Monitoring To Structural Durability And Damage Identification Of Tunnel Lining Under High Water Pressure

With the influences of interior and outer actions and factitious and natural factors, In-service structures will be deteriorated, damaged and failed as time going. These irreversible processes decreased the service performance and even safety of the structures. Damage to structure was concerned for a long time, it's defined as the deviation and decreasing of the structures performance, and includes service performance deterioration and local damage generation in life time of the structures. Slow materiality damage and stresses-induced damage of concrete both bring deterioration to structure. It's difficult to get precise damage identification and localization of the slow damage of concrete, so the preferable method to detecting structure performance is integral behavior recognition through Structure Health Monitoring (SHM).Damage Mechanics (DM), damage identification method, and SHM method are used to a tunnel lining structure under high water pressur to get long-time damage evolution, real-time behavior, structural safety of the lining.The research work and achievement mainly include:(1) Based on the study of the characteristics of tunnel lining under water pressure, the main durability deteriorate factors to the lining concrete are determined and evaluated, those are skin-deep carbonization and cracks caused by hydraulic fracture of the concrete, corrosion of the reinforcement.(2) The permeability characteristics of concrete are analyzed for getting the relation between the permeability coefficient and the Crack Opening Displacement (COD), and relation between local stresses states and COD.(3) The definition and classification of damage of concrete are presented in this dissertation; it's defined as inevitable performance decreasing of the concrete in service caused by deteriorate factors. Damage of concrete includes two major classifications: materiality damage and stresses-induced damage. To former, damage band and its expression are proposed. The constitutive model of latter is proposed, which composed of criterion damage, damage evolution and damage expression.(4) Through the preview of the damage identification methods, an integral damage stresses detection method with measured data is proposed for tunnel lining concrete structure. It's an efficient, simple, direct and easy-handle method for structural damage identification, but the localization of the damage is difficult.(5) Finally, combined with practical engineering, a SHM system to tunnel lining is introduced in this dissertation.