Research On Key Technology Of Controlling The Top Force Of Large Diameter Long Distance Concrete Pipe Jacking In Loess Area

The rainwater main pipe project of Duling South Road(Yanxiang Road to Weihe Section)in Qujiang New District of Xi'an has the characteristics of large diameter,long distance and high ground drop of rainwater pipe in northwest region,mainly considering the deformation degree of stratum under different jacking forces.Through data investigation,on-site monitoring and numerical simulation,the internal force and deformation of the pipe jacking during the jacking process and the influence range on the soil are carried out,so that the monitoring data,can be better combined with the top force control.The research of the thesis has achieved the following results:(1)Numerical simulation analysis of pipe jacking constructionThe numerical analysis can realistically simulate the whole process of jacking jacking.It is necessary to solve the five key problems of soil and pipe constitutive relations,pipe-soil interface simulation,oncoming resistance simulation,load application method and soil excavation.The numerical simulation top force is selected as 6000kN,OOOkN,8000kN,and the ground settlement values of 0?5m,5?10m,10?15m and 15?20m are excavated under each jacking force respectively,and the simulated settlement value and field monitoring are simulated.The data are compared to study the internal forces and deformation of the pipe jacking during the jacking process and the range of influence on the soil,so that the monitoring data can be better combined for top force control.(2)Research on correcting and twisting method of large diameter long distance pipe jackingDuring the construction process using the pipe jacking method,due to the influence of construction conditions and construction preparation,the jacking force is in a long-term unbalanced state during the jacking process of the pipe fittings,and only instantaneous balance occurs,so the pipe joints are subjected to various external forces and moments.When pushed down,this will cause the joint to advance in a way that deviates from the design route.In order to study the method of correcting and twisting the large-diameter long-distance pipe jacking,starting from the principle of correcting and correcting the twisting,the reason of the twisting of the jacking pipe is analyzed,and the method of basic correcting and twisting is combined with the method of assisting the correcting and twisting.Summarize the empirical methods,apply them in the project itself,and timely adjust the parameters of the top force according to the feedback of monitoring data to prevent and correct the instability of the pipeline.