Due to a series of linear projects built along National Highway 214,the second"Permafrost Engineering Corridor"on the Qinghai-Tibet Plateau has formed.In this paper,by overcoming the problems of data decentr...Due to a series of linear projects built along National Highway 214,the second"Permafrost Engineering Corridor"on the Qinghai-Tibet Plateau has formed.In this paper,by overcoming the problems of data decentralization and standard inconsistency,permafrost characteristics and changes along the engineering corridor are systematically summarized based on the survey and monitoring data.The results show that:1)Being controlled by elevation,the permafrost is distributed in flake discontinuity with mountains as the center along the line.The total length of the road section in permafrost regions is 365 km,of which the total length of the permafrost section of National Highway 214 is 216.7 km,and the total length of the permafrost section of Gong-Yu Expressway is 197.3 km.The mean annual ground temperature(MAGT)is higher than−1.5℃,and permafrost with MAGT lower than−1.5℃ is only distributed in the sections at Bayan Har Mountain and E'la Mountain.There are obvious differences in the distribution of ground ice in the different sections along the engineering corridor.The sections with high ice content are mainly located in Zuimatan,Duogerong Plain and the top of north and south slope of Bayan Har Mountain.The permafrost thickness is controlled by the ground temperature,and permafrost thickness increases with the decrease of the ground temperature,with the change rate of about 37 m/℃.2)Local factors(topography,landform,vegetation and lithology)affect the degradation process of permafrost,and then affect the distribution,ground temperature,thickness and ice content of permafrost.Asphalt pavement has greatly changed the heat exchange balance of the original ground,resulting in serious degradation of the permafrost.Due to the influence of roadbed direction trend,the phenomenon of shady-sunny slope is very significant in most sections along the line.The warming range of permafrost under the roadbed is gradually smaller with the increase of depth,so the thawing settlement of the shallow section with high ice-content permafrost is more significant.展开更多
The national highways are always considered as the economic backbone of the country and have often assisted development work all along their routes. The National Highway (NH-1D) is the most strategic and the only all ...The national highways are always considered as the economic backbone of the country and have often assisted development work all along their routes. The National Highway (NH-1D) is the most strategic and the only all weather surface link between the two districts of Ladakh region (Kargil and Leh). The area under investigation experiences high vehicular traffic, particularly between March and August, as in the remaining months the Kargil and Leh districts?remain cutoff?from each other due to bad weather. In recent years, frequent occurrences of slope failures along the highway primarily affect the smooth functioning of the traffic movement which severely affects the life of the people of the area. Strategically, this road network is very important and plays a significant role in transportation and other activities. In order to ensure the stability of road network in the area, it becomes extremely important to understand the triggering mechanism of these failures. The present study made an attempt in this direction and the Slope Mass Rating (SMR) method has been used for slope stability analysis at different locations. The stability of the slopes was also assessed using kinematic analysis conjointly with SMR to identify the types of failure and its potential failure directions associated with each slope. The result obtained after calculating RMR from the selected facets ranges from 11 to 89 with lower values indicating presence of potentially unstable areas. Results have shown that in a total of 20 facets, 65.28% belong to wedge failure, 22.26%?belong to toppling failure and 12.45% belong to plane failure.展开更多
Based on land-use database updated with the survey of 1996, 2000, 2004 and 2008, this paper analyzed the land-use changes in the typical transect area along National Highway 106 with the aid of GIS technology and quan...Based on land-use database updated with the survey of 1996, 2000, 2004 and 2008, this paper analyzed the land-use changes in the typical transect area along National Highway 106 with the aid of GIS technology and quantitative models. The results showed that arable land had been continuously decreased from 1996 to 2008, with a loss of 65.85× 10^3 hm2 and an average decrement of 5.49×10^3 hm^2 per year, and the loss in northern areas was larger; garden land and woodland were gradually centralized to the predominance area with an increment of 25.73×10^3 hm2 and 22.37×10^3 hm2, respectively; residential and industrial land increased year after year, and the transportation land showed the equalized developing spatial pattern; the increment of construction land and encroachment on arable land in the area were deeply influenced by the national macroscopic land-use policies, the rapid advance of urbanization and the development level of the regional economy. Through this case study, it is suggested that differential land- use policies should be adopted to create good environmental conditions to guarantee food security and to promote the economic development.展开更多
Road transport and safety is a thorny problem in the world today following the occurrence, recrudescence and outcomes of accidents in our society. These accidents are a public health hazard and vector of underdevelopm...Road transport and safety is a thorny problem in the world today following the occurrence, recrudescence and outcomes of accidents in our society. These accidents are a public health hazard and vector of underdevelopment in developing countries amongst which is Cameroon. According to the World Health Organisation, road accidents ranked 3<sup>rd</sup> in position among the leading causes of mortality in the world and caused approximately 1.2 million deaths with 50 million people injured worldwide. The frequency of accidents along National Road 3 linking Douala (the economic hub of the CEMAC region) and Yaounde (the political Capital of Cameroon) remains a thorny problem. This is because 50 % of accidents in the Southern part of Cameroon occur along this stretch of the triangle of death necessitating sustainable strategies to effectively curb the situation. Efforts both structural and non-structural have been put in place over decades by the Cameroon government, civil society organisations, Non-Governmental Organisations, local communities, and other actors to contain the situation without success. This is because the measures often target road users, the state of vehicles and repair of existing roads. Along National Road 3, the poor state of the road in combination with other risk factors has been identified as prime factors that sustain accidents. This paper argues that the frequency of accidents is high, impacts on man and property enormous and the solutions to solve the problem ineffective. The methodology used for data production exploits primary and secondary sources of data from works on road transport in Cameroon, Africa and the world to assess the dynamics, outcomes, challenges and options for road accidents control on the study site. These sources integrate field surveys, administration of questionnaires, literature review and grey data sources for their findings. The results show that until recent on some roads little attention has been paid on proactive solutions visible in other countries to combat road accidents. These are the creation of multi lanes to reduce contact, investment on alternative transport modes and road modernisation to decongest existing roads. How this innovation to curb road carnage redresses the problem in question is also a focus of this paper.展开更多
The unanticipated increase in vehicle population and heavy axle loads has brought the road network of Bangladesh to a crumbling stage. The network is grossly short of its structural capacity, highly distressed and has...The unanticipated increase in vehicle population and heavy axle loads has brought the road network of Bangladesh to a crumbling stage. The network is grossly short of its structural capacity, highly distressed and has started showing signs of premature failure. The RHD （Roads and Highways Department） of Bangladesh uses 8%-10% growth rate of traffic for structural design of these highways that need to be upgraded due to present high traffic volume demand. An attempt has been made through this case study, by using traffic flow data from different computerized toll plaza established in recent times, to predict traffic growth pattern of different highways of Bangladesh. The toll collectors of different computerized toll plaza have been recording and preserving round-the-year continuous flow data in a systematic manner. The study has taken this prospect of utilizing several years of flow data along Dhaka-Chittagong Highway （N-1）, Dhaka-Sylhet Highway （N-2）, Dhaka-North Bengal Highway （N-5） and found the traffic growth factor of 21.03%, 23.79% and 11.31%, respectively, which is much higher than that transport authority of Bangladesh is currently using. By the use of accurate traffic engineering parameters such as traffic growth factors, it is possible to resist frequent distress of pavement and sustainable pavement management can be implemented by RHD.展开更多
The concentrations of twenty five heavy metals adsorbed to fine fraction of particulate matter, PM2.5 (d ≤ 2.5 μm) have been experimentally analysed at a sampling site located at the kerbside along a National Highwa...The concentrations of twenty five heavy metals adsorbed to fine fraction of particulate matter, PM2.5 (d ≤ 2.5 μm) have been experimentally analysed at a sampling site located at the kerbside along a National Highway in Delhi city, India. The sampling has been carried out for 12-hour using Ecotech Intruments, APM550. The PM2.5 has been collected on PTFE filter papers for the winter season. Later, the filter papers have been analysed for various heavy metal concentrations using ED-XRF. It has been observed that the metals concentrations are in this trend: Si > K > S > Ca = Fe > Zn = Pb > Br. it is observed that Si has high co-relation with Ca, Fe and K, which may be due to crustal origin of all three elements;while S, Br and Pb may be from vehicular exhaust emissions and/or abrasions due to brake and tyre wear. The potential health risks associated with different carcinogenic heavy metals have also been calculated. One of the health risk indicators, the excess cancer risk (ECR), is found to be in the order as As > Cd > Pb > Cr > Ni.展开更多
基金This research was supported by the National Natural Science Foundation of China(Grant No.41971093).
文摘Due to a series of linear projects built along National Highway 214,the second"Permafrost Engineering Corridor"on the Qinghai-Tibet Plateau has formed.In this paper,by overcoming the problems of data decentralization and standard inconsistency,permafrost characteristics and changes along the engineering corridor are systematically summarized based on the survey and monitoring data.The results show that:1)Being controlled by elevation,the permafrost is distributed in flake discontinuity with mountains as the center along the line.The total length of the road section in permafrost regions is 365 km,of which the total length of the permafrost section of National Highway 214 is 216.7 km,and the total length of the permafrost section of Gong-Yu Expressway is 197.3 km.The mean annual ground temperature(MAGT)is higher than−1.5℃,and permafrost with MAGT lower than−1.5℃ is only distributed in the sections at Bayan Har Mountain and E'la Mountain.There are obvious differences in the distribution of ground ice in the different sections along the engineering corridor.The sections with high ice content are mainly located in Zuimatan,Duogerong Plain and the top of north and south slope of Bayan Har Mountain.The permafrost thickness is controlled by the ground temperature,and permafrost thickness increases with the decrease of the ground temperature,with the change rate of about 37 m/℃.2)Local factors(topography,landform,vegetation and lithology)affect the degradation process of permafrost,and then affect the distribution,ground temperature,thickness and ice content of permafrost.Asphalt pavement has greatly changed the heat exchange balance of the original ground,resulting in serious degradation of the permafrost.Due to the influence of roadbed direction trend,the phenomenon of shady-sunny slope is very significant in most sections along the line.The warming range of permafrost under the roadbed is gradually smaller with the increase of depth,so the thawing settlement of the shallow section with high ice-content permafrost is more significant.
文摘The national highways are always considered as the economic backbone of the country and have often assisted development work all along their routes. The National Highway (NH-1D) is the most strategic and the only all weather surface link between the two districts of Ladakh region (Kargil and Leh). The area under investigation experiences high vehicular traffic, particularly between March and August, as in the remaining months the Kargil and Leh districts?remain cutoff?from each other due to bad weather. In recent years, frequent occurrences of slope failures along the highway primarily affect the smooth functioning of the traffic movement which severely affects the life of the people of the area. Strategically, this road network is very important and plays a significant role in transportation and other activities. In order to ensure the stability of road network in the area, it becomes extremely important to understand the triggering mechanism of these failures. The present study made an attempt in this direction and the Slope Mass Rating (SMR) method has been used for slope stability analysis at different locations. The stability of the slopes was also assessed using kinematic analysis conjointly with SMR to identify the types of failure and its potential failure directions associated with each slope. The result obtained after calculating RMR from the selected facets ranges from 11 to 89 with lower values indicating presence of potentially unstable areas. Results have shown that in a total of 20 facets, 65.28% belong to wedge failure, 22.26%?belong to toppling failure and 12.45% belong to plane failure.
基金Supported by National Natural Science Foundation of China (40635029)China Postdoctoral Science Foundation Funded Project (20090460408)
文摘Based on land-use database updated with the survey of 1996, 2000, 2004 and 2008, this paper analyzed the land-use changes in the typical transect area along National Highway 106 with the aid of GIS technology and quantitative models. The results showed that arable land had been continuously decreased from 1996 to 2008, with a loss of 65.85× 10^3 hm2 and an average decrement of 5.49×10^3 hm^2 per year, and the loss in northern areas was larger; garden land and woodland were gradually centralized to the predominance area with an increment of 25.73×10^3 hm2 and 22.37×10^3 hm2, respectively; residential and industrial land increased year after year, and the transportation land showed the equalized developing spatial pattern; the increment of construction land and encroachment on arable land in the area were deeply influenced by the national macroscopic land-use policies, the rapid advance of urbanization and the development level of the regional economy. Through this case study, it is suggested that differential land- use policies should be adopted to create good environmental conditions to guarantee food security and to promote the economic development.
文摘Road transport and safety is a thorny problem in the world today following the occurrence, recrudescence and outcomes of accidents in our society. These accidents are a public health hazard and vector of underdevelopment in developing countries amongst which is Cameroon. According to the World Health Organisation, road accidents ranked 3<sup>rd</sup> in position among the leading causes of mortality in the world and caused approximately 1.2 million deaths with 50 million people injured worldwide. The frequency of accidents along National Road 3 linking Douala (the economic hub of the CEMAC region) and Yaounde (the political Capital of Cameroon) remains a thorny problem. This is because 50 % of accidents in the Southern part of Cameroon occur along this stretch of the triangle of death necessitating sustainable strategies to effectively curb the situation. Efforts both structural and non-structural have been put in place over decades by the Cameroon government, civil society organisations, Non-Governmental Organisations, local communities, and other actors to contain the situation without success. This is because the measures often target road users, the state of vehicles and repair of existing roads. Along National Road 3, the poor state of the road in combination with other risk factors has been identified as prime factors that sustain accidents. This paper argues that the frequency of accidents is high, impacts on man and property enormous and the solutions to solve the problem ineffective. The methodology used for data production exploits primary and secondary sources of data from works on road transport in Cameroon, Africa and the world to assess the dynamics, outcomes, challenges and options for road accidents control on the study site. These sources integrate field surveys, administration of questionnaires, literature review and grey data sources for their findings. The results show that until recent on some roads little attention has been paid on proactive solutions visible in other countries to combat road accidents. These are the creation of multi lanes to reduce contact, investment on alternative transport modes and road modernisation to decongest existing roads. How this innovation to curb road carnage redresses the problem in question is also a focus of this paper.
文摘The unanticipated increase in vehicle population and heavy axle loads has brought the road network of Bangladesh to a crumbling stage. The network is grossly short of its structural capacity, highly distressed and has started showing signs of premature failure. The RHD （Roads and Highways Department） of Bangladesh uses 8%-10% growth rate of traffic for structural design of these highways that need to be upgraded due to present high traffic volume demand. An attempt has been made through this case study, by using traffic flow data from different computerized toll plaza established in recent times, to predict traffic growth pattern of different highways of Bangladesh. The toll collectors of different computerized toll plaza have been recording and preserving round-the-year continuous flow data in a systematic manner. The study has taken this prospect of utilizing several years of flow data along Dhaka-Chittagong Highway （N-1）, Dhaka-Sylhet Highway （N-2）, Dhaka-North Bengal Highway （N-5） and found the traffic growth factor of 21.03%, 23.79% and 11.31%, respectively, which is much higher than that transport authority of Bangladesh is currently using. By the use of accurate traffic engineering parameters such as traffic growth factors, it is possible to resist frequent distress of pavement and sustainable pavement management can be implemented by RHD.
文摘The concentrations of twenty five heavy metals adsorbed to fine fraction of particulate matter, PM2.5 (d ≤ 2.5 μm) have been experimentally analysed at a sampling site located at the kerbside along a National Highway in Delhi city, India. The sampling has been carried out for 12-hour using Ecotech Intruments, APM550. The PM2.5 has been collected on PTFE filter papers for the winter season. Later, the filter papers have been analysed for various heavy metal concentrations using ED-XRF. It has been observed that the metals concentrations are in this trend: Si > K > S > Ca = Fe > Zn = Pb > Br. it is observed that Si has high co-relation with Ca, Fe and K, which may be due to crustal origin of all three elements;while S, Br and Pb may be from vehicular exhaust emissions and/or abrasions due to brake and tyre wear. The potential health risks associated with different carcinogenic heavy metals have also been calculated. One of the health risk indicators, the excess cancer risk (ECR), is found to be in the order as As > Cd > Pb > Cr > Ni.
