Study On Treatment Measures For Railway Subgrade With Cross-Tectonic Ground Fissure

With the rapid development of China’s railway construction,the common linear geological disaster of ground fissures has become an important factor restricting its construction and operation.Ground fissures not only threaten the safety of urban buildings,but also have great impact on railway systems across provinces and cities Big impact.The research results of the past railway engineering crossing ground fissures show that the railway crossing ground fissures are basically bridged.When the engineering area is not suitable for building bridges or the cost of building bridges is large,the soil materials in the ground fissure area can be replaced to improve and Strengthen the nature of the soil in order to meet the requirements of railway engineering construction,that is,use the roadbed to cross the ground fissure zone.Through field investigation and data analysis,the development characteristics,profile structure,active age,dislocation amount,influence range and engineering properties of ground fissures are summarized;large-scale physical simulation experiments of ground fissure activities are carried out to describe the generation,development and Through the phenomenon,summarized the law of ground fissure movement;and using PFC5.0 software for numerical analysis to simulate ground fissure movement,analysis of typical ground fissure movement characteristics.The specific geological problems in the ground fissure area are divided,the disaster characteristics and different manifestations of the ground fissure area are elaborated in detail,the application scope,advantages and disadvantages of different railway subgrade forms are explained,and the roadbeds for the construction of railway projects in different ground fissure areas Classification.The Flac software was used to numerically simulate the four different working conditions of the foundation,including fine-grained soil,loess,modified soil,and crushed stone,and the thickness of the overlying soil layer was 2m,3m,and 4m.The simulation results of different working conditions were analyzed and compared,and under the conditionsof the same settlement range,when the ground fissure dislocation amount did not exceed50 cm,the foundation was treated with gravel material and the thickness of the overlying soil layer was appropriately thickened.Can meet the requirements of railway operation.Combined with related projects,it is finally concluded that under the condition of gravel material foundation,at the same time,an appropriate thickened ground crack overlying soil layer is selected,and the safety of the railway operation can be further improved by using reinforced soil,geogrid and other methods to strengthen the foundation soil sex and stability.