柴木铁路多年冻土路基工程措施效果对比研究

Study on the Effect of Different Engineering Measures for Subgrade in Permafrost Regions along the Chaidaer-Muli Railway

为保护多年冻土区铁路路基稳定性,青藏铁路采用了诸如通风路基、块石路基、热棒等一系列主动保护措施,这些措施为保证青藏铁路路基稳定性起到了很好的效果。为研究这一系列主动保护措施在高温、高含冰量沼泽湿地多年冻土区的应用效果,本文选取年降水量较大、地温较高的柴达尔—木里铁路（柴木铁路）江仓段（DK92＋000～DK99＋500）作为观测场,该观测场主要采用了块石路基和热棒两种主动保护措施。通过分析块石路基、热棒路基及无措施路基试验断面2007年至2010年的测温结果,结果表明：在高温、高含冰量沼泽湿地多年冻土区,铁路路基采用块石路基、热棒措施对保护其下部多年冻土较无措施路基作用明显,块石路基和热棒路基试验断面下多年冻土上限抬升、地温降低,同时,对东南—西北向路基采用左侧两排、右侧一排热棒的不对称布设方式起到消除路基下部温度场不均匀性的作用。

To protect the underlying permafrost from thawing and prevent the ground temperatures rising in Qinghai-Tibet Plateau,a series of＂positive cooling＂methods have been applied to keep the stability of the subgrade in cold regions along the Qinghai-Tibet Railway（ QTR）. These measures include ventilated embankment and crushed stone embankment and thermal probe,etc. To estimate the effect of these measures in permafrost regions where the ground surface is much wetter and the ice content is higher,the Jiangcang section（ DK92 ＋ 000 ～ DK99 ＋ 500） of Chaidaer-Muli Railway（CMR） is chosen as the observation site,where the marshes and thermo-karst ponds and depressions are widespread. In this site the crushed stone embankment,thermal probe were applied. According to analysis of the ground temperature monitoring results from 2007 to 2010 in crushed stone embankment,embankment with thermal probe and embankment without treatment,the result indicated that the crushed rocks and thermal probes had an effect on cooling the permafrost,under the test section the upper limit of permafrost raised,the ground temperature lowered. An asymmetric arrangement of thermal probes in southeast-northwest direction with two rows of probes on the left side and one row on the right side can eliminate the heterogeneity of thermal field under the embankment.