Mechanics And Failure Characteristics Of Geocell And Retaining Wall Block Under Dynamic And Static Load

Geocell has excellent three-dimensional reinforced effect,so that in a variety of support and reinforcement works has been widely used.Due to the complexity of the effect of the soil and the influence of many other factors,the bearing mechanism of the reinforced structure under the dynamic load is still lack of sufficient understanding.In this paper,taking " the mechanism of the geocell and the block and the destruction of the characteristics " as the core research content,carrying out the work of the information research related with the project,implementing the large proportion indoor model test of the geocell reinforced soil retaining wall under the action of static and dynamic load,and taking the indoor test as the prototype,carrying out the numerical simulation study with the use of finite difference method software FLAC3D5.0.The main research contents and achievements are as follows:In order to optimize the test method of single variable control,the geostatic chamber was designed by using the self-designed 300 cm × 160 cm × 200cm(length × width ×height)retaining wall model test device,applying the static and dynamic load by MTS electrohydraulic servo loading system.Conducting the reinforced retaining wall large model test(geocell height H = 5cm and 10 cm,3 layers and 6 layers of reinforced layers,the application of static and dynamic load of 5 kinds of test conditions),analyzing the variety of the physical and mechanical parameters as the ultimate bearing capacity,the acceleration response,the earth pressure and the horizontal displacement of the retaining wall under static and dynamic load,studying the fracture of the reinforced retaining wall and the failure law of geocell,revealing the mechanism of force and failure characteristics of geocell and retaining wall block.The experimental results show that the main force points of the geocell are concentrated at the riveting point of the geocell under the action of static and dynamic load,and the ultimate strength of the geocell is determined by the tensile strength of the riveting point.The fracture surface of the top and the side of the model is much smaller under more layers and higher of the geocell,and the fracture position of the geocell mostly concentrates on the position and the development trend of the fracture surface measured from the model.The positive and negative symmetrical distributions of the dynamic acceleration peaks and valleys coincide with the applied cosine dynamic carrier waveforms.The acceleration in the vertical direction is significantly larger than that in the horizontal direction,and the acceleration in height below the loading plate is significantly larger than the acceleration which is close to the acceleration of the inside of the block panel,and the contribution of the moving frequency to the acceleration is very obvious.The maximum acceleration value at 8Hz is 20 times that of 2Hz;the internal acceleration of the retaining wall decreases gradually with the load growth,and staying at lower values finally.Under the additional load,geocell as reinforcement,connecting the filler soil with the wall,improving the integrity of the retaining wall model.Additional load acting on the top of the wall model soil,due to stress deformation and other effects,the occurrence of mutual friction between soil and reinforcement.While its lateral deformation to promote the wall outward movement,the wall are bound by the geocells.Before the destruction of the load,greatly reducing the deformation of the wall,which obviously embodies and exerts the flexible mechanism of reinforced earth retaining wall.Based on the laboratory model of geocell reinforced soil retaining wall,building the finite element model of FLAC3 D geocell reinforced soil retaining wall and compared with the indoor test.The simulation results show that the vertical force of the geocell is mainly concentrated in the connection point of the geocell,which is consistent with the the indoor test in stress.Both laboratory tests and numerical simulations show that maintaining the number of reinforced layers unchanged,changing the height of the geocell,can significantly constrain the horizontal displacement of the retaining wall block,but not significantly reduce the settlement of the top of the retaining wall,geocell plays a important role in effectively restraining lateral displacement and enhancing soil bearing capacity.