Rock Slope Stability Analysis for the Seven Catracts Vista Road Cut of The Mt. Lemmon Higway, tucson, Arizona

摘要

The seven cataracts Vista road cut is located eight miles up the Mt. Lemmon Highway northeast of Tucson, Arizona. The rock mass in the area has a number of discontinuities that produce a potentially unstable slope, as the present cut slope is approximately 90 deg in most of the area. the purpose of this study was to determine the stability of the road cut. Field data were collected on discontinuity geometry using scanline surveys. Also rock joints and intact rock samles were obtained from the field to perform laboratory tests to determine basic rock joint properties as well as routine intact rock properties. Discontinuity geoemtry data were analyzed to estiamte important discontinuity geometry parameters to perform rock slope kinematic and block theory analyses. The results support in-field obsrvations of a potentially unstable slope. The block theory analysis resulted in he identification of eight key blocks, of which the lowest maximum safe slope angle was 27 deg. Many potential key blocks were also identified. The results from the kinematic analysis support the existence of the key blocks determined by the block theory analysis. the purpose of the maximum safe slope angles for the key blocks is not to suggest the reduction of the current slope angle. Rather they are to show that instabilities exist and that external support may be needed in some places to prevent a major failure. The potnetial key blocks could become hazardious under external forces. Further analyses of the seven Cataracts Vista road cut will need to look into the effects of external forces, such as water forces and earthquake forces. Also, the key blocks and the potential eky blocks that were found in general through the block theory analysis should be physically found in general through the block theory analysis should be physically found in the ield before fial conclusions about the stability of hte site can be drawn.