Study On Design And Planning Of Bridge Foundation Under Karst Geological Conditions

China is one of the countries with the most extensive karst geological distribution in the world.With the rapid development of highway bridge construction,it is inevitable to encounter poor karst geological conditions.When building bridges in karst areas,karst geological conditions have a great impact on the engineering cost and safe use of bridge infrastructure.On the premise of meeting the construction and use safety,a reasonable bridge foundation form will greatly reduce the construction difficulty of the bridge,save the cost and improve the comprehensive benefit of the whole bridge project.Therefore,in this paper,based on the project of oil pipeline bridge on Forest Avenue in Wuhan,the method of foundation bearing capacity test,numerical analysis and theoretical calculation is used to carry out the scheme design and comparison of bridge foundation under karst geological conditions.(1)Analyze the engineering geological conditions of the bridge site of the oil pipeline protection bridge in Forest Avenue of Wuhan,investigate and study the regional geological conditions,hydrological environment conditions,geological structure and other conditions of the bridge site,and analyze the form and development characteristics of the karst in the site.On the basis of the above,the field load test of karst geology is carried out,and the data analysis is carried out to determine the characteristic value of foundation bearing capacity.(2)Study the theoretical knowledge of bridge foundation in karst area at home and abroad,analyze its applicability and scope of application.According to the karst geological conditions of the bridge site,the existing theoretical basis and engineering examples are used for reference.The foundation type to be adopted is pile foundation or enlarged foundation to solve the problem of local distribution of karst at the bottom of the bridge.(3)Karst caves are often encountered in karst developed areas.Through the finite element analysis software MADIS / GTS,the influence of karst caves on bridge pile foundation and foundation expansion is studied and analyzed from two aspects.These two aspects include the influence of different size and distance from the bottom of the foundation to the foundation,which provides a good reference value for engineering design and construction.(4)Under the karst geological conditions,carry out the bridge foundation scheme design and comparison.Aiming at the construction difficulty,project cost,the influence of karst cave and bearing capacity,the reasonable bridge foundation scheme is selected through comparative analysis.(5)According to the selected foundation type,the treatment measures for the karst caves in the bridge site area are proposed,and grouting or replacement are adopted.In the process of bridge foundation construction under karst geological conditions,the construction management should be strengthened,including quality management,safety management and technical management,so as to further improve the comprehensive benefits of the project.