Choosing the conservative section for slope analysis 1

[geotechniqa]

Your geological map shows that you have a fault crossing your rock slope contour lines. If I want to consider a slope cross section for analysis for plane failure then what is the most dangerous cross section to consider as far as the fault is concerned. I believe that the section parallel to the fault.
But in this case slope cross section will not be perpendicular to the slope contours. Is this possible in slope stability analysis?




P.S. According to Hoek, Plane failure is potential only if : "The dip direction of the planar discontinuity must be within 20 degrees of the dip direction of the slope face". Does that mean : I measure the strike angle of each and if the GEOMETRIC difference between them is > 20 degree then no potential for planner failure.

 

[mudman54]

compare the strike of the fault to the "strike" of your excavation slope and if it is roughly parallel you have found either the favorable or unfavorable case when there is only 1 set of discontinuities depending on which way they dip. of course, if it really is a fault a larger zone of rock is broken and you might need to consider a circular failure to evaluate the stability. in all cases, do not rely on a geologic map but go out and take a look.

 

[BigH]

geotechniqa - was wondering if you have a geotechnical "mentor" in your office? . . . or is your company relying on you alone for the many facets you have started threads on?