Growth and biochemical responses of the offspring of mussels directly affected by the "Prestige" oil spill     

Peteiro  Laura G.; Filgueira  Ramon; Labarta  Uxio; Fernandez-Reiriz  Maria Jose 《ICES Journal of Marine Science》2008,65(4):509-513

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Vertical harmonic vibration of piled raft foundations in layered soils          下载免费PDF全文

C. L. Liu  Z. Y. Ai 《国际地质力学数值与分析法杂志》2017,41(17):1711-1723

This paper develops a method to analyze the piled raft foundation under vertical harmonic load. This method takes into account the interactions among the piles, soil, and raft. The responses of the piles and raft are formulated as a series of equations in a suitable way and that of layered soils is simulated with the use of the analytical layer‐element method. Then, according to the equilibrium and continuity conditions at the piles–soil–raft interface, solutions for the piled raft systems are obtained and further demonstrated to be correct through comparing with the existing results. Finally, some examples are given to investigate the influence of the raft, pile length‐diameter ratio, and layering on the response of the piled raft foundations. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Analysis of pile‐raft foundations under complex loads in layered soils     

Linlong Mu  Maosong Huang  Kenan Lian 《国际地质力学数值与分析法杂志》2014,38(3):256-280

Considering there is hardly any concerted effort to analyze the pile‐raft foundations under complex loads (combined with vertical loads, horizontal loads and moments), an analysis method is proposed in this paper to estimate the responses of pile‐raft foundations which are subjected to vertical loads, horizontal loads and moments in layered soils based on solutions for stresses and displacements in layered elastic half space. Pile to pile, pile to soil surface, soil surface to pile and soil surface to soil surface interactions are key ingredients for calculating the responses of pile‐raft foundations accurately. Those interactions are fully taken into account to estimate the responses of pile‐raft foundations subject to vertical loads, horizontal loads and moments in layered soils. The constraints of the raft on vertical movements, horizontal movements and rotations of the piles as well as the constraints of the raft on vertical movements and horizontal movements of the soils are considered to reflect the coupled effect on the raft. The method is verified through comparisons with the published methods and FEM. Then, the method is adopted to investigate the influence of soil stratigraphy on pile responses. The study shows that it is necessary to consider the soil non‐homogeneity when estimating the responses of pile‐raft foundations in layered soils, especially when estimating the horizontal responses of pile‐raft foundations. The horizontal loads and the moments have a significant impact on vertical responses of piles in pile‐raft foundations, while vertical loads have little influence on horizontal responses of piles in pile‐raft foundations in the cases of small deformations. The proposed method can provide a simple and useful tool for engineering design. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

超高层建筑桩筏基础的桩顶反力计算研究   总被引：2，自引：0，他引：2  

巢斯  赵锡宏  张保良  姜文辉  孔娟  肖俊华  袁聚云 《岩土力学》2011,32(4):1138-1142

根据上海高88层、筏板厚度为4 m的金茂大厦和高101层、筏板厚度为4.5 m的上海环球金融中心桩筏基础的实测沉降资料,论证超高层建筑的桩筏基础为弹性体。对以上两幢超高层建筑和正在建造中的高121层、筏板厚度为6 m的上海中心大厦的桩筏基础,采用偏心受压公式和高层建筑与地基基础共同作用理论方法(混合法)进行详细对比计算,论证按弹性体计算桩顶反力的合理性,阐明《建筑桩基技术规范》(JGJ 94–2008)的3.1.8条的正确性和合理性。期望能够改变过去按偏心受压公式计算桩顶反力的传统观念,提高设计水平。  相似文献   

Elastoplastic multiphase model for simulating the response of piled raft foundations subject to combined loadings     

G. Hassen  P. de Buhan 《国际地质力学数值与分析法杂志》2006,30(9):843-864

A multiphase model and corresponding computational time‐saving finite element code is proposed in this paper for predicting the settlements experienced by a piled raft foundation when subject to the combined action of vertical and lateral loadings. This model, which is formulated in the framework of an elastoplastic behaviour for the soil and the reinforcing piles as well, explicitly accounts for the shear and flexural behaviour of the latter. Starting from a simple analytical example where all the concepts attached to this model are clearly illustrated, the main stages leading to its finite element implementation are then presented. The numerical tool thus elaborated, is applied to the simulation of a pile‐reinforced strip foundation submitted to a horizontally applied seismic load in addition to a permanent vertical load. One of the key results of such a simulation in terms of design recommendation, lies in the conclusion that, while the shear and flexural contributions of the reinforcement play quite a negligible role in the case of a vertical load (as compared with their axial resistance), they remain absolutely essential for withstanding the seismic lateral loading. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

A simplified analysis method for piled raft and pile group foundations with batter piles     

Pastsakorn Kitiyodom  Tatsunori Matsumoto 《国际地质力学数值与分析法杂志》2002,26(13):1349-1369

A simplified method of numerical analysis has been developed to estimate the deformation and load distribution of piled raft foundations subjected to vertical, lateral, and moment loads, using a hybrid model in which the flexible raft is modelled as thin plates and the piles as elastic beams and the soil is treated as springs. Both the vertical and lateral resistances of the piles as well as the raft base are incorporated into the model. Pile–soil–pile, pile–soil–raft and raft–soil–raft interactions are taken into account based on Mindlin's solutions for both vertical and lateral forces. The validity of the proposed method is verified through comparisons with several existing methods for single piles, pile groups and piled rafts. Workable design charts are given for the estimation of the lateral displacement and the load distribution of piled rafts from the stiffnesses of the raft alone and the pile group alone. Additionally, parametric studies were carried out concerning batter pile foundations. It was found that the use of batter piles can efficiently improve the deformation characteristics of pile foundations subjected to lateral loads. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Optimised design of jet-grouted raft using response surface method     

《Computers and Geotechnics》2016

The use of jet grouting as a foundation supporting element has brought about the need to define the design strategies for jet-grouted raft (JGR) system which differs from the traditional raft design due to the effects of jet-grouted columns (JGCs). Paper tackles this important aspect by combining the previously defined design strategies on piled raft and JGC to achieve an optimised design of complete JGR system. Initially, a single JGC has been analysed by means of three dimensional finite element (3D FE) analysis accounting for the previously measured actual trial JGC’s geometrical variation with depth. The image processing technique allowing the complex 3D FE modelling of JGC system is utilised and the results are validated by the back-analysis of the well-known experimental results reported in the literature. In a parametric study, extension of the numerical analysis to the complete JGR system is accomplished by considering the mutual interaction between the foundation elements. The effects of design factors that are interlayer thickness, JGC spacing and lengths on the design responses of vertical stresses, bending moments, average and differential settlements are presented. Response Surface Method is utilised in the multi objective optimisation analysis to present the optimised design solution by accounting for the design constraints previously defined for the considered factors and the responses. The significance of design constraints and their relative influences on the optimised design of JGR are finally discussed.  相似文献   

Non-linear soil–structure interaction in disconnected piled raft foundations     

《Computers and Geotechnics》2015

Disconnected piled raft foundations are characterised by no structural connection between the upper raft and the underlying piles, mostly playing the role of settlement-reducers. The resulting raft–pile gap is usually filled with a granular interlayer, through which the loads from the superstructure are transferred to the piles.In this paper, the complex interaction mechanisms involving the foundational components (raft, piles and soil) are numerically investigated by means of 3D finite elements analyses, accounting for soil non-linearity. The main features of the soil–structure interaction mechanisms under purely vertical external loads are explored over a realistic range of raft–soil gaps for different pile configurations, in which the number of piles – i.e. their spacing – is varied. Special attention is also devoted to the structural response of the piles in terms of axial and bending internal stress resultants. In particular, while disconnection beneficially affects the structural pile response, increasing the raft–pile gap tends to reduce the overall settlement/stiffness efficiencies.The numerical results being presented are in substantial agreement with the outcomes from literature small-scale experiments and suggest a number of relevant theoretical inferences.  相似文献   

某岛筏式液压波浪发电装置系留系统动力学分析   总被引：2，自引：0，他引：2  

张大朋  朱克强  李园园  朱艳杰  严心宽  荆彪  陈凯 《海洋科学》2015,39(10):60-67

为研究某波浪发电装置系留设备的系泊性能,参考某岛筏式液压波浪发电项目规划和该系留系统的布局设计,利用OrcaFlex建立了系留系统简化模型。通过调节不同海况下的浪流参数,实现了对该系留系统的动力学分析,对比了不同工况下锚泊系统有效张力的变化,结合改变辅缆上端链与浮筏主体的连接位置,给出了该系留系统的优化设计方案。结果表明,不同系泊缆索上的系泊张力分布情况及风载荷对系留系统的影响很微弱。  相似文献   

梁板式高桩码头结构整体可靠度计算方法     

王禹迟  王元战  龙俞辰  高树奇 《海洋工程》2015,33(1):58-65

在环境条件和使用荷载作用下,高桩码头结构损伤和承载力降低是普遍存在的问题。在役梁板式高桩码头结构安全评估,是保证港口设施安全运行的必要措施。结构整体可靠度是结构安全评估的核心指标,但目前尚未建立结构整体可靠度计算的有效方法。基于非线性有限元数值模型,采用蒙特卡罗模拟技术确定了典型梁板式高桩码头结构整体极限承载力概率分布模型及其统计参数,研究了损伤位置、损伤程度和损伤数量等对极限承载力概率分布及其统计参数的影响,明确了无损结构整体极限承载力概率分布模型及其统计参数可用于损伤结构分析。将结构整体极限承载力作为结构抗力随机变量,采用一次二阶矩法计算结构的可靠指标,建立了一种在役梁板式高桩码头结构整体可靠度计算的有效方法。  相似文献