For the two types of shield tunneling such as Slurry and EPB shield the stability of tunnel face depends on the prevailing support pressure. The support pressure at the tunnel face has to be applied to a value that gives as well sufficient safety against a collapse of the tunnel face as the against uplifting. The paper aims at a better understanding of the mechanics of face failure for those la...

In this paper, a systematic approach is presented for optimal design of tunnel support lining using two-dimensional finite element analysis models of soil-structure interaction developed in ABAQUS software and the Modified Colliding Bodies Optimization (MCBO) algorithm implemented in MATLAB environment. This approach is then employed to study the influence of variable geometrical and geo-mechan...

the ground reaction curve (grc) is a vital component of the convergence-confinement method, which possesses many applications in the underground space designs. it defines a relation between the tunnel wall deformations and the ground pressure acting on the tunnel walls. generally, grc includes descending and ascending branches. according to many researchers, the descending branch trend for the ...

The role of road-tunnel ventilation has changed during the last decades. While in former years tunnel ventilation was responsible for providing an acceptable environment for tunnel users passing through the tunnel during normal operation conditions [30], nowadays the support of rescue conditions during a fire is dominating. The introduction of the fire case into the ventilation design resulted ...

The ground reaction curve (GRC) is a vital component of the convergence-confinement method, which possesses many applications in the underground space designs. It defines a relation between the tunnel wall deformations and the ground pressure acting on the tunnel walls. Generally, GRC includes descending and ascending branches. According to many researchers, the descending branch trend for the ...

The Konjsko tunnel is an integral part of the Zagreb-Split-Dubrovnik highway, section Prgomet-Dugopolje. It consists of two tunnel tubes having 1326.0 and 1133.8 meters in length. The greatest overburden amounts to 150 m. This paper presents geotechnical measurement results and back numerical analyses. Back numerical analyses in combination with geotechnical measurements enable safer and more r...

background: the present study assesses independent predictors of clinically important traumatic brain injury (citbi) in order to design a prognostic rule for identification of high risk children with mild head injury. materials and methods: in a retrospective cross-sectional study, 3,199 children with mild traumatic brain injury (tbi) brought to emergency ward of three hospitals in tehran, iran...

A utility tunnel is defined as an underground structure containing one or more utilities, permitting the installation, maintenance and removal of the systems without the necessity of making street cuts or excavations. These underground facilities contain all essential utilities serving large urban areas collected together in a tunnel; therefore they are an inviting target for sabotage or vandal...