Studies On Numerical Simulation And Lining Structure Optimization For Frost Heave Damage Of U-shaped Lining Canal Considering The Mechanical Behaviors With Contact

According to a large number of investigation data in northern china, the canal system structures and canal lining is the most which effected by the foundation soil frost heave.Among them,the canal lining is sensitive to the effection of frost heave due to its small thickness and light weight.The freezing damage generally occur at the bottom of the canal and the bottom of slope position.The main damage form for lining deformation, cracks, uplift, and stripping down.Reflecting on the project, reducing the efficiency of routing,shortening useful life of canal buildings,deteriorate operating conditions,and increasing many unproductive labour, materials and investment to operation and maintenance, and even to rebuild.Mastering canal base soil frost heave mechanism and the destruction mechanism of canal lining structure and taking the necessary heaving damage prevention measures, have important practical significance to saving water and improve the agricultural production.In this paper,on the basis of reading books and reference which is related,I understand canal base soil frost heave mechanism and ABAQUS finite element theory and its applicability in the canal analysis of frost heave.And summary the study of frost heave model and canal antifreeze bilge numerical simulation theory at home and abroad.This paper mainly targets discussion and summary of finding the problem in the study of canal antifreeze bilge numerical simulation.As to the plastic failure of the concrete lining slab, concrete damage constitutive model is used with material nonlinear properties.As to the mechanical behavior between the concrete lining slab and canal soil,separation, adhesive and glide,normal contact model and the tangential contact model which ABAQUS comes with are used with the role of frozen soil freezing strength.And the model was applied to Baojixia irrigation area,comparing canals of simulated results and measured results, its rationality was verified.Then,based on Baojixia irrigation area,established different angle and different thickness of D600 type concrete lining canal with numerical simulation analysis,gave the region’s u-shaped canal reasonable lining angle range.In this paper, main content and achievements are as follows:(1) The coupled thermo-mechanical model was established,consdering Concrete and frozen earth nonlinear permafrost and the mechanical behavior between the concrete lining slab and canal soil,separation, adhesive and glide. With the increase of canal structure designrequirements, the elastic-plastic property of structure needs to be tested,only to get actual deformation of canal system structer under the circumantance of cycle of freezing and thawing. This paper used Concrete Damaged Plastic and Drucker-Prage plastic yield criterion which ABAQUS comes with to imitate inelastic mechanics behavior between the concrete lining slab and canal soil.The normal behavior between the concrete lining slab and canal soil,think contact surface can absorb a certain amount of tension which is equal to the corresponding negative temperature of frozen soil under freezing strength, frozen soil and concrete lining board open when the force exceed freezing strength.Friction model by means of the criterion of the Column and the allowed maximum shear stress intensity control, when the tangential stress exceeds allowed shear stress, think sliding canal base frozen soil and concrete lining board.Results shows that the model can reflect the mechanical behavior between the concrete lining slab and canal soil and the weak section of concrete lining board and degree of failure of frozen soil,in accordance with engineering practice.And regardless of the contact between the concrete lining slab and canal soil.And the maximum plastic strain of concrete with consdering the contact between the concrete lining slab and canal soil is 3.76 times than regardless of the contact. Considering the contact between the concrete lining slab and canal soil,normal frost heave force, tangential freezing force reduce 1.5-3 times.(2) U-shaped concrete lining structure is the main canal cross section form, thus,adopting the reasonable canal cross section is important link in the design of canal parameters.In this paper based on a frost heave model is put forward, on the basis of engineering cost minimum, give attention to the angle and the thickness of the lining.based on Baojixia irrigation area,established different angle and different thickness of D600 type concrete lining canal with different angles and the thickness,consdering distinguish between Yin slope and Yang slope,amount to 66 models.The results show that the minimum canal method to the frost heave amount as the target, reduce the possibility of damage concrete lining canal, both the stress uniformity and efficiency.For concrete lining canal slope does not distinguish between shady and sunny, the lining thickness of 8 cm and obliquity range of 18。~22。can be choosed.For concrete lining canal slope distinguish between sunny and shady,the lining thickness of 10 cm and obliquity range of 18。~20。can be choosed.