Study On Several Key Issues Of Safe Operation Of Water Diversion Project

With the rapid development of China's social economy and the continuous improvement of water demand,water diversion project has become an important part of infrastructure construction,and provides important water security for urban life,industrial production,agricultural irrigation and ecological environmental protection.The safe operation of water diversion project is an important precondition to ensure the social,economic and environmental benefits of the project.However,due to the long engineering line,the complex and changeable engineering geology and environmental conditions,the aging of long-term operation and other factors,the water diversion project accidents often occur,causing huge economic losses and far-reaching social impact.Therefore,in the practical operation management and scientific research work,many key problems on how to ensure the safe operation of water diversion project need to be studied and solved urgently.In recent years,many scholars have done a lot of research on the safe operation of water diversion projects and made good progress.However,the relevant research has not yet formed a complete theory and technology,the existing achievements can not meet the actual needs of engineering management.Focusing on the theme of safe operation of water diversion project,this paper selects some typical structures of water diversion buildings from three perspectives of monitoring,evaluation and detection,and carries out detailed research on several key issues in combination with the actual situation of the project.It aims to make a little effort to promote the research process of the safe operation of water diversion projects.The main research content and conclusions are as follows:(1)Channel security monitoring based on statistical regression model.Referring to the relevant theories and methods of dam deformation safety monitoring,and taking the safety monitoring of channel slope deformation as an example,a unified technical path was proposed to establish the monitoring indexes and thresholding for the safety operation of different water diversion buildings,and the "three-level warning and one-level alarm" statistical prediction monitoring model was established for the deformation safety of channel slope.It is clear that the basis of safety monitoring is the identification of failure mode and path and the analysis of existing monitoring quantity,the key is the formulation of safety monitoring index and the analysis of typical building behavior and vulnerability,the core is the classification of safety monitoring index,and the result is the determination of monitoring threshold.(2)Channel security assessment based on in-situ monitoring and numerical analysis.Taking the safety of the channel slope as an example,combining with the results of measured data,the seepage condition inversion analysis and the finite element calculation,the safety stability was evaluated of the channel slope.The main conclusions are as follows:the underground water level of the channel slope is low,there may be local aquifers in the slope which will not affect the stability of lining,the channel water has weak extravasation,and the seepage condition of the slope is stable;The deformation of channel slope is very small,and mainly occurs in the shallow surface layer,without the signs of deep sliding.The anti-sliding stability safety factor meets the design requirements,the slope deformation is stable and there is still a large safety reserve;The anti-slide pile can effectively limit the shallow displacement of the slope,and the structure of anti-slide pile and slope beam can well resist the deformation of the slope and have a good supporting effect on the overwater section.(3)Pile foundation detection based on eddy current simulation technology.Taking PHC pipe pile as an example and based on the basic principle of far-field eddy current detection technology,a 3D finite element model of electromagnetic field was established for simulation analysis,and different coil arrangement positions and steel bar fracture conditions were compared.The main conclusion is that the Br phase is suitable for the detection index outside the tube.Br amplitude and Bz amplitude can be used to distinguish whether there is longitudinal bar fracture inside the tube.The steel structure of pipe pile is sparse,and the magnetic field disturbance range is small when the fracture occurs.Only when the excitation coil and the detection coil are close to the fracture position,the obvious magnetic field signal can be detected.