山地条件多层建筑布局对风环境的影响效应

目的研究不同地形条件下多层建筑高宽比、布局方式等设计参数对风环境的影响效应。方法以计算机流体模拟软件Phoenics为工具,基于冬奥延庆赛区气候条件,调查与分析风环境的基本状况,并对多层行列建筑在地形条件为平地与坡地,高宽比为0.5、1、2,以及同一地形条件行列式、错列式、周边式的3种布局方式,共9种工况进行室外风环境模拟分析。结果建筑群处于坡地条件的风环境变化比平地条件更为多样;行列式布局的多层建筑高宽比与风环境效应的优劣存在空间差异性;坡地条件下围合式布局有效阻挡了冬季冷风的侵入,降低了围合空间内的风速与强度。结论不同地形条件的高宽比和布局方式对风环境影响效应显著,合理控制高宽比的取值范围,依据地形条件择优选择布局方式,促进自然通风、引导污染物扩散,创造舒适的建筑群空间环境,科学地开展山地条件的城市设计。

山地条件下索降灭火的优势及其作业要求

在分析了山地条件下采用直升飞机索降灭火较其他灭火方式相比所具有的优势的基础上,探讨了直升飞机索降灭火的作业要求。

山地条件下边坡稳定性分析及治理措施

就目前来看的话,很多位于山地的公路很容易出现一些滑坡灾害,给行车人员的生命以及财产安全造成了非常大的威胁。主要还是由于边坡的治理工作没有做到位,为了提高边坡的治理效率必须要对边坡的稳定性进行适当的分析,采取有效的策略提升边坡的治理效率,从而实现基础建设朝着更加安全以及环保的方向发展。本文对山地条件下边坡的稳定性进行了简单的分析,并且提出了相应的治理措施。

浅谈砂石山地加勒比松造林技术措施

用加勒比松复垦被破坏的砂石山地土地资源，是采砂区复垦种植发展的方向。要使加勒比松在植被破坏严重的砂石山地种植能速生丰产，就必须选择优质壮苗、用菌根土营养袋苗、适时适法、提前预整地、适时铲草、抚育、松土、施肥、做好病虫害的防治等合理经济的造林方式和抚育技术措施，加勒比松在砂石山地植被破坏严重的地方造林，就能有效改善砂石山地的立地条件。

Effect of Topography and Accessibility on Vegetation Dynamic Pattern in Mountain-hill Region

Knowledge of both vegetation distribution pattern and phenology changes is very important.Their complicated relationship with elevation and accessibility were explored through a geographically weighted regression(GWR) framework in Fujian province,China.The 16-day time series of 250 m Moderate Resolution Imaging Spectroradiometer(MODIS) Enhanced Vegetation Index(EVI) dataset from 2000 to 2010 was applied.Wavelet transform method was adopted to decompose the original time series and construct the annual maximum EVI and amplitude of the annual phenological cycle(EVI).Candidate explaining factors included topographic conditions,accessibility variables and proportions of primary vegetation types.Results revealed very strong positive influence from parameters of elevation and accessibility to big rivers and negative effect from accessibility to resident on both maximum EVI and phenological magnitude through ordinary linear least square(OLS) regression analysis.GWR analysis revealed that spatially,the parameters of topography and accessibility had a very complex relationship with both maximum EVI and phenology magnitude,as a result of the various combinations of environmental factors,vegetation composition and also intensive anthropogenic impact.Apart from the continuously increasing trend of phenology magnitude with increasing altitude,the influence of topography and accessibility on maximum EVI and phenological magnitude generally decreased,even from strongly positive to negative,with increasing altitude or distance.Specially,the most rapid change of correlation coefficient between them was observed within a low elevation or close distance;less variation was discovered within a certain range of medium altitude or distance and their relationship might change above this range.Non-stationary approaches are needed to better characterize the complex vegetation dynamic pattern in Mountain-hill Region.

Yanshan, Gaoshan-Two Active Volcanoes of the Volcanic Cluster in Arshan, Inner Mongolia

The volcanic cluster in Arshan, inner Mongolia, is located in the west of the middle section of the Da Hinggan Mountains. There are more than forty Cenozoic volcanoes among which the Yanshan Volcano and Gaoshan Volcano are the active ones in broad sense and basaltic central vents. Arshan is a newly found volcanic active region in the Chinese continent. The volcanoes are perfectly preserved and composed of cinder cones, pyroclastic sheets and lava flows. Their cones are grand and the Gaoshan cone is about 362m high, and the depth of the Yanshan crater is about 140m. The pyroclastic sheet is mainly made up of scoria, and the distribution area of scoria with thickness more than i m is about 27km^2 . There are two Carbonized-wood sites in the pyroclastic sheet and the ^14C datings indicate ages of 1990±100a B. P and 1900 ±70a B. P, which are rectified by dendrodating. Basaltic lava flows are uncovered, and they change from pahoehoe in the early stage to aa in the later stage. There are lots of perfect fumarolic cones, fumarolic dishes and lava tumulus in the front zones. The spread of lava flow is controlled by the local topography and its main body flowed northwestwards covering the Holocene rivers and swamp deposits and blocked up the Halahahe river and its branches to create six lava-dam lakes. For these distinguishing features, Arshan volcanic cluster could be called another natural “Volcano Museum”.

Geometrical and Geotechnical Characteristics of Landslides in Korea under Various Geological Conditions

The goal of this study is to determine the geometrical and geotechnical characteristics of landslides under various geological conditions using detailed field surveys, laboratory soil tests and precipitation records. Three study areas are selected to consider different rocks, including gneiss in Jangheung, granite in Sangju and sedimentary rocks in Pohang, South Korea. Many landslides have occurred in these three areas during the rainy season.Precipitation records indicate that landslides occurring in the gneiss area of Jangheung and granite area of Sangju may be influenced by the hourly rainfall intensity rather than cumulative rainfall.However, landslides occurring in the sedimentary rock area of Pohang may be influenced by hourly rainfall intensity and cumulative rainfall. To investigate the factors that influence these types of landslides, a detailed landslide survey was performed and a series of laboratory soil tests were conducted.According to the detailed field survey, most landslides occurred on the flanks of mountain slopes, and the slope inclination where they occurred mostly ranged from 26 to 30 degrees, regardless of the geological conditions. The landslide in the gneiss area of Jangheung is larger than the landslides in the granite area of Sangju and sedimentary rock area of Pohang.Particularly, the landslide in the sedimentary rock area is shorter and shallower than the landslides in the gneiss and granite areas. Thus, the shape and size of the landslide are clearly related to the geological conditions. According to the integrated soil property and landslide occurrence analyses results, the average dry unit weight of the soils from the landslide sites is smaller than that of the soils obtained from the nonlandslide site. The average coefficient of permeability of soils obtained from the landslide sites is greater than that of soils obtained from the non-landslide sites with the same geology. These results indicate that the soils from the landslide sites are more poorly graded or looser than the soils from the non-landslide sites.

Natural Hazard Preventinkon and the Mountain Land Risk Reduction in the Western Carpathians

The Western Carpathians are located out of world main natural hazardous zones. Human casualties are related more to snow avalanches in connection with mountain hiking, some individuals yearly by flooding and rarely by forest fires. Economic lost about 0.1 to 0.2 %, exceptionally up to 0.8 % of the gross domestic product (GDP) proportionally to the Carpathian regions of particular countries. Natural disasters are linked, except of the above mentioned events, to infrequent small and medium scale earthquakes, landslides, and erosion. Records of the most harmful natural events are found in archives since the 16th century. Their systematic study and factor analysis started from the end of the 19th century, and protective measures and organization of impact mitigation developed during the 20th century to minimize the risk.

Safety assessment of waste rock dump built on existing tailings ponds

The construction of waste rock dumps on existing tailing ponds has been put into practice in China to save precious land resources. This work focuses on the safety assessment of the Daheishan molybdenum mine waste rock dump under construction on two adjoining tailings ponds. The consolidation of the tailings foundation and the filling quality of the waste rock are investigated by the transient electromagnetic method through detecting water-rich areas and loose packing areas, from which, the depth of phreatic line is also estimated. With such information and the material parameters, the numerical method based on shear strength reduction is applied to analyzing the overall stability of the waste rock dump and the tailings ponds over a number of typical cross sections under both current and designed conditions, where the complex geological profiles exposed by site investigation are considered. Through numerical experiments, the influence of soft lenses in the tailings and possible loose packing areas in the waste rock is examined. Although large displacements may develop due to the soft tailings foundation, the results show that the waste rock dump satisfies the safety requirements under both present and designed conditions.