Research On The Key Technology Of Bump At Bridge-head Of The Expressway

The highway construction in China has been developed at high speed in recent years,with a rapid increase in highway mileage.However,the blind pursuit of the number and short construction period result in many problems,and bridgehead jump is one of the most prominent problems.The so-called bridgehead jump refers to the occurrence of the faulting of slab ends or longitudinal slope changes due to a differential settlement between structures such as the bridge culvert passage way and its embankment at the abutment back,resulting in jump phenomenon occurring when vehicles pass through a bridge junction at high speed.In today's highway construction,the bridgehead jump problem has become a problem to be urgently solved.In this paper,the causes of vehicle jumping at the bridgehead and its hazards are discussed,the jumping mechanism of bridgehead jump is researched deeply,and the vertical curvature radius and ratio of altering gradient of longitudinal slope for the critical vehicle bump are obtained.In this paper,the differential settlement manifestation form and the differential settlement control theory are analyzed and discussed,and the standard of differential settlement control is put forward by considering factors such as safety and comfort.Aiming at the different structural layers of highway,the paper puts forward the prevention and control of highway bridgehead from three aspects of foundation prevention,control of embankment at abutment back,and transitional road surface control.There are series of control measures such as replacement method,CFG pile method,technology of high-speed hydraulic compactor,fly ash,bridging slab method and default reverse longitudinal slope method,and their key technologies are analyzed and studied.Software has been used to simulate the settlement law of the backfill of abutment back,which will lay a theoretical foundation for the prevention and control of bridgehead jump with reasonable control technologies.Combined with the engineering practice,the application of Rapid Hydraulic Impact Compactor in the backfill of abutment back is studied,and the compaction effect of the high-speed hydraulic compactor is comprehensively analyzed through software simulation and field test.Through the comparison and analysis,advantages of the high-speed hydraulic compactor technology in the application of the prevention and control of the bridgehead jump is highlighted,with a high value of the promotion,which provides a valuable reference for the further study of prevention and control of the highway bridgehead jump in the future.