Numerical Analysis And Applied Research Of Soil-pile Anchor Composite Supporting

Soil nailing technology has been widely applied to the deep excavation project. With the advantage of quick, easy, economical and reliable on construction.However, ordinary soil nailing wall cannot meet the requirement of stability and deformation control,especially for the deep pit,or poor self-stabilizing soil engineering, such as those containing soft soil or sand layer; or deformation control with high requirements, as there is traffic surrounding roads, pipelines and other buildings. So in recent years, a more suitable form of composite soil nailing appears, for example, the combination of soil nail wall and Bolt (Cable). However, the theoretical research of the mechanism and influence factors on composite soil nailing technology are still far from the engineering practice by far.In this paper, we use the method of finite element analysis method to analyze and study the compound soil nailing technique which combines the soil nailing and pile-anchor.The study includes:(1)From the point of the calculate method of finite element nonlinear problems, the constitutive model of soil, the calculation principle of model and unit type selection, we can build the two-dimensional soil nails-pile composite anchor shoring models of finite element in the ABAQUS finite element analysis software.(2)To verify the advantages of the soil nails-anchor piles complex supporting technique, we compare the soil nails-anchor piles complex supporting technique and the method of pure soil nailing, and we use composite support pattern of a deep excavation in Huainan City as an example, and using ABAQUS finite element analysis software to simulate and analyze the two supporting situations in order to get the results of the axial force of soil nails and bolts, and the displacement of the pit. Through specific analyzes, we study the pit horizontal displacement, the axial force change of soil nailing and anchor with the gradual excavation pit. At the same time, we collect the monitoring data of the instances, and then comparing the simulation results and to verify the correct and rational of the model.(3)Based on the simulation results, we make deeper analysis of the two design parameters (the dip of soil nails and the size of the bolts prestress) which has the influence to the soil nails-anchor piles complex supporting technique. In addition, we also make a preliminary study of the mechanism of compound soil nailing. The results of numerical simulations show that the soil nailing vary the distribution patterns of compound soil nailing support system in the stress field and displacement field. Given the combined effect of soil nailing and pile anchors, deformation of the pit has been effectively controlled, and the stability of the pit has a marked difference. From a practical point of many engineering applications, composite soil nailing manner is far superior to the pure soil nailing. The advantage of the composite soil nailing manner that it can adapt to complex geological environment and meets the stringent distortion requirements of deep excavation or slope engineering is unmatched by the pure soil nailing manner.Results of this study lies in its ability to deeper understand the mechanisms of composite soil nailing, and it has a good reference in practical engineering of the composite soil nailing.