变暖背景下砾石换填对多年冻土区机场跑道下地温场的影响OA北大核心CSTPCD

Under a warming climate,frost hazards have become increasingly more frequent in permafrost regions in North of Northeast China.In the studies of engineering design,construction and operation/maintenance in permafrost regions,research on the ground temperature fields of engineered foundations is key to analyzing and solving problems due to frost hazards.In this paper,the finite element method was used to investigate the impacts of refilling of clean gravels on the ground temperature fields of runway foundation soils,and to predict the temperature fields of the foundation soils under the runway over a 30-year period of runway operation.The results indicate that the gravel refilling of runway foundation soils can significantly increase the maximum-depth of seasonal frost-penetration(MSF).The horizontal thermal influence of the refilling on the MSF of the foundation would extend laterally to about 30 m at each side.Then,by comparing the changes in ground temperature fields of the foundation structures with different refilling depths(1.5(top of the refill)to 3.5,4.5,5.5 and 6.5(bottom)m),it is found that the rate of change in MSF would gradually decrease when the bottom of refilling depth reaches 4.5 m.Finally,by simulating the values of MSF under no-refilling and different filling depths for different climate warming rates over the next 100 years as indicated by the Sixth Assessment Report(AR6)of the Intergovernmental Panel on Climate Change(IPCC),it is found that by 2100,the MSF under the SSP2-4.5 scenario would be 1.63,1.86,1.84,1.84 and 1.84 m,respectively.Therefore,when using the refilling of clean gravels to mitigate frost hazards of runway foundation soils,the refilling bottom depth should be no smaller than 4.5 m.At the same time,the well-managed construction and good maintenance of drainage and/or barrier facilities for surface and subsurface waters near the runway should be considered in cases of abnormally rainy and/or snowy summers and falls.This study is helpful to understand the influences of gravel refilling on the thermal state of permafrost foundation soils,and can provide an important scientific basis for solving the problems of frost heave and thaw settlement of runway foundation soils in permafrost areas.