FLOOD00566

• County: Statewide
• Title: Nature's Building Codes - Geology and Construction in Colorado
• Date: 8/1/1979
• Prepared For: State of Colorado
• Prepared By: DNR
• Floodplain - Doc Type: Educational/Technical/Reference Information

Mitigation

Construction In areas susceptible to cot lapse Is difficult.
Some sol Is .11 I col lapse under their o.n .elght If _etted.
Two construction techniques are possible in this case: 1)
provont "otting at the soilS tor the lifetime of the
structure, or 2) precol lapse the sol Is prior to construction
by deep soak.ing ot the area. Soils which ...111 collapse with
the addition of heavy structures alone 'flIght be del/sloped
success full y 1ft 1 th '19ht "'9 I gh t I mprQ\le.1l9n t s. I n some cases
the problem sol I may be shallow enough to excavate, or the
building foundation may be placed below the troublesome 5011
in more suitable material. Any technique of development Is
etfecthe only after careful analysis of the conditions and a
thorougn understandIng ot the process Is gaIned. Correctl~e
techniques can be costly. GI...en no other choice, thIs m!lY be
less e~pensl~e than continual repair or rebuIlding of the
structure. Jeologlc In~estlgations and testing can re~eal
col lapsing sol Is as .el I as sites subject to to settlement
for natural or man-caused reasons.

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These ho photos shoiol hydrocompactlon of salls along the
proposed Interstate 70 alignment near RI f Ie. Note concentrIc
rIngs around the pond and through a test road embankment.

Land Use

The only lo!lnd uses ioIhlch create no-risk situations are
agrIcultural and open space. Land uses that Involve
structural Improvement on the land surface may generate
costly maIntenance and even destruction of the development.
MinImum structural development, such as a storage yard.
constitutes a relatl~ely sate use ot land subject to collapse
or sott lement.

Case History

^ Carbondale. Colorado. rancher's stock _aterlng pond
excavated In a pasture collapsed because of hydrocompactlon.
A bOwl-shaped depression 60 feet across and 8 teet deep
resulted when ne attempted to pond _atar In hIs field. The
soIls _ere so permeable that the pond .ouid not hold _ater,
and the _etted sol Is under the pond col lapsed. Many roads
and other Improvements In the vIcinity have been destroyed
or damaged by soaking ot collapsible, lOll density soils.

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Tests permitted proper high.ay design and construction,
avoIding future repaIrs.

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