A large amount of earth works are necessary to obtain flat land for airport construction in mountainous areas. To conduct the earth works efficiently, construction method, especially compaction method suitable for in-situ soil has to be deployed. Mechanism of in-situ soil compaction has not been made clear until now, so the compaction method has been selected based on compaction test on site. This process is not only costly but also time-comsuming.
　As the first step to understand the in-situ soil compaction process, an in-situ compaction reproductive apparatus has been developed. The maximum size of specimen used in this is 90cm wide, 130cm long and 90cm thick. Three kinds of roller, namely tire rolley, macadam roller and vibratory roller can be used. Laboratorycomapction tests using this apparatus have been compared with in-situ compaction test at Shonai Airport. Judging from some compaction tests, the validity of this apparatus can be clarified.