Mechanical Response Of Soil Nailed Wall Under Cyclic Load

Soil Nailing for its convenience construction,low cost and good performance of the support is widely used in foundation pit,slope support and surrounding rock support. A large number of engineering practice,experimental research and theoretical analysis have shown that soil nailing has a good dynamic load performance and the superiority effect of economic and technological. However, as development of economic construction, which lead to increase of traffic load,the impact of traffic load on the deformation of soil nailed slope becomes larger. Both domestic and foreign stability study of soil nailing under dynamic load is rare. In the article, stability of the soil nailed slope under cyclic loading is studied in detail through model test and numerical simulation.Firstly, a Soil Nailing slope model test under cyclic load is set up. A sinusoidal waveform load with three kinds of range 10-30, 30-50, 50-70kN,2Hz load frequency,10000 times, is used to a typical cyclic load. Displacement of concrete panel and settlement of top surface shows obvious cumulative effect at early times,while reaching a certain number, the cumulative effect decay gradually, the displacement and settlement eventually keeps almost constant, plastic deformation is little.Secondly, with the Mohr-Coulomb criteria, a finite element model of plane strain is established using ADINA. Through numerical analysis, the conclusions is as follows: the displacement of concrete panel and settlement of top surface shows similar cumulative characteristics to the model test, which shows attenuation of cumulative effect with the increase of load number, and also the cumulative effect of dynamic load on soil nailing of axial force is not obvious.Thirdly, in order to study response of load characteristics, a series of numerical model with different frequency of load,different stiffness of panels and different dilatants soil angle, are set up. The analysis results is as follows, load frequency has a relatively large impact on the stability of soil nailed structure,the panel displacement shows quasi-linear increase with the loading frequency,the boundary layer thickness,modulus and dilatants angle have little effect on the stability of support structure.Both in model test and numerical analysis, cumulative effect is closely related to mean load magnitude.From above study, some valuable conclusions are drawn, which will be helpful to engineering cases.