关键词: 冻结粉土, 成桩工艺, 温度场, 承载力, 桩侧摩阻（冻结力）

Abstract:

As the most suitable form of foundation in frozen soil engineering， pile foundation mainly adopts three types of piles， plugging pile， the static pressure pile and the bored pile. Because of the different pile formation process， the difference between the frozen ground and the pile foundation itself is different. In order to research on the influence of different pile formation technologies on the permafrost foundations and bearing behavior of foundation piles. The introduction dead load model test of the single pile under -1.5 ℃ conditions which is carried out to analyze influence laws of the ground temperature field， the ultimate bearing capacity of single pile， the axial force of pile shaft and the friction resistance on impact of using different pile formation technologies in the frozen silt. It is found that the bored piles has a violent disturbance to the ground temperature field， so the temperature of pile side is higher， and large amplitude of changes in ground temperature. With the refreezing of the soil around piles， the ground temperature is gradually decreased. The cooling rate of the bored piles is the biggest； In terms of bearing capacity， the ultimate bearing capacity of the two types of bored piles is about 12.8 kN ， and the static pressure pile is 11.6 kN， the ultimate bearing capacity of plugging pile is the minimum， which is only 2/3 of the bored pile； And compared the corresponding settlement of the piles of four piles by using different formation technologies under different load conditions， and reflecting the difference caused by using different formation technologies on the pile foundation settlement； With the increasement of load on pile top， the friction resistance and the tip resistance gradually play. Due to the temperature of 1/3 of pile is lower which makes the friction resistance larger. The temperature was least near the depth of 10 cm， so the friction resistance reaches the maximum value. Compared the transmission of the axial force along the pile body under the load of 5.6 kN. It is found that the static pressure piles are more easy to transfer the load to the deep foundation in the frozen soil； Drawn the rheological curves of four piles by using different formation technologies. It is found that the long-term bearing capacity of the two kinds of bored piles is about 6 kN， the static pressure pile is 4.5 kN and the plugging pile is 3.5 kN. The test result shows that the different pile formation technology has caused some extent of difference in the long-term bearing capacity of the piles in the frozen soil.

Key words: frozen silt, pile formation technology, ground temperature field, bearing capacity, pile side friction （freezing force）