EXPERIMENTAL STUDY OF DEFORMATION AND PORE WATER PRESSURE FOR EMBANKMENT ON SOFT SOIL USING RAPID IMPACT COMPACTION

Abstract

This study was conducted to analyze the deformation behavior and increases of pore water pressure on an embankment construction on the clay soil layer which is compacted using the Rapid Impact Compaction (RIC) Method. In this study, an equipment model was used that can simulate the RIC method which was electro-mechanically controlled at frequency of 30-40 blows per minute. The compaction test mold has a diameter of 80 cm and height of 120 cm, tested clay layer has a thickness of 80 cm and the sand-and-gravel embankment has a thickness of 30 cm. The clay layer was attached with pore pressure cell and earth pressure cell. An ultra-sonic sensor and a dial gauge were put on the surface. The compaction process with RIC was carried out up to 300 blows using a 45kg impact mass, falling height of 15 cm, impact base diameter(B) of 30 cm. The results showed the achievement of 90% of maximum vertical deformation on the impact foot occurred at 175 blows and heaving surfaces occurred at a distance of 0.80B from the center of the impact base, while at the 300 blows, the heaving surfaces distance was 0.90B. The analysis showed the generation of excess pore water pressure following the phenomenon of undrained conditions in the cyclic dynamic loading, where there was a very fast increases of pore water pressure at the 55 first of blows of the initial stage of compaction and then the increase rate reduced until reaching the constant line after the 175 blows.