compaction procedures for different types of soils

COMPACTION PROCEDURES FOR DIFFERENT TYPES OF SOILSSuryakanta | March 27, 2014 | Geotechnical, Soil | No CommentsThe embankments are constructed ith locally a!ailable soils, "ro!ided it #ul$ls the s"eci$ed re%uirements& 'rocedure o# com"action to be ado"ted ill de"end on the ty"e o# soil bein( used in construction& General (uidelines to deal ith com"action o#!arious ty"es o# soils #or attainin( o"timum dry density)relati!e density at minimum e*ort, ha!e been brie+y (i!en as under,Com"action o# SoilsCOMPACTION OF COHESION LESS GRAVELY AND SANDY SOIL:i- Sandy . (ra!ely soils should be com"acted ith !ibratory rollers& /# $nes are less in these ty"es o# soils, it can be com"acted ith minimum number o# "asses o# !ibratory rollers ithout strict control o# moisture to achie!e desired 0elati!e 1ensity&2ith hi(her "ercenta(e $nes, sandy and (ra!ely soils need to be brou(ht to 3MC le!el to (et e*ecti!e com"action& 4ni#ormly (raded sand and (ra!el are di5cult to be com"acted& To" layer o# sand and (ra!el remains loose in !ibratin( com"action& There#ore, in $nal "ass the roller should mo!e smoothly ithout !ibration& 1ry densities attained in $eld trials normally should be around M11) s"eci$ed 0elati!e 1ensity as obtained #rom laboratory tests and should #orm the basis #or s"eci$cation and %uality control&ii- 'oorly (raded sand and (ra!el ith Cu 6 2&0, should not be used in earthork #or the banks to sa#e(uard a(ainst li%ue#action under mo!in( loads or es"ecially due to earth%uake tremor& Generally, $ne sand is "rone to li%ue#action&COMPACTION OF SILTY CLAYEY SOILS:Silty soil is a $ne7(rained soil& These can be "lastic or non7"lastic de"endin( u"on the clay content in it& Silts and $ne sands ith hi(h ater content ha!e a tendency to under(o li%ue#action under !ibratin( rollin( due to the "ore ater "ressure (enerated by mechanical ork& Silty soils can be com"acted satis#actorily near about3MC either ith smooth rollers or !ibratory rollers& 8ibratory roller ill (i!e hi(h de(ree o# com"action and hi(her li#t& Com"action o# silty clays ill ha!e to be handled in a manner similar to clays&COMPACTION OF CLAYS:i- 2ater content "lays !ery im"ortant role in com"action o# clays& Main ob9ecti!e o# com"actin( clays is to achie!e uni#orm mass o# soil ith no !oids beteen the lum"so# clays& /# moisture content is too hi(h, roller tends to sink into the soil and i# too lothe chunks ould not yield to rollin( by rollers& :""ro"riate ater content i&e& 3MC o#the soil is in the ran(e o# about "lastic limit "lus to "ercent& Shee"s#oot rollers are most e*ecti!e in breakin( the clods and $llin( lar(e s"aces&ii- Thickness o# layer should not be more than de"th o# #eet o# roller "lus ;0 mm& 'ad #oot !ibratory roller ith drum module ei(ht o# 7tonne< total static ei(ht o# 11 tons- #or a li#t thickness o# =0 cm is #ound %uite e*ecti!e #or com"action o# clays& >or better results, initial rollin( ith static "ad #oot roller #olloed by 1; tons !ibratory roller can be tried& /n case o# such soils, the M11 and 3MC, as determined in the ?aboratory may not be !ery rele!ant and there#ore achie!able M11 and "racticable moisture content at hich such soils can be com"acted e*ecti!ely should be determined by conductin( $eld trials&