Abstract
The present design criteria for irrigation pressure pipelines prescribes that the thrust force acting on the bend section of the pipe is supported by the passive earth pressure. However, a decrease of the resistance force due to liquefaction has not been considered for the design, and rational aseismic design method has not been developed. In the present study, we conduct lateral loading tests for the buried pipe model under different hydraulic gradient, and try to verify the mechanical characteristics of several countermeasures which use gravel and geogrid. From the experimental results, we clarify that the shear resistance of the gravel bed decreases due to liquefaction of the sand bed surrounding the gravel zone. On the other hand, when the geogrid is combined with the gravel, the tensile force of the geogrid is given to the lateral resistance force, and sufficient strength is obtained.
