Laboratory Testing on Heat Transfer of Blocky Frozen Soils for Backfilling of Tower Foundation along Qinghai-Tibet Electric Transimission Line
Process of heat transfer and the compaction degree of backfills of tower foundation of the electric transmission line in permafrost regions are concerned by engineers and researchers. Generally, some constructions have to be carried out in winter to minimize the thermal distribution to the underlying or surrounding permafrost Thus there exists a problem that the larger blocky frozen soils are always backfilled around the pile foundation. Id order to study the effect of blocky froze soils on the heat transfer between pile and permafrost during the construction of the Qinghai-Tibet Direct Current Grid Interconnection Project (QTDCGIP) in winter, some tests were carried out in laboratory for the larger and porous blocky frozen soils and the thawed soil body. In addition, the thermal conductivity was calculated according to the testing results. Results show that there is convective heat transfer in the porous and blocky frozen soils in winter, which is favorable for permafrost protection. However, backfilling the blocky frozen soil makes it hard to meet the requirement of compaction degree. It has dual effect on the stability of tower foundation depending on the specific situations such as permafrost temperature, ice content, soil type, permeability, hydraulic condition, requirement of safety factor. Results also show that the overall thermal conductivity of the blocky frozen soils is more than that of the thawed soil body. This is because the convective heat transfer occurs in porous and blocky frozen soils. Testing results unveil the process of heat transfer of blocky frozen soils, accumulate and expand the data of the thermal conductivity.
Qinghai-Tibet Plateau electric transmission line permafrost thermal conductivity freeze-thaw
Guoyu Li Qihao Yu Wei Ma Yanhu Mu Xingbai Li
State Key Laboratory of Frozen Soil Engineering Arid and Cold Regions Environmental and Engineering School of Energy and Power Engineering Lanzhou University of Technology Lanzhou, China
国际会议
三峡
英文
3257-3261
2012-05-18（万方平台首次上网日期，不代表论文的发表时间）