scholarly journals Dam Leakage Detection by Borehole Radar: A Case-History Study

2019 ◽  
Vol 11 (8) ◽  
pp. 969 ◽  
Author(s):  
Sixin Liu ◽  
Xudong Wang ◽  
Qi Lu ◽  
Honqing Li ◽  
Yuanxin Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Internal Erosion ◽  
Leakage Detection ◽  
Low Velocity ◽  
Dam Foundation ◽  
Concrete Walls ◽  
Single Hole ◽  
Reflection Profile ◽  
Borehole Radar ◽  
Water Saturated

A borehole radar investigation was performed at the Sanzuodian reservoir, Chifeng, China to assess possible leakage paths located in the deep dam foundation. The key methodologies used include both single-hole reflection and cross-hole radar tomography, which make a high-resolution identification of the hydraulic connection paths between upstream and downstream sides possible. The leakage paths are characterized by direct wave loss due to high electromagnetic attenuation in the single-hole reflection profile and the nearly horizontal-banded low-velocity zone in the cross-hole velocity tomography due to possible large internal erosion. Meanwhile, some small structures inside the dam, including the core wall thickness changing point, the connecting point between asphalt and concrete walls, and the contacting interface between the dry and the water-saturated formations can be identified from the single-hole reflection profile clearly. Interpreted leakage paths are proven by the water flow measurement. Borehole radar is a useful high-resolution tool, suitable for deep leakage detection and evaluation.

$\hbox{HE}_{11}$ Mode Effect on Direct Wave in Single-Hole Borehole Radar

2011 ◽  
Vol 49 (2) ◽  
pp. 854-867 ◽  
Author(s):  
Satoshi Ebihara ◽  
Akihito Sasakura ◽  
Taro Takemoto
Keyword(s):  
Direct Wave ◽  
Single Hole ◽  
Mode Effect ◽  
Borehole Radar

scholarly journals Permittivity Measurement Using Borehole Radar from Single Hole

2004 ◽  
Author(s):  
S. Lin ◽  
Y. Sanada ◽  
T. Matsuoka ◽  
Y. Ashida
Keyword(s):  
Permittivity Measurement ◽  
Single Hole ◽  
Borehole Radar

A High-Resolution, Short-Range, Directional Borehole Radar

2001 ◽  
Author(s):  
David L. Wright ◽  
Jared D. Abraham ◽  
David VonG. Smith ◽  
S. Raymond Hutton
Keyword(s):  
High Resolution ◽  
Short Range ◽  
Borehole Radar

scholarly journals Negative Pressure Waves Based High Resolution Leakage Localization Method Using Piezoceramic Transducers and Multiple Temporal Convolutions

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 1990 ◽  
Author(s):  
Guangmin Zhang ◽  
Siu Chun Michael Ho ◽  
Linsheng Huo ◽  
Junxiao Zhu
Keyword(s):  
High Resolution ◽  
Lead Zirconate Titanate ◽  
Negative Pressure ◽  
Lead Zirconate ◽  
Signal Duration ◽  
Leakage Detection ◽  
Localization Algorithm ◽  
Large Area ◽  
Leakage Area ◽  
Better Than

The negative pressure wave (NPW) signals generated by a pipeline leakage often have a long signal duration. When these signals are utilized to compute the leakage position, the long signal duration will result in a large area being considered as leakage area. The localization resolution is low. A novel high-resolution localization algorithm is developed for pipeline leakage detection using piezoceramic transducers in this paper. The proposed algorithm utilizes multiple temporal convolutions to decrease the localization functional values at the points close to the leakage, in order to reduce the range of the leakage area revealed by the proposed algorithm. As a result, the localization resolution is improved. A measured experiment was conducted to study the proposed algorithm. In the experiment, the proposed algorithm was used to monitor a 55.8 m pressurized pipeline with two controllable valves and two Lead Zirconate Titanate (PZT) sensors. With the aid of the piezoceramic sensor, the experimental results show that the proposed algorithm results in a resolution which is better than that of the traditional method.

scholarly journals Fragmentary structure in the L1551 molecular outflow

1991 ◽  
Vol 147 ◽  
pp. 480-481
Author(s):  
Nicholas D. Parker ◽  
Glenn J. White
Keyword(s):  
High Resolution ◽  
Thin Shell ◽  
Low Velocity ◽  
Fragmentary Structure ◽  
Molecular Outflow ◽  
High Resolution Map ◽  
Ambient Gas ◽  
Resolution Map

We have obtained a high resolution map of the 12CO J=3—2 emission in the vicinity of HH102 in the L1551 molecular outflow. The data reveal the presence of several bright clumps within the thin shell of low-velocity blue-shifted outflowing gas. There is evidence for further fragmentation in the clumps, as signified by the high derived excitation temperatures and low beam-filling factors. The region of peculiarly energetic activity associated with HH102 coincides with the projected location of impact of a radio jet from IRS5 with the dense ambient gas surrounding the outflow cavity.

scholarly journals Geophysical Evaluation of the Inner Structure of a Historical Earth-Filled Dam

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 664 ◽  
Author(s):  
David Zumr ◽  
Václav David ◽  
Josef Krása ◽  
Jiří Nedvěd
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Seepage Flow ◽  
The Body ◽  
Internal Erosion ◽  
Dam Foundation ◽  
High Resolution Data ◽  
15Th Century ◽  
Ground Penetrating ◽  
Non Destructive

Small earth dams usually lack the detailed seepage monitoring system that would provide high resolution data on changes in seepage flow. Alternative solution is monitoring of the temperature and electrical resistivity in the body of the dams. Geophysical methods are useful techniques for a non-destructive exploration of the subsurface. We have utilized the combination of electrical resistivity tomography (ERT), ground penetrating radar (GPR) and multi-depth electromagnetical conductivity meter (CMD) techniques to observe the inner structure, especially internal failures, of the historical earth-filled dams. Longitudinal and transversal profiles of four typical fishpond dams in the Czech Republic were measured within this research. The dams were constructed as early as in the 15th century, some of them went through minor reconstruction. The aim of the application of geophysical methods for investigation of old fishpond dams was to detect and localize the boundary of the dam foundation, new earth material from the reconstruction works, cone of water depression, technical objects location, potential internal erosion, cavities, inhomogeneity in the water content pattern and any other anomalies. The primary results show that the ERT is suitable to observe the dam stratification, dam foundation, bedrock below the dam and large anomalies. GPR is suitable for small objects and anomalies detection in the shallow depths.

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