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Alireza Talebinejad Hamid Chakeri Mahdi Moosavi Yılmaz Özçelik Bahtiyar Ünver Mehmet Ali Hindistan 《Arabian Journal of Geosciences》2014,7(9):3913-3923
Underground structures are currently widely used and are built as urbanism develops. The interactions between perpendicularly crossing and parallel tunnels in the Tehran region are investigated by using a full three-dimensional (3D) finite difference analysis with elastic-plastic material models. Special attention is paid to the effect of subsequent tunneling on the support system, i.e., the shotcrete lining and rock bolts of the existing tunnel. Eventually, as the tunnels are excavated at certain levels, the interaction between the tunnels will certainly have a significant influence on both stress distribution and consequently deformations. Since multilayer tunneling is a three-dimensional phenomenon in nature, 3D numerical solutions must be utilized for analyzing effect of perpendicularly crossing tunnels at various levels. As Tohid twin tunnels and Line 7 pass beneath the Line 4 metro tunnel, changes in stress distribution, deformations, and surface settlements are studied for various conditions and the results are presented in this paper. Consequently, it is shown that there is a significant interaction between tunnels that necessitate certain preventive measures to maintain a stable tunneling operation. 相似文献
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Nowadays, due to urbanization and population increase, need for metro tunnels, has been considerably increased in urban areas. Common characterization of urban area tunnels is that they are excavated in very shallow depths and soft ground. In such excavations, main challenge for tunneling is low bearing capacity and easy deformation characteristic of the ground. Tunnel face instability and the potential surface settlement are the most hazardous factors that should be considered in all tunneling methods applied in urban areas. Incorrect estimation of the maximum surface settlement value can lead to irreparable damages to the buildings and other nearby structures. There are several published relationships concerned with field measurements and analytical solutions to estimate the amount of the maximum surface settlement value due to tunneling. These relationships are not precise for calculating the aimed values. Therefore, providing accurate equations for estimation of these values is certainly useful. First purpose of this study is to determine the effective parameters such as geotechnical factors (cohesion, internal friction angle, density, Young’s modulus and Poisson’s ratio), and engineering factors (tunnel depth, tunnel diameter and face support pressure) on the maximum surface settlement value. In this study, three metro project constructions namely Istanbul, Tehran, Mashhad in the Middle East were chosen. FLAC3D (Itasca Consulting Group 2002) was used for detailed numerical analysis. The second aim is to present better equations in estimating the maximum surface settlement-based actual data set from several tunnel projects and numerical modeling. The results from the new estimation equation are compared with results of empirical and field observations. The maximum surface settlement values obtained from the new equation have good agreement with the actual results for three different metro case studies. 相似文献
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Natural Hazards - Extreme maximum (Tx) and extreme minimum temperature (Tn) frequency distributions during summer and winter for blocked conditions were analyzed within Turkey during the period... 相似文献
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Mehmet Ali Hindistan Abdullah Erhan Tercan Bahtiyar Ünver 《International Journal of Coal Geology》2010,81(3):139-150
The coal quality is an important aspect of coal mine planning. This paper presents a case study in which an underground coal mine is faced with severe penalty cost because it does not consider in situ coal quality control at all. To help short term planning of the coal production the mean calorific values of the blocks inside the production panels are estimated by kriging. The estimated calorific values are compared with those obtained from actual production. The ratio of the calorific values of actual production to estimated values is found to be 0.73 in average due to adverse effect of dilution on the quality of run-of-mine coal. This study reveals the importance of geostatistical block modelling in short term mine planning. 相似文献
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