Flexible Retaining Barriers for Prevention of Avalanches on National Highway NH-1A

Defence Science Journal

Arun Chaudhary¹  Gursharan Singh¹  Vinay Chaudhary¹  Gurpreet Singh¹ 

[1] Snow & Avalanche Study Establishment, Chandigarh

关键词: Avalanche danger;    snowcover;    avalanche hazard;    avalanche control structures;    flexible retaining baniem;    avalanche prevention;    snow rakes;    snow bridges;    snow nets;    swivel posts;    terrain investigation;   

DOI  :  

学科分类：社会科学、人文和艺术（综合）

来源: Defence Scientific Information & Documentation Centre

【 摘 要 】

"An avalanche hazard Call be reduced byactive and passive methods. In an active method, which is a veryeffective, avalanche control structures are used to mitigate theavalanche danger. These structures can be installed in any of the threezones of an avalanche, viz., formation zone, middle zone and run-outzone. In the formation zone, avalanche can be controlled by supportingstructures/retaining barriers, which are installed in the formation zonewith a view to prevent formation of an avalanche. Their placement inthe formation zone with proper arrangement and layout helps inpreventing fracture in the snow mass. The basic concept lies inconverting the shear and tensile stresses in snow into compressivestresses which can be conveniently sustained by the snowcover. Suchsupporting structures/retaining barriers can be categorised into rigidand flexible types of structures. Snow rakes and snow bridges arecategorised as rigid structures, whereas wire rope nets are categorisedas flexible structures. The Snow & Avalanche Study Establishment,Chandigarh, had developed snow nets in 1988-89, which were installed atD-10 avalanche site on north portal of Jawahar tunnel, Jammu-SrinagarHighway (NH-1A). These nets were designed considering the snow forcesacting in the direction parallel to the slope only. Hence, the movementof the swivel post was restricted in one direction only. However,detailed scientific studies carried out for retaining barriers over thelast seven year's have revealed that two types of failures occur inthese nets. First, a major failure was noticed in hinge joint of swivelpost, and second, a failure was noticed in the foundation of the uphillanchor. To overcome these failures, the swivel post joint has beenredesigned as articulated ball and socket joint to cater for omnidirectional movement to the swivel post, and the uphill anchorfoundation has been strengthened by providing the reinforcement. Thispaper deals with the concept of flexible retaining barriers, includingcriteria for height of structures, their layout, terrain investigationrequired and also considers the snow pressure for designing variouscomponents of snow nets.

【 授权许可】

Unknown