Abstract
Evaluation of seismic performance on buried pipeline changes whether the pipe slips against the surrounding soil or not. When slippage takes place, stress and strain concentrate to junctions and bends. Important factors of slip or not-slip are critical shear stress of soil (τcr) and elasticity of pipe materials. As there were few reports of experiments about polyethylene pipe(HPPE), we conducted the experiments to investigate the performance of HPPE. Our results obtained are : (1) τcr of HPPE with EF coupler is around 11.7kN/m2 under the 60cm of backfilling soil. Therefore we adopted τcr of 10kN/m2 which comes from the experiments of steel pipe, although a large difference of elasticity between HPPE and steel pipe. This means the existing seismic design method of buried pipeline can be applies to HPPE. (2) we found, however, that even HPPE can slip a little in solid ground because of the short wavelength. Then we have to estimate the influence of slippage against junctions and bends to confirm the seismic design method of HPPE.
