Research On The Seismic Reliability Analysis Method Of Urban Water Supply Network And System Development

As an important component of lifeline engineering,the water supply network system is the vitals for maintaining social production,life,and normal city operation.After the earthquake,it undertakes the arduous task of ensuring medical water,fire water and domestic water of disaster victims.With the continuous progress of urban seismic resilience evaluation process,theories of seismic damage risk prediction and reliability evaluation of water supply network system have recently been researched widely,and also,a large number of research results have been obtained.However,there is no systematic theoretical method and software platform for seismic damage prediction and seismic reliability analysis of water supply network in our country.Therefore,the aseismic reliability analysis method of water supply network is researched from the element level and system level in this dissertation,and the aseismic reliability analysis plug-in system is developed as well.This study lays a theoretical and technical foundation for earthquake damage prediction and aseismic reliability analysis of water supply network system.The main contents and achievements are listed as follows:(1)Based on the theory of soil elastic strain threshold,the frequency-dependent equivalent linear method considering the reduction of strain interval was established.The seismic response of soil layers in various sites was analyzed by utilizing the proposed method,and then the difference between the proposed method and the traditional equivalent linear method was compared.The study solved the lower frequency response magnification analyzed by traditional method in high frequency band.A soil layer seismic response analysis system integrated with this proposed method is developed to realize the efficient and accurate analysis of site seismic response.Then the site seismic response analysis in Xi'an area used existing system was carried out,and the site effect prediction model considering the input seismic peak acceleration,equivalent shear wave velocity and overburden thickness was established.Finally,the deterministic seismic risk analysis considering the site effect was carried out,and the analysis results were consistent with the actual earthquake damage states.(2)Considering pipe properties,site conditions,corrosion environment,degradation performance and buried depth,an extensible pipeline classification method was proposed.Based on the analytical seismic vulnerability analysis theory,the probabilistic seismic demand models and probabilistic seismic capacity models of typical ductile iron pipes were established,and the seismic vulnerability curves of pipelines with different buried depths were obtained.Combining seismic damage rate of pipelines,the seismic fragility curves of typical pipelines with different diameters and buried depths were established through theoretical derivation.The pipeline seismic vulnerability curve management system was developed by utilizing C#(C Sharp)programming language.It realized effectively input,storage,comparison and visualization of seismic fragility curves.Finally the pipeline unit seismic fragility curve database was established.(3)Based on the seismic fragility curve of pipeline element,the calculation method of pipeline three-state failure probability was proposed.In allusion to slow error convergence of Monte Carlo method used in seismic reliability evaluation of pipeline network,a quasi-Monte Carlo method sampled by Sobol low discrepancy sequence for reliability evaluation was proposed.Furthermore,combining GPU technology,a parallel algorithm of network reliability evaluation based on CUDA was proposed,and the efficiency and accuracy of reliability evaluation were significantly improved.(4)The hydraulic model of seismic damaged pipeline network was established,which considering the states of pipeline leakage,pipeline burst and low nodal pressures comprehensively.Based on quasi-Monte Carlo method,the hydraulic calculation method and seismic functional reliability evaluation method of seismic damaged pipeline network were proposed to simulate and evaluate the hydraulic state of seismic damaged pipeline network accurately.The hydraulic satisfaction index of water supply network and the hydraulic importance index of earthquake damaged pipeline were established,and the two-stage repair strategy of earthquake damaged pipeline were proposed.Then,a multiobjective optimal scheduling model of leakage pipeline repair team were established,and the genetic algorithm was utilized to search the optimal solution of the model.Finally,the optimal repair sequence of pipelines and the optimal scheduling scheme of repair teams were given.(5)Based on the idea of software layered architecture and plug-in development,a plug-in framework platform was built,and then a plug-in system for water supply network seismic reliability evaluation was developed by utilizing multi-language mixed programming technology.The key technology of system development,structure design,framework platform design were elaborated.Finally,the plug-in system was applied to the water supply network in the main urban area of Xi'an as a preliminary case study.The evaluation results provided theoretical guidance for the government and relevant departments to carry out the reinforcement optimization design of pipe network,seismic performance-based design,pipe network resilience evaluation and emergency plan formulation.