藏东南察达泥石流的发育特征及对拟建车站的影响

针对藏东南地区普遍发育的泥石流灾害影响川藏铁路车站选址的情况,通过实地调查并结合遥感解译,在查明察达泥石流区域现状的基础上,从泥石流的物质来源、诱发因素、动力因素等成灾条件分析泥石流的形成机理,并计算泥石流的动力学参数。藏东南察达泥石流沟口处的流速为7.63 m/s,静储量及动储量分别为1 519.81万m ³、38.08万m ³,泥石流危险度为中度危险级别,综合确定泥石流为大型-黏性-暴雨型-沟谷型-发展期-中等易发-中度危险泥石流。鉴于察达泥石流直接影响川藏铁路洛隆车站站址安全,为选择合适的线路方案,考虑桥梁和隧道两种不同的工程设置,在穿越泥石流处比选了4种方案;比选结果表明桥梁工程的DK方案桥面不存在淤埋风险,局部或全部堵塞桥涵孔径的风险较低,并便于修建排导槽等防护工程,泥石流引发的风险可控,为最优方案。研究成果可为该地区相似条件下铁路车站站址的选择提供借鉴。

Development Characteristics of Chada Debris Flow in Southeast Tibet and Its Influence on the Proposed Station

In view of the influence of debris flow disaster on the site selection of Sichuan-Tibet railway station, based on field investigation and remote sensing interpretation, on the basis of ascertaining the current situation of debris flow, this paper analyzes the formation mechanism of debris flow from the material source, induced factors, dynamic factors and other disaster conditions, and calculates the dynamic parameters of debris flow. The velocity of Chada debris flow at the mouth of the gully is 7.63 m/s, the static and dynamic reserves are respectively 15.198,1 million m ³ and 38.08 million m ³ and the risk degree of debris flow is 0.5. It is determined that the debris flow is large-scale-viscous-rainstorm-gully-developing-medium-prone-moderate dangerous debris flow. In view of the fact that the mud-rock flow of Chada directly affects the site selection of Luolong station of Sichuan-Tibet railway, considering two different engineering settings of bridge and tunnel, in order to determine the appropriate route scheme, four schemes are selected. The comparison results show that there is no silting risk in the deck of DK scheme of bridge engineering, the risk of partially or completely blocking the bridge culvert aperture is low, and it is convenient to build protective works such as drainage channel, etc. the risk caused by debris flow is controllable, which is the optimal scheme. The research results of this paper can provide reference for the selection of railway station sites under similar conditions in this region.