为了使现代城市更有效率，具有更多功能，全球各大城市愈发关注地下空间的利用问题。然而，由于在大城市很多地下建筑物（如重要市政管线）已经开发，要开发新的地下空间，就要求更好更有效地利用浅层和深层的地下空间。因此，在尽量不影响地下水自然环境及邻近的地下或地上建筑物的前提下，开发适用于深埋和/或大断面建筑物的施工技术显得尤为重要。此外，由于多数亚洲国家大城市的地层由软弱沉积物构成，如黏土、淤泥、砂、砾石层等，且地下水位高；所以，有关现场勘察、设计、安全管理和环境保护监控、地下水处理、土体改良等的新技术都是必需的。根据这些需求，总结了在日本开发的新技术，包括现场勘察与监控技术、隧道及地下工程施工技术、土体改良技术、地下水处理技术与地下径流保持技术等。希望这些技术能够满足各大城市经济高效、环保地开发地下空间的需求。这些新技术不仅对发达国家大城市的地下空开发有用，而且对发展中城市的地下空间开发同样有用。
The utilization of underground space becomes a more important issue in megacities of the world in order to build more functional and advanced cities. However, because a lot of underground structures such as lifelines have already been developed in the megacities, a demand for the new underground development increases for a better efficient utilization of shallow and deep underground space. For this reason, it becomes important to establish the technologies for underground construction that could be applied to large depth and/or the large cross section structure constructions, with little influences on the natural environments of groundwater, the congested structures under or above the ground. Moreover, the geology of megacities in most Asian countries, particularly, consists of soft deposits such as clay, silt, sand and gravel layers with high groundwater table. Therefore, new technologies related to site investigation, design, monitoring for safety management and environmental preservation, groundwater strategy, as well as the soil improvement etc., are necessary. According to these demands, this paper collectively introduces the advanced technologies developed in Japan, including site investigation and monitoring technologies, tunneling and underground construction technologies, soil improvement technologies, groundwater treatments and groundwater flow preservation technologies.It is hoped that these technologies can meet the demands to develop the underground constructions in an economic efficient way with little influence on the environment in each megacity. The sharing of these new technologies would be useful not only for the megacities in the developed countries but also for the cities in their developing.
