offshore pipelines used for oil and gas transportation are often buried to avoid damage from fishing activities and to provide thermal insulation. thermal expansion and contraction of the pipeline during operation can lead to lateral or upheaval buckling. a safe buried pipeline design must take into account a reliable evaluation of soil uplift resistance and pipe embedment depth. while the cost...

For the case of flame thickness being of the order of the pore linear dimension, the flame structure and speed in adiabatic, premixed methane-air combustion in porous media are examined. The local, volume-averaged conservation equations that assume a local thermal equilibrium between the solid and the gas phases (i.e. the single-medium treatment) or allow for a thermal nonequilibrium (i.e. the ...

Offshore pipelines used for oil and gas transportation are often buried to avoid damage from fishing activities and to provide thermal insulation. Thermal expansion and contraction of the pipeline during operation can lead to lateral or upheaval buckling. A safe buried pipeline design must take into account a reliable evaluation of soil uplift resistance and pipe embedment depth. While the cost...

The settlement rate and pore water pressure dissipation are mainly controlled by the permeability of soil. Both laboratory field tests show that is varied during loading consolidation process. It known process accompanied decrease in void ratio which leads to coefficient permeability. importance on time needs be investigated.This paper takes into account change studies its effect characteristic...

Method: In this paper, the shallow formation around the borehole is divided into plastic zone and elastic zone considering it under nonuniform in-situ stress. The collapse pressure formula of shallow formation is derived by taking the shrinkage rate of the borehole as the instability criterion. The fracturing pressure calculation model of shallow sediment under non-uniform in-situ stress is der...

Abstract A high-cycle accumulation (HCA) model predicting the of permanent strain or excess pore water pressure in clay under a large number load cycles is presented. Data from an extensive laboratory testing program on kaolin undrained cyclic loading has been analysed for that purpose. The influence amplitude, void ratio, stress overconsolidation ratio and frequency rates considered constituti...

Pore network models are used to relate fundamental pore structure parameters (pore body and pore throat size distributions) to the distribution of water at the pore level and the decay of proton magnetization under conditions of primary drainage in water-wet rocks. The simulations reveal conditions under which diffusive coupling between pores has a significant effect on the decay spectra and pr...

the main role ofcore in earth dams is to reduce and control the seepage flow through the dam. in order to achieve this purpose, the core material is usually selected from pure or mixed clays.due to very small coefficient of permeability, the clay cores can prevent water leakageeasily. however, pore water pressures developed inside the core during construction, can not be dissipated quickly. as ...