| Trenchless technology used for laying underground pipe line is aimed at laying, repairing and replacing various public installations without digging the ground surface. With fast development of social economic and city construction, the construction and application of various underground projects has increased significantly. Due to the limits and deficiencies of the digging methods, more attention has been paid to the trenchless methods. Compared with digging method, the trenchless technology has advantages of unaffected traffic, undamaged environment, short construction period, low cost, obvious social benefits, and etc. So that it is widely used for laying, replacing and repairing of pipe from under high way, railway, building, river, down area, protective area of historic interest, protective area of crops and vegetation and so on. In the fields of laying pipe line with the trenchless methods, the air pipe rammer, which features simple operation, high precision, fast speed and low cost, is welcome by most of construction units. In the works of laying straight, short distance pipes, the air pipe rammers have good market as the first selected, economic, fast operation technology.Without drag pedestal, the air pipe rammer can push the hollow pipes into the earth by dynamic impact energy. In fact, it is an air impacting tool with low-frequency and high impacting power, which can tamping steel pipes into the earth along the designed trace under the action of the compressed air. In comparison with other trenchless methods, it has many advantages, ie: its matching tools are simple, it is easy in operation, maintenance, shipment and assembly, low in working cost and suitable for various formations. Nowadays it is one of the best method in the field of the trenchless technology used for laying underground pipes.In terms of its advantages, the air pipe rammer is a tool which can not control the direction in the process of laying pipes. Therefore, how to calculate and control its pipe-laying precision and how to prevent the pipe line from out of designed trace are technical key and difficulty for the air pipe rammer in the construction of laying pipes.The intention of this thesis is to work out the precision of air rammer pipe-laying radically. The orientation guide would change the passive direction controlling into active. Ensure the track a level straight line by Real time scouting the track and controlling the direction with the hydraulic pressure system. So we can improve the quality of the construction and increase the distance which the pipe-rammer could pave. The design is to add an orientation guide in front of the pipe, which with four radial pinnas, it can splay towards the anti-direction when the track correction was needed.The orientation guide is a cylinder, the soil cut by the reamer ring could get into the pipe from the orientation guide. There are 4 cabins on the orientation guide, the pinnas could draw back to the cabins and then make the guide a cylinder; there are 2 fluid pressure operated jacks in every cabin, and they can offer the power to splay the pinnas; and there have to be a transmitter in one of the cabins, it can induce the position, azimuth and obliquity the orientation guide being. There are 2 bolts in the front and middle of the pinna to fasten it within the cabin, in order to avoid that the pinnas might be brushed off by the side force while rectifying the direction.Because the tallness in the cabin is little, the fluid pressure operated jacks were designed multi-steps accordingly, 3 steps temporarily, and it could elongate to prop up the pinna.And the signal from the transmitter can be received as other trenchless technology, with a receiver and a remote display. And the navigation system can also analyze and simulate the data received from the transmitter, bring forward the reference directional and obliquitous value for the pinna splaying.In the practice, it often occurs that a single technical method used in some constructions can hardly meet the construction requirements. Specially under the limit conditions of domestic trenchless equipment capacity, the tasks in some constructions could not be completed only by a single technical method, therefore this thesis put forward the design of the active rammer orientation guide, in order to work out the problem of the track excursion for gravity and the complex underground configuration. This design can improve the quality of the construction and increase the distance which the pipe-rammer could pave.With the continuous spread and application of the trenchless technique, the market becomes competitive. Without innovation and development, it is hard to stand in the competitive market. Therefore, it is of very important for this industry to well complete some complex and special projects by means of innovation, applying advanced technique while improving the equipment capacity.Through comprehensive summing-up for the research and practice of the air pipe rammer, the paper is aimed at further developing the pipe-lay technique of air pipe rammer, providing certain theoretical and practical basis and propelling the development of the trenchless underground pipe line technique. |
