青藏铁路修筑后次生不良冻土现象的特征及发展趋势

摘要

The construction of Qinghai Tibet Railway is likely to result in secondary unfavorable phenomena of permafrost, which may cause a lot of damages to the railway. It’s of great Significance to conduct researches on the characteristics and development law of secondary unfavorable phenomena of permafrost after the construction of Qinghai Tibet Railway. In this paper, the secondary unfavorable phenomena of permafrost along the Qinghai Tibet Railway is investigated and classified, and the mechanism, the characteristics and development trend of the secondary unfavorable phenomenon after the construction of Qinghai Tibet railway are studied. There are 18 secondary unfavorable phenomena having direct or potential threat to the Qinghai Tibet Railway. There are only a few secondary unfavorable phenomena related to the roadbed; the phenomena related to the bridge are mainly ice cone and ice mantle, the phenomenon related to culvert is mostly culvert sinking. Future temperature rise causing melting of underground ice near the upper limit of the permafrost may result in lots of secondary unfavorable phenomena that affect the normal operation of the railway.%青藏铁路的修建会形成次生不良冻土现象，次生不良冻土现象会对铁路产生诸多危害。研究青藏铁路修筑以后次生不良冻土现象的特征及发展趋势意义重大。对青藏铁路沿线不同类型的次生不良冻土现象进行调查研究，研究青藏铁路修筑以后次生不良冻土现象产生的机理、发育特征及发展趋势。查明对青藏铁路有直接或潜在威胁的次生不良冻土现象18处，其中与路基有关的次生不良冻土现象较少；与桥梁有关的次生不良冻土现象，主要是桥下形成冰椎、冰幔等；与涵洞有关的次生不良冻土现象，主要有涵洞下沉等。研究表明：未来气温升高导致多年冻土上限附近地下冰大量融化，将会产生诸多次生不良冻土病害，影响铁路的正常运营。