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根据局部变形地基梁法,利用改进了的压力拱理论计算地层压力,对212国道某一隧道衬砌(变截面直墙拱)进行了内力计算,同时利用大型有限元进行模拟,分析了拱形结构的受力特点,对隧道工程的设计与施工都具有一定的指导作用. 相似文献
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针对钢管混凝土拱肋稳定性评估指标单一的问题,提出了一种基于逆可靠度分析的拱肋稳定安全系数评估方法。该方法通过一次逆可靠度算法将稳定安全系数和可靠指标联系起来,求得的稳定安全系数满足预先给定的目标可靠指标,同时考虑结构中存在的不确定性因素,从而建立起具有目标可靠指标和稳定安全系数的拱肋稳定性评估方法。运用所提方法对一工程实例进行计算,并进行参数分析。计算结果表明,随着目标可靠指标的逐渐增加,拱肋稳定安全系数呈递减趋势;折减系数对拱肋稳定安全系数的影响显著,钢材强度对拱肋稳定安全系数的影响相对较小。 相似文献
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对某石拱桥的原设计、病害状态以及加固后的三种状态进行了结构模拟分析,得到了三种不同状态下各自的可靠度和受力情况,从而得出采用套拱法加固该类型的桥梁具有良好的加固效果,具有较为广阔的应用前景。 相似文献
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应用基于神经网络的随机有限元,把截面抗压强度条件视为承载能力极限状态,进行某高速公路不等跨连拱隧道衬砌结构可靠度分析,得出了衬砌结构可靠指标的分布规律和衬砌结构的概率破坏规律。进行衬砌结构可靠度对随机变量的敏感性分析,得出随机变量的分布类型与变异系数对可靠指标的影响规律。结论对隧道设计与施工具有参考价值。 相似文献
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在对目前国内外盾构隧道衬砌结构设计中普遍采用的自由变形圆环法和弹性地基梁法进行比较分析后,针对盾构隧道下穿铁路,盾构隧道管片衬砌承受列车荷载引起的附加动应力进行了研究,提出了自由变形圆环法与弹性地基梁法相结合,基于弯矩与轴力转换系数的计算新方法计算承受偏应力的管片衬砌内力,同时对上海轨道交通线某下穿工点进行了算例分析. 相似文献
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SANDRA L. HOUSTON WILLIAM N. HOUSTON J. MANUEL PADILLA 《Computer-Aided Civil and Infrastructure Engineering》1987,2(3):207-222
Ageotechnical engineering microcomputer program has been developed for the determination of permanent slope displacements resulting from earthquake shaking. The Newmark procedure, in which accelerations in excess of yield accelerations are double integrated to obtain displacements, has been incorporated into the program DISPLMT. Several user options are available for describing the yield acceleration function, including variation with time and variation with displacement. Screen graphics are available which allow the user to observe the down slope movements of the Newmark sliding block as they increase with time during the simulated earthquake. DISPLMT has been used to calculate the permanent movements of an earth dam using acceleration-time histories and soil shear stresses determined from a separate analysis. Modification to the conventional Newmark procedure, by introduction of a "slip layer," has been made in the analysis of a dam. Permanent slope displacements can be analyzed using the recommended procedure, which involves fairly simple computations that can be performed in a reasonable period of time with the exclusive use of microcomputers. 相似文献
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传统概率可靠性分析方法应用重力坝结构性能和服役性态评估过程中,其受不确定参数严格随机性、计算结果对参数过敏感性及其功能函数高度非线性等多因素制约。提出了基于区间参数的重力坝单元和体系非概率可靠性(Nonprobabilistic Reliability,NR)分析方法。首先,充分依据重力坝原型监测资料、数学模型和物理模型计算成果获取重力坝区间参数的界限,综合运用区间数学和NR等理论和方法,构建了基于区间参数的重力坝单元与体系NR计算模型,发展了一种基于响应面方法的重力坝NR指标(NR-η)计算方法。其次,从重力坝系统可能失效路径及失效模式入手,剖析单一和多重失效模式下重力坝体系的安全性。最后,通过某重力坝工程表明:方法能够有效地揭示重力坝局部和整体可靠状态,计算结果符合重力坝运行特点前提下与该大坝服役背景状况高度吻合。 相似文献
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针对混凝土面板堆石坝的工程特点,通过对坝体填筑施工系统进行分析,提出了建立坝体三维实体模型的方法;根据坝体填筑模拟机制和模拟规则建立了坝体填筑仿真模型。最后通过对某大坝填筑方案的分析对比来对系统的合理性进行了论证。 相似文献
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静动力作用下高拱坝坝肩稳定性三维分析 总被引:1,自引:0,他引:1
按照静载设计、动载复核的设计原则,基于地质勘测资料,针对坝肩抗滑稳定问题的三维特性,采用关键块体理论来识别和描述被结构面切割的岩体,确定相应的控制性滑块,进而运用程序实现三维刚体极限平衡法,选取不同高程的试算面对某水电站300 m级高拱坝左、右岸坝肩的静动力抗滑稳定性进行计算分析。在动力分析中,将坝体、库水及其地基作为整个体系,充分考虑坝体、地基和库水三者的动力相互作用。静动综合计算分析的结果表明,拱坝左、右岸坝肩在静力作用下是安全的,且安全富裕较大;在地震作用下也是安全的,但安全裕度不大。这为该拱坝的设计和论证提供了重要的科学依据。 相似文献
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以ADINA软件为例,提出联合开发和调用外部控制程序、自带本构模型二次开发接口、相关计算模块及前后处理模块的思路,全程自动实现各模块的调用计算和数据间的相互传递,一次性完成土石坝静动力反应的精细求解,综合开发时仅对软件自带二次开发接口不能实现的功能进行外部程序编写。通过与著名动力计算程序SHAKE91经典算例的对比分析以及一高土石坝三维静动力反应的工程应用,表明所建议的方法功能拓展性强,数据传递高效快捷,且计算结果合理可靠。这一方法也可推广用于ABAQUS和ANSYS等商业有限元软件,以弥补这些软件在精细求解某些特定问题时自身的不足。 相似文献
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David B. Parkinson 《Engineering Structures》1980,2(1):57-62
A computer procedure to calculate the second moment reliability index for any linear or nonlinear failure condition has been developed and is presented in the form of a Fortran subroutine. The program calculates reliability index by an iterative numerical procedure and, in addition, provides information regarding the relationship between reliability index and failure probability to enable a suitable approximation to be chosen for the latter. An example is provided to illustrate the use of the program in computing a value for the reliability index and in carrying out a sensitivity analysis. Listings are provided of the reliability index subroutine together with ancillary programs employed in the illustrative example. 相似文献
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Even though a large number of large-scale arch dams with height larger than 200 m have been built in the world, the transient groundwater flow behaviors and the seepage control effects in the dam foundations under difficult geological conditions are rarely reported. This paper presents a case study on the transient groundwater flow behaviors in the rock foundation of Jinping I double-curvature arch dam, the world’s highest dam of this type to date that has been completed. Taking into account the geological settings at the site, an inverse modeling technique utilizing the time series measurements of both hydraulic head and discharge was adopted to back-calculate the permeability of the foundation rocks,which effectively improves the uniqueness and reliability of the inverse modeling results. The transient seepage flow in the dam foundation during the reservoir impounding was then modeled with a parabolic variational inequality(PVI) method. The distribution of pore water pressure, the amount of leakage, and the performance of the seepage control system in the dam foundation during the entire impounding process were finally illustrated with the numerical results. 相似文献