Test Study And Application Of Composite Soil Nail Of Deep Foundation Pit

Exploitation and integrative application for underground space are the theme of city construction in this century. The study for design and new construction of underground engineering including foundation pit, metro, tunnel etc. has become pop and difficult problem with the rapid development of old city rebuilding and municipal works, as well as the increase of high-rise building.Soil nail supporting is broadly used in underground engineering, especially used in foundation pit because of its numerous advantages such as fast construction, economic security and so on. However, the generalization of soil nail is limited by itself applied conditions. Since 1990's, composite soil nail supporting has been gradually used in retaining and protecting for foundation excavation in our country. Practice has showed its economic advantage. But compared with application of composite soil nail, theoretic study for composite soil nail is very laggard, so as to many engineering accidents, which brought biggish economic losses and harmful effect to society, happened because of incomplete design method, absent test study etc. Therefore, study for work mechanism, design method and construction technology of composite soil nail is useful of technically perfection, and also useful of broadly application of this technology.In this paper, author compare with Shenzhen Holiday Plaza Project (be known as firstly deepest foundation pit, deepest excavation depth is 21m), use combinative method for theory guidance, test study, simulation analysis, project application and information feedback, entirely and deeply study prestress anchor cable composite soil nail, and also make a pilot study for deformation of pile anchor composite soil nail.1. Author proceeds with the evolvement course from soil nail to composite soil nail, introduces actual study and development to soil nail and composite soil nail, points out some existent problems about composite soil nail in theoretic study.2. Brief introduces all kinds of composite soil nail supporting structure and their construction technique.3. Lots of entirely situ-test study for prestress anchor cable composite soil nail have been made. According to test results, author analyses deformation characters and its rules of prestress anchor cable composite soil nail supporting and pile anchor composite soil nail supporting, studies work mechanism of prestress anchor cable composite soil nail supporting structure, explores change regularity of inner force of soil...