فهرست مقالات Tunnel design

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  1 - Analysis of Circular Reinforced Tunnels by Analytical Approach
  Ahmad Fahimifar Masoud Ranjbarnia
  This paper addresses the problem of quantifying the mechanical contribution of rockbolts installed systematically around tunnels (regularly spaced around the tunnel) excavated in rock masses. Assuming that the mechanical contribution of grouted rockbolts is that of incr چکیده کامل

  This paper addresses the problem of quantifying the mechanical contribution of rockbolts installed systematically around tunnels (regularly spaced around the tunnel) excavated in rock masses. Assuming that the mechanical contribution of grouted rockbolts is that of increasing internal pressure within a broken rock mass, a new procedure for computation of ground response curves for a circular tunnel excavated in strain softening material and then reinforced with systematically active grouted rockbolts is presented. In this work, the equation of the ground response curve for a tunnel which has been reinforced with passive grouted rockbolts is also derived. The proposed model allows one to take into account the effect of the distance of the bolted section to the tunnel face, the effect of increasing rockbolts spacing, the influence of increasing pretension load in calculating of the ground response curve, and the effect of increasing the cross-section area of rockbolts. The results show that decreasing rockbolts spacing increases the support system stiffness rather than preloading of them. پرونده مقاله
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  2 - Design and Manufacturing of Jet to free Stream Simulator to Experimental Study of Interaction of Oblique Jet in Crossflow
  Moslem Ahmadi Mohamad Hojaji Saeed Toolani
  The study of interactions of jet into cross flow at different longitudinal and transverse angles of jet was studied. The following components were designed and constructed: a low velocity wind tunnel to produce the uniform flow, a flat plate with a traverse injection sy چکیده کامل

  The study of interactions of jet into cross flow at different longitudinal and transverse angles of jet was studied. The following components were designed and constructed: a low velocity wind tunnel to produce the uniform flow, a flat plate with a traverse injection system to simulate the jet injection, and a spatial rake to measure the total pressure. The tests were carried out at longitudinal (α) and transverse angles (β) of 60, 75, and 90 degrees and a velocity ratio of 2.5. The free stream and jet stream velocities were set at 20 and 50 meters per second and were constant for all the tests. Results showed that flow field development could be controlled through injecting oblique jets. Decreasing β caused the following results: 1) improved the effects of injection along the mixing direction, 2) increased jet penetration along the plate width direction, and 3) increased the flow wake. In addition, decreasing α led to a slight increase downstream of the nozzle, but failed to produce a significant change in to total pressure coefficient. پرونده مقاله