Finite Element Analysis And Caculation Of The Floor Cracks Of Trapezoidal Concrete Lining Channels

China is a country with vast territory and large population, but is seriously lacking inwater resources, in consider of this situation, we should take certain measures to make full useof limited water resources to solve the water shortage problem. Countries and areas all overthe world are taking active measures to protect water resources to achieve the plan ofconstruction of water-saving society and development of water-saving agriculture, but thechannel in the process of water delivery has caused severe loss of agricultural water and canalseepage control can effectively reduce the waste of water resources. At present, the concretelining channel is the most widely used form of anti-seepage, but concrete with poor versatility,in permafrost region while the canal base causes frost heaving force to canal lining floor afterthe frost, will make the damage of the canal lining floor, such as cracks, slump and lift-up,and other forms of damage, seriously even affect the normal use of the channel, thus need torepair or rebuild the lining channels and influence the exertion of economic benefit of waterconservancy projects. To solve the problem of channel anti-seepage is in urgent need. Thereason why Trapezoidal concrete lining channel occurs frost heaving damage is because ofhaving not grasped its regularity and not calculated the reasonable thickness of its liningboard crack, thus failing to take appropriate measures to prevent the damage of channel frostheave. In order to study the regularity of trapezoidal concrete lining channel and get thereasonable thickness of base floor design, this paper carried out the following works:(1) Through consulting a large number of relevant materials, we get the trapezoidalconcrete lining channel mechanism of frost heave, frost heave damage causes andcharacteristics of frost heave, laying the foundation to establish a trapezoidal concrete liningof frost heave mechanics model and finite element model, as well as to calculate the thicknessof floor crack.(2) Regard the lining board and canal base permafrost as a whole, as transverse isotropiclinear elastic material to establish finite element model, in the use of large-scale finite elementanalysis software ANSYS to do a thermal stress coupling analysis based on the finite element model of Gansu province Jinghui trapezoidal channel, calculated the trapezoidal concretelining channel temperature field, stress field and displacement field of distribution thatprovide scientific basis for the design and construction of trapezoidal concrete lining channel.The temperature gradient of shady slope is greater than the temperature gradient of sunnyslope in the temperature field, stress of shady slope is greater than stress of the sunny slope inthe stress field, the stress in the top of the hill and near the toe department is relatively large ofthe slope board, the stress in the middle of bottom plate and near the shady parts is relativelylarge, the displacement of shady slope in the whole is greater than that of the sunny slope inthe displacement field, the displacement of the crest slope and the toe plates is larger of slope,the displacement in the middle and near shady slope is relatively larger of the canal bottomplate, which is in good agreement with the observed values and analyzes the rule oftrapezoidal channel frost heaving damage.(3) The channel floor exists initial crack, we establish intensity factor fracture criterionand regard â… complex fracture toughness as a strength index of judging when fracture, thenapply fracture mechanics knowledge to calculate trapezoidal channel concrete lining crack inorder to achieve more reasonable design thickness of the lining of the floor, then using finiteelement analysis software to analyze the channel bottom plate with crack, get the stressintensity factor of the crack tip of bottom plate, then simulate the crack propagation process ofchannel bottom plate by finite element, which compares match with the actual destructionwithâ…  crack, therefore, it can be applied to analysis cracks produced by channel frostheaving and provide a reasonable basis and reference for concrete bottom plate of liningtrapezoidal channel design and monitoring of cracks in the future.