【作者】 刘聪；

【导师】 江志红；

【作者基本信息】 南京信息工程大学 ， 大气科学， 2008， 博士

【摘要】 针对现代大桥发展实际及国内桥梁设计风参数确定及施工气象安全保障的需求,在分析国内外相关现状及存在问题的基础上,开展桥梁设计风参数计算方法和施工气象安全保障技术的研究,并依托苏通大桥和青岛海湾大桥建设项目,进行工程化试验。主要成果和结论:基于统计学、天气气候学和流体力学物理量分布连续性原理,构建了适合我国实际的设计风速计算方案,并通过工程化试验,为依托工程提供设计风速地同时,解决了桥位风速资料缺乏无法计算重现期风速及直接采用规范值不能反映桥位特征的问题。结合气象统计学原理及桥梁建设实际,引入广义极值分布模型,给出一定保证率下实际风速不会超越的极值风速算法,将工程□外包线”的主观确定客观化,解决了现行规范使用单一极值分布模型造成的可能不适应及验证风速分布归属某一分布的困难,降低了风参数确定主观化和拘泥于现行规范带来的工程风险。开展了较长时间的水面、水岸与气象站同步观测试验和风攻角等湍流特性的观测研究,揭示出一些不同于以往风工程理论的观测事实,这些工作对桥梁抗风设计风参数的确定起到积极作用,也为相关标准、规范制修订提供了基础数据。运用WRF中尺度模式进行了宽阔水面大风的数值模拟和敏感性试验,评估了模式对水面极值风速的模拟能力及模式参数化方案对模拟效果影响的敏感性。开发GPRS与Internet相结合的远程数据传输技术,建立江面大风等预报模式,编制集信息采集、传输、应用于一体的系统软件,构建了工程区气象安全保障系统,并通过工程化试验,证明了其可行性和有效性。通过理论研究、实地观测试验、数值模拟和研究成果工程化试验,证明了:①直接采用气象站资料或规范的计算结果表征桥位风参数会造成较大的误差;②研究提出的设计风参数计算方法能够一定程度上克服现行方法的不足;③特殊地理条件下,桥位风攻角、湍流功率谱等湍流特性值及水面与水岸、气象站风速差异与规范推荐值存在不同程度差异,实地观测试验有助于修正标准、规范值;④水陆分布是造成桥位与气象站风速差异的主因,WRF模式对桥位风速具有一定模拟能力,但目前尚不具备工程化的能力;⑤建构桥位气象安全保障系统可有效提高工程区预报正确率,满足施工对气象安全信息的需要。更多还原

【Abstract】 For the purpose of development of modern large bridges and the demand for establishing bridge design wind parameters and the requirements for meteorological safety controlling in bridge construction, methods to calculate wind parameters in bridge designing and techniques to ensure meteorological safety were studied and were tested in the projects of Sutong Highway Bridge and Qingdao-bay Bridge, based on analysis of the current development and problems worldwide. The main conclusions drawn from this study are as follows:Suitable approaches to calculate wind speed in bridge designing were developed and tested in bridge constructions based on statistics, synoptic meteorology and climatology, and the principle of continuity of mass distribution in hydrodynamics. While providing the bridge designers with wind parameters, this study also solved the problems that wind velocities can not be calculated at bridge locations because of lack of wind velocity data, and that the values obtained from handbooks cannot reflect the characteristics at bridge locations.Considering both the theories of meteorological statistics and the realities in bridge construction, a generalized model of the distribution of extreme values was introduced. The model provides a method to calculate extreme wind speeds under the condition that the real wind velocity will not be exceeded. The subjective determination of the (?)nvelope line? in construction was objectivized. The problems about the probable maladjustment resulted from present criterions using single-extreme distribution model and difficulties to verify the attribution of the distributions of wind speed to a certain distribution function were solved. The engineering risk resulted from subjective determination and sticking on present handbook of wind parameters was reduced.A long time synchronous meteorological observations over water surface, at the riverbank and at the weather stations were conducted, as well as the observations of turbulence characteristics such as wind attack angles. These observations reveal some new observational evidence that are different from the previous theories. These works have a positive effect on determination of wind parameters in bridge designing, and also provide the basic data for correcting the standards and rules.The meso-scale model WRF was used to simulate wind field over broad plain water surface and to test the model(?)ability to reproduce the extreme values of wind speed and the sensitivity of simulation results to parameterizations of various physical processes.A long-distance data transmission technique which combines GPRS and Internet is developed; models for predicting wind over river surface is established; software which combines information collection, transmission and application is developed; a meteorological safety protection system for construction zones is established. All these are proved feasible and effective by operating engineering experiments.Through theoretical studies, observational experiments, numerical simulations and engineering experiments the following conclusions are drawn:(1) Large bias may be resulted if the meteorological data obtained from weather stations or calculated from handbooks are used directly to represent wind parameters at bridge locations.(2) The methods for calculating wind parameters proposed in this study are able to overcome some of the drawbacks existed in the popular methods.(3) Differences may exist between turbulence identities such as wind attack angles and turbulence power spectrum at bridge location and criteria. The differences between wind velocity over water surface and that at riverbank or weather stations are also discriminate from the criterion values. Therefore, the observation experiments are useful to improve the criterion values.(4) The distributing of water and land is the main reason which leads to the differences between the wind velocity over water surface and that at weather stations. The WRF model has a certain degree of ability to simulate the wind velocity at bridge location, but can not be directly used for engineering projects yet.(5) Establishing the system ensuring meteorological security in construction regions can improve the veracity of weather predicting in construction regions and meet the needs of meteorological security information during constructions.更多还原