The main application of the mobile geo-electrical measurement is the detection of the presence and determining the location of leakage in sewer systems. To do so, this method relies on the increase in the measured electrical current between an electrode inside and an electrode outside the sewer system. To use this technique for the quantification of leakages further assumptions on the measured current are required. In this study, a model to simulate the geo-electrical measurement system is developed. Laboratory experiments are conducted to investigate the influence and contribution of the model components on the measured current and the validity of the assumptions. The experimental results demonstrate that multiple components significantly contribute to the measured current apart from the leakage in the pipe. As a consequence, the properties of the leakage in the pipe are likely to be significantly under- or overestimated in most measuring systems currently applied in practice.

Distributed temperature sensing (DTS) can be used to monitor the production process of diaphragm walls. DTS is able to differentiate between already present or fresh bentonite suspensions during refreshing of the bentonite slurry in the trench. During concrete casting, DTS is able to differentiate between the bentonite suspension and concrete. As a result, the continuity of the casting process and the arrival of good grade concrete at crucial locations in the trench can be monitored. Tests conducted on laboratory models provided reference information for interpretation of field data. Field experiences have shown the benefits of DTS tests and the predictive value of the reference measurements. Results are compared with crosshole sonic logging measurements at the same location.