Study On Overloaded Railway Subgrade Bed Structure Based On The Strength Of Subgrade Bed Packing

At present,China’s heavy haul railway design specification has not been released officially,At the same time,roadbed design code of ordinary railway train for running large axle design specification is not suitable for the heavy haul trains which axle load is much bigger than before.Therefore,researching on heavy haul railway subgrade bed structure is very important to cater to China railway transportation development and the actual needs,and improve the efficiency of train transport.First,in order to determine the load of heavy haul railway subgrade,by combining the excitation function and the sleeper share ratio method,giving full consideration to the dynamic effect of force of heavy haul railway subgrade bed structure,such as irregularities of train in the running process,and vibration load produced by the local flat scar after the train wheel and rail contact.Secondly,based on the cyclic loading bedding packing long-term cumulative deformation state evolution characteristics,using the method of controlling the strength of roadbed filler to research on subgrade bed structure,and eventually chooses four states of the rapid and stable,long-term and stable,long-term damage,rapid destruction to describe soil subgrade by stress under the cumulative plastic deformation characteristics.At the same time,refers to Datong Qinhuangdao railway subgrade foundation coefficient K30(MPa/m)data analysis and heavy haul railway roadbed dynamic triaxial test data,combined with the requirements of the design code of the heavy haul railway(trial version),calculated the load strength of the railway subgrade filling intensity threshold.And then according to the calculation principle of durability on ballasted railway,determined the heavy haul railway roadbed strength ultimately.Finally,the filler of top layer of subgrade bed is divided into two cases for the graded crushed stone and a filling simulation,then using ANSYS finite element software to establish heavy haul railway roadbed 3D finite element model and analysis structural dynamic forces characteristics.Based on the design principles of subgrade filler strength control,it can not only meet the control requirements of heavy load railway subgrade filling strength,but also save the cost of the project when the bedding surface layer filled macadam,the structure of subgrade bed thickness 2.8m,and when the surface layer of subgrade filled A group filler,the subgrade structure thickness is 2.8m(rich in construction area A filling)or 3.0m(construction area A group fillings scarcity).This paper provides reference for the design and research of the subgrade structure of heavy haul railway.