Water Tunnel

In this study, an experimental study of new types of polypropylene fibers entitled Barchip (HPP fiber) has been conducted to investigate the usage of this fiber in water tunnel lining. In this study, concrete mixtures with 0.4,0.6 and 0.8 volume percent of HPP fiber and steel fibers were provided. Changes in water absorption, permeability of concrete and chloride penetration depth and abrasion strength were measured relative to the control sample. All tests were undertaken according to ASTM and BS requirements. The results showed that with application of HPP fibers, durability and serviceability of the concrete linings could be remarkably extended.

Free jets have been utilized extensively in many industrial applications. In
general jet fluid discharging from a nozzle develops flow oscillations in the
shear layer. The oscillations will roll up to eventually become toroidal
vortices which increase in size with the axial distance from the nozzle. In
the present work, flow visualization as well as hot-film anemometry have
been employed in order to study incompressible axisymmetric free jet in
moderate Reynolds numbers up to 20,000. The injection of liquid dye or
micro particles associated with a laser sheet turns possible to visualize the
shear layers and, consequently, the vortex formation. Hot-film
measurements into the jet allow determining the flow velocity profile. Flow
visualization is a qualitative tool which a broad view of the flow topology.
On the other hand, hot-film anemometry is a precise quantitative tool but
measurement in only one location at a time. The association of flow
visualization and hot-film anemometry shows very adequate for free jet
studies.

Free jets have been utilized extensively in many industrial applications. In general jet fluid discharging from a nozzle develops flow oscillations in the shear layer. The oscillations will roll up to eventually become toroidal vortices which increase in size with the axial distance from the nozzle. In the present work, flow visualization as well as hot-film anemometry have been employed in order to study incompressible axisymmetric free jet in moderate Reynolds numbers up to 20,000. The injection of liquid dye or micro particles associated with a laser sheet turns possible to visualize the shear layers and, consequently, the vortex formation. Hot-film measurements into the jet allow determining the flow velocity profile. Flow visualization is a qualitative tool which a broad view of the flow topology. On the other hand, hot-film anemometry is a precise quantitative tool but measurement in only one location at a time. The association of flow visualization and hot-film anemometry sho...

In this paper, the hydrostatic interaction between soil and concrete lining of Dasht-e-Abbas pressure intake tunnel has been investigated when the shear strength parameters of the mudstone layers decrease due to the seepage of water to the surrounding media. To evaluate the stability of the tunnel, a two dimensional numerical simulation is developed using the finite element code called PLAXIS and interaction analyses are carried out. The analyses are done in stages to assess the maximum internal forces induced in the lining. The structural stability of the tunnel is evaluated and discussed in this condition. Based on the obtained results, it is noted that for more realistic understanding of the behavior of infrastructures like pressure intake tunnels under various conditions, numerical analyses should also accompany experimental and analytical approaches such as Schleiss method which is described in this paper, especially for tunneling in media that is susceptible to water and ground strength reduction. The numerical analysis results show a considerable increase in the lining internal forces when subjected to the reduction of ground strength. However, the tunnel structure is still stable under the effect of surrounding ground degradation with the constructed lining specifications. Abstract The hydraulic pressure is one of the most important factors in the design of pressure intake tunnels. Since the surrounding media cannot usually resist the high internal pressure of these tunnels, they are usually finished with an adequate lining mostly of reinforced concrete, which is an interaction problem between water, soil or rock and concrete lining. Although reinforcing the concrete lining may reduce the width and number of the developed cracks in the lining, the penetration of water into the surrounding media can still happen due to high water pressure in the tunnel. Thus, it may lead to the development of hydro pressure on the external surface of the lining. There are some theoretical methods that are developed for the design of tunnel lining in this condition. When the tunnel is located above the underground water table, the seeping water may lead to strength reduction of the adjacent soils, particularly when the ground, like the mudstone layers existing in Dasht-e-Abbas region, southwest of Iran, is cohesive and consists of soils that are susceptible to water.