The Jorabat Shillong Expressway Limited (JSEL), Guwahati has been entrusted four laning & development of Jorabat – Shillong section by NHAI. The challenge was to convert an existing 2-lane highway into a four-lane expressway in the terrain that is hilly and dense. The region also receives the highest rainfall and part of the highway is among the wettest regions in the country.

Before giving solution, consultant visited the site. It was observed that the particular section was in cutting and the cutting has exposed rock faces that were intact in some locations and fragmented in few locations. The exposed rock surface on the sloping face is always subjected to disintegration by various causes such as plant action, thermal expansion, wind, freeze and thawing action of the pore water, hydrostatic pressures etc. The disintegration of parent rock leads to formation of rock pieces, boulders and debris and they easily detach from the bed rock and will slide over the slope. Such fall of rock happens catastrophically at random locations without giving prior warning. During monsoon seasons, the situation gets worsen that rock falls may become vary frequent. This called for rockfall protection solutions.

• Before a drapery system was installed, the slope was thoroughly scaled and the anchors were installed.
• Unless the drapes were rolled out from the top of the slope, a staging area at the slope base was required to
  prepare the drapes for installation.

Equipment used for installing a drapery system includes the following:

• Drill for installation of mesh anchors. A hand-held drill with a man lift or a track drill was typically used for the anchor installation.
• Crane was used for placing the wire mesh

The majority of maintenance on a drapery system consists of removing trapped material in order to prevent overloading of the wire mesh. Limited vegetation growth within the mesh area did not reduce the effectiveness of the mesh, but large shrubs or trees may cause problems and be removed. The toppling of trees may cause both global and localized failure.

• All items were checked at the time of delivery. Items were moved to the site using cranes.
• Before the installation of any materials, the crest area and slope face were prepared.
• The crest was cleared of all significant or dense vegetation (see right) to promote easy and safe access and to enable simple manipulation and placement of mesh etc.
• Following the crest clearing the slope face was cleared by the process of “de-scaling”. This typically included removal of loose rocks, soil, and excessive vegetation growth from the slope face This work was overseen by