An Innovative Geomechanical Design Methodology for Underground Mine Excavation Design

Abstract An innovative design methodology so-called "CUED" (Comprehensive Underground Excavation Design) is presented to improve safety, optimise cost, and increase productivity in underground mining excavations. The CUED method proposed in six steps including characterisation, diagnosis of ground behaviour, identifying failure mechanism, design analysis to manage ground behaviour, construction, geotechnical monitoring and design update. A procedure has been defined for each step by determination of input data, processing data and output data, so-called IPO approach. IPO is applied to determine the parameters of the CUED method at each step. Additionally, a new procedure for the design of ground support systems for deep and hard rock excavations considering static and dynamic loading, appropriate design analysis methods, were presented. The results indicated that the proposed CUED method efficiently increase safety and optimise the project's cost and time. The CUED method for geotechnical design purposes in underground mine excavations is illustrated in Figure 1. Intac-t Roc k: -F:k 1 p str -.:4 an' Gooirsgical Conditi--n: Rock Ma.. Compoisitiont Rock Mass Descripti on D Gco tin aily C haracle'1stics. -, In Sitair Stress Cardino-, Massive rack JontIloy Blocky/Folded rock Dr hnegrate SeilMinrl tArt rv 1l,, -7 r Ky Feature Of Underground M,-pt to -x[H King I-rojecl (E-_v-all r .,dr... CondtionDiagnosis & Descriptio the Gmund S1smr Earthquake F -lui:l-1w!Gis Presura 1Temperature Chance, I-lvOding bUNG nrtact Rock Falu tructurallntact StutrlFiur-ae fet pir-is. Ch~c-.ti~nHazard RecognitiontlGeotechnical EniergJuemt Fallure/Fallure Mechanism Failure Indicators: Ground Movement Primary Sigma Secondary Signs eWaults, folds and (at the periphery): (Probably months before): (Probably days/hours before): Local Damage/ joints -Surface cracking -Subsidence eFreq.lenly ground fall iRegional Failure: :Bad ground a Crak opening -Small ground fall -Spalling -Collapse *Unstable sape :Shear movement -Localized signs of stress in eindividual pillar collapse -Cave in Sae Moisture along planes of the form of floor heaving -Pillar yielding or seismic activity -Rock fall Stbl High extraction ratio weakness or vertical *Roof lowering or damage -Rock noises winundlation *angeinpcolour disp acement toudrrud*cvto Emission of gases (in collieries) *I nflow andproertes*Change in water flow -Rock burst *Seismic events Potential failure Potential failiure modes: *Excavation Potential fai