Strain Characteristics of Underground Model Pipe During Incomplete Liquefaction

This paper describes the dynamic behavior of buried pipeline during incomplete liquefaction. Buried pipeline systems have been damaged extensively by soil liquefaction. The procedures of mitigating the damage due to soil liquefaction were recently proposed. The extent that the buried pipe are not damaged should be made clear in advance in case of ground improvement as countermeasures to liquefaction. Therefore it is important to understand the behavior of the buried pipeline during incomplete liquefaction. Experiments were performed employing the pipe whose two ends were free. The pipe was buried in loose, saturated sand stratum. The model sand stratum was vibrated by a transient harmonic wave with a frequency of 5 Hz. The experimental results showed that the dynamic strains took the maximum value as the ratio of excess pore water pressure was between 0.5 and 0.75. This was explained in terms of resonance of the system consisting of the buried pipe and model ground. Furthermore the effects of the buoyancy on the buried pipe and structure during incomplete liquefaction were discussed.