浅析钢筋混凝土箱涵施工技术

黑龙江省迎春林业局环城道路工程项目中有两座涵洞,通过地质勘查得出地基属于软土地基,所以在设计时采用钢筋混凝土箱涵结构。本文根据工程实例,简要阐述钢筋混凝土箱涵施工技术在工程项目中的应用。     

Forest road design with soil sediment evaluation using a high-resolution DEM

In this study, we combined a program to optimize forest road alignments with a method for prediction of surface erosion and related sediment delivered to streams. Combining the forest road design program with the high-resolution digital elevation model made it possible to estimate soil sediment based on a standard methodology, because a relatively accurate road prism could be generated. The combined program properly places and spaces drainage structures based on the Washington State Forest practice board manual. We applied the program to a part of Capitol State Forest in Washington State and optimized horizontal and vertical alignments while estimating movement of soil sediment from roads to streams. We discussed the effects of road surface materials, near-stream culvert distance to stream, and out-sloped forest road template on total road costs and soil sediment delivered to streams. Using lower quality rock surfacing reduced total costs, but the amount of soil sediment from lower quality rock surfacing was 1.5 times more than that on a higher quality rock traction surface. Therefore, lower quality rock surfacing should not be used near the stream. The placement of near-stream culverts 15 m upstream and out-sloped road template were examined using a traction surface on 15-m sections upstream and lower quality rock surfacing on other sections in order to reduce soil sediments to the stream and total costs. As a result, placing near-stream culverts 15 m upstream and using an out-sloped road template significantly reduced total road cost and soil sediment. Finally, we optimized horizontal and vertical alignments while limiting soil sediment to a specified maximum level. The model successfully optimized forest road alignments, which reduced total road cost as well as soil sediment.     

波纹钢管涵洞在公路工程中的应用研究

通过对公路涵洞的常见破坏原因的分析,说明了多年来一直使用的钢筋混凝土圆管涵存在的一些问题。提出用波纹钢管涵代替钢筋混凝土圆管涵是解决这些问题的途径。简要介绍波纹钢圆管涵的基本知识,以及波纹钢管涵洞的施工过程。     

林区公路小桥涵位置与型式的选择

本文主要介绍林区公路小桥涵位置确定的原则、步骤及位置的测量;小桥涵型式选择的决定因素。     

Effect of gap size on mid-rotation stand structure and species composition in a naturally regenerated mixed broadleaf forest

This paper is an assessment of the effect of gap size on stand structure and species composition 48 years following treatment in a mixed broadleaf upland forest. Established in 1960, the study tests three circular openings, 15.2 m (0.02 ha), 45.7 m (0.16 ha), and 76.2 m (0.46 ha). Forty-eight years following treatment (2008) basal area, top height, and quadratic mean diameter were significantly lower in 15.2 m openings. Maple (Acer spp.) species had the highest mean importance value across treatments (0.40). Trends suggest that species composition of dominant and codominant trees among opening sizes may have been influenced by shade tolerance adaptations of the species groups present. Whereas 15.2 m openings were dominated by shade tolerant maple species, 45.7 and 76.2 m openings produced a mixture of commercial species including shade intolerant species such as yellow-poplar (Liriodendron tulipifera L.), trees of intermediate shade tolerance like oak (Quercus spp.), and shade tolerant maple. Data further suggest the density of overstory oak was highest in the intermediate opening size (45.7 m), while yellow-poplar increased in the larger opening sizes. Evaluation of species shifts between 1981 and 2008 showed that relative basal area of maple increased across all treatments. Relative basal areas from 45.7 to 76.2 m openings suggest declines in yellow-poplar and other non-commercial species were balanced by increases in oak and maple.     

林区公路干砌涵石盖板的实践

东方红平沙公路，通过跨径为0.8m、1．0m、1.2m共32座涵洞的工程实践证明，干砌涵结构在林区公路中具有造价低、工期短、施工简便、宜在盛产石材地区推广应用。     

孟连县南垒河天然渔业资源自然繁殖保护区鱼类多样性调查研究

于2018年10月至11月以系统抽样的方式,设置6个调查断面,结合走访和查阅相关文献资料,对孟连县南垒河天然渔业资源自然繁殖保护区鱼类资源开展调查。经过分析、鉴定,结果表明:保护区分布有鱼类40种,隶属于4目13科35属,鱼类组成以鲤形目为主,共有27种,其中外来鱼类9种,占总种数的22.5%;保护区鱼类栖息习性有急流型类群、流水型类群、静缓流型类群,繁殖习性分为产沉性卵、漂流性卵、强粘性卵、特殊产卵类型鱼类,食性有以着生藻类、水生昆虫或其它底栖无脊椎动物、浮游生物及其它以肉类为食的鱼类;保护区鱼类无典型的洄游活动,但部分鱼类繁殖时有短距离溯河上行的习惯。文中就人类活动对保护区鱼类多样性的影响进行讨论,提出建立健全管理机构、提高管理人员业务素质,增加资金投入,加强宣传、增强公众保护意识等加强保护区建设与管理的建议。     

钢筋混凝土圆管涵受力破坏实验研究

钢筋混凝土圆管涵是公路设施的一个重要结构物,对三个圆管涵样本进行实验并结合有限元分析,详细研究了圆管涵的开裂荷载、荷载-挠度关系等力学特性,得出圆管涵开裂荷载约为50 kN/m。圆管涵在外力作用下,开始时随着荷载的增加,挠度逐渐增加,荷载-挠度呈线性关系,当荷载达到一定值后,再继续增加荷载,挠度迅速增加直至圆管涵破坏。涵管端部的竖向变形比涵管中部的变形大,涵管中部的横向变形比涵管端部的变形大,涵管竖向变形比横向变形大。涵管顶部和底部的内壁几乎同时开裂,但管顶裂缝宽度比管底发展快,内壁裂缝较少。外壁侧面比内壁开裂要晚,裂缝较多,分布较广,裂缝宽度发展缓慢,没有明显的主裂缝。涵管结构设计时裂缝控制应以内壁的裂缝为主。     

Response to canopy opening does not act as a filter to Fagus sylvatica and Acer sp. advance regeneration in a mixed temperate forest

? In mixed-species forest stands, large losses in tree species diversity often occur during the regeneration phase. In a former coppice-with-standards, we investigated whether the limiting stage in the recruitment process of advance regeneration is the immediate seedling response to canopy release. Experimental canopy gaps were opened and the survival and growth of advance seedlings (Fagus sylvatica, Acer pseudoplatanus, Acer campestre, Acer platanoides) growing in the gaps or under closed canopy were monitored for three years.

? All species responded positively and rapidly to canopy release. Survival was not affected by gap opening. Diameter increment after gap opening was similar across species, and height increment was greater for Acer platanoides and for Acer pseudoplatanus. Post-release diameter and height growth were mainly determined by pre-release seedling size. Competition from neighbouring seedlings did not affect growth in the three years following canopy opening.

? In the recruitment process of F. sylvatica and Acer sp. advance regeneration, the recovery from canopy release did not appear as a limiting step that would filter against some species. Pre-release size was the main factor accounting for post-release growth and is probably a major determinant of long-term seedling dominance.

     

浅谈高等级公路中涵洞的勘测设计

公路的病害大部分是由水害引起的,针对高等级公路常见的水害问题,提出通过合理的涵洞布设和完善的引、排水系统加以解决;通过介绍涵洞外业勘测应注意的问题、涵洞流量计算、孔径和形式选择、进出水口的处理,阐述如何进行涵洞勘测设计,做到即安全可靠、经济实用、方便施工,又能满足排水要求。     

谈林区公路中涵洞位置的设计

本对林区公路涵洞位置提出了几种设计方法。即（１）逢沟设涵;（２）改移河槽;（３）截弯曲直;（４）特殊情况下的涵洞设计。     

福建气候条件下月季切花栽培技术

从品种选择、优质壮苗培育、越夏栽培、修剪和花期调节等方面系统地介绍了在福建气候条件下的月季丰产栽培技术。     

武汉上涉湖湿地自然保护区生物资源现状及评价

2006年7月～2007年2月对武汉上涉湖湿地自然保护区动植物资源进行了调查,结果表明：保护区有维管束植物581种,其中种子植物556种;植被有5个植被亚型,20个群系．底栖动物29种,鱼类74种,其中省级保护鱼类2种．湿地兽类6目9科23种,其中国家二级保护种类1种,省级保护种类4种;湿地鸟类111种,其中国家重点保护种类一级3种,二级8种,省级保护种类36种;被列入国际贸易公约鸟类15种,被列入中国濒危动物红皮书的鸟类6种,被列入“中日候鸟协定”鸟类47种,被列入“中澳候鸟协定”14种,“三有鸟类”86种．认为上涉湖湿地自然保护区生态系统完整、自然,生物多样性丰富,物种珍稀特有,符合国家重要湿地标准．     

泸沽湖省级自然保护区鱼类物种多样性调查研究

为对泸沽湖省级自然保护区的生物多样性及环境质量做出更好的评估,分别于2016年3月,6月,7月就其鱼类资源特点及其分布格局等开展了3次调查。结果表明,泸沽湖省级自然保护区记录鱼类6目8科15属17种,鲤形目鲤科鱼类种数最为丰富,共9种,占泸沽湖鱼类总种数的52.9%;土著鱼类仅2属4种,分别为泥鳅、厚唇裂腹鱼、宁蒗裂腹鱼、小口裂腹鱼。区系组成与云贵高原湖泊存在共同特点:种类贫乏,个体较小,生长稍慢。泸沽湖鱼类物种多样性匮乏、物种同域分化现象明显、鱼类特有性极强、物种群落脆弱性极高、物种组成自然性偏低。文中提出保护好鱼类产卵场,加强入湖河流的清淤治理,建立保育繁殖基地等保护策略。     

湖南康龙自然保护区鱼类资源调查

2007年6—7月、2010年8—9月两次对康龙自然保护区境内鱼类资源进行调查,利用网捕法和电捕法共采集到鱼类标本2000号,经鉴定共发现鱼类37种,隶属4目,10科。其中鲤形目2科27种,占73%,鲈形目5科7种,占18.9%,鲶形目2科2种,占5.4%,合鳃鱼目1科1种,占2.7%,调查发现康龙自然保护区的鱼类区系,具有较强的华东区系和华南区系双重特征,该区经济鱼类种类丰富,但是鱼类小型化、低龄化趋势显著,且出现衰退现象,鱼类资源需要加强保护。     

连云港盐滩地绿化施工技术应用与分析

在连云港盐滩地绿化施工过程中,采用铺设暗渠和客土回填等工程措施以及强化适生树种选择、提高种植技术水平和加强养护管理等技术措施,栽植各类绿化植物29种,结果表明平均成活率达93.26%,其中22种生长状况优良,表现出较强的适应性。     

箱涵进海路结构的设计研究

箱涵进海路结构是一种适用于软土海底地基上的轻型海上路基结构,具有承载能力较好,施工方便快捷的特点。本文结合埕海油田张东开发海工工程,对箱涵进海路结构的抗滑、抗波浪浮托、抗倾稳定稳定进行了计算,计算结果表明箱涵进海路结构的稳定满足要求,为箱涵进海路结构的应用提供了理论上的保证。     

南滚河国家级自然保护区的动物多样性

基于系统的植物学和动物学调查和分类学研究,以及乡土知识在生物多样性的利用和保护方面的应用,对分布于保护区的哺乳动物的科和种、鸟类的分布类型和生境分布、两栖和爬行动物的区系、鱼类的类型和特点作了调查分析,讨论了分布于保护区的陆生和水生动物、动物的生态系统和多样性特征。结果表明:保护区的动物多样性极为丰富,有98种哺乳动物分布,隶属于10个目30个科75个属,占全国哺乳动物种类数的16.14%和云南的32.23%;有145种鸟类分布,隶属于13个目36科,占全省鸟类种数的17.4%;有26种(亚种)两栖动物,有39种(亚种)爬行动物;根据不同的栖息地、水流类型、摄食习性,可将保护区的鱼类分别划分为3类、2类、3类,并介绍了该地区鱼类的特点。分析了该地区的生物地理群落多样性的特点,指出了保护区管理中存在的问题,制定了长期发展目标,为今后的管理提出了建议。     

湖南书院洲国家湿地公园鱼类资源调查

通过对湖南书院洲国家湿地公园两个不同断面鱼类进行了连续监测,对其群落组成、生物多样性、优势种组成进行了比较分析。调查发现:有鱼类30种,隶属于5目9科。两个不同生境断面的鱼类小型鱼类均以鲤形目鲤科鱼类为主,且多为小型鱼类。在鱼类的群落结构多样性度量值差异不大:(1)断面Ⅰ鱼类分5目7科22种;断面Ⅱ有鱼类分4目7科19种;(2)断面Ⅰ和断面Ⅱ的多样性指数分别是2.58和2.67,均衡度指数是0.835和1.1,种类相似性指数是53.7%。本次调查还发现湿地公园鲤形目鲤科鱼类新记录5种:分别是银鮈、似鮈、达式鲌、飘鱼和红唇薄鳅。     

公路桥涵汽车用电子限高报警系统（Ⅰ）——电子限高报警装置的原理与基本要求

公路桥涵车用电子限高报警装置,是一种防止超高车辆撞坏桥涵的自动检测报警装置。文中描述这种专用电子限高装置的工作原理、基本要求以及常用的激光检测器与红外检测器的性能,为下一步进行设计公路桥涵车用电子限高报警装置提供必要的理论依据。