Show r PREVENT SLIPPING OF MOUNTAIN ROADS I IAn IAn An Interesting chapter In the history his his- tory ory or of the development de of mountain roads Is the story ot of how highway engineers h have he e conquered the sprIng slides In the mountains of West Vieginia Vie VIr- ginia Roads or traits tracts In these mountaIn sections showed the constant tendency to slip down a little toward the stream bottoms each spring sluing In the days of earth roads this did not matter so much a few tew hours hours' work by the road gang soon had the highway In repair again But after the country began to buIld paved highways the problem became became be- be came much more Pavement surfaces became cracked twisted and wa warped e I The first step was to determine the cause of the trouble Boring Into th the hillsides s revealed that the centers were rock above the rock was a layer layero o of clay generally five to ten feet In thickness and between the two was a ala la layer er of shale fire clay or soapstone ThawIng left leC the clay porous when the spring break up came Melting snow and rain saturated It until the whole mass became mushy The water seeped down to the layer of soapstone forming a greasy slide down which the clay crept slowly carrying with dt It trees fences telephone poles and highways Breaking up the shale and soapstone soap soap- stone by blasting tailed failed to to prevent the slipping ot of the top layer A wall built on the solid rock and heavy y enough to resist the pressure of the earth above seemed to be the only alternative but this would have ha entailed entailed en- en tailed an exPense expense greater than any state could bear Finally It was decided to experiment expert expert- meat ment with a light wall anchored to the underlying rock with concrete posts rn In building such n a wall a steam well drill working through a steel well casing was used d to drill a hole through the earth and five feet Into the solid rock below Concrete reinforced reinforced rein rein- forced with steel rods was was poured inside in- in no side the well casing to form a solid post nearly nearl- as high as the wall was to be A A. trench was then dug down downto to the rock fock the welt well casing removed remo from rom the post and the trench backfilled backfilled back back- filled with gravel to the top of the slippage e plane A concrete wall was i built on grael footing enca the posts which an anchored It firmly More than a mere anchorage was r required however howe to support the load ontI pushing against the wall so other similar posts were er built on on time the uphill uphill up- up hill sIde ot of the roadway Four one one- Inch bars encased In concrete connected connect connect- ed the upper posts with the wall and formed n a tie whIch prevented pre the wall overturning This Timis method solved the problem of If the engineers Sometimes concrete posts alone have been heen sufficient to hold the earth and the walls have been unnecessary 01 Oc- Oc Occasionally the u underlying shale has been solid enough nough to hold wooden plies piles driven above e the road to protect protest pro pro- test It from the push of the slidIng hill Many paved roads ha have e been saved since this system uns inaugurated by Vest Virginia in n 1017 |