natgillin/translations-raw huggingface dataset:
The range of acidity in peat is very wide and so the pH value of most peats varies from 2 to 6 [7].
Takva su tla vrlo vlaknasta i izuzetno kisela, a pH većine njih je od dva do šest [7].
The in situ void ratio of fibrous peat is very high due to hollow cellular fibres and high initial water content [8].
Koeficijent poroznosti vlaknastog treseta u prirodi vrlo je visok zbog šupljih vlakana i visokog početnog udjela vode [8].
According to Kogure et al [9], peat contains the inner and outer void spaces that cause higher settlements compared to other soils.
Kogure i suradnici [9] tvrde da treset sadržava unutarnje i vanjske šupljine koje uzrokuju jače slijeganje nego u ostalim vrstama tla.
The void ratio as high as 25 can be found in fibrous peat whilst the void ratio as low as 9 is possible for a denser amorphous peat [10].
Koeficijent poroznosti vlaknastog treseta može biti čak 25, dok gušći amorfni treset može imati koeficijent poroznosti 9 [10].
Mesri et al. [11], define these superficial deposits as soil with a very high in situ water content of 500 % to 2000 %, which corresponds to the in situ void ratio ranging from 7.5 to 30, respectively.
Mesri i suradnici [11] te su površinske naslage klasificirali kao tla s vrlo visokim prirodnim udjelom vode (od 500 % do 2000 %), čemu odgovara koeficijent poroznosti u prirodi od 7,5, odnosno 30.
Natural fillers play a vital role in enhancing the bond in the cementation reaction of soil mixing.
Prirodna punila bitno pospješuju povezivanje u reakcijama tijekom ojačavanja tla miješanjem s dodacima.
So these high void ratios can lower the bearing capacity, which is why the peat is considered as an unsuitable soil for foundations in its natural state.
Nema kemijskih reakcija produkata hidratacije cementa s česticama pijeska, no taj proces ojačava tlo jer smanjuje koeficijent poroznosti treseta stabiliziranog cementom [12].
This ground modification technique has been used for many diverse applications including building and embankment foundations, retaining structures, liquefaction mitigation, temporary support of excavations, and water control.
Rabi se pri gradnji temelja zgrada ili nasipa te potpornih konstrukcija, za ublažavanje opasnosti od likvefakcije, kao privremena mjera potpore pri iskapanju te za kontrolu vlažnosti.
In this method, hydraulic mineral binders are mixed with in situ peat to form a columnar reinforcement in the deep peat ground.
Metoda podrazumijeva miješanje hidrauličkih mineralnih veziva s tresetom na terenu i stvaranje "stupova" koji ojačavaju dubinske slojeva tla.
Since peat has a high water content, it can provide water that is required for binder reactions.
Treset ima visoki udio vode, što znači da je osigurana voda potrebna za reakcije vezanja.
Therefore the dry mixing method is more effective for peat soil improvement compared to the wet mixing method [14].
Stoga je za ojačavanje tresetnog tla učinkovitije suho nego vlažno miješanje [14].
Although a variety of laboratory and field studies have shown that cement is very effective in improving the bearing capacity of fibrous peat [5-6, 15], the failure of these columns is often attributed to unsuitable type and insufficient dosage of binder that is added to the soil [12].
Iako su mnoga laboratorijska i terenska istraživanja dokazala da cement učinkovito poboljšava nosivost vlaknastog treseta [5-6, 15], urušavanje "stupova" pripisuje se neodgovarajućoj vrsti ili nedovoljnom udjelu veziva dodanog tlu [12].
Thus, there is a need to ameliorate the strength properties of stabilized peat columns.
Stoga bi trebalo povećati čvrstoću "stupova" u stabiliziranom tresetu.
The peat is mostly considered as a frictional material due to high fibre content [16].
Treset se smatra materijalom visokog koeficijenta trenja jer sadržava mnogo vlakana [16].
But this high friction angle will not demonstrate high shear strength because the fibres are filled with water and gas.
No velik kut trenja ne znači i veliku posmičnu čvrstoću jer su vlakna puna vode i plina.
In laboratory, the most common test for determining the undrained shear strength (su) is the uniaxial compression strength (UCS) test.
Najčešće laboratorijsko ispitivanje nedrenirane posmične čvrstoće (su) jest ispitivanje jednoosne tlačne čvrstoće (UCS - Uniaxial Compressive Strength).
The undrained shear strength of a cohesive soil is equal to one-half of the uniaxial compressive strength (qu).
Nedrenirana posmična čvrstoća kohezivnog tla jednaka je polovici jednoosne tlačne čvrstoće (qu).
This test has been found to be an effective and economical method to determine the binder content that is required to obtain a specific shear strength.
To se ispitivanje pokazalo učinkovitom i ekonomičnom metodom za određivanje udjela veziva potrebnog da se postigne željena posmična čvrstoća.
It is obvious that high organic content of peat can impede the stabilization process and normally peat needs greater quantities of binder than do inorganic soils.
Očito je da visok udio organskog materijala u tresetu ometa stabilizacijski proces, pa je za stabilizaciju treseta potrebno više veziva nego za stabilizaciju anorganskog tla.
Thus, in order to neutralize this effect, the quantity of binder needs to exceed the threshold as shown in Figure 1 [5].
Kako bi se to djelovanje poništilo, količina veziva mora biti veća od granice, kako je prikazano na slici 1., [5].
General Relationship between binder dosage and shear strength in peat soils, EuroSoilStab [5]
Opći odnos udjela veziva i posmične čvrstoće tresetnog tla, EuroSoilStab [5]
Several researchers have conducted laboratory experiments to study the effect of binders on the shear strength of peat soils.
Nekoliko istraživača provelo je laboratorijska ispitivanja kako bi objasnili učinak veziva na posmičnu čvrstoću tresetnog tla.
According to Wong et al [17] the uniaxial compressive strength of stabilized peat increases to 142.5 kPa at the minimum dosage of 250 kg/m3 for 75 % cement and 25 % slag, and to 178.6 kPa using 300 kg/m3.
Wong i suradnici [17] tvrde da se jednoosna tlačna čvrstoća stabiliziranog treseta povećala na 142,5 kPa nakon ojačanja s najmanje 250 kg/m3 smjese sastavljene od 75 % cementa i 25 % zgure te na 178,6 kPa uz 300 kg/m3 te smjese.
Hebib and Farrell [15] stabilized fibrous peat and declared that the minimum dosage for peat soil activation is 150 kg/ m3.
Hebib i Farrell [15] stabilizirali su vlaknasti treset i zaključili da je najmanji udio potreban za aktivaciju tresetnog tla 150 kg/m3.
According to Chen and Wang [18], the peat strength of 300 kPa could not be reached at the cement ratio of up to 30 % with the deep mixing method at a foundation reinforcing project on peat.
Chen i Wang [18] tvrde da proces dubinskog miješanja s cementom u udjelu od 30 % nije pomogao u projektu ojačavanja temelja u tresetu jer čvrstoća nije dosegnula 300 kPa.
In general terms, parameters that affect significantly the shear strength of cement stabilized soil are the water content, liquid limit, sand and fines content, density, the amount of added cement, curing time, and pH value [19].
To dokazuje da na posmičnu čvrstoću treseta stabiliziranog cementom znatno utječu sljedeći parametri: udio vode, granica protoka, udio pijeska i sitnih čestica, gustoća, količina dodanog cementa, vrijeme njege i pH [19].
Therefore, choosing an appropriate quantity of binder is of decisive significance for the improvement of peat soils.
Stoga je ključno odrediti odgovarajuću količinu veziva želimo li ojačati tresetno tlo.
Engineering properties of fibrous peat originating from southern Malaysia are studied in this paper.
U članku se prikazuju ispitivanja geomehaničkih svojstava vlaknastog treseta iz južne Malezije.
In addition, series of uniaxial
Proveden je niz
compressive strength tests have been carried out in order to evaluate the effect of various natural fillers on the uniaxial compressive strength (UCS) of the cement treated fibrous peat (hereinafter called cement peat) at different curing times.
ispitivanja jednoosne tlačne čvrstoće kako bi se odredio učinak raznih prirodnih punila na jednoosnu tlačnu čvrstoću (UCS) treseta ojačanog cementom (u daljnjem tekstu: cementnom stabiliziranog treseta) u ovisnosti od vremena njege stabilizirane mješavine.
In fact, the study focuses on finding an optimum dosage of natural fillers at which the highest shear strength can be achieved.
Članak nastoji odrediti optimalan udio prirodnih punila za postizanje najveće posmične čvrstoće.
2. Laboratory experiments
2. Laboratorijska istraživanja
In order to evaluate the undrained shear strength of the soil, vane shear tests were performed at different locations.
Kako bi se odredila nedrenirana posmična čvrstoća tla, na različitim mjestima su izvedeni pokusi s krilnom sondom.
This peat is famous for its low undrained shear strength and compression modulus [20].
Ta su tresetna tla poznata po maloj nedreniranoj posmičnoj čvrstoći i niskom modulu stišljivosti [20].
The laboratory testing programs comprised basic tests on undisturbed peat specimens, and uniaxial compression tests on stabilized specimens.
Laboratorijski programi ispitivanja uključivali su osnovna ispitivanja neporemećenih uzoraka treseta i ispitivanja jednoosne tlačne čvrstoće stabiliziranih uzoraka.
An ordinary Portland cement (hereinafter called cement) was used in the study as the binding agent.
Vezivo koje je korišteno pri ispitivanjima bio je običan portland cement (u daljnjem tekstu: cement).
As shown in Figure 2, four types of natural fillers containing well graded sand (SW), poorly graded gravel (GP), coarse poorly graded sand (C-SP), and fine poorly graded sand (F-SP), were used in this study.
Korištene su i četiri vrste prirodnih punila, kako je prikazano na slici 2: dobro granulirani pijesak (SW), slabo granulirani šljunak (GP), grubi slabo granulirani pijesak (C-SP) i sitni slabo granulirani pijesak (F-SP).
Different materials used in this study
Različiti materijali korišteni pri ispitivanju
Preparation of samples
Priprema uzoraka
In this study, samples were prepared based on the EuroSoilStab design guide [5].
Uzorci su pripremljeni prema smjernicama priručnika EuroSoilStab [5].
According to this design guide, the binder quantity is expressed in kg/m3 relative to the wet mass of the
Taj priručnik količinu veziva navodi u kg/m3 u odnosu na masu vlažnog treseta.
peat.
Primjerice, ako je gustoća
For instance, if we take that the density of peat is 1000 kg/m3 and if the prescribed cement quantity is 300 kg/m3, then 300 gr of cement are needed for each 1000 gr of wet peat.
promatranog treseta 1000 kg/m3, a propisana količina cementa 300 kg/m3, za svakih 1000 g vlažnog treseta potrebno je 300 g cementa.
After this, the quantities of natural fillers are calculated based on weight of the wet cemented peat.
Zatim se količina prirodnog punila izračuna na temelju mase vlažnog cementom stabiliziranog treseta.
It should be noted that all stabilized peat samples used in this study were at their original natural moisture content of about 495 % (± 5 %).
Važno je napomenuti da su svi uzorci stabiliziranog treseta u ovom istraživanju imali prirodan udio vlage od 495 % (± 5 %).
Therefore, no water was added to the natural peat soil during mixing with cement and different natural fillers.
Prirodnom tresetu nismo dodavali vode pri miješanju s cementom i raznim prirodnim punilima.
For the curing process, the stabilized peat specimens were kept in the closed and covered PVC moulds and maintained during the curing time at the temperature of 25o C.
Tijekom procesa njege uzorci stabiliziranog treseta čuvani su u zatvorenim i pokrivenim PVC kalupima pri konstantnoj temperaturi od 25oC.
The air-dried peat was first passed through a 2 mm sieve in order to remove coarse materials such as roots and large fibres.
Treset sušen na zraku najprije je prosijan kroz sito s otvorima od 2 mm, čime su otklonjeni grubi materijal poput korijenja i većih vlakana.
Water was added to achieve the natural water content of the peat, which was 495 %.
Dodana je voda kako bi udio vode bio prirodan za treset, 495 %.
A kitchen mixer was used to mix and homogenize the wet peat.
Vlažni je treset miješan s kuhinjskim mikserom dok smjesa nije postala homogena.
The quantity of cement for each specimen was 300 kg/m3 relative to the weight of wet peat at its natural water content.
Za svaki uzorak korišteno je 300 kg/m3 cementa u odnosu na masu vlažnog treseta s prirodnim udjelom vode.
Natural fillers were added to the cement peat at binder dosages of 50, 75, 100, 125, 150, 175 and 200 kg/m3, relative to weight of the wet cemented peat.
Vezivna prirodna punila dodana su cementom stabiliziranom tresetu u udjelima od 50, 75, 100, 125, 150, 175 i 200 kg/m3 u odnosu na masu vlažnoga uzorka.
Various compositions of natural fillers used in testing are depicted in Table 1.
U tablici 1. prikazan je sastav prirodnih punila rabljenih pri ispitivanju.
Tests schedule
Prikaz ispitivanja
Methods of testing
Metode ispitivanja
In order to evaluate the undrained shear strength of stabilized peat specimens, various uniaxial compression tests were conducted in accordance with BS 1377:1990: Part 7: section 7 [21].
Da bi se odredila nedrenirana posmična čvrstoća stabiliziranih uzoraka treseta, provedena su različita ispitivanja jednoosne tlačne čvrstoće u skladu s BS 1377, 1990., sedmi dio, sedmo poglavlje [21].
Number of tests Composition of soil specimen
Broj ispitivanja Sastav uzorka tla
Note: OPC - Ordinary Portland cement
Napomena: OPC - obični portland cement
axial load was applied vertically at the constant rate of 1.42 mm.min1,as shown in Figure.
1,42 mm/min, kako je prikazano na slici 3.
3. Care was taken to ensure that both ends of the specimen are flat to minimize bedding error, especially in case of stiffer samples.
Oba kraja uzorka bila su ravna kako bi se smanjila pogreška mehanizma za nanošenje opterećenja, osobito kod krućih uzoraka.
The test was considered complete either when a definite peak was obvious, or when the 20 % strain was reached, whichever occurred first.
Ispitivanje je završavalo čim bi maksimum postao očit ili čim bi se postigla deformacija od 20 %.
Three main types of failure occurred during the testing: plastic failure in which the specimen bulges laterally into a barrel shape, brittle failure in which the specimen shears along one or more surfaces, and an intermediate failure [22].
Tijekom ispitivanja uočena su tri najvažnija oblika popuštanja uzoraka: plastično popuštanje, odnosno pomicanje i bačvasto iskrivljenje uzorka, krto popuštanje, odnosno posmik uzorka u odnosu na jednu ili više površina i prijelazno popuštanje [22].
3. Results and discussions
3. Rezultati i diskusija
Basic results
Osnovni rezultati
It was established by close examination that the ground water table is at 0.5 m below the ground level, which shows that the
Nakon provedenog ispitivanja dobiveno je da je razina podzemne vode bila ispod 0,5 m od površinskog sloja, što
peat has a high water holding capacity.
znači da treset ima veliku sposobnost zadržavanja vode.
The physicochemical properties of peat samples and various properties of natural fillers were determined in laboratory based on the BS and ASTM standards [21, 23], as shown in Tables 2 and 3, respectively.
Fizička i kemijska svojstva uzoraka treseta te različita svojstva prirodnih punila određena su u laboratoriju prema BS i ASTM standardima [21, 23] te su prikazana u tablicama 2. i 3.
The chemical composition of the cement, based on the manufacturer's information, is summarized in Table 4.
Kemijski sastav cementa prema deklaraciji proizvođača predstavljen je u tablici 4.
Particle size distribution curve of fibrous peat and fillers
Granulometrijske krivulje vlaknastog treseta i punila
Average value
Prosječna vrijednost
Moisture content (BS 1377, 1990., Part 2) Bulk density (in situ)
Udio vlage (BS 1377, 1990., drugi dio) Prostorna masa (na terenu)
Classification (ASTM 5715-00)
Klasifikacija (ASTM 5715-00)
Fibrous
vlaknast
Classification (von Post)
Klasifikacija (prema von Postu)
Specific gravity (BS 1377, 1990., Part 6)
Specifična gustoća (BS 1377, 1990., šesti dio)
Organic content (BS 1377, 1990., Part 3)
Udio organske tvari (BS 1377, 1990., treći dio)
Fiber content (ASTM, 1997.
Udio vlakana (ASTM, 1997.
Void ratio (BS 1377, 1990., Part 4) Undrained shear strength-vane shear test (BS 1377, 1990., Part 9)
Koeficijent poroznosti (BS 1377, 1990., četvrti dio) Nedrenirana posmična čvrstoća - pokus krilnom sondom (BS 1377, 1990., deveti dio)
Undrained shear strength-uniaxial compressive strength test (BS 1377, 1990., Part 7)
Nedrenirana posmična čvrstoća - ispitivanje jednoosne tlačne čvrstoće (BS 1377, 1990., sedmi dio)
Properties of peat soil used in this study
Osobine ispitivanoga tresetnog tla
Uniaxial compression test using 5kN load frame
Ispitivanja jednoosne tlačne čvrstoće opterećenjem od 5kN
Chemical compositions of cement used in this study
Kemijski sastav cementa korištenog pri ispitivanju
Uniaxial compression strength results
Rezultati ispitivanja jednoosne tlačne čvrstoće
If the cement quantity of 300 kg/m3 is added to the wet peat specimens after 14 days of curing, the density increased from 1 Mg/m3 for undisturbed peat to the maximum density of about 1.37 Mg/m3.
Nakon vremena njege od 14 dana u uzorcima s 300 kg/m3 cementa u odnosu na masu vlažnog treseta gustoća se povećala od 1 Mg/m3 (gustoća neporemećenog treseta) na oko 1,37 Mg/m3 (maksimalna gustoća).
The density of all specimens remained approximately constant after 90 days of curing.
Gustoća svih uzoraka nakon 90 dana njege ostala je jednaka.
Furthermore, the moisture content of cement peat was 125 % after 14 days of curing, and it showed a very small reduction even after 90 days.
Nakon 14 dana njege udio vlažnosti cementnom stabiliziranog treseta bio je 125 %, a nakon 90 dana vrlo se malo smanjio.
It should be noted that the moisture content of all specimens mixed with different fillers showed a very small reduction (maximum 3 %), compared to 14 days curing.
Napominjemo da se udio vlage svih uzoraka miješanih s raznim punilima nije znatno smanjivao (najviše 3 %) u odnosu na uzorke nakon 14 dana njege.
The highest uniaxial compressive strength (UCS) of 115.2, 163.7 and 170.93 kPa was reached in stabilized peat specimens with cement only at a binder dosage of 300 kg/m3 at 14, 28 and 90 days of curing, respectively.
Najveća jednoosna tlačna čvrstoća od 115,2, 163,7 i 170,93 kPa postignuta je samo na uzorcima stabiliziranog treseta s udjelom cementa od 300 kg/m3 nakon vremena njege od 14, 28, odnosno 90 dana.
As a comparison, the UCS values obtained in this study were almost the same as those of the stabilized peat, which was found to be 178.6 kPa using the binder dosage of 300 kg/m3 with 75 % cement
Kao usporedbu navodimo da su vrijednosti mjerenja jednoosne tlačne čvrstoće u našim ispitivanjima bile gotovo jednake onoj od 178,6 kPa koju su Wong i suradnici [17] izmjerili za stabilizirani treset s udjelom veziva od 300 kg/m3, od čega 75 % cementa i 25 % zgure.
and 25 % slag, according to Wong et al [17].
Hebib i Farrell [15] u svojim su istraživanjima došli do sličnih rezultata.
They have also established that the binder dosage of 250 kg/m3 cement can increase the UCS of untreated peat up to 1100 kPa, which is significantly higher compared to this study.
Također su otkrili i da udio veziva od 250 kg/m3 cementa može povećati jednoosonu tlačnu čvrstoću neobrađenog treseta na čak 1100 kPa, što je mnogo više od onoga što smo naveli u našim istraživanjima.
It clearly indicates that UCS of stabilized peat is very much site dependent.
Iz navedenoga se jasno vidi da jednoosna tlačna čvrstoća stabiliziranog treseta ovisi o lokalitetu.
Figure 5 shows a typical relationship between the UCS and axial strength of cement peat at the constant cement dosage of 300 kg/m3 by mass of wet peat mixed with well graded sand at the dosage of 125 kg/m3 by mass of wet peat, during 90 days of curing.
Slika 5. prikazuje karakterističan odnos jednoosne tlačne čvrstoće i vertikalne deformacije stabiliziranog treseta uz stalan udio cementa od 300 kg/m3 u odnosu na masu vlažnog treseta, pomiješanog s dobro granuliranim pijeskom u omjeru od 125 kg/ m3 u odnosu na masu vlažnog treseta i nakon 90 dana njege.
The UCS of undisturbed peat was found to be 20 kPa, which is equal to the average shear strength of 11 kPa achieved in situ using the vane shear test.
Jednoosna tlačna čvrstoća neporemećenog treseta bila je 20 kPa, što je odgovaralo posmičnoj čvrstoći od 11 kPa izmjerenoj na terenu pokusom krilnom sondom.
Relationship between uniaxial compressive stress and vertical strain of stabilized fibrous peat specimens
Njihove su jednoosne tlačne čvrstoće 177,8 odnosno 126,1 kPa.
Filler 1 SW
Punilo 1 SW
Filler 2 GP
Punilo 2 GP
Filler 3 C-SP
Punilo 3 C-SP
Filler 4 F-SP
Punilo 4 F-SP
CU (Uniformity coefficient) CC (Coefficient of curvature) e min (Minimum void ratio)
CU (koeficijent nejednolikosti) CC (koeficijent zakrivljenosti) e min (najmanji koeficijent poroznosti)
e max (Maximum void ratio)
e max (najveći koeficijent poroznosti)
GS (Specific gravity) gd(max) (Maximum dry density)
GS (specifična gustoća) gd(max) (najveća suha gustoća)
Φ (Angle of internal friction)
Φ (kut unutarnjeg trenja)
SW: well graded sand, GP: poorly graded gravel, C-SP: coarse poorly graded sand, F-SP: fine poorly graded sand emin determined as per ASTM D 4253; emax determined as per ASTM D 4254; gd(max) determined as per ASTM D 689 i Φ determined as per BS 1377
SW: dobro granulirani pijesak, GP: slabo granulirani šljunak, C-SP: grubi slabo granulirani pijesak, F-SP: sitni slabo granulirani pijesak emin određeno prema ASTM D 4253; emax određeno prema ASTM D 4254; gd(max) određeno prema ASTM D 689 i Φ određeno prema BS 1377,
This was attributed to the inclusion of different size of solid particles, which filled voids of the cement stabilized fibrous peat.
Razlog tome je što krute čestice različitih veličina popune praznine u cementom stabiliziranom vlaknastom tresetu.
Figure 5 also shows that coarse fillers decrease the shear strength of cement peat for up to 65 %.
Slika 5. pokazuje i da gruba punila smanjuju posmičnu čvrstoću cementnom stabiliziranog treseta i do 65 %.
Similar trends can be observed for specimens mixed with different filler dosages at 14, 28 and 90 days of curing.
Slično se može primijetiti i kod uzoraka miješanih s različitim udjelima punila nakon 14, 28 i 90 dana njege.
Different failure modes of stabilized peat are presented in Figure 6.
Slika 6. prikazuje različite oblike popuštanja stabiliziranog treseta.
Most of the specimens exhibit brittle failure while the undisturbed peat fails in a budging manner.
Većina uzoraka podložna je pucanju, a neporemećeni treset pomicanju.
Most cracks appear at an early stage at the top part of the specimen and propagate by stress increments until failure.
Većina pukotina nastala je u ranim fazama na vrhu uzorka i proširila se povećanjem naprezanja dok nije nastupilo konačno popuštanje.
As can be seen, specimens stabilized with cement fail by inclined crack only.
Uzorci stabilizirani cementom podložni su samo kosim pukotinama.
The same trend was observed in the cement peat mixed with SW, whereas vertical cracks appeared in most cement peat specimens mixed with F-SP.
Isto je karakteristično i za cementom stabilizirani treset miješan s dobro granuliranim pijeskom, a okomite pukotine svojstvene su cementom stabiliziranom tresetu miješanom sa sitnim slabo granuliranim pijeskom.
It should be mentioned that all stabilized specimens experienced small axial strain at failure which can be related to the brittle behavior of the specimens [17].
Napomenimo da su svi stabilizirani uzorci pri popuštanju bili izloženi malome osnom naprezanju, što je uzrokovalo krto popuštanje uzoraka [17].
Filler effect
Učinak punila
The influence of different natural fillers on cement stabilized peat has been analyzed.
U okviru istraživanja provedeno je i ispitivanje utjecaja različitih prirodnih punila na treset stabiliziran cementom.