摘要
对于寒区公路工程 ,查清冻土工程地质条件是至关重要的 .利用地质雷达和探孔来研究多年冻土的分布 ,为路基设计和处理提供依据 .研究结果表明 ,黑北段分布有 17段岛状多年冻土 ,总长度为 3 .165km ,主要分布于沼泽化湿地、泥炭层和草炭层极为发育低洼地带 .多年冻土上限约 1.5～ 2 .0m ,多年冻土厚度 3～ 6m .主要发育有多冰冻土、富冰冻土、饱冰冻土 .多年冻土地温较高 ,热稳定性较差 ,多年冻土处于强烈的退化状态 .
Engineering geology appraisement is the key of highway design aiming at roadbed stability in the regions with degrading permafrost. Especially in the regions of sporadic permafrost, exploring its spatial distribution is necessary. Permafrost is in the process of intensive degradation due to climate warming. However, thermal disturbance of engineering activities will accelerate the degradation. Degrading permafrost mainly presents in the areas with swampy wetland or peat in the Xiao Hinggan Mountains. Peat can delay the degradation owing to insulating, and removing the peat will accelerate the degradation, disadvantageous to roadbed stability. Permafrost distribution, formation and its engineering geological conditions must be studied in detail for the highways in cold regions. However, drilling is difficult to exactly explore sporadic permafrost distribution. Therefore, sporadic permafrost distribution is always surveyed by geological radar and exploring holes in order to provide the base of roadbed design and disposal. Exploring results show that the section from Heihe to Beian is located in sporadic permafrost regions, where there are 17 permafrost sections, 3.165 km in total length. The mean annual ground temperature is higher and the thermal stability is poor in the section. Sporadic permafrost presents in the swale swampy wetland with peat and surface water. Permafrost distribution and development has an obviously difference in different topographic units under the effect of conversing-temperature, vegetation, soil, aspect, surface water and ground water. Generally, permafrost mainly appears in ditch valley. No permafrost takes place in high slopes and mountains. Seasonally frozen and thawed depth is about 1.5 m to 2.0 m, with the maximum of about 2.5 m. Permafrost thickness is about 3 to 6 m, with the maximum is about 9 m. Ground ice appears in massive, micro-layered, layered cryostructures near the permafrost table.
出处
《冰川冻土》
CSCD
北大核心
2001年第3期312-317,共6页
Journal of Glaciology and Geocryology
