Study On The Base Damage Mechanics Of Bridge And Building Under Ground Fissure With Large-scale Tests

Since the1980s, the reform and opening up policy was making the national economy developed rapidly. However, with the development of economy is human activity intensifies, which has caused the occurrence of various geological hazards. Ground fissures, as a special kind of urban geologic hazard, wide distribution in Fenwei basin, the place of buildings none escape by luck to destruction. Due to the inevitable and long-term cumulative of the ground fissures activity, it lead to the building’s destruction has caused high attention of the academic and engineering scholars. Taking Fenwei basin as research background, with the national natural science foundation in key projects (40534021) Fenwei basin formation mechanism and ground fissures continental dynamics、national natural science foundation surface projects (40772183) ground fissures activities under the environment of strata--metro tunnel interaction and land resources survey projects (1212010641403) Fenwei district ground fissures subsidence comprehensive study to rely on. Adopting combining methods of field survey、large physical simulation experiment and numerical analysis. Analyze failure mode and process of various buildings which caused by the ground fissures and propose the warning methods and control measures in this foundation. The mainly research work and results are as follows:(1) Through field investigation method, and summarize the destruction characteristics of various buildings under the environment of the ground fissures activities. Including roads、 bridges、underground pipes and houses, and base on the historical activity characteristic of ground fissures, point out that the ground fissures of Fenwei basin are still at active period in the future.(2) Through large physical model test, it reveals that the different structure forms of bridge and ground fissures in different locations intersect anywhere the crack activities of stress-strain regularity of deformation and failure mechanism, which provide the reference of building bridges scientific in fissures areas.(3) Through numerical simulation, it reveals that the normal faults, thrust faults and fault translation faults different forms of ground fissures formed to bridge the stress variation rules and failure modes, which points out the reasons of the formation of crack is different from the bridge has different effect, thus caused different failure modes. Therefore, when the design should first make clear the type of ground fissures, such ability to take a more reasonable measures of prevention.(4) Through large physical simulation experiment and numerical analysis, this paper discusses the various building foundation forms in the ground fissures activities under the environment of response, which points out the pile raft foundation of pile soil played the reinforcement although role, but still be upward plate tilt, this experiment occurred to resist ground fissures activities role is not significant; through the tube raft foundation of stress-strain curve analysis obtained tube raft foundation in ground fissures in the environmental impact of stress pattern; based on the same basis and ground fissures in different locations that ground fissures intersection intersect place for basic failure process influence; according to the different foundation forms contrast that ground fissures influenced range should adopt integrity good foundation forms, avoid to take the integrity of poor foundation base, etc.(5) Through to the basic model failure process and destroy the phenomenon, the paper suggests that although the different basic showed different plastic deformation ability, but eventually none escape by luck all destroyed, further verified ground fissures of buildings damage inevitable sex.(6) Through the same base form different stiffness and strength of illuminates, relying exclusively on increase based the intensity and rigidity to resist ground fissures in the building’s demolition without economic, the effect is not obvious.(7) In the investigation, based on the analysis of the houses, roads, Bridges, underground pipelines, etc. physics experiment and numerical pointed out various kinds of structures and buildings objects in the ground fissures activity environment destruction of mechanics model.(8) Based on building the failure mode of the cracks in the ground fissures, it puts forward the environmental impact of two kinds of warning methods. Therefore, according to the early warning signals we can do processing measures.(9) Through the ground fissures activities under the environment of various buildings failure mode, it puts forward the research building resistance ground fissures from two aspects:namely starts from the structure and measures of foundation for processing. It provides a good reference and guidance of constructing building in fissures areas.