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- Title
Kayaç kazılabilirliğinin tayini için taşınabilir kayaç kesme deney aletinin geliştirilmesi.
- Authors
Ferıdunoğlu, Osman Cenk; Bılgın, Nuh
- Abstract
Full face tunnel boring machines and partial face tunnel boring machines utilization for mining and civil project are increasing enormously. Tunnels for civil projects at highly populated cities dictate minimum ground disturbance while tunneling. Full face tunneling machines are able to excavate through hard rock to soft ground with small surface deformation and faster compared to drill and blast. Selection of correct mechanized excavator for a given rock media is very important for the success of the project. A great care must be taken for equipment selection and performance prediction in the project design phase. Researchers worked on a wide range of parameters to predict the performance of mechanical excavators. Besides the theoretical approaches, the ones who correlate the mechanical properties of intact rock to the field performance of the excavators are more reliable in their data range and tunneling conditions. Full scale linear rock cutting, small scalecore cutting and University of Trondheim performance prediction model are widely accepted on the international tunneling society. Laboratory cutting tests are expensive, needs specialists, special equipments and may take long time to perform. Therefore, a portable, easy to use, reliable, costsless than 10000 $ small scale rock cutting rig is developed in the scope of this research. The table ofthe rig is moved by a hydraulic cylinder powered by a hydraulic accumulator. Rock samples in 20×20×10 cm of size attached to the table with a special mechanism to cut the rock with a mini-disc, diameter of 13 cm and tip angle of 70°, and the forces acting on the mini-disc and specific energy to cut a unit volume of rock is measured. A force dynamometer equipped with strain gauges are developed in the scope of Tübitak Project No: MİSAG-274, to measure the forces and a data acquisition system that can collect 1000 data in a second is chosen. Many calibrations are performed to test the reliabilityof the dynamometer and data acquisition system. Calibrations are done by a hydraulic cylinder whosecross section area is known. Hydraulic cylinder is pressurized to 10, 20, 30, 40, 50 bar with a 9º inclined surface to the mini disc. Output from the dynamometer strain gauges are compared to the applied force where it is seen that output is linearand has R2 equals to 0.99. It is proved that the resultsof the developed cutting rig are reliable and repeatable. While making a cutting on the developed cutting rig, there are two ways to fix the rock sample. One can use the manufactured case where rock sample can be cemented inside. The other is to use the screwed clamp on the moving table. It is hard to adjust the cutting depth while pouring the cement into the case.Another disadvantage is you can only use one face of the rock sample. In this study, screwed clamp is used to make the cutting test because it is easy, faster to fix the sample and gives the opportunity tomake 4 cuttings per sample.. Rock cutting tests are carried out on 14 different rock samples with the full scale linear cutting rig and the developed portable rock cutting rig. A 13" constant cross section (CCS) disc cutter and minidisc is used for the cutting tests with full scale linear cutting rig. Results from the full scale cutting rig 13" CCS with mini disc equipped developed rig are compared for 8 different rock samples for an unrelieved 5 mm depth of cut. …
- Subjects
ROCKS; TUNNEL construction equipment; DYNAMOMETER; GAGES; HYDRAULIC accumulators; HYDRAULIC cylinders; ERGOMETRY; EXCAVATION; EARTHWORK
- Publication
ITU Journal Series D: Engineering, 2010, Vol 9, Issue 3, p66
- ISSN
1303-703X
- Publication type
Article