlayer exists 10 m depth below the ground surface.

Key words: petrochemical engineering, soft soil foundation, vibro-replacement stone pile, in-situ test