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18 results on '"Dong, Chaowei"'

5. High Accuracy Reconstruction of Airborne Streak Tube Imaging LiDAR Using Particle Swarm Optimization.

Author

Wang, Xing, Chen, Zhaodong, Dong, Chaowei, Dong, Zhiwei, Chen, Deying, and Fan, Rongwei

Subjects
PARTICLE swarm optimization, REMOTE sensing, POINT cloud, LIDAR, TUBES
Abstract

Airborne streak tube imaging LiDAR (STIL) consists of several different data-generating subsystems and introduces system errors each time it is installed on an aircraft. These errors change with each installation, which makes the parametric calibration of the LiDAR meaningless. In this study, we propose a high-precision reconstruction method for point clouds that can be used without calibrating the system parameters. In essence, after each remote sensing measurement, a self-checking process is performed with experimental data to replace the fixed system parameters. In this process, the splicing error of the same region measured under different conditions is used as a criterion to optimize the reconstruction parameters via a particle swarm optimization (PSO) algorithm. For a detection distance of 3000 m, the elevation error of the point cloud reconstruction reaches more than 1 m if the placement parameters are not optimized; after optimization, the elevation error can be controlled within 0.3 m. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Research on support of composite bearing body in longwall-roadway cemented backfilling

Author

YAO Yinan, DONG Chaowei, LAI Wan’an, GUO Yaben, and ZHONG Lei

Subjects
longwall-roadway cemented backfilling, combined bearing capacity of coal body and backfill, numerical simulation, stress evolution, supporting design, Mining engineering. Metallurgy, TN1-997
Abstract

The supporting efficiency of the filling roadway during longwall-roadway cemented backfilling process greatly affects the speed of roadway driving. In order to simplify the support during the mining process when both sides of the filling roadway are in the dynamic combination of coal body-coal body, filler-coal body, and filler-filler surrounding rock, this paper uses numerical simulation to obtain the stress evolution law of the coal and the backfill in a single mining cycle. According to the different composite bearing characteristics of the coal and the filling body around the filling roadway, three supporting schemes are designed and the supporting effect is analyzed. It is found that at different stages of a single mining cycle, the coal body is the main bearing part of the composite load-bearing system, with the maximum vertical stress of 34.4 MPa and the stress concentration coefficient of 2.33. The vertical stress range of the filler is about 0.5 MPa to 2.13 MPa, and the change range is small. In the process of tunneling, when the support on the side of the filling body is reduced, the section shrinkage rate of the filling roadway in the three states is 2.84%, 4.38% and 13.33%, respectively. In other words, the reduced support has little influence on the roadway deformation when the coal-filling body compound bearing capacity exists in a single mining cycle.

Published
2021
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14. Experimental study of the creep properties of coal considering initial damage

Author

Huang Peng, Chai Jun, Dong Chaowei, Spearing A.J.S., Zhang Jixiong, Huang Peng, Chai Jun, Dong Chaowei, Spearing A.J.S., and Zhang Jixiong

Abstract

Damage around rock or coal faces usually occurs from the time mining starts. This initial damage is rarely considered during creep tests used for coal. An experimental specimen processing method to identify the initial damage to a coal deposit is suggested which takes into account the effect of the strain history on the deformation of coal samples during multi-level loading triaxial compression creep tests. Results showed that the strain versus creep curve of the coal samples experiences three typical creep stages: deceleration creep in the early stage, constant velocity creep in the medium term and catastrophic accelerated creep in the later stage. With the increase in initial damage, a gradual decrease in total creep time was observed along with decreases in deviating stress of creep failure, stress threshold of accelerated creep and starting time of the volume expansion. It is concluded that it is important to conduct research on the deformation, mechanical characteristics and long-term strength of a coal pillar with initial damage under long-term pressure, which will also provide insight into underground excavation and the design of supports., Damage around rock or coal faces usually occurs from the time mining starts. This initial damage is rarely considered during creep tests used for coal. An experimental specimen processing method to identify the initial damage to a coal deposit is suggested which takes into account the effect of the strain history on the deformation of coal samples during multi-level loading triaxial compression creep tests. Results showed that the strain versus creep curve of the coal samples experiences three typical creep stages: deceleration creep in the early stage, constant velocity creep in the medium term and catastrophic accelerated creep in the later stage. With the increase in initial damage, a gradual decrease in total creep time was observed along with decreases in deviating stress of creep failure, stress threshold of accelerated creep and starting time of the volume expansion. It is concluded that it is important to conduct research on the deformation, mechanical characteristics and long-term strength of a coal pillar with initial damage under long-term pressure, which will also provide insight into underground excavation and the design of supports.

Published
2021

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