Research On Rectangular Tunneling Machine Used For Utility Tunnel Excavation

The rectangular tunneling machine is a kind of equipment which can realize tunneling construction of common trench with rectangular cross section in the area where it is difficult to carry out the open excavation construction such as city center and protection area of ancient buildings.With the increasing demand for common trench in major cities,the research on this kind of equipment is very urgent and has a bright future.In this paper,the overall structure,the construction technology,the cutter head and other key components of the device are studied.the specific contents are as follows:By comparing and analyzing a variety of soil pressure analysis theories,the more rational Terzaghi theory is selected to analyze the earth pressure of the excavation formation.According to the principle of earth pressure balance,the relevant parameters of the spiral soil equipment are analyzed and calculated.The vertical and lateral earth pressure of the formation,the thrust required by the cutter head and the whole machine in the construction process,the main structural dimensions and performance parameters of the spiral soil equipment are calculated,which provides a theoretical basis for the overall structure of the device and the design and selection of the main components.A spoke-type double cutter heads with retractable handle is innovatively designed.The cutter head structure,the tool selection layout and the cutter head drive mode are designed.The innovative application of the crawler chassis enables the separation of the cutter head propulsion and device propulsion.The sliding propulsion at the bottom of the traditional shield shell is changed into rolling form,which effectively reduces the propulsion resistance and the installed power of the device.The synchronous construction method of tunneling and cast-in-place lining is introduced,and the rectangular shield shell,locking mechanism and propulsion mechanism of the cutter head are designed according to the technical requirements.Finally,the 3D model of the tunneling device’s whole device is established,and the main technical parameters of the device are determined.The cutting path chart of each tool and the cutting speed curve of each cutter and five pyramid cutter are obtained by kinematic simulation analysis,which provides the theoretical basis for the selection and replacement of the tool in actual construction.By analyzing the cutting mechanism of cutter and retractable handle and combing fact,the cutting torque required for cutter work is calculated and the finite element analysis is carried out on the cutting force of cutter head under different cutting depth.The results show that the change of cutting depth has little influence on the strength and stiffness of the cutter head,and the strength and stiffness of the cutter head meet the requirements.The reliability analysis and evaluation of the key stress components on the device are carried out by using SolidWorks Simulation,including the static stress intensity analysis and the finite element fatigue analysis.The results show that the strength,stiffness and fatigue life of the key components such as the propulsion mechanism of cutter head,the drive shaft of cutter head,the locking screw shaft and the connection block of shield shell are all meet the construction requirements,and the structure design is reasonable.