Page 17 - West Virgina 811 2019 Issue 3

Pan three: Soil classilicalion
adly, as many as 400 workers tracture and destabilize soil that was Type c. The CI’ should also check the
am med mi ,,.,3,,m1 .l,.,.,m.i initially considered stable. sides ot the excavation tar layerecl
w0,kp,,. am ,.E,;.,“..iy ,,.i,,mi Type A _ Defined DD mlmm ml with systems, water, utilities, and signs ot
in trenches and excavations an unmnfimd mm DDDDDD mm th previously disturbed soils The CI’
across the U.S. each year. one reason: D‘ 1 5 DD“ DDD DDDDED ‘ODD D; Dmil rt}-Is! 3150 be v-it-lax-I for svumes 0*
M‘"‘Y P‘°P‘E WEE‘ “W ‘’’*‘5*‘‘ °‘ As a practical matter, Type A soil is "‘b'““““‘
5°“ Tl“ FMS‘ 0"“ ‘“"“ “’°‘ “‘ 5°" also race because reviousl disturbed Manual Tests - There are a number
W’=‘S}‘5 "’““’*°“ 9” ““d 140 P°““d*'- soils or soils sllbjgcl In vibryatidn oi diiterent manual tests included in
A ‘"5" Ya“ "‘ 5°“ “E” ‘”“8}‘ “‘"‘°"‘ trom construction equipment trattic the OSHA standard
4,000 pounds, as much as an suvi As I .. . ’ . .' '
a result, when a trench cave-iri occurs, {‘T‘;‘;':’A’3,“'°" “'2 d"q“”l'f‘“d E” bmg The Dry strength, Thread, Dr Ribbun
there are usually deaths or very serious ‘ Tests can he used to determine it a soil
» i - T e B - Detined as moderatel is cohesive or ranular.
miunes. yp y g
h.-.’lN. d-T A, . .
An lmpnrlanl responsibility tor the E“ IN"? 7:‘ D ‘?‘T“‘ 5%’ _ 3.: W“ The Thumb l-enetration Test relies
,. . ,, . __ unotas a as ype set. D . LDD .

competent Person (discussed eavily upon expenence of
in part one of this series) is ‘Soil Type C - Detined as the least the person pertorming the test. ln
classification." It is the tirst step in cohesive soils, having an uncontined the Thumli Fenzrrztlon Test, the
choosing a protective system, and compressive strength less than 5 tons "Competent Person" gathers a handiul
the law requires it Even it a soils per square toot This includes wet, ot treshly excavated soil and press-es
engineering service has been identitied granular, Dr lDD§E soils. The best way his/ her thumb into the material. Type
tor a pmjzcl, the "Competent Person" is to remember Type c is to Ihlnk ot the A sails zzqulre a great nrnnunt of eitart
still required to classiiy the soil. "C” standing tar crummy. lt is the to indent the soil. Type B soils can be

l.-.-bl t t l.Tli . d dv’h d .T

we as :i.::
of diiterent types oi soil. OSHA is Tom mm PDDDD, [Ch DID DDDD ’ ’ ‘
concerned with just tour types DD DIEM DD 123;‘ DDD DMD! Did Due Pocket Penetrometers and shearvanes
stable Rock . Defined as natural nl-Ema! test or the sail ““ be W“ “’ “°“""‘“‘ “‘°

. i ' approximate uncontined compressive
‘°““ "““"“‘ "‘“‘‘°’ “W ““ ‘"3 Visual Test - To make a visual test stren th ot soils
excavated with vertical sides and will “DD ,.COmDD‘Dm PDNm,, DDDDNDD ' ’ ’ 5 ’ ’ ’
remain intact while exposed stable DD“ D D DD DDDDD DXDDDDDDD DD“ {hm There is one method of soil
ruck is extremely rare ln tact, less than ’ I _ . . _ _. classification that the CI’ can employ

. . remains in large clumps is cohesive,
two percent of the sol] in the U. s. is and D DDDDDMD TYPE A DD TDDD 3 DD“ to avoid all these tests l-le/ she can
classified as stable Rock ln additiun, . » assume the ”wDrs2 me" scenanu and
. (depending upon other tactars) soil .

the process of excavating with saws, ‘hm HDWD Dm D‘ D“ DXDDDDDDD Ducm DD classiiy all soil as Type c. The trenoh
li k .-,d ‘ , ., "lll’kl ’ ti th lie.-l ed,

'9“ E" >’““’““‘ “C "“ ‘ E Y granular, loose, or wet, and is probably jgumfisgfiyl D“ DEED
7 many contractors and utilities lake the
7 pnslfiun that every soil they WDl'k in

A is Type c. That helps In simpliiy the
11%“ entire trenching and excavation safety
4 ,_ , , gr I-
/il,‘,/ X ‘-x; - process immensely '
Editors Niitc This )5 the third ii/fviii
articles iri this scncs tltiit tliscttsscs speclfir
5Iz'p5 fh/1! com‘mL‘l‘l7Y5 and IAHHUIS um
take to hclp msur? the srifcty a]t‘hel'r
(D -’ \/ pcrsoitriel ODWlJH5Iy, this is hit iwcriiicni
D iiftlic subject‘ It is iiiipossitlc to pmpcrly
cover the topic iii jusflflur rcliiiiiicly sltort
iirticlcs coiitriictiirs iiiid titilities iiirolrcd
‘ H1 iiitdeigroahd IA/01* iiiill rieeti additiiiitril
tiiziitirig tii )rl51lIZ woitrcv siifcty.
xtiattii aiiiiiioniici Jim! cxaiipiciyii MIN!!!/H iisiiiiii (M! ii p«‘v/0vlrltdI0r1CN‘Yrllmt‘5olVPypfl 2019' we 3 WED mm Du , 15