Need help with a difficult sketch

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Need help with a difficult sketch

Postby GroundquestMSA » Dec 24, 2012 12:37 pm

60' tall, 20' wide passage filled with breakdown and clay. The route of travel alternates from over, under, or through the breakdown. Sometimes two or more routes are possible. I have about 2000' of this "problem" passage, how do I sketch it? A plan view showing the theoretical location of the actual passage walls would more accurately describe the nature of the cave, but wouldn't help much with route finding. A plan view showing the actual route of travel through the visible passage would be a sinous up and down affair, while the cave is actually big, level, straight. I've worked out what I think is a compromise, which I've shown a segment of below, but I'm still unsure of it. Tell me if you think it makes sense. Also, do you have any suggestions for x-sections in this kind of passage? Should I try to show the traversable passage shape only or include its assumed relation to the rest of the filled passage? Or...should I try to include a profile?

I know these are very common issues, and I thank you for your patience in explaining solutions to a novice.

click to see the entire sloppy sketch
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Re: Need help with a difficult sketch

Postby Chads93GT » Dec 24, 2012 10:45 pm

Arrows denote water. Is there? Draw breakdown for walls when there are no solid walls. Just like you are doing. Is his sketch the floor plan. A cross section. Or the full profile?
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Re: Need help with a difficult sketch

Postby GroundquestMSA » Dec 25, 2012 11:40 am

This is an imaginary plan view. I haven't started surveying this part of the passage yet, but this little sketch was intended to portray the type of passage encountered. There is a stream.
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Re: Need help with a difficult sketch

Postby Chads93GT » Dec 25, 2012 11:45 am

Well you will only depict the walls where the breakdown is that you can see in that case. Drawing 10' of breakdown to an imaginary wall wouldn't be correct either because you won't truly know where a solid wall is or how thick the breakdown actually is. Therefore your passage will be very narrow with the breakdown walls drawn in. Looks good
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Re: Need help with a difficult sketch

Postby JP McLendon » Dec 25, 2012 2:02 pm

In my opinion, you're absolutely on the right track. It's clear to me that's it a plan view with the slope symbols. Breakdown walls where the wall is BD and solid lines where the wall is solid, and dashed lines for presumed walls. It's not typical that you can tell where the actual walls are beyond the breakdown and fill so the presumed passage dimensions aren't usually shown, but if you can tell in your passage, I think it adds value and information to the map to show the presumed walls. I would suggest a note beside the passage segment, perhaps "large borehole with approximate dimensions of X by X, mostly filled with mud & breakdown, presumed walls shown where apparent."
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