Whereas, the curve of artificial permafrost table in the roadbed and natural permafrost table in the ground not disturbed declines year by year with annual increasing rate of temperature averaging 0.02 ℃.
在年平均气温增长0.02℃的条件下，试验段内冻土人为上限和未受路基影响的冻土天然上限均逐年下降；
Ground Temperature Method & the Method for Calculating the Depth of Permafrost Table
计算多年冻土上限深度的地温法
The permafrost experimental segment is located in the region of Qingshui River along Qinghai & Tibet Railway, with an average elevation of 4470 m, mean annual ground temperatures between-1.40 ℃ and-0.46 ℃ and permafrost table in the range of 1.5 to 3.5 m.
青藏铁路清水河多年冻土试验段，平均海拔4470m，冻土年平均地温为-1.40℃～-0.46℃，冻土上限为1.5～3.5m，2001年9～11月施工。
It is a positive correlation between the embankment height and the uplift value of artificial permafrost table in a reasonable range of height.
合理高度范围内，路堤高度与人为上限抬升值之间正相关；
It shows that construction berm has limit effect on the ground temperature characteristics of embankment such as artificial permafrost table, annual mean ground temperature and thaw bowl, however, the thaw depth well increase and annual mean ground temperature will rise.
研究结果表明：设置护道对人为上限、年平均地温及融化盘等路基地温特征影响有限，但融化深度、年平均地温均表现为增大趋势；
The paper briefly discusses the main factors influencing the permafrost table and the main methods of determining the upper limits for the permafrost table in Qinghai-Tibet Plateau.
简述了影响高原冻土上限的主要因素以及确定冻土上限的主要方法，探讨了冻土上限变化的计算公式。
But, even the permafrost table has highly raised the annual thermal imbalance of soil and the process of temperature rise, it is disadvantageous for the thermal stability of permafrost.
对于高温多年冻土来说，尽管多年冻土上限也得到了较大幅度的抬升，但升温过程和土体年收支的不平衡都在朝着不利于多年冻土热稳定方向发展。
The coarse-grained soil as embankment fill can meet the basic condition of heat transfer theory to uplift artificial permafrost table.
粗颗粒土作为填料可以满足路堤人为上限抬升的基本传热学条件；
In order to understand the impact of artificial permafrost table to the subgrade deformation of the Qinghai-Tibetan Highway in degenerating process, three experimental observation fields were set up to measure the deformation of the road being built in south of the Tanggula Range.
为研究青藏公路多年冻土人为上限在退化过程中对路基变形产生的影响过程和程度，在唐古拉山以南选择了3处具有代表性的路面进行了为期2a的路面变形观测。
The suitability of the thermal offset and permafrost table temperature model generally adopted abroad is discussed in this paper, and the model is applied to the eight frost soil sections along the line of the Qinghai-Tibetan Highway, where ground temperature is monitored.
主要讨论国外普遍采用的温度位移和多年冻土顶板温度近似模型的适用性，并在青藏公路沿线8个冻土地温监测断面中应用模型进行计算。
The calculation results show that pavement types have positive influence on thermal regime in permafrost embankments, and concrete pavement can effectively decrease pavement temperature, delay falling velocity of permafrost table, and protect the permafrost under embankments effectively.
结果表明：路面类型对冻土路基温度场有着重要影响，水泥路面的采用可有效地降低路面温度，延缓冻土上限下降速率，从而可以有效保护基底多年冻土；
After asphalt pavement having been constructed in permafrost regions, permafrost thermal regime and permafrost table under roadbed will undergo a change.
多年冻土区修筑沥青路面后，引起了路基下多年冻土上限、多年冻土热状态等变化。
Simulation results verify that insulated board can effectively protect the heat from transferring into the foundations, and the frozen table is always around the lower bottom of the boards; the position of the frozen table with insulated boards is higher than that of without; the embank- ment formation has a better effect on the center of embankment, the shoulder and toe of the roads than others; after consideration of the construction effect, the best lay out of the insulated boards is higher than the position of natural ground surface to 0.3-0.6 m; this formation of the embankments is the right effective constructer to be used in the permafrost on the Qinghai-Tibet railway.
通过数值模拟可知：保温板能够有效地阻止热量由路基面向下传入地基中，使0℃等温线始终在保温板底层；复合路基多年冻土上限的位置要比无保温板时的高；该结构形式对路基中心、路肩和坡脚下的多年冻土上限抬升的综合效果更好；考虑施工条件后，复合路基在保温板铺设距离天然地面之上0.3~0.6 m对于路基稳定性最为有利；该路基结构形式为青藏铁路多年冻土区路基的理想结构形式，有利于克服全球变暖的影响。