融合地形和土壤特征的流域蓄水容量模型     

向小华  宋琪峰  陈喜  吴晓玲  王船海 《水科学进展》2013,24(5):651-657

以van Genuchten模型表述的土壤水分特征曲线为基础,推导出流域单点缺水量,并结合TOPMODEL模型中地形指数与地下水位关系,建立了反映地形和土壤特征共同影响的蓄水容量模型,通过统计方法从栅格尺度蓄水容量获得流域尺度蓄水容量曲线,取代传统新安江模型中率定的蓄水容量曲线。以淮河流域紫罗山子流域为例,分析地形特征与土壤类型对蓄水容量的影响;并与实测流量过程以及原新安江模型模拟的流量过程对比,表明模型能较好地模拟场次洪水过程。模型将蓄水容量曲线显式表述,减少了新安江模型参数,为无资料地区的水文模拟提供了分析方法。  相似文献   

3D Gravity Inversion by Growing Bodies and Shaping Layers at Mt. Vesuvius (Southern Italy)     

Giovanna Berrino  Antonio G. Camacho 《Pure and Applied Geophysics》2008,165(6):1095-1115

To improve our knowledge of the structural pattern of Mt. Vesuvius and its magmatic system, which represents one of the three volcanoes located in the Neapolitan area (together with Campi Flegrei and Ischia; southern Italy), we analyze here the Bouguer gravity map that is already available through its interpretation by means of 2.5-dimensional modelling. We have carried out a three-dimensional interpretation using a new and original algorithm, known as ‘Layers’, that has been especially processed for this purpose. Layers works in an automatic and non-subjective way, and allows the definition of the structural settings in terms of several layers, each representing a specific geological formation. The same data are also interpreted in terms of isolated and shallow anomalous density bodies using a well tested algorithm known as ‘Growth’. We focus our inversions on the Mt. Vesuvius volcano, while globally analyzing the entire Neapolitan area, in order to investigate the deep structures, and in particular the deep extended ‘sill’ that has been revealed by seismic tomography. The final models generally confirm the global setting of the area as outlined by previous investigations, mainly for the shape and depth of the carbonate basement below Mt. Vesuvius. The presence of lateral density contrasts inside the volcano edifice is also shown, which was only hypothesized in the 2.5-dimensional inversion. Moreover, the models allow us to note a high density body that rises from the top of the carbonate basement and further elongates above sea level. This probably represents an uprising of the same basement, which is just below the volcano and which coincides with the V_P and V_P/V_S anomalies detected under the crater. The three-dimensional results also reveal that the two inversion methods provide very similar models, where the high density isolated body in the Growth model can be associated with the rising high density anomaly in the Layers model. Taking into account the density of these modelled bodies, we would also suggest that they represent solidified magma bodies, as suggested by other studies. Finally, we did not clearly detect any deep anomalous body that can be associated with the sill that was suggested by seismic tomography.  相似文献   

A parallel evolutionary strategy based simulation–optimization approach for solving groundwater source identification problems     

Baha Y. Mirghani  Kumar G. Mahinthakumar  Michael E. Tryby  Ranji S. Ranjithan  Emily M. Zechman 《Advances in water resources》2009

Groundwater characterization involves the resolution of unknown system characteristics from observation data, and is often classified as an inverse problem. Inverse problems are difficult to solve due to natural ill-posedness and computational intractability. Here we adopt the use of a simulation–optimization approach that couples a numerical pollutant-transport simulation model with evolutionary search algorithms for solution of the inverse problem. In this approach, the numerical transport model is solved iteratively during the evolutionary search. This process can be computationally intensive since several hundreds to thousands of forward model evaluations are typically required for solution. Given the potential computational intractability of such a simulation–optimization approach, parallel computation is employed to ease and enable the solution of such problems. In this paper, several variations of a groundwater source identification problem is examined in terms of solution quality and computational performance. The computational experiments were performed on the TeraGrid cluster available at the National Center for Supercomputing Applications. The results demonstrate the performance of the parallel simulation–optimization approach in terms of solution quality and computational performance.  相似文献   

基于敏感性分析的裂隙岩体渗流与应力静态全耦合参数反演   总被引：5，自引：3，他引：2  

王媛  刘杰 《岩土力学》2009,30(2):311-317

基于求解稳定渗流场与弹性位移场耦合问题的全耦合分析方法,应用提出的混合遗传算法作为优化算法,同时利用水头、位移等多类型量测资料,提出了裂隙岩体渗流与应力静态全耦合的参数反演方法。在目标函数建立中考虑了实测水头对渗流参数的敏感性,在待反演力学未知参数的选取中,依据提出的相对灵敏度概念,考虑了实测位移对力学参数的敏感性。针对某裂隙岸坡算例,研究了水库蓄水过程中位移场对力学参数敏感性,据此实现位移测点的优化布置,并以渗流场与位移场全耦合正分析计算结果作为假想实测值,进行该岩坡的全耦合参数反演分析,从而验证了所提出理论与研制程序的正确性和可行性。  相似文献   

基于?－SVR和GA的初始地应力场位移反分析方法研究     

余志雄  周创兵  陈益峰  李俊平 《岩土力学》2007,28(1):151-156

基于一种改进的支持向量机（?－SVR）和改进的遗传算法（GA）,提出一种初始地应力场位移反分析方法。该方法通过正交设计方法安排较少次数的正分析方案,用?－SVR对正分析中测点位移值与参数构成的样本集进行学习,建立参数取值与观测点测值的非线性隐式方程;采用确定性或随机反分析的思路确定反分析的优化目标函数,并利用GA搜索最优参数取值。采用?－SVR方法建立的参数取值与位移量测点测值的非线性隐式方程,能够以很高的精度拟合和预测不同参数取值时的观测点测值,因此,可以用该隐式方程代替正分析,减少计算量;采用改进的GA方法能够准确搜索到最优参数;搜索到的最优参数值与理论值相当吻合。算例表明,基于?－SVR和GA的初始地应力场位移反分析方法是一种行之有效的初始地应力场位移反分析方法,可以广泛用于初始地应力场确定性反分析和随机反分析。  相似文献   

土钉支护结构优化设计的有限元分析     

高盟  高广运  张远芳 《岩土力学》2007,28(11):2461-2464

考虑土钉-土体的相互作用,建立三维有限元模型,分析计算土钉支护结构的内力和位移,提出了变形控制和应力控制相结合的优化设计方法。采用遗传算法,以应力和位移为约束条件,以工程造价为目标函数,建立了土钉支护结构的优化设计数学模型,并编制了相应的计算程序,通过算例分析,并基于规范法的优化设计结果相比较,得出本文的设计方法更为合理的参考结论。  相似文献   

利用测井资料自动识别藻灰岩   总被引：3，自引：0，他引：3  

张振城  孙建孟  马建海  张炜  苏远大 《吉林大学学报(地球科学版)》2005,35(3):382-388

藻灰岩在测井曲线图上具有不同于其它岩性的特征,据此确定了7种测井参数(自然伽玛、自然电位、井径、声波时差、补偿中子、补偿密度及深电阻率),将测井数据归一化后得到了相应的岩性判别样本参数。利用F-Means中速度较快的聚类迭代(LBG)算法对研究样本进行分类,优选了一组数据用于判别分析。在进行Q因子分析的基础上建立了用于岩性判别的3个判别函数,并对花土沟油田某井段进行了岩性识别预测分析。  相似文献   

无单元法布点优化的一种新方法     

邓俊晔  徐卫亚 《岩土力学》2007,28(9):1841-1847

研究了无单元法中单个影响域内的布点形式对误差的影响,提出了半径权值的概念。在经过充分的数值计算后,给出在半径权值对无单元法插值结果的精度的影响值的大小。研究对优化无单元法的节点布置、减小模拟误差有很大的作用,并且使得影响域的大小不再依靠点数的多少来确定,避免了影响域过大的情况和为了单个影响域内有足够多的插值点而使得整体插值点数目过多的弊端。运用单个区域内的插值点健康度的理论,研究了整个区域布点对无单元法模拟函数--滑动最小二乘法模拟精度的影响,并运用遗传算法对整个布点区域上的插值点进行了优化,给出了区域上的优化值。通过一个实例,得到一个具有普遍意义的插值点优化值与插值点密度的关系,并给出无单元法布点的一般性原则。  相似文献   

现代测量数据显示交互技术研究   总被引：2，自引：2，他引：0  

花向红  万剑华 《测绘工程》2000,9(3):12-14

介绍完成图像数据输出的有关算法,并主要讨论了交互技术的理论和方法,为最终实现测量数据可视化提供了技术基础。  相似文献   

滑坡预报的BP-GA混合算法   总被引：15，自引：3，他引：12  

吴承祯  洪伟 《山地学报》2000,18(4):360-364

提出了滑坡位移预报的一种改进人工神经网络方法－ＡＮＮ－ＧＡ法,与传统的人工神经网络方法相比,该方法加快一网络的学习速度,提高了滑坡位移的预报精度。同时它是一种面向数据的方法,适合于不同地区不同条件下滑坡的预报。两例滑坡预报平均相对误差分别为３．５５％和１．９３％,明显估于传统的ＢＰ算法（分别为１１．３５％和７．２４％）及ＧＰ改进方法（分别为３．９６％和２．６５％）,表明该方法具有科学性、可行性和有  相似文献