جستجوی مقالات مرتبط با کلیدواژه "tunnel lining" در نشریات گروه "عمران"

Many studies have been performed on fiber reinforced segmental lining for years, which is to improve some of the weak material properties of Segmental lining. Fiber-added reinforced concrete (FRC) applications have become widespread in areas such as, tunnel shells, concrete sewer pipes, and slabs of large industrial buildings. Usage of FRC in load-carrying members of buildings having conventional reinforced concrete (RC) frames is also gaining popularity recently because of its positive contribution to both energy absorption capacity and concrete strength. The paper is focused on the mechanical properties of the designed structural steel fiber reinforced concrete (SFRC), which are important for the capacity of the tunnel lining segments and their damage during manipulation. Generally the segments are more loaded during tunnel lining installation (long term load is lower). The realized investigation was focused on SFRC with various types of fibers, such as steel fiber and synthetic fiber. The use of fiber reinforced concrete for the Golab tunnel segments was examined, but for the highly loaded big rings with high bending moments and normal forces, a high amount of bar reinforcement is necessary

Tunnelling in a saturated soil often produces a long-term interaction between the tunnel lining and the surrounding soil. Inltration and external pore-water pressures are often important factors that must be considered in the lining design. Development of pore water pressure may accelerate leakage and cause deterioration of the lining. This can be particularly troublesome to structural and functional components of the tunnel and can often lead to structural failure. In this paper, an axi-symmetric circular tunnel under the groundwater table is modeled using nite dierence software, and dierent conditions, such as an impermeable tunnel, a permeable tunnel and a lining drainage system with varying permeability are investigated. The structural behaviour of the lining and ow through the tunnel lining were modelled using a combination of beam and solid elements. The eects of tunnel parameters, such as depth and diameter and variation of underground water levels, on the eectiveness of the lining drainage system are examined. Moreover, the deterioration of a drainage system caused by clogging is investigated and the importance of giving careful consideration to lining permeability and hydraulic boundary conditions is highlighted. As a result of coupled analysis, a lining drainage system in a shallow tunnel with small diameter is more ecient, and eective drainage conditions reduce pore water pressure loads, which decreases the bending moments and tensile stresses of the tunnel lining. By performing a parametric study for a tunnel with dierent lining permeabilities, a design curve to evaluate pore water pressure loads on the lining has been proposed. It is shown that the hydraulic deterioration of the drainage system signicantly develops a magnitude of pore water pressure load on the tunnel lining.