Soil–structure interaction for deeply buried corrugated steel pipes Part II: Imperfect trench installation

The potential benefits of the imperfect trench installation method were studied for corrugated steel pipes. The imperfect trench installation method has mostly been used to reduce earth pressure on buried rigid pipes by inducing reverse soil arching over the pipe. Because corrugated steel pipes are relatively flexible, they induce a small amount of reverse soil arching. Therefore, there has been limited research regarding the effects of imperfect trench installation on flexible pipes such as those fabricated with corrugated steel. The objective of this study was to demonstrate the efficiency of the imperfect trench method for buried corrugated steel pipes. An optimum soft zone geometry for imperfect trench installation is proposed to maximize the reduction of the earth pressure on buried corrugated steel pipes. Predictor equations for arching factors, maximum stresses, and deflections of corrugated steel pipes were formulated that incorporate the proposed optimum soft material zone geometry. Parametric studies revealed that the proposed imperfect trench installation can reduce the maximum wall stress by as much as 69%.