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1.
This paper presents an effective analysis procedure for the dynamic soil-structure interaction problem considering not only the sliding and separation phenomena but also the non-linear behaviour of soil by the finite element method. Soil is assumed to be an elasto-plastic material and the contact surface between the soil and structure is modelled by the joint element. The load transfer method is adopted to carry out dynamic non-linear response analysis. The method is applied to the response analysis of a nuclear reactor building resting on the ground surface. The effects of non-linear behaviour of soil on the safety against sliding of the structure are examined. The numerical computations reveal the following results: that the non-linear behaviour of soil reduces the response of the system and the magnitude of sliding of the structure, and that the safety against sliding obtained by the proposed method is higher than the safety obtained by classical methods. This implies the possibility of a more rational and economical design of large structures; it can be said that the proposed method provides useful information for the stability analysis of important and large structures. 相似文献
2.
强地震动作用下地铁结构与土脱开滑移的研究 总被引：4，自引：0，他引：4
刘如山 《地震工程与工程振动》2004,24(6):136-141
应用反应位移法,有限元反应位移法和有限元动力分析方法,以兵库县南部地震的Port-Island观测波形作为地震动输入,对某给定地质条件下的浅埋箱型地铁结构进行了不考虑结构与土脱开滑移和考虑结构与土脱开滑移的两种情况的计算,通过计算可以了解到一般箱型结构与上脱开,滑移的位置和范围,计算结果表明,抗震设计时,在强地震作用下,结构与土的脱开,滑移作用考虑与否,对结构变形和断面力计算值的影响很大。 相似文献
3.
均匀土-桩基-结构相互作用体系的计算分析 总被引：14，自引：4，他引：14
本文以结构－地基动力相互作用振动台模型试验为基础，结合通用有限元软件ANSYS，对均匀土－桩基－结构动力相互作用体系进行了三维有限元分析。计算中土体采用等效线性模型，利用面－面接触单元考虑土体与结构交界面的状态非线性，计算与试验得出的规律基本一致。桩基与土体间发生了脱开再闭合和滑移现象。桩身应变幅值分布呈桩顶大、桩尖小的倒三角分布，角桩的应变幅值较大，边排中桩和中桩的应变幅值较小。桩土接触压力幅值呈桩顶小、桩尖大的三角形分布。在沿振动方向的三排桩中，边排桩的滑移比中排桩的滑移量大。通过计算分析与试验的对照研究，验证了采用的计算模型与分析方法的合理性，为结构－地基相互作用的进一步研究奠定了基础。 相似文献
4.
土体-结构界面接触对地下结构动力反应的影响 总被引：3，自引：0，他引：3
迄今为止,关于土体与结构交界面的接触效应对地下结构地震反应的影响尚未引起研究者们的重视,成果鲜有报道。本文基于接触面对法和非线性有限元波动分析方法,建立了考虑土体与结构界面接触效应的地下结构非线性地震反应分析模型和计算方法,并利用大型有限元软件ANSYS进行了求解。分析结果表明：土体与结构界面的接触效应对地下结构地震反应有明显影响,可能增大地下结构节点的峰值加速度、峰值位移和峰值应力反应;随着接触摩擦系数的增大,接触点的相对滑移逐渐减小,而接触应力的变化则无明显规律。 相似文献
5.
A two-dimensional (2D) finite element analytical model is developed to analyze the seismic response of rigid highway bridge abutments, retaining and founded on dry sand. A well verified finite element code named FLEX is used for this purpose. The proposed model has the following characteristics: (1) The soil (dry sand in this study) is modeled by a 2D finite element grid; (2) The bridge abutment is molded as a rigid substructure; (3) The strength and deformation of the soil are modeled using the viscous cap constitutive model. This model consists of a failure surface and hardening cap together with an associated flow rule. The cap surface is activated for the soil under the wall to represent compaction during wall rocking. In addition, viscoelastic behavior is provided for representing the hysteretic-like damping of soil during dynamic loading; (4) Interface elements are used between the wall and the soil (at the backface of the wall and under its base) to allow for sliding and for debonding/recontact behavior; (5) The finite element grid is truncated by using an absorbing boundary approximation. Using this boundary at both sides of the grid simulates the horizontal radiation of energy scattered from the wall and the excavation. Shear beams are placed adjacent to the lateral boundaries from each side which give the far-field ground motion, for comparison with those computed adjacent to the boundaries. The analytical model is verified comparing predictions to results from dynamic centrifuge tests, with satisfactory agreement. The proposed model is used to study the dynamic response of an 8.0 m high and 3.0 m wide rigid bridge abutment (proportioned using the traditional approach to design) for different sinusoidal and earthquake acceleration input motions. The results from the analysis show that outward tilting of rigid bridge abutments is the dominant mode of response during dynamic shaking and that these abutments end up with a permanent outward tilt at the end of shaking. The results from all the analyzed cases of the 8.0 m high gravity retaining wall together with those from the analysis of the tilting wall centrifuge tests are discussed and used for proposing a practical method for evaluating the seismic response of rigid abutments during earthquakes. 相似文献
6.
均匀土-箱基-结构相互作用体系的计算分析 总被引：4，自引：0，他引：4
采用通用有限元程序ANSYS，针对捱动台试验中的均匀土-箱基-结构试验进行了三维有限元分析，计算中土体的本构模型采用等效线性模型，利用面-面接触单元考虑土体与基础交界面的状态非线性。计算表明，基础底面和土体发生滑移，基础侧面和土体之间发生了滑移和脱离，上部结构柱顶加速度反应主要由基础转动引起的摆动分量组成，通过与试验结果的对照研究，二者得出的规律基本一致，验证了采用的计算模型与分析方法的合理性，为进一步计算研究和实际工程应用奠定了基础。 相似文献
7.
人工神经元网络在公路工程震害预测方面的应用 总被引：2，自引：0，他引：2
本文采用人工神经网络理论，对城市公路网络中的单元路段和桥梁的震害预测进行了探讨。在闪人研究的基础上，提出了解决这一非确定性问题的一个有效的方法。对于深入研究生命线工程系统震害的规律具有普遍贩意义，从而使我们有可能避免地震造成的破坏和最大限度地减小损失，为抗震减灾提供决策依据。 相似文献
8.
关于埋深对地下结构地震反应的影响的研究对象多见于地下隧道,对地铁车站地震反应受埋深影响变化规律缺乏深入研究。本文基于ANSYS有限元软件,采用改进的简化方法建立三种不同埋深的地铁车站结构有限元模型,以两种基岩波的水平向和竖向地震动作为激励,求解各模型中地铁车站结构重要部位的地震反应。分析不同埋深时地铁车站结构惯性作用、侧面土体和上部土体三个因素对地铁车站地震反应的影响情况。分析结果表明:在双向地震作用下,地铁车站侧壁弯矩、剪力、轴力和中柱轴力随埋深的增加而增加,中柱剪力和弯矩随埋深增加而减少。埋深越深,侧面土体对地铁车站地震反应影响越大;上部土体使中柱轴力不断增加;结构自身的惯性作用对其地震反应的贡献逐渐减小。 相似文献
9.
Influence factors on the ground surface rupture zone induced by buried normal fault dislocation* 
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下载免费PDF全文 The seismic disaster presents a zonal distribution along the fault strike. In this paper, rupture zone of ground surface soil caused by the uniform dislocation, inclined dislocation and warped dislocation of buried normal fault are studied by constituting a three-dimensional finite element model in Automatic Dynamic Incremental Nonlinear Analysis (ADINA). According to the critical value of surface rupture, the variational features and influencing factors of width and starting position of the “avoiding zone” in engineering construction are analyzed by using 96 model calculations. The main results are as follows: (1) Since the rupture zone of the ground surface soil from the point of mechanics is different from the “avoidance zone” from the point of engineering safety, the equivalent plastic strain and the total displacement ratio should be considered to evaluate the effect of the seismic ground movement on buildings. (2) During fault dislocation, plastic failure firstly occurred on the ground surface soil of the footwall side, and then the larger deformation gradually moved to the side of the hanging wall of the fault with the increase of fault displacement. (3) When the vertical displacement of buried fault reaches 3 m, the width of “avoiding zone” in engineering construction varies within the range of 10–90 m, which is most affected by the thickness of overlying soil and the dip angle of the fault. 相似文献
10.
土-桩-框架结构非线性相互作用的精细数值模型及其验证 总被引：1，自引：0，他引：1
利用有限元软件ABAQUS,建立了土-桩-框架结构非线性相互作用（SSI）的二维精细有限元模型,分别采用记忆型粘塑性嵌套面模型和损伤塑性模型模拟土体和混凝土材料,采用梁单元和rebar单元模拟RC桩基及其内部纵筋,采用接触面对法模拟桩土接触效应,取得了良好的计算效果。将自由场、框架、土-桩-框架结构模型的分析结果和其它成熟的计算软件进行对比,验证了数值模型的有效性。分析发现：桩基外侧靠近承台处的土体的非线性反应很强烈,而桩基内部土体的非线性反应较小,很大程度上只是跟随群桩一起运动。由于桩土动力接触,桩顶的加速度反应可能超出上部结构,并且桩顶的加速度时程曲线上有非常明显的＂针＂状突变。随着地震动强度的增加,上部框架逐渐表现出单自由度体系的动力特征,加速度反应谱有从多个波峰退化为单一波峰的趋势。 相似文献
11.
R. Kourkoulis I. AnastasopoulosF. Gelagoti G. Gazetas 《Soil Dynamics and Earthquake Engineering》2010
This paper studies the combined effects of earthquake-triggered landslides and ground shaking on foundation−structure systems founded near slope crests. Plane-strain nonlinear finite element dynamic analyses are performed. The soil constitutive model is calibrated against published data to simulate the (post-peak) softening behavior of soil during a seismic event and under the action of gravitational forces. The plastic shear zones and the yield accelerations obtained from our dynamic analyses are shown to be consistent with the slip surfaces and the seismic coefficients obtained by classical pseudostatic limiting equilibrium and limit analysis methods. The foundation and frame columns and beams are modeled as flexural beam elements, while the possibility of sliding and detachment (separation) between the foundation and the underlying soil is considered through the use of special frictional gap elements. The effects of foundation type (isolated footings versus a rigid raft) on the position of the sliding surface, on the foundation total and differential displacements, and on the distress of the foundation slab and superstructure columns, are explored parametrically. It is shown that a frame structure founded on a properly designed raft could survive the combined effects of slope failure and ground shaking, even if the latter is the result of a strong base excitation amplified by the soil layer and slope topography. 相似文献
12.
Kemal Hacıefendioğlu Emre Alpaslan 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(2):415-427
This paper presents the dynamic response analysis of industrial masonry chimney subjected to artificially generated surface blast induced ground shock by using a three-dimensional finite element model. The effects of surface blast-induced ground shocks on nearby structures depend on the distance between the explosion centre and the structure, and charge weight. Blast-induced ground motions can be represented by power spectral density function and applied to each support point of the 3D finite element model of the industrial masonry system. In this study, a parametric study is mainly conducted to estimate the effect of the blast-induced ground motions on the nonlinear response of a chimney type masonry structure. Therefore, the analysis was carried out for different values of the charge weights and distances from the charge center. The initial crack and propagation of the crack pattern at the base of the chimney were evaluated. Moreover, the maximum stresses and displacements through the height of the chimney were investigated. The results of the study underline that blast-induced ground motions effects should be considered to perform the non-linear dynamic analysis of masonry type chimney structures more accurately. 相似文献
13.
A three-dimensional backfill–structure–soil/foundation interaction phenomenon is simulated using the finite element method in order to analyze the dynamic behavior of cantilever retaining wall subjected to different ground motions. Effects of both earthquake frequency content and soil–structure interaction are evaluated by using five different seismic motions and six different soil types. The study mainly consists of three parts. In the first part, following a brief review of the problem, the finite element model with viscous boundary is proposed under fixed-base condition. In the second part, analytical formulations are presented by using modal analysis technique to provide the finite element model verification, and reasonable agreement is found between numerical and analytical results. Finally, the method is extended to further investigate parametrically the effects of not only earthquake frequency content but also soil/foundation interaction, and nonlinear time history analyzes are carried out. By means of changing the soil properties, some comparisons are made on lateral displacements and stress responses under different ground motions. It is concluded that the dynamic response of the cantilever wall is highly sensitive to frequency characteristics of the earthquake record and soil–structure interaction. 相似文献
14.
地下输液管道动力反应分析 总被引：9，自引：3，他引：6
本文利用有限元方法,考虑介质、埋设管线及土壤的相互作用,进行了埋地管线动特性和地震动响应研究,得出了土特性、管内液体流动对系统固有频率及动力响应影响的若干初步结论。 相似文献
15.
考虑土-结构相互作用的高层建筑抗震分析 总被引：17，自引：0，他引：17
本文采用通用有限元程序ANSYS,针对上海地区一例土-箱基-高层建筑结构进行了三维有限元分析,计算中土体的本构模型采用等效线性模型,利用粘一弹性人工边界作为土体的侧向边界,并研究了土体边界位置、土性、基础埋深、基础形式以及上部结构刚度等参数对动力相互作用体系动力特性及地震反应的影响。 相似文献
16.
基于室内试验获取黄土滑坡的静力和动力力学强度参数,建立低角度黄土滑坡破坏大型物理模拟试验模型,结合FLAC3D有限差分软件,分析黄土滑坡的动力响应规律和宏观破坏特性,阐明在地震作用下黄土滑坡的失稳演化规律,揭示黄土滑坡滑体运动迁移路径。结果表明：低角度黄土-泥岩滑坡在地震荷载作用下地震波水平方向和垂直方向均出现明显的放大效应;在黄土层内部,随着斜坡高度增加,坡肩和斜坡后缘加速度放大效应较为明显,对比坡脚、坡腰和坡肩处剖面上加速度放大系数,下伏泥岩对地震波产生一定的放大效应。松弛拉张裂隙,土体强度降低,接触面和坡肩、斜坡后缘处的拉张裂缝形成弧形滑移面,上覆黄土层由内向外依次连带下滑,坡肩处土体的下滑力和地震力促使坡腰土体大面积长距离滑动,最大滑动涉及范围长达200 m左右,土体下滑至坡脚发生堆积并产生隆起。数值模拟结果和振动台试验结果在动力响应和宏观变形破坏特征均呈现较高的吻合度。 相似文献
17.
A general substructure method for analysis of response of structures to earthquake ground motion, including the effects of structure-soil interaction, is presented. The method is applicable to complex structures idealized as finite element systems and the soil region treated as either a continuum, for example as a viscoelastic halfspace, or idealized as a finite element system. The halfspace idealization permits reliable analysis for sites where essentially similar soils extend to large depths and there is no rigid boundary such as soil-rock interface. For sites where layers of soft soil are underlain by rock at shallow depth, finite element idealization of the soil region is appropriate; in this case, the direct and substructure methods would lead to equivalent results but the latter provides the better alternative. Treating the free field motion directly as the earthquake input in the substructure method eliminates the deconvolution calculations and the related assumption—regarding type and direction of earthquake waves—required in the direct method. Spatial variations in the input motion along the structure-soil interface of embedded structures or along the base of long surface supported structures are included in the formulation. The substructure method is computationally efficient because the two substructures—the structure and the soil region—are analysed separately; and, more important, it permits taking advantage of the important feature that response to earthquake ground motion is essentially contained in the lower few natural modes of vibration of the structure on fixed base. 相似文献
18.
The response of an earth dam to seismic loading is studied through displacement-based analyses and finite element, effective stress dynamic analyses. Displacement-based analyses are carried out using both empirical relationships and the decoupled approach in which the deformable response of the soil is accounted for through ground response analyses, and the resulting accelerograms are used in the sliding block analysis. The FE analyses are carried out using a constitutive model capable to reproduce soil non-linearity, calibrated against laboratory measurements of the stiffness at small strains. The influence of the assumed input motion and bedrock depth on the seismic response of the dam is also studied. 相似文献
19.
The dynamic response of a seismic soil–pile–structure interaction (SSPSI) system is investigated in this paper by conducting nonlinear 3D finite element numerical simulations. Nonlinear behaviors such as non-reflecting boundary condition and soil–pile–structure interaction modeled by the penalty method have been taken into account. An equivalent linear model developed from the ground response analysis and the modified Drucker–Prager model are separately used for soil ground. A comparison of the two models shows that the equivalent linear soil model results in an underestimated acceleration response of the structure under this ground shaking and the soil behavior should be considered as a fully-nonlinear constitutive model in the design process of the SSPSI system. It was also observed that the dynamic response of the system is greatly affected by the nonlinearity of soil–pile interface and is not sensitive to the dilation angle of the soil. Furthermore, the effect of the presence of pile foundations on SSPSI response is also analyzed and discussed. 相似文献
20.
在地下结构抗震设计简化分析方法中,强制反应位移法将土层变形施加在有限元模型侧边界模拟地震作用,反应加速度法将土层加速度施加到整个有限元模型上模拟地震作用,此外还有仅将土层加速度施加到土层模型上模拟地震作用的方法。上述方法均规避了反应位移法中关于弹簧刚度的取值问题,提高了计算效率。本文以1个双跨箱形结构为例,用动力时程分析的计算结果作为校核,分析了强制反应位移法、反应加速度法和仅将土层加速度施加到土体中的简化分析方法在不同侧边距条件下的计算精度,再结合常用的反应位移法,对比分析了4种简化分析方法的误差。分析结果表明:使用强制反应位移法时,侧边距取为1倍结构宽度导致的误差最小,反应加速度法和仅在土体施加加速度的简化方法对侧边距取值不敏感,反应位移法在角点造成的误差最大。 相似文献