高速公路软基路段施工期间沉降监测与分析

简述了福建某高速公路软基路段施工期间软基沉降监测的埋设及测量方法,根据观测的沉降资料,统计平均沉降速率和绘制沉降-荷载-时间曲线图,并进行分析和判断路基沉降的稳定性,其后尝试应用双曲线法对路基的工后沉降进行预测。     

实例工程铁路路基下大直径管线保护方案的比较

大直径原水管线下穿铁路路基时会引起路基沉降,并且列车荷载亦会增加水管的应力和变形,须对水管结构采取保护措施,减小路基沉降和水管受力,可采用的措施有:架桥法、箱涵法、套管法、地基加固法,本文结合具体工程对几种方案进行有限元计算,并比较其处理效果和经济性,指出其适用性。     

大跨径钢桁梁拱桥变形监测方案设计与精度分析

桥梁在运营过程中由于受到外部因素破坏及内部性能退化等影响,桥梁的安全性、适用性和耐久性都会降低,为了保证桥梁的安全运营,必须对其进行健康监测及安全评估。本文结合工程实例详细介绍了大跨径桥梁变形监测的基准网建立、变形点布设原则和数据监测,并对位移和沉降观测进行精度分析等,为同类型桥梁健康安全监测和运营管理起参考借鉴作用。     

柳州维义大桥桥墩沉降监测运用中点三角高程测量方法的精度分析

随着测距技术的发展、测距精度的提高,三角高程测量方法正逐步受到广大测绘工作者的青睐,本文通过工程实例,介绍了运用中点三角高程测量对离岸桥墩进行沉降监测的方法,并对这种测量方法的误差来源及精度进行了分析。阐述了这种测量方法在工程测量运用中的高效性、灵活性和实用性。     

碎石桩处理可液化层和软土层交互地基沉降特性

本文总结分析了碎石桩处理由可液化层和软土层交互组成地基的沉降历时曲线线型特点,沉降量与填土高之间关系,沉降历时曲线线型特点及硬壳层和软土层厚度对沉降变形的影响,同时也讨论了沉降速率与填土速率之间的关系。该分析成果能够估算碎石桩处理地基的沉降,并解释了硬壳层和软土层厚度变化对沉降变形的影响。     

成桩工艺对桩基沉降的影响

通过上海饱和软粘土中３５座桩基实测沉降资料对比,表明在工程条件十分接近的条件下钻孔桩基的沉降小于打入桩基,显示成桩工艺对桩基沉降的影响。并根据打桩引起的桩负摩阻力概念对两类桩基沉降差异的机制作了分析。     

我国电信网间互联结算之浅见

从如何评价当前我国的网间结算标准、要建立合理有效的网间结算体系应该处理好哪些方面的问题以用建立网间结算体系应注意的重点三个方面．阐述了对我国电信网间互联问题的观点。指出网间结算是电信互联互通和会平竞争的基石,其实质是对各电信运营企业的业务收入进行再分配,因此新的网间结算方案将永远不会让各方都满意。     

Dynamic response of Mechanically Stabilised Earth (MSE) structures: A numerical study

With increasing construction feasibility, lower costs and proven performance throughout past major seismic events, MSE retention systems have become one of the more preferred retention systems. To study the dynamic performance of MSE walls, the 2D FE simulation using the OpenSees programme with the Manzari and Dafalias constitutive relationship has been utilised. A series of one-dimensional (1D) and 2D site response analyses subjected to sinusoidal inputs at various frequencies have been conducted to find the natural period of the soil medium. Then, using three earthquake time-histories recorded on engineering bedrock (Vs > 700 m/s), the behaviour of MSE walls with geogrid length to wall height ratios of 0.50 and 0.75 has been investigated. Multi-pulse Ricker wavelets have been deployed for a closer inspection of possible failure mechanisms of these MSE walls. Finally, the possibility of simulating an elastic orthotropic block instead of the reinforced soil with geogrids has been examined.     

越江隧道抗震稳定性计算

根据越江工程场地地震安全性评价报告和地质调查报告，在室内动力试验的基础上，采用有限元有效应力动力分析法，研究了隧道结构的动力响应和地基土的液化情况，利用拟静力法对隧道抗滑稳定性进行了校核，得出了该隧道抗震稳定性满足要求的结论，并提出了能进一步增强隧道抗震性能的建议。     

A quasi-2D exploration of optimum design settings for geotextile-reinforced sand in assistance with PIV analysis of failure mechanism

Many earlier studies were focused on testing different types of geosynthetics to investigate effect of reinforcement on bearing capacity, but the effect of tensile strength on the failure mechanism has not been examined sufficiently. Within this scope, a test setup was prepared to apply strip loads on densely compacted reinforced sand under the plane strain condition. The tank containing the reinforced sand was a rectangular prism with perfect transparency, and its interior dimensions were 960 × 200 × 650 mm³. Firstly, optimum values of design variables (depth of first sheet, length and number of sheets, space between sheets, tensile strength of sheets) for the woven geotextile reinforced sand were determined experimentally. Then, the failure mechanisms of the soil, which were reinforced with geotextiles of different tensile strengths, were observed and analyzed with particle image velocimetry (PIV) technique. Consequently, the failure mechanism of the sand with a single geotextile reinforcement was similar to general shear failure of unreinforced soil. Contrarily, the failure surfaces were deeper and longer. Additionally, the deep-footing mechanism reached out large depth in the case of four reinforcement layers. The failure mechanism converted into a punching type due to a hypothetic increase in the bearing depth of reinforcement.