应用蒙特卡罗免疫遗传算法分析土坡的稳定可靠 性   总被引：1，自引：0，他引：1  

冯利军  李竞生 《工程地质学报》2008,16(1):76-83

本文借鉴疫苗提取、疫苗接种、免疫记忆、基因亲和突变、基因重组等思想提出了一种改进的免疫遗传算法。在此基础上研究了基于本文免疫遗传算法的土坡最危险滑动面搜索方法,并将该方法与蒙特卡罗随机模拟技术相结合,用于土坡稳定可靠性分析。工程实例计算结果与实际情况相符,验证了算法的有效性和分析方法的正确性。  相似文献   

高边坡结构可靠度的二次处理有限元分析   总被引：1，自引：1，他引：0  

宋云连  汲敏  李树军 《工程地质学报》2008,16(4):522-527

本文依据强度折减理论,利用MIDAS/GTS有限元软件,分析计算了高边坡结构的安全系数K,找到边坡滑裂带的位置。在此基础上,对有限元输入数据和输出结果进行二次处理,建立基本随机变量c,f与滑裂带中单元的最大(和最小)主应力1(和3)的拟合关系f1(和f3),将其代入高边坡结构的功能函数Z中,使Z由隐式形式变为显式。基于该显式表示的Z,利用Monte Carlo法计算滑裂带中所有失效单元的可靠指标1,并将其单元面积A1作为权重系数,经过加权平均得到边坡结构的整体可靠指标。上述方法使得结合有限元软件计算边坡结构的整体可靠度得以简化。经实例分析可知,本文提出的方法是合理可行的,可使边坡结构整体可靠性分析得以简化,也可为高边坡结构整体可靠性分析提供理论参考。  相似文献   

Probabilistic mapping of flood-induced backscatter changes in SAR time series     

《International Journal of Applied Earth Observation and Geoinformation》2017

The information content of flood extent maps can be increased considerably by including information on the uncertainty of the flood area delineation. This additional information can be of benefit in flood forecasting and monitoring. Furthermore, flood probability maps can be converted to binary maps showing flooded and non-flooded areas by applying a threshold probability value p_F = 0.5. In this study, a probabilistic change detection approach for flood mapping based on synthetic aperture radar (SAR) time series is proposed. For this purpose, conditional probability density functions (PDFs) for land and open water surfaces were estimated from ENVISAT ASAR Wide Swath (WS) time series containing >600 images using a reference mask of permanent water bodies. A pixel-wise harmonic model was used to account for seasonality in backscatter from land areas caused by soil moisture and vegetation dynamics. The approach was evaluated for a large-scale flood event along the River Severn, United Kingdom. The retrieved flood probability maps were compared to a reference flood mask derived from high-resolution aerial imagery by means of reliability diagrams. The obtained performance measures indicate both high reliability and confidence although there was a slight under-estimation of the flood extent, which may in part be attributed to topographically induced radar shadows along the edges of the floodplain. Furthermore, the results highlight the importance of local incidence angle for the separability between flooded and non-flooded areas as specular reflection properties of open water surfaces increase with a more oblique viewing geometry.  相似文献   

Uncertainty reduction and sampling efficiency in slope designs using 3D conditional random fields     

《Computers and Geotechnics》2016

A method of combining 3D Kriging for geotechnical sampling schemes with an existing random field generator is presented and validated. Conditional random fields of soil heterogeneity are then linked with finite elements, within a Monte Carlo framework, to investigate optimum sampling locations and the cost-effective design of a slope. The results clearly demonstrate the potential of 3D conditional simulation in directing exploration programmes and designing cost-saving structures; that is, by reducing uncertainty and improving the confidence in a project’s success. Moreover, for the problems analysed, an optimal sampling distance of half the horizontal scale of fluctuation was identified.  相似文献   

Reliability assessment and integrity management of data buoy instruments used for monitoring the Indian Seas     

《Applied Ocean Research》2016

Reliable performance is the key requirement for instruments used in offshore moored buoys for cyclone monitoring, as under performance of the sensors can have a serious impact on the societal protection, and in addition, lead to costly repair and reinstallations. The instrument selection and application practices are based on the experiences of the global scientific community, and their performances are monitored based on IEC61508 standards. Reliability modeling based on experiences in the operation and maintenance of moored surface buoys for approximately two decades has identified that the sensor suite used for cyclone monitoring has a Mean Time Between Failure of 0.6 years, which is the basis of the implemented reliability centered maintenance strategies. As this is the first attempt to study the performance of such moored buoy instruments which have cumulatively clocked more than 7.3 million demanding offshore instrument-hours, the data presented shall serve as input for the offshore environmental instrument system design.  相似文献   

珠江三角洲生命线工程网络的震害分析     

黄昭庆  蔡新群 《华南地震》1995,15(3):52-60

对珠江三角洲地区生命线网络工程,在遭受本课题给定的４个震源地震袭击时所受到的震害进行了系统分析,预测其直接经济损失,并对网络工程的可靠性作了评估,此项成果可为制定防震对策提供基础依据。  相似文献   

提高无定向导线精度与可靠性的方法   总被引：1，自引：1，他引：0  

裴亮  李秀坤 《测绘工程》1998,7(4):59-63

提出在无定向导线上加测方向与边长的方法提高其精度与可靠性;按间接平差设计出无定向导线的计算程序,该程序除给出平差结果和精度评定数据外,还给出各种观测值的多余观测分量,进而以数据探测法进行粗差定位。用计算实例说明本程序的应用。  相似文献   

克拉玛依市多层砖混住宅阳台的结构可靠度计算     

唐丽华  尹力峰  崔平  王宏  李江田 《内陆地震》2004,18(3):242-247

介绍了克拉玛依市多层砖混结构住宅两种阳台的结构特点与计算模型，在此基础上对阳台的可靠度进行验算，认为虽然阳台的强度储备尚在安全范围之内，但应按照“概念设计”的思想对阳台进行可靠性分析及确定维修加固方案。  相似文献   

A reliability based approach for evaluating the slope stability of embankment dams   总被引：7，自引：0，他引：7  

R. Y. Liang  O. K. Nusier  A. H. Malkawi 《Engineering Geology》1999,54(3-4):271-285

Embankment dams are important and costly civil engineering structures that provide an essential infrastructure for the management of water. One of the critical aspects of dam design is the analysis of stability and safety of the earth structure under various operating and environmental conditions. Traditionally, a deterministic approach is used for such analysis. However, the determination of variables such as soil strength parameters, pore pressure and other pertinent properties involves uncertainties, which cannot be handled in the traditional deterministic methods. It is, therefore, highly desirable to develop a reliability based analytical/numerical methodology for stability analysis of dams taking into account these uncertainties. Reliability and probability theories are developed in this paper for assessing the reliability index and the corresponding probability of failure of multi-layered embankment dams and slopes. Two definitions were used to calculate the reliability index (i.e. the normal distribution and the log–normal distribution). The computer program was developed and validated by the Congress Street open cut failure case. The developed approach was used to study the stability of the King Talal embankment dam. The results are discussed and conclusions drawn.  相似文献   

泸州市电业局石马山边坡可靠度分析     

王俊  赵其华 《四川地震》2009,(1)

边坡稳定性的分析是边坡工程中最关键的,如何准确评价其稳定性是岩土工程界的热点问题。本文将Monte Carlo法应用于边坡稳定性的分析评价中,借助传统的极限平衡理论,建立边坡稳定的极限状态功能函数,并采用MATLAB语言编制Monte Carlo法计算边坡可靠度的计算机程序,从而获得边坡的失效概率与可靠度指标。相比传统的极限平衡理论,基于可靠度的分析方法能够更直观的反应边坡稳定性的现状,从而为工程人员提供更为可靠有效的帮助。  相似文献