Design Optimization Of Strip Foundation Pit Retaining Structure Under Asymmetric Load

With technology improving and society developing, foundation pit engineering has alsogained great achievements. More and more big and deep foundation pits appear promptly,meanwhile foundation pits of underground syntheses and subway station attract greatattention for their complex design and difficult construction.Subway station foundation pits are always strip with complex surroundings. Recentlyscholars have taken many researches about them from every aspect. But, as to asymmetricload, a common sense is rarely researched by experts. This article gains the displacement ofdeep soil, steel shotcrete’s axial force, soil pressure, pile top displacement and so on byanglicizing and processing the data gained from monitoring in subway station foundation pitof capital cultural and arctic center in Jinan. The key analyze is about steel shotcrete’s axialforce. Give a simple explain about the internal cause considering the work condition.Establish two different3D models to compare their inner force and deformation by usingPlaxis. Then draw some simple conclusions. At last, do a optimized design of steel shoetrees.Two economic plans are given.The conclusion:1. Overexcavation and later support will lead to huge soil stressrelease, huge displacement and high increase on previous ones.2. Among many factors, thework conditions influence most. The influential factor of three shoetrees are0.35,、0.24、0.17.3.The biggest displacement of support pile is35mm bigger under asymmetric load. Thebending moment is bigger and the inflection point is upper.4. The distribution law of steelshotcrete’s axial force is the same with those former ones, but each reduces10%~30%.5. Thesupporting role of shoetree is weaker under asymmetric load, and its displacement becomesmaller.6. Through optimized design we reach that: the outer displacement is controlled byimprovement of structure stiffness or soil reinforcement; changing shotcrete’s location andquantity leads to a30%release cost.At last, some useful design suggestions of this kind foundation pits are given.