scholarly journals Stability Analysis of Irregular Cavities in Tunnel Using Geomagic-COMSOL Coupling Method

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shangqu Sun ◽  
Chengshuai Qin ◽  
Hongbo Wang ◽  
Liping Li ◽  
Yongliang Huang
Keyword(s):  
Stability Analysis ◽  
Plastic Strain ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Point Clouds ◽  
Computational Error ◽  
Geometrical Shape ◽  
Scanning Method ◽  
The Stability

The erosion of soluble rock and transformation of groundwater result in the high irregularity of cavities in tunnel. At present, however, karst cavities are mainly simplified as circular, rectangular, or elliptical shape in the numerical simulation. The purpose of this paper is to propose a new method to analyze the stability of irregular cavities. First of all, we used the drilling laser scanning method to reconstruct the three-dimensional point clouds model of irregular cavities. Furthermore, we proposed the method of determining the point density to reduce the computational error under the premise of ensuring the accuracy in engineering scale. We also developed the Geomagic-COMSOL coupling numerical method to conduct the stability analysis of irregular cavities. The results demonstrated that the geometrical shape of karst cavities has great effects on the deformation and mechanical properties of the surrounding rock. The displacement and equivalent plastic strain of simplified cavities exhibited symmetric characteristics, while those of irregular cavities are highly randomly distributed. We noted that a greater displacement value and more intensive plastic strain can be triggered by irregular cavities shape, compared with the simplified cavity shape. The results also showed that the larger displacement occurred at the long-edge part, while the plastic zone was concentrated at the sharp turning angle of the irregular cavities.

Stability Analysis on Surrounding Rockmass of Deep Tunnel Based on YAI and FD Concepts

2007 ◽  
Vol 353-358 ◽  
pp. 2703-2706
Author(s):  
Hui Zhou ◽  
Chuan Qing Zhang ◽  
Xia Ting Feng ◽  
Bing Rui Chen
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Plastic Strain ◽  
Equivalent Plastic Strain ◽  
The Other ◽  
Accurate Estimation ◽  
Deep Tunnel ◽  
Stress States ◽  
The Stability

This paper proposes two concepts in order to estimate the stability of surrounding rockmass of deep tunnel, one is YAI (yielding approach index) which is used to denote the stability difference among the zones in surrounding rockmass whose stress states are close to yielding, the other is FD (failure degree) which focuses on the estimation of failure degree of the zones in surrounding rockmass and can be calculated by the equivalent plastic strain when failure occurs. Finally, a numerical analysis on the excavating process of a deep tunnel is performed, and YAI and FD are used to estimate the stability states of rockmass. The accurate estimation on plastic field and the proper evaluation on stability state indicate that these two concepts are rational and of perfectly practical use.

Progressive Deformation on Defective Pile Reinforced Slope

2017 ◽  
Vol 873 ◽  
pp. 248-253
Author(s):  
Shi Wei Hou ◽  
Shi He Ma ◽  
Xu Li Liu ◽  
Ying Liu
Keyword(s):  
Plastic Strain ◽  
Slope Failure ◽  
Progressive Failure ◽  
Failure Process ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Soil Arching ◽  
Reinforced Slope ◽  
Stress Curve ◽  
The Stability

The slopes reinforced by anti-slide piles were simulated in this paper. The setting position, pile spacing and anchorage depth of integrated piles were discussed with strength reduction method. The results show that the pile position should depart slope into two stages, and the further strain would be limited. When the spacing of the anti-slide piles is 2-3 times of pile diameter, it has a soil arching effect to wedge the soil. The anchorage depth can affect the form of the potential sliding surface. Three kinds of defective piles were studied to research deformation of slope reinforced by defective piles. The defective piles were namely expanded pile, necking pile and segregationpile. The equivalent plastic strain zone was used to judge the slope failure, and then the stability and deformation process of the three-dimensional slope were simulated. By comparing the plastic strain, safety coefficient curve and pile-soil stress curve, between the defective pile and integrated pile, the progressive failure process of the reinforced slope was analyzed, including the formation process of the macroscopic shear zone.

scholarly journals The stability study of goaf based on C-ALS data point cloud and FLAC3DCoupled modeling

2021 ◽  
Vol 261 ◽  
pp. 03053
Author(s):  
Huihui Jia ◽  
Jianzhi Xue
Keyword(s):  
Stability Analysis ◽  
Point Cloud ◽  
Laser Scanning ◽  
Safety Management ◽  
Three Dimensional ◽  
Mining Area ◽  
Stability Study ◽  
Ground Pressure ◽  
Data Point ◽  
The Stability

Through drilling and three-dimensional scanning by C-ALS laser, the spatial position and size of mined-out area can be obtained. It can provide important technical basis for safety management and evaluation of goaf. This paper takes the stability analysis of Hidden Goaf in the third mining area of Zhoutaizi Iron Mine, Zhangbaiwan town, Luanping County as an example. After the mined-out area was drilled, the data point cloud was obtained by C-als three-dimensional Laser scanning and the three-dimensional visualization model was constructed. Write the conversion program in FISH language and import it into FLAC3D, The distribution characteristics of ground pressure, deformation, failure of surrounding rock and surface subsidence in goaf are analyzed. And it is consistent with the actual situation of the goaf, Thus it shows the feasibility of the coupling modeling technology method of C-ALS data point cloud and FLAC3D in obtaining three-dimensional feature information of goaf and determining the stability of goaf. At the same time it provides technical reference for prospecting and stability analysis of similar goaf.

Measurement of erosion state and refractory lining thickness of blast furnace hearth by using three-dimensional laser scanning method

2020 ◽  
Vol 118 (1) ◽  
pp. 106
Author(s):  
Lei Zhang ◽  
Jianliang Zhang ◽  
Kexin Jiao ◽  
Guoli Jia ◽  
Jian Gong ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Laser Scanning ◽  
Refractory Lining ◽  
Three Dimensional ◽  
3D Laser Scanning ◽  
Scanning Method ◽  
Blast Furnace Production ◽  
Severe Erosion ◽  
Residual Thickness ◽  
Minimum Depth

The three-dimensional (3D) model of erosion state of blast furnace (BF) hearth was obtained by using 3D laser scanning method. The thickness of refractory lining can be measured anywhere and the erosion curves were extracted both in the circumferential and height directions to analyze the erosion characteristics. The results show that the most eroded positions located below 20# tuyere with an elevation of 7700 mm and below 24#–25# tuyere with an elevation of 8100 mm, the residual thickness here is only 295 mm. In the circumferential directions, the serious eroded areas located between every two tapholes while the taphole areas were protected well by the bonding material. In the height directions, the severe erosion areas located between the elevation of 7600 mm to 8200 mm. According to the calculation, the minimum depth to ensure the deadman floats in the hearth is 2581 mm, corresponding to the elevation of 7619 mm. It can be considered that during the blast furnace production process, the deadman has been sinking to the bottom of BF hearth and the erosion areas gradually formed at the root of deadman.

Analysis of Plastic Strain between Substrate and Micro-Cantilever under Different Deformation Characteristics

2013 ◽  
Vol 477-478 ◽  
pp. 21-24
Author(s):  
Hui Kai Gao ◽  
Jian Meng Huang
Keyword(s):  
Plastic Strain ◽  
Rough Surface ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Adhesive Contact ◽  
Contact Model ◽  
Deformation Characteristics ◽  
Element Analysis ◽  
Flat Substrate ◽  
Micro Cantilever

The contact between substrate and micro-cantilever simplified as an ideal flat substrate contact with a micro-cantilever rough surface. A three-dimensional adhesive contact model was established on isotropic rough surfaces exhibiting fractal behavior, and the equivalent plastic strain was discussed using the finite element analysis. The maximum equivalent plastic strain and its depth were presented with the different paths of rough solid when loading. The result show that the equivalent plastic strain versus different depth which at different locations showed different laws, in the top area of the asperities versus different depth, the maximum equivalent plastic strain occurs in the subsurface range about 0.5μm from the surface or on the surface. In addition, with different deformation characteristics, the degree of the equivalent plastic strain was different.. The contact model between micro-cantilever rough surface and flat substrate will lay a foundation to further research on the substance of the process of friction and wear.

scholarly journals Analysis of the tool plunge in friction stir welding - comparison of aluminium alloys 2024 T3 and 2024 T351

2016 ◽  
Vol 20 (1) ◽  
pp. 247-254
Author(s):  
Darko Veljic ◽  
Bojan Medjo ◽  
Marko Rakin ◽  
Zoran Radosavljevic ◽  
Nikola Bajic
Keyword(s):  
Friction Stir Welding ◽  
Plastic Strain ◽  
Heat Generation ◽  
Aluminium Alloys ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Fe Model ◽  
Arbitrary Lagrangian Eulerian ◽  
Friction Stir ◽  
Tool Pin

Temperature, plastic strain and heat generation during the plunge stage of the friction stir welding (FSW) of high-strength aluminium alloys 2024 T3 and 2024 T351 are considered in this work. The plunging of the tool into the material is done at different rotating speeds. A three-dimensional finite element (FE) model for thermomechanical simulation is developed. It is based on arbitrary Lagrangian-Eulerian formulation, and Johnson-Cook material law is used for modelling of material behaviour. From comparison of the numerical results for alloys 2024 T3 and 2024 T351, it can be seen that the former has more intensive heat generation from the plastic deformation, due to its higher strength. Friction heat generation is only slightly different for the two alloys. Therefore, temperatures in the working plate are higher in the alloy 2024 T3 for the same parameters of the plunge stage. Equivalent plastic strain is higher for 2024 T351 alloy, and the highest values are determined under the tool shoulder and around the tool pin. For the alloy 2024 T3, equivalent plastic strain is the highest in the influence zone of the tool pin.

scholarly journals USING MOBILE LASER SCANNING DATA FOR FEATURES EXTRACTION OF HIGH ACCURACY DRIVING MAPS

2016 ◽  
Vol XLI-B3 ◽  
pp. 433-439 ◽  
Author(s):  
Bisheng Yang ◽  
Yuan Liu ◽  
Fuxun Liang ◽  
Zhen Dong
Keyword(s):  
Laser Scanning ◽  
Human Error ◽  
Traffic Accidents ◽  
Three Dimensional ◽  
Point Clouds ◽  
High Accuracy ◽  
3D Point Clouds ◽  
Assistant Systems ◽  
Novel Method ◽  
High Flexibility

High Accuracy Driving Maps (HADMs) are the core component of Intelligent Drive Assistant Systems (IDAS), which can effectively reduce the traffic accidents due to human error and provide more comfortable driving experiences. Vehicle-based mobile laser scanning (MLS) systems provide an efficient solution to rapidly capture three-dimensional (3D) point clouds of road environments with high flexibility and precision. This paper proposes a novel method to extract road features (e.g., road surfaces, road boundaries, road markings, buildings, guardrails, street lamps, traffic signs, roadside-trees, power lines, vehicles and so on) for HADMs in highway environment. Quantitative evaluations show that the proposed algorithm attains an average precision and recall in terms of 90.6% and 91.2% in extracting road features. Results demonstrate the efficiencies and feasibilities of the proposed method for extraction of road features for HADMs.

scholarly journals VISUALIZATION OF THE CONSTRUCTION OF ANCIENT ROMAN BUILDINGS IN OSTIA USING POINT CLOUD DATA

2017 ◽  
Vol XLII-2/W3 ◽  
pp. 345-352
Author(s):  
Y. Hori ◽  
T. Ogawa
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Feature Matching ◽  
Three Dimensional ◽  
Point Clouds ◽  
Final Report ◽  
Point Cloud Data ◽  
Cloud Data ◽  
Coverage Accuracy ◽  
New Research

The implementation of laser scanning in the field of archaeology provides us with an entirely new dimension in research and surveying. It allows us to digitally recreate individual objects, or entire cities, using millions of three-dimensional points grouped together in what is referred to as "point clouds". In addition, the visualization of the point cloud data, which can be used in the final report by archaeologists and architects, should usually be produced as a JPG or TIFF file. Not only the visualization of point cloud data, but also re-examination of older data and new survey of the construction of Roman building applying remote-sensing technology for precise and detailed measurements afford new information that may lead to revising drawings of ancient buildings which had been adduced as evidence without any consideration of a degree of accuracy, and finally can provide new research of ancient buildings. We used laser scanners at fields because of its speed, comprehensive coverage, accuracy and flexibility of data manipulation. Therefore, we “skipped” many of post-processing and focused on the images created from the meta-data simply aligned using a tool which extended automatic feature-matching algorithm and a popular renderer that can provide graphic results.

scholarly journals Weighing trees with lasers: advances, challenges and opportunities

2018 ◽  
Vol 8 (2) ◽  
pp. 20170048 ◽  
Author(s):  
M. I. Disney ◽  
M. Boni Vicari ◽  
A. Burt ◽  
K. Calders ◽  
S. L. Lewis ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Three Dimensional ◽  
Point Clouds ◽  
3D Models ◽  
Tree Form ◽  
Form And Function ◽  
Challenges And Opportunities ◽  
And Function ◽  
Non Destructive

Terrestrial laser scanning (TLS) is providing exciting new ways to quantify tree and forest structure, particularly above-ground biomass (AGB). We show how TLS can address some of the key uncertainties and limitations of current approaches to estimating AGB based on empirical allometric scaling equations (ASEs) that underpin all large-scale estimates of AGB. TLS provides extremely detailed non-destructive measurements of tree form independent of tree size and shape. We show examples of three-dimensional (3D) TLS measurements from various tropical and temperate forests and describe how the resulting TLS point clouds can be used to produce quantitative 3D models of branch and trunk size, shape and distribution. These models can drastically improve estimates of AGB, provide new, improved large-scale ASEs, and deliver insights into a range of fundamental tree properties related to structure. Large quantities of detailed measurements of individual 3D tree structure also have the potential to open new and exciting avenues of research in areas where difficulties of measurement have until now prevented statistical approaches to detecting and understanding underlying patterns of scaling, form and function. We discuss these opportunities and some of the challenges that remain to be overcome to enable wider adoption of TLS methods.

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