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Analysis of the undrained shear strength through the standard Penetration

Test with Torque (Spt-T)

Article in International Journal of GEOMATE · January 2018

DOI: 10.21660/2018.41.81190

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International Journal of GEOMATE, Jan., 2018 Vol.14, Issue 41, pp.102-110
Geotec., Const. Mat. & Env., DOI: https://doi.org/10.21660/2018.41.81190
ISSN: 2186-2982 (Print), 2186-2990 (Online), Japan

ANALYSIS OF THE UNDRAINED SHEAR STRENGTH THROUGH

THE STANDARD PENETRATION TEST WITH TORQUE (SPT-T)
* J.C. Ruge1, C.C. Mendoza2, J.E. Colmenares3, R.P. Cunha4 and I.F. Otalvaro5
1
Facultad de Ingeniería. Programa de Ingeniería Civil Universidad Católica de Colombia. Bogotá, Colombia
2
Programa de Ingeniería Civil. Universidad Nacional de Colombia Sede Manizales, Colombia
3
Departamento de Ingeniería Civil y Agrícola. Universidad Nacional de Colombia, Bogotá D.C
4
Departamento de Engenharia Civil e Ambiental. Universidade de Brasília, Brasil
5
Departamento de Ingeniería Civil e Industrial. Pontificia Universidad Javeriana Cali, Colombia.

*Corresponding Author, Received: 17 Oct. 2017, Revised: 14 Nov. 2017, Accepted: 7 Dec. 2017

ABSTRACT: Although in situ tests are very useful for obtaining data on the strength and deformation of a
geomaterial, some of these tests have been criticized because of their limitations for identifying certain
parameters. This paper presents research into a hitherto little used test here in Colombia, the SPT-T (Standard
Penetration Test + Torque). This test combines the advantages of the Standard Penetration Test (SPT) and the
Vane Shear Test (VST) to obtain a soil’s lateral friction and to correlate its classification and structure by
means of the relationship between the NSPT and the torque applied. This study reaffirms the dependent
relation between T/NSPT and soil structure found elsewhere in the world and investigates whether parameters
governing the undrained condition of soil may be correlated with T/NSPT. Conceptually, a relationship
between undrained soil conditions and the way the test is conducted is evidenced. For this reason, this
research is an initial approach which open the door to continuing phases of research that may be able to
develop appropriate correlations between undrained strengths of soft soils and the T/NSPT parameter used in
analyses of this test.

Keywords: Undrained condition, SPT-T, in-situ tests, sedimentary soils, VST

1. INTRODUCTION obtained directly from the test. Testing

methodology based on ASTM D-1586-11 [1],
The standard penetration test with torque (SPT- NBR 6484/2001 [2] and INV E-111-13 [3] is
T) is a field test that combines SPT-type dynamic explained. The testing method involves removing
measurement methodology with static the head of the scaffolding, placing a centralizer
measurement of torque similar to the Vane Shear disc onto the guiding tube, fitting a torque wrench,
Test (VST). Both methodologies are still evolving. and measuring the torque for an indication of soil
Like the SPT, the SPT-T uses a split-spoon adherence to the sampler-soil.
sampler which is driven into the soil with a slide-
hammer. SPT-T can be used to measure two This test indicates soil behavior in terms of the
geotechnical factors, standard penetration lateral friction between the soil and the soil-
resistance and lateral friction (torque), rather than sampler and provides an important parameter for
just one factor. Unlike the SPT-T, the VST uses a deep foundation design that is both cheap and
probe with four orthogonal blades that is driven simple. Since SPT-T’s first use, researchers in
into the soil. Torque is then applied to the shaft various parts of the world have encouraged other
and measured. In the SPT-T, torque is applied to to use it in foundation engineering. Nevertheless,
the shaft of the split-spoon sampler and then specific studies about the use of this test are
measured. Test results can be used to derive T/NSPT needed to determine its real applicability to
(torque/number of blows) which can then be used geotechnical engineering.
to correlate soil classification and any soil
structure which may be present. 2. STATE-OF-THE-ART

This study is based on analysis of lateral Modernization of in-situ testing, first

friction of the soil-sampler in sedimentary soils of developed as a complement to laboratory tests, has
the region under study. Data was first obtained transformed it into a useful and versatile
through in-situ testing and then analyzed to alternative for obtaining geotechnical soil
demonstrate dependence between T/NSPT and some parameters. In-situ testing and laboratory testing
soil properties. Since appropriate overall each have drawbacks, but these can usually be
correlation for the current context would be balanced out by using both types of tests and
premature, this study is limited to a demonstration taking advantages of their reciprocal strengths. For
of the use of SPT-T analysis of parameters this reason, a subsoil study procedure should

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 International Journal of GEOMATE, Jan., 2018 Vol.14, Issue 41, pp.102-110

include a combination of the field and lab tests that In this manner, the lateral friction of the split-
are ideal for the problem to be addressed [4]. spoon sampler is obtained [9]. Figure 2 shows
The field tests most commonly used are SPT-T testing equipment: 1. Torque wrench, 2.
standard penetration tests, vane shear tests, cone Adapter, 3. Sampler extension bar, 4. Adjustment
penetration tests, penetrometers [5], disc, 5. Sleeve and 6. Rod.
pressuremeters and dilatometers. However, there is An advantage of this test is that the momentum
a wide variety of these tests currently in use in measured is not affected by as many variables as in
geotechnics. Each test tends to be designed for the the standard SPT. Factors that influence the
unique conditions of the soil type (Fig. 1) [6]. meaning of final SPT results, the number of
Most are not suitable for estimating geotechnical hammer blows required to drive the sampler,
parameters in all types of soil. Each test applies include potential errors in counting the number of
loads differently to measure soil response in order blows, drop height, weight of hammer, type of
to obtain physical characteristics of the material. sampler, and energy transfer from hammer blows.
Vertical drilling is required for SPT and some Through the addition of the torque wrench, the
versions of PMT and VST. Tests such as CPT and SPT-T also provides a reliable value of lateral
DMT do not require drilling since the direct-push friction. Several recent advances in the use of the
technique is used. This technique does not generate SPT-T for resolving geotechnical problems are due
shear within the soil to be tested. However, this to introduction of analysis of the correlation of
type of test is not recommended in hard materials T/NSPT (torque/number of blows) to various
such as cemented soils, rocks, and some gravels geotechnical parameters.
that may prevent free penetration. The first part of this study analyzes T/NSPT.
For this study, SPT-T has the advantage of The initial idea of using use torque measurement
combining the classic Standard Penetration Test with SPT was presented by Brazilian researchers
with the Vane Shear Test. SPT-T was created by [11]. They also proposed using the T/NSPT ratio as
Ranzini [7], [8] who proposed a slight alteration in a way to standardize NSPT apart from any additional
the SPT procedure based on the observation that geotechnical considerations related to
the operator applies torque to the bar with a hand classification of soils. These authors made various
tool at the end of the test. Ranzini thought that the measurements using several kinds of torque
wrench could simply be replaced with a torque to obtained with manual and electric equipment.
measure the maximum torque needed to overcome They concluded that measurements taken using
the sampler’s resistance to rotation. different means are satisfactory [9]. In addition,
The test basically uses the same principles as suggested the eq. 1 for the estimation of the lateral
the SPT [1]-[3] in the first step when the split- friction.
spoon sampler is inserted into the soil stratum
under study. In the second step, a torque wrench
attached to the bar, is used to rotate the sampler
while it measures the torsion required to overcome
the resistance of the soil.

Figure 1. in-situ tests [6]

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 International Journal of GEOMATE, Jan., 2018 Vol.14, Issue 41, pp.102-110

The SPT-T test do have the ability to provide

an independent assessment of the undrained shear
strength of the soil that is generated around the
sampler´s body by the measurement of the friction
stress mobilized on this region by torque
application. In other words, as previously
commented, the sampler´s shear resistance to
rotation. Likewise, the vane shear presents an
independent assessment of the undrained shear
strength of the soil by measuring a similar friction
Figure 2. Torque wrench and parts [10] stress that is mobilized on both lateral and
upper/down sides of a cylindrical element of soil
during torque application on the vane´s central bar
𝑓𝑇 = (2𝑇)⁄(𝜋𝑑 2 𝐿) (1) and blades.
It is possible to assume that both shear
Where T is the measurement of torque, d is the resistances might be similar in physical nature, and
diameter of the sampler, and L is the length of the therefore correlated somehow. This paper
sampler. advances on this thematic, showing trends between
This conclusion became important for the use derived SPT torque (expressed in terms of its
of torque measurement in engineering practice. division by number of blows, or T/NSPT) and the
[12] also analyzed how to obtain parameters for calculated undrained strength variable Su by the
the design of foundations from SPT-T based on the vane shear test. The comparison will also take on
results of a large-scale trial of the test that they consideration the undrained shear strength values
conducted. On the basis of these test, [12], measured on triaxial UU laboratory tests, as
presented some advantages, among others, SPT-T expressed on the final overall comparative table.
measures static T and dynamic N strength in a
single test. Another is that it provides 3. MATERIALS AND METHODS
standardization of the N value.
This section describes the project’s
2.1 Correlations for soil classification characteristics, materials and equipment. The soil
will be analyzed in detail on the basis of
[11] were the first to present correlations exploration conducted parallel to the testing with
between the torque obtained from SPT-T and N72 SPT-T.
in sedimentary soils (Eq. 2) and residual soils (Eq.
3). N72 is the N value for 72% driven efficiency 3.1 Study sites
which corresponds to the average energy required
with equipment used in Brazil. Driven efficiency is 3.1.1 Geological and geotechnical characteristics
defined as the energy required to drive the sampler
into the soil. According to the recommendation of The experimental field is located near the
[13], in Colombia it is possible to use 45%. foothills of the Andes on the savanna of Bogotá.
Its soil profile is typical of the region: the surface
𝑻 [𝒌𝒈 − 𝒇. 𝒎 ] = 𝟏. 𝟏𝟎 𝑵𝟕𝟐 (𝟐) layer is composed of anthropic fill, but is underlain
𝑻 [𝒌𝒈 − 𝒇. 𝒎 ] = 𝟏. 𝟖𝟒 𝑵𝟕𝟐 (𝟑) by clays and silts with some sand. Near the bottom
end of the boreholes (5.00 meters) gravel is also
For the authors, these correlations can reveal found. The soil is not strongly resistant to
problems found in the values of N in the SPT. This penetration with an SPT of between 4 and 9 blows,
is especially true when there are sandy layers has a low bearing capacity and a relatively high
containing gravels, a condition which requires content of water. The groundwater level surface is
more hammer blows to penetrate the sampler than found at 4.00 meters below the soil surface in
real value. [14] appreciated the great advantage of some places.
measuring the torque over the N value of SPT Table 1 lists parameters of the top few meters
since the first measurement is static while the of stratification at the study site. It can be seen
second measurement is dynamic. Another that there are clayey soils (CH and CL) suitable for
important advantage is that, even though during the SPT-T. In Table 1, w denotes the natural water
the SPT the soil structure breaks within the content, LL is the liquid limit and LP is the plastic
sampler, the torque measures the lateral friction in limit. Additional boreholes were drilled at another
the region, which, despite the invasion by the site in the south of the city, in order to analyze
sampler, still preserves its original structure. For other types of soft soil with this methodology.
this reason, structured soils tend to have higher
T/NSPT (details in [15]).

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Table 1. Basic characterization parameters The SPT-T test do however have some major
LL LP limitations, as those clearly provided by [9] in her
Sample Depth (m) w (%) USC
(%) (%) PhD Thesis. It lacks standardization and its final
First site
results are clearly influenced by the type of
S2M1 1.00 – 1.50 37.4 50.6 21.6 CH
S2M2 1.50 – 2.00 32.8 67.9 29.4 CH equipment, operating crew, level of energy &
S2M3 2.00 –2.50 32.1 48.1 24.5 CL associated losses, type of driving hammer and the
S2M4 2.50 – 3.00 34.1 45.7 23.0 CL overall physical conditions of the sampler unit.
S2M5 3.00 – 3.50 29.4 25.6 15.7 CL Nevertheless, it is still the most used equipment in
S3M1 1.10 – 1.18 36.3 65.8 31.6 CH
S3M2 2.40 – 2.90 21.9 58.0 24.9 CH
South America for field works, geotechnical
S4M1 1.30 – 1.90 31.7 58.1 32.8 MH characterization and foundation design. Hence, its
S4M2 2.30 – 2.90 55.2 69.7 34.5 MH usage is justified in the present study, although it is
S4M3 3.20 – 3.80 31.5 40.6 22.1 CL recognizable that other better techniques to derive
S5M1 1.40 – 1.90 31.4 53.8 25.7 CH the undrained shear strength are available (see
S5M2 1.90 – 2.40 34.0 48.2 23.0 CL
S5M3 2.40 – 2.90 45.4 59.8 26.9 CH [24]).
S5M4 2.90 – 3.40 40.1 48.9 22.1 CL
S5M5 3.40 – 3.90 30.4 30.7 19.2 CL 3.3 VST Test (Vane Shear Test)
S8M1 1.50 – 2.00 26.7 37.7 21.7 CL
Second site For this type of study, it is necessary to have
S2M1 1.60 – 2.20 66.45 110.0 46.0 MH data in order to calibrate the new test to be
S2M2 2.50 – 3.10 72.89 116.0 61.0 MH evaluated. It was decided to conduct the VSTs
S2M3 3.40 – 4.00 26.40 39.0 18.0 CL
S2M4 4.40 – 5.00 25.42 26.0 14.0 CL during the exploration campaign. We decided to
follow the guidelines of the [16] and use
3.2 SPT-T (Standard Penetration Test+Torque) rectangular and trapezoid vanes to determine
undrained shear strength (Su). Even though the
Testing in the experimental field began with T/N value of SPT-T has not yet has been directly
the standard penetration test which was conducted correlated with Su. This means that these
according to [1], [3]. A donut hammer was used measurements can be important for analysis of the
which allowed an approximate efficiency of 45% results of this research even though undrained
given the configuration used during all testing and resistance depends on other factors such as
the Colombian context for this test [13]. For this anisotropy, OCR and stress paths.
study, the NSPT parameter was obtained using
methodologies from [13] for correcting the 3.4 Laboratory test
parameter according to confining and energy. N145
As mentioned, the best accepted correlations
was obtained when the blows delivered in the field
for the SPT-T are related to soil-sampler adherence
were corrected.
estimation from which the soil can be classified
and in some cases the soil structure characterized.
Subsequently, we applied torque to the
This is the focus of this study: to use T/N for a first
extension bar of the split-spoon sampler that had
approach, within the framework described, both in
been driven into the ground in the first part of the
soil classification and characterization,
test. Torque was applied through constant 360°
emphasizing in the undrained condition of the soil.
rotation which will be called Tmax in this article.
In addition to VST, for characterization of the
After 30 seconds, residual torque was measured.
soil in terms of its shear strength a series of tests
This new measurement has been named Tres (Fig.
was performed. Under in-situ conditions, it is
3).
evident that when there are undrained conditions it
will affect the vicinity of the split-spoon sampler
because of the speed of execution. For this reason,
we decided to perform UU triaxial tests that were
consistent with an exposed scenario, related with
the obtaining of undrained parameters and the
articulation with soil-sampler adherence since this
may have an essential connection to the response
of undrained soil.

4. RESULTS

4.1 SPT-T

Figure 3. Torque wrench used in the SPT-T. Eight boreholes of four to five meters in depth
were drilled to obtain a stratigraphic profile as

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 International Journal of GEOMATE, Jan., 2018 Vol.14, Issue 41, pp.102-110

described previously. In three boreholes SPT-Ts 8 (SPT–T) 8+8 60 52.5 0.52

were conducted. VSTs were performed with 9 (VSTt) ― 80 20 ―
rectangular vane (VRTr) and trapezoidal vane 2 (SPT–T) 6+5 80 55 1.01
(VSTt) in the remaining boreholes. 3 (VSTt) ― 50 20 ―
2.50 4 (VSTt) ― 70 30 ―
Table 2 shows the SPT-T results. The first part
– 5 (SPT–T) 3+3 60 52.5 1.39
of the test was based on SPT in accordance with 3.00 7 (VSTt) ― 45 22.5 6.23
[1], [3], and the torque was applied on the basis of 8 (SPT–T) 10+6 77.5 45 0.67
the Brazilian experience with this type of test [9]. 9 (VSTt) ― 80 20 ―
T/NSPT was carefully observed. According to the 2 (SPT–T) 1+1 47.5 40 3.29
literature found, T/NSPT is the most key factor for 3 (VSTt) ― 50 22.5 ―
correlating the lateral friction and load capacity of 3.00 4 (VSTt) ― 45 15 ―
piles. It is also important for soil classification – 5 (SPT–T) 1+3 67.5 65 1.34
purposes as in this article [14]. In accordance with 3.50 7 (VSTt) ― 20 10 2.77
[11] who correlated torque and N172 (Eq.1, 2) in 8 (SPT–T) 1+1 55 47 3.81
9 (VSTt) ― 80 30 ―
sedimentary and residual soils in Brazil, it was
2 (SPT–T) 1+1 30 27.5 2.08
observed that at three meters of depth an adequate 3.50
4 (VSTt) ― 30 10 ―
correlation exists between the number of blows –
5 (SPT–T) 3+2 67.5 50 1.87
and the torque applied [17]. For Colombia, the 4.00
7 (VSTt) ― 20 10 2.77
correlation was made with N145, according to the 2 (SPT–T) 1+1 0 0 ―
recommendation of [11], [13]. 4.00
3 (VSTt) ― 25 5 ―
–
From results obtained in field, it was observed 4 (VSTt) ― 30 10 ―
4.50
that from 3.00 meters deep, the dispersion between 7 (VSTt) ― 45 25 1.25
the two parameters is high due to the presence of Second Site
fine gravels. Even though the number of hammer 1.60 1 (VSTt) ― 70 15 ―
blows do not increase the number, friction between –
2.20 2 (SPT–T) 2+2 65 40 2.25
soil and the sampler increases as indicated by
measuring torque. The T/NSPT ratio is useful 2.50 1 (VSTt) ― 100 37.5 ―
–
because it combines the measurement of a static 3.10 2 3+3 75 50 1.73
parameter (T) and a dynamic one (N). In addition, 3.40 1 (VSTt) ― 45 25 ―
the measurement of torque indicates lateral friction –
in around the sampler within the soil that has been 4.00 2 1+2 57.5 35 2.65
only partially altered and still retains its original 4.40 1 (VSTt) ― ― ― ―
structure. According to this, structured soils tend to –
5.00 2 2+3 60 30 1.66
have greater T/NSPT, but the current results reveal
that the tested soils are poorly structured,
Numerous studies [7], [8], [9], [11], [12], [14],
consistent with what is mentioned by [14].
[15] have shown that the results of SPT-T are
useful for soil classification and analysis of soil
Table 2. Number of blows in field, maximum and
residual torque in VST and SPT-T. structure.
Depth Tmax Tres T/N [kg-
(m)
Borehole NF
[lbf-ft] [lbf-ft] f/m]
4.2 Unconsolidated Undrained Triaxial Tests
First Site
Nevertheless, it is reasonable to think that the
1 (VSTr) ― 75 25 ―
undrained soil conditions are related to responses
2 (SPT–T) 4+6 115 85 1.59
1.00
3 (VSTt) ― 60 25 ―
to the soil sampler tests since torque is applied
– suddenly in soft soil. For this reason, it should
4 (VSTt) ― 60 25 ―
1.50
5 (SPT–T) ― 65 20 ― eventually be possible to relate torque
8 (SPT–T) ― 80 30 ― measurements, and even the T/NSPT value, to an
1 (VSTr) ― 80 20 ― undrained parameter obtained from tests of soils
2 (SPT–T) 4+5 70 65 1.07 with this drainage characteristic. Table 3 shows the
3 (VSTt) ― 60 20 ―
1.50 results of UU triaxial tests.
4 (VSTt) ― 60 27.5 ―
–
5 (SPT–T) 3+4 82.5 60 1.63
2.00 4.3 Comparison of results from SPT-T, VST
7 (VSTt) ― 20 5 ―
8 (SPT–T) 5+5 97.5 90 1.35 and TUU laboratory tests
9 (VSTt) ― 55 20 ―
1 (VSTr) ― 57.5 30 ― This analysis is oriented toward evaluating SPT-
2.00 2 (SPT–T) 5+6 70 65 0.88 T’s usefulness for classifying soils and identifying
– 3 (VSTt) ― 72.5 30 ― soil structures. Within this study, T/NSPT
2.50 4 (VSTt) ― 80 25 ―
determines the incidence of these two parameters.
5 (SPT–T) 3+4 85 70 1.68

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The values of T/NSPT in the first case study do not the soil far more than does application of torque to
reveal any trend related to depth. Instead, they a spoon sampler. Even though it also produces
fluctuate, mostly between 1 and 2. According to some failure of the material, due to the
[14], this type of result implies that these soils are characteristics of this type of probe the lateral area
derived from sedimentary deposits. These soils of the sampler tends to slide more smoothly
close to the eastern piedmont of the city are through the soil, especially in soft soils. The T/NSPT
formed from deposits that have been weathered parameter, as at the first study site, shows that soils
over time from the rocks of the eastern hills and are poorly structured and tend to be sedimentary.
then transported by rivers of the savanna. Over This is consistent with the deposits found at this
time they have formed deeper layers of sediment. location. This study validates, in principle, that the
For this reason, the value of T/NSPT should, in variable T/NSPT is compatible with the soil
principle, be close to that based on global structure using the Brazilian experience as a
experience in this type of characterization. reference point.
A comparison of the Su corrected by VST with
Table 3. TUU Tests for σ3 of 100, 200, 400 the value obtained in UU triaxial testing shows
(kN/m2) that the field test tends to produce a more
Sample Depth (m) Su (𝐤𝐍/𝐦𝟐 ) conservative value than that obtained in the
First site laboratory which makes the field test more suitable
S2M1 1.00 – 1.50 135
S2M2 1.50 – 2.00 101
for any analysis. For the purpose of this research, it
S2M3 2.00 –2.50 109 is important to clarify that, although there are
S2M4 2.50 – 3.00 89 established precedents for a possible correlation
S2M5 3.00 – 3.50 71 between T/N and undrained soil conditions, a
S5M1 1.40 – 1.90 111 general study is needed to obtain better correlation.
S5M2 1.90 – 2.40 97
S5M3 2.40 – 2.90 105
This is important because rotation of the split-
S5M4 2.90 – 3.40 90 spoon sampler eventually generates undrained soil
S5M5 3.40 – 3.90 75 conditions at the time of application of the test [19].
Second site This research presents a high level of
S2M1 1.60 – 2.20 178 coincidence with previous studies which indicates
S2M2 2.50 – 3.10 123 that SPT-T is not only novel, but is a promising in-
S2M3 3.40 – 4.00 93
situ test. In fact, it is currently coming into use by
S2M4 4.40 – 5.00 64
consulting firms around the world. Also, is
The methodology of [14] also suggests that revealed a solid correlation exists between the
smaller values of T/NSPT imply less structured soil. dynamic measurement NSPT and static
measurements. For details see [20]-[22]. Although
This coincides with the soil analyzed in this study
there is congruence in the simplicity of the analysis
which has no structure. VST and UU triaxial
and execution of the test in this study, according to
results were correlated with SPT-T results for
[23] this methodology is incapable of providing
undrained soil conditions. Table 4 shows the results that can lead to fully established
undrained resistance of the soil analyzed at the first correlations. This is due to several factors, among
and second study site obtained from two different which is the fact that the ranges of torque found in
pathways. Suλ is estimated from the VST and diverse types of soil overlap which can generate
corrected with the proposal of [18] that uses the PI ambiguous results. Similarly, the Brazilian
as correction parameter. SuUU is the undrained experience provides valid data for specific sites but
resistance determined by unconsolidated undrained these data cannot be extrapolated to any soil
triaxial. classification [24],[25].
Compatibility of torques measured using
different probes can be found by comparing 5. CONCLUSIONS
maximum torque and residual torque. In all cases,
the materials were found to have sensitivities The standard penetration test with torque
(Tmax/Tres) of close to two or three times. However, definitively complements conventional research
conducted with SPT, and, moreover, it provides a
it is logical to think that the structure of a soil
higher technical level. It overcomes many of the
tested with a vane probe will suffer greater
technical limitations for which SPT has been
distortion than the structure of a soil tested with a
strongly criticized, and is emerging as a more
split-spoon sampler, and this matches the results reliable field test. The combinations of SPT, VST,
obtained. and SPT-T or additional tests reduces uncertainty
When torque is applied to the vane probe, the by correctly characterizing a site [26],[27],[28].
movement of the vanes accentuates rupturing of

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Table 4. Number of blows in the field, maximum / residual torque in VST, SPT-T, 𝑆𝑢𝜆 and. 𝑆𝑢𝑈𝑈
Tmax [lbf-
Depth (m) Borehole NF Tres [lbf-ft] 𝑆𝑢𝜆 [𝑘𝑁/𝑚 2 ] T/N [kg-f/m] SuUU [kN/𝑚2]
ft]
First Site
1 (VSTr) ― 75 25 196.88 ― ―
2 (SPT–T) 4+6 115 85 ― 1.59 135
3 (VSTt) ― 60 25 152.25 ― ―
1.00 – 1.50
4 (VSTt) ― 60 25 164.5 ― ―
5 (SPT–T) ― 65 20 ― ― ―
8 (SPT–T) ― 80 30 ― ― ―
1 (VSTr) ― 80 20 196.0 ― ―
2 (SPT–T) 4+5 70 65 ― 1.07 101
3 (VSTt) ― 60 20 152.25 ― ―
4 (VSTt) ― 60 27.5 164.5 ― ―
1.50 – 2.00
5 (SPT–T) 3+4 82.5 60 ― 1.63 111
7 (VSTt) 1+1 20 5 61.25 ― ―
8 (SPT–T) 5+5 97.5 90 ― 1.35 ―
9 (VSTt) ― 55 20 168.43 ― ―
1 (VSTr) ― 57.5 30 161.0 ― ―
2 (SPT–T) 5+6 70 65 ― 0.88 109
3 (VSTt) ― 72.5 30 186.08 ― ―
2.00 – 2.50 4 (VSTt) ― 80 25 210.0 ― ―
5 (SPT–T) 3+4 85 70 ― 1.68 97
8 (SPT–T) 8+8 60 52.5 ― 0.52 ―
9 (VSTt) ― 80 20 219.33 ― ―
2 (SPT–T) 6+5 80 55 ― 1.01 89
3 (VSTt) ― 50 20 128.33 ― ―
4 (VSTt) ― 70 30 177.63 ― ―
2.50 – 3.00 5 (SPT–T) 3+3 60 52.5 ― 1.39 105
7 (VSTt) ― 45 22.5 118.13 ― ―
8 (SPT–T) 10+6 77.5 45 ― 0.67 ―
9 (VSTt) ― 80 20 210.0 ― ―
2 (SPT–T) 1+1 47.5 40 ― 3.29 71
3 (VSTt) ― 50 22.5 131.25 ― ―
4 (VSTt) ― 45 15 133.87 ― ―
3.00 – 3.50 5 (SPT–T) 1+3 67.5 65 ― 1.34 90
7 (VSTt) ― 20 10 52.5 ― ―
8 (SPT–T) 1+1 55 47 ― 3.81 ―
9 (VSTt) ― 80 30 210.0 ― ―
2 (SPT–T) 1+1 30 27.5 ― 2.08 ―
4 (VSTt) ― 30 10 89.25 ― ―
3.50 – 4.00
5 (SPT–T) 3+2 67.5 50 ― 1.87 75
7 (VSTt) ― 20 10 52.5 ― ―
2 (SPT–T) 1+1 0 0 ― ― ―
3 (VSTt) ― 25 5 65.63 ― ―
4.00 – 4.50
4 (VSTt) ― 30 10 78.75 ― ―
7 (VSTt) ― 45 25 118.13 ― ―
Second Site
1 (VSTt) ---- 70 15 149.04 ---- ----
1.60 – 2.20
2 (SPT–T) 2+2 65 40 ---- 2.25 178
1 (VSTt) ---- 100 37.5 221.66 ---- ----
2.50 – 3.10
2 (SPT–T) 3+3 75 50 ---- 1.73 123
1 (VSTt) ---- 45 25 130.94 ---- ----
3.40 – 4.00
2 (SPT–T) 1+2 57.5 35 ---- 2.65 93
1 (VSTt) ---- ---- ---- ---- ---- ----
4.40 – 5.00
2 (SPT–T) 2+3 60 30 ---- 1.66 64

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[28] Hafez, D., Mahgoub, A., and Kief, M. General
including the making of copies unless permission is
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obtained from the copyright proprietors.
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GEOMATE, Jan., 2017, Vol. 12, 29, pp. 132 -
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