ABSTRACT
Sinkhole formation due to internal erosion around defective sewer pipes is identified as a serious problem. One of the effective methods of minimising this type of sinkhole formation is by enhancing the performance of pipe embedment materials against erosion. In this paper, the influence of the crack width with respect to the maximum particle size of the pipe embedment material was examined for a widely used pipe bedding material using a laboratory scale physical model apparatus. The erosion due to pipe defect was evaluated by means of eroded soil mass, ground deformation, scale of the cavity size and damage induced for three different crack widths. Results for maximum particle size of 4.75 mm indicates that once the crack width exceeds the maximum particle size of the bedding material, cavity progression and soil erosion rate accelerated rapidly. Furthermore, it was identified that particles less than 0.3 mm were highly susceptible to erosion.
