Characteristics of Uplifting Velocity of a Buried Pipe in Liquefied Ground

Uplift behavior of a buried pipe is a typical damage to structures in liquefied ground. Since uplift of pipes could causes the functional loss of emergency supply of fire extinguish water, and the ground surface deformation due to these uplift of pipe could be a barrier for rescue transportation, an evaluation scheme of uplift deformation level in various ground conditions should be proposed. A series of shaking table tests was conducted to investigate the uplifting velocity of a pipe during shaking. Test results revealed the uplift velocities in various soils were dependent on the soil characteristics; especially the effect of fines contents. In comparison with the case with viscous waters, these effects might be not based on the effect of permeability. However, hollow-cylindrical cyclic shear tests indicated that the difference should be based on the difference of stress-strain relationships. Thus, the importance of laboratory test to evaluate the behavior of soil during liquefaction is clarified.