Recent content by epongra2

GeoPave, Of course, but then there is that head scarp area. That flat failure surface at depth has to break towards the ground surface somewhere.

If indeed there is an old slide on the slope, then inherently there is at least one surface or layer that isn't horizontal, and it also happens to likely be the most critical with respect to future stability. Depending on the degree of weathering at the surface (i.e. time), knowledge of local...

Trend and plunge are for linear features (think striations on a slide plane or fault), while strike and dip are for planar features.

"With typical pile depth of 20' bgs (36' total, 7' rock embedment)" From the photo provided (and the apparent size of the landslide), the slide plane would seem to be much deeper than 13' below grade. Am I correct in assuming that the photo was taken near the middle of the slope failure...

With regards to the option of removing and recompacting the existing fill, is there not a soil profile at the top of the native glacial till? If so, that is a particularly easy way to verify you are through the fill and into the native below.

As a geologist, I enter test pits and large-diameter borings all the time. BigH is correct, though I don't know about the term microstructure... The test pit and large-diameter boring (24" or greater) is critical as an investigative tool in many of the areas where I work, where large...

Detrital coral? Loss of drilling fluids perhaps...

As an engineering geologist, frankly I'm reading some of these questions and cringing. It's pretty obvious you should get some input from a geologist, preferrably the one that put the geologic map together. If you are using a regional geologic map for your geology information, this data is...

Any construction activities in the area, i.e. pile driving, basement or underground parking excavations, dewatering wells, etc.?

The assessment of air photos and topographic maps is invaluable in the process, IMHO. Not enough people look at these, and I don't know why. Also, do not get into the all too familiar habit of simply looking at the subject property. If the site is on a large slide, the ground at the site may...

Here in So Cal "fault lines" or fault zones are often dealt with using a structural setback and therefore are an ideal location for parking lots.

With all due respect to the soils folks on these boards, rocks are often described as "soft". A good reference for this and other rock questions / issues is the USBR's "Engineering Geology Field Manual", which is available for download online at http://www.usbr.gov/pmts/geology/geoman.html...

If there is no documentation that the trench backfill was observed, tested and documented by a soils company, watch out.

moe333, My bad, I thought perhaps you might have been thinking of drilling via a method (air rotary, ODEX, etc.) other than coring and subsequently doing the camera work. I don't know which method takes less time. The video method provides output which is nice to include in a report and, it...

Why not do both? Seems like you would want the core for shear strength testing along the discontinuities and all the usual visual classifications. I reviewed a project where they cored and then subsequently lowered a down-hole camera into the borehole. Might want to talk with a company called...