Model On Frost Heave Of Soil And Studies On Frost Heave Damage Prevention For Canal With Double Membranes Considering Thermal Effect Caused By Water Migration And Freezing

Seasonal frozen and permafrost region distribution broad in our country,the construction of concrete lining in these canals,often canal base canal frost heave in frozen soil frost heave and lining damage problem,lining canals of frost heaving damage can lead to leakage of water,waste water,not only reduces the effective utilization of water,and reduced the service life of the canal,restricting the engineering benefit.Therefore,research mechanism of frozen soil frost heave,and from place to place is appropriate,put forward the effective measures of antifreeze,antifreeze expansion is the key to solve practical engineering problems.In this paper,based on the mechanics of frozen soil,frozen soil physics,mechanics of materials,such as theory,a coupling relationship and the permafrost thermal water canal concrete lining of frost heaving damage mechanism are summarized,and centered around the frost heaving damage of trapezoidal lining canals are studied from three aspects:(1)theoretical model is established.According to the theory of frozen soil physics and soil water dynamics related set up considering phase change and moisture migration in saturated frozen soil frost heave model;(2)the numerical simulation analysis.Using the finite element analysis software COMSOL to double membrane lining canal are numerically simulated,analysis of the temperature field,deformation field,stress field distribution;(3)the indoor experimental study.Routine soil tests in the laboratory and trapezoidal lining canals frost heave model experiment,the observation canal base of permafrost under the thermal dynamic coupling of water temperature,displacement,water distribution and change rule.Specific content is as follows:(1)moisture migration in permafrost and phase change of significant effects of latent heat on temperature field,as a result,this paper established the moisture migration and saturated frozen soil frost heave model of phase change latent heat.Model will be frozen as a swelling materials at low temperature,phase change latent heat as the material of the heat conduction equation of equivalent heat capacity to join;According to the Clapeyron equation and darcy's law to establish a saturated frozen soil freezing front expression moisture migration and migration phase change latent heat of water as heat source heatconduction equations;Using COMSOL temperature and frost heave of soil column,and irrespective of the phase transformation and moisture migration model is concluded: the effect of phase change on soil column had a greater influence on the temperature field,after considering phase change,because of the great migration of water phase change effect release of latent heat of moving heat source,make the temperature field in advancing slowly;Through contrast and Konrad one-dimensional freezing experiment results,the rationality of the model was verified,and provide reference for further saturated frozen soil frost heave research.(2)combined with finite element analysis software COMSOL double film anti-seepage lining canal are put forward on the li xudong antifreeze expansion mechanism has carried on the further research and perfect,will consider in this paper,phase change and moisture migration in frozen soil frost heave model is applied to double membrane lining canals,and adopt related to the temperature of frozen soil nonlinear constitutive,simulation results show that: comparison considering and not considering the phase change of channel simulation results,considering phase change of water and migration on the effect of temperature,channel base frozen depth decreases and closer to the prototype channel actual deep freeze,validate the rationality of the frost heave model in this paper.In contrast to the common channel lining and double membrane lining canal with the displacement field and stress field.The results show that: lining canal with double film due to weakening of the frozen restraint,the release of the freezing force,lead to the lining plate method to displacement than the ordinary lining channel overall increased,but the distribution is more uniform and double membrane channels can effectively reduce the normal frost heaving force and tangential to freezing force and improve the lining stress state.(3)canals for concrete lining of frost heaving damage problem,the indoor model experiment,observed the canal distribution of temperature field,moisture field,and designed a ordinary lining canals and double membrane contrast experiment.Analysis of experimental data,we get cool began,with lower temperature,frost advance gradually,and the soil freezing canal base,near the canal slope top and canal part temperature gradient is bigger,small temperature gradient near the canal base;Due to the effect of moisture migration,a large number of migration will release huge latent heat of water is frozen,hinder the rapid advance of freezing,and reduces the cooling rate of the soil;Comparing the relative tangential displacement,can get double membrane canal slope plate relative displacement of the biggest proportion is 13.4%,and ordinary lining canal slope plate,the tangential displacement;Can be seen from the distribution of moisture field,with thepassage of freezing front,the canal base not frozen water content decreases,canal bottom water were constantly moving to the freezing front and no matter at the end of canal and drainage,as long as in any level height,not frozen water lateral migration supply in preference to the vertical migration.In this paper,the model experiment in order to further the hydraulic structures of frost heaving experiment research laid the foundation.