Papers by Keyword: Ground Penetrating Radar (GPR)

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Authors: Yun Gyeong Choi, Jung Hee Suh, Nu Ree Han, Ji Hyang Choi, Young Ho Cha
Abstract: We have chosen the GPR method for investigating the inner structure of a stone pagoda in a non-destructive way. The selection of a suitable source frequency of the GPR antenna is the key because the main frequency of its pulse controls the resolution and the depth of the investigation. Through theoretical consideration and numerical simulation, we found that 500 to 800 MHz is suitable for a field model with a foundation part of 3 to 4 m. To image the inner structure we selected 3-D Kirchhoff prestack depth migration technique used in seismic processing. We have used the modified migration algorithm for the source and receiver configurations of common offset GPR data. To verify the scheme, we calculated the synthetic data using the 3-D FDTD algorithm and applied the migration technique to it. Through these experiments, we confirmed that the 3-D Kirchhoff prestack depth migration technique is a very powerful tool to image the inside of a stone pagoda with high resolution. We have also applied the technique to the field data of the foundation of a five-story stone pagoda at Jeongnim temple site in Buyeo City, Korea. Based on the 3-D migrated images, we inferred that the structure of the foundation of this pagoda seemed to be preserved quite well and the thickness of the outer wall was about 0.5 m.
Authors: Jie Liu, Yuan Shui Cheng
Abstract: Stable structure of subgrade of railway is an important foundation for safety of train. Rising of speed and heavy transport tasks accelerate deterioration of ballast and increase disease of subgrade. It is more important how to detect and maintain the condition of ballast and subgrade highly effective, faster and without any destruct. In recent years, the ground penetrating radar has been an effective method for detecting and evaluation ballast and subgrade. This paper present application of detecting and evaluation ballast and subgrade by using the train-mounted-multicenter ground penetrating radar(GPR), data processing and interpretation, acknowledge and some problem.
Authors: Wen Tai Lei, Yu Jia Shi
Abstract: The article proposes a new imaging method for ground penetrating radar (GPR) nondestructive testing (DET). Traditional GPR range migration (RM) imaging algorithm regards all the data in GPR echo data as equally important. This assumption is always not in consistent with real GPR detection scenario and usually cannot obtain high quality imaging results. To improve the quality of GPR imaging results, a new windowed RM imaging algorithm is presented in this paper. The radar profile is processed by one-dimensional windowed Fourier transform. The central point of window function is determined by maximum intensity technique. By using windowed RM imaging algorithm, the clutter of GPR profile is suppressed and the imaging results quality is improved. The simulation of this algorithm is processed and experimental results validate the feasibility of this algorithm.
Authors: Sun Yong
Abstract: In the process of engineering prospective design and constructing, it is necessary to avoid the adverse impact of geological phenomena, such as fault, karst and landslide. Therefore, it’s important to choose a favorable project address by scientific and effective detection with engineering geological conditions. The main exploration method for geological conditions is the geophysical exploration, including: high density electrical method, ground penetrating Radar, seismic exploration method and so on. The discrimination result with a single geological method changes much, and it is difficult to make an accurate analysis of the geological conditions. So we should composite a variety of exploration methods. In this paper, it expounds the fundamental, the working method, data explanations of the high density electrical method and ground penetrating Radar firstly. And then it takes exploration of candidate sites of an aluminum waste disposal plant for example, the geological conditions of candidate sites are analyzed under the two geophysical methods. The study results of engineering site option have a positive role in guiding the work.
Authors: Fang Wang, Shao Hui He, Jun Liu, Fa Lin Qi
Abstract: The Golmud-Lhasa section of Qinghai-Tibet railway is located in the plateau and permafrost region which tunnel lining produces serious diseases in the extremely bad environment. This paper states the application of Ground Penetrating Radar (GPR) for quality detection of tunnel lining and how to choose parameters, sit detection lines, analyze GPR cross section and classify lining diseases in filed investigation. The results suggest that non-destructive testing technology of GPR can be used to detect the tunnel lining diseases mainly including second lining thickness, cavities and backfilling imperfection zones, and the technology is effectively to detect tunnel lining in abominable surroundings. Furthermore, detection results can provide scientific basis to evaluate the tunnel’s safety performance and diseases degree objectively
Authors: Qiu Nan Chen, Xiao Cheng Huang, Jian Xin Li
Abstract: Based on electromagnetic propagation theory, and used reflected wave detection method of Ground Penetrating Radar. To detect the tunnel with empty areas, void areas, non-dense areas, voids and other defects by the GPR. According to Jianshan Tunnel on-site detection, combined with practical examples to illustrate the GPR as a mean of nondestructive testing. The existence of tunnel defects and their reasons are analyzed comprehensively, and a series of processing measures are proposed.
Authors: Le Wen Zhang, Huai Feng Sun, Shu Cai Li, Dao Hong Qiu, De Yong Zhang
Abstract: The authors found a type of sidewall failure during the construction of a tunnel with high geostress. And relative strong rockburst usually occurred in the areas nearby during the excavation. This paper shows this type of failure called Crisp Fissure Failure and some characteristics of the failure. Reasons of the failure are also discussed. Further more, the authors studied the fracture distribution under this type of failure by Ground Penetrating Radar. Suggestions of support in a high risk tunnel are put forward based on the research of the Crisp Fissure Failure.
Authors: Shao Kun Ma, Xiao Yao, Yan Zhen Huang, Xiao Bing Zhou
Abstract: This paper briefly introduces the principle and method of GPR, as well as the related manual during the application process. Then a case in karstic region is presented. This paper is aimed at giving some guidance to the application of GPR on geophysical prospecting for the building foundation in karstic region.
Authors: Jing Zhang, Bing Han, Peng Liu
Abstract: This paper presents researches on the technique for testing water content and moisture field in concrete by GPR. Through the experiments, a discussion has been carried out on the variation of velocity of radar waves and the relative dielectric constants in the concrete with different water content. Comparing the results of air drying and drying experiment, an equation is given to reflect the relation between the water content in the concrete and the radar speed of radar waves in the concrete, also the relative dielectric constants of concrete. Some suggestions are proposed for the actual concrete water content test by using Ground Penetrating Radar (GPR).
Authors: Hong Yuan Fang, Jian Li, Jia Li
Abstract: The second-order Lobatto IIIA-IIIB symplectic partitioned RungeKutta (SPRK) method, combining with the first-order Mur absorbing boundary condition, is developed for the simulation of ground penetrating radar wave propagation in layered pavement structure. For 2-dimetional case, a significant advantage of this method is that only two functions need to be calculated at each time step. The total-field/scattered-field technique is used for plane wave excitation. Numerical examples are presented to verify the accuracy and efficiency of the proposed algorithm. The results illustrate that the reflected signal calculated by the SPRK method is in good agreement with that obtained using the finite difference time domain (FDTD) scheme, but the CPU time consumed by proposed algorithm is reduce about 20% of the FDTD scheme. In addition, an actual field test is conducted to evaluate the further performance of the SPRK method. It is found that the simulated waveform fits well with the measured signal in many aspects, especially in the peak amplitude and time delay.
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