Applied Research In Anti-floating Engineering Of Underreamed Anchor

Recently, with the rapid development of urban construction, the utilization of underground space has received increasingly more attention. The construction of underground project shows a trend towards deep underground space. With respect to coastal city and area with shallow groundwater surface, where groundwater is abundant, engineering disasters occur frequently due to buoyancy force of ground water, which leads to crack, inclination, collapse of upper structures and rise-up of the whole structure. Therefore, anti-floating technique has been received much more concern in recent years and the study of anti-floating technique has become a significant issue in geotechnical engineering field. Anti-floating pile (rock bolt) technology is considered to be one of the most economic friendly measures for deep foundation pit, and has been widely used for anti-floating projects in recent years. In this study, advantages of anti-floating expansion rock bolt of anti-floating technique is elaborated, which is in favor of the development of anti-floating expansion rock bolt technology.On the base of an overview and analysis of overseas and domestic research status the theory and technology of expansion rock bolt, mechanism of action of anti-floating expansion rock bolt is analyzed and mechanical model, mode of failure, failure mechanism and pre-stretch reinforcing characteristic is investigated. Force bearing characteristic at the end of expansion rock bolt is sufficiently analyzed and compared with normal rock bolt. According to the design basis and requirements of anti-floating expansion rock bolt, design content, calculation method and procedure are analyzed. Combined with jin xiu Ian wan rock bolt project in Jinan, introduction is elaborated about the construction process of high pressure jetting hole expansion and mechanical hole expansion method, construction method and requirement, parameter controlling standard and other key technology content. This study is of value for the application of anti-floating expansion rock bolt technology in similar projects.