TY  - JOUR
A1  - Scheuermann, Alexander
A1  - Huebner, Christof
A1  - Schlaeger, Stefan
A1  - Wagner, Norman
A1  - Becker, Rolf
A1  - Bieberstein, Andreas
T1  - Spatial time domain reflectometry and its application for the measurement of water content distributions along flat ribbon cables in a full-scale levee model
JF  - Water Resources Research
N2  - Spatial time domain reflectometry (spatial TDR) is a new measurement method for determining water content profiles along elongated probes (transmission lines). The method is based on the inverse modeling of TDR reflectograms using an optimization algorithm. By means of using flat ribbon cables it is possible to take two independent TDRmeasurements from both ends of the probe, which are used to improve the spatial information content of the optimization results and to consider effects caused by electrical conductivity. The method has been used for monitoring water content distributions on a full-scale levee model made of well-graded clean sand. Flood simulation tests, irrigation tests, and long-term observations were carried out on the model. The results show that spatial TDR is able to determine water content distributions with an accuracy of the spatial resolution of about ±3 cm compared to pore pressure measurements and an average deviation of ±2 vol % compared to measurements made using another independent TDR measurement system.
KW  - Damm
KW  - Infiltration
KW  - Bodenfeuchte
KW  - Transient and time domain; Dams; Infiltration; Soil moisture; calibration; levee model; soil moisture measurement; spatial time domain reflectometry
Y1  - 2009
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170425-31601
ER  - 
TY  - JOUR
A1  - Alalade, Muyiwa
A1  - Reichert, Ina
A1  - Köhn, Daniel
A1  - Wuttke, Frank
A1  - Lahmer, Tom
ED  - Qu, Chunxu
ED  - Gao, Chunxu
ED  - Zhang, Rui
ED  - Jia, Ziguang
ED  - Li, Jiaxiang
T1  - A Cyclic Multi-Stage Implementation of the Full-Waveform Inversion for the Identification of Anomalies in Dams
JF  - Infrastructures
N2  - For the safe and efficient operation of dams, frequent monitoring and maintenance are required. These are usually expensive, time consuming, and cumbersome. To alleviate these issues, we propose applying a wave-based scheme for the location and quantification of damages in dams.
To obtain high-resolution “interpretable” images of the damaged regions, we drew inspiration from non-linear full-multigrid methods for inverse problems and applied a new cyclic multi-stage full-waveform inversion (FWI) scheme. Our approach is less susceptible to the stability issues faced by the standard FWI scheme when dealing with ill-posed problems. In this paper, we first selected an optimal acquisition setup and then applied synthetic data to demonstrate the capability of our approach in identifying a series of anomalies in dams by a mixture of reflection and transmission tomography. The results had sufficient robustness, showing the prospects of application in the field of non-destructive testing of dams.
KW  - Damm
KW  - Defekt
KW  - inverse analysis
KW  - damage identification
KW  - full-waveform inversion
KW  - dams
KW  - wave propagation
KW  - OA-Publikationsfonds2022
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20221201-48396
UR  - https://www.mdpi.com/2412-3811/7/12/161
VL  - 2022
IS  - Volume 7, issue 12, article 161
PB  - MDPI
CY  - Basel
ER  -