The status and degradation causes of patchy permafrost along China-Russia Eastern Gas Pipeline

Frozen swelling and thaw settlement caused by years of permafrost may lead to pipeline deformation and failure. In order to study the status and degradation causes of the patchy permafrost along China-Russia Eastern Gas Pipeline, 16 suspected patchy permafrost regions were investigated and verified by means of the comprehensive investigation method which combines engineering geological drilling, ground temperature test and high-density electrical method. And besides, the data along the pipeline (e.g. climate and forest coverage ratio) were collected to analyze the change trend of each element in the study area in recent years and predict their influences on the permafrost environment. It is indicated that due to the alteration of global climate and many other factors (e.g. the frequent activities of the human), temperature in the Northeast China rises, forest coverage ratio reduces and wetlands disappears, so the original heat balance of the permafrost environment is deteriorated. As a result, patchy permafrost regions along the pipeline are significantly degraded. And correspondingly, the southern boundary of the permafrost in the Northeast China which was delineated in the 1970s moves to the north obviously.