ANALYSIS ON THE GLOBAL STABILITY OF SOIL NAILING SUPPORTING STRUCTURE FOR REINFORCEMENT OF SOIL SLOPE

摘要

Soil nailing supporting structure is an effective method used in reinforcement of soil slope.The current design for this structure is carried out based on "Technical Specification for Retaining and Protection of Building Foundation Excavations", but the stability analysis is few discussed,especially the external stability. As a permanent reinforcement measure, engineering and technical personnel must pay full attention to the global stability of soil nailing supporting structure. In this paper, the soil body in slipping zone after reinforcement using soil nailing is regarded as continuous medium. Then the calculation model for internal global safety factor and the search model for the critical slipping surface of soil nailing supporting structure are established respectively by using integration method. Based on the geometrical relationships of parameters, the function relations among the geometrical controlling parameters of slipping surface are derived. The critical slipping surface has been searched and determined by using mesh method. In addition, after the internalstability has been assured, taking the soil slope in certain zone after reinforcement as a gravity wall,the checking models for external stability including anti-slip and antidumping are further founded,and the checking formula are derived. By the analysis of internal stability and external stability, the rational design scheme of soil nailing supporting structure is achieved. Finally, combining an engineering practice, the existed problems in the design of soil nailing supporting structure are discussed, which provides practical experience for the use and development of this kind of supporting structure.