Research On Bearing Characteristics Of Temporary Anchorage Group Pile Foundation

The anchorage is a key component of the suspension bridge.It carries most of the weight of the suspension bridge and also carries the huge load from the cable.The foundation soil receives the load from the upper part through it.The anchorage structure contributes greatly to the safety and stability of the suspension bridge system.As an emerging technology,temporary anchorage is currently less applied in China.Only the Suzhou Zhuyuan Bridge and the newly-built Nanguang Railway Bridge have applied this technology.However,the use of group pile foundations in the suspension bridge structure is also very important.rare.In view of the obvious lack of research on temporary anchoring technology,it cannot meet the needs of a large number of applications in actual projects in the future.The construction of the Dongjiang South Tributary Harbor Bridge in Dongguan City,Guangdong Province,which I participated in,applied this technology.Therefore,this paper has carried out theoretical,numerical simulation and field experimental research on the bearing characteristics of the temporary anchor pile group foundation.The work content is as follows:Enter the Dongjiang South Tributary Harbor Bridge project in Dongguan City,Guangdong Province,always grasp the construction nodes,connect relevant equipment in series at the key nodes of the construction,and install the inclinometer,fiber grating sensor,fiber grating earth pressure box required for on-site monitoring in time,Fiber Bragg grating anchor cable dynamometer,etc.After the installation is completed,the equipment will be debugged on site and the survival rate will be tested.After the temporary anchorage cable was successfully erected,that is,the load application is completed,on-site monitoring of the temporary anchorage pile group foundation of the Dongjiangnan Tributary Gangwan Bridge is carried out.Through the inclinometer tube,fiber grating sensor,fiber grating soil pressure box,cable tension meter and other equipment,the displacement,bending moment,soil pressure on the front side of the platform and cable tension of the temporary anchor foundation under the action of the cable tension are lengthened.Up to three months of monitoring activities.At the same time,follow-up processing of the measured data is carried out to study the bearing performance of the group pile foundation.The finite element software ABAQUS is used to conduct multi-factor analysis of the temporary anchorage structure,in order to obtain the change of the bearing characteristics under the change of the pile length,pile diameter and other factors,and then change the load analysis of the change of the load sharing ratio of the pile cap and the pile group foundation.At the same time,the effective reinforcement range of the soil is studied,and suggestions are made for the foundation reinforcement of the construction site.Finally,the theoretical calculation method of the pile group foundation is studied.First,the m method is used to calculate the overall force model of the pile cap and the pile group according to the p-y curve formula of the cap and the existing p-y curve formula in the clay and sand.The monitoring results are compared and the advantages and disadvantages of each method are analyzed.After on-site monitoring,finite element and theoretical calculations,the working conditions are obtained through cable tension monitoring,and the data is processed to obtain key factors such as the earth pressure of the pile cap,the bending moment of the pile,the shear force,the earth pressure of the pile,and the displacement of the pile.According to the finite element analysis,it is concluded that the pile diameter is a factor that has a greater impact on the bearing performance of the temporary anchorage than the length of the pile.The load sharing situation of the cap and pile group foundation under the load change is obtained,and it is proved that The effectiveness of the foundation reinforcement program.After theoretical calculations,it is concluded that the p-y curve method is more accurate and closer to the actual engineering method.This paper is dedicated to exploring the performance characteristics of temporary anchorage pile group foundations in actual engineering,and studying the changes in bearing performance under different sizes and loads,and comparing the theoretical calculation results,hoping to provide a reference for the application of this technology in the future.