The Influence Of The Groundwater Heating And Seepage On Single Pile's Bearing Characteristics In Permafrost

Along with the development of our country's economy,people in activities to increase the frequency of permafrost zone and permafrost construction area has increased.Since the pile foundation bearing capacity relative to other higher and less impact on the soil around the pile temperature,antifreeze ability and in line with the principle of protection of the permafrost region,reduce damage to the permafrost region's environment.So in permafrost area often used pile foundation.However,due to global warming and human activity in permafrost region frequently cause serious degradation of permafrost and pile bearing capacity is affected.At the same time,due to the extensive use of pile foundation,resulting in significant settlement of pile foundation that permafrost areas have not been found in groundwater and other adverse geological before.Especially the effect of heat and seepage on groundwater reduce bearing capacity of the foundation piles severely.This article is the effect of heat and seepage on groundwater on the ultimate bearing capacity based on the endothermic permafrost.Perforated pipe connected to an external device in the soil model pile can simulate groundwater and its effect on pile foundation in frozen soil region.This article mainly narrative to the following content:(1) In this paper,the underground water in frozen soil is divided into pile bottom water and surface water.We collect data related instruments and correct the data.Then analysis of the effect of seepage and heat or on the mechanical properties of the pile and comparative analysis with no-groundwater simulation model.We get the comparative analysis pile mechanical properties that the seepage and heat efffect then get the following conclusion.Under the same loads,pile strain decreases with increasing depth of pile and when there is effect of heat and seepage on groundwater near the pile strain small variations in the depth direction.Freeze further reduce stress on the groundwater near the pile side, and more distant from the frozen ground is full of stress.Therefore,layer water that has heat and seepage effect compared with that has heat effect pile end resistance are larger and Layer with heat and seepage effect compared with heat effect pile end resistance is smaller.The effect of heat and seepage on groundwater compared with effect of heat on groundwater.It has higher temperatures near the groundwater soil and buried deep in the same pile-soil relative displacement greater.(2) Under the same loading effect,we study the rheology of pile-soil system and how the rheology of pile-soil system effect the mechanical properties of the model pile.Following conclusions:Under the same loads and in the same buried depth,the stress of the pile side decreases with time.The effect of heat and seepage on groundwater compared with the effect of heat on groundwater.The stress of the pile side near the ground water is changed with the time obviously.At the same time,the relative displacement of pile and soil and displacement of pile top is larger and the time is longer.The temperature of the same soil layer is higher,and the time is longer.It is found that the effect of heat and seepage on groundwater has great influence on the rheology of pile-soil and the mechanical properties of the model pile.(3) Under the same loading effect,we study the variation of ultimate bearing capacity of pile foundation under different working conditions and compared with different loading ways.Draw the following conclusion:Under the same loading mode,the pile foundation bearing capacity is higher compared with the effect of heat and seepage on groundwater and groundwater no-seepage.Under different loading conditions,the larger the load time is,the lower the ultimate bearing capacity of pile foundation is.Through the above analysis can be known that the effect of heat and seepage on groundwater not only reduces the ultimate bearing capacity of pile foundation but also increases the rheological properties of frozen soil.It is a serious threat to the safety of buildings and structures on the basis of the pile and the safety operation of the railway in the frozen soil region.Therefore,based on the previous studies,this paper studies the effect of heat and seepage on groundwater on the mechanical properties of the model pile and ultimate bearing capacity of the concrete model pile.At the same time,it provides some reference value for the study of groundwater in the frozen soil region in the future.