共查询到20条相似文献，搜索用时 132 毫秒
1.
粘弹性半空间内膨胀引起的地表垂直位移和重力变化 总被引：7，自引：0，他引：7
研究了粘弹性空间内膨胀（Ｍｏｇｉ模型）引起的地表垂直位移和重力变化，推导了Ｍａｘｗｅｌｌ半空间模型的解析计算公式。数值结果表明，地表垂直位移，重力变化以及重力变化与地表垂直位移之比受介质流变特性的影响很大，因此，在解释和模拟火山区，地壳隆地区，地热场等长期地表形变和重力观测时需考虑介质的流变特性影响。 相似文献
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任意震源力作用下多层粘弹性半无限地基平面问题的解析解 总被引：2，自引：0，他引：2
本文利用Ｆｏｕｒｉｅｒ变换及矩阵传递技术，导出了在任意震源力作用下多层粘弹性半无限地基平面问题的一般解析表达式。本文的方法概念清晰、公式简便实用。文中给出了计算实例，所得结果与现有文献的数值计算结果一致。 相似文献
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饱和土半空间中地下圆形衬砌洞室对平面SV波的散射 总被引：2，自引：0，他引：2
在Biot饱和多孔介质动力学理论的基础上,利用Fourier-Bessel级数展开法,通过对舍有衬砌洞室的局部场地进行波场分析,得到饱和土半空间中圆柱形衬砌洞室对平面SV波的散射问题的解析解。经验证,本文得到的解可以退化为半空间单相介质的情况。通过与已有的单相弹性介质半空间中圆柱形衬砌洞室对平面SV波散射问题的解析解的对比,验证了此解的正确性。在解析解的基础上,数值计算给出洞口动应力集中放大系数,分析了入射频率和孔洞埋深对柱面上的应力集中因子的影响。 相似文献
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本文在空间上采用有限元法。在时域上采用离散的方法。建立了用扩阶随机有限元方法求解含随机参数粘弹性问题的计算模型，并给出了算例。结果表明，本文解和Monte-Carlo模拟解吻合。 相似文献
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规则的沉积谷地对地震波散射问题解析解的研究是地球物理学、地震学与地震工程学等学科领域重要的研究课题之一.Trifunac最先利用波函数的Fourier-Bessel级数展开在极坐标系下给出了半圆形沉积谷地对平面SH波散射问题的精确解析解.其后,Wong和Trifunac利用波函数的Mathieu级数展开在椭圆坐标系下给出了半椭圆形沉积谷地对平面SH波散射问题的解析解. 相似文献
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本文首先从一般大地电磁(Magnetotelluric,MT)各向异性介质的二阶偏微分方程组出发,通过简化各向异性介质的电导率张量,获得剖面各向异性及平面各向异性介质情形下求解MT响应的二阶偏微分方程组.然后在对角各向异性MT响应解析解基础上,通过电导率的变换得到剖面各向异性及平面各向异性介质的解析解.其次,以各向同性介质为例,讨论了解析解计算过程中积分限与积分步长的选取对计算精度的影响.最后计算了两种剖面各向异性及平面各向异性介质模型的MT响应,并对各向异性介质模型MT响应解析解的一些应用做了讨论. 相似文献
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打桩引起的地面振动的研究 总被引：1，自引：0，他引：1
为了对打桩引起的地面振动进行研究,应用一维应力波理论建立了粘弹性成层土中等截面弹性桩的力学模型,得到了桩中任意一点处位移的半解析解。利用桩与土的相互作用将桩对土的作用力简化到各土层面上。在复阻尼理论和纳维方程的基础上,利用分层法得到了任意荷载作用下土的位移、速度和加速度的解。从而得到了打桩引起的地面振动的衰减特性。通过实测结果和计算结果的比较说明了该方法的可行性。 相似文献
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B. Reynolds 《地球表面变化过程与地形》1986,11(2):217-221
The individual outputs of several elements in solution, suspended solids and bedload were estimated for a stream draining a small upland catchment in mid-Wales. The data indicate the overall importance of transport in solution, although the solid phase can make a significant contribution to the export of potassium, iron and silicon from the site. 相似文献
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Most of the finite element analyses of reinforced concrete structures are restricted to two‐dimensional elements. Three‐dimensional solid elements have rarely been used although nearly all reinforced concrete structures are under a triaxial stress state. In this work, a three‐dimensional solid element based on a smeared fixed crack model that has been used in the past mainly for monotonic static loading analysis is extended to cater for dynamic analysis. The only material parameter that needs to be input for this model is the uniaxial compressive strength of concrete. Steel bars are modelled as uniaxial elements and an embedded formulation allows them to have any orientation inside the concrete elements. The proposed strategy for loading or unloading renders a numerical procedure which is stable and efficient. The whole process is applied to two RC frames and compared against existing experiments in the literature. Results show that the proposed approach may adequately be used to predict the dynamic response of a structure. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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为了提高木结构抗震性能分析的精度,采用多尺度建模分析方法对木结构进行抗震分析。利用多点约束方法分别将榫卯节点和梁柱构件设定为关键区域和非关键区域。采用多尺度的建模思想,对关键区域采用实体单元进行精细尺度建模,而非关键区域则采用梁单元进行普通尺度建模,再通过不同尺度实现宏观结构模型和局部微观模型的相互协调,比较不同尺度下的实体单元和梁单元建模在抗震中的性能。实验结果表明,多尺度的有限元数值分析能够模拟木结构的整体动力响应和精确分析边界条件。通过多尺度、大范围的分级建模能够构建局部和全局的抗震性能分析的过程,精度较高,可提升抗震分析的效率。 相似文献
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S. S. Kevorkyants 《Izvestiya Physics of the Solid Earth》2012,48(11-12):798-805
The system of Biot vector equations in the frequency space includes two elliptic-type vector partial differential equations with unknown displacement vectors in the solid and liquid phases. Considering the Biot equations, alongside with Pride??s equations, the key approaches to the theoretical study of the elastic waves in the two-phase fluid-saturated media, the author suggests an analytical solution for the inhomogeneous Biot equations in the frequency space, which is reduced to finding its fundamental solution (Green??s function). The solution of this problem consists of solutions for two systems of Biot equations. In the first system, only the first equation is inhomogeneous, while in the second system, only the second equation is inhomogeneous and, as it is shown, its right-hand side is exclusively a potential function. The fundamental solution of the full system of inhomogeneous Biot equations (in which both equations are inhomogeneous) is represented in the form of Green??s matrix-tensor, for the scalar elements of which the analytical relations are presented. The obtained formulas describing the elastic displacements of both the solid and liquid phases reflect three wave types, namely, compressional waves of the first and the second kind (the fast and the slow waves, respectively) and shear waves. Similar terms (those describing the same type of the elastic waves in the solid and liquid phases) in the expressions for Green??s functions are linked with each other through the coefficient that links the components of the displacement vectors of the solid and liquid phases corresponding to the given wave type. 相似文献
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A general solution of Biot's field equations governing small motions of a porous solid saturated by viscous liquid is employed to study the reflection and refraction at the interface between an elastic solid and a liquid-saturated porous solid. The incident wave is assumed to be plane and homogeneous, propagating through the isotropic elastic solid. The poroelastic solid is considered to be a dissipative one. Amplitude and energy ratios are computed numerically for a particular model. With first-order corrections for the porosity of solid and viscosity of liquid, the limiting cases of low and high frequencies are computed. 相似文献
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J. A. S. C. Jayasinghe M. Hori M. R. Riaz M. L. L. Wijerathne T. Ichimura 《地震工程与工程振动(英文版)》2017,16(2):297-309
In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. The proposed method is rigorous and efficient compared to a typical conversion method which merely computes surface integration of solid element nodal stresses to obtain cross-sectional forces. The meta-modeling theory ensures the rigorousness of proposed method by defining a proper distance between beam element and solid element solutions in a function space of continuum mechanics. Results of numerical verification test that is conducted with a simple cantilever beam are used to find the proper distance function for this conversion. Time history analysis of the main tunnel structure of a real ramp tunnel is considered as a numerical example for the proposed conversion method. It is shown that cross-sectional forces are readily computed for solid element solution of the main tunnel structure when it is converted to a beam element solution using the proposed method. Further, envelopes of resultant forces which are of primary importance for the purpose of design, are developed for a given ground motion at the end. 相似文献
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A numerical algorithm for predicting the migration of multiple subsurface pollutants has been developed accounting for dispersion, convection, soluble complexation and solid phase accumulations (sorption). The basis of the model is a finite element solution of the mass transport equation. The essence of the algorithm is the treatment of the sorption terms as implicit functions of the total soluble concentrations facilitating a general and modularized treatment of solution phase and solid phase chemistry. Examples are presented illustrating the effects of soluble complexation and competitive sorption on the transport of multicomponent solutions. 相似文献
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Gravity anomalies always include the total effects (combination of the structures which have different densities and depths) of the study area and beyond. And the well-known non-uniqueness of potential field modelling may lead to very different interpretation results.The finite element method (FEM), which has been used in potential field interpretation for decades, makes complex problems to be solved easily and accurately. The first step of FEM is to identify the elements and then to decide on the boundary of the solution space. In this step, the solution space is divided into elements. After determination of the geometrical structure of the solution space, the most suitable elements should be chosen for this geometrical structure. The agreement between the geometry and the elements is quite important for the convergence to the best possible solution.In this work, the methods of trend analysis, filtering, analytical continuation and FEM were applied to a theoretical model and to gravity data from western Turkey to produce the regional and the residual anomalies. The results were compared and it was found that the FEM produced more accurate results than other methods did. 相似文献
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A nonlinear, slip-joint element for analyzing the effect of discontinuities on a concrete, arch dam's seismic response is developed. The joint element has been incorporated into a finite-element-based, solution for predicting dynamic structural response. This joint model, plus the numerical procedure incorporated into the incremental solution, models inter-element impact across a joint when adjacent, structural elements separate and later collide. Collision is incorporated into the incremental analysis by calculating the exchange of momentum and energy with the equations describing eccentric, rigid-body impact. Joint material's force-deflection relations are multi-linear with hysteresis. Coulomb friction is also modeled. The joint element and numerical procedure have been tested with two models. The first is a segmented arch of seven, straight beam elements connected to one another. The arch dam has been experimentally tested. Analytical results are compared with experimental results from the sealed model. Second is a rectangular plate model subject to lateral base accelerations. One horizontal edge is fixed and the opposite edge is free. The vertical edges may be fixed or connected to the base by joint elements. 相似文献