Showing papers in "Tunnelling and Underground Space Technology in 2015"

TL;DR: In this paper, the authors proposed a new longitudinal structural model to consider the shearing dislocation between rings, which can describe the actual deformation mode of a tunnel reasonably and compared with the traditional Euler-Bernoulli beam model based on a field measured longitudinal deformation of a Shanghai metro tunnel.

TL;DR: In this article, a new 3D failure mechanism was proposed using the kinematic approach of limit analysis theory to determine the limit support pressure of the tunnel face, which was composed of four truncated cones on which a distributed force acts.

TL;DR: In this article, the potential risk of undesirable events occurring during tunneling with application of a shield tunnel boring machine (TBM) method is discussed along with the risk analysis which can systematically assess overall risk levels.

TL;DR: In this article, a large-scale geomechanical model test was carried out to explore the surrounding rock deformation and failure mechanisms of such deep roadways, with Zhaolou coal mine in Juye mining area of China as the engineering background, the displacement and stress evolution laws of surrounding rock supported by the pressure relief anchor box beam system were researched.

TL;DR: In this article, a method was presented that the micro-seismic monitoring technology was employed in rockburst monitoring and early warning during construction of the deep-buried headrace tunnels.

TL;DR: In this paper, a test tunnel was excavated at the Mont Terri underground rock laboratory (URL) as part of a long-term research project (Full-scale Emplacement (FE) experiment) aimed at studying the thermo-hydro-mechanical (THM) effects induced by the presence of an underground repository.

TL;DR: In this paper, a three-dimensional (3D) failure mechanism for a circular tunnel driven under a compressed air shield in the case of a dry multilayered purely frictional soil is presented.

TL;DR: In this paper, the authors investigated the failure behavior and instability of the tunnels constructed in the Jinping II hydropower station and concluded that the tunnels should be stable and the majority of the rock mass remains intact even if the applied load is 1.3 P0, where P0 is the in-situ stress.

TL;DR: In this article, a case of closely spaced twin tunnels excavated beneath other closely spaced existing twin tunnels in Beijing, China is presented, where the settlements of the existing tunnels and the ground surfaces associated with the new tunnels construction were systematically monitored.

TL;DR: In this article, the authors performed numerical simulation using Fire Dynamic Simulator (FDS) to estimate the effect of an obstacle blockage according to its location relative to the tunnel floor on the backlayering flow behavior and the critical velocity.

TL;DR: In this article, an experimental investigation of the main factors that influence the sealing efficiency of chemical grouting in a permeated fracture replica is presented, where the authors evaluated and graded by the reduction of water drainage through the fracture after grouting, and the experimental results of the orthogonal arrays show that two most influencing factors on sealing efficiency are the initial water flow speed and the aperture width.

TL;DR: In this article, the PFC3D model was calibrated using the macro-mechanical parameters of the synthetic intact standard cylindrical specimens and macro mechanical properties of a limited number of physical experiments performed on synthetic jointed rock blocks.

TL;DR: In this article, the case history of a 13m wide, 17m high and 40m long service tunnel at Toledo Station, previously constructed in a deep open shaft and belonging to the Line 1 of the Napoli underground network, is investigated.

TL;DR: In this article, a rotational face collapse mechanism is extended to compute critical pressures, in the context of the upper-bound limit analysis, for tunnels in layered (or stratified) ground.

TL;DR: In this article, an experimental program was designed and used to simulate the excavation of three unsymmetrical loading model tunnels with different bias angles, and the change laws and distribution forms of structural stress and surrounding rock pressure were then studied systematically.

TL;DR: In this article, a multiphysics model is presented to describe and predict the coupled THMC behavior of CPB and its evolution with time, which is based on a combination of a set of conservation and constitutive equations.

TL;DR: Earth pressure balance (EPB-) Shields were originally used in fine-grained soils as well as in mixed-grain soils with a content of fine (d) as mentioned in this paper.

TL;DR: In this paper, the development of longitudinal joint opening with bending moment under different axial stress levels, and the longitudinal joint joint opening in the Ultimate Limit State (ULS) was investigated.

TL;DR: Li et al. as discussed by the authors proposed two prediction models for backlayering length and critical velocity in metro tunnel fires, in which the characteristic hydraulic diameter of the tunnel H ¯ was introduced to describe geometrical characteristic of tunnel section.

TL;DR: In this article, the authors used Fuzzy Analytical Hierarchy Process (FAHP) and Probability and impact factors are used in the ideal risk analysis for mechanized tunneling.

TL;DR: In this paper, the authors analyzed the relationship between the rolling force work and thrust force work of the disc cutter, and the meaning of the upper and lower bounds of this equation were discussed.

TL;DR: Wang et al. as mentioned in this paper presented a face support scheme and stability analysis in a case history of opening the pressure chamber for a large-diameter slurry shield tunnel constructed underneath Nanjing Yangtze River.

TL;DR: In this article, an equivalent homogeneous model of coal-rock combination body and its stress state expressions were firstly established based on the strain energy equivalency principle, and the general compression-shear failure criterion of the equivalent model which takes into account the cohesive strength of the interface between coal and soft rock was derived by assuming that the yielded mediums all met Mohr-Coulomb criterion.

TL;DR: In this article, the performance of two types of rock bolts, fully encapsulated rebar and D-Bolt, under combined pull and shear loading were studied in the laboratory.

TL;DR: In this article, the authors evaluated the dynamic responses of buried tunnel in depths of 3.5, 7, 10.5 and 14 m for surface detonation of 1000 kg TNT charge in a surrounding sandy soil.

TL;DR: In this article, the authors proposed a method for assessing bolt reinforcement of the tunnel face in cohesive-frictional soils based on limit equilibrium considerations and can be applied to heterogeneous, layered ground as well as to reinforcement layouts that are arbitrary in terms of the spacing, length, longitudinal overlapping and installation sequence of the bolts.

TL;DR: In this paper, a two dimensional finite element model is presented and validated through comparison with centrifuge test results, both with and without structures, and the model is then used to perform a sensitivity study on the effect of building weight on soil movements and structural deformations.

TL;DR: In this article, the authors present a critical analysis of the design of FRC segments according to the ductility requirements from the Model Code 2010; an alternative approach is proposed that is compatible with the condition found in some tunnels.

TL;DR: In this paper, a large-scale triangular basement with a final excavation depth of 22.8m excavated at two sides of a cut-and-cover tunnel was extensively instrumented in Shanghai soft clay.

TL;DR: In this article, a time independent analytical model based on the strain energy balance in longwall mining is developed to determine the height of destressed zone (HDZ) is taken as equivalent to the combined height of caving and fracturing zones above the mined panel roof induced due to long-wall mining.