MACKINTOSH PROBE TEST The The Mack Mackin into tosh sh Prob Probe e Test is a simp simple le and and econ econom omic ic test testin in meth method od to ath ather er preliminar!data on s"b s"r#ace conditions$ S"ch data ma!be ade%"ate #or the desins o# #o"ndations #or lihtl! loaded str"ct"res as this pro&ides a &er! economic method o# determinin thethickness o# so#t deposits s"ch as peat$ Objectives Mackintosh Probe test is carried o"t to determine the bearin capacit! o# soil$ The res"ltobtained #romthe test pro&ides a ro"h estimation o# the soil la!er at a point$ Background Soil strenth is de#ined as the abilit! o# the soil to carr! the load applied$ The strenth o# soilis o#ten related to the main characteri characteristic stic o# soil s"ch as cohesion cohesion and anle o# inte internal# rnal#ri rict ctio ion n Objective 'Collectin a dist"rbed soil sample #or rain(si)e anal!sis and soil classi#ication '*etermine s"b(s"r#ace stratiraph! and identit! materials present 'E&al"ate soil densit! and in(sit" stress conditions 'Estimate eotechnical parameters Theory The main p"rpose o# the test is to pro&ide an indication o# the relati&e densit!o# ran"lar deposit+ s"ch as sands and ra&els #rom ,hich it is &irt"all! impossibleto obtain "ndist"rbed samples$ The reat merit o# the test and the main reason #orits ,idespread "se is that it is simple and ine-pensi&e$ The soil strenth parameters,hich can be in#erred are appro-imate+ b"t ma! i&e a "se#"l "ide in ro"ndconditions ,her ,here e it ma! ma! not be poss possib ible le to obta obtain in bore boreho hole le samp sample les s o# ade% ade%"a "ate%"al te%"alit! it! like lik e ra&els+ ra&e ls+ sands+ sands + silts+ sil ts+ cla! containin sand or ra&el and ,eak rock$ The "se#"lness o# SPT res"lts depends on the soil t!pe+ ,ith ,i th #ine #i ne( (ra rain ined edsan sands ds i&in i&in the most most "se# "se#"l "l res"l res"lts+ ts+ ,ith th coars coarser er sands sands and and silt! lt! sands sands i&in i&in reas reason onab abl! l! "se# "se#"l "l res"lts+ and cla! and ra&ell! soils !ieldin res"lts ,hich ma! be&er! poorl! representati&e o# the tr"e soil conditions$ This test method pro&ides a dist"rbed soil sample #or moist"re contentdetermination+ #or identi#ication and classi#ication p"rposes+ and #or laborator! laborator! testsappropriate #or soil obtained obtained #rom a sampler that ,ill prod"ce a lare shear straindist"rbance in the sample$ Soil deposits contained ra&els+ cobbles cobbles or bo"lderst!picall! bo"lderst!picall! res"lt in penetration penetration re#"sal and damae to e%"ipment$ This test metho method d is "sed "sed e-tens e-tensi& i&el! el! in a rea reatt &ariet &ariet! ! o# eote eotechn chnica icalele-plo plora ratio tion n pro.ec pro.ects$ ts$ Man! Man! local local correlations correlations and ,idel! p"blished p"blished correlation ,hichrelate blo, co"nt+ or N(&al"e+ and the enineerin enineerin beha&ior o# earth,orks and#o"ndations are a&ailable$ Apparatus 'Borin Rods 'Rod Co"plins '/i#tin tools 'Penetration Cone 'Hammer
'0rench 'R"ler 'Markin tools
*isc"ssion The "se o# d!namic probin in con."nction ,ith trial pits and boreholes can prod"ce in#ormation at a lo, cost$ The Mackintosh Probe has a role in site in&estiations in so#t ro"nd d"e to the lo, cost and reasonabl! repeatable res"lts$ Mackintosh Probe testin in so#t soil has been reported #or depths o# 1 to 21 m 3Kon 245678akher et al$ 9112:$ In addition+ M i&es an indication o# soil parameters$ E%"ations ; and < con#irm the e-istence o# correlations bet,een M and N and ,hich E%"ations 29 and 2= con#irm the relationships bet,een M and c"$ The Mackintosh Probe ma! be s"ccess#"ll! "sed #or so#t cla!s ,ith "ndrained shear strenth 3c": less than ;1 kPa$ 0hen the Mackintosh Probe is "sed+ it is possible that a &al"e o# M reater than ;1 can be meas"red$ Ho,e&er+ the correlation bet,een c" and M ,hen c" R ;1 kPa and M > 61 is not disc"ssed in the paper and re%"ires #"rther research$The &al"e o# M #or so#t cla!s is hiher than the &al"es obtained #or N s"estin the M &al"e is more sensiti&e than N to &ariations in soil properties$ This s"ests that Mackintosh Probe testin co"ld be a more appropriate approach than SPT in &er! so#t soils$ I# ood correlations bet,een soil properties ha&e been established in an area+ Mackintosh testin co"ld be "sed #or additional ro"nd in&estiations$ It can also be "sed #or the interpolation o# soil properties bet,een boreholes to red"ce the cost o# in&estiations b! red"cin the n"mber o# boreholes$
Concl"sions
The Mackintosh Probe is a liht,eiht de&ice+ ,hich can be con&enientl! "sed #or the in&estiation o# so#t soil "p to depth o# 21 m$ It can be carried and "sed in di##ic"lt terrain ,ith poor access s"ch as s,amp! ro"nd+ as ,as the case in this research$ The res"lts o# Mackintosh Probin can be sho,n to be both repeatable and indicati&e o# soil strenth$ Correlations can be established bet,een M and N and also c" #or so#t cla!s and the Mackintosh Probe can be "sed rapidl! to assess the &ariabilit! o# soil conditions+ allo,in di##erent conditions to be identi#ied$ This allo,s e##ecti&e taretin o# an! s"bse%"ent boreholes or tests that ma! be re%"ired and also the interpolation o# soil properties bet,een boreholes$ *"e to the relati&el! lo, ener! hammer "sed to dri&e the probe into the ro"nd the Mackintosh Probe is not a s"itable tool #or "se in hard cla! or soils containin ra&el or cobbles$