Theory and design methods for geotechnically structured permanent support for deep foundation pits

Abstract

Based on an in-depth analysis of the current situation of the project's underground system design, reflecting on the disadvantages of waste, pollution, and carbon emission caused by the separation of geotechnical and structural professions for temporary foundation pit support, and adapting to the requirements of the new development concept, the theory and design method of deep foundation pit geotechnical structured permanent support system is proposed. It clarifies the composition and construction process of the components of the permanent support system and stipulates the design principles of the bearing capacity and normal use limits of the permanent support system. Moreover, the load combinations and calculation contents of the three stages of the foundation pit excavation, construction, and normal use are clarified, suggesting the finite element method and elastic support method applicable to the division boundary of deep and deeper foundation pits and their permanent support structures respectively. The durability analysis of the support components is emphasized, proving that the geotechnical structure is good. The deep foundation pit permanent support structure basement exterior wall is not subject to earth pressure, changing the current situation that the excavation stage support structure and the use stage basement exterior wall bear the earth pressure separately. Twice the building materials resist the earth's pressure. The theory of permanent support structures for deep foundation pits is the basis for the high-quality development of foundation pit engineering in the new development phase. The geotechnical structural design method is the technical support for the change from temporary to permanent foundation pit support.