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文中根据工程实例,利用监测数据,采用规范法和拐点法详细地分析了经过处理后的软土地基在路堤填土分级加载过程中的稳定性.通过两种方法的对比分析得出一致的结论,即湿地软土地基在路堤填土分级加载过程中是稳定的,而且是与工程实际相符的.有效地控制了施工加载过程和指导施工,为今后湿地软土地基稳定性控制提供参考. 相似文献
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复合双曲线法预测公路沉降探讨 总被引：1，自引：0，他引：1
通过施工填土早期的沉降观测资料来推测设计填土高度下的最终沉降量，是在公路工程中急待解决的课题。现提出复合双法来解决这一问题，即利用早期的填土期实测沉降资料对传统双曲线法进行改进，假定地基土为线弹性变形，并考虑实际土的非线性影响，引入一经验修正系数，来推算设计填土高度下的路基最终沉降量。 相似文献
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基于强度折减理论，结合某在建高速公路重点试验路段填石路堤有无码砌边坡，运用有限元软件建立模型，计算其水平位移变形值和边坡稳定性系数，结合现场边坡变形监测数据监测填石路堤的长期性能。 相似文献
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针对路堤填筑在稻田地基上的情况,为避免路基产生长期不均匀沉降,保证本段路基填土质量,采用石灰碎石桩措施进行处理。 相似文献
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论述福州地区城市道桥设计中路堤的经济高度及合理路堤高度,并对砼路面结构层尺寸的合理配合以及特殊路段的砼路面结构层设计进行探讨。 相似文献
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高等级公路的路基填土一般较高,在软土地基上修筑高填土路堤必然会引起地基的较大沉降,而在遇到桥涵、通道等构造物时将产生较大的不均匀沉降,形成“错台”等病害,因此,就需要采取有效处理方法消除或减少不均匀沉降的发生。本文针对当前高等级公路修建中常采用的几种方法加以评述,并认为多种方法并用的综合处理能得到较满意的效果。 相似文献
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结合工作经验,在保持既有的高速公路高填方路堤边坡的稳定性的基础上,对高路堤边坡失稳问题提出了一系列的加固方案,以确保路面结构的加固。 相似文献
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Lloyd C. Irland 《European Journal of Forest Research》2010,129(5):777-786
The UN’s Millennium Development Goals (MDGs) and other regional and national policy commitments have motivated an upsurge
of interest in concepts and practical methods for monitoring forest conditions and trends at very wide geographic scales.
Two approaches to sustainability assessment at a global level are reviewed here. One consists of monitoring change in forest
conditions over time—the so-called Criteria and Indicators (C&I) approach. Another approach compares nations at a given point
in time. An example is the Yale Environmental Performance Index (EPI). Both approaches yield insights. It is widely recognized,
though, that severe data weaknesses afflict forest information over much of the world. These weaknesses include weak or absent
information on wood consumption in many regions, poor area estimates, and weak or absent information on key ecological conditions
in forests. The purpose of this essay is to introduce these efforts at global assessment, and to argue that an entirely new
discipline is needed to supply the information needed. The focus of this new discipline would be to design an ecologically
based set of definitions for forest and related ecosystems, and then to build and implement the optimum combination of satellite
measurements, air photo interpretation, and field plot measurements needed to measure world forest resource conditions and
trends. Examples of this new approach are already appearing. This argument is addressed to members of the global forest policy
community concerned with assessment, and to scientists, technologists, and managers in the many technical fields already engaged
on one or another aspect of measuring and monitoring forest conditions at a national and regional scale. 相似文献
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Razieh Babapour Ismael Ghajar Reza Ghodsi 《Scandinavian Journal of Forest Research》2018,33(2):178-187
Earthwork operations accounted for great amount of forest road construction costs. Any Optimization in planning road profile needs a reliable objective function that calculates earthwork volume in an appropriate time and accuracy. This study aimed at incorporating the shape of the ground cross sections in calculating cut/fill areas using three alternative methods including: Multiple Linear Regression (MLR), Artificial Neural Network (ANN) and heuristic programming in MATLAB environment. The accuracy of results was validated via AutoCAD as a manual method for area calculation of road’s cross-section. Trapezoidal method applied to calculate the area of cut/fill in the heuristic method. Paired sample T-Test and statistical analysis (ANOVA) with confidence level of 0.95 indicated that the heuristic method not only reduced computing time but also provided accurate estimations as same as the manual AutoCAD based method. It can be concluded that although MLR and ANN estimations were as well as AutoCAD results within a reasonable time, they need to be retrained by adding, removing or changing entrance parameters. 相似文献
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四川省林学会建设长江上游生态屏障学术研讨会纪要 总被引：1，自引：0，他引：1
四川省林学会于 2 0 0 1年 1 2月 1 9日至 2 0日在四川农业大学举行了“建设长江上游生态屏障学术研讨会”。应邀参加研讨会的有四川农业大学、四川省林业科学研究院、四川省林业勘察设计研究院和四川省林业厅的专家、教授、研究员、高级工程师和从事管理工作的领导、部门负责人等共 3 0人。受四川省林学会理事长曹正其厅长的委托 ,副理事长、省林业厅副厅长杨冬生教授出席指导并作了学术报告。研讨会由学会秘书长张江陵高级工程师主持。四川农业大学为研讨会的顺利举办作了周详的安排。会议收到论文 1 9篇 ,有 1 5位专家发了言。大家围绕建… 相似文献
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To discuss the role of the gelatinous layer (G-layer) on the origins of the physical properties peculiar to the tension wood fiber (TW fiber), the deformation process of an isolated TW fiber caused by a certain biomechanical state change was formulated mathematically. The mechanical model used in the present formulation is a four-layered hollow cylinder having the compound middle lamella (CML), the outer layer of the secondary wall (S1) and its middle layer (S2), and the G-layer (G) as an innermost layer. In the formulation, the reinforced matrix mechanism was applied to represent the mechanical interaction between the cellulose microfibril (CMF) as a framework bundle and the amorphous substance as a matrix skeleton in each layer. The model formulated in the present study is thought to be useful to investigate the origins of extensive longitudinal drying shrinkage, large tensile growth stress, and a high axial elastic modulus, which are rheological properties peculiar to the TW. In this article, the detailed process of the mathematical formulation is described. In a subsequent article, some TW properties from a 70-year-old Kohauchiwakaede (Acer sieboldianum Miq.) will be analyzed using the newly developed model. 相似文献
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对岷江上游干旱河谷荒坡20个植物种群生态位进行了测定。结果表明:1)岷江上游干旱河谷主要植物种群生态位的测定以采用Simpson指数和重要值为宜,而生态位重叠则宜应用Pianka生态位重叠指数和综合优势比。2)垫状卷柏生态位宽度最大,它与高山韭、披针苔草、多茎景天、细柄草5个种群形成了共优群落。生态位宽度值分别为32.34,25.89,29.30,22.92和25.77。3)植物种群间有着较为普遍的生态位重叠但整体而言重叠值又比较小。植物生态位发生分离的程度还不够高,群落各种群间在竞争、互惠等种间相互作用上还没有达到较好的协调。 相似文献
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对已不能很好发挥农田防护作用的成过熟防护林,必须加快对其更新改造,才能保证农田防护林建设的质量和标准,充分发挥防护林的防护效益。北京市房山区对残破、病虫害严重的老龄防护林网更新改造过程中,在组织领导、管理机制、资金保障、科技支撑等方面,探索出一套农田防护林更新改造措施,确保了更新改造的顺利进行。 相似文献
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魏文彪 《绿色中国(A版)》2004,(9)
3月8日《钱江晚报》报道:因为“破烂王”的存在,杭州市一部分废旧物资得以回收再生;同样因为他们的存在,公共设施偷窃者有了稳定的“回收点”,去年杭州市仅失窃窨井盖就有1万多个……于是,出现了一种声音,认为杭州应提前一步行动,让“破烂王”下岗。 “破烂王”存在的不合理,其中之一就是破坏城市市容。认为“废品收购点、走街串巷收破烂的小车、着装邋遢的收废品人员,在一定程度上都是一个城市市容的伤疤。”收废品人员的形象确实难说是美的,与城市日新月异的市容的确形成了反差。但美与不美却是相对的。当人们想到一个人为了 相似文献