Spatio-temporal Evolution Characteristics and Influencing Factors of Permafrost Underlying Gonghe-Yushu Expressway Subgrade
To analyze the spatio-temporal evolution characteristics of permafrost underlying expressway subgrade on the Qinghai-Tibetan Plateau,and to explore the influencing degree of new roadbed pavement structure and natural environmental factors on the degradation of subgrade permafrost,the study took the southern boundary section of Gonghe-Yushu expressway crossing permafrost area for an example.ArcGIS was utilized to conduct in-depth excavation on the publicly available climatic,topographic,and drill-core data in the study area to analyze the influence of different elevations,slopes,slope orientations,normalized vegetation index ( NDVI),mean annual temperature ( MAT),mean annual ground temperature ( MAGT),mean annual precipitation (MAP),mean annual humidity (MAH) and new roadbed pavement structure on the spatio-temporal evolution characteristics of permafrost underlying expressway subgrade.The result indicates that the influencing degree of new roadbed pavement structures on the degradation of perennial permafrost underlying roadbed is 1.23 times greater than that of natural environmental factors.The permafrost degradation along the route from 2011 to 2019 shows some spatial heterogeneity.The main factors affecting permafrost degradation rate in permafrost fast and low degradation zones are MAGT and MAH respectively.The main factor affecting permafrost degradation rate in the whole study area is MAGT.The perennial permafrost degradation rate of expressway subgrade from 2011 to 2019 is 36 cm/a,which is 8 times and 2.32 times of Qinghai-Tibet railway and Qinghai-Tibet highway respectively,and 1.83 times of G214 Gonghe-Yushu expressway in the same area and during the same period.It is suggested that the expressway alignment in the permafrost area of Qinghai-Tibet Plateau should be selected according to the positional distribution of no permafrost distribution,high altitude negative slope with permafrost endowment,low altitude negative slope,high altitude sunny slope,and low altitude sunny slope.When the route direction is set to the latter 3 cases,the subgrade needs to be taken corresponding of permafrost protection measures.
road engineeringspatio-temporal evolution patterngeological information atlaspermafrostArcGIS
NETL
NSTL
万方数据
