Study On Numerical Simulation And Application Of Soil Nailing-Anchor Composite Support In Deep Excavation

As a quick and easy, economical and reliable's excavation techniques, soil nailing has been widely applied in deep excavation works. But the simple technique of soil nailing can not be used for muddy soil and other adverse soil conditions, and strictly control the deformation. So it has developed a form of composite soil nailing in recent years, which is to add anchor(cable) in soil nailing wall. At present, composite soil nailing mechanism and behavior of the theoretical research is far behind the engineering practice. In this paper, use finite element analysis method to research the composite soil nailing technology which is constituted by soil nailing and anchor. The study includes the following components:(1) Based on the soil constitutive model of soil nailing and anchor and their contact with the soil surface model, use finite element software ANSYS to establish soil nailing-anchor composite support's two-dimensional finite element model.(2) Simulation analysis of a deep excavation in Handan city, which is used soil nailing and soil nailing-anchor composite support, to get the soil and anchor axial force and the displacement of foundation under the two supporcases. Through analysis, research the horizontal displacement of the foundation, ground subsidence, foundation uplift, soil nailing and anchor axial force, and their changes with the excavation of the situation. At the same time, compare the theoretical results and the monitoring data, in order to evaluate the correctness and rationality of the finite element model.(3) Depth soil nail inclination's and anchor prestressing force's impact on the soil nailing-anchor composite support system. And study the mechanism of a preliminary of composite soil nailing.Numerical simulation results show that composite soil nailing and soil nailing support system is somewhat different in the stress and displacement field's distribution patterns. Because of the interaction of soil nailing and prestressed anchor, which can effectively control the deformation and improve the stability of foundation. The application of practical engineering show that the composite soil nailing method can adapt to more complex geological environment and demanding deformation of deep excavation and slope works. The results of this study has good reference to further understand the mechanism and guide the engineer application of the composite soil nailing.