30 January 2014, 00:00
Lenggries, Germany – In 2012, extensive dam remediation work was carried out on the Sylvenstein Dam, Bavaria's most important water reservoir. As part of this project, BAUER Spezialtiefbau GmbH from Schrobenhausen in Bavaria constructed a diaphragm wall having a depth of up to 70 meters. Subsequently, a new system for recording and monitoring seepage water was installed.
Using a tunnel boring machine, Wayss & Freytag Ingenieurbau AG drilled a 150-meter-long seepage water tunnel with an outer diameter of three meters. So-called drainage columns with a depth of around 40 meters were installed behind the diaphragm wall at three meter intervals. The collected water can thus be discharged into the seepage water gallery and measured.
Once Bauer-separation technology was used for carrying out the diaphragm wall work, a desanding plant and a downstream desilter unit by MAT Mischanlagentechnik GmbH, a subsidiary of BAUER Maschinen GmbH, were used for tunnel drilling again.
For desanding the soil – comprised of gravel, sand and silt – the desanding plant BE425-60 with two-level screening and a BDS250-30K downstream desilter unit were used. The lower level of the desanding plant, designed as a coarse screen, could filter out most of the solid matter due to its fine mesh width of 1.5 millimetres. Thereafter, the separated solid matter was discharged through the dewatering screen and the downstream desilter unit in a dry state.
Depending on requirement and soil composition, the second desanding stage, namely the BDS250-30K, can be added in bypass. This allows only the necessary separation techniques to be deployed, which reduces energy consumption as well as the wear of those modules which are not required.
Source: BAUER Aktiengesellschaft; Bauer Group