Soil Restrains of Oblique Pipelines in Sand

• Main Authors: Chen, Yuh-Jyh, 陳育志
• Other Authors: Hsu, Tung-Wen
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/19936357721464453295

博士 === 國立中興大學 === 土木工程學系 === 90 === This paper presents the soil restraint on the oblique pipelines in sand. A series of experimental tests are conducted in a prefabricated large scale drag box with dimensions 1.83 m  1.83 m  1.22 m. Model pipes 0.61 m long with diameters of 152.4, 228.6, and 304.8 mm are obliquely moved from an axial-longitudinal to lateral-transversal direction in the drag box to study the associated longitudinal and transversal soil restraints of the oblique pipes with various shallow embedded depths. All the test results indicate that for the axial pipes, the longitudinal soil restraint could be estimated as the product of the average of the vertical and horizontal earth pressures at the centerline of the pipe and the tangent value of soil-pipe friction angle. Whereas for the lateral pipes, the transversal soil restraint could be predicted by using the limit equilibrium model with the assumption of either the planar or logarithmic spiral sliding failure surface for the shallow embedded ratio (H/D≦2), however, for the larger embedded ratio (H/D=3) the prediction with logarithmic spiral sliding failure surface method I is more consistent with the experimental results. For the oblique pipes, the longitudinal soil restraint decreases, whereas the transversal soil restraint increases with the oblique angle, respectively. Moreover, the longitudinal and transversal soil restraints of the oblique pipes could geometrically be obtained by multiplying the corresponding cosine and sine values of the oblique angle with the associated longitudinal soil restraint of axial pipe and the transversal soil restraint of lateral pipe, respectively. The findings also indicate that the scale effects are not significant for the size of the pipes tested herein.