阻尼器力学性能的试验方法与分析

根据阻尼器的加载过程分析,提出了阻尼器耗散功率概念。对耗散功率谱法和传统滞回曲线法在评价阻尼器耗能能力方面进行了比较,特别在复杂加载情况下,耗散功率谱法具有显著的优点。通过对单调加载中因加载波形不同而导致耗能的变化的分析,提出了阻尼器耗能性能的综合评价方法。     

基于应力场的土坡临界滑动面的蚂蚁算法搜索技术

在土坡应力场非线性有限元分析的研究基础上，将蚂蚁算法这一新的启发式人工智能型优化方法与土坡稳定性有限元分析方法相结合，探讨了基于有限元分析得出的土坡应力场所对应最小稳定安全系数的土坡任意形状临界滑动面的蚂蚁算法搜索技术，并通过分析算例说明这一技术的可行性。     

电能回馈式传动系疲劳寿命试验台的研制

为解决现有传动系疲劳寿命试验台能耗大的问题,研制开发了一种以直流测功电机为加载器、数字直流可逆调速器为控制器,将直流测功电机产生的电能回馈到电网的传动系疲劳寿命试验台。该装置的电能回馈率达76%左右,节能效果显著。     

东港高速公路软土路基的处理办法研究

结合东港高速公路工程实例,对公路软土路基的土层组成进行了分析,提出了四种不同的软基处理方法并进行了详细阐述,研究了不同地基处理方法交接部位的过渡处理,可供类似工程参考借鉴。     

8度区异形柱框架-剪力墙结构的振动台试验研究

为了对比异形柱框架-剪力墙结构与框架结构在抗震性能、破坏机理等方面的异同,探讨其在高烈度地震区的适用性,根据相同的背景情况设计制作了一个1/8比例的10层异形柱框架-剪力墙模型,进行了振动台试验。根据设计计算的结果和振动台试验中出现的现象及其分析,研究了计算方法的适用性、结构的总体抗震性能和破坏机制。指出该体系具有易于满足位移要求、在大震中以梁铰机制为主、抗倒塌能力强等特点;同时通过与框架结构破坏现象的对比,说明了这种体系可以有效地解决节点承载力问题,在高烈度区应用异形柱结构时应优先采用。     

Optimal design of composite multilayered plated and shell structures

For multilayered plated and shell structures the formulation of the optimization problem is strongly dependant on the definition of the design variables. Therefore, the first part of the work is devoted to the definition of design variables and the forms of objective functions. Then, two numerical examples have been solved to demonstrate the effectiveness of the proposed formulations and the optimization algorithm (the modified evolutionary strategy). They deal with thickness and shape optimization problems subjected to dynamic and static constraints, respectively.     

物理改性聚羧酸系高效减水剂的正交试验研究及对混凝土性能的影响

通过正交试验方法对聚羧酸系高效减水剂进行物理改性,并分析了减水效果、流动性保持能力以及强度三个指标的显著性影响因素,并通过综合考虑确定了复合型聚羧酸系高效减水剂的最佳配方.并以选取的配方进行了性能检测及其混凝土的相关耐久性试验,结果表明该复合型聚羧酸系高效减水剂具有高减水、高增强、适当的缓凝以及优异的耐久性.     

Stability assessment of the Three-Gorges Dam foundation, China, using physical and numerical modeling—Part I: physical model tests

Foundation stability is one of the most important factors influencing the safety of a concrete dam and has been one of the key technical problems in the design of the Three-Gorges Project. The major difficulties lie in two facts. The first one is that the dam foundation consists of rock blocks, with joints and so-called ‘rock bridges’ and the gently dipping joints play a critical role in the foundation stability against sliding. The second one is that, even in the regions where the gently dipping fractures are most developed, there are no through-going sliding paths in the rock mass due to the existence of the rock bridges; so the dam could slide only if some of the rock bridges fail, so as to create at least one through-going sliding path. To date, due to unavoidable shortcomings in physical and numerical modeling techniques, there is not a single satisfactory method to solve the problem completely. For this reason, the integration of multiple methods was adopted in this study and proved to be an effective and reliable approach.This Part I paper describes work based on the results of geological investigations and mechanical tests, relating to the geological and geomechanical models of the Three-Gorges Dam, and then a systematic study procedure was developed to carry out the stability assessment project. Then, 2D and 3D physical model tests for some critical dam sections were performed. In the physical tests, based on similarity theory, various testing materials were selected to simulate the rock, concrete, fracture and rock bridge. The loading and boundary conditions were also modeled to meet the similarity requirements. The failure mechanism was derived through a progressive overloading that simulated the upstream hydrostatic pressure applied to the dam, and the factor of safety was defined as the ratio between the maximum external load inducing the start of sliding instability of the dam foundation and the upstream hydrostatic load. The experimental results indicated that the stability of the Three-Gorges Dam foundation satisfies the safety requirements. Nevertheless, further discussions demonstrated that because of the incomplete definition of factor of safety adopted in the physical model tests, it is also essential to study the stability of the Three-Gorges Dam foundation using numerical modeling, which will be presented in the companion Part II paper.     

混凝土强度检验评定标准的问题与对策

混凝土强度的正确评定是混凝土分项工程质量验收与评定的主要组成部分,也是工程质量控制的重要内容。现行的混凝土强度的检验和评定是以《混凝土强度检验与评定标准》GBJ107-87为主要依据。为此,结合数值模拟对标准中的各种评定方法进行了全面的分析比较,总结该检验评定标准存在的问题,并从风险平衡的角度提出新的对策。     

屏蔽混凝土用原材料性能试验研究

选择国内生产的蛇纹石、磁(赤)铁矿石、褐铁矿石、重晶石、硼镁铁矿石、钢丸、钢锻和越南产的铬矿粉等屏蔽混凝土用矿石原材料和P·O硅酸盐水泥及铝酸盐水泥,通过对其骨料典型性能试验、热稳定性能试验、颗粒级配试验及水泥结晶水测试方法试验研究,总结出了组成屏蔽混凝土用的各种水泥和矿石的性能特点,找出了屏蔽混凝土用矿砂最优级配曲线,提出了水泥结晶水测试方法,以指导屏蔽混凝土用原材料的正确选用和水泥结晶水的测试.