Einfluß von Verwitterungsgrad und Trennflächengefüge auf den maschinentechnischen Lösevorgang an überkonsolidierten Tonund Mergelsteinen

Summary

The structural strength of claystones and marlstones during excavation with hydraulic excavators depends on several factors, which include the degree of weathering (fig. 12a) as expressed by point-load index (fig. 12d), the average joints spacing throughout the rock body (figs. 12c and 18), and the orientation of the joint sets (figs. 9a and b). Due to the complexity of the fracturing (and consequent shearing) processes which occur during excavation of the rock, a number of investigations was conducted in the field rather than in the laboratory. In order to determine the forces applied during excavation, the oil pressure (figs. 4 and 8) and length of the piston-stroke (figs. 4 and 7) of the hydraulic cylinders of the excavator were measured. These values were then interpreted in terms of the three above mentioned geotechnical parameters and statistically analysed (figs. 13 to 16). This provided the basis for a Classification scheme for the economic feasibility of excavation as related to the degree of weathering and the spacing of vertical joint sets (fig. 18).