Exploration and Mining
Hassan Bakhshandeh Amnieh; Amirhossein Rostami; Kurosh Shahriar; Hamid Chakeri; Masoud Cheraghi Seifabad
Abstract
When a tunnel passes through weak soil with different conditions, or there is a thin layer of soil on top of the tunnel, the mass of soil or rock must be stabilized. In addition, an excavation method must be chosen and applied in order to control the amount of subsidence and convergence which are among ...
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When a tunnel passes through weak soil with different conditions, or there is a thin layer of soil on top of the tunnel, the mass of soil or rock must be stabilized. In addition, an excavation method must be chosen and applied in order to control the amount of subsidence and convergence which are among the most significant factors in excavation a tunnel especially in urban area, since the soil between the tunnel and the ground moves due to changes in the shape of the tunnel through excavation, and progression of these movements toward the ground is manifested in subsidence of the surface structures. Therefore, in order to choose an excavation method based on the conditions of the project site, providing a decision-making model is essential. The ultimate goal is to select the most suitable subway tunnel excavation method among all available alternatives based on some determining criteria for Isfahan subway tunnel (Line 1). These criteria along with Multi-Criteria Decision Making (MCDM) models helped prioritize suitable alternatives. This model was designed based on technical, financial, executive, social, political and geo-mechanical features of the research site each of which subsumes a number of criteria. On the one hand, alternatives include Open Shield (full face) method, Slurry method, NATM method and excavate twin tunnel with TBM method which are used in the model. Finally, alternative D (excavate twin tunnel with TBM method) was selected as the best alternative of the site in both AHP(D=0.225) and TOPSIS(D=0.676391).
Exploration and Mining
H. Bakhshandeh Amnieh; Amirhossein Rostami; Kurosh Shahriar; Hamid Chakeri; Masoud Cheraghi Seifabad
Abstract
Abstract In the urban tunneling project, one of the most important parameters to be considered is the subsidence level. Metro tunnels are one of the most important urban transportation infrastructures. Due to shallow depth of drilling, the most important factors to prevent the maximum subsidence and ...
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Abstract In the urban tunneling project, one of the most important parameters to be considered is the subsidence level. Metro tunnels are one of the most important urban transportation infrastructures. Due to shallow depth of drilling, the most important factors to prevent the maximum subsidence and subsequent damage of surface and subsurface structures are deformation control and shear forces. The various methods of estimating the subsidence are divided in three categories, namely; Empirical, analytical and numerical methods. In this research, according to the geotechnical conditions of the study area using the data collected from the monitoring during the excavation of twin tunnels of metro by TBM, the empirical methods for the subsidence ( s=A_2+s_max/2 ), the maximum subsidence (s_max=A_1-A_2 ) and the inflection point (ⅈ=x_0 ) are presented by using Boltzmann function for Isfahan twin metro tunnel. Keywords: Subsidence, Maximum subsidence, Inflection point, Empirical Method, Analytical Method, Numerical Method, TBM.
