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1.
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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《岩土力学》2017,(1):291-299
将红外辐射成像技术引入滑坡物理模型试验中,通过红外热像仪与三维激光扫描仪所搭建的监测系统,对滑坡模型坡体表面变形破坏全过程进行温度与位移的监测。基于滑坡表面监测数据,将原始红外热像监测图形进行数据修正与差值处理,采用处理后获得的温度场数据,将其与模型坡表位移演化规律进行对比分析。结果表明,滑坡模型在进入加速变形阶段前,潜在破裂区域温度随荷载的增大而均匀上升,破裂带内、外温差较小;滑坡模型进入加速变形阶段后,会在潜在破裂区域的红外热像上出现条形的高温异常区域,破裂区域的破裂带内、外温差迅速拉大,两者相差最高为0.49°C,整体滑动失稳前夕,平均红外辐射温度-时间曲线上再表现出破裂带内温度陡增后降低的规律。研究结果表明,红外热像技术可以应用于滑坡模型试验,利用温度可对滑坡进行预测预报提供参考。 相似文献
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为分析白龙江流域舟曲段江顶崖滑坡的变形演化机理及其阈值,设计降雨条件下的大型堆积体滑坡物理模型试验,采用FARO FocusS 350三维激光扫描仪进行滑坡数据采集、处理,获取滑坡在不同降雨工况的点云模型数据,对比分析不同降雨工况下滑坡宏观及局部特征点的变化情况。研究表明：滑坡模型表面出现持续、快速、变化鲜明的整体变形特征,伴随出现滑坡模型中、前部横向、纵向的张拉裂缝,表明在非饱和渗流影响下,堆积体滑坡模型的基质吸力降低、孔隙水压力以及滑坡体重力荷载增加,导致滑坡模型临近失稳;根据滑坡模型宏观变形情况,其变形演化过程可划分为：初始变形阶段、等速变形阶段和加速变形阶段,3个不同变形阶段坡体宏观变形各自有其特点。通过对试验阶段的变形特征分析,设立了滑坡变形速率阈值,分别为0.01 m/h、0.02 m/h、0.2 m/h。基于三维激光扫描技术坡体监测,结合坡体变形宏观和局部分析的优势,在保证高精度监测、采集、处理的同时,得到坡体的整体变形和位移。 相似文献
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《岩土力学》2020,(9)
常规的可视化模型试验中,能够观察到二维观测视窗中的位移变形,但是却无法获取三维问题的离面位移以及三维空间变形场。为此,基于透明土模型试验,自主开发了一套自动层析扫描测试装置,通过高精度电动线性平台控制着相机和激光器同步运动,获取一系列二维图片。利用改进的图像变形测量方法进行图像后处理。在此基础上,自主编写了相应的三维重构的体绘制程序,用于构建变形后的三维位移场。为了验证空间变形可视化测量系统的可行性,开展了方形基础和圆形基础透明土静压试验。试验结果表明:重构后的三维竖向位移和水平位移等值面云图的变化规律和理论预测结果以及前人文献中所提到的规律一致,三维矢量位移场可以直观地显示不同位置的土体运动规律,能弥补二维观测技术不能反映离面位移的局限性。该研究不仅可以进一步地揭示静压试验中的三维空间变形问题,同时还证明该方法对于实现物理模型试验中观测三维空间变形问题是可行的。 相似文献
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采用模型试验是研究滑坡及其抗滑结构的一种有效方法,红外热像仪在滑坡模型试验中的应用是基于红外检测和热成像原理,利用红外热像仪对滑坡模型抗滑桩区域坡表温度进行有效、准确、实时地检测并记录,有助于分析滑坡破坏过程中抗滑桩所在区域温度场的变化规律,从能量的角度对抗滑桩土拱效应进行研究。试验结果揭示了滑坡抗滑桩区域温度场的分布规律,从温度场方面证实了土拱效应的存在,并揭示了土拱形成过程及其机制;抗滑桩有效地阻止了滑坡推力向桩前发展,发挥了抗滑效果;滑坡发生过程中岩土体应力场、位移场和能量变化是息息相关的。红外热成像技术的应用为抗滑桩土拱效应的研究提供了一种新的研究方法,使得从能量变化的角度研究抗滑桩等防治结构作用机制成为可能,其可行性和可靠性在模型试验中得到了验证。 相似文献
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中国黄土高原滑坡灾害频发,且大多与降雨有关,而节理构造是导致黄土滑坡发生的重要因素之一。为进一步揭示节理对黄土滑坡的影响作用,本文以节理为研究切入点,基于实地考察,开展了预设节理工况下降雨诱发滑坡的大型物理模型试验。通过实时监测模型边坡内部土体含水率和孔隙水压力等指标参数随降雨过程的阶段性变化,分析了边坡内部节理裂隙的扩张与演化趋势,以及坡体位移和形变特征,对比揭示了节理的存在对于诱发滑坡的潜在机制及坡体响应规律。试验结果表明:节理对雨水在坡体内部的入渗具有明显的加速和促进作用,预设节理侧的边坡相对于不含节理侧,其土体含水率增速更快、增幅更大且影响范围更广;位于模型边坡中部的节理裂隙的张开度最大,含节理侧坡体的裂隙张开度约为不含节理侧的2倍,滑坡发生时,含节理侧的孔隙水压力的上升幅度相对较大;土体含水率对降雨的敏感度和变化幅度与埋深成反比,坡体浅表部含水率的响应较快且波动较大,而深部则相反。研究结果可为进一步厘清黄土滑坡的成因及破坏机理提供试验依据和理论参考。 相似文献
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《中国煤炭地质》2017,(8)
以G104国道丁山服务区西侧滑坡为研究对象,根据勘查和室内试验结果,结合反演方法确定滑坡滑带土强度参数。设定了降雨入渗模型、建立滑坡体数值模型,运用非饱和土渗流理论对边坡进行渗流场和应力场耦合分析。通过有限元方法模拟降雨96h,对孔隙水、渗流、位移和边坡稳定性分析。结果表明:降雨过程中,孔隙水压力与坡体位移有明显相关性,坡顶X分量位移较大,坡体的浅层、坡体上部孔压及位移变化较大,因而容易引发后缘拉裂缝、浅层滑塌,降雨后期坡体持续蠕移,引发边缘剪切裂缝,进而诱发整体性滑坡。削坡和挡墙能够提高坡体稳定性,格构、绿化、截排水工程能够减小降雨对坡顶稳定性的影响。 相似文献
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推移式滑坡演化过程模型试验与数值模拟研究 总被引：1，自引：0，他引：1
利用MTS电液伺服加载与控制系统对推移式滑坡物理模型后缘进行了分级推力加载,完成了推移式滑坡演化全过程的模拟。基于三维激光扫描技术对滑体表面的位移和变形进行了高精度、全方位、非连续性监测。采用多重分形基本理论对监测点云数据进行了系统分析,从试验的角度探讨了推移式滑坡演化过程中位移多重分形维数的变化特征。模型试验结果表明：推移式滑坡变形破坏以沿滑带发生的整体滑移为主,并表现出明显的演化阶段性特征,大致可划分为3个阶段：（1）后缘压缩阶段：滑坡模型表面变形体现为后缘土体的局部前移与隆起,整体变形小,多重分形维数成降维的特征,降维过程中未发生突变、有序性好;（2）匀速变形阶段：滑坡模型表面产生了明显的位移,变形不断向前和向两侧发展,前缘、中部滑体发生隆起现象,多重分形维数表现出先减后增的趋势;（3）加速变形阶段：滑坡模型表面体现出持续、快速、变化鲜明的整体变形特征,伴随出现滑坡模型中前部隆起带及横向、纵向的隆胀裂缝,多重分形维数成增维趋势。基于模型试验,利用FLAC3D进行了推移式滑坡演化过程的动态数值模拟,验证了滑坡演化的阶段性特征,揭示了推移式滑坡演化过程中稳定性系数非线性递减的规律。 相似文献
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基于三维激光扫描的滑坡变形监测与数据处理 总被引：8，自引：0，他引：8
地面三维激光扫描技术可以高精度、高密度、高速度地测量物体表面三维空间坐标,从而详细描述表面细部状况。它已经在静态形状测量中获得了成功的应用。目前,滑坡地表变形分析主要是采用GPS或全站仪测量的少量特征点来进行,缺乏整体变形资料。但滑坡变形体的诸多细节变化对正确的变形分析有着重要的作用,将该技术引入到滑坡变形监测与分析中,可充分利用滑坡体上的大量点自然地物作为监测点,来完整监测和分析其变形。作为一项新的研究内容,文章对此进行了相应的理论分析与实际测量,获得了初步满意的结果。 相似文献
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顺层岩质滑坡是最常见的斜坡灾害,研究其渐进破坏过程、建立预报判据对于防灾减灾具有重要意义.以秭归杉树槽滑坡为例,在野外调查和室内岩石试验的基础上,利用JRC-JCS模型及GSI法估算得出滑坡基本力学参数;通过FLAC3D模拟滑坡渐进破坏过程,分析顺层岩质滑坡变形破坏的发展规律;基于能量守恒和虚功原理,提出了顺层岩质滑坡迈入加速变形的能量学判据.研究表明:杉树槽滑坡由后缘向前渐进破坏,后缘变形累积的总位移值不断增大,前缘切层段的锁固作用使变形迅速降低,当临近破坏时,前缘位移由前向后发展,滑面快速贯通;滑体沿滑动方向应变曲线可近似表示为"S"型曲线,随渐进破坏该曲线向坡下发展;以滑体动能增量大于0作为滑坡迈入加速变形的能量学判据,其结果符合滑坡地质演化观点,与FLAC3D模拟结果吻合. 相似文献
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Interferometric synthetic aperture radar (InSAR) analysis is a radar technique for generating large-area maps of ground deformation using differences in the phase of microwaves returning to a satellite. In recent years, high-resolution SAR sensors have been developed that enable small-scale slope deformation to be detected, such as the partial block movement of a landslide. The L-band SAR (PALSAR-2) is mounted on Advanced Land Observing Satellite-2 (ALOS-2), which was launched on 24 Mar. 2014. Its main improvements compared with ALOS are enhanced resolution of as high as 3 m with a high-frequency recurrence period (14 days). Owing to its high resolution and the use of the L-band, PALSAR-2 can obtain reflective data passing through a tree canopy surface, unlike the other synthetic aperture radars. Therefore, the coherence of InSAR in mountainous forest areas is less likely to decrease, making it advantageous for the extraction of slope movement. In this study, to verify the accuracy of InSAR analysis using PALSAR-2 data, we compared the results of InSAR analysis and the measurement of the displacement in a landslide by global navigation satellite system (GNSS) observation. It was found that the average difference between the displacements obtained by InSAR analysis and the field measurements by GNSS was only 15.1 mm in the slant range direction, indicating the high accuracy of InSAR analysis. Many of the areas detected by InSAR analysis corresponded to the locations of surface changes due to landslide activity. Additionally, in the areas detected by InSAR analysis using multiple datasets, the ground changes due to landslide movement were confirmed by site investigation. 相似文献
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It has been known that ground motion amplitude will be amplified at mountaintops; however, such topographic effects are not
included in conventional landslide hazard models. In this study, a modified procedure that considers the topographic effects
is proposed to analyze the seismic landslide hazard. The topographic effect is estimated by back analysis. First, a 3D dynamic
numerical model with irregular topography is constructed. The theoretical topographic amplification factors are derived from
the dynamic numerical model. The ground motion record is regarded as the reference motion in the plane area. By combining
the topographic amplification factors with the reference motions, the amplified acceleration time history and amplified seismic
intensity parameters are obtained. Newmark’s displacement model is chosen to perform the seismic landslide hazard analysis.
By combining the regression equation and the seismic parameter of peak ground acceleration and Arias intensity, the Newmark’s
displacement distribution is generated. Subsequently, the calculated Newmark’s displacement maps are transformed to the hazard
maps. The landslide hazard maps of the 99 Peaks region, Central Taiwan are evaluated. The actual landslide inventory maps
triggered by the 21 September 1999, Chi-Chi earthquake are compared with the calculated hazard maps. Relative to the conventional
procedure, the results show that the proposed procedures, which include the topographic effect can obtain a better result
for seismic landslide hazard analysis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Junqi Liu Huiming Tang Junqiang Zhang Tingting Shi 《Environmental Earth Sciences》2014,72(10):3847-3856
As the global research topic, geological disasters have led to huge losses around the world yearly. In this paper, three-dimensional (3D) visualization is used as a technical method to build the 3D geological model of the HuangTuPo (HTP) landslide, and the 3D model of large field test base located in the HTP landslide, and the 3D regional geological model. These models make the landslide research digitized and transparent. Meanwhile, the preliminary studies were carried out: the comprehensive utilization of multiple scales and multiple categories of data—by “Double Center”, and the 3D data integration from region to point of disasters—by the component technology, and the transparent design and construction of disaster research—by 3D model shearing. Through these methods, the surface topography and the underground geological structure of landslide can be displayed as transparent as glass, and the virtual simulation on the results of underground engineering can be carried out in advance, providing guidance for engineering design and construction. 相似文献
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《地学前缘(英文版)》2022,13(3):101378
Frequent soil landslide events are recorded in the Three Gorges Reservoir area, China, making it necessary to investigate the failure mode of such riverside landslides. Geotechnical centrifugal test is considered to be the most realistic laboratory model, which can reconstruct the required geo-stress. In this study, the Liangshuijing landslide in the Three Gorgers Reservoir area is selected for a scaled centrifugal model experiment, and a water pump system is employed to retain the rainfall condition. Using the techniques of digital photography and pore water pressure transducers, water level fluctuation is controlled, and multi-physical data are thus obtained, including the pore water pressure, earth pressure, surface displacement and deep displacement. The analysis results indicate that: Three stages were set in the test (waterflooding stage, rainfall stage and drainage stage). Seven transverse cracks with wide of 1–5 mm appeared during the model test, of which 3 cracks at the toe landslide were caused by reservoir water fluctuation, and the cracks at the middle and rear part were caused by rainfall. During rainfall process, the maximum displacement of landslide model reaches 3 cm. And the maximum deformation of the model exceeds 12 cm at the drainage stage. The failure process of the slope model can be divided into four stages: microcracks appearance and propagation stage, thrust-type failure stage, retrogressive failure stage, and holistic failure stage. When the thrust-type zone caused by rainfall was connected or even overlapped with the retrogressive failure zone caused by the drainage, the landslide would start, which displayed a typical composite failure pattern. The failure mode and deformation mechanism under the coupling actions of water level fluctuation and rainfall are revealed in the model test, which could appropriately guide for the analysis and evaluation of riverside landslides. 相似文献
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基于集对分析的滑坡变形动态建模研究 总被引：4，自引：1，他引：3
滑坡是一个确定-不确定的动态系统,其变形表现出复杂的非线性演化特征。为了克服传统分析方法在处理系统不确定性方面的不足,将集对分析法（SPA）引入岩土变形监测分析领域,并结合层次分析法（AHP）提出了滑坡变形动态预测模型,给出了基于概率论的最优预测算法,提出并证明了集对论中最大同一度在等势条件下存在极限解,据此提出位移势的概念。在位移势的基础上,进行SPA二次建模,提出了基于SPA的滑坡变形与水库蓄水过程相关性动态分析模型。运用上述预测模型对新近发生的刘家沱滑坡进行变形监测定量分析,实践证明：最优预测值具有良好的短期预报精度;位移势能够表征系统当前状态下位移所能达到的最大潜力,可作为短期预测的上限值,其变化能够反映系统宏观层面上的演化特征,对滑坡演变加速预警具有指导意义;运用集对分析方法进行滑坡变形响应滞后效应的定量研究是一条可行的新思路,反演结果与实际情况吻合;该方法在岩土监测分析领域有良好的应用前景。 相似文献