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Snow load on mesh systems is complicated by many factors. This paper presents field instrumentation data on snow load variation with temperature, snowfall and snow depth on a mesh system. It was found that snow load pattern on mesh systems changed with temperature even without variation in snow depth. It reached its maximum value when the temperature rose just above freezing to melt the interface. The field data was used to formulate appropriate snow load models for the various conditions of temperature in the field. The snow load models were used to study the performance of a number of mesh systems in North America and estimate the interface friction that was prevalent for the different surface conditions. 相似文献
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Load testing of anchors for wire mesh and cable net rockfall slope protection systems 总被引:1,自引:0,他引:1
Shanzhi Shu Balasingam Muhunthan Thomas C. Badger Robert Grandorff 《Engineering Geology》2005,79(3-4):162-176
This study presents results of field tests conducted on anchors used to support wire mesh and cable net rockfall protection systems. The load transfer and failure characteristics of these anchors are different from those used in most civil applications in that loads are often applied transversely to the top of tendon rather than axially. The study included vertical as well as horizontal series of tests conducted on some anchors widely used in wire mesh and cable net rockfall protect systems. It was found that the deformation characteristics of these anchors under vertical loading are nonlinear. They are approximated by a hyperbolic formulation and used to calculate the ultimate capacity. Top-downward progressive cracking of the grout was observed during loading and influences the deformation characteristics of these anchors under horizontal loading. The anchors deflected excessively before they could attain their ultimate capacity in the horizontal direction. Based on the field tests, it appears that the deformation under horizontal loading in the systems can be limited by using an enlarged grout zone at the top. 相似文献
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转变消费模式实现可持续发展 总被引:1,自引:0,他引:1
通过大量的事实数据,阐述了现行消费的不可持续性,认为全球环境不断恶化的主要原因是不可持续消费和生产模式。并从可持续发展观念出发探讨了什么是可持续消费,指出了在不同的经济发展阶段,可持续消费模式是不同的,发展中国家盲目仿效发达国家高额物质消费是不现实的,也是不可持续的。最后,提出了实现消费模式转变的4条主要途径。 相似文献
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干湿循环作用下压实黄土湿陷特性试验研究 总被引:4,自引:0,他引:4
压实黄土作为重要的填筑材料,广泛应用于我国西北、华北公路、铁路、机场等基础设施建设中.由于降雨及蒸发的周期性变化,黄土路基及基础经历着强烈的干湿交替作用.基于此,开展压实黄土风干干燥-滴水增湿条件下的干湿循环试验,利用双线法测试最佳含水量条件下不同初始压实度的黄土土样干湿循环前后的湿陷系数.结果表明:没有经历干湿交替作用的土样,湿陷系数随着压实度的增大而快速减小,当压实度达到90%,提高压实度对于黄土湿陷变形特征的影响较小;5次干湿循环作用后,不同压实度下的试样的湿陷系数均明显增大,且压实度越大,干湿作用对其湿陷变形的影响越显著;压实度K=95%试样在经历5次干湿循环作用后土样上部出现肉眼可见的细微孔隙,体积膨胀,有可溶盐析出,湿陷系数达到0.017,土样出现二次湿陷. 相似文献
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Acta Geotechnica - The Jurassic Badaowan formation of the tight oil reservoir in northwest Xinjiang, China, is featured by a complex in situ stress pattern, leading to an unclear... 相似文献
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