黏土的结构性定量化表征及其弹塑性本构模型研究

结构性可增强土骨架的稳定性,在相同的应力条件下,结构性土与重塑土相比可保持更大的孔隙比.从结构性土的形成过程出发,详细分析了结构性对土体变形特性的影响及变形过程中结构性的衰退规律,提出了土体结构的定量化表征参数——相对结构度,并给出了该变量在土体变形过程中的演化方程.随后基于该参数推导了结构性土的体变方程,该方程反映了...     

Technical report on the compression,structure, and creep behaviors of lacustrine soil deposits in Bogotá, Colombia

This technical report on the compression behavior of soft soils in the Colombian capital, Bogotá, was conducted because the city’s recent construction history has led to excessive settlement of soils in the city over the last forty years. Several studies have shown the city’s soil to contain unusually high concentrations of diatoms. The stationary piston method was used to obtain samples from depths of between five and 100 m. Samples were subsequently examined in the laboratory, being subjected to triaxial and oedometer compression tests, and tested also for Atterberg limits and grain size distributions. Test results for undisturbed soil returned very high liquid limit values, compressibility indices C_C, secondary compression coefficients C_α, and soil structure effects. Some samples showed particle mixtures of different sizes, mineralogy, and diatom concentrations. Although high C_C and C_α indices explain the excessive settling of the city’s buildings, most construction projects do not currently take settlement caused by secondary compression into account. This report shows that secondary compression is an important parameter in the total settlement of buildings in Bogotá and that, furthermore, settlement is also affected by geological history. Finally, useful correlations such as the relationship between the liquid limit, C_α and geological history are presented.     

Damage detection in beam-like structures using static shear energy redistribution

In this study, a static shear energy algorithm is presented for the damage assessment of beam-like structures. According to the energy release principle, the strain energy of a damaged element suddenly changes when structural damage occurs. Therefore, the change in the static shear energy is employed to determine the damage locations in beam-like structures. The static shear energy is derived from the spectral factorization of the elementary stiffness matrix and structural deflection variation. The advantage of using shear energy as opposed to total energy is that only a few deflection data points of the beam structure are required during the process of damage identification. Another advantage of the proposed approach is that damage detection can be performed without establishing a structural finite-element model in advance. The proposed technique is first validated using a numerical example with single, multiple, and adjacent damage scenarios. A channel steel beam and rectangular concrete beam are employed as experimental cases to further verify the proposed approach. The results of the simulation and experiment examples indicate that the proposed algorithm provides a simple and effective method for defect localization in beam-like structures.     

分区中社区配套设施用地规划的探索——以无锡市分区规划为例

社区是城市的基本单元,完善社区配套是城市规划的重要内容之一。本文以无锡市分区规划为例,在分区规划阶段确定社区规模、社区配套设施及用地控制指标,为社区建设和管理提供决策依据。     

L型广义扩张原理及其在模糊集范畴中的应用

首先给出了L型模糊集的广义扩张原理,并讨论了它的基本性质;然后定义了两个L型模糊集范畴■(L)与■(L),并证明了范畴■(L)与范畴Set同构且范畴■(L)同构于范畴■(L)的一个子范畴.研究结果可应用于泛型信息处理设计.     

选矿生产指标可视化监控平台研究

针对选矿工业过程流程长、工序多、生产指标多的特点,结合数据可视化及可视分析技术,开发一种选矿生产指标可视化监控组态平台。该平台包括生产工艺可视化组态设计环境、生产指标监控和可视及可视分析3个工具。组态设计环境支持以组态方式绘制工艺流程图,并能通过可视界面自定义生产工序的输入输出指标、触发事件、约束规则、工序状态属性、提示信息等;支持集成专家知识、经验和规则以实现基于知识的生产指标监控;提供算法配置接口,方便集成指标监控算法。其组态出的每一个工序都可以复用和扩展,可以构建选矿行业的基础工序单元组件库,形成选矿行业的知识积累。基于可视的工艺流程,利用指标监控工具为指标配置可视化方案,实现指标可视化监控。可视化方案由可视及可视分析工具提供,包括实时数据、历史数据及其统计特性、多指标综合对比分析、指标关联关系分析、多视图等可视方案。此外,为了提升工序指标监控效率和减轻操作人员监控强度,系统提供因子分析、Pearson相关分析、互信息、信息熵等分析手段,以辅助人们提取出工序关键监控指标,从而实现对监控生产指标的约简。由于该平台以组态方式提供,使其可以快速应用于其他流程行业,实现生产指标可视化监控的组态化。最后,该系统作为选矿生产执行系统的一部分成功应用到某选矿厂生产过程中,取得了良好的应用效果。     

强夯法处理某野外放飞试验场膨胀土新素填土地基的工程实践

简要介绍了采用强夯处理某野外放飞试验场膨胀土新素填土软弱地基，为江淮丘陵坳沟洼地开发建设场地广泛分布此层新素填土地基处理提供了一次有参考作用的岩土工程实践。     

聚丙烯纤维和丁苯乳液对水泥砂浆性能的影响

研究了掺量为0~0.3%(体积分数)的聚丙烯纤维,掺量为0~12%(质量分数)的丁苯乳液在单掺、复掺情况下对水泥砂浆3,28,90 d抗压、抗折强度,以及28 d龄期时磨损、冲击性能等的影响.研究结果表明,纤维的掺入大幅度提高了丁苯乳液砂浆的抗冲击和抗磨损性能,提高丁苯乳液砂浆抗磨损性能的最佳纤维掺量为0.1%;纤维掺量越大,对提高丁苯乳液砂浆的抗冲击性能越有利.丁苯乳液的掺入改善了聚丙烯纤维与基体之间的界面粘结,增强了掺纤维砂浆的长期力学性能.丁苯乳液、聚丙烯纤维的复掺效果优于这两者单掺的情况,复掺对水泥砂浆起到了双重改性的效果.     

车辙的成因及控制指标

介绍了车辙的种类，分析了发生车辙的原因，阐述了车辙控制指标的计算以及车辙深度的控制标准，从而为公路建设者提供理论指导。     

Fuzzy optimization of cold-formed steel sheeting using genetic algorithms

In this paper, genetic algorithms are applied for optimization of dimensions of cold-formed steel trapezoidal sheeting. The objective of the optimization is to obtain the minimum weight subjected to the given constraints in accordance with Eurocode 3, Part 1.3. In traditional optimization, these constraints are defined with crisp number. However, in practical engineering, constraints with a small certain percentage of violation can be acceptable. Thus, in this research, sheeting is optimized to satisfy the constraints considering the fuzziness so that the optimization is more practical from the engineering point of view. The better performance of introducing the fuzziness into a constraints-handling technique has been demonstrated with a design example.