期刊：
Journal of Applied Geophysics,2021年186:104273 ISSN：0926-9851
通讯作者：
Zhang, Liang(zhangliang@hncu.edu.cn)
作者机构：
[Zhang, Liang; Zhang, Sheng] Hunan City Univ, Hunan Engn Res Ctr Struct Safety & Disaster Preve, Yiyang 413000, Hunan, Peoples R China.;[Zhang, Liang; Zhang, Sheng] Hunan City Univ, Coll Civil Engn, Yiyang 413000, Hunan, Peoples R China.;[Ling, Tonghua; Yu, Bin; Huang, Fu] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Liang Zhang] H;Hunan Engineering Research Center of Structural Safety and Disaster Prevention for Urban Underground Infrastructure, Hunan City University, Yiyang, Hunan 413000, China<&wdkj&>College of Civil Engineering, Hunan City University, Yiyang, Hunan 413000, China
摘要：
To reduce the shielding effect of strong jamming signals such as direct waves and multiple echoes on the effective signals in ground penetrating radar (GPR) images and effectively improve the GPR image resolution, a method to remove strong interference signals in GPR that combines the wavelet transform and F-K filtering is proposed. First, we choose a biorthogonal wavelet basis that matches the waveform of GPR signal, and an original GPR image is decomposed into subimages of different frequency bands based on the optimal wavelet basis. Second, according to the difference in the distribution of the effective signals and the strong interference of different subsignal images in the wavenumber domain, different bandpass filters are designed to accurately separate the effective signals and strong interference, and the subimages are reconstructed after the interference being removed. The processing of the forward simulated and measured GPR images shows that the combined method of wavelet transform and F-K filtering can produce different F-K filters according to the characteristics of different subsignal images and accurately process the image, suppressing the strong interference and retaining the effective signals to the greatest extent. Compared to the results of the predictive deconvolution method and the conventional F-K method, the cavity reflection in the image processed by the proposed method is more obvious, the coaxial signal is continuous and clear, and the image resolution is improved, which proves the feasibility and effectiveness of this method in separating strong interference waves. (C) 2021 Elsevier B.V. All rights reserved.
通讯机构：
[Zhang, Sheng] H;[Zhang, Sheng] U;Hunan City Univ, Sch Civil Engn, Yiyang 413000, Peoples R China.;Univ Houston, Dept Mech Engn, Houston, TX 77204 USA.
摘要：
<jats:p>In blasting excavation of neighborhood tunnels, damage accumulation process in surrounding rock is inevitable. To explore the influence of damage accumulation of rock mass under multiple blasting loads, we analyzed the vibration damage accumulation process of ultrasonic wave velocity of rock mass in shared rock of Liuyuetian neighborhood tunnel through ultrasonic test. Moreover, the effects of cyclic blasting loads on damage to the shared rock in the neighborhood tunnel were discussed and reported. The results demonstrate that the damage accumulation to the shared rock in the neighborhood tunnel is generated after multicycle progressive blasting operations. Influenced by cyclic blasting loads during the posterior excavating tunnel, the damage range of shared rock at the anterior excavating tunnel is 1.2 to 1.4 m, and the damage range of shared rock at the posterior excavating tunnel is 2.2 to 2.4 m. The damage range of shared rock in the posterior excavating tunnel is about 1.71 to 1.83 times that in the anterior excavating tunnel. Under blasting load, the stress concentration zone of shared rock is close to the blasting excavating face and is mainly within 2 m along the longitudinal axis of the tunnel. With continuous advancement of the blasting excavating face, the stress concentration zone moves forward continuously, and a striped stress concentration zone, which is approximately 2 m deep, is formed gradually. Thus, a method was proposed to determine the damage range of shared rock in the neighborhood tunnel during blasting excavation, as well as the variation law of damage. The experiences and conclusions presented can be used as references in the design and construction of similar engineering projects in the future.</jats:p>
作者机构：
[张胜; 黎永索; 胡达; 蔡鑫] School of Civil Engineering, Hunan City University, Yiyang;413000, China;Department of Mechanical Engineering, University of Houston, Houston;77204, United States;[何文超] School of Civil Engineering, Changsha University of Science & Technology, Changsha
通讯机构：
School of Civil Engineering, Hunan City University, Yiyang, China
期刊：
Journal of Failure Analysis and Prevention,2019年19(4):1135-1143 ISSN：1547-7029
通讯作者：
Shaohe Zhang<&wdkj&>Xingyu Ding
作者机构：
[Jingjing Wu] School of Civil Engineering, Hunan University of Technology, Zhuzhou, People’s Republic of China;[Shaohe Zhang] Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Central South University, Ministry of Education, Changsha, People’s Republic of China;[Xingyu Ding] College of Civil Engineering, Hunan City University, Yiyang, People’s Republic of China;[Feilong Qu] Zhongye Changtian International Engineering Co., Ltd, Changsha, People’s Republic of China;[Xiaohong Xie] Editorial Department of Journal of Earth Science, China University of Geosciences, Wuhan, People’s Republic of China
通讯机构：
[Shaohe Zhang] K;[Xingyu Ding] C;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Central South University, Ministry of Education, Changsha, People’s Republic of China<&wdkj&>College of Civil Engineering, Hunan City University, Yiyang, People’s Republic of China
关键词：
Frequency domain analysis;Geological surveys;Geophysical prospecting;Ground penetrating radar systems;Image enhancement;Microcracks;Processing;Tracking radar;Wavelet analysis;Attenuation and dispersions;Ground penetrating radar (GPR);High resolution processing;Matching pursuit algorithms;Orthogonal matching pursuit;Sparse representation;Time and frequency domains;Weak signal processing;Time domain analysis;algorithm;detection method;filter;ground penetrating radar;identification method;microcrack;numerical method;signal processing;wavelet analysis
摘要：
To reduce the impact of attenuation and dispersion in ground penetrating radar (GPR) detection and to effectively improve GPR profile recording and to identify a weak detection target, a high-resolution processing method based on orthogonal matching pursuit and wavelet spectrum whitening (the OMWS method) is presented. First, according to the matching pursuit algorithm and the strong reflection-forming mechanism and based on sparse representation theory, a sparse dictionary suitable for the characteristics of a strong reflection signal was selected, and the signal was decomposed, which displayed the weak target signal well. Second, wavelet analysis was used to decompose the processed GPR signal into time-domain subsignals in different frequency bands, and each subsignal was whitened by a whitening filter. Then, the processed subsignals were reconstructed. The final results were compared with the results of conventional spectrum whitening method and showed that the OMWS method can accurately weaken the effect of the strong impedance interface and effectively enhance the local information of microcrack-reflected signals in both the time and frequency domains. The resolution of the processed GPR image is greatly improved, and the reflected signal of the hidden microcrack is easily visible. The method is clearer and more intuitive in the expression of the weak signals of hidden microcrack than the conventional spectrum whitening method, and the compensation for the high-frequency of the signals is more obvious.
期刊：
Journal of Engineering Science and Technology Review,2019年12(4):28-37 ISSN：1791-9320
通讯作者：
Zhang, S.
作者机构：
[Li Y.; Zou Y.] School of Civil Engineering, Hunan City University, Yiyang, 413000, China;Smart Materials and Structures Laboratory, Department of Mechanical Engineering, University of Houston, Houston, TX 77204, United States;[He W.] School of Civil Engineering, Changsha University of Science and Technology, Changsha, 410114, China;[Zhang S.] School of Civil Engineering, Hunan City University, Yiyang, 413000, China<&wdkj&>Smart Materials and Structures Laboratory, Department of Mechanical Engineering, University of Houston, Houston, TX 77204, United States
通讯机构：
School of Civil Engineering, Hunan City University, Yiyang, China
