Study on Development of the Pile Penetration Test System Based on Press-In Construction Data

In the Press-in Method, the piling technology, the piling machine jacks a pile into the ground by a static force using the reaction force derived from the previously installed piles. This technique allows the piles to be installed with less noise and vibration, and in addition saves the room required for the piling work, with the small hydraulic piling machinery and its construction system using no temporary works. Since this piling method enables the piles to be installed without excessively disturbing the soil around the pile, it is possible to obtain information about the ground conditions through monitoring the jacking force during installation and extraction. This feature of the Press-in Method suggests the possibility of utilizing the piles as a tool for grasping the ground conditions. Accordingly, the concept of PPT, Pile Penetration Test, is induced, and this paper introduces the PPT system by providing a clear explanation of it and arranging the present situation and awaiting solutions to develop the system. The PPT system is composed of four aspects; press-in construction site, PPT as a decision making tool for piling conditions, PPT as a tool for quality control of piles, and PPT as a subsurface investigation technique. Among these four aspects, ‘press-in construction site’ is essential to this system, for it functions in the system as the source of the PPT data. The other three aspects are all related to the interpretation of the obtained PPT data, and are expected to be of practical use both in construction sites and in geotechnical academic fields. These four aspects of the PPT system suggests as many research phases, which are discussed in detail in this paper. The system is eventually expected to enhance the benefits of construction works and contribute to producing more validity and accountability of the construction project, on the ground of its advantage of obtaining, supplementing and renovating the subsurface information in every press-in construction site all over the world