ADVANCES IN ROCK- SUPPORT AND GEOTECHNICAL ENGINEERING Shuren Wang Paul C. Hagan Chen Cao AMSTERDAM(cid:129)BOSTON(cid:129)HEIDELBERG(cid:129)LONDON NEWYORK(cid:129)OXFORD(cid:129)PARIS(cid:129)SANDIEGO SANFRANCISCO(cid:129)SINGAPORE(cid:129)SYDNEY(cid:129)TOKYO Butterworth-HeinemannisanimprintofElsevier Butterworth-HeinemannisanimprintofElsevier TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UnitedKingdom 50HampshireStreet,5thFloor,Cambridge,MA02139,UnitedStates Copyright©2016TsinghuaUniversityPressLtd.PublishedbyElsevierInc.Allrightsreserved. Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronic ormechanical,includingphotocopying,recording,oranyinformationstorageandretrievalsystem, withoutpermissioninwritingfromthepublisher.Detailsonhowtoseekpermission,furtherinformation aboutthePublisher’spermissionspoliciesandourarrangementswithorganizationssuchasthe CopyrightClearanceCenterandtheCopyrightLicensingAgency,canbefoundatourwebsite: www.elsevier.com/permissions. ThisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythePublisher (otherthanasmaybenotedherein). Notices Knowledgeandbestpracticeinthisfieldareconstantlychanging.Asnewresearchandexperience broadenourunderstanding,changesinresearchmethods,professionalpractices,ormedicaltreatmentmay becomenecessary. Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluatingand usinganyinformation,methods,compounds,orexperimentsdescribedherein.Inusingsuchinformationor methodstheyshouldbemindfuloftheirownsafetyandthesafetyofothers,includingpartiesforwhom theyhaveaprofessionalresponsibility. Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditors,assumeany liabilityforanyinjuryand/ordamagetopersonsorpropertyasamatterofproductsliability,negligenceor otherwise,orfromanyuseoroperationofanymethods,products,instructions,orideascontainedinthe materialherein. LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailablefromtheLibraryofCongress BritishLibraryCataloguinginPublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary ISBN:978-0-12-810552-8 ForinformationonallButterworth-Heinemannpublications visitourwebsiteathttps://www.elsevier.com/ Publisher:JonathanSimpson AcquisitionEditor:SimonTian EditorialProjectManager:ViviLi ProductionProjectManager:SusanLi Designer:MariaInêsCruz TypesetbyTNQBooksandJournals Biography Shuren Wang, PhD, Professor at School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454003, China. Contact details: þ86 15738529570; [email protected]. His research interests primarily includes the challenging areas of mining engineering, geotechnical engineering, rock mechanics, and numericalsimulationanalysis.Hisresearchpro- jects have been supported by National Natural Science Foundation of China (51474188; 51074140; 51310105020), National Natural Sci- ence Foundation of Hebei Province of China (E2014203012), Science and Technology Depart- ment of Hebei Province of China (072756183), and so forth. He is the recipient of six state- level and province-level awards and the 2015 Endeavor Research Fellowship provided by the Australian Government. He has authored more than 90 academic papers and books. These include 85 articles in peer-reviewed journals, six monographs, and numerous textbooks. He has been authorized four patents and one soft- ware of intellectual propertyrightin China. Paul C. Hagan, PhD, Associate Professor, Head of School of Mining Engineering, Univer- sity of New South Wales (UNSW), Sydney, NSW 2052, Australia. Contact details: þ61 2 9385 5998; [email protected]. His principal research interests include mine geotechnical engineering and other areas in mining engineering. He has more than 30years of experience within the mining indus- try and university sectors. Prior to his appoint- ment to UNSW in 1998, he worked locally and vii viii BIOGRAPHY internationallyinthecoal,gold,andironoresec- in2013.Hehasbeenmainlyinvolvedinrockme- torsinarangeofoperational,management,tech- chanics, mining engineering, and numerical nical, and research roles. He has been the simulation, and has made many breakthroughs principal research investigator of leading pro- at dealing with the problems with complex jects in the rock-cutting research facility. The geological and engineering conditions, espe- research has made significant advances in the cially in large shear displacement by mining application of acoustic emissions in monitoring pressure and other factors on rock bolting and and control of rock-cutting machines and in the anchor support. He has authored more than 20 determination of controlling factors associated academic papers in the research field. withabrasivitytesting ofrock.Hehasauthored 80 peer-reviewed papers, 110 project reports, and three patents. ChenCao,PhD,ResearchFellowatSchool of Civil, Mining, and Environmental Engineer- ing, University of Wollongong, NSW 2530, Australia. Contact details: þ61 2 4221 7945; [email protected]. After he graduated from Xi’an Jiaotong University,Chinawithabachelor’sdegreeinsci- ence, he worked in computer engineering and had nine years of experience in the field of con- structionandmanagement.HeobtainedaBach- elorofEngineeringdegreein2009andreceiveda PhD degree with distinguished award for his PhD thesis from the University of Wollongong Preface There have been significant advances in rock use and interest to the researchers undertaking mechanics and understanding of the behavior various geotechnical engineering and rock me- of rock with developments in science and engi- chanics, teachers and students in the related neering. This has occurred at the same time as universities, as well as on-site technicians. therehasbeengreaterdemandfortheutilization The material presented in this book contrib- of underground space that has in many cases utes to the expansion of knowledge related to pushed the limits in the engineering design of rock mechanics. The authors, through their underground excavations while there has been extensive fundamental and applied research thecontinualneedtoimprovesafetyandreduce over the past decade, cover a diverse range of thecostofexcavation.Itisimperative,then,that topics from the microbehavior of rock and rock research continues which will provide the properties through the interaction of large-scale knowledge necessary to underpin the design rockmassesanditseffectonsurfacesubsidence, anddevelopmentofnewexcavationtechniques. mechanicsofrockcutting,techniquestoimprove Thebooksummarizesandenrichesthelatest the strength and integrity of rock structures in research results on the theory of rock me- surface and underground excavations, and chanics, analytical methods, innovative tech- improvement in approaches to modeling tech- nologies, and its applications in practical niquesused in engineering design. engineering. The book isdivided into six chap- Shuren Wang, PhD ters including such features as Chapter 1: Rock Professor atSchool of Civil Engineering, Henan Testing (Shuren Wang Sections 1e7; Paul PolytechnicUniversity, China Hagan Section 8); Chapter 2: Rock Bolting Paul C.Hagan, PhD (Chen Cao Sections 1e7; Paul Hagan Section AssociateProfessorandHeadofSchoolofMining 8); Chapter 3: Grouted Anchor (Paul Hagan); Engineering,University ofNew SouthWales, Chapter 4: Tunneling Engineering (Shuren Australia Wang); Chapter 5: Slope Engineering (Shuren Chen Cao, PhD Wang); and Chapter 6: Mining Geomechanics Research Fellow at School of Civil, Miningand (Shuren Wang). This book is innovative, prac- Environmental Engineering,University ofWollon- tical, and rich in content, which can be of great gong, Australia ix Acknowledgments The authors are pleased to acknowledge Prof. Youfeng Zou, Prof. Xiaolin Yang, Prof. the support received from various organiza- XiliangLiu,Prof.ZhaoweiLiu,Prof.Zhengsheng tions, including the National Natural Science Zou,Prof.JianhuiYang,Prof.YanboZhang,and Foundation of China (51474188; 51074140; other related people. A number of postgraduate 51310105020); the Natural Science Foundation students, namely Jianhang Chen, Li Li, Chunliu of Hebei Province of China (E2014203012); the Li, Haiqing Zhang, Yan Cheng, Baowen Hu, ChinaScholarshipCouncil(CSC);theHebeiPro- Chengguo Zhang, Peipei Liu, Huihui Jia, Hu vincial Office of Education (2010813124); 2015 Wang, Mengshi Chang, Zhongqiu Wang, Ning Endeavor Research Fellowship and Program Li, Dianfu Xu, Yongguang Wang, Junqing Su, for Taihang Scholars; International Cooperation Huaiguang Xiao, Yanhai Zhao, Chunyang Li, Project of Henan Science and Technology and others assisted in the design, construction, Department (162102410027); Doctoral Fund of and commissioning of the test facility and with HenanPolytechnicUniversity(B2015-67);Open- the experimentation; their contributions to ingProjectofKeyLaboratoryofDeepMineCon- the book are acknowledged and appreciated. struction; Provincial Key Disciplines of Civil The untiring efforts of Mr. Kanchana Gamage, Engineering of Henan Polytechnic University; Dr. Juninchi Kodama, Dr. Mojtaba Bahaaddini, and the School of Mining Engineering, Univer- and Dr. Hossein Masoumi during equipment sity of NewSouthWales. designandlaboratorytestingprogramsaregrate- While it is not possible to name them all, the fullyappreciated.Thanksandapologiestoothers authors are particularly thankful to Prof. Man- whosecontributionswehaveoverlooked. chao He, Prof. Meifeng Cai, Prof. Ji’an Wang, xi C H A P T E R 1 Rock Testing 1. INSTABILITY tosetupverticaldeformationmodeloftheover- CHARACTERISTICS OF A SINGLE lappingroofinthemined-outareas,andputfor- SANDSTONE PLATE wardthecriteriaforevaluatingtheroofstability. Wang et al. (2013c) analyzed the chaos and sto- 1.1 Introduction chastic resonance phenomenon produced in the roof during the evolutionary process of the rock InChina,numerousshallowmined-outareas beam deformation. Meanwhile, some numerical have been left due to the disordered mining by computationmethodswereappliedindiscussing theprivatecoalmines.Itisofimportanttheoret- the mechanical response of rock plate or beam. icalandpracticalvaluefortheroofstabilityeval- Wang et al. (2008a) analyzed the blast-induced uation and disaster forecasting to research the stresswavepropagationandthespallingdamage deformation rupture, instability mechanism, inarockplatebyusingthefinite-differencecode. and failure mode of the rock roof in the mined- Nomiko et al. (2002) researched the mechanical out areas. response of the multijointed roof beams using Thestudiesontheinstabilityoftherockroofin two dimensional distinct element code. Mazor theminingfieldhavebeenamaintopicbothfor etal.(2009)examinedthearchingmechanismof scholars in China and abroad. For example, ac- the blocky rock mass deformation after the un- cording to elastic thin plate theory, Wang et al. derground tunnel being excavated using the (2006)analyzedthefractureinstabilitycharacter- discrete element method. Cravero and Iabichino isticsoftheroofunderdifferentminingdistances (2004) discussed the flexural failure of a gneiss in the mining work face. Wang et al. (2008a) slabfromaquarryfacebyvirtueoflinearelastic analyzed the rheological failure characteristics fracture mechanics (LEFM) and finite element of the roof in the mined-out areas through method(FEM). combining the thin plate and rheology theories. In summary, though many research achieve- Pan et al. (2013) had conducted the analytical ments have been made, the most results still analysis of the variation trend of the bending lack laboratory testing and need to be verified. moment, the deflection, and the shear force of In addition, some numerical calculations were the hard roof in the mining field. This research conducted based on the continuum mechanics, is inclined to adopt traditional analytic methods which could not reflect the spatial heterogeneity to probe into the roof stability. New theories andtheanisotropiceffectoftheroofinthemining and methods have been used in recent years. field.Onlyafewresearchersutilizedthediscrete Zhaoetal.(2010)utilizedthecatastrophetheory element methods to study the macromechanical AdvancesinRock-SupportandGeotechnicalEngineering Copyright©2016TsinghuaUniversityPressLtd. 1 http://dx.doi.org/10.1016/B978-0-12-810552-8.00001-5 PublishedbyElsevierInc.Allrightsreserved. 2 1. ROCKTESTING response of the rock plate, and did not further 1.2.2 LoadingEquipment explorethemicroscopicdamageoftherockplate. TheMTS-851rockmechanicstestingmachine Therefore, a new loading device was developed wasselectedasloadingequipment,andtheload to study the rock-arch instability characteristics was controlled by vertical displacement and of the plate, and particle flow code (PFC) was loading rate was set 1(cid:1)10(cid:3)2mm/s (Potyondy used to further probe into the microscopic dam- and Cundall, 2004). The vertical force and age of the rock plate under the concentrated displacement occurred in the process of the test andtheuniformloading,respectively. and were automatically recorded in real time by a data acquisition system. 1.2 Loading Experiment of Rock Plate As shown in Fig. 1.1, the concentrated and the uniform-loading test sets mainly consisted 1.2.1 Samplesof Rock Plate of three parts. The top was a point-loading for The rock samples used in the test were the concentrated loading or an assembly of the Hawkesbury sandstone, which obtained from steel balls for the uniform loading. The middle GosfordQuarryinSydney,Australia.Thequartz was a loading framework which included four sandstones which contained a small quantity of bolts with nuts connecting the steel plates on feldspars, siderite, and clay minerals were both sides, and the lateral pressure cell was formed in marine sedimentary basin of the placed between the deformable steel plate and mid-Triassic, and located on the top of coal- the thick steel plate so as to monitor the hori- bearingstrata.Thesurfaceofspecimenexhibited zontalforce.Thecapacityofthelateralpressure localredratherthanwhitebecauseofthecontent cell Low Pressure X Type (LPX) was 1000kg. and distribution of iron oxide. The bottom was a rectangle steel foundation, Forthesingle-layerroofofthemined-outareas, the rotatable hinge supports were set on both itcouldbeclassifiedintotwocategoriesaccording sidesoftheloadingframeworktomaintaincon- tothethickness:thethinplateandthethickplate. necting with the steel plates. Andtheroofwasalwaysmadeupofvariouscom- 1.2.3 Acoustic Equipment and Data binations of the thin plates and the thick plates. Thus,accordingtothedefinitionofthethinplate Acquisition System andthethickplateinelasticmechanics,thespec- To monitor the cracks initiated and identify imen size of the thick plate was deigned to the failure location of the rock plate, the USB 190mm(cid:1)75mm(cid:1)24mm (length, width, and Acoustic Emission (AE) Nodes were used in thickness)andthatofthethinplatewasdeigned the test. The USB AE Node is a single channel to 190mm(cid:1)75mm(cid:1)14mm (length, width, AE digital signal processor with full AE hit and andthickness).Thespecimenswereobtainedby time based features. In the test there were four cutting the same sandstone in the laboratory of USB AE nodes being connected to a USB hub School of Mining Engineering, University of for multichannel operation (Fig. 1.2). All these NewSouthWales.Thephysicalemechanicalpa- AE nodes were made in MISTRAS Group, Inc., rametersofrockplateswereshowninTable1.1. in the UnitedStates. TABLE1.1 PhysicalandMechanicalParametersofRockPlates DensityElasticModulus Poisson Cohesion FrictionAngle TensileStrength Compression Name (kg/m3) (GPa) Ratio (MPa) (Degrees) (MPa) Strength(MPa) Sandstone 2650 2.7 0.20 2.8 45 0.95 13.5 3 1. INSTABILITYCHARACTERISTICSOFASINGLESANDSTONEPLATE (A) (B) FIGURE1.1 Loadingexperimentfortherockplate.(A)Concentratedloading.(B)Uniformloading. 1.3 Experiment Results and Analysis MTS loading AE MTS 1.3.1 Characteristicof 3 1 ForceeDisplacement Curve 4 2 Lateral load cell As shown in Fig. 1.3, the vertical force- Power 1US2B h3ub4 AE sensor displacement curves appeared two peaks underboththeconcentrateloadingandtheuni- form loading, and the second peak value is higher than the first one. The thin rock plate A B C D showed the similarity cases in the test with the thick plate; only thepeak values of the ver- FIGURE1.2 MechanicsTestingSystem(MTS)connection tical and the horizontal force were lower than withacousticemissionmonitoringsystemdiagram. that of the thick one. In general, the curves of (A) (B) 6.5 Vertical force 18 Vertical force 6.0 Horizontal force 16 Horizontal force 5.5 14 5.0 4.5 Stage 4 12 Stage 4 N) 4.0 Stage 3 N) 10 Stage 3 k 3.5 k e ( 3.0 Stage 2 e ( 8 Stage 2 c c or 2.5 or 6 F 2.0 Stage 1 F Stage 1 1.5 4 1.0 2 0.5 0 0.0 –0.5 –2 0 2 4 6 8 10 12 0 2 4 6 8 10 Displacement (mm) Displacement (mm) FIGURE 1.3 Forceedisplacement curves under different loading conditions. (A) Concentrated loading. (B) Uniform loading. 4 1. ROCKTESTING the forceedisplacement could be classified as than that under the concentrated loading, espe- four mechanical response stages as follows ciallyatthetwoendsoftherockplate(Fig.1.1B). (Fig. 1.1A): As shown in Fig. 1.3, the loadedisplacement curve showed similarity with the concentrated Stage 1:Therock plate was in the small loading, and the peak value of the vertical force deformation elastic stage. Withthe vertical was greater than that under the concentrated force slowlyincreasing, the vertical loading. displacement grew gradually. On the contrary,thehorizontalforceshowedaslight 1.3.2 Acoustic Characteristicof the Rock- decrease, which was mainlycausedby the Plate Failure slight horizontal shrink of the rock plate during the loading process. As shown in Fig. 1.4, in the beginning of the Stage 2: The rock plate produced a brittle stagetwo,theAEhitsundertheuniformloading rupture and formed the rock-arch structure. were greater than that under the concentrated As the vertical displacement went to about loading,whichwasabout5000and4500,respec- 2.5mm, the vertical force appeared to first tively. In Stage 3 and Stage 4, the AE hits were increaseabruptlyandthendropsharplyina also greater and more evenly distributed under smallinterval,whichindicatedtherockplate theuniform loadingcomparedwith theconcen- producing a brittle rupture. Subsequently, trated loading, which was about 5000 and 3000, the rock-arch structure was formed under respectively. the vertical and the horizontal reaction As shown in the AE location map (Figs. 1.5 forces, and the horizontal force started to and1.6),theresultsshowedobviousdifferences increase. intheinitialcrackpositionandthecracksdistri- Stage 3: The rock-arch structure began to butionoftherockplateunderdifferentloading bear loads and produced deformation. With conditions. When the rock-arch structure went the vertical force increasing, the middle into instability, there also showed the differ- hingepointoftherock-archstructuremoved ences in the damage extent and scope between down, and the two flanks of the rock-arch the two loading methods. All in all, the results rotatedaroundthehingepoint,respectively. of AE hits and location showed the over- Suchkindsofmotionwouldstretchtherock- damage extent and scope of the rock plate archstructureinthehorizontaldirectionand caused by the uniform loading were more squeezed the plate in two sides, and the serious than that under the concentrated horizontal force showed a significant loading condition. growth. Stage 4:Thehinged rock-arch structure 1.4 Numerical Simulations of the becameunstable.Withthe vertical force Loading Test continuously increasing, the middlehinged pointoftherock-archstructuremoveddown 1.4.1 Parameters Calibration ofthe constantly,and whenthe hingedpoint Rock Plate exceededthe horizontal line formed by the The rockplate wastreated as theporousand hinged point and two ends of the plate,the solid material that consisted of particles and rock-arch structure becamethoroughly cement bodies. The forceedisplacement curve unstable. was simulated under the concentrated loading Under the uniform loading, the damage and using the three-dimensional particle flow code fractureextentoftherockplatewasmoreserious (PFC3D).