Three-dimensional Laser Scanning Data Research Articles

The safety factor of a heterogeneous slope in an open-pit metal mine: A case study from the Tanjianshan gold mine

A landslide of the north open-pit (323N) and the stability and design optimization of the south open-pit (323S) slope in the 323 belts of the Tanjianshan Gold Mine were studied. On 14 September 2020, a large landslide occurred on the east side of 323N, which posed a severe threat to the safety production of the mine. To avoid a similar slide on the south open-pit in the 323S, the limit equilibrium method was used to estimate the stability of the final slope of the designed initially open-pit in the 323N. The results show that the location and scale of the landslide are in good agreement with the three-dimensional laser scanning data. The effectiveness of the limit equilibrium method in slope stability analysis of the Tanjianshan Gold Mine was validated. The stability of the final slope of the initial design of 323S was analyzed. The sensitivity of the safety factor of homogeneous slope and heterogeneous rock slope to the bench face angle (BFA) and the difference of landslide type were compared and studied. When the spatial geometric relationship of rock masses with different lithology is complex, the engineering analogy method is inapplicable to calculation of parameters such as the BFA of heterogeneous rock slope and overall slope angle of the open-pit. The slope safety factor should be checked, and the slope step parameters are warranted to be optimized. The safety and economic benefits of the slope can be improved.

Intelligent identification of rock mass structural plane and stability analysis of rock slope block

The blocking problem caused by structural plane cutting is often the primary problem in evaluating the stability of rock mass engineering. The geometric parameters of the block structural plane are important research bases for analyzing block stability. In order to solve the problems of low efficiency, heavy workload, and high subjectivity in the traditional acquisition of structural plane occurrence information, taking the slope at the entrance of Suichang Gold Mine National Mine Park as the research background, this paper studies the rapid extraction method of structural plane information based on three-dimensional laser scanning data, and puts forward the process and data processing method of using a 3D laser scanner to collect slope block structural information to obtain point cloud data. Based on the coordinate projection principle and MATLAB, the rock slope block stability analysis CPG program was developed, which realized the whole process from data acquisition to block stability analysis. The research results are essential for identifying structural plane and block stability analysis and can provide theoretical and technical support for practical engineering applications.

Calculation model for ventilation friction resistance coefficient by surrounding rock roughness distribution characteristics of mine tunnel

Real-time mine ventilation network solution is the core way to realize the actual intelligent ventilation, and ventilation friction resistance coefficient is a significant parameter of network solution. With the help of fractal theory to characterize the three-dimensional roughness characteristics of tunnel surrounding rock. A method to describe the roughness by fractal dimension and fractal intercept. We put the fractal dimension and fractal intercept into Matlab to randomly generate three-dimensional laser scanning data of tunnels. The fusion of the two fractal parameters made the three-dimensional roughness surface information more comprehensive. It has been applied to field practice accurately. Compared to the simulation results show that the relative error of the new prediction results is 3%. Comprehensive evaluation analysis shows that the new friction wind resistance formula can fully reflect the influence of three-dimensional rough surfaces on airflow friction resistance. With the help of three-dimensional laser scanning technology, we can calculate the airflow friction resistance of the tunnel quickly and accurately, which provides a reference for the development of key technology and the theory of intelligent ventilation parameter measurement.

Automatic extraction of tunnel centerline and cross-sections from 3D point clouds

The accurate extraction of tunnel centerline and tunnel cross-section plays a vital role in many tunnel deformation monitoring projects. To address this issue, An automatic data extraction method for a tunnel centerline and cross-section is proposed based on the three-dimensional laser scanning data. A k-dimensional tree index is first constructed based on the horizontal projection of the tunnel point clouds, and then a series of seed points is selected as the center of several neighborhood point sets with different radii; the difference set region, which will be used to calculate the tunnel horizontal centerline point based on the convex hull operation, is obtained. Then, according to the horizontal centerline, the cross-section of the tunnel point clouds is extracted and fitted to obtain the tunnel cross-section parameters and three-dimensional centerline. Based on the design values of the three-dimensional centerline and tunnel radius, the overall model of the tunnel can be constructed and applied to the visual analysis of tunnel deformation. The experimental results show that the proposed method can accurately obtain the tunnel centerline and cross-section parameters, with a minimal 0.011 cm error for the extraction of the horizontal centerline. The proposed tunnel model could simulate the undulation of the tunnel surface well and provide reference values for similar cases.

Modeling Vehicle Collision Angle in Traffic Crashes Based on Three-Dimensional Laser Scanning Data.

In road traffic accidents, the analysis of a vehicle’s collision angle plays a key role in identifying a traffic accident’s form and cause. However, because accurate estimation of vehicle collision angle involves many factors, it is difficult to accurately determine it in cases in which less physical evidence is available and there is a lack of monitoring. This paper establishes the mathematical relation model between collision angle, deformation, and normal vector in the collision region according to the equations of particle deformation and force in Hooke’s law of classical mechanics. At the same time, the surface reconstruction method suitable for a normal vector solution is studied. Finally, the estimation model of vehicle collision angle is presented. In order to verify the correctness of the model, verification of multi-angle collision experiments and sensitivity analysis of laser scanning precision for the angle have been carried out using three-dimensional (3D) data obtained by a 3D laser scanner in the collision deformation zone. Under the conditions with which the model has been defined, validation results show that the collision angle is a result of the weighted synthesis of the normal vector of the collision point and the weight value is the deformation of the collision point corresponding to normal vectors. These conclusions prove the applicability of the model. The collision angle model proposed in this paper can be used as the theoretical basis for traffic accident identification and cause analysis. It can also be used as a theoretical reference for the study of the impact deformation of elastic materials.

Pair-wise automatic registration of three-dimensional laser scanning data from historical building by created two-dimensional images

Registration of a point cloud is a great challenge in the process of laser scanning data. So far, many registration methods have been introduced by range data, integrated camera image, and a combination of them. Moreover, the automatic registration of three-dimensional point clouds is an important research topic in both geomatics and computer sciences. In this study, keypoint-based registration of point clouds was introduced. Intensity images were created from the laser scanning data, and then a pair-wise automatic registration was performed with the keypoints extracted from the intensity images by a scale invariant feature transform (SIFT) and affine SIFT (ASIFT). The results were compared with the iterative closest point, which has high accuracy and is the extensively adopted method for the pair-wise registration. Consequently, SIFT and ASIFT keypoints which were extracted from intensity images can be exploited to pair-wise automatic registration of the point clouds.