On-site Investigation And Disturbance Control Of Rectangular Box Culvert Underpassing Highway Subgrade

With the increasing expansion of the national transportation network,the spatial contradiction between the newly planned road and the existing highway has increased dramatically.In order to cross the normal operation of the highway and reduce the interruption of existing lines,the use of box culvert thrust under construction has the advantage of "low disturbance,high utilization rate".At home and abroad,shallow overburden,large cross-section,long distance box culvert jacking projects are common,control conditions and construction needs are increasingly demanding.There are still many problems in the project need to be solved.This master’s thesis will be based on the reconstruction project of S439 provincial road and the example of Jing-men east extension section of Xing-hua 3rd road under-passing the G55 highway in Hubei Province.The research is carried out by means of on-site investigation,numerical calculation and theoretical analysis.The main research contents are:(1)Combined with the project characteristics,high frequency field monitoring was conducted on the deformation of the existing line pavement,box culvert attitude and roadbed reinforcement system during the jacking construction.Based on the actual measurement data,the disturbance law of box culvert jacking construction is summarized and analyzed,and the construction evaluation is carried out for the engineering example.(2)Based on the actual projects,the numerical analysis model established to explore the influence of different geological conditions,thickness of overburden on box culvert and other factors on the deformation of existing line,stability of roadbed,internal force of box culvert and support structure,friction characteristics of box-soil interface.(3)Considering the geological conditions,box culvert section size and other factors,the applicability of Peck’s formula is analyzed in depth.With the help of elastic mechanics theory,the soil displacement calculation method applicable to the box culvert underpass construction is derived.The measured data are included in the comparison together with the calculation results of stochastic medium method to analyze the influence law of calculation parameters.(4)Summarize the deformation law of the existing pavement caused by the underpass projects and design a standard calculation method for pavement settlement control.According to the results of 32 groups of mixed horizontal orthogonal tests,the pavement deformation control benchmark in the construction of rectangular box culvert underpassing highway is constructed and verified by examples.Figure 117,Table 22,Reference 106...