Applied Research Of Pipe Jacking Technology Under The Conditions Of Special Geology And Environment

Along with the rapid urbanization,the pipe jacking construction technology has been increasingly applied to the urban infrastructure construction,and is currently experiencing an increasing demand in the construction of urban infrastructures such as underground natural gas pipeline,sewage and rainwater pipelines,petroleum,coal gas and electrical pipelines,and cable network.As an underground excavation technology,the pipe jacking construction technology plays a significant role in avoiding many disadvantages in surface construction of buried pipes in cities,reducing the damage to urban roads and the damage to green belts around pipelines,easing the traffic pressure,avoiding the demolition of buildings close to pipeline construction,and lowering the impacts on city appearance and environmental protection.This paper describes the study on pipe jacking construction in a special environment under complex geological conditions,mainly including the following contents:1,Systematically sum up the current situations,means and methods of the study on soil deformation caused by pipe jacking construction,to provide reference for scholars during further in-depth study on the calculation of soil settlement and displacement.2,Introduces the operating principles and characteristics of pipe jacking construction system,and the classification and characteristics of pipe jacking construction projects in detail,particularly the operating principles of slurry balance closed pipe jacking machine and earth pressure balance closed pipe jacking machine.3,Present the calculation methods and empirical formulae of thrust during manual open type pipe jacking construction,slurry type closed pipe jacking construction and earth pressure type closed pipe jacking construction.The ground deformation caused by pipe jacking construction can be calculated mainly through theoretical analysis,finite element method,empirical formula and field measurement.This paper describes the monitoring and calculation of ground deformation caused by the pipe jacking construction of Qinduankou Pump Station and supporting waterlogging drainage works in Wuhan,to improve the prevention and monitoring.Moreover,this paper also describes the monitoring means and methods of existing roads,important facilities and buildings within the range of influence of pipe jacking construction,clearly defines monitoring process,and early warning and alarm standards,and provides timely and reliable monitoring data and information for evaluating the impacts of pipe jacking construction on the surrounding environment,to timely and accurately forecast possible potential safety hazards or accidents,such that related parties have the time to make decisions to avoid major accidents,and can smoothly complete works without any major economic losses.4,Describe the study on equipment and supporting hoisting equipment for the pipe jacking construction of Qinduankou Pump Station and supporting waterlogging drainage works in Wuhan through analysis and study on special construction environment and complex geological conditions,and comparative analysis on the construction durations of relevant projects and the construction quality and equipment of various types under complex geological conditions.Through field test and equipment transformation,the finally selected equipment is reliable,stable and efficient,and can ensure construction quality and meet the requirements of construction duration,thereby improving efficiency,reducing construction cost and avoiding safety risks.5,Simply calculate the jacking force at each pipe jacking section under different geological conditions by means of empirical formulae;provide the control means of jacking speed during pipe jacking construction,and describe the operation of thixotropic slurry system for reducing jacking force and the friction force between arm and soil;introduce the methods,means and steps for correcting deviations occurring in the process of jacking.6,Summarize all information and data obtained through detailed monitoring of important facilities and buildings around pipelines within the range of influence of pipe jacking construction,and then calculate and analyze the application of selected equipment in construction in a special construction environment under complex geological conditions,to ensure successful completion of project construction,control the impacts of ground deformation and settlement on buildings and the construction quality of selected equipment within the standards specified in relevant design specifications,and ensure the equipment selected can fully meet project requirements.