青藏高原清水河多年冻土区铁路路基沉降变形特征研究

通过埋设在青藏铁路路基中两个断面内的6条沉降观测管3 a来的地基沉降变形资料,研究了高原多年冻土区铁路路基的沉降变形特征,分析了填筑铁路路基对下伏多年冻土融化变形的影响。研究表明,由于受到填筑路基时赋存在路基填料内的热量的影响,铁路路基下伏多年冻土上限在施工初期会有一个明显的下移沉降,铁路路基也随之有一个较大幅度的工后下沉变动,随着时间的推移,路基下降速率会逐渐下降,但在短时间内不会停止下来,而且由于太阳辐射和路基边坡形状的影响,路基向阳面与背阴面的变形有较大的差别,且在近南北向展布的路基上表现最为明显。

SETTLEMENT CHARACTERICS OF QINGHAI-TIBETAN RAILWAY EMBANKMENT ON PERMAFROST SUBGRADE IN QINGSHUI RIVER REGION OF TIBET PLATEAU, CHINA

This paper examines the settlement characteristics of the embankment of the Qinghai-Tibetan railway on the plateau permafrost subgrade in Qingshui region of the Tibet Plateau,China.The settlements were measured using six pipes buried in the embankment for three years during and after the construction of the embankment.The results show that the settlements in the plateau permafrost beneath the embankment have four features :(1) the slowness settlement is the principal part of the embankment distortion which consists of the freezing-expanding and the melting-sinking;(2) Most of the embankment settlement occurred in the plateau permafrost beneath the embankment which has hardly settlement;(3) the focus of deformation distortion is located beneath the shoulder of embankment where is exposed to the Sun;(4) the geological feature of the plateau permafrost beneath the embankment affects the settlement feature of embankment straight.