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This paper presents the soil friction restraint on the oblique pipelines in loose 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 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 the planar sliding failure surface. For the oblique pipes, the longitudinal soil restraint decreases, whereas the transversal soil restraint increases with the oblique angle, respectively. Besides, both soil restraints increase with the embedded depth. 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.

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Most infrastructures are formed by large amount of parts, like members of truss, decks of bridge, and so on. Relative movement including shearing and extension between members causes load redistribution or even failure. Monitoring the integrity of the structural system can assure its performance and safety. MTDR (Metallic Time Domain Reflectometry) is proposed here to be an intelligent monitoring system using one coaxial cable embedded into members as the sensing and conducting media all the way through the monitored structure. Relative movements between each member at the connecting points are monitored simultaneously by sending a fast rise impulse into the cable. This paper presents laboratory measurements necessary to quantitatively interpret the reflected waveform. The type and magnitude of reflected waveform caused by shearing and extension between members were investigated. The interpretive techniques were defined and verified experimentally. Quantification between reflected waveform change and amount of relative movements are achieved and provided.