Simple Drapery
2022
ALONG NH-58, CHAMOLI DISTRICT - UTTARAKHAND - India
National Highways & Infrastructure Development Corporation Ltd. (NHIDCL)
ROCKFALL MITIGATION WORKS ON HILLSIDE – HELANG, UTTARAKHAND
Figure-2 Mesh installation (part of simple drapery system)
Figure-3 Installation of bottom anchors
Figure-4 Installation of debris flow cum rockfall barrier
Problem
Helang site is located along NH 58 in Joshimath Tehsil in Chamoli District of Uttarakhand State, India. The surface morphology shows that the moderately fractured weathered rock with vegetation over the slope. The Main Central Thrust (MCT) also passes from this area hence forming the area vulnerable and unstable. The site falls under a highly active seismic zone i.e. zone V and heavy rainfall is usually expected during monsoons. The exposed slope is formed with weathered rock strata that were subjected to rainfall during the monsoon seasons. These rainfall when accompanied by the erosion factors and the steepness, trigger the rock detachment which affects the movement of traffic along this route. The site has been witnessing various slope instability, rockfall and erosion problems and there was a requirement of road widening as well.
Solution
The selection of system had to be resilient to subsurface water, high seismic forces, and steep topography. On the hillside, where there is a rocky strata stretch comprising of fractured rock and bedding planes inclined towards the valley, a simple drapery system is proposed with deep top anchors. Also, at the natural drain locations a rockfall cum debris flow barrier is proposed over the cascade structure. The purpose of providing a barrier is to provide protection against debris flow / rockfall which may happen during rain and thereby mitigating the risk of rock detachments from upslope locations from affecting the infrastructures below. The dynamic rockfall barrier installed is EAD certified. The meshes used in simple drapery system are conforming to existing Indian and international codal guidelines. Additional measures such as erosion control, road side retention, bank side slope protection works etc are adopted separately.
Used Products
Rockfall Barriers
Maccaferri Rockfall Barriers (or Catche Fences) are designed to catch falling rocks and boulders before they fall onto infrastructure, mine haView
Panels
Maccaferri HEA Panels (High Energy Absorption) are the stiffest products within our Mac.RO(TM) Systems mesh range, offering extreme strength at lowView