Cracking in polymer concrete pipes-comparison of exact events in a pipe jacking project and numerical 3D modeling analyses

摘要

In this paper, the performance of a slurry micro-tunneling machine used for the Tehran Sewage network plan which is under construction, is presented. The total project route is 3855 meters. Total numbers of manholes are 30 which are constructed after which the pipe jacking is completed. Polymer concrete pipes with 1400 mm, 1600 mm and 1800 mm diameters are used at this project which 56% completed until the paper is being prepared. A Brief description of the project including the Herrenknecht micro-tunneling machine and shaft and pipes are presented. Geology condition and water table are briefly described. In addition, some obstacles encountered during execution of the Tehran pipe jacking project are described. One of the biggest obstacles was the location of the site (at the center of capital) that put this project in the category of urban projects. The second obstacle consisted of the pipe jacking operation through an unstable river bed and loose soil and some other problems with the special geology of the site. Three operation methods during project were considered: 1. Using FRP 2. Using bolts around the crack 3. Using one designed structure to connect to pipes in rear and front of cracked pipe known as the Steel Jacket method For each method an exact model in ANSYS software was built and analyzed to compare and choose the best way for controlling the cracking. We used exact jacking forces during performance of the pipe line and put these forces into each model to study variations of crack during pipe jacking. This paper includes useful information about cracking in concrete polymer pipes and comparison of exact result with numerical 3D modeling is included.