Page 169 - Trenchless Technology Piping Installation and Inspection
P. 169

Pipe and Pipe Installation Considerations     135









                                       Region of wall thinning due to corrosion

          Longitudinal crack











          FIGURE 4.11  Longitudinal splitting of rigid cast-iron pipe. (Makar, 2000.)



                      Missing pipe section
















                                               Spiral crack

          FIGURE 4.12  Spiral crack in rigid cast-iron pipe. (Makar, 2001.)

              Frost load     Circular or circumferential break

                                                       Poor compaction




                             Poor bedding     Swelling clays
                  “Sagging”                   “Hogging”
     FIGURE 4.13  Bending or fl exural failure in pipelines. (Rajani et al., 1995.)
   164   165   166   167   168   169   170   171   172   173   174