Title of article :
Evaluation of the Heading Confinement Pressure Effect on Ground Settlement for EPBTBM Using Full 3D Numerical Analysis
Author/Authors :
Haghi، Amir Hossein نويسنده National Iranian South Oilfields Company, Ahvaz, Iran Haghi, Amir Hossein , Asef، Mohammad Reza نويسنده Geology Department, Kharazmi University, Tehran, Iran Asef, Mohammad Reza , Taheri، Ali نويسنده Zaminfanavaran Geotechnical Consulting Engineers (ZAFA), Esfahan, Iran, Taheri, Ali , Mohkam ، Mohsen نويسنده Ecole National des Travaux Publics de L’Etat (ENTPE), Laboratoire Geomateriaux, France Mohkam , Mohsen
Issue Information :
دوفصلنامه با شماره پیاپی 0 سال 2013
Abstract :
Ground settlement is often the most serious concern when tunneling under an old city with numerous historic
monuments. A successful engineering design under these conditions would require getting the most out of the
ground strength parameters and avoiding any weakening maneuver throughout the operation. Knowing that surface
settlement is highly affected by tunneling parameters in EPB shield tunneling lead us to estimate the optimum values
for the machine heading pressure with the lower amount of the ground settlement in fragile structure of the old city
for the Esfahan Subway Project. Tunnels were dug underneath some of the most prominent historical sites along the
path of the project. To improve precision and efficiency in tunneling operation, at the first step, tunnel heading
confinement pressure is calculated by using an advanced 3D mathematical approach based on the limit equilibrium
theory. Then, a promoted 3D finite element model is developed, taking into account the tunneling procedures and
the designed heading confinement pressure from the first step. Settlements were pre-calculated and the surface
displacement was checked at all sensitive locations. At the third step, settlement is estimated by exerting executed
face supporting pressure to the tunnel face and the concluded amounts for displacement are compared with the
outputs of extensometers. This comparison leads us to check the reliability of calculated settlements and the
accuracy of the designed tunnel heading confinement pressure. Furthermore, evaluating the relation between
extensometer outputs and executed tunnel face pressure at the points of extensometers stations validates the
assumption that the safe face supporting pressure causes least surface displacement. Although the minimum pressure
occurred in short term fluctuations, this approach confirms the sensibility of settlement with the least executed face
supporting pressure.. It is also found that higher executed face supporting pressures could reduce the tunnel face
stability. Therefore, documentation of appropriate software facilitates design procedures. Yet a further achievement
of this study concerns effective decision implementations under strictly limited.
Journal title :
International Journal of Mining and Geo-Engineering
Journal title :
International Journal of Mining and Geo-Engineering