بررسي امكان سنجي حفر ايستگاه متروي ميدان نقش جهان به روش زيرزميني

چكيده انگليسي :

Feasibility Evaluation for Excavation of Naghshe Jahan Square Subway Station by Underground Method Morteza Abdi Cherlo m abdicherlo@mi iut ac ir Date of Submission 2011 10 26 Department of Mining Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Hamid Hashemolhosseini hamidh@cc iut ac ir Masoud cheraghi cheraghi@cc iut ac irAbstract In recent years in reaction to the increasingly urgent usage of urban spaces the excavation ofunderground spaces has been developed One of the most challenging projects faced by tunnel engineeringis construction of subway stations as large underground spaces in shallow ground and soft surrounding soilin urban areas Subway stations are of those underground spaces that have a great importance indevelopment of urban transportation In attention to excavation of these underground spaces in urban areaswith weak formations stability analysis and support design of such underground spaces in constructionstages and long term stability must be evaluated In this thesis Naghshe Jahan Square Subway Station thatis located in Isfahan Iran has been simulated by FLAC3D geomechanical finite difference method FDM This station is located under important historical structures therefore the ground displacement induced byexcavation of the Naghshe Jahan Square subway station and the settlement on the ground surface are veryimportant Many of such problems are affected by selective excavation method For these reasons in thisthesis different underground excavation methods and their construction methods have been studied andevaluated The best excavation method can be selected in different geology conditions and availableequipments with investigation and comparison between different excavation methods such as sequentialexcavation method cut and cover method concrete arch pre supporting system enlargement shieldtunneling method multi face shield construction method microtunneled arch method and large diametercurved pipe roofing method that have been investigated in this study Sequential excavation method sequential excavation method with middle columns and large diameter curved pipe roofing method havebeen used in this thesis and the results that derived from numerical analysis of these methods are compared For stability analysis of Naghshe Jahan Square Subway Station different support systems have beenevaluated using different stability criteria and then the appropriate support system has been selected Forexcavation of urban underground spaces in soft ground beneath water table there are some methods Assuch of these methods we can mention dewatering chemical consolidation and grouting freezing closedface tunneling machines and compressed air that all of these methods have some problems and benefits About compressed air method this method is still frequently employed and it is important that engineersunderstand its effect upon both labour force and the environment in orde to minimize its adverse effects likehazard to health of workers at high pressures risk of damage to old structures and risk of suddendecompressions and about ground freezing problems we can express surface access required causesdamaging heave of surface in some soils and this method is very expensive to maintain freeze The fact thatour cities are often sited on flood plains means that soft ground tunneling techniques are frequentlyemployed but the presence of underground water table means that special techniques must be adopted tomaintain stability of the ground during the construction hence compressed air and ground freezingtechniques have been utilized in simulation of subway station Numerical analysis results have beencompared with the permissible settlemet of surface structures and eventually the appropriate excavationmethods and support systems have been selected

عبدي چرلو، مرتضي

بررسي امكان سنجي حفر ايستگاه متروي ميدان نقش جهان به روش زيرزميني

فضاهاي زيرزميني , نشست زمين , روش حفاري ترتيبي , هواي فشرده , انجماد زمين , روش اجراي سيستم پيش نگهدارنده با استفاده از لوله هاي قوسي , FLAC3D