青藏铁路110kV输电线路冻土桩基模型试验研究

MODEL TEST STUDY ON PILE FOUNDATION OF 110 kV TRANSMISSION LINE OF QINGHAI—TIBET RAILWAY IN FROZEN SOILS

根据相似理论的基本原理确定了青藏铁路110 kV输电线路冻土桩基室内模型试验的相似准则与试验方法,并据此研究了上拔、下压和倾覆荷载的独立与组合作用下冻土地基和桩基间冻结强度、桩基承载力、桩侧冻土抗力以及冻土地基系数随深度变化的比例系数等参数的变化规律。试验结果表明,温度是冻土桩基承载力的主要影响因素,其试验成果可为该输电线路桩基础设计提供参考。

According to similarity theory,the principles and methods of the frozen model test for pile foundation of the 110 kV transmission line of Qinghai—Tibet Railway in frozen soils are determined.Then the freezing strength between frozen soils and pilest,he bearing capacity of pile foundation and the frozen soil pressure on piles under the independent and combined actions of the uplifting,lowering and toppling loads are studied.The results indicate that the freezing strength between frozen soils and piles,the bearing capacity of pile foundation and the frozen soil pressure on piles will all dramatically decrease with the increase of temperature.So,temperature is the determinative factor of the bearing capacity of pile foundation.Some suggestions on the selection of foundation types and the design optimization of pile foundation of transmission line in frozen soils are proposed.