County Road 17 set for overhaul

Clarion Top News

Wednesday, 19 February 2020 15:34

by Martha Smith

The Jackson County Commission voted and passed several items at the last regular meeting held on February 10, 2020. The smoking and vaping policy was voted on and passed. Smokers on the courthouse grounds will have to move to the gazebo instead of smoking right beside entryways where people coming in and out are breathing the smoke.

County Engineer Jonathan Campbell reported on County Road 17. Campbell had detailed plans for the reconstruction of 450+ feet of roadway that will have to be completely removed up to 17 feet down in order to reach a stable base level to properly address the stability and endurance failure of the road and subsurface. Campbell stated when the geotechnical testing was done in several different sites on that stretch of road, the samples revealed over six feet of layers of pavement, where repairs for the sinking area were mainly layer upon layer of pavement pancaked on top of another. Further testing showed a large pool of fluctuating ground water housed in unstable shale and limestone that could not operate as a dependable load bearing subsurface. Due to the pre-existing instability of the subsurface, the weight of the layers of “repairs” exacerbated the problem, and when the heavy rains came, the ground beneath could not hold the weight of the road and caused a slide. The layers of pavement also revealed there was an underlying problem that was being patched over by simply fixing the surface of the road and not actually addressing the problem itself: the weak subsurface.

After cutting out the road to the desired depth, landslide shoring will go in and will be secured with soil nails. Grouted columns, acting as giant, inverted soil nails, 4 inches in diameter, 18 feet down will go in. Campbell stated during this stage, the side of the mountain will look like a pincushion. The columns will support the load bearing platform that will house the pavement above it, and to ensure the system doesn’t fail in the next deluge, specialized drainage is going in to drain the existing ground water and rain shed that occurs with heavy rains. When the project is completed, that section of road will boast a substantial shoulder, and slides should be a thing of the past.