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激光扫描仪对同一目标两次采集的点并不重合,无法通过点云的直接比较快速确定滑坡位移。考虑到单个点云位置的不确定性和区域点云密度的稳定性,将点云的密度作为滑坡表面变形的表征,提出了基于点云密度特征的滑坡位移监测方法。将离散的三维点云转化为二维的密度图像,再利用粒子图像测速技术分析位移前后两幅点云密度图像的相关性,从而计算栅格图像中各子集的相对位移值;当各子集的位移全部计算完成后,得到目标区域的平面位移场。室内块体移动试验表明该方法的计算精度受变形梯度的影响,在地表变化剧烈处会产生一定程度的误差,且子集相关性系数无法达到1。在黄藏寺滑坡的位移监测中,利用本方法识别出了边坡的变动区域,计算出了滑坡的平面位移场,直观地反映了滑坡表面变形状况,验证了该方法的实用性。 相似文献
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岩体结构面的剪切力学特性主要取决于其表面粗糙特征,结构面粗糙系数是表征该粗糙特征的主要方法。目前对结构面粗糙系数的研究局限于单一维度,多角度且定量化计算结构面粗糙系数能避免单一维度分析导致计算精度不准的局限性。采用立方体花岗岩,通过巴西劈裂的方式制备含结构面的试样;利用高精度三维扫描仪对试样结构面进行扫描,得到结构面的点云数据,同时借助逆向软件对点云数据进行三维重构。研究了点云数据Z方向上的分布频率,剖面线剖面比与节理粗糙系数（JRC）值的关系,结构面面积比与JRC均值的关系。研究表明：点云数据Z方向上的分布频率可以作为初步评估结构面粗糙度的手段;剖面线剖面比与JRC数值、结构面面积比与JRC均值有二次函数的关系。通过数值分析建立了结构面JRC均值与剖面比、面积比的二元函数关系,并得到结构面JRC均值的经验计算公式。本次研究为结构面粗糙度提供了一种“点-线-面”逐渐深入的多角度评估思路,得到的经验公式为计算结构面JRC均值提供了一种新的计算方法。 相似文献
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三维激光扫描技术在滑坡物理模型试验中的应用 总被引：3，自引：0，他引：3
大型滑坡物理模型试验中常采用高精度的特征点监测,缺少整体变形资料;而三维激光扫描技术可以高精度、快速、完整地扫描实物,获得海量的点云数据,构建实物的数字化模型,从而详细描述表面细部状况。将三维激光扫描技术引入到滑坡物理模型试验坡体表面整体变形监测中,通过数字仿真试验对点云数据4种变形测量方式进行了对比和评价,推导了点云数据单个扫描点的空间位置精度的评价模型,对点云密度进行了理论分析。通过滑坡物理模型试验实例,采用点云比较、重心法、点云叠加方法测量模型的整体变形和单个监测点的位移,对滑坡不同演化阶段变形特征进行了综合分析。研究表明:空间位置精度的评价模型、点云密度模型为三维激光扫描变形监测的测量成果评定,测量方案的优化设计提供了必要的理论基础。点云叠加、点云比较为面测量,可以获得整个模型坡面的变形和位移情况,测量模型的变形趋势和变形量级,重心法、拟合法则属于点测量,可以获得单个监测点准确的位移量。基于三维激光扫描技术坡面监测是结合点测量和面测量的优势,在保证高精度特征点监测同时,获得模型坡面的整体变形和位移。 相似文献
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层状复合岩体在隧道工程中随处可见,层理面的软弱性直接决定层状岩体隧道围岩的稳定性。为了揭示层理面对隧道围岩变形的影响规律,本文采用AutoCAD软件建立某隧道横断面,将该断面图导入有限元模拟软件ABAQUS中,并利用0厚度Cohesive单元对模型嵌入不同角度层理面,从而构建含不同层理面的隧道断面模型。基于该数值模型研究了层状隧道围岩变形中层理面角度的响应特征,得到从水平层理过渡到竖直层理的过程中,围岩变形区域也从顶部变化到侧壁。结合二次开发获取的声发射模拟数据,得到了不同层理面角度下的围岩易破裂区,针对该区域分布特征,隧道施工后可采用三维激光扫描技术生成点云数据,进行隧道断面的三维重构,为规避点云数据量庞大的缺点,引入分级重采样思想,对层状围岩易变形区进行局部点云细化,通过隧道断面易变形区点云模型的实时对比分析,实现隧道围岩的高效、精确化监测,可指导隧道围岩的安全稳定运营。 相似文献
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岩体结构特征控制着岩体力学性质并影响岩体工程稳定性,因此岩体结构地质编录一直是岩体工程地质中的重要内容。针对露天矿山边坡,传统的岩体结构编录方法具有危险性大、效率低等缺点,需要引入新技术实现地质编录的安全、高效。随着近年来无人机的民用化,采用无人机倾斜摄影技术改进传统露天矿坡的地质编录工作将成为未来的发展趋势。本文以浙江某露天采石场矿坡为例,阐述了无人机摄影技术在地质编录中的应用方法和工作流程。基于无人机倾斜摄影技术,采用运动恢复结构法将点云数据转化为岩体三维数字模型,并利用点云的坐标信息实现对岩体结构面产状的解译。通过对比罗盘测量的产状和点云计算的产状验证了该技术应用的可靠性。在此基础上划分了结构面的优势产状,为分析矿山边坡稳定性提供了基础数据支持。 相似文献
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基于理想点-可拓云模型的隧道围岩稳定性评价 总被引：1，自引：0，他引：1
为了对隧道围岩稳定性进行准确评价并解决研究过程中存在的模糊性和随机性以及评价指标不相容的问题,减少单一的主客观赋权法所带来的误差,将云模型引入可拓理论中,利用可拓理论能够实现矛盾问题向相容问题转化的特点和云模型具有处理事物双重不确定性的优势并结合理想点组合赋权法对隧道围岩进行稳定性评价研究。通过文献调研、数据统计的方式,选取具有代表性的6个指标组成隧道围岩评价指标体系,用理想点法赋予评价指标组合权重,并构建可拓云模型对隧道围岩稳定性进行综合评价。通过将此方法应用于工程实例并与其他方法对比,结果表明:基于理想点-可拓云模型的隧道围岩稳定性评价方法能够减少评价过程中存在的不确定性问题,克服单一赋权方法的不足,具有良好的适用性,可以应用于实际工程中。 相似文献
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在保证采空区几何特征不变的前提下,有必要对点云数据进行精简,提高三维建模及其应用的效率。介绍了点云数据精简算法的评价体系,探讨了空区探测系统扫测采空区的点云数据特点;在对比最小距离法、平均距离法、角度偏差法、弦高偏差法等采空区点云数据精简方法的基础上,提出了保留采空区几何特征更为有效的点云数据精简方法——改进的角度偏差法。通过对比精简前后的扫描线周长、面积及标准差等指标,认为该方法不但保持了扫描线的细节,而且使精简后扫描线上的点分布较均匀,为后续三维建模及应用打下良好基础。 相似文献
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准确、高效、全面获取岩体结构面信息,对岩体的稳定性分析有着重要的意义.采用三维激光扫描设备进行岩体数据采集,基于岩体点云模型提出了结构面自动识别方法.通过对Ransac算法进行改进,引入了新的采样方法和评分准则,大大提升了Ransac算法的计算效率和提取精度,使之更好地适应粗糙不平的岩体点云数据;基于改进的Graham Scan算法可以精准描绘出结构面的凸凹边界,进而精细化计算出结构面尺寸.基于以上算法研发了结构面识别程序RDD（ransac discontinuity dtection）,并且采用了两组标准几何体数据和一组岩体数据对程序进行测试.结果表明,标准几何体产状误差在1°以内,实际岩体最大误差在6°以内,结构面尺寸最大误差率为0.278%,满足工程限定的误差要求. 相似文献
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Landslides - We propose a novel fully automated deformation analysis pipeline capable of estimating real 3D displacement vectors from point cloud data. Different from the traditional methods that... 相似文献
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Terrestrial laser scanning survey in support of unstable slopes analysis: the case of Vulcano Island (Italy) 总被引：2，自引：1，他引：1
Marsella Maria D’Aranno Peppe J. V. Scifoni Silvia Sonnessa Alberico Corsetti Marco 《Natural Hazards》2015,76(1):443-469
Natural Hazards - The capability to measure at distance dense cloud of 3D point has improved the relevance of geomatic techniques to support risk assessment analysis related to slope instability.... 相似文献
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James N. Otoo Norbert H. Maerz Xialing Li Ye Duan 《Rock Mechanics and Rock Engineering》2013,46(3):543-554
Light detection and ranging (LiDAR) scanners are increasingly being used to measure discontinuity orientations on rock cuts to eliminate the bias and hazards of manual measurements which are also time consuming and somewhat subjective. Typically LiDAR data sets (point clouds) are analyzed by sophisticated algorithms that break down when conditions are not ideal, for example when some of the discontinuities are obscured by vegetation, or when significant portions of the rock face are composed of fractured facets, weathering generated surfaces, or anything that should not be identified as a discontinuity for the purposes of slope stability analysis. This paper presents a simple LiDAR point cloud viewer that allows the user to view the point cloud, identify discontinuities, pick three points on the surface (plane) of each discontinuity, and generate discontinuity orientations using the three-point method. Additionally, a test of our 3-D LiDAR viewer for discontinuity orientations on rock cuts in the United States of America and Canada is presented. 相似文献
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A. M. Ferrero G. Forlani R. Roncella H. I. Voyat 《Rock Mechanics and Rock Engineering》2009,42(4):631-665
The location and orientation of rock discontinuities, which are traditionally obtained from geological surveys with obvious
drawbacks (safety, rock face accessibility, etc.), may also be derived from a detailed and accurate photogrammetric or laser
scanning survey. Selecting from the point cloud determined on the rock face a set of points distributed on a particular discontinuity,
location, dip, and dip direction can be computed from the least-squares estimate of the plane interpolating the set of points.
Likewise, the normal vector to the surface may be computed from an interpolation or approximation of the surface by appropriate
functions. To become a real alternative (both in terms of productivity as well as accuracy) to a traditional survey, interactive
or automated software tools are necessary, to allow the efficient selection of the point sets on the discontinuities or the
interpretation of the normal vector pattern. After introducing the two best technologies available today for data acquisition
and their performance, the paper presents an approach, based on the random sample consensus (RANSAC) procedure, to the segmentation
of the point cloud into subsets, each made of points measured on a discontinuity plane of the rock face. For each subset,
the plane’s equations coefficients are first determined by robust estimation and then refined by least-squares estimation
after outlier removal. The segmentation algorithm has been implemented in RockScan, a software tool developed to facilitate
the interaction with the point cloud in the identification of the discontinuities; rather than using the three-dimensional
(3D) data, selection of regions of interest is performed on oriented images of the rock face. Finally, application of RockScan
to four different test sites is discussed and results presented. The sites differ in size (from tens to hundreds of meters),
rock surface characteristics, and the technology used to produce the point cloud (in three cases photogrammetry, in the fourth
laser scanning), giving the opportunity to test the methodology in different contexts. In the first and in the fourth site
an extensive traditional survey has been performed, providing reference data to validate the RockScan results. 相似文献
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智能化、无人化开采是煤炭行业发展的必然趋势,精准地质信息探测是当前智慧煤矿建设中的重点研发方向之一,其中巷道信息的精准探测和巷道三维模型的快速获取是地质透明化的重要数据来源。对比分析传统巷道建模方法及其优缺点,提出利用三维激光扫描重建技术构建高精度透明工作面巷道模型的技术思路。在分析煤矿井下工况环境长距离三维激光扫描面临的技术难题的基础上,研究三维激光扫描原理和空间点坐标计算方法,并提出透明工作面巷道三维激光扫描重建技术流程,其关键技术包括:三维激光扫描系统动态标定和坐标转换方法;点云预处理技术中基于统计滤波法的大尺度噪声滤波方法和基于移动最小二乘的小尺度噪声滤波算法;点云关键点提取与特征描述技术中SIFT特征检测算法和FPFH特征描述算法;点云配准技术中基于FPFH特征描述算法的粗配准技术和基于迭代最近点算法的精配准技术。以准格尔煤田唐家会煤矿某工作面为研究对象,利用自主研发的移动式三维激光扫描系统从三维激光扫描施工流程、巷道点云数据采集、边界轮廓线提取、巷道与工作面联合建模等方面进行实践应用。结果表明,提出的基于三维激光扫描技术的工作面巷道三维重建思路在技术上是可行的,能为复杂巷道的快速三维扫描、重建提供一条可行的技术路径。 相似文献
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Mansour S. Alhumimidi Mohammed S. Alfarhan Jarvis R. Cline Carlos L. V. Aiken 《Arabian Journal of Geosciences》2017,10(5):112
Three dimensional (3D) photorealistic models of geological outcrops have the potential to enhance the teaching of earth sciences by providing scale models in a virtual reality environment. These models can be run on low-cost desktop computers. Photorealistic models for geological outcrops are a digital illustration of outcrop photographs with either a point cloud representation or Triangular Irregular Network (TIN) mesh of the outcrop surface. The level of detail for these models is dependent on the target resolutions (physical and optical) that were used during data acquisition. In addition, the technique in which the data is rendered as a digital model affects the level of detail that can be observed by the geologists. A colored point cloud representation is suitable for large-scale features, but fine details are lost when the geologist zooms in to view the model close up. In contrast, a photorealistic model that is constructed from photographs draped onto a triangle mesh surface derived from Light Detection and Ranging (LiDAR) point clouds provides a level of detail that is restricted only by the resolution of the photographs. 相似文献
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岩体隧洞结构面的数量、产状和发育情况是评价隧洞透水性和稳定性的重要指标。采用三维激光测量技术可以快速获取隧洞周围岩体激光点云数据和结构面的几何信息。提出了基于柱面投影和Delaunay生长算法的激光点云的三角网重构技术,利用构建的三角网平面方程的法向向量计算出单个三角网平面的产状,并应用FKM聚类算法进行隧洞岩体结构面产状的模糊群聚分类。该方法可以快速得到不同组的优势产状,且分类结果可用不同颜色进行空间显示。最后运用自主研发的FSS软件对某隧洞的岩体结构面优势产状进行了研究,研究结果表明：1）基于柱面投影和Delaunay生长法的点云构网方法特别适合于隧洞工程,构网速度快、效率高,重构得到的三角网表面与被采样的岩体表面拓扑差别最小;2）FKM模糊群聚方法对隧洞岩体结构面的群聚分类结果可靠、合理,具有较强的通用性和推广性。 相似文献
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提出了基于CT扫描技术和PFC三维颗粒流程序建立含砾滑带土三维建模方法。首先,通过CT扫描技术获得含砾滑带土三轴试样的一系列二维切片图像,采用二值化和砾石边界识别方法,得到了砾石边界点云数据;其次,利用砾石边界点云数据,采用逆向重构得到各个砾石的三维模型;最后,将重构的三维砾石模型导入PFC三维颗粒流程序,建立颗粒流数值模型。计算结果表明:三轴剪切过程中,砾石的欧拉角随着试样剪切变形的发展而变化;与无砾石试样相比,砾石周围土体小球的运动方向更加杂乱,说明了砾石对含砾滑带土的剪切破坏有显著的影响。通过与三轴剪切试验过程中砾石的空间运动规律进行对比分析,验证了提出的建模方法是可行的。采用该方法研究砾石的空间运动特征,对于揭示砾石在含砾滑带土剪切破坏过程中的作用具有重要的意义。 相似文献
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《Comptes Rendus Geoscience》2019,351(7):508-516
Terrestrial laser scanning (TLS) is widely used because of its ability to quickly acquire high-density and high-precision 3D image and topographic data. However, it can only acquire independent coordinate system points, which restricts its application in large-scale deformation monitoring. In this study, we constructed a measurement system to acquire global coordinate point cloud data by combining TLS and GPS (Global Positioning System). The coordinate values of retro-reflective targets could be acquired in different coordinate systems, the GPS coordinate and the TLS station coordinate, synchronously. Our experiments showed that, after registration with the homonymy points acquired by 30-min short-baseline differential GPS using the ICP algorithm, the positional accuracy of the TLS retro-reflective target center in the global coordinate was better than 10 mm. This high precision meets, for instance, the requirements of coal mining subsidence monitoring. We used our new combined measurement system to acquire and process the point cloud data of a frame structure. The measurements demonstrated the practicability and robustness of the new measurement system. 相似文献
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Fracture network modeling is an essential part of the design, development and performance assessment of Enhanced Geothermal Systems. These systems are created from geothermal resources, usually located several kilometers below the surface of the Earth, by establishing a network of connected fractures through which fluid can flow. The depth of the reservoir makes it impossible to make direct measurements of fractures and data are collected from indirect measurements such as geophysical surveys. An important source of indirect data is the seismic event point cloud generated by the fracture stimulation process. Locations of these points are estimated from recorded micro-seismic signals generated by fracture initiation, propagation and slip. This point cloud can be expressed as a set of three-dimensional coordinates with attributes, for example Se ijk ={(x,y,z);?a|x,y,z∈R,?a∈I}. We describe two methods for reconstructing realistic fracture trace lines and planes given the point cloud of seismic events data: Enhanced Brute-Force Search and RANSAC. The methods have been tested on a synthetic data set and on the Habanero data set of Geodynamics’ geothermal project in the Cooper Basin of South Australia. Our results show that the RANSAC method is an efficient and suitable method for the conditional simulation of fracture networks. 相似文献