Post on 14-Apr-2017
transcript
A GEOTECHNICAL INVESTIGATION OF THE 2013 FATAL ROCKFALL
IN ROCKVILLE, UTAH
Carl J. JacklitchAbdul Shakoor
Location
What happened? A large rockfall occurred on December
12, 2013. Approximately 2700 tons of rock fell. Property damage included the house,
garage, and car. 2 fatalities resulted.
Rockfall History
Site Selection
Rockville Bench Supplemental Data
Roadside Supplemental Data
Radio Tower Supplemental Data
Supplemental Sites
Stratigraphy
Stratigraphy
Shinarump Member
Upper Red Member
Shnabkaib Member
Mapping of Discontinuiti
es Includes:
• Orientation• Presence of Water• Roughness• Spacing• Infilling Material• Continuity• Aperture
Laboratory Methods Friction Angle
Dry Density
Resistance to Weathering
Determination of Friction Angle
Test showed • 39° for Upper Red member• 46° for Shinarump member
Actual value used • 35° for Upper Red member• 42° for Shinarump member
Determination of the Rocks Resistance to Weathering
Data Analysis Determine principal joint sets
Kinematic analysis
Rockfall rollout distance
Determination of Principal Joint SetsShinarump member
1. 84, 196 2. 87, 158 3. 87, 229 4. 04, 086
1 2
3
4
Determination of Principal Joint SetsUpper Red member
Moenkopi Principal Joint Sets
1
3
2 1. 84, 228 2. 88, 314 3. 02, 074
Kinematic Analysis Planar Failures
Shinarump member
Joint 1
Joint 2
Joint 3
Bedding
Average Slope Face
Critical Pole
Kinematic Analysis Wedge Failures
Shinarump member
Joint 1
Joint 2
Joint 3
Bedding
Average Slope Face
Critical Intersections
Kinematic Analysis Toppling Failures
Shinarump memberJoint 1
Joint 2
Joint 3
Bedding
Average Slope Face
Critical Pole
Evidence in the Field for Wedge, Planar and Toppling Failures
Largest block that was intact at the fatal site (520 tons) Distance farthest block traveled : 661 feet
House LocationRoad LocationShinarump memberMoenkopi Fm.
Largest block that was intact at the fatal site (520 tons) Distance farthest block traveled : 661 feet
House LocationRoad LocationShinarump memberMoenkopi Fm.
Farthest traveled block (50 tons).Block dimensions: super ellipse 4 (2:3).
Distance traveled of farthest block: 830 feet
Farthest traveled block (50 tons).Block dimensions: super ellipse 4 (2:3).
Distance traveled of farthest block: 830 feet
Other Factors to Consider
2013 Precip. (in) EventsNov high avg low high avg low high avg low high avg low high avg low high avg high sum17 59 46 33 37 35 29 91 67 39 30.19 30.09 29.94 10 10 10 8 2 - 018 63 49 35 37 29 25 79 48 26 30.26 30.17 30.12 10 10 10 12 5 18 019 59 44 30 42 34 28 96 71 47 30.14 30.03 29.97 10 10 10 13 4 16 020 51 40 28 45 38 28 100 87 66 30 29.94 29.89 10 10 1 7 2 - 0.03 Rain21 53 47 41 46 44 41 100 91 68 30.07 29.97 29.92 10 9 2 12 5 17 0.39 Rain , Thunderstorm22 45 43 41 43 38 35 98 80 71 30.1 30.04 29.95 10 9 2 36 15 52 0.36 Rain23 45 42 38 38 37 36 97 82 70 30.15 30.09 30.03 10 9 2 34 19 47 0.26 Rain24 49 40 30 40 36 30 100 88 58 30.22 30.16 30.13 10 9 1 13 3 16 0.01 Rain25 54 39 24 35 30 23 99 81 37 30.37 30.27 30.21 10 10 2 10 2 - 026 59 42 25 35 28 24 97 64 28 30.43 30.36 30.31 10 10 10 16 4 23 027 55 46 36 33 31 28 72 57 43 30.33 30.22 30.13 10 10 7 17 7 22 028 55 44 33 34 31 27 92 62 35 30.25 30.17 30.13 10 10 10 15 8 21 029 56 42 28 35 32 27 99 79 37 30.34 30.29 30.24 10 10 10 9 4 - 030 53 38 23 36 30 22 99 84 51 30.36 30.32 30.26 10 10 7 12 2 - 0
2013 Precip. (in) EventsDec high avg low high avg low high avg low high avg low high avg low high avg high sum
1 52 36 21 34 29 20 99 83 45 30.43 30.35 30.31 10 10 0 8 2 - 0 Fog2 62 42 22 36 29 21 99 75 29 30.32 30.11 29.88 10 10 10 12 3 - 03 57 40 24 33 28 24 99 67 29 29.88 29.66 29.48 10 10 0 22 5 31 0 Snow4 30 20 9 29 16 4 99 74 43 29.99 29.83 29.56 10 8 1 18 11 26 0 Snow5 29 14 -2 12 5 -5 90 73 39 30.05 29.97 29.93 10 10 10 10 3 - 06 34 18 1 19 9 -1 89 71 31 30.15 30.07 30.03 10 10 10 7 3 - 0.027 32 28 23 32 25 17 100 85 69 30.03 29.84 29.71 10 6 0 22 7 34 0 Snow8 27 8 -12 19 3 -16 89 76 51 30.15 30.05 29.89 10 10 10 15 6 20 0.039 25 3 -19 12 -5 -24 88 77 53 30.48 30.35 30.15 10 10 10 8 3 - 0
10 34 14 -6 21 4 -11 91 76 49 30.48 30.35 30.25 10 10 10 9 3 - 011 43 20 -3 23 10 -8 89 63 37 30.42 30.36 30.3 10 10 10 16 3 23 0.0712 50 33 16 27 18 11 96 60 30 30.42 30.3 30.2 10 10 10 16 4 23 013 45 28 11 24 18 10 95 72 40 30.31 30.19 30.12 10 10 10 13 3 16 0
Wind (mph)Temp. (°F) Dew Point (°F) Humidity (%) Sea Level Press. (in) Visibility (mi)
Wind (mph)Temp. (°F) Dew Point (°F) Humidity (%) Sea Level Press. (in) Visibility (mi)
Freeze-Thaw and Ice-wedging
Many gullies act as channels for debris
to flow.
What Areas are Most Hazardous?
Hazard Map
High HazardModerate HazardLow Hazard
High HazardModerate HazardLow HazardCurrent Hazard Boundary
Hazard Map
Possible Mitigation Measures
Rock bolts/anchors Chain mesh on the slope Shotcrete weak units
Always with drains Benches and riprap Move the homes Ditches/Catchments Retaining Walls
Acknowledgments Advisor and Committee
Dr. Abdul Shakoor Dr. Daniel Holm Dr. David Hacker
Utah Geological Survey Bill Lund Tyler Knudsen
Funding Kent State University School of Hard Rocks Scholarship Kent State Student Chapter of SGE Research Scholarship Kent State Student Chapter of AEG Research Scholarship
Special Thanks Mayor Tracy Dutson Robin Dutson Jenny Jasiekiewicz Even Cerveny
Questions?