Analysis The Force Of Glass Fiber Reinforced Plastics Jacking Pipe Joints

Underground water supply and drainage pipe lines are the city's lifeline, but the dense urban buildings, roads and complicated aspect of all other underground pipe lines to the laying of underground water supply and drainage lines will pose enormous difficulties. Pipe jacking, as a non-excavation construction methods, can be more convenient to solve the above problem. The glass fiber reinforced plastics pipe, because of its excellent performance, is to give one of sewer pipe of choice. However, the glass fiber reinforced plastics jacking pipe (GRP jacking pipe) is also very little research, some fundamental questions have not been solved, GRP jacking pipe injury situation often occurs. The key issue of pipe jacking is the strength problem, and the strength problem of GRP jacking pipe can be attributed to joints force, joints force state directly determined its jacking force. Therefore, This article starting from the engineering practice, extract the key issues from engineering, through the GRP jacking pipe joints force analysis to solve the some basic problems of GRP jacking pipe.In this paper, research results and innovations are as follows:1) By introducing the joints open length and deflection angle as the open state of the joints parameters on GRP jacking pipe joints to mechanical analysis, get the joints open length and deflection angle must be meet the relationship when the GRP jacking pipe reach its limit jacking force, and the use of open length or deflection angle to calculate the limits jacking force of the GRP jacking pipe respectively.2) By combination of the key issues in engineering, research and analysis of the maximum allowable deflection angle and the maximum allowed open length, get the allowable jacking force of GRP jacking pipe, the theoretical safety factor to determine,and it should not be less than 3.5; this result applied to the national standards which author involved preparation.3) Through finite element method to study the joints deflection without jacking force, joints deflection under the jacking force, the contact pressure of spigot contact surface, compared with the eccentric force and axis force action, and the effect of rubber ring and wood cushion on the joints, systematic analysis joints force of GRP jacking pipe, to obtain the conclusion of the GRP ring than steel ring has a better ability to withstand deflection, explained of "insert destruction" cause of the accident in pipe jacking project, but also gives a theoretical basis of reasonable choice of rubber rings and wood cushion. The results on the the effect of the pipe joints deflection by FEM and theoretical formula are basically the same.4) On the actual GRP jacking pipe field monitoring to verify the stress on GRP jacking pipe end is uneven because of the joints open or deflection, the same pipe at the same angle into the direction along the axial the stress are not the same, GRP jacking pipe in a more complex stress state, with the theoretical analysis and numerical results are basically the same; the same time, deflection angle tests in the the factory show that:GRP bell ring have enough security and reliability, the test results were compared with the theoretical analysis, good agreement between the two.The one hand, the results of this study contribute to the design and construction of GRP jacking pipe also have important guiding significance, on a certain extent to guarantee the safety and reliability of engineering; the other hand, to correct understanding of the GRP jacking pipe, in order to further promote the application. The part research results has been applied in China national standard "glass fiber reinforced plastics jacking pipe" (GB/T 21492-2008).