The project belongs to the field of water conservancy engineering and coastal engineering.
Relying on the preparation of a new round of seawall planning in Shanghai, the project "Research and Application of Risk Assessment and Defense Standards for Seawall Planning" was carried out, which includes: Application of risk management theory in seawall management, identification and analysis of influencing factors on seawall risk management, identification and analysis of influencing factors on seawall safety and defense standards, statistical analysis of wind, tide, waves, etc. at the front of seawall, possibly the most unfavorable storm surge and seawall defense capacity assessment, seawall economic optimal fortification standards, seawall strategies to deal with storm surge risks, seawall engineering measures and non-engineering measures to deal with storm surges, seawall overall layout and construction timing, etc. The research achieved the following main results:
(1) Comprehensively using natural disaster risk management and engineering project risk management theories, the research reveals the risk management characteristics of seawall projects, and uses various methods such as fault tree analysis, damage path and hierarchical analysis to systematically identify seawall safety and defense standards. The main influencing factors.
(2) Carry out frequency statistical analysis and rationality demonstration on the tide level, wind speed, waves, etc. that affect the defense capabilities of Shanghai's seawall. For the first time, based on obtaining statistical results of wind speed and frequency of a long series of coastal typhoons, use hydrological statistical analysis principles to reveal the original sea wall fortification standards are basically equivalent to the wind and tide frequency standards.
(3) Based on the mathematical model of storm surges and historical storm surge statistical data, the most unfavorable path and intensity of typhoon storm surges that may be encountered in the Shanghai sea area and their impact on seawall safety were simulated, and the ability of seawall to prevent risks was evaluated.
(4) For the first time, the combination transcendence probability method of dual disaster factors is proposed, the relationship between the combination transcendence probability and the combination return period of dual disaster factors is deduced, the combination return period relationship of wind, wave and tide double disaster factors is discussed and established, and the seawall is studied from the theoretical and practical perspectives. Optimal economic defense standard.
(5) Based on risk assessment, the seawall of Shanghai City was divided, and the sub-regional defense standards and the overall layout of the seawall of "one arc and three rings" were determined, and their relationship with relevant plans was analyzed and evaluated.
(6) Based on the current weak links and structural characteristics of the seawall in Shanghai, specific engineering and non-engineering measures to strengthen the safety of the seawall are proposed, such as heightening and reinforcing the main seawall, silting promotion and beach protection projects, and regulation of green ridges.
The main innovations of the research are as follows:
(1) The risk management characteristics of seawall projects are revealed, and the main influencing factors on seawall safety and defense standards are systematically identified.
(2) The typhoon storm surge with the most unfavorable typhoon path and intensity that may be encountered in the Shanghai sea area and its impact on seawall safety were simulated, and the ability of seawall to prevent risks was evaluated.
(3) Based on risk assessment, Shanghai City's seawall fortification was divided and sub-regional defense standards were established.
(4) For the first time, the transcendence probability method of dual disaster factor combinations is proposed, and the return period relationship of wind, wave and tide dual disaster factor combinations is established.
The results have been applied to the "Shanghai City Seawall Planning (2011-2020)" approved by the Shanghai City Government ("Hufu [2013] No. 88" Document), the Shanghai City Engineering Construction Code "Design Code for Sedimentation Promotion and Enclosures for Land Reclamation Projects (DG/TJ08 -2111-2012, J12144-2012)", and the Nanhui East Beach Siltion-Promotion and Enclosures and other engineering practices.
The research obtained 1 authorized invention patent (ZL201110314836.5) and published 4 papers (2 published in SCI and 1 published in CPCI-S).
The research results have been successfully applied in Shanghai City seawall planning, compliance reinforcement projects and relevant technical standards, improving the ability of Shanghai City seawall to prevent storm surge disasters, ensuring Shanghai's urban safety, and achieving significant economic and social benefits. The seawall defense standard determination method based on risk management theory and the seawall emergency strategy for dealing with storm surges adopted in the study can be applied to many related fields such as flood control engineering, coastal engineering, and ocean engineering, making up for the research gaps in this regard at home and abroad.
The research sub-items "Shanghai City Seawall Defense Capability Evaluation Research" and "Shanghai City Seawall Planning Research Report" both won the first prize in Shanghai City Excellent Engineering Consulting (December 2013, December 2015).