Studying the load of the working equipment of the knife pipe deepener for trenchless laying of engineering communications by the pulling method

Abstract

Problem. This article is devoted to the study of the load of the working equipment of the knife pipe boring machine for trenchless laying of linear underground engineering communications by pulling them through the soil. The implementation of this method requires significant traction efforts, which causes big stress in its working equipment. Understanding their meaning is important when designing these machines. Goal. The purpose of the research is to create calculation schemes and mathematical models that will allow you to get an idea of the load on the work equipment and provide it with a qualitative assessment of its stress state. Methodology. In order to achieve the set goal, an idea of the dynamics of work processes of earthmoving and transport machines was put forward. Results. The obtained results made it possible to carry out an analysis of the loads on the working equipment of the pipe dredger, taking into account the processes that occur during the meeting of the knife working body with an obstacle in the process of movement. Namely, it was established that when the back knife of the working equipment meets with obstacles, the stiffness of which increases, from 10.000 to 20,000kN/m, it does not lead to a significant increase in the operating loads, which can be explained by a significant difference in the stiffness of the obstacle and the working equipment. It is possible to reduce the maximum operating loads from 270 to 210kN, or by 27% by reducing the stiffness of the working equipment from 2000 to 500kN/m due to the use of additional elastic nodes or elements that absorb dynamic loads in the metal structure of the knife equipment of the machine. The most significant reduction in operating forces can be achieved by reducing the speed of movement in areas where obstacles are likely to be encountered. The conducted studies showed that changing the movement speed from 1.5 to 0.5 m/s allows to reduce the resulting forces from 330 to 190 kN, or by 43%. Scientific novelty. For the first time, calculation models were obtained for determining the dynamic load of the working equipment of knife pipe boring machines during its collision with obstacles.. Practical value. The results of the research can be recommended for practical use in the design of knife-type pipe deepeners, which are intended for trenchless laying of underground communications.