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STONES IN COMPRESSION –
BOTH NATURALLY & MACHINE PLACED
by Dave Derrick
COMPRESS: To press
or squeeze (something) so that it is smaller or fills less space.
COMPRESSION: The act, process, or result of compressing
From: The Meriam-Webster on-line dictionary
In river engineering, we are talking about stones with a sloped side facing upstream so that flow (water pressure) pushes against the sloped face & pushes the stone down into the bed of
the stream (in compression).
Several river folk performed literature searches to see if anyone had analyzed
how much more stable a stone in compression is compared to a similar stone that was not in compression, but
no one has done that research !!! Sounds like an important thesis to me.
STONES, & OTHER OBJECTS,
NATUALLY IN COMPRESSION
Stones naturally in compression
With “slabby” stones, “B” axis
of stone is almost always parallel
to flow. “A” axis (longest side) of
stone is perpendicular to flow. Big Piney
Creek, AR.
Stones are imbricated (overlaying each other) like shingles on a roof.
A Hydraulic Cover Stone (HCS) dug into the streambed substrate for stability. Upstream sloped face of HCS is in
compression & forces the HCS into the bed. The downstream wake (surface modulation) is the “Hydraulic Cover”.
Flow
HCSFlow force Force
NATURAL-Looking across. Hard to believe the stream moved these stones. Bedload !! High flow compresses stones into the bed of the stream
NATURAL-RILEY COUNTY, KS. - PIX BY DERRICK 7-19-2012
Flow force
Force
NATURAL-Looking US @ rocks in compression. High flow hitting top stone pushes it down into the bottom (footer) stone & into the bed.
NATURAL-RILEY COUNTY, KS. - PIX BY DERRICK 7-19-2012
FLOOD IN PARK-Looking DS @ picnic table in compression.
FLOOD IN PARK AREA-CATFISH CR. PIX DAVE DERRICK-8-5-2011
Flow
FLOOD IN PARK-Accelerated flow velocities around vehicle results in a scour hole. Water was several ft deep across entire floodplain.
Sloped angle of car into flow resulted in the car being pushed into the ground instead of being carried DS during the flood.
FLOOD IN PARK-CATFISH CR. PIX BY REBECCA KAUTEN-8-4-2011
FLOOD IN PARK-Looking US. Auto blocked & split flow. Note “shadow” deposition DS of car.
FLOOD IN PARK-CATFISH CR. PIX BY REBECCA KAUTEN-8-4-2011
GOAL & FUNCTION-BASED DESIGN FOR RIPARIAN & STREAM SYSTEMS
THE EIGHTEENMILE CREEK PROJECT
PHASE II CONSTRUCTED JUNE 18-20, 2007
by Dave Derrick
Vic with a sloped face stone that will be perfect for placing into compression when the sloped side is facing upstream.
Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick
Vic with a sloped face stone that will be perfect for placing into compression when the sloped side is facing upstream.
Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick
Flow force
Force
Looking DS @ a group of several HCS. US stone in compression
Construction-18 Mile Creek, Phase II-June 2007, Pix-Vic DiGialomo
Looking US @ same group of 5 Hydraulic Cover Stones
Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick
THE EIGHTEENMILE CREEK PROJECT
A LINE OF STONES IN COMPRESSION THAT WILL PROTECT THE
FISHERMAN’S WALKING PATH
Flow from left, looking @ stones in compression.
Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick
See the footer stone?
Attack Flow
Close-up of fisherman’s path stones in compression. Flow hits angled upstream face of stone, which pushes that stone into the footer stone, which is then pushed down
into the bed of the stream (compression), resulting in a very stable structure.
Construction-18 Mile Creek, Phase II-June 2007, Pix by Derrick
See the footer stone?
Attack Flow
It’s all about the fishing!!!!
Construction-18 Mile Creek, Phase II-Fall 2007
This PowerPoint presentation was developed & built by Dave Derrick.
Any questions or comments, call my personal cell @ 601-218-7717, or email @ [email protected]
Enjoy the information!!
KAYLYN LOUISE DERRICK, AGE ½.
