The aperture of natural rock fractures significantly affects the deformation and strength properties of rock masses,as well as the hydrodynamic properties of fractured rock masses.The conventional measurement methods ...The aperture of natural rock fractures significantly affects the deformation and strength properties of rock masses,as well as the hydrodynamic properties of fractured rock masses.The conventional measurement methods are inadequate for collecting data on high-steep rock slopes in complex mountainous regions.This study establishes a high-resolution three-dimensional model of a rock slope using unmanned aerial vehicle(UAV)multi-angle nap-of-the-object photogrammetry to obtain edge feature points of fractures.Fracture opening morphology is characterized using coordinate projection and transformation.Fracture central axis is determined using vertical measuring lines,allowing for the interpretation of aperture of adaptive fracture shape.The feasibility and reliability of the new method are verified at a construction site of a railway in southeast Tibet,China.The study shows that the fracture aperture has a significant interval effect and size effect.The optimal sampling length for fractures is approximately 0.5e1 m,and the optimal aperture interpretation results can be achieved when the measuring line spacing is 1%of the sampling length.Tensile fractures in the study area generally have larger apertures than shear fractures,and their tendency to increase with slope height is also greater than that of shear fractures.The aperture of tensile fractures is generally positively correlated with their trace length,while the correlation between the aperture of shear fractures and their trace length appears to be weak.Fractures of different orientations exhibit certain differences in their distribution of aperture,but generally follow the forms of normal,log-normal,and gamma distributions.This study provides essential data support for rock and slope stability evaluation,which is of significant practical importance.展开更多
Remote sensing has played a pivotal role in our understanding of the geometry of dykes and dyke swarms on Earth,Venus and Mars(West and Ernst,1991;Mege and Masson,1995;Ernst et al.,2005).Since the 1970’s
Unmanned Aerial Vehicles(UAV)tilt photogrammetry technology can quickly acquire image data in a short time.This technology has been widely used in all walks of life with the rapid development in recent years especiall...Unmanned Aerial Vehicles(UAV)tilt photogrammetry technology can quickly acquire image data in a short time.This technology has been widely used in all walks of life with the rapid development in recent years especially in the rapid acquisition of high-resolution remote sensing images,because of its advantages of high efficiency,reliability,low cost and high precision.Fully using the UAV tilt photogrammetry technology,the construction image progress can be observed by stages,and the construction site can be reasonably and optimally arranged through three-dimensional modeling to create a civilized,safe and tidy construction environment.展开更多
基于无人机未来融入国家空域系统的发展趋势,针对无人机数量增多导致与有人机之间碰撞风险增大的问题,根据ADS-B IN的优势和特点,提出了一种融合空域下,无人机利用ADS B IN进行冲突探测和解脱的模型。模型中依据飞行器的具体参数划设了...基于无人机未来融入国家空域系统的发展趋势,针对无人机数量增多导致与有人机之间碰撞风险增大的问题,根据ADS-B IN的优势和特点,提出了一种融合空域下,无人机利用ADS B IN进行冲突探测和解脱的模型。模型中依据飞行器的具体参数划设了有人机的安全区和保护区,并利用几何法设置潜在碰撞风险判定标准和解脱完成标准,根据最小机动和最快解脱原则,无人机在空域内进行实时探测并对可能产生冲突的有人机主动避让,在避让过程中分别考虑了速度解脱、航向解脱、速度和航向混合解脱三种解脱策略。在实际运行场景中,同时考虑了风对航空器速度和航向的影响,进行了风速修正。设置三种运行场景进行了仿真试验,仿真结果满足最低安全间隔的要求。为进一步验证模型的优势,另与传统的人工势场方法进行了仿真对比。以上两种结果均证实了模型的可靠性和优越性,未来可用于降低管制员工作负荷,提高空域整体安全性。展开更多
基金This work was supported by the National Nature Science Foundation of China(Grant Nos.42177139 and 41941017)the Natural Science Foundation Project of Jilin Province,China(Grant No.20230101088JC).The authors would like to thank the anonymous reviewers for their comments and suggestions.
文摘The aperture of natural rock fractures significantly affects the deformation and strength properties of rock masses,as well as the hydrodynamic properties of fractured rock masses.The conventional measurement methods are inadequate for collecting data on high-steep rock slopes in complex mountainous regions.This study establishes a high-resolution three-dimensional model of a rock slope using unmanned aerial vehicle(UAV)multi-angle nap-of-the-object photogrammetry to obtain edge feature points of fractures.Fracture opening morphology is characterized using coordinate projection and transformation.Fracture central axis is determined using vertical measuring lines,allowing for the interpretation of aperture of adaptive fracture shape.The feasibility and reliability of the new method are verified at a construction site of a railway in southeast Tibet,China.The study shows that the fracture aperture has a significant interval effect and size effect.The optimal sampling length for fractures is approximately 0.5e1 m,and the optimal aperture interpretation results can be achieved when the measuring line spacing is 1%of the sampling length.Tensile fractures in the study area generally have larger apertures than shear fractures,and their tendency to increase with slope height is also greater than that of shear fractures.The aperture of tensile fractures is generally positively correlated with their trace length,while the correlation between the aperture of shear fractures and their trace length appears to be weak.Fractures of different orientations exhibit certain differences in their distribution of aperture,but generally follow the forms of normal,log-normal,and gamma distributions.This study provides essential data support for rock and slope stability evaluation,which is of significant practical importance.
文摘Remote sensing has played a pivotal role in our understanding of the geometry of dykes and dyke swarms on Earth,Venus and Mars(West and Ernst,1991;Mege and Masson,1995;Ernst et al.,2005).Since the 1970’s
文摘Unmanned Aerial Vehicles(UAV)tilt photogrammetry technology can quickly acquire image data in a short time.This technology has been widely used in all walks of life with the rapid development in recent years especially in the rapid acquisition of high-resolution remote sensing images,because of its advantages of high efficiency,reliability,low cost and high precision.Fully using the UAV tilt photogrammetry technology,the construction image progress can be observed by stages,and the construction site can be reasonably and optimally arranged through three-dimensional modeling to create a civilized,safe and tidy construction environment.
文摘基于无人机未来融入国家空域系统的发展趋势,针对无人机数量增多导致与有人机之间碰撞风险增大的问题,根据ADS-B IN的优势和特点,提出了一种融合空域下,无人机利用ADS B IN进行冲突探测和解脱的模型。模型中依据飞行器的具体参数划设了有人机的安全区和保护区,并利用几何法设置潜在碰撞风险判定标准和解脱完成标准,根据最小机动和最快解脱原则,无人机在空域内进行实时探测并对可能产生冲突的有人机主动避让,在避让过程中分别考虑了速度解脱、航向解脱、速度和航向混合解脱三种解脱策略。在实际运行场景中,同时考虑了风对航空器速度和航向的影响,进行了风速修正。设置三种运行场景进行了仿真试验,仿真结果满足最低安全间隔的要求。为进一步验证模型的优势,另与传统的人工势场方法进行了仿真对比。以上两种结果均证实了模型的可靠性和优越性,未来可用于降低管制员工作负荷,提高空域整体安全性。
