טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentTokarev Dmitry
SubjectAnalysis of Durability of the Rigid Force Mains
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Hillel Rubin
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

This research concerns the durability of rigid pipes (which are made of concrete, asbestos-cement, etc.). Accumulated field experience shows the presence of solid particles in the flowing water may lead to significant pipe wall abrasion. The pipe wall abrasion occurs in sanitary and drainage sewers because the water flowing in such pipes always conveys some quantities of solid particles.

Parts of the research work focuses on the hydraulic aspects of the pipe wall abrasion by carrying out a relevant laboratory study. The work also incorporates a quantitative analysis and calculations of the rigid pipe durability under different conditions of field service. The major objectives of this study are:

·        To identify basic properties of the solid particles determining the geometry of the groove that develops at the rigid pipe invert.

·        To provide proper means for the evaluation and calculation of the effect of the groove on the pipe durability.

The experimental part of the study was carried out in the Hydraulic Laboratory of Technion, where an experimental set-up of Darmshtadt abrasion testing method has been constructed. The experimental results yielded the relationship between the groove geometry and its rate of formation and the characteristics of the solid particles. We have used the dimensional analysis and friction force calculations to characterize the pipe wall abrasion in the real world of the pipe service.

Our numerical modeling, simulations and analysis were carried out by applying the numerical code ANSYS. The simulations included reference to the entire region of rigid pipe loading, starting form external load alone passing the combination of the external load with the internal pressure and ending with the internal pressure. We applied our simulations to get the failure curves of Schlick for the simulated pipe loading. We applied the numerical results to get graphical presentations of Schlick's failure curves. For grooves of different geometry we defined and identified lines of failure stresses by applying the basic equation of Shlick and extending it to pipes with grooves at their bottom. The method was applied to grooves of different geometries.