![Page 1: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/1.jpg)
Block Slide/Rockfall on I‐75Campbell County, TN
David Barker, PETennessee DOT
![Page 2: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/2.jpg)
February 26, 2016
![Page 3: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/3.jpg)
Location of Slide
![Page 4: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/4.jpg)
Location of Slide
![Page 5: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/5.jpg)
![Page 6: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/6.jpg)
![Page 7: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/7.jpg)
![Page 8: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/8.jpg)
Portion of the Pioneer 7 1/2 ‘ Quadrangle
![Page 9: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/9.jpg)
![Page 10: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/10.jpg)
February 26, 2016
![Page 11: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/11.jpg)
February 27, 2016
![Page 12: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/12.jpg)
Before and After
![Page 13: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/13.jpg)
February 28, 2016
Sunday after slide
![Page 14: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/14.jpg)
February 28, 2016
![Page 15: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/15.jpg)
Toe of sliding block looking south
![Page 16: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/16.jpg)
Head scarp/top of release joint/high wall
![Page 17: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/17.jpg)
Low angle sliding block
![Page 18: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/18.jpg)
Characteristics of Block• Large – Approximately 90 feet thick/high along near‐vertical release joint
• Near horizontal bedding, dipping toward roadway at 5 degrees or less
• Very low shear strength failure surface; coal seam or highly weathered clay shale
• Water assumed in vertical joint, pressure in joint and along base at time of failure unknown
• Well‐defined sliding surface, shear strength of surface to be back‐calculated
![Page 19: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/19.jpg)
What has changed since the slope was built?Clear cutting along transmission lines that removed undergrowth? Increased precipitation? Progressive weathering of clay shale seam?
![Page 20: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/20.jpg)
How did block travel so far? Momentum?Debris collapsing at release joint pushed outer material over slope?
![Page 21: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/21.jpg)
To stabilize intact material below transmission lines
Anchor and shotcrete projection of exposed joint
Passive anchors/nails and wire mesh over 1:1 slope
![Page 22: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/22.jpg)
Anchors/Nails installed at steeper angles to act in shear as well as tension
![Page 23: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/23.jpg)
Analysis and Assessment of Failure Mode(s)Sliding block movement along failure surface of known location, orientation and extent, back‐calculated shear strength and assumed water conditions
![Page 24: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/24.jpg)
Analysis Tools SNAP‐2Excerpt from memo dated March 15
![Page 25: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/25.jpg)
Analysis ToolsRuvolum for analysis of material after weathering, shallow surface
Excerpt from memo dated March 15
![Page 26: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/26.jpg)
March 3, 2016 ‐ Removal of front of sliding block
![Page 27: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/27.jpg)
March 4, 2016 ‐ Removal of slide debris from slope
![Page 28: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/28.jpg)
March 8, 2016, excavation of shaly clay at top of slope
![Page 29: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/29.jpg)
Debris removal continues
![Page 30: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/30.jpg)
March 10, 2106, southbound lanes open
![Page 31: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/31.jpg)
March 15, 2016, release joint exposed/intercepted
![Page 32: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/32.jpg)
Slope on March 18, 2016
![Page 33: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/33.jpg)
Preparing to anchor and shotcrete lower slope 3/23/16
![Page 34: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/34.jpg)
Northbound lanes reopened after construction of temporary lanes in median and removal of the least stable debris 3/26/16
![Page 35: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/35.jpg)
Sandstone layers near top of slope, note dip of strata
![Page 36: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/36.jpg)
March 28, insertion of anchors for combination shotcrete/wire mesh covered slope
![Page 37: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/37.jpg)
March 29, grouted anchors for combination shotcrete/wire mesh covered slope
![Page 38: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/38.jpg)
Anchors after grouting, prior to shotcreting
![Page 39: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/39.jpg)
Drain strips, wire mesh, #4 bars, plates and nuts installed
![Page 40: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/40.jpg)
Slope after shotcrete application
![Page 41: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/41.jpg)
Removal of slide debris from lower slope nearing completion April 13, 2015
![Page 42: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/42.jpg)
Drilling for anchors in upper 1:1 slope
![Page 43: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/43.jpg)
Installation of nails in shaly clay, note closer spacing
![Page 44: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/44.jpg)
Placement erosion control matting prior to placement of wire mesh, May 23
![Page 45: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/45.jpg)
Anchored grade beam installed in front of wall as alternative to continuing to excavation along release joint
![Page 46: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/46.jpg)
Grade Beam in Place
![Page 47: Block Slide/Rockfall on I Campbell County, TN...Mar 23, 2016 · February 26, 2016. Location of Slide. Location of Slide. Portion of the Pioneer 7 1/2 ‘ Quadrangle. February 26,](https://reader033.vdocuments.us/reader033/viewer/2022052014/602bfd595badea381f198bdb/html5/thumbnails/47.jpg)
QuestionsHow rare (or common) is this?
Can these sites be identified 20 to 50 years after construction and mature vegetation has been established?
What do we do about them? Flatten the slopes?, Install drains? Installed anchored grade beams?
What have other DOTs encountered?