| Normally,engineering construction should avoid fault zone as far as possible,and relevant engineering regulation has ruled how should projects avoid it.But when roadbed projects have its specific characteristics that crossing the fault zone can’t be avoided,it is a thing that frequently happened that it intersect or parallel with the strike-slip fracture zone,like Sichuan Tibet Railway,Qinghai-Tibet Highway and Qinghai-Tibet Railway,etc.After earthquakes happened,ordinary projects can hardly resist the fierce deformation of the surface,railroads and highways are the lifeline project of the emergency rescue,the results are unimaginable if it was damaged and made the traffic jam.That made the comprehensive requirements of its safety and anti-break performance apart from the free passage of linear engineering like railroads,highways and tunnels.This passage take one high embankment of Yunnan-Guizhou Railway which crosses the active strike-slip fracture zone as a model,using ABAQUS finite element software to numerical analyze factors like the roadbed-fault different intersection angles,fault dislocation momentum and using geogrid under the base of roadbed,and complete the analyze of roadbed’s damage model and mechanism as well as the research on the measures of anti-seismic and shock absorption under the influence of strike-slip fracture layer’s movements.(1)Using numerical simulation to numerical analyze different roadbed-fault intersection angles and fault movement figures,it is find that the fault intersection angle has important influence on the horizontal displacement of roadbed and stress of front and rear side lopes,as well as the strain change.With the reduction of fault intersection angle,the relative displacement of roadbed reduce;peak of the compressive stress increase and transfer from the fault line to the fixed plate.Take the fault line as the boundary,vertical strain’s distribution characteristics of roadbed present antisymmetric distribution as the upper and lower wall,but the peak figure of stretching strain is greater than the compression strain.As the tensile capacity of roadbed is under the capacity of compression,the damage of tensile failure caused by fault movement could be more serious.(2)It can be seen from the cloud chart of roadbed’s horizontal displacement that the strike-slip fault movement isn’t just impact the roadbed,the soil body around the roadbed will produce plastic deformation with the whole movement of roadbed,forming a range of influence,which the centre of a circle is the fault-roadbed’s intersection,the two sides are semicircle,and the range which is affected of the soil mass of staggered plate is wider than the fixed plate.(3)Develop the new model box for strike-slip faults and introduce the indoor large-scale physical model experiment’s design,actualize and important experiment equipment detailedly to offer technical support for the experiment’s carry out.Also,making soil example according to the model test of the roadbed prototype and major figures’ similarity ratio,getting the major parameters of making model soil samples through indoor compaction test,dir4 ect shear test and unconfined compression test.(4)By imposing geogrid resistance measures’ analog result and validate its test results.Acquiring the roadbed’s horizontal displacement curve,stress of front and rear side lopes and the distribution of vertical strain’s curve and presenting the result of numerical analyzing results of comparing with the prototype roadbed.(5)Through numerical simulation and model test,the passage discussed the resistance measures’ mechanism of using geogrid on roadbed to absorb shock from the change regulation of multiple angles including horizontal displacement,variation of stresses,vertical strain distribution regulation and the roadbed damage conditions,in order to provide scientific evidence for established roadbed and roadbed projects’ anti-seismic and strengthen that will be established afterwards. |
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