环境风作用下弧形立面机场航站楼自然排烟效果的数值模拟研究

机场航站楼公共区域多采用自然排烟方式,而环境风和排烟窗控制模式会影响排烟效果,尤其在弧形立面航站楼中影响效果显著。以某弧形立面航站楼为研究对象,选取候机指廊弧形区域的自然排烟窗分3段控制启闭,进而确定6种控制模式,采用 FDS火灾动力学模拟软件研究了不同模式下的排烟效果,获得了环境风和发烟量对危险到达时间的影响规律, 提出了排烟窗控制模式流程。结果表明:对于弧形立面航站楼而言,排烟窗分段控制模式下的排烟效果优于不分段控制模式,可以有效降低环境风对自然排烟的影响。当环境风速超过10 m/s时,须关闭迎风向排烟窗,避免烟气倒灌。在法向环境风作用的不利条件下,当发烟量在0. 05~0. 20之间时,危险到达时间的最大值tmax与发烟量x满足一次函数关系式:tmax=-3018x+1030.5。     

Movement distances enhance validity of predictive models

Including the distance species are able to move in predictive models improves conservation practice. Bird inventory projects carried out from 1993 to 2004 in Taiwan provide an opportunity to investigate the relationships among species distribution, movement distance, and the environment. We compared projected distributions of 17 Taiwanese endemic bird species using what we called the Standard Method (i.e. movement distance is zero) and what we called the Buffer Method (i.e. movement distance is longer than zero) in three presence-only models (GARP, MAXENT and LIVES). The Standard Method used species original occurrence records directly while the Buffer Method expanded the occurrence of species to areas 1 km² around each recorded location. We first tested the efficacy of the Buffer Method using ten common species of the 17, and then applied the method to two rare species of the 17. For both the common and rare species, the distributions predicted by the two methods showed slight but important differences. The Buffer Method for all species had a higher average predictive probability, while the Standard Method had a higher maximum predictive probability. Most of the values for the area under the curve (AUC) were over 0.8 with the exceptions of Taiwan Barbet (Megalaima nuchalis) and Taiwan Hwamei (Garrulax taewanus), which have recently separated from Indochinese Barbet (Megalaima annamensis) and Chinese Hwamei (Garrulax canorus), and since 2008 and 2006 have been regarded as species endemic to the study area. Kappa values showed good performance for all species using both methods. The Buffer Method, however, resulted in significantly higher sensitivity and accuracy values for all models of species (p < 0.05). We conclude that when modeling species distribution including the area where the species was censused along with areas within the minimum movement areas better defines the surrounding areas that might supplement core habitat requirements. Therefore, using the Buffer Method, species surrounding distribution can be obtained which provides a better understanding of the species distributions. Given that distribution size is a key to the conservation of species, we suggest the Buffer Method can be used in conservation planning.     

秦山岛周边海域大型底栖动物群落健康状况评价

2015年8月,对秦山岛周边的10个站位进行大型底栖动物定量调查。采用生物多样性指数法和丰度生物量比较法对大型底栖动物群落健康状况进行评价。结果显示,共鉴定大型底栖动物7大类31种,其中软体动物、环节动物各10种,节肢动物5种,脊索动物和棘皮动物各2种,纽虫类和腔肠动物各1种;密度优势类群为软体动物,占总密度的35.00%,生物量优势类群为脊索动物,占总生物量的49.35%;优势种分别为红狼牙虾虎鱼(Odontamblyopus rubicundus)、棘刺锚参(Protankyra bidentata)、内卷原盒螺(Eocylichna involuta)和微角齿口螺(Odostomia subangulata)。大型底栖动物密度为站位St.6最大,为115 ind./m²,St.2最小,为20 ind./m²,平均值为70 ind./m²;生物量St.3最大,为197.25 g/m²,St.9最小,为2.56 g/m²,平均值为54.04 g/m²。秦山岛受污染压力、人为活动干扰和生境限制能因素影响,多样性偏低,优势种为耐污的软体动物、脊索动物和棘皮动物,但其主要为K对策种类,大型底栖动物群落受到了轻度干扰,但群落结构仍较为稳定。     

沿空窄煤柱锚网带支护的巷道稳定性研究

锚杆支护是煤矿采准巷道的重要支护方式 ,沿空留巷技术是回采巷道支护技术改革的主要方面。笔者将两种技术相结合 ,用于保证回采巷道的稳定。在现场矿压观测的基础上 ,讨论了支承压力分布规律和窄煤柱护巷机理 ,运用极限平衡理论计算出护巷煤柱宽度 ,同时结合数值分析和现场巷道变形以观测结果 ,实践证明 ,只要设计参数合理 ,施工质量满足要求 ,沿空窄煤柱锚网带支护技术就可以保证回采巷道的稳定     

Stability and deformation of surrounding rock in pillarless gob-side entry retaining

We analyzed the stability of the retained gob-side entry in four different Chinese coal mining sites and evaluated the influencing factors of roadway deformation such as mining depth, support strength and area of gob-side hanging roof. It was found that the length of cantilever roof block above roadway has a major impact on the deformation, whereas the impact of mining depth is minor if the depth is less than 500 m. Minimum support resistance of 0.3 MPa is essential to effectively confine the deformation of a retained roadway. We performed physical experiments to further study the features of roof fracturing and their impact on roadway deformation under three typical immediate roof conditions, i.e., thick-immediate roof, thin-immediate roof and non-immediate roof. In addition, equations to calculate desired support resistance of filled gob-side wall were derived based on superimposed continuous laminate model. The results provide valuable theoretical and practical guidance for implementing pillarless gob-side entry retaining in engineering practices.     

石臼湖马鞍山环湖片区景观生态规划研究

环湖片区是人与自然亲密相处的空间场所,具有丰富的自然资源和人文资源。环湖片区的景观生态规划可以协调人与自然及资源利用的关系。对石臼湖马鞍山环湖片区的生态环境基底和生态敏感性进行分析,确定重点规划区域;采用相对重要性指数(d I)识别落在规划区域内的重要斑块;运用最小耗费距离模型(MCR)模拟潜在生态廊道,并将其与景观廊道、游憩廊道相叠加;构建连续的景观生态格局,为石臼湖马鞍山环湖片区的景观生态规划提供依据和指导。结果表明,以景观生态学原理为指导,用客观定量的标准对景观要素进行选择和规划,使景观中资源组合在结构和功能上接近或达到最优化,提高区域内景观的稳定性,可以实现对环湖片区生态环境的有效保护。     

Stability of workface using long-wall mining method in extremely thin and gently inclined iron mine

Long-wall mining method has its own advantages, such as small mining-cutting ratio, the simple technique of recovery and high level of mechanization, which is the optimal method used to mine gently inclined and extremely thin iron mine. How to ensure the safety of workers and equipment during mining is the key technical process. Based on elastic-plastic mechanics theory, the mechanic model of long-wall method mining gently inclined and extremely thin iron mine is established and the critical safety distance of workface is obtained. With the FLAC-2D simulation software, the rule of stress change, the deformation of workface and surrounding rock in different control-roof width are also summarized. The final results accord with the ones of theory test. We confirm the support-frame resistance of workface by analogy-statistic method. The results prove that hydraulic support-frame have the ability to provide enough pressure to assure the stability of working face within the 5-m of control-roof width.