Impedance of Inner Saturated Soil to Horizontally Vibrating Large-Diameter Pipe Piles

An analytical solution for the inner soil impedance of saturated soil to a horizontally vibrating large-radius pipe pile was presented. Based on the porous media theory and the assumption that the vertical normal stress is zero, the closed solution of the inner soil impedance of the saturated soil to the movement of the large-diameter pipe pile is obtained. This analytical solution considers the influence of saturated soil parameters on the impedance of the core soil of large-diameter pipe piles. Through numerical examples, the variation law of the inner soil impedance with pile radius, pile length, dimensionless frequency, compression coefficient, effective permeability coefficient, and porosity was analyzed and the pile radius corresponding to effective inner soil impedance is determined.

Field measurement of contact forces on rollers for a large diameter pipe conveyor

An intensive field measurement was carried out to assess the force acting on the rollers for a large diameter pipe conveyor. A special idler enclosing two dynamometers was designed and installed in the various roller positions. The forces on the rollers were metered while the conveyor was running with and without conveying material. The position of the two dynamometers was such allowing to derive the theoretical contact point of the belt onto the roller. The measurements were carried out in a straight section of the pipe conveyor and in the centre part of a horizontal curve. Obtained data are presented, analysed, and compared with the values from a six-point stiffness testing device. Further, the participation factor of the material load on the roller forces for a single roller is derived. The study concludes with a critical review of the findings comparing them with results presented in the literature.

An Analytical Method for the Longitudinal Vibration of a Large-Diameter Pipe Pile in Radially Heterogeneous Soil Based on Rayleigh–Love Rod Model

Based on the Rayleigh–Love rod model and Novak’s plane-strain theory, an analytical method for the longitudinal vibration of a large-diameter pipe pile in radially heterogeneous soil is proposed. Firstly, the governing equations of the pile-soil system are established by taking both the construction disturbance effect and transverse inertia effect into account. Secondly, the analytical solution of longitudinal dynamic impedance at the pile top can be achieved by using Laplace transform and complex stiffness transfer techniques. Thirdly, the present analytical solution for dynamic impedance can also be performed in contrast with the existing solution to examine the correctness of the analytical method in this work. Further, the effect of pile Poisson’s ratio, pile diameter ratio as well as soil disturbed degree on the dynamic impedance are investigated. The results demonstrate that the Rayleigh–Love rod is appropriate for simulating the vibration of a large-diameter pipe pile in heterogeneous soils.

CFD Analysis of S-Gamma Model Coupled With Two-Group Interfacial Area Transport Equations and AMUSIG Model for a Large Diameter Pipe

This paper describes the modeling of flow regimes beyond bubbly flows in a large diameter channel considering polydispersity and bubble induced turbulence using the Eulerian two-fluid approach. A two-bubble-group approach with two-group interfacial area transport equations (IATEs) is used to demonstrate flow phenomena in a large diameter pipe. Source and sink terms for mass and momentum exchanges between the two groups of bubbles and for bubble coalescence and breakup mechanisms are implemented. For predicting particle size and its distribution, S-Gamma (Sγ) model is used. The Sγ model with two-group IATEs are evaluated by comparing local distributions of void fractions and Sauter mean diameters with results of adaptive-multiple-size-group (AMUSIG) models and experimental dataset developed by Schlegel et al., (2012) for model validations. It shows that two-group IATEs with Sγ model predict reasonably accurate flow characteristics of beyond bubbly flow regimes, but also show shortcomings in their accuracies predicting local distributions, which imply that further studies for modeling of interfacial force are needed.