Frost Heaving Simulation Model Of Lining Canals Based On Heat-Moisture-Stress Coupled Fields Of Frozen Soils

In northern dry cold irrigation areas, the lining canals are damaged by frost heavingseriously which leads to nearly50%loss of conveyance, increases the cost for maintenanceand further influences the operation of canals. The damage has become a long-term, criticalproblem in water conservancy construction projects. The damage of lining canals duing toheat-moisture-stress coupled fields is the result of the interaction between frozen soils andlining structure in the process of freezing of the foundation soil. Previous canal frost heavingresearch based on heat-moisture-stress coupled fields of frozen soils, didn’t consider theinteraction between lining structure and frozen soil, simplify treated the concrete lining asload imposed on the canal foundation soil; some research which considered the interactionbetween lining structure and frozen soil didn’t consider heat-moisture-stress coupled fields offrozen soils, which couldn’t get the frost heaving forces and freezing force on lining structureand reflect constraint force of the lining structure and the influence caused by couplingprocess of soil freezing. Most existing heat-moisture-stress coupled model with self-compiledprogram implementation, rarely put forward using popular commercial finite elementsoftware, which make canal frost heaving research based on heat-moisture-stress coupledmodel difficult to promotion and application. Therefore, it is necessary to establish a platformfor general finite element based on heat-moisture-stress coupled canal concrete lining frostheave damage model, which provides a scientific foundation for lining canals frost heaving innorthern dry cold irrigation areas. In northern dry cold irrigation areas, the lining canals aredamaged by frost heaving seriously which leads to nearly50%loss of conveyance, increasesthe cost for maintenance and further influences the operation of canals. The damage hasbecome a long-term, critical problem in water conservancy construction projects. The damageof lining canals during to heat-moisture-stress coupled fields is the result of the interactionbetween frozen soils and lining structure in the process of freezing of the foundation soil. On considering physics of frozen soils, mechanics of frozen soils and hydrodynamics offrozen soils, it is systematically discussed that the concrete lining channel heat-moisture-stressthree coupled fields theory. Combined with multi-physics finite element software, detailedstudy about heat-moisture-stress coupled fields of frozen soils is done and proposed canallining based on heat-moisture-stress coupled fields of frozen soils with considering theinteraction with the canal lining and frozen soils. The main contents of this paper are asfollow:(1) Based on the assumption of rigid ice and unfrozen water incompressible,heat-moisture-stress coupled fields of frozen soils is deduced based on Harlan heat-moisturecoupled fields.(2) By introducing three power Heaviside step function instead of section function tosolving the frozen soil water thermodynamic coupling model, effectively makes thethermodynamics and hydrodynamics parameters before and after the freeze front smooth andcontinuous. Improve the accuracy of solving, and ease the grid of high demand when solveproblems of phase transition. Through Clapeyron equation and Z function, derivate theunified expression of soil water potential, unfrozen and the freezing phase change drasticallyarea to realize heat-moisture-stress coupled in general finite element platform. According tothe phase change temperature field model, heat-moisture coupling model, heat-moisture-stresscoupling model, the numerical simulation by finite element method, and its calculation resultswith existing test comparing the measured results to verify.(3) By the heat-moisture-stress coupled model presented in the paper, numericalsimulation research of concrete lining of frost heaving in Jinghui, compared with the heat-stress coupling analysis which neglected the moisture migration, revealed the canal liningfrost heaving stress and deformation law under the influence of moisture migration, provide ascientific basis for accurate analysis of damage rule of canal lining frost heaving.(4) Due to the existing of only experimental study and empirical results aboutreplacing-soil for canal foundation soil which is a commonly used measure to avoid canallining frost heaving. A method consider the low surface energy of coarse grain soil andmoisture migration phenomenon is weak, heat-moisture-stress coupling model is used in theunreplaced soil, replaced soil use the heat–stress coupling model to analysis. Using finiteelement software to measure different in the depth of replace soil, simulation of themechanism of canal lining frost heaving, can provide scientific basis for channel usedantifreeze expansion measures.