5040

4744

كارشناسي ارشد

مكانيك سنگ

اصفهان،دانشگاه صنعتي اصفهان، دانشكده معدن

1388

شانزده،127ص.:مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

عليرضا باغبانان، حميد هاشم الحسيني

سعيد مهدوري

88/12/2

عليرضا ياراحمدي بافقي، لهراسب فرامرزي

مهندسي معدن

ID4744

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

Abstract Block failure is one of the most common types of failure in underground excavations Thevolumes of possible unstable blocks are evaluated using different methods such as kinematicanalysis and Discrete Fracture Network DFN methods The forces acting on blocks also areestimated using different analytical and numerical methods such as Limit Equilibrium andDistinct Element Method DEM approaches Probabilistic Kinematics analysis is based onMonte Carlo simulations from the distribution of geometry parameters of fractures DiscreteFracture Network modeling is also based on stochastic representations of fracture system using the probabilistic density function of fracture parameters formulated according to fieldmapping results In order to evaluate the rock block volumes around an excavation using thestochastic DFN approach a large number of DFN realizations should be generated Theproblem in DFN is the calibration for making a representative realization of DFN Using somestatistical tests such as William Watson W W test the most compatible DFN models withmapped fracture in the field are selected for block stability analysis The purpose of this study is to evaluate the unstable block volumes and required supportsystem such as bolt patterns to estimate the model uncertainty of Probabilistic KinematicsLimit Equilibrium PKLE compared with Discrete Fracture Network Distinct ElementMethod DFN DEM analysis which provides a closer representation of reality Quantificationof model uncertainty is one of the critical issues in the design process which is easilyneglected and it has great effect on the safety of project This is the first time that theuncertainties of using PKLE and hybrid DFN DEM approaches is calculated and reported forblock failure analysis around large underground spaces The basic geometry parameters of fractures and also mechanical properties of rocks are takenfrom a large excavated cavern in southeast of Sweden A FORTRAN code was developedbased on the William Watson s W W statistical test The confirmed DFN s by the W W testwas assigned to the DEM model as the geometric basis for the block stability analysis usingUDEC code For the PKLE analysis the commercial software Unwedge which is based on keyblock theory has been used Model uncertainty is calculated using mean difference andvariance ratio of two normal distribution functions The results show that the PKLE underestimates the unstable block volumes The calculatedmean value of unstable block volumes using PKLE is much smaller than DFN DEMsimulation results Although the variance ratio of two normal distribution of required total boltlength from PKLE and DFN DEM methods are equal the mean values of two distributions aresignificantly different which means again that using PKLE method cause a large degree ofuncertainty for block stability analysis around a cavern

عليرضا باغبانان، حميد هاشم الحسيني

سعيد مهدوري

عليرضا ياراحمدي بافقي، لهراسب فرامرزي