共查询到20条相似文献，搜索用时 31 毫秒
1.
V.Yu. Timofeev D.G. Ardyukov V.M. Solov'ev S.V. Shibaev A.F. Petrov P.Yu. Gornov N.V. Shestakov E.V. Boiko A.V. Timofeev 《Russian Geology and Geophysics》2012,53(4):376-391
The recent geodynamics of the Far East region of Russia is considered, where three large tectonic plates converge—Eurasian, North American, and Pacific, as well as several microplates—Okhotsk, Bering, and Amurian—have been hypothesized to exist. The available data on the position of the plate boundaries, the relative plate rotation poles, and the regional seismicity were analyzed, and parameters of plate motion models for northeastern Russia were determined in this study. The regional deep structure was investigated, using data obtained by different geophysical methods. The results of observations of the Magadan–Vrangel Island profile by deep seismic sounding (DSS), common-depth point (CDP) method, and correlation refraction method (CRM) are presented. 相似文献
2.
The paper considers the influence of a building wall system on the interaction between the soil and the foundation plate. A simplified semi-analytical finite element method gives an economical solution for large three-dimensional soil-structure interaction problems. The simplified method appears to be sufficiently accurate for engineering purposes. Numerical results presented show significant influence of building walls on the foundation-plate-soil interaction. 相似文献
3.
Plate anchors, such as suction embedded plate anchors and vertically driven plate anchors, offer economically attractive anchoring solutions for deep/ultra-deep water offshore developments. The rotation/keying processes of plate anchors will cause embedment losses, which lead to decreases of the uplift resistances of the anchors in normally consolidated soil. In the present paper, the keying processes of vertically installed strip and square plate anchors are simulated using the 3-D large deformation finite element method. The effects of loading eccentricity and pullout angle on the embedment loss during keying are investigated. Both the development of the uplift resistance and the soil flow mechanisms are presented. The numerical results show that the loading eccentricity e/B has a much larger effect on the embedment loss than the pullout angle does. The anchor shape has a minimal effect on the loss in anchor embedment. The shape factors (square/strip) are 1.05–1.09 for loss of embedment and 1.10–1.19 for capacity. 相似文献
4.
A new numerical tool is presented which models the two-dimensional contaminant transport through saturated porous media using a meshfree method called the radial point interpolation method (RPIM) with polynomial reproduction. In RPIM, an approximate solution is constructed entirely in terms of a set of nodes and no characterisation of the interrelationship of the nodes is needed. An advection-dispersion equation with sorption is considered to illustrate the applicability of the RPIM. The Galerkin weak form of the governing equation is formulated using two-dimensional meshfree shape functions constructed using thin plate spline radial basis functions. A computer program is developed for the implementation of the RPIM procedure. Three numerical examples are presented and the results are compared with those obtained from the analytical solution and finite element method. The experimental results are also used to validate the approach. The proposed RPIM has generated results with no oscillations and they are insensitive to Peclet constraints. 相似文献
5.
石窟薄层顶板破坏的早期潜在原因分析 总被引：5，自引：5，他引：0
为了探讨导致某石窟4号硐顶板破坏的最初潜在原因,根据石窟变形破坏规律及结构边界条件,采用粘弹性薄板理论,给出了广义开尔文模型下岩层的粘弹性变形、应力解析解。为了在任意一时刻给出全域应力、位移的分布状态,提出了一种解析解全域逐点搜索法,将全域划分细密网格,用所建立的解析解计算每小区中点的应力及网格点位移值。通过分析计算,给出了石窟顶板随时间变化的位移场、变形规律及顶板可能产生受拉破坏的变化规律,其中,有两处的受拉区分界线与现在的破坏裂缝线基本吻合,说明石窟成形初期,因内能释放而产生的受拉区及其边界分界线是后来真正破坏的早期潜在不稳定源。这一结论对保护和维护石窟稳定性具有实际参考意义。实例表明,所建立的模型及分析方法是正确和合理的,方法及结论均具有通用性。 相似文献
6.
A. P. S. Selvadurai 《国际地质力学数值与分析法杂志》1989,13(2):159-170
The problem of the axial loading of a rigid disk-shaped anchor plate embedded in an isotropic elastic medium of infinite extent is examined. At the boundary of the disk anchor plate the elastic medium contains a cracked region of finite extent. The presence of the cracked region decreases the elastic stiffness of the anchor plate. The mathematical formulation of the problem is developed, and a numerical scheme is presented which can be used to solve the resulting coupled integral equations. The numerical technique is used to evaluate the results, which illustrate the manner in which the elastic stiffness of the anchor plate is influenced by the extent of cracking. Similar results are developed for the flaw shearing mode stress intensity factor at the external boundary of the cracked region. 相似文献
7.
This paper discusses the use of a vibration-based technique for damage detection in metal and composite plate wrappings for
pier foundation repairs. The SLSE (Scanning Laser-Strain Energy) method relies on full-field laser modal scanning and strain
energy computation to establish damage locations within composite wrappings. Strain energy distribution relies on segmental
derivation of detected deflection shapes; hence, large numbers of spatial data points are required. By providing high spatial
data density, laser scanner complement nicely with the damage detection technique. Using an aluminum plate and a composite
plate, results from a baseline scan test is presented in this paper to demonstrate the show the high potential of this technique
for detecting damage in plates commonly used for structural repairs. 相似文献
8.
This paper is intended to give some information about how to build a model necessary for bending analysis of rectangular and circular plates resting on a two‐parameter elastic foundation, subjected to combined loading and permitting various types of boundary conditions. The formulation of the problem takes into account the shear deformation of the plate and the surrounding interaction effect outside the plate. The numerical model based on an 18‐node zero‐thickness isoparametric interface element interacting with a thick Reissner–Mindlin plate element with three degrees of freedom at each of the nine nodes, which enforce C0 continuity requirements for the displacements and rotations of the midsurface, is proposed. Stiffness matrices of a special interface element are superimposed on the global stiffness matrix to represent the stiffening elastic foundation under and beyond the plate. Some numerical examples are given to illustrate the advantages of the method presented. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
9.
基于Hoek-Brown破坏准则的浅埋条形锚板抗拔力上限分析 总被引：2，自引：0，他引：2
现有的锚板极限承载力研究大多是采用线性或非线性Mohr-Coulomb破坏准则在砂质地基中进行的,然而Mohr-Coulomb破坏准则并不适合分析岩质地基中的抗拔结构。采用Hoek-Brown破坏准则构建了一个曲线型的破坏机制,根据极限分析上限定理求出了条形锚板抗拔力的表达式。通过变分计算,得到了极限状态下条形锚板的抗拔力和岩体破裂面的上限解。为了证明所采用方法的有效性,当材料参数B =1时,采用与Mohr-Coulomb破坏准则等效的土体参数,计算了曲线型破坏机制下条形锚板的极限抗拔力,并与已有计算结果进行了比较。结果表明,采用曲线型破坏机制得到的锚板极限抗拔力与直线型多块体破坏机制的结果基本一致,证明了所采用的曲线形破坏机制是正确的。参数研究表明：在其他参数不变的情况下,锚板极限抗拔力和破坏面都随岩体参数B的增大而减小。 相似文献
10.
板块构造的启动时间和机制,一直是国内外地球科学界关注的焦点,有不少热点文章对此进行了讨论。它涉及的不仅是早期地球的构造机制问题,更关系到整个地球的演化历史、变化过程和演化规律,以及地球的未来。本文对国内外的研究状况、研究重点进行了简单述评,强调地球的"热状态和热演化"是构造机制演化的关键控制因素,提出大陆形成和岩石圈的演化与板块构造起源关联密切,是理解早期板块构造启动的重要研究内容。华北克拉通是代表性的古老大陆,本文对它的研究状况给出了介绍和评述。文章最后展望了"早期大陆与板块构造启动"这一重要科学问题的研究方向,并对相应的研究方法提出了评论和建议性意见。 相似文献
11.
压板载荷试验是目前被普遍采用且认为是最可靠的地基承载力确定方法,但其影响因素多诸如压板尺寸、埋置深度、地基土均匀性、沉降稳定标准等,尤其以压板尺寸对试验结果的影响最大。工程实践表明,利用压板试验确定的地基承载力特征值设计的基础,实测沉降与计算沉降之间的误差较大,在已有研究成果基础上,研究载荷试验尺寸效应及地基承载力确定方法：（1）综述目前地基承载力确定方面存在问题;（2）分析载荷试验的尺寸效应;（3）基于杨光华教授提出的非线性切线模量法,推导并给出了如何利用小压板载荷试验结果得到实际基础的荷载-沉降曲线的方法;（4）给出利用实际基础的p-s曲线确定地基承载力的方法,实现地基安全和沉降双控的目的;（5）由于压板试验只能反映浅层土,文中利用旁压试验确定深层土的地基承载力的方法。具体工程实例结果表明,基于利用小压板获得的参数计算的沉降值更符合实际;研究通过小压板原位测试方法获取沉降计算的岩土体统参数方法,不仅能够提高沉降计算精度,还可促进基础设计理论的发展和设计水平的提高。 相似文献
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14.
John A. Hildebrand 《Tectonophysics》1989,170(3-4):279-287
Paleomagnetism of eastern Nazca plate seamounts defines Nazca and Farallon absolute plate motion during Cenozoic times. Magnetic and bathymetric surveys are presented for two eastern Nazca plate seamounts in the Chile Basin and they are used to calculate paleomagnetic poles with uniform and nonuniform magnetic modeling. The paleopole for Piquero-2 seamount is coincident with the earth's pole, suggesting a young seamount. The paleopole for Piquero-1 seamount indicates that the Nazca plate moved 23° northward during 0–50 ma. This is 13° more latitudinal motion than predicted by a Pacific hotspot reference frame and 20 ° more motion than predicted by DSDP sediment and basalt paleomagnetism. 相似文献
15.
Keisuke Ito 《Tectonophysics》1979,57(1):85-94
A simple, rheological model is presented for plate motions to explain episodic volcanism and tectonism. A lithospheric plate is modelled by a gliding block and the basal edge of the sinking plate is modelled by a stick-slip-like fault system. The friction force is assumed to have a maximum at a critical sliding velocity. When the sliding velocity at the basalt edge exceeds the critical velocity, the basal edge system becomes unstable and the plate accelerates. Conditions that the model system has a periodic solution are obtained and parameters of the system are evaluated from rheological properties of the mantle and configurations of the plate. Results suggest that a plate moves nearly steadily over a long period of time but it accelerates sharply during a very short period of time. The accelerating period is considered to correspond to the episodes of active volcanism and tectonism. 相似文献
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17.
Tectonic progradation and plate tectonic evolution of the Alps 总被引：2，自引：0，他引：2
W. Frisch 《Tectonophysics》1979,60(3-4):121-139
Rifting and spreading, trench formation, flysch deposition, subduction and nappe formation prograde from internal to external parts of the Alpine orogen. The progradation is a characteristic feature of the evolution of the Alps. A plate tectonics model based on this cognition is presented and an attempt is made to integrate the plate movements of the Alpine region during the Mesozoic and Cenozoic into the plate pattern of the Western Mediterranean.
Important events in the evolution of the Alps are the successive opening and closing of the Piedmont (South Penninic) and Valais (North Penninic) oceans, and the two continental collisions related to this. The southward drift of the Briançonian plate in the Cretaceous closes the Piedmont and opens the Valais ocean. The evolution of these oceans is related to the plate movements in the North Atlantic. The second continental collision is followed by the formation of an exogeosyncline, the molasse foredeep.
Prograding orogens like the Alps are most likely to evolve in an originally continental environment by rifting. Retrograding orogens, however, indicate an originally oceanic environment with well-developed magmatic arcs and back-arc basins. 相似文献
18.
为了建立一种参数有明确物理意义的土-水特征曲线拟合方法,基于分形理论,给出了一种直接通过土-水特征曲线实测数据求解分维数的计算方法,建议了一种土-水特征曲线拟合分析的分形模型。为验证所建议拟合方法的合理性,采用液压千斤顶制作了7个不同干密度黏性土试样,利用压力板仪测量了土-水特征曲线。基于土-水特征曲线实测值计算了分维数,在此基础之上对土-水特征曲线实测数据进行分析拟合。结果表明：分维数计算及拟合分析时,7个试样相关系数都集中在0.97～0.99之间,从而证明了土-水特征曲线具有良好的分形特性,建议的拟合方法效果较好。此外,研究发现,分维数、进气值随干密度几乎呈线性增加,据此建议了一种不同压实度下的土-水特征曲线预测方法,其预测结果与实测值吻合较好。 相似文献
19.
G. Russo 《国际地质力学数值与分析法杂志》1998,22(6):477-493
An approximate numerical method for the analysis of piled raft foundations is presented. The raft is modelled as a thin plate and the piles as interacting non-linear springs. Both the raft and the piles are interacting with the soil which is modelled as an elastic layer. Two sources of non-linearity are accounted for: (i) the unilateral contact at the raft–soil interface and (ii) the non-linear load–settlement relationship of the piles. Both theoretical solutions and experimental results are used to verify that, despite the approximations involved, the proposed method of analysis can provide satisfactory solutions in both linear and non-linear range. © 1998 John Wiley & Sons, Ltd. 相似文献
20.
WangYuanhan GongWenhui 《中国地质大学学报(英文版)》2004,15(4):401-408
The vibration analysis of a plate on an elastic foundation is an important problem in engineering. It is the interaction of a plate with the three-dimensional half space and the plate is usually loaded from both the upper and lower surfaces. The contact pressure from the soil can not be predefined. According to Lambs solution for a single oscillating force acting on a point on the surface of an elastic half space, and the relevant approximation formulae, a relation between the local pressure and the deflection of the plate has been proposed. Based on this analysis, the reaction of the soil can be represented as the deformation of the plate. Therefore, the plate can be separated from the soil and only needs to be divided by a number of elements in the analysis. The following procedure is the same as the standard finite element method. This is a semi-analytical and semi-numerical method. It has been applied to the dynamic analysis of circular or rectangular plates on the elastic half space, at low or high frequency vibration, and on rigid, soft or flexible foundations. The results show that this method is versatile and highly accurate. 相似文献