Relaxation in Safety Thanks to Correction DataSoil Compaction in Lusatia/Germany

By 2018, Europe’s largest artificial water landscape will be developed on the territory of the former brown coal mines. Before entering this region, however, it will have to be secured against ground failures and flow reduction. Here, the vibro flotation densification is applied.

This picture displays the grasp method of a cable dredger. The boom is equipped with many different sensors, among others, with receivers for AXIO-NET correction data.

Brown coal mines characterised Lusatia for a long time. Spoil heaps and abandoned opencast mines are visible indications of days gone by. However, this is planned to change by the means of a spectacular construction project: The open pit mines will be flooded and structurally linked to each other so that the Lusatian Lakeland will develop to the largest artificial water landscape in Europe by 2018. In this context, the correction data provided by AXIO-Net play a decisive role.

The re-cultivation of former overburden and opencast mining sites requires a great deal of time and effort, as the flooding of the surfaces results again in the increase of the groundwater table. The soils, which mainly consist of sands, easily start to slide. Before this region can be opened to tourism, the slopes of the future lake district will have to be compressed. A delicate challenge the experts Spezial- und Bergbau-Servicegesellschaft Lauchhammer mbH (SGL) have met. With special equipment the current construction phases „Überleiter 11“ and „Schwarze Keute“ are compressed according to the vibro-replacement technique. Applying this method means that safety comes first; for there is danger to life when areas being endan-gered by slope fractures are entered. That is why, among others, a dredger with a 63-metre long boom and a 35-metre long vibrator lance are used.

In order to control them exactly at one of the 10,000 vibro locations in total, the supplier Tolk & Düsterhus Baggersysteme GmbH installed a satellite-based machine control system on the device. The large number of compacts within a small area requires a high degree of precision to keep exactly the distance between the individual points. To position the lance automatically, the precise real-time service PED provided by AXIO-NET is used. This service offers an accuracy of two centimetres. So this makes a setup of an own reference station superfluous and pays off especially under these difficult conditions. To apply the classical surveying methods under the existing difficult circumstances would be a life-threatening task. Beyond that, using correction data simplifies on the one hand the processes of planning and the implementation of activities and supplies on the other hand the ideal data basis for observing the documentation obligation.

The technical basis of the system is provided by two Javad receivers which have been installed on the mast top in order to determine the position and direction. To receive AXIO-NET correction data a come2ascos modem from Allsat is used. The data transfer from AXIO-NET s̀ computing centre to the modem is made in real time via mobile phone connection. In the meantime, the Prolec control system PCX 3D, that is mapping all machine movements in a digital terrain model, provides the processing and visualisation of the data. In this combination, the system makes possible a positional accuracy of a few centimetres and therefore constitutes a prerequisite for future measurements – without neglecting the security aspect.

Further Information:AXIO-NET GmbHAm Hohen Ufer 3A30159 HannoverPhone: +49 (0)511 123718-90Fax: +49 (0)511 123718-99E-Mail: info@axio-net.euWeb: www.axio-net.eu

Enabling the precise positioning of the lance on top of the vibro location, the precise real-time service (PED) of AXIO-NET is used.