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International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 613
ISSN 2229-5518
IJSER © 2019
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Predicting (Nk) factor of (CPT) test using (GP):
Comparative Study of MEPX & GN7
Ahmed H. ELbosraty1
, Ahmed M. Ebid2
, Ayman L. Fayed3
Abstract— Static cone penetration test (CPT) is a broadly satisfactory and dependable geotechnical in-situ apparatus that gives brisk and
honest substantial measure of data about soil classification, stratification and properties. Un-drained shear strength of clay (cu) is one of
the principle soil parameters that could be sensibly evaluated from the (CPT) results, as it is specifically connected to the tip resistance
through the experimental cone factor (Nk). Earlier researches showed that (Nk) value depends on type of soil, nature and stress history
conditions and many other variables. Construction development in some locations with thick deposits of soft to very soft clays motivates
extensive researches to define the reasonable value of the (Nk) factor for such types of clay. The performed study concentrated on utilizing
the genetic programming technique (GP) to predict (Nk) value of clay using the consistency limits that can be easily determined in the
laboratory. A set of 102 records were gathered from the CPT site investigations and corresponding consistency limits and other physical
properties experiments, were divided into training set of 72 records and validation set of 30 records. Both (GN7) & (MEPX) software were
used to apply (GP) on the available data. Four trials for each software with different chromosome lengths were performed to correlate the
(Nk) factor with the clay consistency limits, water content (wc) and unit weight (γ) using training data set, then, the produced relations were
tested using the validation data set. The four generated formulas using (GN7) showed accuracies ranging between 93% and 97% and
coefficient of determination (R2
) ranging between 0.7 and 0.9, while the other four formulas form (MEPX) showed accuracy not exceeding
95% and coefficient of determination (R2
) ranging between 0.45 and 0.75.
Index Terms— CPT, Consistency Limits, Genetic Programming (GP), Multi Expression Programming (MEP), Cone Factor (Nk).
——————————  ——————————
1 INTRODUCTION
Lassic static cone penetration test (CPT) is one of the well-
known site tests which carried out to characterize the soil
formations and estimate their mechanical proprieties
based on their penetration resistance. Today, modern (CPT)
equipment is capable to measure many more parameters than
penetration resistance such as pore water pressure, lateral soil
pressure at rest, lateral elastic modulus of soil. Figure (1)
shows (CPT) test overview and sample of its output. [3, 10,
15].
Many theories were introduced to simulate the behavior of the
soil during static penetration process such as the bearing ca-
pacity theory (Meyerhof 1961, Durgunoglu and Mitchell 1975),
cavity expansion theory (Vesic 1972 and Yu and Houlsby
1991), the strain path method proposed by Baligh (1985), cali-
bration chamber testing and the finite element analysis (Walk-
er and Yu 2006). [1, 8, 9, 12, 17,19 and 20].
Although, many previous researches were carried out to corre-
late tip resistance from (CPT) with other soil properties spe-
cially the un-drained shear strength of clay (cu), but none of
them derives a proper correlation due to the sophisticated be-
havior of the clay which depends on many parameters such as
initial stresses, pore-water pressure, penetration rate and over
consolidation ratio. In addition, uncertainties in measured
values make the correlation more difficult. [4, 14].
Previously suggested formulas to correlate (CPT) results with
the un-drained shear strength of clay (cu) are summarized in
many publications [3, 6, 9, 10, 15, and 16]. Many of those re-
searches considered that (cu) proportional linearly with the
corrected tip resistance of the cone as shown in equation (1)
Nk
q voc
u
σ−
=c ….... (1)
Where,
cu : Un-drained shear strength of clay.
qc : Tip resistance of the cone.
σvo : Total overburden pressure.
Nk : Empirical cone factor.
Accordingly, most of the previous researches were concerned
in estimating (Nk) value which correlates (CPT) with (cu).
As summarized by Zsolt Rémai (2013) [17], typical values for
(Nk) for different soil types has been suggested by many re-
searchers. Lunne and Kleven (1981) [13] suggested that (Nk)
varies between 11 and 19 for normally consolidated, Scandi-
navian marine clays. Jörss (1998) [7] suggested that (Nk)
equals 20 for marine clays and 15 for boulder clays. Gebre-
selassie (2003) [5] proposed that (NK) value is ranged between
7.6 and 28.4 for different soil types. Finally, Chen (2001) [4]
recommended (Nk) values varying between 5 and 12.
C
————————————————
1 Graduate Student, Department of Structural Engineering, Faculty of Engi-
neering, Ain Shams University E-Mail: eng_elbosraty@yahoo.com
2 Lecturer, Department of Structural Engineering, Faculty of Engineering &
Tech.., Future University, Egypt. E-Mail: ahmed.abdelkhaleq@fue.edu.eg
3 Associate Professor, Department of Structural Engineering, Faculty of
Engineering, Ain Shams University E-Mail: ayman_fayed@eng.asu.edu.eg
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(a)
(b)
Figure (1) Cone Penetration Test (CPT): a) Test Overview, b) Output Example
(after Paul W. Mayne and Jon M. Williams (2007))
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2 (GP) & (MEP)
2.1 Genetic programming (GP)
(GP) is a direct application of genetic algorithm (GA) optimi-
zation technique on a population of mathematical formulas to
generate the most fitting formula for certain given points in a
hyper-space. Accordingly, (GP) may be described as Multivar-
iable Regression Procedure. (Koza,1994)
(GP) is big title includes several techniques such as Linear GP,
Cartesian GP, Compacted GP and many others. [2 ,11,18].
Classic (GP) procedure starts with randomly generating a
population of mathematical formulas which are encoded in
genetic form (chromosome form) and testing each formula
using the training data set to calculate its fitness. Only the
most fitting formulas (survivors) will be selected to generate
the next cycle (or generation) using crossover and mutation
operators, then the new population to be tested again to calcu-
late their fitness and so on until accepted accuracy is achieved.
2.2 Multi Expression Programming (MEP)
(MEP) is a technique to automatic generation of computer
programs. Accordingly, it could be used to generate fitting
mathematical formulas for certain data set. MEP differentiates
from classic (GP) techniques by encoding multiple solutions in
the same chromosome. Same as classic (GP), crossover is ap-
plied in (MEP) using one Point Crossover technique, where
one crossover point is randomly chosen and the parent chro-
mosomes exchange the sequences at the right side of the
crossover point. Also, both classic (GP) and (MEP) are sharing
the same mutation technique where randomly selected gens
(or symbols) are changed. Unlike classic (GP), the output of
the (MEP) is a series of programming commands, if all these
commands are mathematical expressions, then the output
could be simplified in one mathematical expression just like
classical (GP).
3 (GN7) & (MEPX)
3.1 (GN7) software
(GN7) is the 7th version of classic (GP) software which was
developed by the author in (2004) in C++[2]. Figure (2) shows
the encoding technique and the principal of tree levels to
measure the complexity of the mathematical formula. It is
clear that complex of the formulas needs more levels to repre-
sent it than simple ones. As shown in Figure (2). The chromo-
some consists of two parts, “operators” and “variables”. The
“operators” part contains the entire tree except the level 0 and
has (2No. of levels - 1) genes. The “variables” part contains only the
level 0 of the tree and has (2No of levels) genes. Therefore, the total
number of genes in the chromosome is (2No. of levels + 1) genes [2].
(GN7) supports eight operators which are (=, +, -, x, /,Xy , e^,
Ln) and support up to 7 levels of complexity. Regarding
crossover procedure, it doesn’t support the classic one-point
crossover technique, instated, it supports random crossover
technique which was proposed by author, 2004 [2] to generate
the new chromosomes by randomly selecting each gene from
similar surviving chromosomes as shown from figure (3). Mu-
tation is applied by replacing some randomly selected genes
with random operator (in the “operators” part) or variable (in
“variables” part). Since most mathematical formula have con-
stant values, hence variables with constant values are used to
present those constants. Usually, the following set of constants
is used (1, 3, 5, 7 and 11). (GN7) uses the sum of squared errors
(SSR) method to measure the fitness.
Figure (2) Mathematical and Genetic Representation of Binary
Tree (after A. Ebid 2004)
Figure (3) Random Crossover Technique (after A. Ebid 2004)
3.2 (MEPX) software
(MEPX) is free and open source software that uses (MEP)
technique. This project started in 2001 and the first end-user
for windows is released in 2015. Unlike (GN7), current version
of (MEPX) has a graphical user interface (GUI). Both source
code and compiled software could be freely downloaded from
http://www.mepx.org. The software is easy to learn and of-
fers many options to control the searching process as shown in
figure (4), these options could be summarized in the following
points:
- Three types of problems (regression, binary classifica-
tion and multi-class classification)
- Two methods to measure error (mean absolute error
and mean squared error)
- 26 different mathematical, logical, statistical and trig-
onometrical operators.
- Two methods of crossover (uniform and one point
crossover)
- Two methods to generate constants (user defined and
automatically generated)
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- Code length, is the number of genes on each chromo-
some, it is a measurement for the complexity of the
solution which is equivalent to number of levels in
(GN7).
Figure (4) screenshot of (GUI) of (MEPX) software
3.3 Comparison Bases
In order to fairly compare the results of the two programs, the
following points were considered:
- Using same set of variables, liquid limit (L.L), plastic
limit (P.L), plasticity index (P.I), water content (wc)
and unit weight of clay (γ).
- Using same constant values (1,3,5,7,11)
- Using the same training and validation data sets
- Using the same population size
- Using same number of generations
- Using same method to measure error (SSR)
- Using same complexity level (code length)
- Since the output should be mathematical formula, on-
ly mathematical operators were used in (MEPX)
- Unaccepted too complicated expressions such as mul-
ti-power (x^(y^z)) and multi logarithms (log(log(x))
were eliminated from both programs.
- For the best fitting formula of each trial, its accuracy
was determine using equation (2) , the predicted val-
ues of (Nk) were plotted against the experimental
ones and the coefficient of determination (R2) was de-
termined.
rec
cal
NNk
NkNk 100
100=(%)Accuracy
exp
exp
×
−
− ∑ …(2)
4 PREDICTION OF (NK) USING (GN7)
Four trials were carried out using (GN7) to predict the value
of (Nk) factor using the training data set as follows:
- 1st trial had only two levels of complexity (chromo-
some length is 8 genes), Population size was 5000
chromosome, number of generations was 50 and the
best formula was equation (3)
LP
LL
.
.6.3
7.32=Nk
×
− …(3)
- 2nd trial had three levels of complexity (chromosome
length is 16 genes), Population size was 10000 chro-
mosome, number of generations was 50 and the best
formula was equation (4)
56.2
.
.12
)-(PILn.161=Nk −





×
LL
LP
γ …(4)
- 3rd trial had four levels of complexity (chromosome
length is 32 genes), Population size was 20000 chro-
mosome, number of generations was 50 and the best
formula was equation (5)
79.1
.).(
20
.
.21
.111=Nk
2
−








+
+
×
LPLnLL
LP
…(5)
- 4th trial had five levels of complexity (chromosome
length is 64 genes), Population size was 40000 chro-
mosome, number of generations was 50 and the best
formula was equation (6)
19.5)5).()(2(
)14.04(
3)/5(.
.31=Nk −





−−−
+
++
× LLLnPILn
PILn
LP
γ
γ
…(6)
Accuracies and coefficient of determination (R2) of training
and validations sets for each one of the four trials are summa-
rized in table (1). Figure (5) represent the correlation between
the predicted (Nk) values using the equations (3),(4),(5),(6)
and the measured ones.
TABLE (1): SUMMARY OF ACCURACIES AND (R2
) VALUES FOR
EQUATIONS (3),(4),(5),(6)
TrialNo.
No.ofLevels
Proposed
Formula
Accuracy % R2
Training
Validation
Total
Training
Validation
Total
1 2 Eq. (3) 93 95 94 0.72 0.71 0.71
2 3 Eq. (4) 96 97 96 0.87 0.89 0.87
3 4 Eq. (5) 96 96 96 0.82 0.88 0.84
4 5 Eq. (6) 96 97 97 0.91 0.88 0.87
The following points could be noted from table (1):
- Accuracies of all proposed formulas are ranged be-
tween 93% to 97%, while (R2
) values are ranged be-
tween 0.71 to 0.91 which indicates good fitting
- The enhancement in fitting between equations
(4),(5),(6) is negligible, on other hand, the remarkable
complexity difference between them makes equation
(4) more favorable than the others.
- None of the four proposed formulas contains water con-
tent (wc) which indicates that (Nk) doesn’t depend on
it.
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a) Trial(1) – Eq. 3 b) Trial(2) – Eq. 4
c) Trial(3) – Eq. 5 d) Trial(4) – Eq. 6
Figure (5) Relation between the Predicted and Measured (Nk) values for Developed Correlations using (GN7)
5 PREDICTION OF (NK) USING (MEPX)
Four equivalent trials were carried out using (MEPX) to pre-
dict the value of (Nk) factor using the training data set as fol-
lows:
- 1st trial had chromosome length of 8 genes, Popula-
tion size was 5000 chromosome, number of genera-
tions was 50 and the best formula was equation (7)
IP
LL
.
55.11
=Nk
−
…(7)
- 2nd trial had chromosome length is 16 genes, Popula-
tion size was 10000 chromosome, number of genera-
tions was 50 and the best formula was equation (8)
[ ](P.I)LnP.IP.L11
.11
11
=Nk +++
+ IP
…(8)
- 3rd trial had chromosome length is 32 genes, Popula-
tion size was 20000 chromosome, number of genera-
tions was 50 and the best formula was equation (9)
( )( )[ ]).ln(7).(6.1
.
7
)./7(
./7
=Nk IPIPLn
IPIPLn
IP
−+++ …(9)
- 4th trial had chromosome length is 64 genes, Popula-
tion size was 40000 chromosome, number of genera-
tions was 50 and the best formula was equation (10)
11.
)5(
P.I
)5(11L.L11
=Nk 2
−
+
+
IP
Ln
γ
γ
…(10)
Accuracies and coefficient of determination (R2) of training
and validations sets for each one of the four trials are summa-
rized in table (2). Figure (6) represent the correlation between
the predicted (Nk) values using the equations (7),(8),(9),(10)
and the measured ones.
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a) Trial(1) – Eq. 7 b) Trial(2) – Eq. 8
c) Trial(3) – Eq. 9 d) Trial(4) – Eq. 10
Figure (6) Relation between the Predicted and Measured (Nk) values for Developed Correlations using (MEPX)
TABLE (2): SUMMARY OF ACCURACIES AND (R2
) VALUES FOR
EQUATIONS (7),(8),(9),(10)
TrialNo.
CodeLength
Proposed
Formula
Accuracy % R2
Training
Validation
Total
Training
Validation
Total
1 8 Eq. (7) 93 93 93 0.44 0.54 0.52
2 16 Eq. (8) 94 94 94 0.53 0.63 0.58
3 32 Eq. (9) 93 94 94 0.53 0.58 0.56
4 64 Eq. (10) 95 95 95 0.63 0.76 0.67
The following points could be noted from table (2):
- Accuracies of all proposed formulas are ranged be-
tween 93% to 95%, while (R2
) values are ranged be-
tween 0.44 to 0.76 which indicates fair fitting
- Equation (10) is the most accurate one and the only one
that used unit weight (γ) variable which indicates the
importance and the impact of this variable.
- None of the four proposed formulas contains water con-
tent (wc) which indicates that (Nk) doesn’t depend on
it.
6 CCONCLUSIONS
By comparing the summarized results in tables (1),(2), the fol-
lowing points could be noted:
- Although equation (4) is not the most accurate pro-
posed formula, but considering its simplicity, it is still
the most favorable one.
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- Formulas contains unit weight (γ) variable are more ac-
curate than others regardless the used software, this re-
flects the high correlations between (Nk) and (γ).
- None of the proposed formulas regardless the used
software contains water content (wc) which indicates
that (Nk) doesn’t depend on it.
- Although proposed formulas from (GN7) & (MEPX)
almost have same accuracies for same level of com-
plexity (code length), but coefficients of determination
(R2) of (GN7) formulas are higher than those of
(MEPX) which indicates the random crossover tech-
nique of (GN7) is more efficient than the one point
crossover technique of (MEPX).
- It is also noted that (MEPX) is almost twice faster
than (GN7), this may be because (MEPX) uses multi
threads.
REFERENCES
[1] Aas, Gunnar, Suzanne Lacasse, Tom Lunne, and Kaare Hoeg. "Use of
in situ tests for foundation design on clay." In Use of In Situ Tests in
Geotechnical Engineering, pp. 1-30. ASCE, (1986).
[2] Ahmed M. Ebid, Ezzat A. Fattah, Hossam E.A. Ali. "Applications of
genetic programming in geotechnical engineering. " DOI:
10.13140/RG.2.1.1967.9203 (2004).
[3] Boufrina, T., Bouafia, A., Panfilov, A. V., & Ter-Sarkisova, L. A.
"Numerical modeling of CPT in clay to evaluate bearing capacity for
shallow foundations." Проблемы и перспективы развития
сельского хозяйства и сельских территорий. (2014).
[4] Chen, C. "Evaluating un-drained shear strength of Klang clay from
Cone penetration test." In International Conference on In situ Meas-
urement of Soil Properties and Case Histories, In: Proceedings of the
International Conference on In Situ Measurement of Soil Properties
and Case Histories, Graduate Program, Parahyangan Catholic Uni-
versity, pp. 141-148. (2001).
[5] Gebreselassie, Berhane. "Experimental, Analytical and Numerical
Investigations of Excavations in Normally Consolidated Soft Soils."
(2003).
[6] Hossain, Md Imran. "Evaluation of Un-drained Shear Strength and
Soil Classification from Cone Penetration Test." (2018).
[7] Jörß, O. "Erfahrungen bei der Ermittlung von cu-Werten mit der
Hilfe von Drucksondierungen in bindigen Böden." Geotechnik 21,
no. 1 (1998): 26-27.
[8] Kim, Daehyeon, Younjin Shin, and Nayyar Siddiki. "Geotechnical
design based on CPT and PMT." (2010).
[9] Kim, Hobi, Monica Prezzi, and Rodrigo Salgado. "Use of dynamic
cone penetration and clegg hammer tests for quality control of road-
way compaction and construction." (2010).
[10] Kim, Kwang Kyun, Monica Prezzi, and Rodrigo Salgado. "Interpreta-
tion of cone penetration tests in cohesive soils." (2006).
[11] Koza, John R. Genetic programming II, automatic discovery of reus-
able subprograms. MIT Press. Cambridge, MA, (1992).
[12] Larsson, R., and M. Mulabdic. Piezocone tests in clay. Swedish Ge-
otechnical Institute, Linköping, Sweden. No. 42. Report, (1991).
[13] Lunne, Tom, and Arne Kleven. "Role of CPT in North Sea foundation
engineering". In Cone penetration testing and experience, pp. 76-
107. ASCE, (1981).
[14] Mayne, Paul W. Cone penetration testing. Vol. 368. Transportation
Research Board,(2007).
[15] Muduli, Pradyut Kumar, and Sarat Kumar Das. "CPT-based seismic
liquefaction potential evaluation using multi-gene genetic program-
ming approach". Indian Geotechnical Journal44, no. 1 (2014): 86-93.
[16] Otoko, George R., Isoteim Fubara-Manuel, Mike Igwagu, and Clem-
ent Edoh, "Empirical cone factor for estimation of un-drained shear
strength." Electronic Journal of Geotechnical Engineering 21 (2016):
6069-6076.
[17] Rémai, Zsolt. "Correlation of un-drained shear strength and CPT
resistance", Periodica Polytechnica Civil Engineering 57, no. 1 (2013):
39-44.
[18] Rezania, Mohammad, and Akbar A. Javadi, "A new genetic pro-
gramming model for predicting settlement of shallow foundations".
Canadian Geotechnical Journal 44, no. 12 (2007): 1462-1473.
[19] Robertson, P. K., and K. L. Cabal. "Guide to Cone Penetration Testing
for Geo-Environmental Engineering." (2008).
[20] Robertson, P. K. "Soil classification using the cone penetration test."
Canadian Geotechnical Journal 27, no. 1 (1990): 151-158.
APPENDIX: DATA SETS
Validation data set
L.L.
(%)
P.L.
(%)
P.I.
(%)
wc
(%)
γ
(t/m3)
Nk
60 26 34 46 1.7 18.6
134 33 101 69 1.6 14.8
95 30 65 66 1.6 16.4
83 28 54 56 1.7 16.7
109 31 78 64 1.6 15.2
136 33 103 69 1.6 14.5
40 21 19 41 1.8 17.3
82 34 47 60 1.6 19.7
86 34 52 58 1.8 18.4
58 27 31 59 1.8 18.6
84 34 50 59 1.6 19.6
51 26 26 57 1.7 17.9
118 40 78 68 1.5 18.8
53 26 27 49 1.8 18.5
128 32 96 57 1.7 13.8
84 26 58 67 1.6 15.3
146 34 112 57 1.7 13.1
43 24 20 40 1.7 18.9
49 23 26 43 1.8 17.9
54 26 28 62 1.7 18.5
72 32 40 60 1.7 19.5
101 30 71 59 1.6 15.5
128 33 95 66 1.6 14.0
81 33 48 56 1.6 20.1
82 34 49 55 1.6 19.6
102 30 72 74 1.6 15.1
87 34 53 36 1.8 18.2
43 21 22 33 1.9 19.3
38 21 17 36 1.8 16.3
126 33 93 72 1.6 14.2
156 36 120 69 1.6 15.0
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Training data set
L.L.
(%)
P.L.
(%)
P.I.
(%)
wc
(%)
γ
(t/m3)
Nk
94 30 64 53 1.7 16.9
132 34 98 57 1.7 13.7
93 29 63 36 1.8 13.4
109 31 79 66 1.6 15.3
136 34 103 83 1.5 14.3
76 28 48 35 1.8 16.6
100 30 70 47 1.7 15.5
90 29 61 63 1.6 16.4
141 34 107 56 1.7 12.7
92 36 56 59 1.9 18.4
41 21 20 41 1.7 17.8
72 27 45 52 1.7 16.6
73 31 43 58 1.8 18.8
93 35 58 57 1.7 18.5
97 38 59 61 1.6 19.8
80 28 52 52 1.7 16.5
140 33 107 59 1.6 13.2
142 34 108 59 1.6 12.8
95 30 66 57 1.7 16.9
120 32 88 59 1.6 14.1
53 26 27 60 1.7 18.4
72 29 43 64 1.7 18.3
112 42 71 68 1.6 20.2
41 21 20 49 1.7 17.5
53 25 28 49 1.7 18.6
72 29 42 58 1.6 18.3
53 25 28 48 1.8 17.3
48 24 24 52 1.7 18.6
68 29 40 51 1.7 18.8
49 22 28 26 1.8 17.0
51 26 26 46 1.7 19.1
65 29 35 47 1.7 20.2
72 31 41 59 1.6 21.3
131 33 98 62 1.6 14.8
41 22 20 44 1.7 17.2
48 25 24 49 1.7 18.8
117 41 77 58 1.6 18.1
77 31 46 45 1.7 18.8
97 35 62 57 1.6 18.9
93 29 64 59 1.6 16.1
111 32 79 72 1.6 15.4
104 30 74 63 1.6 14.9
91 29 62 70 1.6 16.7
92 29 63 70 1.6 16.2
107 31 76 76 1.7 15.4
57 25 32 67 1.6 17.8
78 32 46 37 1.8 18.3
157 39 118 54 1.7 13.4
72 29 43 38 1.8 17.9
75 30 45 37 1.8 18.4
85 34 50 36 1.8 18.2
56 24 31 41 1.7 17.8
70 28 41 66 1.6 18.8
48 20 28 44 1.8 16.1
65 27 39 33 1.9 17.9
87 30 57 37 1.8 18.8
48 22 25 50 1.6 17.5
56 26 31 47 1.7 17.3
73 31 46 38 1.8 20.4
122 32 90 50 1.7 14.3
88 29 59 67 1.5 15.2
104 31 73 63 1.6 15.1
86 29 57 69 1.6 16.1
111 32 80 69 1.6 15.6
122 32 90 71 1.6 14.5
101 31 70 73 1.6 17.1
105 31 74 55 1.7 15.5
91 29 62 69 1.6 15.8
123 32 91 68 1.6 14.0
101 29 72 62 1.6 15.0
117 32 86 70 1.6 13.6
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Paper Title: Predicting (Nk) factor of CPT test using (GP): Comparative Study of MEPX & GN7
Authors: Ahmed H. ELbosraty, Ahmed M. Ebid, Ayman L. Fayed
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Predicting (Nk) factor of CPT test using (GP): Comparative Study of MEPX and GN7
March 23,2019
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Predicting (Nk) factor of CPT test
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MEPX & GN7

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Predicting (Nk) factor of (CPT) test using (GP): Comparative Study of MEPX & GN7

  • 1. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 613 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org Predicting (Nk) factor of (CPT) test using (GP): Comparative Study of MEPX & GN7 Ahmed H. ELbosraty1 , Ahmed M. Ebid2 , Ayman L. Fayed3 Abstract— Static cone penetration test (CPT) is a broadly satisfactory and dependable geotechnical in-situ apparatus that gives brisk and honest substantial measure of data about soil classification, stratification and properties. Un-drained shear strength of clay (cu) is one of the principle soil parameters that could be sensibly evaluated from the (CPT) results, as it is specifically connected to the tip resistance through the experimental cone factor (Nk). Earlier researches showed that (Nk) value depends on type of soil, nature and stress history conditions and many other variables. Construction development in some locations with thick deposits of soft to very soft clays motivates extensive researches to define the reasonable value of the (Nk) factor for such types of clay. The performed study concentrated on utilizing the genetic programming technique (GP) to predict (Nk) value of clay using the consistency limits that can be easily determined in the laboratory. A set of 102 records were gathered from the CPT site investigations and corresponding consistency limits and other physical properties experiments, were divided into training set of 72 records and validation set of 30 records. Both (GN7) & (MEPX) software were used to apply (GP) on the available data. Four trials for each software with different chromosome lengths were performed to correlate the (Nk) factor with the clay consistency limits, water content (wc) and unit weight (γ) using training data set, then, the produced relations were tested using the validation data set. The four generated formulas using (GN7) showed accuracies ranging between 93% and 97% and coefficient of determination (R2 ) ranging between 0.7 and 0.9, while the other four formulas form (MEPX) showed accuracy not exceeding 95% and coefficient of determination (R2 ) ranging between 0.45 and 0.75. Index Terms— CPT, Consistency Limits, Genetic Programming (GP), Multi Expression Programming (MEP), Cone Factor (Nk). ——————————  —————————— 1 INTRODUCTION Lassic static cone penetration test (CPT) is one of the well- known site tests which carried out to characterize the soil formations and estimate their mechanical proprieties based on their penetration resistance. Today, modern (CPT) equipment is capable to measure many more parameters than penetration resistance such as pore water pressure, lateral soil pressure at rest, lateral elastic modulus of soil. Figure (1) shows (CPT) test overview and sample of its output. [3, 10, 15]. Many theories were introduced to simulate the behavior of the soil during static penetration process such as the bearing ca- pacity theory (Meyerhof 1961, Durgunoglu and Mitchell 1975), cavity expansion theory (Vesic 1972 and Yu and Houlsby 1991), the strain path method proposed by Baligh (1985), cali- bration chamber testing and the finite element analysis (Walk- er and Yu 2006). [1, 8, 9, 12, 17,19 and 20]. Although, many previous researches were carried out to corre- late tip resistance from (CPT) with other soil properties spe- cially the un-drained shear strength of clay (cu), but none of them derives a proper correlation due to the sophisticated be- havior of the clay which depends on many parameters such as initial stresses, pore-water pressure, penetration rate and over consolidation ratio. In addition, uncertainties in measured values make the correlation more difficult. [4, 14]. Previously suggested formulas to correlate (CPT) results with the un-drained shear strength of clay (cu) are summarized in many publications [3, 6, 9, 10, 15, and 16]. Many of those re- searches considered that (cu) proportional linearly with the corrected tip resistance of the cone as shown in equation (1) Nk q voc u σ− =c ….... (1) Where, cu : Un-drained shear strength of clay. qc : Tip resistance of the cone. σvo : Total overburden pressure. Nk : Empirical cone factor. Accordingly, most of the previous researches were concerned in estimating (Nk) value which correlates (CPT) with (cu). As summarized by Zsolt Rémai (2013) [17], typical values for (Nk) for different soil types has been suggested by many re- searchers. Lunne and Kleven (1981) [13] suggested that (Nk) varies between 11 and 19 for normally consolidated, Scandi- navian marine clays. Jörss (1998) [7] suggested that (Nk) equals 20 for marine clays and 15 for boulder clays. Gebre- selassie (2003) [5] proposed that (NK) value is ranged between 7.6 and 28.4 for different soil types. Finally, Chen (2001) [4] recommended (Nk) values varying between 5 and 12. C ———————————————— 1 Graduate Student, Department of Structural Engineering, Faculty of Engi- neering, Ain Shams University E-Mail: eng_elbosraty@yahoo.com 2 Lecturer, Department of Structural Engineering, Faculty of Engineering & Tech.., Future University, Egypt. E-Mail: ahmed.abdelkhaleq@fue.edu.eg 3 Associate Professor, Department of Structural Engineering, Faculty of Engineering, Ain Shams University E-Mail: ayman_fayed@eng.asu.edu.eg IJSER
  • 2. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 614 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org (a) (b) Figure (1) Cone Penetration Test (CPT): a) Test Overview, b) Output Example (after Paul W. Mayne and Jon M. Williams (2007)) IJSER
  • 3. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 615 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org 2 (GP) & (MEP) 2.1 Genetic programming (GP) (GP) is a direct application of genetic algorithm (GA) optimi- zation technique on a population of mathematical formulas to generate the most fitting formula for certain given points in a hyper-space. Accordingly, (GP) may be described as Multivar- iable Regression Procedure. (Koza,1994) (GP) is big title includes several techniques such as Linear GP, Cartesian GP, Compacted GP and many others. [2 ,11,18]. Classic (GP) procedure starts with randomly generating a population of mathematical formulas which are encoded in genetic form (chromosome form) and testing each formula using the training data set to calculate its fitness. Only the most fitting formulas (survivors) will be selected to generate the next cycle (or generation) using crossover and mutation operators, then the new population to be tested again to calcu- late their fitness and so on until accepted accuracy is achieved. 2.2 Multi Expression Programming (MEP) (MEP) is a technique to automatic generation of computer programs. Accordingly, it could be used to generate fitting mathematical formulas for certain data set. MEP differentiates from classic (GP) techniques by encoding multiple solutions in the same chromosome. Same as classic (GP), crossover is ap- plied in (MEP) using one Point Crossover technique, where one crossover point is randomly chosen and the parent chro- mosomes exchange the sequences at the right side of the crossover point. Also, both classic (GP) and (MEP) are sharing the same mutation technique where randomly selected gens (or symbols) are changed. Unlike classic (GP), the output of the (MEP) is a series of programming commands, if all these commands are mathematical expressions, then the output could be simplified in one mathematical expression just like classical (GP). 3 (GN7) & (MEPX) 3.1 (GN7) software (GN7) is the 7th version of classic (GP) software which was developed by the author in (2004) in C++[2]. Figure (2) shows the encoding technique and the principal of tree levels to measure the complexity of the mathematical formula. It is clear that complex of the formulas needs more levels to repre- sent it than simple ones. As shown in Figure (2). The chromo- some consists of two parts, “operators” and “variables”. The “operators” part contains the entire tree except the level 0 and has (2No. of levels - 1) genes. The “variables” part contains only the level 0 of the tree and has (2No of levels) genes. Therefore, the total number of genes in the chromosome is (2No. of levels + 1) genes [2]. (GN7) supports eight operators which are (=, +, -, x, /,Xy , e^, Ln) and support up to 7 levels of complexity. Regarding crossover procedure, it doesn’t support the classic one-point crossover technique, instated, it supports random crossover technique which was proposed by author, 2004 [2] to generate the new chromosomes by randomly selecting each gene from similar surviving chromosomes as shown from figure (3). Mu- tation is applied by replacing some randomly selected genes with random operator (in the “operators” part) or variable (in “variables” part). Since most mathematical formula have con- stant values, hence variables with constant values are used to present those constants. Usually, the following set of constants is used (1, 3, 5, 7 and 11). (GN7) uses the sum of squared errors (SSR) method to measure the fitness. Figure (2) Mathematical and Genetic Representation of Binary Tree (after A. Ebid 2004) Figure (3) Random Crossover Technique (after A. Ebid 2004) 3.2 (MEPX) software (MEPX) is free and open source software that uses (MEP) technique. This project started in 2001 and the first end-user for windows is released in 2015. Unlike (GN7), current version of (MEPX) has a graphical user interface (GUI). Both source code and compiled software could be freely downloaded from http://www.mepx.org. The software is easy to learn and of- fers many options to control the searching process as shown in figure (4), these options could be summarized in the following points: - Three types of problems (regression, binary classifica- tion and multi-class classification) - Two methods to measure error (mean absolute error and mean squared error) - 26 different mathematical, logical, statistical and trig- onometrical operators. - Two methods of crossover (uniform and one point crossover) - Two methods to generate constants (user defined and automatically generated) IJSER
  • 4. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 616 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org - Code length, is the number of genes on each chromo- some, it is a measurement for the complexity of the solution which is equivalent to number of levels in (GN7). Figure (4) screenshot of (GUI) of (MEPX) software 3.3 Comparison Bases In order to fairly compare the results of the two programs, the following points were considered: - Using same set of variables, liquid limit (L.L), plastic limit (P.L), plasticity index (P.I), water content (wc) and unit weight of clay (γ). - Using same constant values (1,3,5,7,11) - Using the same training and validation data sets - Using the same population size - Using same number of generations - Using same method to measure error (SSR) - Using same complexity level (code length) - Since the output should be mathematical formula, on- ly mathematical operators were used in (MEPX) - Unaccepted too complicated expressions such as mul- ti-power (x^(y^z)) and multi logarithms (log(log(x)) were eliminated from both programs. - For the best fitting formula of each trial, its accuracy was determine using equation (2) , the predicted val- ues of (Nk) were plotted against the experimental ones and the coefficient of determination (R2) was de- termined. rec cal NNk NkNk 100 100=(%)Accuracy exp exp × − − ∑ …(2) 4 PREDICTION OF (NK) USING (GN7) Four trials were carried out using (GN7) to predict the value of (Nk) factor using the training data set as follows: - 1st trial had only two levels of complexity (chromo- some length is 8 genes), Population size was 5000 chromosome, number of generations was 50 and the best formula was equation (3) LP LL . .6.3 7.32=Nk × − …(3) - 2nd trial had three levels of complexity (chromosome length is 16 genes), Population size was 10000 chro- mosome, number of generations was 50 and the best formula was equation (4) 56.2 . .12 )-(PILn.161=Nk −      × LL LP γ …(4) - 3rd trial had four levels of complexity (chromosome length is 32 genes), Population size was 20000 chro- mosome, number of generations was 50 and the best formula was equation (5) 79.1 .).( 20 . .21 .111=Nk 2 −         + + × LPLnLL LP …(5) - 4th trial had five levels of complexity (chromosome length is 64 genes), Population size was 40000 chro- mosome, number of generations was 50 and the best formula was equation (6) 19.5)5).()(2( )14.04( 3)/5(. .31=Nk −      −−− + ++ × LLLnPILn PILn LP γ γ …(6) Accuracies and coefficient of determination (R2) of training and validations sets for each one of the four trials are summa- rized in table (1). Figure (5) represent the correlation between the predicted (Nk) values using the equations (3),(4),(5),(6) and the measured ones. TABLE (1): SUMMARY OF ACCURACIES AND (R2 ) VALUES FOR EQUATIONS (3),(4),(5),(6) TrialNo. No.ofLevels Proposed Formula Accuracy % R2 Training Validation Total Training Validation Total 1 2 Eq. (3) 93 95 94 0.72 0.71 0.71 2 3 Eq. (4) 96 97 96 0.87 0.89 0.87 3 4 Eq. (5) 96 96 96 0.82 0.88 0.84 4 5 Eq. (6) 96 97 97 0.91 0.88 0.87 The following points could be noted from table (1): - Accuracies of all proposed formulas are ranged be- tween 93% to 97%, while (R2 ) values are ranged be- tween 0.71 to 0.91 which indicates good fitting - The enhancement in fitting between equations (4),(5),(6) is negligible, on other hand, the remarkable complexity difference between them makes equation (4) more favorable than the others. - None of the four proposed formulas contains water con- tent (wc) which indicates that (Nk) doesn’t depend on it. IJSER
  • 5. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 617 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org a) Trial(1) – Eq. 3 b) Trial(2) – Eq. 4 c) Trial(3) – Eq. 5 d) Trial(4) – Eq. 6 Figure (5) Relation between the Predicted and Measured (Nk) values for Developed Correlations using (GN7) 5 PREDICTION OF (NK) USING (MEPX) Four equivalent trials were carried out using (MEPX) to pre- dict the value of (Nk) factor using the training data set as fol- lows: - 1st trial had chromosome length of 8 genes, Popula- tion size was 5000 chromosome, number of genera- tions was 50 and the best formula was equation (7) IP LL . 55.11 =Nk − …(7) - 2nd trial had chromosome length is 16 genes, Popula- tion size was 10000 chromosome, number of genera- tions was 50 and the best formula was equation (8) [ ](P.I)LnP.IP.L11 .11 11 =Nk +++ + IP …(8) - 3rd trial had chromosome length is 32 genes, Popula- tion size was 20000 chromosome, number of genera- tions was 50 and the best formula was equation (9) ( )( )[ ]).ln(7).(6.1 . 7 )./7( ./7 =Nk IPIPLn IPIPLn IP −+++ …(9) - 4th trial had chromosome length is 64 genes, Popula- tion size was 40000 chromosome, number of genera- tions was 50 and the best formula was equation (10) 11. )5( P.I )5(11L.L11 =Nk 2 − + + IP Ln γ γ …(10) Accuracies and coefficient of determination (R2) of training and validations sets for each one of the four trials are summa- rized in table (2). Figure (6) represent the correlation between the predicted (Nk) values using the equations (7),(8),(9),(10) and the measured ones. IJSER
  • 6. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 618 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org a) Trial(1) – Eq. 7 b) Trial(2) – Eq. 8 c) Trial(3) – Eq. 9 d) Trial(4) – Eq. 10 Figure (6) Relation between the Predicted and Measured (Nk) values for Developed Correlations using (MEPX) TABLE (2): SUMMARY OF ACCURACIES AND (R2 ) VALUES FOR EQUATIONS (7),(8),(9),(10) TrialNo. CodeLength Proposed Formula Accuracy % R2 Training Validation Total Training Validation Total 1 8 Eq. (7) 93 93 93 0.44 0.54 0.52 2 16 Eq. (8) 94 94 94 0.53 0.63 0.58 3 32 Eq. (9) 93 94 94 0.53 0.58 0.56 4 64 Eq. (10) 95 95 95 0.63 0.76 0.67 The following points could be noted from table (2): - Accuracies of all proposed formulas are ranged be- tween 93% to 95%, while (R2 ) values are ranged be- tween 0.44 to 0.76 which indicates fair fitting - Equation (10) is the most accurate one and the only one that used unit weight (γ) variable which indicates the importance and the impact of this variable. - None of the four proposed formulas contains water con- tent (wc) which indicates that (Nk) doesn’t depend on it. 6 CCONCLUSIONS By comparing the summarized results in tables (1),(2), the fol- lowing points could be noted: - Although equation (4) is not the most accurate pro- posed formula, but considering its simplicity, it is still the most favorable one. IJSER
  • 7. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 619 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org - Formulas contains unit weight (γ) variable are more ac- curate than others regardless the used software, this re- flects the high correlations between (Nk) and (γ). - None of the proposed formulas regardless the used software contains water content (wc) which indicates that (Nk) doesn’t depend on it. - Although proposed formulas from (GN7) & (MEPX) almost have same accuracies for same level of com- plexity (code length), but coefficients of determination (R2) of (GN7) formulas are higher than those of (MEPX) which indicates the random crossover tech- nique of (GN7) is more efficient than the one point crossover technique of (MEPX). - It is also noted that (MEPX) is almost twice faster than (GN7), this may be because (MEPX) uses multi threads. REFERENCES [1] Aas, Gunnar, Suzanne Lacasse, Tom Lunne, and Kaare Hoeg. "Use of in situ tests for foundation design on clay." In Use of In Situ Tests in Geotechnical Engineering, pp. 1-30. ASCE, (1986). [2] Ahmed M. Ebid, Ezzat A. Fattah, Hossam E.A. Ali. "Applications of genetic programming in geotechnical engineering. " DOI: 10.13140/RG.2.1.1967.9203 (2004). [3] Boufrina, T., Bouafia, A., Panfilov, A. V., & Ter-Sarkisova, L. A. "Numerical modeling of CPT in clay to evaluate bearing capacity for shallow foundations." Проблемы и перспективы развития сельского хозяйства и сельских территорий. (2014). [4] Chen, C. "Evaluating un-drained shear strength of Klang clay from Cone penetration test." In International Conference on In situ Meas- urement of Soil Properties and Case Histories, In: Proceedings of the International Conference on In Situ Measurement of Soil Properties and Case Histories, Graduate Program, Parahyangan Catholic Uni- versity, pp. 141-148. (2001). [5] Gebreselassie, Berhane. "Experimental, Analytical and Numerical Investigations of Excavations in Normally Consolidated Soft Soils." (2003). [6] Hossain, Md Imran. "Evaluation of Un-drained Shear Strength and Soil Classification from Cone Penetration Test." (2018). [7] Jörß, O. "Erfahrungen bei der Ermittlung von cu-Werten mit der Hilfe von Drucksondierungen in bindigen Böden." Geotechnik 21, no. 1 (1998): 26-27. [8] Kim, Daehyeon, Younjin Shin, and Nayyar Siddiki. "Geotechnical design based on CPT and PMT." (2010). [9] Kim, Hobi, Monica Prezzi, and Rodrigo Salgado. "Use of dynamic cone penetration and clegg hammer tests for quality control of road- way compaction and construction." (2010). [10] Kim, Kwang Kyun, Monica Prezzi, and Rodrigo Salgado. "Interpreta- tion of cone penetration tests in cohesive soils." (2006). [11] Koza, John R. Genetic programming II, automatic discovery of reus- able subprograms. MIT Press. Cambridge, MA, (1992). [12] Larsson, R., and M. Mulabdic. Piezocone tests in clay. Swedish Ge- otechnical Institute, Linköping, Sweden. No. 42. Report, (1991). [13] Lunne, Tom, and Arne Kleven. "Role of CPT in North Sea foundation engineering". In Cone penetration testing and experience, pp. 76- 107. ASCE, (1981). [14] Mayne, Paul W. Cone penetration testing. Vol. 368. Transportation Research Board,(2007). [15] Muduli, Pradyut Kumar, and Sarat Kumar Das. "CPT-based seismic liquefaction potential evaluation using multi-gene genetic program- ming approach". Indian Geotechnical Journal44, no. 1 (2014): 86-93. [16] Otoko, George R., Isoteim Fubara-Manuel, Mike Igwagu, and Clem- ent Edoh, "Empirical cone factor for estimation of un-drained shear strength." Electronic Journal of Geotechnical Engineering 21 (2016): 6069-6076. [17] Rémai, Zsolt. "Correlation of un-drained shear strength and CPT resistance", Periodica Polytechnica Civil Engineering 57, no. 1 (2013): 39-44. [18] Rezania, Mohammad, and Akbar A. Javadi, "A new genetic pro- gramming model for predicting settlement of shallow foundations". Canadian Geotechnical Journal 44, no. 12 (2007): 1462-1473. [19] Robertson, P. K., and K. L. Cabal. "Guide to Cone Penetration Testing for Geo-Environmental Engineering." (2008). [20] Robertson, P. K. "Soil classification using the cone penetration test." Canadian Geotechnical Journal 27, no. 1 (1990): 151-158. APPENDIX: DATA SETS Validation data set L.L. (%) P.L. (%) P.I. (%) wc (%) γ (t/m3) Nk 60 26 34 46 1.7 18.6 134 33 101 69 1.6 14.8 95 30 65 66 1.6 16.4 83 28 54 56 1.7 16.7 109 31 78 64 1.6 15.2 136 33 103 69 1.6 14.5 40 21 19 41 1.8 17.3 82 34 47 60 1.6 19.7 86 34 52 58 1.8 18.4 58 27 31 59 1.8 18.6 84 34 50 59 1.6 19.6 51 26 26 57 1.7 17.9 118 40 78 68 1.5 18.8 53 26 27 49 1.8 18.5 128 32 96 57 1.7 13.8 84 26 58 67 1.6 15.3 146 34 112 57 1.7 13.1 43 24 20 40 1.7 18.9 49 23 26 43 1.8 17.9 54 26 28 62 1.7 18.5 72 32 40 60 1.7 19.5 101 30 71 59 1.6 15.5 128 33 95 66 1.6 14.0 81 33 48 56 1.6 20.1 82 34 49 55 1.6 19.6 102 30 72 74 1.6 15.1 87 34 53 36 1.8 18.2 43 21 22 33 1.9 19.3 38 21 17 36 1.8 16.3 126 33 93 72 1.6 14.2 156 36 120 69 1.6 15.0 IJSER
  • 8. International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 620 ISSN 2229-5518 IJSER © 2019 http://www.ijser.org Training data set L.L. (%) P.L. (%) P.I. (%) wc (%) γ (t/m3) Nk 94 30 64 53 1.7 16.9 132 34 98 57 1.7 13.7 93 29 63 36 1.8 13.4 109 31 79 66 1.6 15.3 136 34 103 83 1.5 14.3 76 28 48 35 1.8 16.6 100 30 70 47 1.7 15.5 90 29 61 63 1.6 16.4 141 34 107 56 1.7 12.7 92 36 56 59 1.9 18.4 41 21 20 41 1.7 17.8 72 27 45 52 1.7 16.6 73 31 43 58 1.8 18.8 93 35 58 57 1.7 18.5 97 38 59 61 1.6 19.8 80 28 52 52 1.7 16.5 140 33 107 59 1.6 13.2 142 34 108 59 1.6 12.8 95 30 66 57 1.7 16.9 120 32 88 59 1.6 14.1 53 26 27 60 1.7 18.4 72 29 43 64 1.7 18.3 112 42 71 68 1.6 20.2 41 21 20 49 1.7 17.5 53 25 28 49 1.7 18.6 72 29 42 58 1.6 18.3 53 25 28 48 1.8 17.3 48 24 24 52 1.7 18.6 68 29 40 51 1.7 18.8 49 22 28 26 1.8 17.0 51 26 26 46 1.7 19.1 65 29 35 47 1.7 20.2 72 31 41 59 1.6 21.3 131 33 98 62 1.6 14.8 41 22 20 44 1.7 17.2 48 25 24 49 1.7 18.8 117 41 77 58 1.6 18.1 77 31 46 45 1.7 18.8 97 35 62 57 1.6 18.9 93 29 64 59 1.6 16.1 111 32 79 72 1.6 15.4 104 30 74 63 1.6 14.9 91 29 62 70 1.6 16.7 92 29 63 70 1.6 16.2 107 31 76 76 1.7 15.4 57 25 32 67 1.6 17.8 78 32 46 37 1.8 18.3 157 39 118 54 1.7 13.4 72 29 43 38 1.8 17.9 75 30 45 37 1.8 18.4 85 34 50 36 1.8 18.2 56 24 31 41 1.7 17.8 70 28 41 66 1.6 18.8 48 20 28 44 1.8 16.1 65 27 39 33 1.9 17.9 87 30 57 37 1.8 18.8 48 22 25 50 1.6 17.5 56 26 31 47 1.7 17.3 73 31 46 38 1.8 20.4 122 32 90 50 1.7 14.3 88 29 59 67 1.5 15.2 104 31 73 63 1.6 15.1 86 29 57 69 1.6 16.1 111 32 80 69 1.6 15.6 122 32 90 71 1.6 14.5 101 31 70 73 1.6 17.1 105 31 74 55 1.7 15.5 91 29 62 69 1.6 15.8 123 32 91 68 1.6 14.0 101 29 72 62 1.6 15.0 117 32 86 70 1.6 13.6 IJSER
  • 9. International Journal of Scientific and Engineering Research (IJSER) PUBLICATION CERTIFICATE Paper Number: I0130603 Paper Title: Predicting (Nk) factor of CPT test using (GP): Comparative Study of MEPX & GN7 Authors: Ahmed H. ELbosraty, Ahmed M. Ebid, Ayman L. Fayed Type of the paper: (Please highlight) �Research �Application �Case Study �Survey �On-going �Other Evaluation: (Please highlight) Low High Significance of Contribution: 1 2 3 4 5 Originality of Content: 1 2 3 4 5 Technical Quality: 1 2 3 4 5 Clarity of Presentation: 1 2 3 4 5 Overall recommendation (Please highlight) Accept in current state Accept with minor revision Major Revision needed, recommend resubmission Reject Any additional comments: Paper Published in IJSER Volume 10, Issue3, March 2019 Edition (ISSN 2229-5518).
  • 10. ISSN 2229-5518 CERTIFICATE OF ACCEPTANCE International Journal of Scientific & Engineering Research (IJSER) Ahmed M. Ebid Predicting (Nk) factor of CPT test using (GP): Comparative Study of MEPX and GN7 March 23,2019 _______________ Visit us at: www.ijser.org THIS IS TO CERTIFY THAT OUR REVIEW BOARD HAS ACCEPTED RESEARCH PAPER OF Editor in Chief
  • 11. CERTIFICATE of PUBLICATION THIS ACKNOWLEDGES THAT Ahmed M. Ebid HAS SUCCESSFULLY PUBLISHED RESEARCH PAPER | Members | IJSER Review Board Panel | www.ijser.org WWW.IJSER.ORG MARCH 2019 Predicting (Nk) factor of CPT test using (GP): Comparative Study of MEPX & GN7