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Influence of wind-blown sand content on the mechanical quality state of ballast bed in sandy railways
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作者 Yihao Chi Hong Xiao +3 位作者 Zhihai Zhang Yang Wang Zhongxia Qian Weize Zhao 《Railway Engineering Science》 EI 2024年第4期533-550,共18页
During the operation of sandy railways, the challenge posed by wind-blown sand is a persistent issue. An in-depth study on the influence of wind-blown sand content on the macroscopic and microscopic mechanical propert... During the operation of sandy railways, the challenge posed by wind-blown sand is a persistent issue. An in-depth study on the influence of wind-blown sand content on the macroscopic and microscopic mechanical properties of the ballast bed is of great significance for understanding the potential problems of sandy railways and proposing reasonable and adequate maintenance and repair strategies. Building upon existing research, this study proposes a new assessment indicator for sand content. Utilizing the discrete element method(DEM) and fully considering the complex interactions between ballast and sand particles, three-dimensional(3D) multi-scale analysis models of sandy ballast beds with different wind-blown sand contents are established and validated through field experiments. The effects of varying wind-blown sand content on the microscopic contact distribution and macroscopic mechanical behavior(such as resistance and support stiffness) of ballast beds are carefully analyzed. The results show that with the increase in sand content, the average contact force and coordination number between ballast particles gradually decrease, and the disparity in contact forces between different layers of the ballast bed diminishes. The longitudinal and lateral resistance of the ballast bed initially decreases and then increases, with a critical point at 10% sand content. At 15% sand content, the lateral resistance is mainly shared by the ballast shoulder. The longitudinal resistance sharing ratio is always the largest on the sleeper side, followed by that at the sleeper bottom, and the smallest on the ballast shoulder. When the sand content exceeds 10%, the contribution of sand particles to stiffness significantly increases, leading to an accelerated growth rate of the overall support stiffness of the ballast bed, which is highly detrimental to the long-term service performance of the ballast bed. In conclusion, it is recommended that maintenance and repair operations should be promptly conducted when the sand content of the ballast bed reaches or exceeds 10%. 展开更多
关键词 sandy railway wind-blown sand content Discrete element method(DEM) Macroscopic and microscopic mechanical properties Maintenance and repair strategies
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Progress on research and mitigation of wind-blown sand risk in Dunhuang Singing Sand Mountain and Crescent Spring Scenic area,China 被引量:1
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作者 BenLi Liu KeCun Zhang +6 位作者 JianJun Qu HaiJiang Li QingHe Niu ZhiShan An YingJun Pang LiHai Tan GenSheng Yang 《Research in Cold and Arid Regions》 CSCD 2023年第3期113-121,共9页
The Singing Sand Mountain and Crescent Spring Scenic Spot in Dunhuang,Northwest China is a world-renowned desert attraction that is also an integral component of the Dunhuang UNESCO Global Geopark.This scenic area und... The Singing Sand Mountain and Crescent Spring Scenic Spot in Dunhuang,Northwest China is a world-renowned desert attraction that is also an integral component of the Dunhuang UNESCO Global Geopark.This scenic area underwent a 30-year transformation,i.e.,from a severe sand risk with spring water threatened by sand burial due to dune deformation,to restoration of the original sand flow field and mitigation of the sand burial problem.The current paper summarizes the research on the intensive monitoring of the dynamic change of star dunes near the spring,observation of wind and sand flow movement,and then restoring the harmonic vibration of the sand particles(singing sand)that were previously silenced.The existing and prospective impacts of anthropogenic and natural forces on the deformation of the sand dunes are investigated by integrated methods,guiding the implementation of mitigating measures with significant ameliorative effects.Contrast to common sand control practices that aim to reduce wind speed and stop blown sands,our research highlights the importance of maintaining the natural wind flow field in stabilizing surrounding dunes.These mitigation measures consist of removing excessive vegetation and newly constructed buildings to recover the original wind flow field and sand transport activity.Such research and mitigation efforts ensure the scientific protection and restoration of the special desert landform,and contribute to the mutual enhancement of the conservation and exploitation of this desert scenic spot and similar sites. 展开更多
关键词 Singing sand Mountain Crescent Spring wind-blown sand problem Wind flow field Star dune
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Damage by wind-blown sand and its control measures along the Taklimakan Desert Highway in China 被引量:15
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作者 LI Congjuan WANG Yongdong +4 位作者 LEI Jiaqiang XU Xinwen WANG Shijie FAN Jinglong LI Shengyu 《Journal of Arid Land》 SCIE CSCD 2021年第1期98-106,共9页
Desertification is one of the most serious environmental problems in the world,especially in the arid desert regions.Combating desertification,therefore,is an urgent task on a regional or even global scale.The Taklima... Desertification is one of the most serious environmental problems in the world,especially in the arid desert regions.Combating desertification,therefore,is an urgent task on a regional or even global scale.The Taklimakan Desert in China is the second largest mobile desert in the world and has been called the''Dead Sea''due to few organisms can exist in such a harsh environment.The Taklimakan Desert Highway,the longest desert highway(a total length of 446 km)across the mobile desert in the world,was built in the 1990s within the Taklimakan Desert.It has an important strategic significance regarding oil and gas resources exploration and plays a vital role in the socio-economic development of southern Xinjiang,China.However,wind-blow sand seriously damages the smoothness of the desert highway and,in this case,mechanical sand control system(including sand barrier fences and straw checkerboards)was used early in the life of the desert highway to protect the road.Unfortunately,more than 70%of the sand barrier fences and straw checkerboards have lost their functions,and the desert highway has often been buried and frequently blocked since 1999.To solve this problem,a long artificial shelterbelt with the length of 437 km was built along the desert highway since 2000.However,some potential problems still exist for the sustainable development of the desert highway,such as water shortage,strong sandstorms,extreme environmental characteristics and large maintenance costs.The study aims to provide an overview of the damages caused by wind-blown sand and the effects of sand control measures along the Taklimakan Desert Highway.Ultimately,we provide some suggestions for the biological sand control system to ensure the sustainable development of the Taklimakan Desert Highway,such as screening drought-resistant species to reduce the irrigation requirement and ensure the sound development of groundwater,screening halophytes to restore vegetation in the case of soil salinization,and planting cash crops,such as Cistanche,Wolfberry,Apocynum and other cash crops to decrease the high cost of maintenance on highways and shelterbelts. 展开更多
关键词 wind-blown sand sand barrier fences artificial shelterbelt mechanical sand control measure biological sand control measure sustainable development Taklimakan Desert Highway
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Effect of the W-beam central guardrails on wind-blown sand deposition on desert expressways in sandy regions 被引量:5
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作者 WANG Cui LI Shengyu +2 位作者 LEI Jiaqiang LI Zhinong CHEN Jie 《Journal of Arid Land》 SCIE CSCD 2020年第1期154-165,共12页
Many desert expressways are affected by the deposition of the wind-blown sand,which might block the movement of vehicles or cause accidents.W-beam central guardrails,which are used to improve the safety of desert expr... Many desert expressways are affected by the deposition of the wind-blown sand,which might block the movement of vehicles or cause accidents.W-beam central guardrails,which are used to improve the safety of desert expressways,are thought to influence the deposition of the wind-blown sand,but this has yet not to be studied adequately.To address this issue,we conducted a wind tunnel test to simulate and explore how the W-beam central guardrails affect the airflow,the wind-blown sand flux and the deposition of the wind-blown sand on desert expressways in sandy regions.The subgrade model is 3.5 cm high and 80.0 cm wide,with a bank slope ratio of 1:3.The W-beam central guardrails model is 3.7 cm high,which included a 1.4-cm-high W-beam and a 2.3-cm-high stand column.The wind velocity was measured by using pitot-static tubes placed at nine different heights(1,2,3,5,7,10,15,30 and 50 cm)above the floor of the chamber.The vertical distribution of the wind-blown sand flux in the wind tunnel was measured by using the sand sampler,which was sectioned into 20 intervals.In addition,we measured the wind-blown sand flux in the field at K50 of the Bachu-Shache desert expressway in the Taklimakan Desert on 11 May 2016,by using a customized 78-cm-high gradient sand sampler for the sand flux structure test.Obstruction by the subgrade leads to the formation of two weak wind zones located at the foot of the windward slope and at the leeward slope of the subgrade,and the wind velocity on the leeward side weakens significantly.The W-beam central guardrails decrease the leeward wind velocity,whereas the velocity increases through the bottom gaps and over the top of the W-beam central guardrails.The vertical distribution of the wind-blown sand flux measured by wind tunnel follows neither a power-law nor an exponential function when affected by either the subgrade or the W-beam central guardrails.At 0.0H and 0.5H(where H=3.5 cm,which is the height of the subgrade),the sand transport is less at the 3 cm height from the subgrade surface than at the 1 and 5 cm heights as a result of obstruction by the W-beam central guardrails,and the maximum sand transportation occurs at the 5 cm height affected by the subgrade surface.The average saltation height in the presence of the W-beam central guardrails is greater than the subgrade height.The field test shows that the sand deposits on the overtaking lane leeward of the W-beam central guardrails and that the thickness of the deposited sand is determined by the difference in the sand mass transported between the inlet and outlet points,which is consistent with the position of the minimum wind velocity in the wind tunnel test.The results of this study could help us to understand the hazards of the wind-blown sand onto subgrade with the W-beam central guardrails. 展开更多
关键词 wind velocity field wind-blown sand flux W-beam central guardrails sand deposition desert expressway wind tunnel test Taklimakan Desert
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Experimental analysis of sand particles' lift-off and incident velocities in wind-blown sand flux 被引量:9
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作者 Li Xie Zhibao Dong Xiaojing Zheng 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2005年第6期564-573,共10页
The probability distributions of sand particles' lift-off and incident velocities in a wind-blown sand flux play very important roles in the simulation of the wind-blown sand movement. In this paper, the vertical and... The probability distributions of sand particles' lift-off and incident velocities in a wind-blown sand flux play very important roles in the simulation of the wind-blown sand movement. In this paper, the vertical and the horizontal speeds of sand particles located at 1.0 mm above a sand-bed in a wind-blown sand flux are observed with the aid of Phase Doppler Anemometry (PDA) in a wind tunnel. Based on the experimental data, the probability distributions of not only the vertical lift-off speed but also the lift-off velocity as well as its horizontal component and the incident velocity as well as its vertical and horizontal components can be obtained by the equal distance histogram method. It is found, according to the results of the X^2-test for these probability distributions, that the probability density functions (pdf's) of the sand particles' lift-off and incident velocities as well as their vertical com- ponents are described by the Gamma density function with different peak values and shapes and the downwind incident and lift-off horizontal speeds, respectively, can be described by the lognormal and the Gamma density functions, These pdf's depend on not only the sand particle diameter but also the wind speed. 展开更多
关键词 wind-blown sand movement - Tunnel experiment- Incident velocity. Lift-off velocity Probability density
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Dynamic Characteristics Analysis on Wind-Blown Sand Ground under Dynamic Compaction Vibration 被引量:5
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作者 Jihui Ding Jinguo Liang Wei Wang 《World Journal of Engineering and Technology》 2014年第3期171-178,共8页
In the 6000 kN·m energy level dynamic compaction on Inner Mongolia wind-blown sand foundation treatment process, the dynamic characteristics and dynamic response are measured. Vibration action time, vibration mai... In the 6000 kN·m energy level dynamic compaction on Inner Mongolia wind-blown sand foundation treatment process, the dynamic characteristics and dynamic response are measured. Vibration action time, vibration main frequency, peak acceleration and peak velocity are analyzed. The vibration acting time is very short, the vertical average vibration acting time increases obviously with distance increasing, and the horizontal average vibration time does hardly change. The main frequency of vibration is at 4.60 - 24.90 Hz, which depends on the soil properties and soil layer distribution. The peak acceleration and peak velocity space distribution are similar. The maximum of horizontal acceleration peak is close to vertical velocity peak, and is near to 51 g under rammer. The maximum of horizontal velocity peak is close to vertical velocity peak, and is near to 54 m/s under rammer. The peak acceleration and velocity are rapidly attenuated, but the vertical peak acceleration and peak velocity are slowly attenuated than horizontal direction. The effective treating depth arrives 13 m for wind-blown wind, peak acceleration is 1.8 g or so, and peak velocity is 2.1 m/s or so. Horizontal treating range is 2.6 times of rammer diameter, and vertical treating range is 5.65 times of rammer diameter. 展开更多
关键词 wind-blown sand GROUND DYNAMIC COMPACTION VIBRATION Effects DYNAMIC Characteristics Field EXPERIMENT
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Electromagnetic scattering of charged particles in a strong wind-blown sand electric field
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作者 Xingcai Li Xuan Gao Juan Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第3期218-222,共5页
Some field experimental results have shown that the moving sands or dust aerosols in nature are usually electrified,and those charged particles also produce a strong electric field in air, which is named as wind-blown... Some field experimental results have shown that the moving sands or dust aerosols in nature are usually electrified,and those charged particles also produce a strong electric field in air, which is named as wind-blown sand electric field.Some scholars have pointed out that the net charge on the particle significantly enhances its electromagnetic(EM) extinction properties, but up to now, there is no conclusive research on the effect of the environmental electric field. Based on the extended Mie theory, the effect of the electric field in a sandstorm on the EM attenuation properties of the charged larger dust particle is studied. The numerical results indicate that the environmental electric field also has a great influence on the particle's optical properties, and the stronger the electric field, the bigger the effect. In addition, the charged angle, the charge density, and the particle radius all have a specific impact on the charged particle's optical properties. 展开更多
关键词 wind-blown sand electric field extended MIE theory CHARGED particle scattering
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Energy Consumption and Erosion Mechanism of Polyester Fiber Reinforced Cement Composite in Wind-blown Sand Environments
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作者 HAO Yunhong LIU Yanchen +1 位作者 LI Yonggui GAO Feng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2022年第4期666-676,共11页
Considering the economic and environmental benefits associated with the recycling of polyester(PET)fibres,it is vital to study the application of fibre-reinforced cement composites.According to the characteristics of ... Considering the economic and environmental benefits associated with the recycling of polyester(PET)fibres,it is vital to study the application of fibre-reinforced cement composites.According to the characteristics of the wind-blown sand environment in Inner Mongolia,the erosion resistance of the polyester fibre-reinforced cement composites(PETFRCC)with different PET fibre contents to various erosion angles,velocities and sand particle flows was investigated by the gas-blast method.Based on the actual conditions of sandstorms in Inner Mongolia,the sand erosion parameters required for testing were calculated by the similarity theory.The elastic-plastic model and rigid plastic model of PETFRCC and cement mortar were established,and the energy consumption mechanism of the model under particle impact was analyzed.The experimental results indicate that the microstructure of PETFRCC rafter hydration causes a spring-like buffering effect,and the deformation of PETFRCC under the same impact load is slightly smaller than that of cement mortar,and the damage mechanism of PETFRCC is mainly characterized by fiber deformation and slight brittle spalling of matrix.And under the most unfavorable conditions of the erosion,the erosion rate of 0.5PETFRCC is about 57.69%lower than that of cement mortar,showing better erosion resistance. 展开更多
关键词 wind-blown sand environment erosion resistance polyester fibre-reinforced cement composite energy consumption mechanism erosion mechanism
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Probability of rebound and eject of sand particles in wind-blown sand movement
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作者 Li Xie Xiaojing Zheng 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第5期471-475,共5页
When incident particles impact into a sand bed in wind-blown sand movement, rebound of the incident particles and eject of the sand particles by the incident particles affect directly the development of wind sand flux... When incident particles impact into a sand bed in wind-blown sand movement, rebound of the incident particles and eject of the sand particles by the incident particles affect directly the development of wind sand flux. In order to obtain rebound and eject lift-off probability of the sand particles, we apply the particle-bed stochastic collision model presented in our pervious works to derive analytic solutions of velocities of the incident and impacted particles in the postcollision bed. In order to describe randomness inherent in the real particle-bed collision, we take the incident angle, the impact position and the direction of resultant action of sand particles in sand bed on the impacted sand particle as ran- dom variables, and calculate the rebound and eject velocities, angles and coefficients (ratio of rebound and eject velocity to incident velocity). Numerical results are found in accordance with current experimental results. The rebound and eject liftoff probabilities versus the incident and creeping velocities are predicted. 展开更多
关键词 wind-blown sand movement Rebound andeject coefficient Rebound and eject lift-off probability
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珠三角地区富水砂层深基坑施工涌水涌砂安全风险控制 被引量:1
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作者 王芳泓 《路基工程》 2024年第1期198-205,共8页
针对珠三角地区水文地质条件复杂且有富水砂层的各类深基坑施工易发涌水涌砂现象,结合现场处置过程中遇到的实际问题,进行风险分析,总结提出涌水涌砂预防管理要点和处置措施。应加强全过程施工质量管控,防止突涌水发生;另一方面应做好... 针对珠三角地区水文地质条件复杂且有富水砂层的各类深基坑施工易发涌水涌砂现象,结合现场处置过程中遇到的实际问题,进行风险分析,总结提出涌水涌砂预防管理要点和处置措施。应加强全过程施工质量管控,防止突涌水发生;另一方面应做好充足的预防、准备、响应等应急管理工作,确保突涌发生后可成功地进行现场处置。 展开更多
关键词 珠三角地区 富水砂层 深基坑 围护结构 涌水涌砂 险情处置
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河西走廊绿洲外缘典型风沙防护体系的功能稳定性评估
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作者 何晨晨 王振亭 张春来 《福建农林大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第4期549-555,共7页
【目的】评估中国北方防沙带核心区域——河西走廊各绿洲外缘风沙防护体系的功能稳定性,为优化防护林体系提供参考。【方法】基于风沙综合防护体系功能稳定性的定义和判据,建立河西走廊绿洲外缘风沙防护体系功能稳定性的定性评估与检验... 【目的】评估中国北方防沙带核心区域——河西走廊各绿洲外缘风沙防护体系的功能稳定性,为优化防护林体系提供参考。【方法】基于风沙综合防护体系功能稳定性的定义和判据,建立河西走廊绿洲外缘风沙防护体系功能稳定性的定性评估与检验方法。【结果】河西走廊东部石羊河流域和中部黑河流域存在一些稳态和非稳态的风沙综合防护体系,西部疏勒河流域风沙综合防护体系则以亚稳态为主。【结论】河西走廊绿洲外缘东部和中部各风沙防护体系的功能稳定性差异较大,而西部地区风沙防护体系的功能稳定性差异较小。在风季前、后,稳态防护体系基本保持稳定,而亚稳态和非稳态体系不稳定。 展开更多
关键词 河西走廊 绿洲 风沙防护体系 功能稳定性 地表积蚀状况
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天津院砂石骨料领域破碎装备研发成果及发展
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作者 王平 《中国水泥》 CAS 2024年第4期53-59,共7页
水泥工业经过高速发展后产能饱和,行情不佳,相反,机制砂石骨料行业近十几年发展迅猛。由于两者矿山及破碎系统技术相似,近几年,水泥行业全产业链进入机制砂石骨料行业进行拓展,带动水泥破碎装备进入骨料市场。天津院破碎板块深耕骨料市... 水泥工业经过高速发展后产能饱和,行情不佳,相反,机制砂石骨料行业近十几年发展迅猛。由于两者矿山及破碎系统技术相似,近几年,水泥行业全产业链进入机制砂石骨料行业进行拓展,带动水泥破碎装备进入骨料市场。天津院破碎板块深耕骨料市场,开发出多款适应新行业的破碎机、喂料设备、预筛分设备、制砂机等,并且有了较多成功的应用;同时,天津院破碎板块对系统工艺和物料试验也进行了研究,进一步掌握其设计及试验方法。面对新的市场形势,天津院对破碎装备未来的研发、制造、智能化等制定了发展规划,提出了较高的要求。 展开更多
关键词 水泥 机制砂石骨料 破碎装备 研发
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我国高速动车组撒砂装置现状及发展趋势
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作者 胡淼 王善方 +3 位作者 董光进 马永靖 张方亮 李新康 《铁道车辆》 2024年第1期157-160,共4页
文章介绍了我国和谐号、复兴号高速动车组撒砂装置的现状以及近几年国外撒砂装置最新研制情况,并在此基础上预测了我国高速动车组撒砂装置未来技术发展趋势。
关键词 动车组 撒砂装置 现状 发展趋势
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Wind tunnel test on the effect of metal net fences on sand flux in a Gobi Desert, China 被引量:20
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作者 WANG Tao QU Jianjun +2 位作者 LING Yuquan XIE Shengbo XIAO Jianhua 《Journal of Arid Land》 SCIE CSCD 2017年第6期888-899,共12页
The Lanzhou-Xinjiang High-speed Railway runs through an expansive windy area in a Gobi Desert, and sand-blocking fences were built to protect the railway from destruction by wind-blown sand. However, the shielding eff... The Lanzhou-Xinjiang High-speed Railway runs through an expansive windy area in a Gobi Desert, and sand-blocking fences were built to protect the railway from destruction by wind-blown sand. However, the shielding effect of the sand-blocking fence is below the expectation. In this study, effects of metal net fences with porosities of 0.5 and 0.7 were tested in a wind tunnel to determine the effectiveness of the employed two kinds of fences in reducing wind velocity and restraining wind-blown sand. Specifically, the horizontal wind velocities and sediment flux densities above the gravel surface were measured under different free-stream wind velocities for the following conditions: no fence at all, single fence with a porosity of 0.5, single fence with a porosity of 0.7, double fences with a porosity of 0.5, and double fences with a porosity of 0.7. Experimental results showed that the horizontal wind velocity was more significantly decreased by the fence with a porosity of 0.5, especially for the double fences. The horizontal wind velocity decreased approximately 65% at a distance of 3.25 m(i.e., 13 H, where H denotes the fence height) downwind the double fences, and no reverse flow or vortex was observed on the leeward side. The sediment flux density decreased exponentially with height above the gravel surface downwind in all tested fences. The reduction percentage of total sediment flux density was higher for the fence with a porosity of 0.5 than for the fence with a porosity of 0.7, especially for the double fences. Furthermore, the decreasing percentage of total sediment flux density decreased with increasing free-stream wind velocity. The results suggest that compared with metal net fence with a porosity of 0.7, the metal net fence with a porosity of 0.5 is more effective for controlling wind-blown sand in the expansive windy area where the Lanzhou-Xinjiang High-speed Railway runs through. 展开更多
关键词 wind-blown sand wind tunnel experiment porous fence flow field sediment flux density Lanzhou-Xinjiang High-speed Railway Gobi Desert
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Effects of different types of guardrails on sand transportation of desert highway pavement 被引量:1
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作者 GAO Li CHENG Jianjun +1 位作者 WANG Haifeng YUAN Xinxin 《Journal of Arid Land》 SCIE CSCD 2022年第9期993-1008,共16页
Guardrail,an important highway traffic safety facility,is mainly used to prevent vehicles from accidentally driving off the road and to ensure driving safety.Desert highway guardrails hinder the movement of wind-blown... Guardrail,an important highway traffic safety facility,is mainly used to prevent vehicles from accidentally driving off the road and to ensure driving safety.Desert highway guardrails hinder the movement of wind-blown sand,resulting in the decline of sand transportation by the pavement and the deposition of sand gains on the pavement,and endangering traffic safety.To reveal the influence of guardrails on sand transportation of desert highway pavement,we tested the flow field and sand transport volume distribution around the concrete,W-beam,and cable guardrails under different wind velocities through wind tunnel simulation.Wind velocity attenuation coefficients,sand transportation quantity,and sand transportation efficiency are used to measure sand transportation of highway pavement.The results show that the sand transportation of highway pavement was closely related to the zoning characteristics of flow field and variation of wind velocity around the guardrails.The flow field of the concrete guardrail was divided into deceleration,acceleration,and vortex zones.The interaction between the W-beam guardrail and wind-blown sand was similar to that of lower wind deflector.Behind and under the plates,there were the vortex zone and acceleration zone,respectively.The acceleration zone was conducive to transporting sand on the pavement.The cable guardrail only caused wind velocity variability within the height range of guardrail,and there was no sand deposition on the highway pavement.When the cable,W-beam,and concrete guardrails were used,the total transportation quantities on the highway pavement were 423.53,415.74,and 136.53 g/min,respectively,and sand transportation efficiencies were 99.31%,91.25%,and 12.84%,respectively.From the perspective of effective sand transportation on the pavement,the cable guardrail should be preferred as a desert highway guardrail,followed by the W-beam guardrail,and the concrete guardrail is unsuitable.The study results provide theoretical basis for the optimal design of desert highway guardrails and the prevention of wind-blown sand disasters on the highway pavement. 展开更多
关键词 desert highway wind-blown sand GUARDRAIL sand transportation capacity wind tunnel test
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Current study and prospect of the Old Red Sand along the southeast coast of China
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作者 ZhiWen Li YuXiang Dong +1 位作者 BaoSheng Li FengNian Wang 《Research in Cold and Arid Regions》 2012年第6期462-471,共10页
The Old Red Sand is composed of brown-red, red, or orange-yellow semi-cemented and medium-fine sand sediment, mainly dis- tributed along the southeast coast of China. Based on previous studies, this paper summarizes t... The Old Red Sand is composed of brown-red, red, or orange-yellow semi-cemented and medium-fine sand sediment, mainly dis- tributed along the southeast coast of China. Based on previous studies, this paper summarizes the distribution and forms, sedi- mentary characteristics, formation mechanism, developing age, reddening process and the paleo-environment, suggesting that the Old Red Sand is mainly aeolian sediment of Late Pleistocene Age. The reddening process is mainly the result of decomposition and oxidation of iron-containing minerals caused by hot and humid tropical and sub-tropical climate. In this study, existing prob- lems are discussed and the prospect of further research is presented as well. 展开更多
关键词 southeast coast of China Old Red sand current study situation PROSPECTS
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Reading the Iraqi War Narrative Sand Queen from the Perspective of Ethical Literary Criticism
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作者 WANG Ting-ting LIU Xiao 《Journal of Literature and Art Studies》 2022年第2期127-131,共5页
An US woman soldier and an Iraqi medical student were given a voice to their feelings in Helen Benedict’s Iraqi war Narrative Sand Queen.It was the first time war stories had been told by two women from different nat... An US woman soldier and an Iraqi medical student were given a voice to their feelings in Helen Benedict’s Iraqi war Narrative Sand Queen.It was the first time war stories had been told by two women from different nations.Character-narrator Kate Brady,a female American soldier,tells the story about how she tried to be an independent woman respected in American society by the way of being a female soldier,but failed in the end.The thesis focuses on Kate’s narration and analyzes her ethical choices from the perspective of Ethical Literary Criticism.By probing into the ethical situation Kate faces,and exploring the ethical conflicts among rational will and natural will on Kate,this thesis attempts to reveal what led to Kate’s ethical choices and caused her ethical confusion,and more importantly,what made her dreams shatter. 展开更多
关键词 sand Queen ethical literary criticism ethical choice ethical situation
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Mechanisms of the formation of wind-blown sand hazards and the sand control measures in Gobi areas under extremely strong winds along the Lanzhou-Xinjiang high-speed railway 被引量:2
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作者 Jianjun QU Tao WANG +5 位作者 Qinghe NIU Benli LIU Lihai TAN Qingjie HAN Yang GAO Jianhua XIAO 《Science China Earth Sciences》 SCIE EI CAS CSCD 2023年第2期292-302,共11页
The Lanzhou-Xinjiang high-speed railway(HSR)traverses areas of the Gobi Desert where extremely strong winds are frequent.These strong winds cause sand/gravel hazards,an unaddressed issue that often seriously compromis... The Lanzhou-Xinjiang high-speed railway(HSR)traverses areas of the Gobi Desert where extremely strong winds are frequent.These strong winds cause sand/gravel hazards,an unaddressed issue that often seriously compromises the safe operation of the HSR.This paper studies the mechanisms leading to wind-blown sand hazards and the outcomes of sand control projects in these areas.The main findings are as follows:(1)Cold northern airflows over the Tian Shan mountain range are accelerated by the wind tunnels and downslope effect as they pass over complex terrain comprising passes,gullies,and proluvial fans.Consequently,the wind intensity often increases two-to threefold,creating frequent high-speed winds that lead to severe sand damage along the HSR.(2)In the Gobi areas with extremely strong winds,sand grains can be lifted as high as 9 m from the ground into the air,far higher than in other areas of the desert.The sand transport rate decreases exponentially with increasing height.Both wind speed and particle size determine saltation height.Coarser particles and stronger winds provide the particles with a higher kinetic energy as they collide with the ground.In the wind zones of Baili and Yandun,the analysed study areas,the saltation layer height of wind-blown sand/gravel exceeds 3 and 2 m,respectively.(3)Based on the above findings,recently emerging sand control materials,suitable for the areas of interest,were screened and developed.Furthermore,under the proposed principle of‘supplementing blocking with trapping’,a comprehensive sand control measure was established,featuring sandblocking belts comprised of multiple rows,and high,vertical sand-trapping installations with a large grids size.The installed system showed a high efficacy,reducing sand transport rate by 87.87%and significantly decreasing the deposition of sand along a trial section of the HSR. 展开更多
关键词 Gobi areas with extremely strong winds wind-blown sand hazards Complex terrain sand/gravel flow wind-blown sand control
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荆门市砂梨产业发展现状及对策 被引量:1
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作者 刘道贤 彭曼君 +3 位作者 刘丰国 潘典进 余雪梅 胡俊丽 《中国果菜》 2023年第8期76-79,共4页
荆门市是湖北省砂梨生产的重要基地,但随着我国水果市场消费档次的提高、消费观念的改变,荆门市砂梨产业优势逐渐丧失。随着湖北省农科院“双臂梨模式”的大力推广,农旅结合的新概念得以发挥,荆门市砂梨产业又迎来了新一轮的转型升级,... 荆门市是湖北省砂梨生产的重要基地,但随着我国水果市场消费档次的提高、消费观念的改变,荆门市砂梨产业优势逐渐丧失。随着湖北省农科院“双臂梨模式”的大力推广,农旅结合的新概念得以发挥,荆门市砂梨产业又迎来了新一轮的转型升级,规模逐步扩大,随之产业问题也日渐凸显。本文阐述了荆门市砂梨产业发展现状及存在问题,提出在新环境下进一步发展壮大砂梨产业的应对策略,以期为荆门市砂梨产业的可持续发展提供参考。 展开更多
关键词 砂梨 产业现状 发展对策
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油气田开发分层注水工艺技术现状与发展 被引量:3
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作者 翟光麾 《化工设计通讯》 CAS 2023年第6期41-43,58,共4页
社会经济的快速发展为油田开发企业带来了更多发展机遇,同时也因此面临着更大的开采压力。尤其是在低渗透油藏开发无法在自然环境下实现稳定产出,整个开发过程存在较大困难。这就要求相关企业必须结合油气田开发实际,合理运用增产方法... 社会经济的快速发展为油田开发企业带来了更多发展机遇,同时也因此面临着更大的开采压力。尤其是在低渗透油藏开发无法在自然环境下实现稳定产出,整个开发过程存在较大困难。这就要求相关企业必须结合油气田开发实际,合理运用增产方法与落实相关措施,实现油气田开采规模与投产的提升,更好地满足社会经济与社会民生的发展需求。分层注水工艺在油气田开发过程中有着较为重要的作用,尤其是对于解决低渗透油藏开发难度大问题方面有着至关重要的作用。基于此,主要对油气田分层注水工艺技术的应用进行了探讨,并对其发展现状与趋势进行分析、研究。 展开更多
关键词 油气田开发 分层注水工艺技术 桥式偏心 分层防砂注水 发展形势
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