共查询到20条相似文献，搜索用时 312 毫秒
1.
An overview is given about up-to-date techniques for slope stability and deformation analysis as well as mass flow phenomena simulation. The paper concentrates on a few aspects in respect to the use of numerical modeling techniques, especially in relation to the shear strength reduction techniques, discontinuum modeling, probabilistic concepts, the combination of GIS and numerical modeling as well as sophisticated hydro-mechanical coupling with time-dependent material behavior. At present these topics are preferred topics of scientific and technical research. 相似文献
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杨凌农业高新技术产业示范区南临渭河，三维渗流数值模拟结果表明，拟建于渭河漫滩和一级阶地上的两个地下水水源地的开采将大大地激发渭河水对地下水的补给，使得已受污染的渭河水对拟建水源地的水质造成严重威胁。水质模拟结果表明，在未来开采条件下，热电厂水源地、水上运动中心及渭河近岸地带的地下水最容易受到渭河水污染的影响。 相似文献
3.
有限元法与伪谱法混合求解弹性波动方程 总被引：6，自引：0，他引：6
在地震波场数值模拟中,有限差分法、有限元法和伪谱法都是常用的基本方法,但它们各有不同的适应性和优缺点,如有限差分法、有限元法都存在减弱网格频散和提高计算效率的矛盾,而伪谱法的网格频散小且计算效率高.有限差分法和伪谱法在处理地表结构复杂或地表剧烈起伏以及地下结构复杂的情况时存在较大的难度,而有限元法可较为理想地拟合起伏地表和任意弯曲界面,且可方便地处理自由边界条件和界面边界条件.尝试将有限元法和伪谱法相结合,形成地震波场数值模拟的一种混合方法,利用二者的优点,克服二者的缺点,达到既减弱网格频散又提高计算精度和效率的目的.并采用所谓的‘过度区域‘技术解决两种不同算法的衔接问题.模拟实例表明,给出的混合模拟方法不失为弹性波场数值模拟的一种有效方法. 相似文献
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本文介绍了面向虚拟地理环境的基于概念模型的图形化地理建模方法,利用面向对象方法设计了可扩展的图形化地理建模的体系架构,并详细介绍了实现图形化建模的关键技术。应用成果表明:该体系架构具有高度的可扩展性和适应性,支持基于模型组件构建复合地理分析模型,有助于对地理现象、地理机理和地理过程准确认知。 相似文献
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M. Santosh 《中国海洋大学学报(英文版)》2012,11(3):257-266
The fields of structural geology and tectonics have witnessed great progress over the last decade and are poised for further expansion in the future. One of the significant breakthroughs is the establishment of the ’Beyond Plate Tectonics Theory’ where a combination of conceptual models and numerical modeling on plume tectonics and plate tectonics has enabled new insights into the structural and tectonic architecture and processes in the deep interior and deep sea. This paper synthesizes developments of structural geology and tectonics from a macroscopic perspective in deep interior and deep sea. Four key techniques are also reviewed: satellite altimetry for surface structures in deep-sea multi-beam sea-floor mapping; tomography for tectonics of the deep interior; diverse modeling approaches and software for unfolding dynamic evolution; and techniques for HT/HP experiments on material rheology and in situ component measurements. 相似文献
6.
岱崮地貌是继岩溶地貌、丹霞地貌、张家界地貌、嶂石岩地貌之后的中国第5种岩石地貌,作为一种新命名的地貌类型,岱崮地貌具有极大的美学价值和科研价值。但对其的研究和开发却相对滞后。该文介绍了岱崮地貌的研究现状、分布及其形成过程、发育阶段等,岱崮地貌的分布规律、形态特征、组成结构,其演变趋势与模式及其形成机制等,是其学术研究的核心问题。加强对岱崮地貌的研究,不仅能够改变地貌学中关于方山研究的薄弱局面,丰富大陆风化及陆地碳循环研究,而且可深化对沂蒙山区地质地貌条件、生态环境特点的认识,也可为申报国家地质公园和世界自然遗产提供科学支撑。 相似文献
7.
《山地科学学报》2015,(4)
Recent advances in computer with geographic information system(GIS) technologies have allowed modelers to develop physics-based models for modeling soil erosion processes in time and space.However, it has been widely recognized that the effect of uncertainties on model predictions may be more significant when modelers apply such models for their own modeling purposes.Sources of uncertainty involved in modeling include data, model structural, and parameter uncertainty.To deal with the uncertain parameters of a catchment-scale soil erosion model(CSEM) and assess simulation uncertainties in soil erosion, particle filtering modeling(PF) is introduced in the CSEM.The proposed method, CSEM-PF, estimates parameters of non-linear and non-Gaussian systems, such as a physics-based soil erosion model by assimilating observation data such as discharge and sediment discharge sequences at outlets.PF provides timevarying feasible parameter sets as well as uncertainty bounds of outputs while traditional automatic calibration techniques result in a time-invariant global optimal parameter set.CSEM-PF was applied to a small mountainous catchment of the Yongdamdam in Korea for soil erosion modeling and uncertainty assessment for three historical typhoon events.Finally, the most optimal parameter sets and uncertainty bounds of simulation of both discharge and sediment discharge at each time step of the study events are provided. 相似文献
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The Webb-Resio-Tracy (WRT) method for exact computation of the non-linear energy transfer rate was implemented in MASNUM-WAM, which is a third-generation wave model solving the discrete spectral balance equation. In this paper, we describe the transformation of the spectral space in the original WRT method. Four numerical procedures were developed in which the acceleration techniques in the original WRT method, such as geometric scaling, pre-calculating, and grid-searching, are all reorganized. A series of numerical experiments including two simulations based on real data were performed. The availability of such implementation in both serial and parallel versions of the wave model was proved, and a comparison of computation times showed that some of the developed procedures provided good efficacy. With exact computation of non-linear energy transfer, MASNUM-WAM now can be used to perform numerical experiments for research purposes, which augurs well for further developments of the model. 相似文献
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Jianjun NIU Xiaopei ZHANG Lizhi DU College of Construction Engineering Jilin University Changchun China 《东北亚地学研究》2008,11(4):232-236
Multi-electrodes Resistivity Imaging Survey （MRIS） is an array method of electrical survey. In practice how to choose a reasonable array is the key to get reliable survey results. Based on four methods of MRIS such as Wenner, Schlumberger, Pole-pole and Dipole-dipole the authors established the model, by studying the result of the forward numerical simulation modeling and inverse modeling, and analyzed the differences among the different forms of detection devices. 相似文献
13.
《世界地质(英文版)》2008,11(4)
Multi-electrodes Resistivity Imaging Survey (MRIS) is an array method of electrical survey. In practice how to choose a reasonable array is the key to get reliable survey results. Based on four methods of MRIS such as Wenner, Schlumberger, Pole-pole and Dipole-dipole the authors established the model, by studying the result of the forward numerical simulation modeling and inverse modeling, and analyzed the differences among the different forms of detection devices. 相似文献
14.
Seismic wave modeling is a cornerstone of geophysical data acquisition, processing, and interpretation, for which finite-difference methods are often applied. In this paper, we extend the velocity-pressure formulation of the acoustic wave equation to marine seismic modeling using the staggered-grid finite-difference method. The scheme is developed using a fourth-order spatial and a second-order temporal operator. Then, we define a stability coefficient (SC) and calculate its maximum value under the stability condition. Based on the dispersion relationship, we conduct a detailed dispersion analysis for submarine sediments in terms of the phase and group velocity over a range of angles, stability coefficients, and orders. We also compare the numerical solution with the exact solution for a P-wave line source in a homogeneous submarine model. Additionally, the numerical results determined by a Marmousi2 model with a rugged seafloor indicate that this method is sufficient for modeling complex submarine structures. 相似文献
15.
渗流域内应用拉普拉斯变换(LT)建立相应的有限分析(FAM)方程,顾及渗流域内地下水流的初始条件和边界条件,可在LT空间构成一个封闭的以水头像函数为变量的线性方程组。将此方程组所得的解,通过Stehfest数值反演公式,可归化为时间域的解(水头)。由于时间t被隐含在数值方程内,从而克服了传统数值法按时段(△t)逐步迭代的缺陷,提高了计算效率,也为用嵌入法建立地下水流管理模型提供了一条捷径。 相似文献
16.
《山地科学学报》2021,(9)
The in-situ stress field is a key factor controlling the successful construction of a large number of underground structures in mountainous areas, and is intensively affected by the mountainvalley topography. The effects of mountain-valley morphology(the width of the mountain top platform, mountain height, slope angle, and width of the valley bottom) on the distribution of the in-situ stress field were analyzed and interpreted using numerical modeling techniques, where the spatial distribution and maximum values of the horizontal and vertical stresses were analyzed. The results showed that there existed a critical value of the topographic influence depth, where the in-situ stress distribution varied significantly as mountain-valley morphology, after which the influence diminishes. Tectonic action has a more remarkable influence on the in-situ stress distribution than gravitational action under the same mountain-valley morphology. Moreover, the relationships between the magnitudes of these stress components and the morphology variables are described using empirical formulas, which can be directly applied to different topographies to rapidly achieve a rational estimation. The findings of this study can be very useful for quickly understanding the in-situ stress distribution and as stress measurement guidelines. 相似文献
17.
Numerical simulation of the hydrodynamics within octagonal tanks in recirculating aquaculture systems 总被引：2，自引：0，他引：2
A three-dimensional numerical model was established to simulate the hydrodynamics within an octagonal tank of a recirculating aquaculture system.The realizable k-s turbulence model was applied to describe the flow,the discrete phase model(DPM) was applied to generate particle trajectories,and the governing equations are solved using the finite volume method.To validate this model,the numerical results were compared with data obtained from a full-scale physical model.The results show that:(1) the realizable k-e model applied for turbulence modeling describes well the flow pattern in octagonal tanks,giving an average relative error of velocities between simulated and measured values of 18%from contour maps of velocity magnitudes;(2) the DPM was applied to obtain particle trajectories and to simulate the rate of particle removal from the tank.The average relative error of the removal rates between simulated and measured values was 11%.The DPM can be used to assess the self-cleaning capability of an octagonal tank;(3) a comprehensive account of the hydrodynamics within an octagonal tank can be assessed from simulations.The velocity distribution was uniform with an average velocity of 15 cm/s;the velocity reached0.8 m/s near the inlet pipe,which can result in energy losses and cause wall abrasion;the velocity in tank corners was more than 15 cm/s,which suggests good water mixing,and there was no particle sedimentation.The percentage of particle removal for octagonal tanks was 90%with the exception of a little accumulation of 5 mm particle in the area between the inlet pipe and the wall.This study demonstrated a consistent numerical model of the hydrodynamics within octagonal tanks that can be further used in their design and optimization as well as promote the wide use of computational fluid dynamics in aquaculture engineering. 相似文献
18.
Christopher N.K. Mooers Inkweon Bang 《中国海洋大学学报(英文版)》2005,4(4):288-292
The Florida Current （FC） largely fills the Straits of Florida and is variable on a broad spectrum of time and space scales. Some portions of the variability are due to variable forcing by tides, winds, heating/cooling, and throughflow; other portions are due to intrinsic instabilities of the FC. To predict, as well as to better understand this complex regime, a nowcast/forecast system （East Florida Shelf Information System （EFSIS）） has been implemented and assessed （http：//efsis. rsmas. miami. edu）. EFSIS is based on an implementation of the Princeton Ocean Model （POM） with mesoscale-admitting resolution on a curvilinear grid. It is forced by a mesoscale numerical weather prediction system （called Eta） run operationally by the National Centers for Environmental Prediction （NCEP）, eight tidal constituents from a global tidal model, and lateral boundary conditions from an operational global ocean prediction model, i.e., the Navy Coastal Ocean Model （NCOM）. Real-time observations of coastal sea level, coastal sea surface temperature, coastal HF radar-derived surface current maps, and FC volume transport are used to verify and validate EFSIS. EFSIS is part of an evolving strategy for real-time predictive coastal ocean modeling methodology, and for fostering the understanding of the variability of the regime on several time and space scales. Here, some of the verification and validation results are provided, as well as diagnostic analyses of dynamical processes. The central point is that an example is provided of a ＇scientific revolution＇ in progress that combines real-time observations and numerical circulation models to yield a credible sequence of synoptic views of coastal ocean circulation for the first time. 相似文献
19.
用于重力向下延拓的离散化方法 总被引：3，自引：2，他引：1
孙文科 《大地测量与地球动力学》2004,24(1):9-18
泊松积分通常用于把重力值从地球表面转化到大地水准面(即称之为重力向下延拓)的过程中。由于这是一个反问题，一些数字技术比如将积分离散化为一个线性方程组是必需的。目前，已经提出了两种离散化方案(单点和双重平均)。虽然这两种方案在数学上都是可解的，但用它们处理相同的输入地面重力值时，却得出不同的大地水准面上的重力值。这种差异的产生是由于对泊松核函数的不同离散化方法造成的，而且这一问题尚未引起足够的关注。实际上，数学上的可解性并不能保证得到正确的解。问题在于此方程组是否构成得很好，或者说，离散化是否合理。因而本文研究泊松积分的离散方法。为此目的，本文提出一个单点平均的方案来对泊松积分进行估值。单点平均方案基本上与双点平均方案是相同的，但它在计量上更为简单，因为其计算工作大为减少。比较单点和双点平均方案后表明，对于一个有限的地表网格范围情况，单点离散方案会带来严重的理论问题，因为会相当大地低估大地水准面上的重力值甚至在极端情况时会给出不正确的结果。我们得到，仔细构成离散方程组的系数矩阵比应用单点重力值作为输入远为重要。 相似文献
20.
《山地科学学报》2021,(7)
Mountain block recharge(MBR), an important water resource, is a widespread process that recharges lowland aquifers. However, little is known about MBR due to the limited climatic and geologic data in mountainous regions such as the northern central foothills of Tianshan. Here, we present an approach to quantify MBR through the combination of water balance calculations and numerical modeling. MBR calculated from the water balance in the data-limited Tianshan Mountains is employed as a fluid-flux boundary condition in the numerical model of the plain. To verify the performance of the model, mean absolute error and root mean square error were used. Results show that the volume of water that is recharging the aquifer via MBR is 107.29 million m~3/yr, accounting for 2.2% of the total precipitation that falls in the mountains. Additionally, 53.3% of that precipitation enters the plain aquifer via runoff, totaling 2,652.68 million m~3/yr. The lower volume of MBR is attributed to a major range-bounding anticline with apparent low permeability in the Tianshan Mountains. Through numerical modeling of groundwater, MBR coming from bedrock was found to be significant, accounting for 14% of total aquifer recharge in the plain, only after the portion of runoff seepage. This research contributes to a deeper understanding of MBR, and may provide instructions for estimating groundwater recharge in arid and semi-arid areas. 相似文献