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101.
102.
目前计算碎石桩处理软土地基临界填筑高度的方法并不完善,没有考虑软基经碎石桩处理后复合地基强度的增加和地基排水固结能力的提高,基于此,依据固结理论,引入碎石桩复合地基固结计算的简化方法,修正按变形控制的临界填筑高度计算公式;并结合四川省遂-资高速公路软基变形监测数据,得出软基厚度在6.5~11.0 m范围内,观测所得的临界填筑高度为4.5~6.5 m,该观测值与修正公式计算值差异性不显著,证实所推导的解析式是切实可行的;在此基础上,初步探讨影响路堤临界填筑高度变化的因素,得出软基厚度、桩间距对其影响较为明显。 相似文献
103.
The construction of large offshore wind turbines in seismic active regions has great demand on the design of foundations. The occurrence of soil liquefaction under seismic motion will affect the stability of the foundations and consequently the operation of the turbines. In this study, a group of earthquake centrifuge tests was performed on wind turbine models with gravity and monopile foundations, respectively, to exam their seismic response. It was found that the seismic behavior of models was quite different in the dry or saturated conditions. Each type of foundation exhibited distinct response to the earthquake loading, especially in the offshore environment. In the supplementary tests, several remediation methods were evaluated in order to mitigate the relatively large lateral displacement of pile foundation (by fixed-end pile and multi-pile foundation) and excessive settlement of gravity foundation (by densification, stone column, and cementation techniques). 相似文献
104.
Smoothed particle hydrodynamics (SPH) is a meshfree, Lagrangian particle method which has advantages in handling solids with extremely large deformation. Like any other numerical methods, cares must be taken to ensure its desirable accuracy and stability through considering several correction techniques in calculation. The selection of values for parameters in those correction approaches is a key step in SPH simulation, which is always difficult for new beginners to deal well with effectively. This paper examines the common inconsistency and instability problems in SPH method and studies its computational efficiency when applied to hydrodynamics problems with material strength like soil column collapse. We analyzed in detail how the correction techniques mitigate these inconsistency and instability problems. Also, the numerical testing results associate with different values for the parameters used in the correction techniques are provided for better understanding the influence of these parameters and for finding out the desirable values. It is found that (1) the SPH method is easily subjected to an inconsistency problem in the boundary area due to the boundary deficiency, and it can be treated well by adopting “virtual particles” contributing to the particle summations. (2) The numerical oscillation in SPH simulation can be mitigated effectively by artificial viscosity with the suggested parameter values. (3) The tension cracking treatment, artificial viscosity and artificial stress work well in removing the tensile instability problem in SPH method. In addition, the nearest neighboring particle searching (NNPS) algorithm, spacing ratio, smoothing length and time step influence the efficiency and accuracy of SPH method significantly. It is shown that SPH method with suggested parameters values can produce a very good result compared with the experimental result. 相似文献
105.
106.
针对单层异形柱框架,通过高温数值分析,考察了支撑设置和受火位置对结构高温变形及内力的影响。研究结果表明:对于单层多跨异形柱框架,当只有一端有支撑跨时,会在一定程度上增大另一端的边节点水平位移和边柱侧向变形,对结构整体抗火不利;当左、右两端均有支撑跨时,非支撑跨在火灾作用下的梁轴力比很大,升温后期可能因梁跨中竖向位移急剧增大而发生破坏。基于上述研究结果,给出了4类单层带支撑异形柱框架火灾行为的初步判定方法。 相似文献
107.
在大连国际会议中心核心筒墙体抗震设计中,采用了一种钢管混凝土叠合边框墙肢内藏钢板、连梁内藏钢桁架的组合双肢剪力墙。为研究其抗震性能,进行了1个1/7缩尺的这种新型组合双肢剪力墙模型的低周反复荷载试验,分析了其承载力、延性、刚度及其退化、滞回特性、耗能能力和破坏特征,重点研究了钢管混凝土叠合边框、墙肢内藏钢板、连梁内藏钢桁架之间的共同工作性能。研究表明:内藏钢板-钢桁架可显著提高钢管混凝土叠合边框双肢剪力墙的承载力和延性性能;钢管混凝土叠合边框可充分发挥其承载力高、不易开裂、延性好的优势。文中提出了该新型组合双肢剪力墙的承载力计算模型,计算结果与实测结果符合较好。 相似文献
108.
109.
S. Salcedo-Sanz J.L. Camacho .M. Prez-Bellido E. Hernndez-Martín 《Journal of Atmospheric and Solar》2010,72(18):1333-1340
In this paper we present a novel method for deseasonalizing TOC data using non-linear models, with evolutionary computation techniques, and its performance with a neural network as regression approach. Specifically, the proposed deseasonalization method uses an evolutionary programming (EP) approach to carry out a curve fitting problem, where a given function model is optimized to be as similar as possible to an objective curve (a real TOC measurement in this case). Different non-linear models are proposed to be optimized with the EP algorithm. In addition, we test the possibility of deseasonalizing the TOC measurement and also the meteorological input data. The deseasonalized series is then used to train a neural network (multi-layer perceptron). We test the proposed models in the prediction of several TOC series in the Iberian Peninsula, where we carry out a comparison against a reference deseasonalizing model previously proposed in the literature. The results obtained show the good performance of some of the deseasonalizing models proposed in this paper. 相似文献
110.
因其特殊的地质成因,柱状节理成为一种具有强烈非连续性及各向异性的特殊岩体结构。以白鹤滩水电工程设计、建设中所遇到的柱状节理玄武岩体为背景,针对柱状节理岩体的等效变形模量问题,在探讨了其结构效应表征参数的基础上,利用节理网络有限元为工具,研究各结构效应表征参数对柱状节理岩体等效变形模量的影响。研究结果表明:在柱轴线横向平面上,对于柱体不规则程度,当柱体完全不规则相对于完全规则情况,等效模量提高大约10%左右;在其他条件不变情况下,当柱体平均边长从0.1 m增加至0.5 m时,等效模量从5.36 GPa增加至23.4 GPa;对不同加载方向的研究结果表明,柱状节理在柱轴横向平面上可以视作各向同性;当节理刚度线性递增时,相应的岩体等效模量也基本符合线性递增的规律。在平行柱体轴线平面,节理组2间距越大,柱状节理岩体的等效变形模量越大;随着错距比的增加,柱状节理岩体的等效变形模量呈现先增加后减少的趋势,当错距比为50%时,节理岩体的等效变形模量取最大值;对于节理刚度的影响,与柱轴横向平面类似的,随柱体轴线平面上节理刚度的线性增加,相应的岩体模量也基本符合线性递增的规律。该研究成果与已有的现场研究成果及三维数值模型成果相比,吻合良好。说明了文中提供的研究结论具有较好的可信度及参考价值。 相似文献