title of the thesis - Department of Geology - Queen's University

More documents

Recommendations

Info

$Fayek & Kyser 2000 uraninite fractionations.pdf - Queen's University$

propagation as confining stresses are relaxed. Beyond this exists a damage zone where yielding occurs with some localization along failure planes. High stresses occur on the periphery of the yield zone as the rock transitions from a fractured rock mass into a stronger, more intact rock mass. This parallels the rock mass model of an inner yield zone, damage zone and outer intact zone as discussed in Chapter 3. When the faults are weaker than the rock mass, right-lateral slip is induced on the Plum Shear Zone and often on the Return Air Raise Shear Zone to the south of the excavation. Remote to the excavation, no slip occurs along these or other discontinuities. The deflection of stress around the excavation may act to enhance the normal stress, and thus the frictional resistance, along discontinuities remote from the excavation, preventing slip. Closer to the excavation maximum principal stresses are reduced but oriented at a low angle to the Plum Shear Zone, increasing the shear stress on the fault and instigating slip in both plastic and elastic models. This, however, occurs within the yield zone and may not contribute to seismogenic slip. 4.7.1 Synthesis: Stress, Seismicity and Structure The relationship between structure and seismicity in the Creighton Deep is intimately linked to stress. The spatial distribution of seismicity closely corresponds to zones of high stress. A comparison of seismicity and stress is shown in Figure 4.25. This similar distribution supports the idea of the presence of a yield zone in proximity to the excavation where low stress and no seismicity occurs; a damage zone of high stress where dense seismicity occurs, and beyond this an intact zone where low to intermediate stress is associated with little seismicity, as discussed in Chapter 3. Both the distribution of stress and seismicity appear to be modified to align with the strike of the 118-System shear zones, but not within the shear zones themselves. The exception is 102
seismic Cluster 1, which corresponds to an area of elevated modelled differential stress but with background levels of modelled maximum stress (Fig. 4.25). Geological evidence of degradation is difficult to observe in underground conditions due to limited access and enhanced support in proximity to the excavation. However, drilling supports this degradation process. Drill cores in proximity to the main excavation (in the proposed yield zone) are heavily fractured and highly degraded (Dave Andrews; pers. comm., 2009). The damage zone has already extended below the base of the mine at the 7940 ramp, which is also evident from drilling and excavation as the mine is progressively deepened (Dave Andrews; pers. comm., 2009). Slip along mine-scale shear zones has not been identified as a failure mechanism during seismic or stress analysis. Instead, slip along existing fractures and cracking of intact rock have been demonstrated to be plausible alternative mechanisms to fault slip. Mapping zones of fracture reactivation and crack initiation using modelled stresses suggests that existing fractures without cohesion may be reactivated and new cracks can form in zones of high stress. Though modelled stresses are not elevated enough to lead to fracture interaction and coalescence, clustering of seismic events signifies the onset of yield as the rock mass is seismically weakened, which supports observations made using seismic event parameters in Chapter 2. 103
Page 1 and 2:
THE INFLUENCES OF STRESS AND STRUCT
Page 3 and 4:
esulting in increased stress to the
Page 5 and 6:
Table of Contents Abstract.........
Page 7 and 8:
4.6.1 Fracture Reactivation........
Page 9 and 10:
List of Figures Figure 1.1: Locatio
Page 11 and 12:
Figure 3.23: Preliminary stress inv
Page 13 and 14:
Figure B11: Events between Jan 1, 2
Page 15 and 16:
List of Tables Table 2.1: Geologica
Page 17 and 18:
Chapter 1 Introduction 1.1 Backgrou
Page 19 and 20:
Figure 1.1: Location of Sudbury and
Page 21 and 22:
Chapter 2 Geological Assessment of
Page 23 and 24:
ack breccia and sediments later dep
Page 25 and 26:
Murray Fault, the principal fault o
Page 27 and 28:
2.2 Local Geology of Creighton Mine
Page 29 and 30:
B West East B’ Figure 2.4B: Longi
Page 31 and 32:
Table 2.2: Fault systems within the
Page 33 and 34:
Table 2.3: Summary of Fault Charact
Page 35 and 36:
Figure 2.6: (A) Damage to shotcrete
Page 37 and 38:
Figure 2.7: (A) The 1290 Shear Zone
Page 39 and 40:
Figure 2.8: Images of (A) the 400-E
Page 41 and 42:
Figure 2.9: (A) Photograph of the c
Page 43 and 44:
Figure 2.10 (A) Shear foliation, in
Page 45 and 46:
Figure 2.11: Thin sections of the F
Page 47 and 48:
(Fig. 2.12B). Reduction of quartz g
Page 49 and 50:
2.3.11 Late-Stage Fractures The you
Page 51 and 52:
overprinting (Cochrane, 1991; Couls
Page 53 and 54:
Table 2.4: Summary of Proterozoic t
Page 55 and 56:
Both of these inferred stress direc
Page 57 and 58:
are, at this time, in the process o
Page 59 and 60:
Microseismic events of this subset
Page 61 and 62:
3.2.1.2 Seismic Energy (E o ) and S
Page 63 and 64:
3.2.1.4 Stress Parameters Stress pa
Page 65 and 66:
located events were removed from cl
Page 67 and 68: Figure 3.7: Detected seismicity cor
Page 69 and 70: Table 3.1: Event characteristics in
Page 71 and 72: Table 3.3: Summary of relevant para
Page 73 and 74: ) Damage Zone The rock mass in the
Page 75 and 76: quadrants of dilatation and compres
Page 77 and 78: Figure 3.12: Lower hemisphere equal
Page 79 and 80: mechanism shows that over 57% of th
Page 81 and 82: Figure 3.16: Classification of prin
Page 83 and 84: Figure 3.18: Contoured P-axis, B-ax
Page 85 and 86: Figure 3.20: Distribution of double
Page 87 and 88: This parameter reflects the magnitu
Page 89 and 90: Figure 3.23: Preliminary stress inv
Page 91 and 92: Figure 3.25: Equal area stereonet s
Page 93 and 94: Figure 3.27: (A) Maximum principal
Page 95 and 96: 4.2 Numerical Methods Phase 2 and U
Page 97 and 98: Stress-strain relationships are use
Page 99 and 100: Rock mass failure is governed by th
Page 101 and 102: Figure 4.5: (A) Model for tectonic
Page 103 and 104: The zero cohesion and low friction
Page 105 and 106: Figure 4.9: Model of yielding for C
Page 107 and 108: Figure 4.11: Model of differential
Page 109 and 110: Figure 4.14: Model of maximum stres
Page 111 and 112: stress field model. There is little
Page 113 and 114: clustering are indications of rock
Page 115 and 116: Figure 4.23: Contoured domains of s
Page 117: Figure 4.24: Fracture initiation th
Page 121 and 122: contains energetic events and is no
Page 123 and 124: preferentially oriented fracture pl
Page 125 and 126: methodologies employed are of value
Page 127 and 128: References Alcott, J. M., Kaiser, P
Page 129 and 130: Galkin, V., Mungall, J. (2005). Str
Page 131 and 132: Mungall, J. E., & Hanley, J. J. (20
Page 133 and 134: Appendix A Geological Maps and Samp
Page 135 and 136: A.2 Level Plans with Sample Locatio
Page 137 and 138: Figure A3: 7400 Level, modified for
Page 139 and 140: Figure A5: 7680 Level, modified for
Page 141 and 142: Figure A7: 7940 Ramp, modified from
Page 143 and 144: MICROSEISMIC EVENTS Source Radius A
Page 145 and 146: 2006 Event Frequency with Depth 600
Page 147 and 148: B.2 Spatial Distribution of Seismic
Page 149 and 150: Figure B11: Events between Jan 1, 2
Page 155 and 156: Cluster 1 Source Radius Asp. Radius
Page 157 and 158: Seismic Moment 10.0 9.5 9.0 8.5 8.0
Page 159 and 160: 143 Peak Velocity Parameter -2.5 -2
Page 161 and 162: B.4.2 Temporal Distribution of Clus
Page 163 and 164: 147 Static Stress Drop 5.0 5.5 6.0
Page 165 and 166: B.4.3 Temporal Distribution of Clus
Page 167 and 168: 151 Static Stress Drop 4.0 4.5 5.0
Page 169 and 170:
Frequency-Magnitude Relation for Cl
Page 171 and 172:
P-axis B-axis T-axis 155 Fault Plan
Page 173 and 174:
P-axis B-axis T-axis Fault Plane 1
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
D.1.1: Case 1 Models Figure D1: Cas
Page 181 and 182:
Figure D3: Case 1, elastic models s
Page 183 and 184:
A B C D Figure D5: Case 1, plastic
Page 185 and 186:
A B C D Figure D7: Case 1, plastic
Page 187 and 188:
D.1.2: Case 2 Models A B C D Figure
Page 189 and 190:
D.1.3: Case 3 Models A B C Figure D
Page 191 and 192:
D1.4 Tectonic Loading Models Figure
Page 193 and 194:
D.2 Discussion of Phase 2 Models El
Page 195 and 196:
Staged models were created in which
Page 197 and 198:
Figure D17 (A) Elastic model showin
Page 199 and 200:
Figure D19 (A) Elastic model showin
Page 201 and 202:
• Similar damage zones surroundin
Page 203 and 204:
; ;================================
Page 205 and 206:
change jmat=1 range 0,1564.64 0,156
Page 207 and 208:
crack (845.579,718.676) (787.063,57
Page 209 and 210:
;===plum=== crack (0,355.2371429) (
Page 211 and 212:
crack (866.14,726.44) (838.2,737.61
Page 213 and 214:
crack (838.2,737.616) (815.848,771.
Page 215 and 216:
crack (815.848,771.144) (815.848,78
Page 217 and 218:
;===== define sub block ===========
Page 219 and 220:
E.9 S3:S1 Model for fracture reacti
Page 221 and 222:
yval= abs(z_syy(zi)) xyval= abs(z_s
Page 223 and 224:
and rearranged to , (Equation F4) .
Page 225:
Such that , (Equation F19) I is the
show all

title of the thesis - Department of Geology - Queen's University

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?