共查询到19条相似文献，搜索用时 125 毫秒
1.
针对Noah-MP模型多参数化方案、模拟结果不确定性范围难以确定的特点,选取北疆地区具有代表性的阿勒泰站气象资料作为模型驱动数据,探讨了积雪对多参数化方案的敏感性。在不考虑模型参数和驱动数据不确定性的条件下,设计了集合数为13824的多参数化方案集合模拟试验。选用Natural selection方法对物理过程的敏感性进行分析,并在敏感性分析结果的基础上进一步讨论了模拟结果的不确定性。结果表明:积雪对地表热交换、雨雪分离、土壤温度底层边界条件和第一层积雪或土壤时间方案4个物理过程敏感;在不考虑驱动数据和模型参数不确定性的条件下,多参数化方案集合模拟试验中的不确定性主要来源于敏感物理过程。去除敏感物理过程中能够明显降低模拟性能的参数化方案后,集合模拟结果的不确定性大幅减小。最后,根据分析结果构建了该站雪深和雪水当量模拟的最优参数化方案组合。 相似文献
2.
土壤水分对土壤参数的敏感性及其参数优化方法研究 总被引：2，自引：0，他引：2
利用2008年1月1日至2009年9月31日黑河流域阿柔冻融观测站的气象和土壤水分数据,采用基于方差的多参数敏感性分析方法研究通用陆面模型(Common Land Model,CoLM)模拟的土壤水分对土壤质地(砂土和黏土)的敏感性,进而采用SCE-UA参数优化算法分别优化土壤质地和土壤水力参数,分析不同优化策略对土壤水分模拟结果的影响。研究结果表明,浅层土壤水分对土壤质地较为敏感,敏感性系数达到了0.45以上,并且砂土含量对土壤水分的影响更为显著;利用SCE-UA算法优化土壤质地或土壤水力参数都可以有效地提高土壤水分的模拟精度,优化土壤水力参数易产生"异参同效"现象,而优化土壤质地能够使土壤水力参数的取值范围更加合理。 相似文献
3.
基于围岩力学参数概率分布模型的变形敏感性灰关联分析 总被引：1，自引：0，他引：1
为了给布伦口-公格尔水电站地下洞室某标段围岩稳定性分析的参数选取提供可靠的理论依据,综合考虑岩体参数的空间变异性,针对常规敏感性分析方法所存在的不足,运用三维离散元计算程序,提出了基于围岩力学参数概率分布模型的变形敏感性灰关联分析方法。该方法以岩体密度?、弹性模量E、泊松比?、黏聚力c、内摩擦角φ及节理内摩擦角φj等6个围岩力学参数作为因素序列,拱顶下沉量作为目标序列,分析影响因素在整个定义区间内的变化对围岩拱顶下沉的敏感程度。结果表明：密度是最敏感因素,其次是弹性模量、黏聚力和泊松比,而内摩擦角以及节理内摩擦角敏感性最小。最后,将常规灰关联敏感性分析与该方法计算结果进行对比,结果表明：除密度、内摩擦角和节理内摩擦角一致外,其余参数敏感性均与结论不一致。因此,文中方法在考虑实际参数概率分布的基础上能够更加准确、合理地对参数进行综合评价。 相似文献
4.
滑坡参数敏感性分析是滑坡机理分析和定量评价的基础。滑坡参数敏感性分析有多种方法,然而采用不同方法所得的分析结果是否一致,目前尚不清楚。本文以具有流变特征的甘肃省舟曲县泄流坡滑坡为例,采用敏感性系数法、敏感度函数法和正交试验法等3种最常用方法分析滑坡位移速率对滑带力学参数的敏感性。对比分析发现,3种方法识别出的最敏感参数均为Maxwell黏度,而滑坡对其他参数的敏感性排序却不尽相同。由于敏感性系数法和敏感度函数法适用于参数较少的情况,所以对于受多个流变力学参数控制的缓慢活动性滑坡,基于正交试验法所得的敏感性分析结果相对更为合理。 相似文献
5.
针对广义Hoek-Brown准则参数敏感性分析单因素法的局限性,提出利用正交试验法来研究准则参数对岩体力学参数的影响,该方法可以对各因素的影响进行综合性分析,避免单因素法的片面性。以龙桥特大桥5#拱座所在边坡为工程背景进行了基于正交试验的准则参数敏感性分析。结果表明:地质强度指标GSI对岩体的变形参数Em的影响最显著; 岩石抗压强度ci和岩体扰动系数D对岩体的强度参数C、的影响最显著; 总体来说,岩体力学参数对地质强度指标GSI与岩石抗压强度ci最敏感,对岩体扰动系数D次之,最后为岩石的Hoek-Brown参数mi; 并且准则参数之间无交互作用,相对独立。 相似文献
6.
基于影响因素分布模型的滑坡稳定性敏感分析 总被引：1，自引：0，他引：1
提出了基于影响因素分布模型的滑坡稳定性敏感分析方法,该法用于分析影响因素在整个定义域内对滑坡稳定性的敏感程度,以滑坡影响因素为子序列,以其稳定性系数为目标序列,根据子序列的累积分布函数求影响因素区间概率函数,与目标序列差值乘积加和得到敏感性综合决策值。以三峡库区奉节县太山庙滑坡为例,经类比统计得到滑带土抗剪强度参数的分布函数,通过经验分析得到地震水平加速度和库水位变化的分布函数,应用该法计算得到影响因素中对滑坡稳定性最敏感的因素。以内摩擦角为例,分析了影响因素方差与滑坡稳定性敏感分析结果的关系。 相似文献
7.
东北半干旱地区流域分布式水文模拟——以洮儿河流域为例 总被引：1，自引：0，他引：1
以东北半干旱地区典型流域-洮儿河流域为研究对象,应用SWAT模型对流域水文过程进行了模拟研究;选择流域上游子流域和中下游子流域分别进行参数敏感性分析,识别出影响模拟结果的敏感参数,研究发现部分参数敏感性存在空间变异性,分析主要原因在于气候和下垫面的空间异质性导致了流域上下游产流模式存在差异。采用1988-1997年水文气象数据进行模型率定和验证,结果表明：干流水文站月流量过程率定期Nash-Sutcliffe 效率系数平均值为0.78,验证期为0.72,相关系数都达到0.86以上,水量误差大多在20%以内,对日过程的模拟也有较高的精度;枯水年模拟结果较差,主要是因为流域降水站数量不够,难以反映降水的时空分布。对于水文、气象等资料相对缺乏的东北半干旱地区,SWAT模型的模拟结果总体令人满意,可以应用于与流域径流相关的各种模拟分析,研究成果对进一步加强洮儿河流域水资源综合管理提供了依据和手段。 相似文献
8.
黄土骨干曲线模型比较分析 总被引：2，自引：0，他引：2
对饱和重塑黄土进行了一系列不同加载条件下的动三轴试验,研究了对每级荷载应用多个滞回圈构造骨干曲线的方法,该方法可以考虑更多的试验信息,减小试验随机性对模拟曲线的影响。并运用该方法对试验数据采用Hardin-Drnevich模型、修正Hardin-Drnevich模型和Martin-Darvidenkov模型3种不同的骨干曲线模型进行数值模拟,分析了不同的骨干曲线模型对试验数据模拟的准确性和参数敏感性。结果表明,在试验条件变化时Hardin-Drnevich模型并不能总是很好地模拟试验骨干曲线,而且在有些情况下偏离较多。修正Hardin-Drnevich模型和Martin-Darvidenkov模型相比于Hardin-Drnevich模型能更好地模拟试验数据。在对不规则动载下黄土动力反应的数值模拟中,可以考虑用修正Hardin-Drnevich模型和Martin-Darvidenkov模型模拟骨干曲线。考虑到Martin-Darvidenkov模型参数对试验数据相对敏感,因此,建议采用修正Hardin-Drnevich模型模拟骨干曲线。 相似文献
9.
垃圾填埋场稳定影响因素敏感性神经网络分析 总被引：2，自引：0，他引：2
垃圾填埋场稳定影响因素的选取和研究是稳定分析的重要组成部分,而确定主次要因素的方法就是进行影响因素敏感性分析。利用BP神经网络结合正交试验设计方法,对填埋场沿衬里滑移破坏的影响因素进行敏感性分析。通过对工程实例的计算,该方法与传统法有着相同的因素敏感性排序,但决定排序的极差值有所不同。由于该法能考虑多因素同时变化,故其极差值的大小更能反映因素敏感程度的差异。BP神经网络结合正交试验设计法与传统法相比能节省计算工作量。研究结果显示,影响填埋场滑移稳定性的最主要参数为复合衬垫层间最小摩擦角和垃圾的堆填坡角。因素敏感性排序的确定为填埋场的优化设计、施工、试验、运营管理提供了理论依据。 相似文献
10.
参数敏感性分析与试验方案优化 总被引：20，自引：2，他引：20
在单因素敏感性分析的基础上,定义了无量纲形式的敏感度函数和敏感度因子,使得多因素敏感性分析具有可比性。作为算例,对拉西瓦地下工程的稳定性进行了敏感性分析。结果表明,水平向地应力σ_x和岩体弹性模量E是影响地下主厂房高边墙水平向变形的敏感因素。分析还表明,敏感因素与基准参数集有关,基准参数集不同,结论将有差异。本文还提出了试验方案优化的概念,并指出参数敏感性分析是试验方案优化的基础。 相似文献
11.
The present paper validates two alternative global sensitivity analysis methods, namely variance-based and elementary effect, for the purpose of detecting key subsoil parameters that influence the output of mechanized tunnel finite element simulation. In the elementary effect method, a strategy for considering the dependencies, that result from a set of constraints between different parameters, is proposed. Moreover, because the numerical implementation of variance-based sensitivity estimates, in particular, has been proven to require intensive evaluations of the system under investigation, a practical surrogate modeling technique is utilized. This technique is based on quadratic polynomial regression and represents a reliable approximation of the computationally expensive mechanized tunnel simulation. Furthermore, a convergence analysis based on Central Limit Theorem for the numerical implementation of the methods is introduced. The adopted analysis highlights model evaluations needed for the sensitivity measures to converge, as well as the uncertainty involved in these measures. 相似文献
12.
Identification of a karst system’s intrinsic hydrodynamic parameters: upscaling from single springs to the whole aquifer 总被引：1，自引：1，他引：0
Andreas Hartmann Martin Kralik Franko Humer Jens Lange Markus Weiler 《Environmental Earth Sciences》2012,65(8):2377-2389
For water management purposes, information about an entire aquifer system is generally more important than information about
a specific spring. Since a karstic aquifer system might drain to several outlets, conclusions derived from a single spring
can be misleading for characterization and modeling. In this study we apply a conceptual model to an Alpine dolomite karst
system in Austria. The particular challenge was that several small springs with strongly varying hydrological behavior and
diffuse flow into surrounding streams drain this system. Instead of applying the model to a single spring, it was calibrated
simultaneously to several observations within the system aiming to identify the karst system’s intrinsic hydrodynamic parameters.
Parameter identification is supported by modeling the transport of water isotopes (δ18O). The parameters were transferred to the whole system with a simple upscaling procedure and a sensitivity analysis was performed
to unfold influence of isotopic information on parameter sensitivity and simulation uncertainty. The results show that it
is possible to identify system intrinsic parameters. But the sensitivity analysis revealed that some are hardly identifiable.
Only by considering uncertainty reasonable predictions can be provided for the whole system. Including isotopic information
increases the sensitivity of some intrinsic parameters, but it goes along with a sensitivity decrease for others. However,
a possible reduction of prediction uncertainty by isotopic information is compensated by deficiencies in the transport modeling
routines. 相似文献
13.
Quantifying Asymmetric Parameter Interactions in Sensitivity Analysis: Application to Reservoir Modeling 总被引：1，自引：1，他引：0
In this paper, a new generalized sensitivity analysis is developed with a focus on parameter interaction. The proposed method is developed to apply to complex reservoir systems. Most critical in many engineering applications is to find which model parameters and parameter combinations have a significant impact on the decision variables. There are many types of parameters used in reservoir modeling, e.g., geophysical, geological and engineering. Some parameters are continuous, others discrete, and others have no numerical value and are scenario-based. The proposed generalized sensitivity analysis approach classifies the response/decision variables into a limited set of discrete classes. The analysis is based on the following principle: if the parameter frequency distribution is the same in each class, then the model response is insensitive to the parameter, while differences in the frequency distributions indicate that the model response is sensitive to the parameter. Based on this simple idea, a new general measure of sensitivity is developed. This sensitivity measure quantifies the sensitivity to parameter interactions, and incorporates the possibility that these interactions can be asymmetric for complex reservoir modeling. The approach is illustrated using a case study of a West Africa offshore oil reservoir. 相似文献
14.
不同深度处的含水介质温度时序资料振幅比或相位滞后能用来计算地下水垂向流速,典型的解析模型是Hatch模型。为了评价Hatch模型的参数灵敏度,采用局部灵敏度分析方法确定该模型的主要影响因子及相关参数与模型响应的依存关系,再由全局灵敏度分析方法评价参数共同作用对模型计算结果的影响。灵敏度分析结果表明:Hatch模型精度的主要影响因子是测点距离（Δz）,其次是介质比热容（ρscs）和有效孔隙度（ne）,而基准热传导系数（λ0）和热弥散度（β）的影响甚微。基准热传导系数和热弥散度与计算流速呈负相关,其余参数则与之呈正相关。因此在实践中,需保证测点距离的准确性,而对基准热传导系数和热弥散度可取经验值。 相似文献
15.
The water and energy transfer of land surface is complex due to its large spatial and temporal variability. The modeling and simulation is an important means to study land water and energy transfer, but most selection and analysis of model parameters are empirical and qualitative. This paper has proposed a method of quantitatively identifying the most influential parameters of Common Land Model through Sobol?? sensitivity analysis. Considering sensible heat flux as the model output, the first order and total sensitivity indices of 25 model input parameters are estimated using an improved Sobol?? method. The simulated results are resampled using a bootstrapping method and the corresponding sensitivity indices are calculated. Confidence intervals for the bootstrapping sensitivity indices are estimated by using a percentile method. The results show that the parameters phi0 and porsl are the most important parameters, followed by ref(2,1), tran(2,1) and bsw. Five out of 25 parameters need to have an accurate evaluation, while the other parameters are fixed to a certain value. The sensitivity indices of parameters phi0 and porsl are decreasing after precipitation, while the sensitivity indices of parameters tran(2, 1) and ref(2, 1) are increasing after precipitation. 相似文献
16.
The numerical modeling of unsaturated soil processes is becoming more prevalent worldwide. Although numerical modeling is
becoming increasingly accepted in geotechnical engineering practice, care must be exercised and improper modeling techniques
and procedures must be avoided. Many issues such as nodal resolution and imperfect convergence can result in inaccurate solutions.
Unfortunately, analyses of highly nonlinear unsaturated soil flow and slope stability models can significantly increase the
modeling time required. As a result, there is a trend to reduce the number of model runs. Results are often presented to client
as single model runs or simplistic sensitivity analysis. This paper presents methodologies for applying probabilistic methods
to unsaturated soils seepage and slope stability analysis models. The focus is on the application of the alternative point
estimate method to practical problems in such a way as to minimize the number of model runs. The demonstration of a successful
application to a waste rock pile is presented. 相似文献
17.
Stochastic Modeling Approach for the Evaluation of Backbreak due to Blasting Operations in Open Pit Mines 总被引：2，自引：0，他引：2
Backbreak is an undesirable side effect of bench blasting operations in open pit mines. A large number of parameters affect backbreak, including controllable parameters (such as blast design parameters and explosive characteristics) and uncontrollable parameters (such as rock and discontinuities properties). The complexity of the backbreak phenomenon and the uncertainty in terms of the impact of various parameters makes its prediction very difficult. The aim of this paper is to determine the suitability of the stochastic modeling approach for the prediction of backbreak and to assess the influence of controllable parameters on the phenomenon. To achieve this, a database containing actual measured backbreak occurrences and the major effective controllable parameters on backbreak (i.e., burden, spacing, stemming length, powder factor, and geometric stiffness ratio) was created from 175 blasting events in the Sungun copper mine, Iran. From this database, first, a new site-specific empirical equation for predicting backbreak was developed using multiple regression analysis. Then, the backbreak phenomenon was simulated by the Monte Carlo (MC) method. The results reveal that stochastic modeling is a good means of modeling and evaluating the effects of the variability of blasting parameters on backbreak. Thus, the developed model is suitable for practical use in the Sungun copper mine. Finally, a sensitivity analysis showed that stemming length is the most important parameter in controlling backbreak. 相似文献
18.
程昊 《矿物岩石地球化学通报》2005,24(2):148-152
对石榴子石冷却速率计中的几个重要参数误差分析结果表明，在慢速冷却的情况下，由测量数据误差所致的偏差可以忽略不计。但当冷却速率较大时，误差对模拟结果的影响则非常显著。然而，若采用现代分析仪器，由定位导致的模拟误差也可以完全忽略。空间测量的偏差往往使模拟得到的岩石冷却速率比实际值小得多；初始温度估计的偏差会使模拟结果产生很大的变化；扩散系数的选择对模拟结果影响也颇大。因此．具体情况下需仔细选取那些实验条件与所研究的具体地质情况最为相似的实验数据得到的模拟结果才是合理的。只有在合理的计算和选取参数以及可靠的测试技术的情况下，得到的模拟结果才具有地质意义。 相似文献
19.
This paper focuses on the sensitivity analysis for coupled thermo–hydro–mechanical problems employing both local and global sensitivity methods. A derivative‐based method is used in the local sensitivity approach, whereas the random balance designs method is used for the global sensitivity analysis. The main goal is to investigate the effect of uncertainties in the constitutive parameters on the results from nonlinear coupled thermo–hydro–mechanical analyses of unsaturated soil behavior whose modeling generally involves large sets of constitutive relations. Knowing the parameter sensitivity allows to qualitatively assess the validity of the results obtained by computational simulations of high‐risk situations, for example, emerging nuclear waste repositories. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献