上跨既有地铁的隧道基坑的设计与施工研究

梅西湖隧道基坑k24 +510 ～560段上跨地铁2号线,基坑底部离地铁衬砌只有3.3m,为了基坑及地铁衬砌的安全,采用上部桩锚+下部土钉墙的支护型式度过本段基坑,并用midas数值计算软件对基坑开挖进行计算,得出了地铁衬砌的竖向位,以此来探讨地铁衬砌的安全性,对类似工程的设计和施工有一定的借鉴意义.     

Support condition monitoring of monopile-supported offshore wind turbines in layered soil based on model updating

Monopile-supported offshore wind turbines (OWTs) are dynamically sensitive structures whose fundamental frequencies may be close to those of environmental and turbine-related excitations. The changes in fundamental frequencies caused by pile-soil interaction (PSI) may result in unwanted resonance and serious O&M (Operation and Maintenance) issues, which have been identified as major challenges in the research field. Therefore, a novel model updating framework with an implicit objective function is proposed to monitor both the stiffness and damping variation of the OWT system based on the measured vibration characteristics, which is further verified by laboratory tests. In particular, layered soil was considered in the tests to simulate the practical soil conditions of Chinese seas. Different pile lengths were introduced to consider the long-term PSI effects for rigid piles and slender piles. The results showed that the variation in the fundamental frequency is significantly reduced in layered soil compared with the pure sand scenario. For the OWT systems in layered soil, the variation in foundation stiffness is negatively related to the burial depth under cyclic loading. The proposed model updating framework is proven reliable for support condition monitoring of OWT systems in complicated soil conditions.     

基于三角模糊数-TOPSIS的既有高铁近接地基加固方案优选

邻近既有高铁新建线的地基加固会严重影响既有高铁运营安全,地基加固方案优选是近接工程研究的焦点问题之一,但目前针对近接工程地基方案优选研究较少。结合既有高铁近接工程特点,在综合考虑影响地基加固方案选择因素基础上,建立地基加固方案优选指标;提出基于三角模糊数-TOPSIS优选模型,并将其应用于新建曲阜至临沂线近接京沪高铁地基加固方案优选进行分析验证。研究结果表明:该模型对于近接既有高铁地基加固方案优选具有一定可靠性与实用性,不仅为近接地基加固方案优选提供了一种新方法,同时为建立近接工程类似项目的综合评价指标和优选方案奠定了理论基础。     

水泥土搅拌桩桩身强度影响因素的正交层次分析

在江苏省连盐高速公路连云港试验段,根据场地的地基条件,在室内配比试验的基础上,进行了多种配比和不同施工工艺的水泥土搅拌桩成桩质量研究。运用正交试验数据分析方法探讨水泥的掺入量、搅拌次数和地基土含水量等因素对水泥土搅拌桩桩身强度的影响。结果表明:正交层次分析法可以得出各因素对桩身强度影响的权重,除了水泥掺入量对成桩质量有决定性影响外,地基土含水量也有较大的影响,在一定的范围内搅拌次数影响不大。在此基础上为更好地控制水泥土搅拌桩现场施工质量提出了建议。     

Influence of Pit Foundation Excavation on an Adjacent Metro北大核心CSCD

With the development of urban metro systems, the influence of foundation pit construction on metro fa-cilities and related protection measures are getting more and more attention. A technical program for metro assess-ment at different phases of foundation pit construction is proposed using the statistics and analysis of a foundation pit of the Hangzhou metro. Qualitative and quantitative methods for analyzing the influence that foundation pit exca-vation has on metro systems are studied, and a series of protective measures suitable for foundation pit construction are summarized. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

基金会现场总线在FPSO上的应用

首先介绍了基金会现场总线的概念、体系结构，并通过应用于文昌FPSO上的具体实践，阐述了基金会现场总线具有技术先进、功能强大以及操作维护便利等优点；同时又提到了在实际应用中总线技术的局限性；最后展望了总线技术的未来发展。     

提高对公路统计工作的认识加强公路统计分析职能

从对公路统计工作的作用、特点，重点论述了在完成统计基础工作的同时加强统计分析的重要性。     

S7-300PLC构成PROFIBUS-DP网络的原理及应用

讨论用PLC构成PRORBUS-DP网络系统的方法.首先介绍DP网的概念和实现,然后结合一个实际的例子来着重阐明用PLC来实现DP网络的解决方法.     

图解Photoshop蒙版的效用

文章阐述了Photoshop CS2中蒙版的类别和作用,用图例重点展示了图层蒙版在抠取图像、合成图像、制作透明效果方面的效用,让使用者深刻领会图层蒙版的应用目的及蒙版应用到图片上达到的效果．     

龙江大桥高水位筑岛桥墩基础施工技术

文章结合龙江大桥3#墩基础施工实例,对桥墩高水位筑岛围堰的施工方法进行探讨,着重介绍了土石筑岛围堰、水下承台施工等桥墩基础施工技术。