Some New Developments in Rock Mechanics Research and Application

Transcription

1 Some New Developments in Rock Mechanics Research and Application Jian Zhao Wuhan University, 30 October 014

2 Developments in Rock Mechanics Research and Application Research Micromechanics and critical scale Rock dynamics and fracturing Induced seismicity and earthquake Application Earthquake assessment and rock engineering design Shale gas, hot rock geothermal, carbon sequestration Mass mining and rapid excavation

3 Micromechanics and Critical Scale Micromechanics is adopted in all solid mechanics disciplines, it offers better scientific explanation on how materials behave and fail. Different disciplines focus on different scales. ICAMS, 013

4 Micromechanics and Critical Scale The scale of micromechanics are varying depending on the approaches, e.g., molecular dynamics (MD), Critical Distance (CD), and particle flow. In rock mechanics, Critical Distance (CD) and particle flow are usually adopted.

5 Micromechanics and Critical Scale Micromechanics Research: Defining Critical Distance for various rocks; Defining micromechanics constitutive relation; Proving micromechanics constitutive relation is intrinsic; Reconstituting macro behaviour of rock material. Taylor, 009 EFM Taylor, 007 EFM K IC a = ( π σ 0 )

6 Constitutive Laws of Micromechanics Micromechanics and Critical Scale Micro trans- and inter-granular fracture model (QB Zhang, PhD 014) ) ( ) ( 16 ) 3 sin )(sin ( ) ( ) 3 cos )(3cos ( ) ( ) ( ), ( 1 I 1 I II II I I 1 TG d IG d v k v A v k v A v k v A v G v G β β β β β = Zhang and Zhao, 013 EFM

7 Micromechanics and Critical Scale Micromechanics Numerical Methods and Modelling Distinct lattice spring model (GF Zhao, PhD 010) UDEC with cohesive model (T Kazerani, PhD 011) Particle manifold method (L Sun, PhD 01)

8 Micromechanics and Critical Scale Laboratory Testing and Micromechanics Observation 3D X-ray CT for imaging geomaterials at Monash University s rock mechanics laboratory (Courtesy of PG Ranjith)

9 Rock Dynamics and Fracturing Dynamic behaviour of materials, including rock materials, joints and masses is still relatively less understood, primarily limited by observation means. Modified after Zhao et al, 1999 TUST

10 Rock Dynamics and Fracturing Rock Dynamic Research Roadmap

11 Rock Dynamics and Fracturing Observed Rate Dependent Strength of Rock Materials Zhang and Zhao, 014 RMRE I: [10-5, 10 1 ] s -1 II: [10 1, 600] s -1 III: [600, 3000] s -1

12 Rock Dynamics and Fracturing Experimental Techniques of Rock Dynamics Testing Zhang and Zhao, 014 RMRE

13 High-speed Digital Image Correlation with SHPB Rock Dynamics and Fracturing Photron SA1.1 + macro lens ' ' ' ' ZNCC ] ), ( [ ] ), ( [ ] ), ( [ ] ), ( [ m M M i M M j j i m M M i M M j j i M M i M M j m j i m j i g y x g f y x f g y x g f y x f C = = = = = = = Zhang and Zhao, 013 IJRMMS

14 Rock Dynamics and Fracturing Triaxially Compressed Hopkinson Bar (TriHB) Numerical simulation Schematic Zhao and Cadoni, 013 SNF Report

15 Rock Dynamics and Fracturing Rock Dynamic Strength Criteria and Micromechanics Model Normalized strength Conf_pressure=0MPa Conf_pressure=50MPa Conf_pressure=80MPa Conf_pressure=110MPa Conf_pressure=140MPa Conf_pressure=170MPa Intermediate strain rate (Zhao and Li, 000 IJRMMS) High strain rate (Zhang and Zhao, 013 IJRMMS) Normalized strain rate Sliding wing crack model (Li et al, 001 IJNAMG) 000 IJRMMS

16 Rock Dynamics and Fracturing Wave Propagation across Rock Joints and Rock Mass Analytical solution Numerical modelling XF Deng, PhD 013 Experiment Wu, PhD 013

17 Rock Dynamics and Fracturing Analytical Solutions of Stress Wave Propagation in Rocks Virtual wave source method (Li et al, 010 JGR) Displacement & stress discontinuity model (Zhu and Zhao, 011 GJI) Time-domain recursive method (Li et al, 01 GJI) Modified recursive method (Zhu et al, 01 JAG) Thin-layer interface model (Li et al, 013 JAG) Zhu, PhD 011

18 Rock Dynamics and Fracturing Laboratory Experiments Wave Propagation in Rocks Multiple parallel rock fractures Different fracture spacing and orientations Different fracture apertures and filled materials Wu, PhD 013

19 Rock Dynamics and Fracturing Numerical Modelling of Stress Wave Propagation in Rocks Distinct lattice spring model (Zhu et al, 011 C&G) Particle manifold method (Zhao and Sun, 01 G&G) UDEC and 3DEC (Deng et al 01 RMRE, Zhu et al 013 RMRE) Zhu, Deng and Zhao, RMRE Zhao and Sun 01 G&G

20 Induced Seismicity and Earthquake Induced seismicity becomes an increasing concern with energy technologies that involve injection or withdrawal of fluids from deep rocks. Evans, 01 Geothermics Ellsworth, 013 Science

21 Induced Seismicity and Earthquake Research on Induced Seismicity Energy release and and wave generation during joint shearing Effects of joint geometry and roughness on wave generation Induced seismicity due to hydrofracturing Coupling of hydrothermo-mechanics and seismicity Ellsworth, 013 Science

22 Induced Seismicity and Earthquake Laboratory Experiments on Induced Seismicity Measurements of energy and wave generated and transmitted during rock fracturing using 3D Hopkinson bar. Zhao, 009 SNF Proposal Wave generation during plate shearing. Wu and Zhao, 013 EM

23 Induced Seismicity and Earthquake Development of Induced Seismicity Models Joint shearing seismicity model Rock fracturing seismicity model Californian Fault Lab Scale Goebel and Sammis, 013 PAG Wu and Zhao, 013 EM

24 Earthquake Assessment and Rock Engineering Design To be able to assess earthquake potential (by understanding seismic wave generation, propagation and transformation); To have design methodology for large engineering structures in and on rocks subjected to earthquake and dynamics loads. Deng, PhD 013

25 Shale Gas, Hot Rock Geothermal, Carbon Sequestration To develop techniques creating desired fracture network for shale gas and HR geothermal Zhao, 1994 Geothermics system. World s largest (?) high-pressure, high-temperature testing chamber: sample size mm, temperature 450 C, σ1 σ σ3= 350 MPa, multiphase flow. Courtesy of PG Ranjith.

26 Shale Gas, Hot Rock Geothermal, Carbon Sequestration To estimate flow in fractured rock masses (and permeability Of rock materials and rock masses) for various fluids, including at supercritical state; To assess sustainable heat transfer in hot rock geothermal system; To characterize deep subsurface geology and rock fractures for CO confinement. Courtesy of PG Ranjith

27 Shale Gas, Hot Rock Geothermal, Carbon Sequestration To assess and to manage induced earthquakes in shale gas and deep geothermal system. Spatial distribution of identified fault planes and hypocenters of induced seismicity at Basel (Mukuhira et al, 011 GRC).

28 Mass Mining and Rapid Excavation To develop rock mass characterization system for mass caving mining; To develop tools for modelling and managing rock mass movement; To develop better techniques for controlled rock fragmentation. Elmo et al, 013 ASCE IJG

29 Mass Mining and Rapid Excavation To apply TBM for rapid excavation in mine tunnels that usually are of complex geology and varying grounds. Courtesy of AlpTransit

30 Developments in Rock Mechanics Research and Application Acknowledgements ZHANG Qianbing, EPFL, Switzerland, helped with preparation. LI Jianchun, CAS, China, reviewed some of the contents. RANJITH PG, Monash U, Australia, provided information and images. Past and current PhD students on rock dynamics in the last 5 years: ZHAO Gaofeng, UNSW, Australia KAZERANI Tohid, Nottingham U, UK ZHU Jianbo, HK PolyU, HK SUN Liang, PetroChina, China DENG Xifei, China Rail Construction, China WU Wei, Stanford U, USA ZHANG Qianbing, EPFL, Switzerland