Study on large - scale in - situ pressurization test of steel composite support

Abstract

The reinforced concrete support as the horizontal internal support of the foundation pit engineering has the optimal effect in limiting the displacement of the surrounding structure, but the engineering cost is high, and the environmental impact is large when it is removed. In some of the foundation pits that meet the requirements, steel supports are used as internal support, which has the characteristics of economy, efficiency and green environmental protection. The restressed steel composite support is connected by high-strength bolts, which has a high strength and a wide application range than the traditional steel support joints. Through the normal axial compression test, the unconstrained axial compression test and unrestrained eccentric compression test were carried out on the composite support of section steel, the influence of steel composite support on the displacement of retaining structure under different loads is explored, and the deformation performance of steel composite support is also explored. The test shows that the displacement of the retaining structure changes linearly with the applied load, and most of it is elastic deformation, and the displacement of the retaining structure on both sides of the support has obvious side-angle effect; The test applied load far exceeds the total prestress value of the composite support of the steel, and the compression deformation of the composite steel support exhibits elastic deformation; The test results show that the steel composite support has strong adaptive stability and large safety redundancy value.