共查询到20条相似文献，搜索用时 218 毫秒
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云南中北部地区水平形变应变场研究 总被引：3，自引：0，他引：3
根据云南地区1999－2001年的GPS观测求得的水平变场和应变场，研究了云南北部地区的形变和应变特征。研究表明，研究区的中部地壳位移量较小，比较稳定，西部和东部位移量较大，活动性较强，应变场揭示出，本区地壳及其各次一级断块的主压应变轴方向都为NW－SE方向，主张应变轴方向为NE－SW向研究区北部以张应变为主导，中部和南部压变变占主导地位，剪应变等值线的展布方向与活动断裂走向基本一致。断层活动的应变应力场与各个断裂带所处的构造位置有关，活动性质不尽相同。 相似文献
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地震灾场的模拟与模拟控制问题研究：（Ⅱ）地震灾场的模拟控制 总被引：1，自引：0，他引：1
根据对城市火灾的大量统计资料分析，本文建立了以地震次生火灾为的地震灾场灾度量化指标。在此基础上，根据地震灾场控制的特点，提出了两类基本的地震灾模拟控制问题。文中以地震灾场仿真技术为基础，发展了模拟控制算法，并以实例验证了算法的可行性。 相似文献
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从地震灾场的系统特性入手，简述了地震灾场系统仿真的基本思想，并重点以开封市为对象，进行了详细的案例分析。 相似文献
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场方程是能够表述半空间地震波场的整体特征.波动方程、速度方程和能量方程.通过分析可知每个场方程都具有各自的“场方程矩阵”.能量方程能够对所有场方程矩阵进行综合和贯通，给出了能量方程以“弹性矩阵”为核心的普适性表达形式.最后，运用矩阵的正定二次型理论阐述了“能量矩阵与弹性矩阵”之间一致的对称性和正定性.能量矩阵蕴含的动态力的平衡关系、速度的时间_空间分布和能量的传播及变化的物理意义，能够从能量矩阵的正定二次型特性表述出来.本文研究分析问题的方法完全适用于复杂介质模型，相关的认识和结论可以拓展到均匀黏弹性各向同性介质、均匀弹性各向异性介质、均匀黏弹性各向异性介质以及比奥饱和流体介质. 相似文献
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地震灾场的模拟与模拟控制问题研究（I）地震灾场模拟 总被引：4，自引：0，他引：4
本文将离散事件系统仿真的方法引入地震工程研究之中，在论述地震灾场模拟与离散事件系统仿真的共性与差异的基础上，以城市地震次生火灾的发生与扑救过程为背景，发展了场，时域复合仿真模型，提出了城市地震灾场的综合模拟算法，实例研究表明，本文建议的地震灾场模拟算法可以揭示复合型工程系统地震反应的一系列特征参数。 相似文献
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通过建立目标函数和Levenber-Marquardt迭代等数学方法求出杂多地震的多个震源机制解的中心解，并用Wells和Coppersmith的统计公式估算出断层面大小和滑动量，进一步计算出主震所产生的同震位移场及应变场。结果表明：(1)推断节面II(走向342.12°,倾角70.62°,滑动角是-175.99°)是本次地震的主断层面。(2)在水平位移场方面，震中东北物质向震中涌入，西北、东南物质向外涌出；在垂直位移场方面，震中东北部为沉降，东南部为隆升。综合分析认为，水平位移大于垂直位移，判断此次地震为走滑型。(3)体应变在震中东北侧呈现压缩，在震中西北、东南两侧呈现伸张，北向应变、东向应变、北东向应变在震中均呈现八花瓣样式分布。(4)体应变形态与面应变分布大体相同，表现在面应变继承体应变。本研究可为地震对周围的影响，地震发生原因提供分析依据。 相似文献
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利用ISEE－1和ISEE-2飞船观测的磁场数据，分析了地球内磁层场向电流的统计特征，包括场向电流的空间（L值和地方时）分布；流进和流出电离层的场向电流随地方时的变化；场向电流发生率与地磁活动水平（以AL指数表征）、行星际磁场（IMF）Bz的关系，电流强度和密度随地磁活动水平的变化等．发现，场向电流大都发生在夜间，且集中在L为6-10区域内，场向电流发生率，强度和密度随地磁活动增强而增大，行星际磁场南向时的发生率远远高于北向时的发生率．这些结果表明，内磁层场向电流的产生是太阳风和磁层、电离层间电动耦合增加的结果． 相似文献
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地震灾场的模拟与模拟控制问题研究（Ⅰ）地震灾场模拟 总被引：3，自引：0，他引：3
本文将离散事件系统仿真的方法引入到地震工程研究之中．在论述地震灾场模拟与离散事件系统仿真的共性与差异的基础上，以城市地震次生火灾的发生与扑救过程为背景，发展了场、时域复合仿真模型，提出了城市地震灾场的综合模拟算法．实例研究表明，本文建议的地震灾场模拟算法可以揭示复合型工程系统地震反应的一系列特征参数。 相似文献
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Decoupling of the coupled poroelastic equations for quasistatic flow in deformable porous media containing two immiscible fluids 总被引：1，自引：0，他引：1
The study of the poroelastic behavior of sedimentary materials containing two immiscible fluids in response to either applied stress or pore pressure change in a quasistatic limit, i.e., negligible second time-derivatives, is of great importance to many hydrogelogical problems, e.g., land subsidence caused by withdrawal of subsurface fluids. The poroelasticity models developed for analyzing these problems feature partial differential equations that are coupled in the terms describing viscous damping and strain field. To determine closed-form analytical solutions for induced volumetric strain (dilatation) of the solid framework and its interaction with fluid flows, the choice of normal coordinates whose transformation can be performed to decouple these poroelastic equations is highly desirable. In this paper, we show that normal coordinates for decoupling these equations are real-valued and equal to three different linear combinations of the dilatations of the solid and the fluids (or equivalently, three different linear combinations of two individual fluid pressures and solid dilatation). In contrast to fully saturated porous media, it is found that the viscous damping effect must be represented in normal coordinates in the presence of the second fluid. The resulting decoupled equations representing independent motional modes are a Laplace equation and two diffusion equations, which can be solved analytically under a variety of initial and boundary conditions. Thus, after inverse transformation of normal coordinates is performed, the closed-form analytical solutions for induced solid volumetric strain and excess pore fluid pressures can be obtained simultaneously from our decoupled partial differential equations. 相似文献
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《Advances in water resources》1999,23(3):229-237
It can be very time consuming to use the conventional numerical methods, such as the finite element method, to solve convection–dispersion equations, especially for solutions of large-scale, long-term solute transport in porous media. In addition, the conventional methods are subject to artificial diffusion and oscillation when used to solve convection-dominant solute transport problems. In this paper, a hybrid method of Laplace transform and finite element method is developed to solve one- and two-dimensional convection–dispersion equations. The method is semi-analytical in time through Laplace transform. Then the transformed partial differential equations are solved numerically in the Laplace domain using the finite element method. Finally the nodal concentration values are obtained through a numerical inversion of the finite element solution, using a highly accurate inversion algorithm. The proposed method eliminates time steps in the computation and allows using relatively large grid sizes, which increases computation efficiency dramatically. Numerical results of several examples show that the hybrid method is of high efficiency and accuracy, and capable of eliminating numerical diffusion and oscillation effectively. 相似文献
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The constant-head pumping tests are usually employed to determine the aquifer parameters and they can be performed in fully or partially penetrating wells. Generally, the Dirichlet condition is prescribed along the well screen and the Neumann type no-flow condition is specified over the unscreened part of the test well. The mathematical model describing the aquifer response to a constant-head test performed in a fully penetrating well can be easily solved by the conventional integral transform technique under the uniform Dirichlet-type condition along the rim of wellbore. However, the boundary condition for a test well with partial penetration should be considered as a mixed-type condition. This mixed boundary value problem in a confined aquifer system of infinite radial extent and finite vertical extent is solved by the Laplace and finite Fourier transforms in conjunction with the triple series equations method. This approach provides analytical results for the drawdown in a partially penetrating well for arbitrary location of the well screen in a finite thickness aquifer. The semi-analytical solutions are particularly useful for the practical applications from the computational point of view. 相似文献
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定量描述储层特征的物理量称为储层参数,在储层描述工作中储层参数预测是一个重要环节.本文以岩石物理理论为基础研究了利用岩石物理逆建模理论进行储层参数预测的方法.在合理、有效的岩石物理模型的基础上,逆建模方法通过弹性参数的等值面的空间交会可以预测出储层参数.在此基础上提出了一种扩展的岩石物理逆建模方法,在两个不同的储层参数域进行三维岩石物理逆建模,通过逆建模结果的参数域转换可以预测更多的储层参数,为储层特征描述提供了更加充分的数据支持.输入数据的种类对于预测结果的准确性有较大影响,利用本文建立的弹性参数适用性分析方法可以选择出适用性好的弹性参数组合作为输入数据.将本方法应用于模型数据和实际工区数据,取得了较好的预测效果,证明方法具有一定的实用性. 相似文献
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P. Latinopoulos 《Advances in water resources》1984,7(3):137-140
Analytical solutions for groundwater flow in unconfined rectangular aquifers are presented for the case of recharge from rectangular areas. The linearised differential equation of the flow is solved using Laplace and finite Fourier transforms. The problem concerns the response of finite aquifers to periodic (seasonal) recharge schemes of variable duration. Results can be obtained for various combinations of Dirichlet and Neumann boundary conditions and can be easily used in a preliminary study of water resources management. 相似文献
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New Methods for Modeling Laterolog Resistivity Corrections 总被引：1，自引：1，他引：0
Jadwiga Anna Jarzyna Adam Cichy Dezső Drahos Attila Galsa Maria Joanna Bała Andrzej Ossowski 《Acta Geophysica》2016,64(2):417-442
The paper presents methods for laterolog response modeling. In Coulomb’s charges method, Laplace’s equation is solved for the electric field distribution in rock medium with internal boundaries between different resistivity layers. There, the boundary problem is reduced to Fred-holm integral equation of the second kind. The second method uses a finite element array to model apparent resistivity from laterolog. The task is treated as DC problem and the Laplace equation is solved numerically. The presented methods were applied to borehole data covering a typical stratigraphie section of the Fore-Sudetic Monocline in southwestern Poland. Apparent resistivity was calculated using the Coulomb’s charges method and alternatively modeled using a finite element method which gave similar results. Then, a series of linear corrections for borehole, shoulder bed, and filtration effects for apparent resistivity obtained by the Coulomb’s charges method demonstrated the feasibility of calculating true resistivity of virgin and invaded zones. The proposed methods provide a flexible solution in modeling which can be adapted to other logs. 相似文献
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A general analytical solution for flow to a single horizontal well by Fourier and Laplace transforms
The objective of this paper is to present an analytical solution for describing the head distribution in an unconfined aquifer with a single pumping horizontal well parallel to a fully penetrating stream. The Laplace-domain solution is developed by applying Fourier sine, Fourier and Laplace transforms to the governing equation as well as the associated initial and boundary conditions. The time-domain solution is obtained after taking the inverse Laplace transform along with the Bromwich integral method and inverse Fourier and Fourier sine transforms. The upper boundary condition of the aquifer is represented by the free surface equation in which the second-order slope terms are neglected. Based on the solution and Darcy’s law, the equation representing the stream depletion rate is then derived. The solution can simulate head distributions in an aquifer infinitely extending in horizontal direction if the well is located far away from the stream. In addition, the solution can also simulate head distributions in confined aquifers if specific yield is set zero. It is shown that the solution can be applied practically to evaluate flow to a horizontal well. 相似文献
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In mathematical statistical filtering the deconvolution problem can be solved by two different methods:
- 1 by inverse filtering
- 2 by calculating the prediction error.
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J. DOHERTY 《Geophysical Prospecting》1988,36(6):644-668
The theory by which the Surface Integral Equation method may be applied to the solution of electromagnetic transmission boundary value problems is presented. For a 3D target of arbitrary electrical property contrast with its host medium excited by an arbitrary time-harmonic source, two integral equations are derived which need to be simultaneously solved for tangential electric and magnetic source density on the target's surface. If the target is 2D, though still excited by an arbitrary source (the 2½ D case), the problem is best solved in the transform domain for a number of different wavenumbers in the target's strike direction. Then a set of four simultaneous scalar integral equations needs to be solved for the components of the surface source density transforms in the target's strike direction and in the direction of the tangent vector to the target's cross-sectional contour. Examples are presented in which the 2½D problem is solved numerically using the method of moments with piecewise linear basis functions. Although the results generally compare well with analytical solutions, or solutions obtained numerically by other means, errors appear in the calculation of the real response of these targets to excitation by a magnetic dipole source at low frequencies. This is attributed to ill-conditioning of the system resulting from a non-unique solution at zero frequency. 相似文献