"Determination of Filter Grain Size in the Horizontal Wells According to DVGW, Bieske and Busch"
This independent study deals with extraction of groundwater by means of horizontal wells. Those wells are used more and more due to the relatively "new" Preussag method. In the past those horizontal wells could be installed only in coarse material which represented a natural filter to protect the filter pipe from send entering. Nowdays it is possible to put sorted filter material around the drain according to the aquifer type to avoid problems mentioned above. The main goal of this study was to determine the size of filter grains around horizontal well drains in order to avoid suffosion and the entering of sand into the filter pipe. A software will be developed that allows the determination of the filter grain size directly form sieve analysis data provided in a spread sheet.
Several solutions to this problem have been proposed from which three methods were used:
In practice engineers have to determine quickly the grain size and this usually must happen on the construction site. That is why, in this independent study, a tool (program) for solving this problem was made. This will give the engineer the opportunity to find the grain size according to three methods using a portable notebook. The program was developed in the object orientated program language Visual Basic. Visual Basic handle the input data (results of sieve analysis) and by means of a spreadsheet calculator Microsoft Excel calculate the filter grain size. The accuracy of the program is verified on well construction sites in Hoyerswerda and Dresden.
- According to Bieske and Luckner
- According to Busch