The Research Of Reinforcement Mechanism Of Multi-Layered Geotextile Reinforced Embankment And Load Distribution Coefficient Subjected To Underneath Sinkhole In Karst Terrain

Karst collapse is easy to cause adverse effects on the highway roadbed, It has significant advantages to prevent and treat it with reinforced cushion of multi-layered geogrid reinforced, but at present the design calculation theory is far behind the engineering practice, which greatly hindered its development and application, it is necessary to launch the systemic theory and experiment study on it. Therefore, this paper based on Soil Test, reinforcement pull-out test, and soil reinforcement interface tests, on-the-spot survey various materials' calculation parameters and the constitutive relationship of reinforced soil interface; model test is carried out in the model box which can simulate the collapse condition, deformation and strain in each layer of reinforcement value is measured when collapse occurs, on this basis, analysis of load distribution model and load transfer law of each layer of geogrid; then using three-dimensional numerical calculation software FLAC3 D on test results are validated, and the sensitivity analysis of each influencing factor. Comprehensive analysis and research get the following rules and conclusions, provide the basis for the practical engineering design of geogrid reinforced.(1) Numerical simulation and model test results of the law remained the same, indirectly validated the reliability test data, the simulation ability of the program is strong, it has the certain instructed significance to the design and construction of reinforced geogrid.(2) The numerical simulation under various conditions of each layer of grid distortion rule are same to grid model test, deflection curve close to conform to the parabolic law.(3) under the same conditions, the karst collapse sinkhole width increasing, the greater will be the deflection grille. That is the same of geogrid for karst collapse sinkhole width difference showed different adaptability, specifically to meet the requirements of the maximum deflection grille under the premise, potential karst collapse sinkhole width is smaller, the tensile strength of geogrid is low demand.(4) When reinforced layer reaches a certain value, the experiment of reinforced layer is four, the original grid was little affected by load performance with the increase of reinforced layers, we can look for other changes to improve loading performance of the grid. The numerical simulation also shows that the four layer of geogrid reinforced is the most economic and reasonable.(5) The deflection curve close to conform to the parabolic law subjected to underneath sinkhole in karst terrain, and the deformation decreases from top to bottom, the non-bottom geogrid deformation incomplete and sinkhole scope. In general, compared with single reinforcement, multilayer reinforced cushion can reduce the deformation relatively.(6) The same geogrid specification and geogrid spacing condition in karst collapse sinkhole, the little effect of the width of each layer of geogrid load distribution coefficient.