Arbetsresultat efter markberedning med en tvåhövdad hängande testbänk med inversfunktion

Abstract: Today, inverting is performed mostly using crane-mounted devices. These devices must increase their productivity in order to become more cost-competitive. One way to increase productivity is to make a two-headed device that can prepare the soil using both inverting and mounding. The purpose of this study was to evaluate a two-headed test bench with an inverting and mounding function. The study aimed to characterize the planting spots, judge the site preparation result, and measure the hydraulic pressure required to produce acceptable planting spots on soils with varying frequencies of obstacles. The study was conducted in Alvesta, Småland at the site of a future industrial area. The soil was a typical rocky Swedish moraine/till. The study comprised 29 crane stops on humus-covered forest soil. Each crane stop had been pre-marked and characterized using the Swedish Terrain Classification System. A number of crane stops were also evaluated on soil lacking humus layers. All crane stops were filmed to assist the data analysis. Instead of inverting, the test bench only succeeded in mounding. On average, shallowly dug spots disturbed an area of 82dm2, and deeply dug spots disturbed 87dm2. The mounds measured, on average, 20dm2 at both the deeply and shallowly dug spots. Thus, the device’s theoretical total site disturbance when mounding was 16% (assuming 2000 mounds/hectare). If properly performed, inverting would have the theoretical potential to reduce the device’s total site disturbance to 12%. The percentage of satisfactory planting spots was 55%, which was acceptable given that the test bench had an incomplete working method. The results also pointed towards a link between higher obstacle frequencies and lower proportions of acceptable planting spots. At the start of the study, it was noted that the device constantly worked at maximum pressure when the buckets were digging in obstacle-free ground. This indicated that the test bench’s hydraulic system was too weak. Digging shallowly partially compensated for this hydraulic weakness. Shallow digging also resulted in the device being less affected by obstacles in the ground. To get an indication of the test bench’s efficiency, I also measured the device’s time consumption when mounding at different soil obstacle frequencies. My hypothesis was that more obstacles would result in higher time consumption. The results supported the hypothesis, but the support was very weak. One of the conclusions of the study is that the goal of soil preparation should be to make as shallow soil preparation spots as possible, as this results in a lower power requirement, that the device is less affected by obstacles, and less soil disturbance.