Evolution of support concept and design method of deep foundation pit

Abstract

Based on more than 30 years of construction practice in China, this paper analyzes the advantages and disadvantages of the existing deep foundation pit supporting concepts of “temporary” and “combination with the main structure”, and put forward the “permanent” concept to promote the high-quality development of foundation pit engineering. Combined with a foundation pit project in Jinan, the paper demonstrated the progressive lifting of the three concepts and the calculation content of the corresponding supporting structure, and defined the design methods of “geotechnical method of structure “ and “structural method of geotechnical” that adapted to the concepts of “combination with the main structure” and “permanence”; this paper focused on the analysis of composite soil nailing wall combined with anti-floating anchor, and the durability of anti-floating anchor in the permanent support structure composed of anti-floating anchor, extended support and horizontal floor, and explained the evolution direction of the deep foundation pit support concept and the corresponding content of design improvement. It had guiding value for arousing the reflection and awakening of the geotechnical and structural design management system, promoting the reform of foundation pit and foundation design theory and method, and promoting the practice of “new development concept” in foundation pit engineering.