Research On The Causes Of Cracks In High Piled Wharf In Doumen Port Of Zhuhai And The Reinforcement Measures

With the substantial increase in the throughput of coastal ports,the construction of port projects began to develop in the deep water.Due to the good adaptability of the high piled wharf to the deep water port,the high piled wharf has been widely used in our country in recent years.However,the durability of the high piled wharf is poor,and the section of the pile is vulnerable.The corrosion of steel bar caused by structural cracking is the most important and the most dangerous cause of the damage of reinforced concrete structure in high piled wharf.Therefore,it is very important to study the causes and treatment of wharf pile foundation.In this paper,the security problems of cracks in the Zhuhai Doumen port wharf are studied and the reinforcement scheme is designed,the specific work includes field investigation,geological survey,model experiment,finite element analysis,reinforcement design,monitoring scheme design,etc..(1)Supplementary survey and test: through field investigation and collection of wharf construction materials,achieved a comprehensive understanding of the wharf structure and the actual use.In order to determine the current state of the soil on the shore slope,a geological survey and geotechnical test were carried out,the basic physical properties and mechanical properties of the samples taken from the borehole were tested,provides a more accurate soil material parameters for finite element analysis(2)model test: at the top of the pier and the concrete roof of the platform,there is a single tensile crack in the direction of outward(sea).Through the single pile model test,it is recognized that the cracks on the sea side of the pile foundation are caused by the force exerted by the displacement of the platform.(3)Calculation analysis:Finite element analysis and calculation using the international general finite element software ABAQUS.Three dimensional finite element model is established according to the actual working conditions of the wharf,and the fine analysis of various conditions is carried out by taking into account the load of the bank slope,the dredging of the harbour basin,the mooring force of the ship and the load of the wharf.According to the analysis results,under the action of the bank slope,the soil has some consolidation deformation and outward displacement,which is the trend of the overall displacement of the bank slope,but this is not the cause of the cracks.The combined effect of the dredging of the basin,the pulling force of the ship and the vertical stacking of the wharf deck are the causes of the cracking of the pile foundation.The calculated results of finite element are consistent with the fracture morphology.(4)Reinforcement scheme and monitoring scheme design: The tie bar is arranged between the wharf and the embankment,which provides the wharf with horizontal pulling force in the direction of the bank,and limits the horizontal displacement of the wharf platform,so as to achieve the purpose of controlling the further expansion of the pile foundation crack.In order to monitor the safety of the operation of the terminal,it is recommended to install steel bar in the welded joints,monitoring the reinforcement may withstand the pull from the platform.At the same time,it is necessary to arrange the appropriate displacement measuring points,and the total station is used to monitor the displacement of the wharf platform and the yard.(5)Research on calculation method of concentrated force distribution coefficient on the level of high pile wharf,by considering the influence of pile and soil stiffness and pile depth,a calculation method is put forward on the inclined slope of high pile wharf horizontal force distribution coefficient.