The Calculation And Analysis Of Deformation Of Soil Nailing Retaining Structure Based On The Incremental Method

Soil nailing technology is an in situ soil reinforced flexible retaining technology which developed in the seventies of last century. Since soil nail wall appeared, it has been widely applied by the virtue of economy, reliability, convenience of the construction and so on. But the current research on working mechanism and characteristics of soil nail wall does not meet the requirements in engineering design and site construction. For example, soil nail wall is a passive method of reinforcing soil, the soil nail works only in the premise of soil deformation; meanwhile the larger horizontal and vertical deformation is unfavorable for slope stability. But the calculations of deformation of the soil nail wall has not yet recognized a simple and reliable method. and the limit equilibrium analysis method which commonly used in soil nail wall design can't calculate the deformation of structure. Based on previous work, this paper puts forward the increment calculation method of deformation of soil nail wall, and using the method discusses the affected factors and the characteristics of deformation of soil nail wall, the main work can be summarized as follows:1.Firstly, calculates the axial force of soil nail wall which considers the effect of construction process, and assume that layer of soil nail wall bears a certain proportion of active earth pressure for the axial force's distribution along the length of soil nails, derives soil nail wall's horizontal displacement at arbitrary position at the axial force. 2.Based on research results of the soil nail pullout test and the mechanism of soil nail pullout, calculates the relative displacement of soil nail and soil in stability areas which caused by shear stress on the contact interface of nail and soil in active area, and adds it with the horizontal displacement which caused by the axial force, obtains the calculating formulas of soil nail wall's displacement and wall side's deformation at arbitrary position along soil nail's axis in initiative area. 3.By comparing with the data of full scale test-site which is representative and has comprehensive data, discusses the difference and connection of the results of the measured data and the calculating formulas, verifies the reliability of calculation method . 4.by using this calculation method compares the influence of deformation in different layout of soil nails, sums up the distribution of deformation and displacement in soil nailing structure.In addition, this paper also simulates the test of soil nail pullout, and obtains the shear deformation coefficient in different soil by the numerical analysis.