共查询到18条相似文献,搜索用时 687 毫秒
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目前国内基本都采用传统压浆法进行孔道灌浆,这种方法普遍造成灌浆不密实,预应力钢铰线易于锈蚀.近年来推出的真空辅助压浆法灌浆工艺,可以较好地解决此类问题.对真空灌浆技术原理及其实际工程应用进行了阐述. 相似文献
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针对国内深厚软土地区盾构下穿改扩建堤坝变形安全控制问题,文章依托上海某典型软土盾构隧道下穿待改扩建堤坝工程,通过对比不同加固方式确定了真空联合堆载预压加固法,现场实测了真空联合堆载预压加固堤坝期间地层变形和孔压变化规律以及盾构下穿期间改扩建堤坝表层变形和隧道自身变形。结果表明:采用真空联合堆载预压加固方法可较好地控制盾构下穿改扩建堤坝的施工风险,真空联合堆载预压法对常规埋深盾构隧道下方约2倍盾构直径范围内的软土有加固效果,双曲线经验法能较好预测软土地区老旧大堤预压加固作用下的地基沉降,盾构穿越预压加固的大堤引发的固结变形沉降较小。 相似文献
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对目前国内施工隧道的主要通风方式进行分析,通过实测数据阐述了爆破后通风过程粉尘运移规律,指出了隧道施工过程中主要污染源以及空气净化技术存在的问题.在此基础上.提出了压出式空气幕通风技术.通过数值模拟方法,比较了压入式隧道通风与压出式空气幕隧道通风效果.结果表明,压出式空气幕通风技术可以降低隧道施工中的粉尘和烟尘,改善隧道作业空气环境,其通风效果更优越. 相似文献
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原油顺序输送的现状与展望 总被引:2,自引:0,他引:2
通过对国内外现有油品顺序输送管道的发展情况的了解,以及对国内外油品顺序输送中的混油机理、界面检测、界面隔离、减少混油措施等现有技术进行总结,对国产原油-进口原油顺序输送所应解决的问题进行了阐述,最后提出对顺序输送技术的展望,并提出应该急需研究的油品顺序输送所应注意的相关技术问题。 相似文献
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文章介绍了秦岭终南山特长公路隧道通风系统规模以及国内外竖井的主要施工方法及各自的适用条件和优缺点;同时结合秦岭终南山公路隧道通风竖井的设计,探讨了其适用的施工方法,为类似工程提供参考依据。 相似文献
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文章通过了解国内外油气回收的相关规范及建设油气回收设备的相关要求,熟悉吸收法、冷凝法、吸附法等传统油气回收工艺以及在此基础上衍生出的相关组合工艺,并对其技术特点进行对比。同时,针对国内外相关港口油气回收设备的应用情况进行分析,得出现有港口油气回收设备的应用存在相关政策法规缺失、安全风险及船舶配套不完善等难题。 相似文献
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注浆是土木、水利和矿山等工程建设中重要的防渗和加固技术。文章基于国内外注浆技术研究文献,总结了水泥等颗粒性浆液的“渗滤效应”及“黏度时空变异性”等理论研究成果,论述了非水反应高聚物、CW环氧树脂和微生物菌液等注浆新材料的应用现状及发展前景,介绍了细观力学数值模拟研究的突破性进展,可为地下工程注浆技术发展提供借鉴和启发作用。 相似文献
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《Transportation Research Part C: Emerging Technologies》2001,9(3):175-190
The problem of pavement maintenance management at the network level is one of maintaining as high a level of serviceability as possible for a pavement network system through reactive and proactive repair actions, whilst optimising the use of available resources. This problem has traditionally been solved using techniques like mathematical programming and heuristic methods. Lately, the use of genetic algorithms (GAs) to solve resource allocation problems like the network pavement maintenance problem has received increased attention from researchers. GAs have been demonstrated to be better than traditional techniques in terms of solution quality and diversity. However, the performance of the GAs is affected by the method used to handle the many constraints present in the formulation of such resource allocation methods. Penalty as well as generate and repair methods are the usual techniques used to handle constraints, but these have their drawbacks in terms of computational efficiency and tendency to get trapped in sub-optimal solution spaces. The paper proposes a third method that is computationally more efficient than the previous methods. The method is based on prioritised allocation of resources to maintenance activities and the maximum utilisation of resources. Constraints on maximum resource availability are no longer used passively to check on solution feasibility (as in the previous methods) but are used to help generate feasible solutions during the resource allocation phase of the algorithm itself. It is demonstrated that the GA with the prioritised resource allocation method (PRAM) outperforms the traditional GA with repair or penalty methods. PRAM was able to consistently outperform the other two GA based methods, both in terms of solution quality as well as computational time. It is concluded that PRAM can be used as the basis of more efficient resource allocation procedures in the area of pavement maintenance management. 相似文献