The Qinghai-Tibet Railway(QTR) passes through 281 km of sandy land, 11.07 km of which causes serious sand damage to the railway and thus, the control of blown sand is important for the safe operation of the railway. C...The Qinghai-Tibet Railway(QTR) passes through 281 km of sandy land, 11.07 km of which causes serious sand damage to the railway and thus, the control of blown sand is important for the safe operation of the railway. Construction of the railway and sand prevention system greatly changed the blown sand transport of the primary surface. Effective and feasible sand-control measures include stone checkerboard barriers(SCBs), sand fences(SFs), and gravel coverings. This study simulated the embankments, SCBs and SFs of the QTR in a wind tunnel, and analyzed their respective wind profile, sand deposition, and sand-blocking rate(SBR) in conjunction with field data, aiming at studying the influence of Golmud-Lhasa section of the QTR and sand prevention system on blown sand transport. The results of wind tunnel experiments showed that wind speed increased by 67.7%–77.3% at the upwind shoulder of the embankment and decreased by 50.0%–83.3% at upwind foot of embankment. Wind speed decreased by 50.0%–100.0% after passing through the first SF, and 72.2%–100.0% after the first row of stones within the first SCB grid. In the experiment of sand deposition, the higher the wind speed, the lower the SBR of SCB and SF. From field investigation, the amount of sand blocked by the four SFs decreased exponentially and its SBR was about 50.0%. By contrast, SCB could only block lower amounts of sand, but had a higher SBR(96.7%) than SF. Although, results show that SFs and SCBs along the Golmud-Lhasa section of the QTR provide an obvious sand blocking effect, they lead to the deposition of a large amount of sand, which forms artificial dunes and becomes a new source of sand damage.展开更多
This paper examines the mutual displacement of functional elements （FE） of risky technical systems （RTS）. To this group of systems belong transport systems, technical systems operating in heavy regimes, energy and...This paper examines the mutual displacement of functional elements （FE） of risky technical systems （RTS）. To this group of systems belong transport systems, technical systems operating in heavy regimes, energy and power systems, building structures. etc. A unit of mutual displacement of the functional elements of RTS is introduced, as well as a definition of the deformator of the system. The value of the deformator of a sample system is determined.展开更多
Transport risk assessment for the environment has two important aspects--problem solving model and solution veracity. Problem solving model is larger understanding of tasks interconnection, which represents in itself ...Transport risk assessment for the environment has two important aspects--problem solving model and solution veracity. Problem solving model is larger understanding of tasks interconnection, which represents in itself partial solution of general risk assessment. Veracity of solution means how the results are consistent with the reality. By researching of both aspects, it rises many unanswered questions. It is concerned about verification and validation of risk assessment results. By risk assessment for the environment it is possible to meet wide variety of more or less good soluble problems. It exists simple problems based on risk assessment of common traffic accidents connected with service charge outflow. On the other site, it exists complex problems of risk assessment connected with dangerous goods transport by traffic or pipelines. By simple problems solving there are not many questions about risk assessment veracity. It is possible to determine traffic accidents frequencies and service charge outflows consequences on the basis of examined events in transportation with great veracity. By complex problems the situation is quite different. The frequencies of large accidents are very low but the consequences for the environment may be large. Both are encumbered by large level of uncertainty. That is why the question is rising. To what degree, it is in these cases correct to make decision based on risk assessment.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.40930741)National Basic Research Program of China(No.2012CB026105)
文摘The Qinghai-Tibet Railway(QTR) passes through 281 km of sandy land, 11.07 km of which causes serious sand damage to the railway and thus, the control of blown sand is important for the safe operation of the railway. Construction of the railway and sand prevention system greatly changed the blown sand transport of the primary surface. Effective and feasible sand-control measures include stone checkerboard barriers(SCBs), sand fences(SFs), and gravel coverings. This study simulated the embankments, SCBs and SFs of the QTR in a wind tunnel, and analyzed their respective wind profile, sand deposition, and sand-blocking rate(SBR) in conjunction with field data, aiming at studying the influence of Golmud-Lhasa section of the QTR and sand prevention system on blown sand transport. The results of wind tunnel experiments showed that wind speed increased by 67.7%–77.3% at the upwind shoulder of the embankment and decreased by 50.0%–83.3% at upwind foot of embankment. Wind speed decreased by 50.0%–100.0% after passing through the first SF, and 72.2%–100.0% after the first row of stones within the first SCB grid. In the experiment of sand deposition, the higher the wind speed, the lower the SBR of SCB and SF. From field investigation, the amount of sand blocked by the four SFs decreased exponentially and its SBR was about 50.0%. By contrast, SCB could only block lower amounts of sand, but had a higher SBR(96.7%) than SF. Although, results show that SFs and SCBs along the Golmud-Lhasa section of the QTR provide an obvious sand blocking effect, they lead to the deposition of a large amount of sand, which forms artificial dunes and becomes a new source of sand damage.
文摘This paper examines the mutual displacement of functional elements （FE） of risky technical systems （RTS）. To this group of systems belong transport systems, technical systems operating in heavy regimes, energy and power systems, building structures. etc. A unit of mutual displacement of the functional elements of RTS is introduced, as well as a definition of the deformator of the system. The value of the deformator of a sample system is determined.
文摘Transport risk assessment for the environment has two important aspects--problem solving model and solution veracity. Problem solving model is larger understanding of tasks interconnection, which represents in itself partial solution of general risk assessment. Veracity of solution means how the results are consistent with the reality. By researching of both aspects, it rises many unanswered questions. It is concerned about verification and validation of risk assessment results. By risk assessment for the environment it is possible to meet wide variety of more or less good soluble problems. It exists simple problems based on risk assessment of common traffic accidents connected with service charge outflow. On the other site, it exists complex problems of risk assessment connected with dangerous goods transport by traffic or pipelines. By simple problems solving there are not many questions about risk assessment veracity. It is possible to determine traffic accidents frequencies and service charge outflows consequences on the basis of examined events in transportation with great veracity. By complex problems the situation is quite different. The frequencies of large accidents are very low but the consequences for the environment may be large. Both are encumbered by large level of uncertainty. That is why the question is rising. To what degree, it is in these cases correct to make decision based on risk assessment.
