川藏公路尼洋河下游宽浅游荡型河段水毁路基防护试点工程

Prevention Works of Roadbed Water-Damage along Meandering Channels in Tibet ——A Case Study in Sichun-Tibet Highway in the Lower Niyang River

川藏公路K4257+710～K4258+205位于尼洋河下游宽浅游荡型河段。通过对该段路基水毁的形成因素、水毁特征及防护工程水毁的分析,再通过野外路基防护工程模型试验,建立适合该段路基的冲刷保护计算公式:hs/h=1 3(B/r)0 391(h/d)0 141Fr0 947exp(-0 16m-0 11(σg-1 3)),确定了路基水毁永久性防护工程的方案。在保证足够的基础埋深的基础上,提出了一种新的防护工程结构,为青藏高原宽浅游荡型河段水毁路基防护工程建设提供了示范。

The lower Niyang River is meandering with wide and shallow channel, where water-damage is very serious to roadbed in the K4257+710～K4258+205 section of Sichun-Tibet Highway. This paper analyses the forming factors and characters of the damage, and puts forward an empirical formula: h_s/h=1.3 (B/r)^(0.391) (h/d)^(0.141)Fr^(0.947)exp(-0.16m-0.11(σ_g -1.3)), for estimation of the washing out. This provides a design criteria for the durable control works, basing on the given buried depth of roadbed. All of these give a pilot study for the construction of roadbed prevention works in Tibet.