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1.
The increased numbers of vehicles using roads in the world today are cause of traffic-related problems, and in this respect, road traffic accidents are an important topic relating to public health. Especially on the road connecting two border provinces, traffic accidents are increasing substantially in parallel with the quantity of transport facilities. By determining areas where traffic accidents result in deaths or injuries, accident prevention strategies can be developed. This study applies the spatial statistics techniques using Geographical Information Systems (GIS) to determine the intensity of traffic accidents (hot-spot regions) over 45 km of main routes in Rize Province, Turkey. Traffic accidents recorded in data spanning 5 years are combined with a geographical dataset for evaluation using hot spot statistical analysis. Unlike other studies, this study used hot spot analysis based on network spatial weights (an innovative review in the methods of determining traffic accident hot spots: “novel application of GIScience”) to identify black spots for traffic safety. To perform the analysis using Hot Spot Analysis: Getis-Ord Gi*, a generated network dataset and the spatial weights of the road data are used to generate network spatial weights. Then, Kernel Density method is used to define traffic accident black spots. Finally, these two methods are compared each other with visually.  相似文献   

2.
小卡子隧道是连接九龙县城和石棉县城的一条便利通道,它是连接S215和S211的绿色保障,九龙和石棉之间是海拔高度4 000 m以上,九龙县城周边为高原宽谷丘陵地区,地势起伏较大。九龙至周边沿线不良地质和特殊褶皱构造发育,其中冰雪害几乎每年冬春都发生,且影响线路较长,其它地质灾害也时常暴发,致使交通事故频繁发生,成为制约九龙县发展,因而急需要对线路进行改造,拟建连接九龙县至石棉县小卡子隧道即为公路改建工程。  相似文献   

3.
In order to investigate the mechanism of the long-term settlement of road on the soft soil, an in situ measurement of a highway in southeast China was conducted during both the construction and post-construction stage. In the theoretical analysis, the long-term settlement of the pavement on thick soft soils was divided into three main components: the consolidation settlement, the creep deformation and the traffic load-induced deformation. The equivalent time line model based on the viscous–elastic–plastic theory was adopted to simulate the road settlement caused by the consolidation and creep of the subsoil. A cyclic strain accumulation model, which was obtained from laboratory tests of soil elements, was adopted to consider the road settlement induced by cyclic traffic loadings. A pavement dynamic response model was used to calculate the dynamic stresses in the subsoil generated by moving traffic loads when the road was open to service. It was found that the equivalent time line model combined with the cyclic strain accumulation model could predict the road settlement accurately at both the construction and post-construction stage. Numerical results showed that the traffic speed had limited effect on the post-construction road settlements for the speed range considered. The post-construction settlement of the road, mainly composed of the traffic-induced settlement and soil creep deformation, could be reduced significantly by increasing the embankment surcharge during the construction stage. The creep component accounted for over 10% of the total post-construction settlement, while the percentage of the creep deformation in total post-construction settlement decreased rapidly as the embankment surcharge increased.  相似文献   

4.
Tsunami evacuation planning in coastal communities is typically focused on local events where at-risk individuals must move on foot in a matter of minutes to safety. Less attention has been placed on distant tsunamis, where evacuations unfold over several hours, are often dominated by vehicle use and are managed by public safety officials. Traditional traffic simulation models focus on estimating clearance times but often overlook the influence of varying population demand, alternative modes, background traffic, shadow evacuation, and traffic management alternatives. These factors are especially important for island communities with limited egress options to safety. We use the coastal community of Balboa Island, California (USA), as a case study to explore the range of potential clearance times prior to wave arrival for a distant tsunami scenario. We use a first-in–first-out queuing simulation environment to estimate variations in clearance times, given varying assumptions of the evacuating population (demand) and the road network over which they evacuate (supply). Results suggest clearance times are less than wave arrival times for a distant tsunami, except when we assume maximum vehicle usage for residents, employees, and tourists for a weekend scenario. A two-lane bridge to the mainland was the primary traffic bottleneck, thereby minimizing the effect of departure times, shadow evacuations, background traffic, boat-based evacuations, and traffic light timing on overall community clearance time. Reducing vehicular demand generally reduced clearance time, whereas improvements to road capacity had mixed results. Finally, failure to recognize non-residential employee and tourist populations in the vehicle demand substantially underestimated clearance time.  相似文献   

5.
Providing safety in roads for the purpose of protecting human assets and preventing social and economic losses resulted from road accidents is a significant issue. Identifying the traffic hot spots of the roads provides the possibility of promoting the road safety which is also related to investigate frequency and intensity of occurred accidents. Accidents are multidimensional and complicated events. Identifying the accident factors is based on applying a comprehensive and integrated system for making decisions. Therefore, applying common mathematical and statistical methods in this field can be resulted in some problems. Hence, the new research methods with abilities to infer meaning from complicated and ambiguous data seem useful. Therefore, along with identifying the traffic hot spots, adaptive Neuro-Fuzzy inference system is used to predict traffic hot spots on rural roads. In this process, a fuzzy inference system from Sugeno type is trained applying hybrid optimization routine (back propagation algorithm in combination with a least square type of method) and accident data of Karaj-Chalus road in Tehran Province. Then the system was tested by a complete set of data. Finally, the stated system could predict 96.85 % of accident frequencies in the studied blocks. Furthermore, the amount of effective false negative in all cases included only 0.82 % of predictions, which indicated a good approximation of predictions and model credibility.  相似文献   

6.
道面结冰是北京地区高速公路交通安全的主要危害因素。利用北京地区2008-2015年28个ROSA交通气象站的结冰数据分析了北京地区高速公路道面结冰的基本特征。结果表明:(1)北京市高速公路道面结冰空间差异显著,不同高速公路结冰特征显著不同,同一高速公路不同路段结冰特征也明显不同,这与高速公路各路段局地气候存在差异有关。(2)道面结冰主要发生在北部和东部高速公路所在路段,以小汤山西桥站、顾家庄桥站、六道口桥站和丁各庄桥站道面结冰灾害最为严重。冬季道面结冰月变化显著,11月和3月,结冰次数较少,结冰持续时间短;12月、1月和2月结冰次数多,结冰持续时间长。(3)持续时间越长的结冰过程结冰次数越少。不同持续时间的结冰过程在各时段的结冰次数和累积结冰时长均存在明显差异,两者在各时刻的演变特征基本相同,峰值均出现在22:00,且在00:00之后呈明显减少趋势。(4)大部分站点慢车道比快车道更容易结冰,少部分站点快、慢车道结冰率近似,有的站点甚至快车道结冰率远高于慢车道。快、慢车道水或覆盖物厚度与交通站点所处位置的局地气象条件密切相关。(5)气温、道面温度和大地温度与水或覆盖物的厚度变化呈反相位,即温度越低,水或覆盖物的厚度越大。这可为北京地区道面结冰预报预警方法的开展提供着眼点和依据。  相似文献   

7.
The earthquake is known to be an unpredictable geophysical phenomenon. Only few seismic indicators and assumptions of earthquakes can be predicted with probable certainty. This study attempts to analyze the earthquakes over the Indo-Himalayan Border region including Bhutan, Bangladesh, Nepal, China and India during the period from 1995 to 2015. Bangladesh, Bhutan and China borders experience fewer earthquakes than Nepal and India border regions. However, Indo-China rim has inconsistency and vast range in its magnitude. Bangladesh though is a small country with respect to others, but it experiences earthquakes comparable to Bhutan. Nepal experiences highest number of earthquakes. In the last 20 years around 800 records have been observed with moment magnitude > 4.0 Richter scale, while very few records (around 10–12) have been observed for large earthquakes having moment magnitude > 6.0 Richter scale over the region. In this study adaptive neuro-fuzzy inference system has been implemented to assess the predictability of seismic moment associated with large earthquakes having the moment magnitude between 6.0 and 8.0 Richter scales using different combination of epochs, technique and membership functions. The Gaussian membership function with hybrid technique and 40 epochs is observed to be the reasonable model on the basis of the selected spatial and temporal scale. The forecast error in terms of root-mean-square error with the stopping criterion 0.001 has been observed to be 0.006 in case of large earthquakes (> 6.5 Richter scale), that is, forecast accuracy of 99.4%. The model bias of 0.6% may be due to inadequate number of large earthquakes having moment magnitude > 6.5 Richter scale over the region.  相似文献   

8.
This paper examines the hyperspectral signatures (in the visible near-infrared (VNIR)–shortwave infrared (SWIR) regions) of different samples of sandy soils possessing varying grain size and water content. Ten samples of sandy soils with differing textures and water contents were examined using a hyperspectral radiometer operating in the 350–2,500-nm range, and the spectral curves were obtained. Analyses of the curves indicate that grain size of sand has a considerable influence on the spectral response in the visible, NIR and SWIR regions, i.e. there is a decrease in the overall reflectance with increase in grain size. While the 350–575-nm region exhibits maximum overlap of spectral reflectance and, hence, least spectral separability between the soil types, the 2,000–2,100-nm region exhibits highest spectral separability between the sand samples of different textures. As regards the water content, it is seen that overall reflectance increases with decreasing water content in the sample, especially in the 1,400–1,800-nm regions. Further, the slope of the curves in the 1,890–2,100-nm region shows a well-defined relationship with the water content. Based on these well-defined relations, it is inferred that hyperspectral radiometry in the VNIR and SWIR regions can be used to estimate the texture and water content of sandy soils.  相似文献   

9.
喜马拉雅北部地区春季大气特征及日变化分析   总被引:1,自引:1,他引:0  
利用珠峰北部地区的观测资料和AIRS卫星遥感资料,分析了喜马拉雅北部地区的大气日变化及其垂直结构.结果发现喜马拉雅北部地区气温日变化具有明显的单峰单谷型特征,一天气温最高值出现在18:00左右,最低值出现在早上7:00~9:00.风速的日变化呈现单峰型特征.气压的平均日变化呈双峰双谷型分布特征,气压极大值出现在2:00和12:00,气压极小值出现在6:00和19:00时,其中19:00出现气压最小值.感热通量、潜热通量的平均日变化和气温日变化具有一致性,春季感热通量大于潜热通量.净辐射通量的日变化特征是单峰型特征,每日最大值出现的时间比感热通量及潜热通量的最大值出现的时间早2个小时.引起高原地区日变化剧烈有2个主要原因:一是高原地区大气柱的质量较小,对太阳辐射的削弱较小,且相同的辐射加热和冷却可使较少大气产生较大温度变化;二是高原地区是大气云光学厚度较小的区域,由此可使地面在日间接受较强烈的太阳短波辐射而增温较大,在夜间又接受较小的大气长波逆辐射而降温较大.  相似文献   

10.
天山公路由于其特殊的复杂地形、地质条件及降雨等因素,严重影响其正常通行.因此,借助于GIS新技术手段优势,建立一套适合于天山公路特殊区域的评价决策支持系统,就显得尤其重要.天山公路地质灾害评价与决策支持信息系统的建立,首先在详细分析天山公路地质病害原理的基础上,收集公路沿线已有的基础地理、地学等资料,对照实地工作成果和遥感成果,结合数据库及遥感图像处理技术,按数据库规则进行相应的综合、整理、筛选、归纳及转换,建立以ArcGIS为数据平台的多源信息数据库.然后基于ArcEngine平台,开发一套集基础数据的采集、存储、管理、检索、图形编辑、空间模型分析、线路区域稳定性评价、公路地质选线,以及三维可视化飞行成果图形生成及输出为一体的地质灾害评价与决策支持信息系统操作应用平台.系统整合不同类型的数据资料和多媒体信息,实现了基于三维的空间信息查询和分析功能,势必为国土资源和交通建设管理部门提供一种可靠的决策管理应用平台.  相似文献   

11.
Thermal infrared remote sensing technology based on unmanned aerial vehicle (UAV) was applied to estimate the spatial distribution of ground surface temperatures on permafrost slopes and evaluate the thermal influence of nearby engineering infrastructure. This paper presents a method that uses a miniature UAV with a thermal infrared sensor to collect thermal images with high temporal–spatial resolution. Moreover, spatial analysis is used to effectively evaluate the relationship between engineering infrastructure and permafrost slopes in the Qinghai–Tibet Engineering Corridor (QTEC), China. To test the method, aerial measurements were collected from 11:00 to 17:00 in July and August of 2017 at two permafrost slopes along the QTEC, where the Qinghai–Tibet Highway (QTH), Qinghai–Tibet Railway (QTR), and electric towers were built on permafrost slopes. The differences of ground surface temperature between the highway and the surrounding soil were largest at 11:00 and 17:00; the differences were smaller at noon to approximately 15:00 when the difference was minimal, and the differences began to increase after 15:00. The distances of the thermal influence of the highway, railway, and electric towers on the surrounding permafrost slopes are approximately 12–14, 8–10, and 2–4 m, respectively. The results indicate that the degree of influence of engineering structures on permafrost slopes is as follows: QTH?>?QTR?>?electric towers. This study is the first to use UAV-based thermal infrared remote sensing to evaluate the thermal dynamics of permafrost slopes along the QTEC. These results may provide new insights into the future design, construction, and maintenance of engineering structures on permafrost slopes.  相似文献   

12.
The present study aims to compute the temporal and spatial distribution of road traffic induced noise pollution in an urban environment by monitoring and mapping. The study area was the entire Asansol city of West Bengal, India. A total of 35 locations were selected for collection of data, classified as industrial, commercial, residential, sensitive and mixed areas according to the national regulatory standards. Noise recordings were conducted during morning and night hours. Day time Leq level ranged between 51.2 and 89.0 dB(A), whereas it ranged between 43.5 and 81.9 dB(A) during night. The average Ldn value was 73.28 ±8.51 dB(A) (Range: 55.1–87.3); The traffic noise index was 80.62 ± 15.88 dB(A) (Range: 49.4–115.8). The computed data were mapped by utilization of Geographic information system methodology that allowed the visualization and identification of the extent and distribution of sound pollution across the study area. This proves to be an ideal tool for carrying out noise impact assessments in urban settings. The study reveals that present noise level in all the locations exceeds the prescribed limit. Based on the finding, it can be mentioned that the population in this industrial town are exposed to significantly high noise level, which is caused mostly due to road traffic. The study reveals that vulnerable establishments like schools and hospitals are subjected to significantly high noise level throughout the day and immediate mitigatory measures are required to alleviate the problem.  相似文献   

13.
Quantitative evaluations of the impact of groundwater abstraction on recharge are rare. Over a period (1975??007) during which groundwater abstraction increased dramatically in the Bengal Basin, changes in net groundwater recharge in Bangladesh are assessed using the water-table fluctuation method. Mean annual groundwater recharge is shown to be higher (300??00?mm) in northwestern and southwestern areas of Bangladesh than in southeastern and northeastern regions (<100?mm) where rainfall and potential recharge are greater. Net recharge in many parts of Bangladesh has increased substantially (5??5?mm/year between 1985 and 2007) in response to increased groundwater abstraction for irrigation and urban water supplies. In contrast, net recharge has slightly decreased (??.5 to ???mm/year) in areas where groundwater-fed irrigation is low (<30% of total irrigation) and where abstraction has either decreased or remained unchanged over the period of 1985??007. The spatio-temporal dynamics of recharge in Bangladesh illustrate the fundamental flaw in definitions of “safe yield??based on recharge estimated under static (non-pumping) conditions and reveal the areas where (1) further groundwater abstraction may increase actual recharge to the shallow aquifer, and (2) current groundwater abstraction for irrigation and urban water supplies is unsustainable.  相似文献   

14.
Along with climate change, cloud-to-ground lightning (CG)-caused forest fires are becoming increasingly pronounced. This study employed the Chinese lightning location system data (2009–2015) and worldwide lightning location network data (2005–2015) to jointly analyze CG characteristics and study the correlation between CG and climate change. The Muli county in southwest China was taken as research area. The CG number showed a clear increasing trend on yearly timescale. At the monthly timescale, CG occurred from March to October, with a peak in June. At the daily timescale, 15:00–23:00 (local time) and 00:00–05:00 both had a high CG frequency, and the peak was at 18:00–19:00. We divided CG electric current intensity into six grades and found that negative CG accounted for more than 90% of total CG and, among these, the 3rd and 4th intensity grades accounted for about 70%. To examine the spatial distribution, we focused on lightning-caused forest fires high occurrence seasons. In spring, CG distribution changed from the initial southeast to the northwest, gradually spreading to the whole area of Muli, whereas the CG area gradually moved back to the southeast in autumn. Our research suggested that minimum temperature was the most sensitive temperature to CG change. In March, the relationship between CG and minimum temperature showed a strong positive correlation. Considered jointly, we suggest the CG and related lightning-caused forest fires could increase in the future under an increased minimum temperature and decreased precipitation, especially in March.  相似文献   

15.
Due to increasing motorization, construction of flyovers and growth in transport network, the noise level has exceeded the prescribed limits in many Indian cities. The health implications of high noise levels are being identified as hypertension, sleeplessness, mental stress, etc. Due to this adverse effect of noise level, it is essential to assess the impact of traffic noise on residents and road users. This research is an effort to quantify and analyze the traffic noise emissions along bus rapid transit corridor in Delhi. Field measurements were carried out to understand and assess various aspects of the impact of bus rapid transit system corridor on land use and social lives of residents and road users. The present analysis presents the comparison between observed and predicted noise level at selected corridors and also describes the mitigatory measures to overcome such type of traffic noise pollution through design of noise barrier along the road and motivate people towards the use of public transport system.  相似文献   

16.
Road dust samples were collected from four different areas having different landuse patterns: industrial, heavy traffic, residential and mixed use in Delhi city of India. The samples were analyzed for Ba, Co, Cr, Cu Fe, Mn, Ni, Pb and Zn by ICP-AES. Results indicate high levels of Co, Cr, Cu, Mn and Ni in samples collected from industrial area. Ba, Pb and Zn showed higher concentration levels in heavy traffic area while Fe did not show any discernible variation between the localities. The concentrations of Fe, Mn, Ba, Zn, Cr, Cu, Pb, Ni and Co showed a decreasing trend. The content of heavy metals was comparable to those in other cities in the world. A multivariate statistical approach which includes Pearson’s correlations and principal component analysis was used to identify the possible sources of metals in the road dust. Enrichment factors were estimated for further confirming the sources of contamination. Significant positively correlations between road dust metals Cu–Mn–Co–Cr–Ni suggest that major common source of origin is industrial activities. A meaningful correlation between Ba and Zn, and a moderate positive correlation between Pb and Ba indicate the influence of traffic activities. Enrichment factors calculation indicated that Pb, Cu, Cr and Zn are moderately enriched whereas Co, Ni and Mn are less enriched while Ba exhibited very low enrichment in the dust samples. The results indicate that industrial and vehicular traffic are the two major sources. Traffic appears to be responsible for the high levels of Zn, Cu and Ba. High concentration of Co, Cr, Cu and Mn may be due to industrial sources.  相似文献   

17.
High homicide rates constitute a major public health problem in the United States. In the South high rates have been historically conspicuous, and have contributed to the elevated level in the U.S. compared to other countries at a comparable stage of development. This research illustrates the historical persistence of homicide in the South and presents a regionalization of U.S. states based on their quinquennial homicide profiles since 1935. Several social indicators are plotted against trends in lethal violence for the homicide regions. The analysis suggests a pattern of rates declining away from a core region in Alabama and Georgia, and some convergence between the high rates of the South and the increasing rates of other regions. Southern homicide rates remain high in spite of suggestions that cultural differences between the South and other regions have eroded to insignificance.  相似文献   

18.

Waterlogging (WL) refers to the process by which water flow is resisted in vertical and horizontal directions and thus water stagnates for a short or long span of time; it is induced by a combination of human and natural factors. In the southwestern region of Bangladesh, including Natore District, WL is a significant issue that needs to be addressed if agricultural activity is to be successful. This study aimed to identify surface WL in Natore District and to characterise the WL scenario in the study area in terms of hydrogeology. Waterlogged areas were identified with a geographic information system using satellite images corresponding to the premonsoon and postmonsoon periods. Using groundwater level data (1990–2017), the pre- and postmonsoon scenarios of the waterlogged areas were indicated by seasonal and perennial types of WL. Groundwater recharge scenarios were classified as long and short lag times. Most of the study area was characterised by thick clay or silty clay surficial layers with low water penetration rates, resulting from low porosity and low hydraulic conductivity. The cross-correlation between rainfall and groundwater level revealed the response of groundwater to rainfall, with a lag time of 1–5 months. Long lag time areas exhibited slow groundwater recharge and significant groundwater level fluctuation, with lower hydraulic conductivity values of 49.37–76.24 m/day. In contrast, short lag time areas displayed rapid groundwater recharge and small groundwater fluctuation due to a good proportional relationship with rainfall and higher hydraulic conductivity values of 74.74–117.79 m/day.

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19.
魏佳北 《冰川冻土》2022,44(6):1887-1897
Snowdrift is one of the most typical snow disaster forms of road traffic in Xinjiang area. Its impact on road traffic is mainly reflected in reducing driving visibility and causing traffic interruption induced by a large amount of snow on the road surface. The snowdrift disaster along the road in Xinjiang area shows the characteristics as many points,long lines and wide spread occurring with uneven distribution in time and space. Snowdrift question involves wind field,snow distribution field,temperature field and humidity field coupling,which is a very complex scientific problem. At the same time,the prevention and control of snowdrift disasters is also a practical problem that needs to be solved urgently in the construction and operation of road traffic infrastructure in cold areas. For expressways in areas of frequent snowdrift occurring,its snowdrift disaster caused by the w-beam barrier is becoming more and more obviously. But there is still a lack of in-depth research on the w-beam barrier,which is one kind of auxiliary facilities of the highway deepening the snowdrift disaster. In view of the status mentioned above and in order to explore the causes and prevention methods to snowdrift disaster by w-beam barrier,on the background of Beijing-Urumqi Expressway(G7)engineering,the field model tests of the w-beam barrier,the cable barrier and the no barrier embankment were designed. The study also combined with numerical simulation and highway field investigation and other methods in order to verify each other. In the meantime,the influence of the w-beam barrier and cable barrier on the road snowdrift disaster of the highway is studied,and the distribution law of wind field and snow field on the embankment surface with w-beam barrier and cable barrier is obtained. The results show that the snowdrift velocity increases from the foot of the embankment on the upwind side till to the w-beam barrier installed at the shoulder of or the central divider of the road. Then it moves to the road surface through the gap in the lower part of the w-beam barrier. At this time the w-beam barrier disturbs the wind field near the ground,causing a weak wind area to appear behind the beam,resulting in a large number of snow particles deposited. Especially when the lower gap of the w-beam barrier is filled with snow,the road area behind the w-beam barrier covers the driving lane with snow,which seriously affects the road capacity. While the section without setting up a barrier or setting a cable barrier is conducive to the passage of snowdrift flow. Considering the uncertainty of future climate change,in order to better prevent the impact of snowdrift on traffic operation safety,it is proposed to replace the w-beam barrier in some areas with serious wind and snow disasters with cable barrier that meet the safety requirements of expressways. Moreover,other snowdrift protection measures such as snow fences,snow barriers and snow walls can also be adopted. The research results can provide useful reference for snow removal of the expressway and new expressway construction in the windy and snow areas of Xinjiang. © 2022 Science Press (China).  相似文献   

20.
Summer monsoon rainfall was simulated by a global 20 km-mesh atmospheric general circulation model (AGCM), focusing on the changes in the summer monsoon rainfall of Bangladesh. Calibration and validation of AGCM were performed over Bangladesh for generating summer monsoon rainfall scenarios. The model-produced summer monsoon rainfall was calibrated with a ground-based observational data in Bangladesh during the period 1979–2003. The TRMM 3B43 V6 data are also used for understanding the model performance. The AGCM output obtained through validation process made it confident to be used for near future and future summer monsoon rainfall projection in Bangladesh. In the present-day (1979–2003) climate simulations, the high-resolution AGCM produces the summer monsoon rainfall better as a spatial distribution over SAARC region in comparison with TRMM but magnitude may be different. Summer monsoon rainfall projection for Bangladesh was experimentally obtained for near future and future during the period 2015–2034 and 2075–2099, respectively. This work reveals that summer monsoon rainfall simulated by a high-resolution AGCM is not directly applicable to application purpose. However, acceptable performance was obtained in estimating summer monsoon rainfall over Bangladesh after calibration and validation. This study predicts that in near future, summer monsoon rainfall on an average may decrease about ?0.5 % during the period 2015–2034 and future summer monsoon rainfall may increase about 0.4 % during the period 2075–2099.  相似文献   

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