CBFS ?Soil Improvement? Geotechnical Problems Presentation بعد ماسعره (Code: A41/ date28/5/2020 ) How many words: 6 pages each source 3 PowerPoint each

CBFS ?Soil Improvement? Geotechnical Problems Presentation بعد ماسعره

(Code: A41/ date28/5/2020 )

How many words:

6 pages each source

3 PowerPoint each source

***********************

Guide line

read all these instructions

Take 3 different sources from internet on the same topic

1- This source only ::

-Journals paper2 pages – 1ppt

-Conference paper2 pages -1ppt

-Case studies 2 pages -1 ppt

summarize these 3 sources to 2 pages each

And after making summary for each source to 2 pages you will make 3 different presentation… Means 3 summaries and 3 presentation and the presentations points must be different In wording from word file i.e source summary.

These are some file pdf or references

He can using to summarizations the topic

Also there is PowerPoint he can see how making PowerPoint (add drawing and figures)

But don’t copy from this PowerPoint

To remember 6page

3 PowerPoint for each source

Thank you Soil Improvement ( CIVL)
Spring 2020
Stabilization of expansive soil using deep soil mixing
Dear Student
1.
Prepare a PowerPoint presentation about a specific topic. The title of research for
each student is shown in the table listed below.
2.
Use the internet as main source of information:
 Journals papers
 Conference papers
 Case studies
 Videos
3.
You should mention the source of the information’s or references.
4.
Save the original source of information as PDF.
5.
Prepare a PowerPoint presentation.
6.
Each presentation should include, but not limited to:
Introduction
Objectives
Literature review including description, Properties of the soil analysis or
design methods
Use figures graphs and tables if possible.
Conclusions
7.
You can add a Video
International Journal of GEOMATE, Oct., 2017, Vol.13, Issue 38, pp.09-15
Geotec., Const. Mat. & Env., ISSN:2186-2990, Japan, DOI: http://dx.doi.org/10.21660/2017.38.6527
THE ESTIMATION OF BEARING CAPACITY AND SWELL
POTENTIAL OF DEEP SOIL MIXING ON EXPANSIVE SOIL BY
SMALL SCALE MODEL TEST
*Yulvi Zaika1 and Arief Rachmansyah2
1,2
Engineering Faculty, Brawijaya University, Indonesia
*Corresponding Author, Received: 14 June 2017, Revised: 13 July 2016, Accepted: 16 Feb. 2017
ABSTRACT: Deep Soil Mixing (DSM) is a ground modification technique to improve soil characteristic.
This paper explain the result of laboratory experiment of deep soil mixing (DSM) in small scale. The model
have been constructed to estimate field condition. The important properties of expansive soil such as the
strength and swelling were investigated. The fly ash was used as binder material to enhance strength and
mitigate swell potential. However optimum binder dosage, water – binder ratio and geometrical column (length,
diameter and spacing) influenced performance of DSM. Variation of length and spacing of column could be
established by considering active zone and the area ratio in the single square arrangement. The required
treatment area are determined based on tolerable swelling and allowable bearing capacity. The small scale of
DSM construction showed significant improvement of swell and strength properties compare with untreated
soil. The empirical model are presented in this research provided reasonable predictions of strength and
swelling for in situ condition.
Keywords: Expansive, Strength, Swelling, Improvement, Deep Mixing
the product of weathering process of mudstone
(residual soil) of the Lidah Formation. The Lidah
Formation (TQs) composed by blue grey mudstone
with lenses of carbonates sandstones and limestone.
This geological formation is formed in a shallow
marine environment during the Pliocene Pleistocene (Ratman, et al., 1998). This residual soil
type has generally high shrink-swell characteristics
(known as high expansive soil), because of its high
contents of montmorilonite minerals. Bojonegoro
district is one of area in this formation. The
expansive characteristics of the clayey soil can
cause cracks in the floor of building and the road,
and prone the landslide (Fig. 2).
1. INTRODUCTION
One of geotechnical problems encountered in
the construction of transportation infrastructure in
the north part of East Java is wide spread expansive
clayey soil (Fig.1). In this region it is founded two
types of clayey soil.
Fig.1 Map of the spread of soft soil and expansive
soil in the northern part of East Java, Indonesia and
transportation infrastructure (Rachmansyah, 2014).
Fig. 2 Typical cracks of the pavement that were
built on the residual soil of Lidah Formation in the
North East Java
The first type is the sediment soil that as the
product of sedimentation materials carried by the
river Bengawan Solo and sedimentation in wetlands
(Qa). This soil is generally fine-grained, and
contains a lot of organic matter. The thickness of
young soft sediment soil can reach 40 m depth
(Wesley, 2010). The second type of clayey soil is
Some additive materials such as cement, lime,
fly ash, silica and various chemical compound were
applied to improve the soil properties that is shrink
swell characteristics. In an industrial context, fly
ash usually refers to ash produced during
combustion of coal. Fly ash is generally captured by
electrostatic precipitators or other particle filtration
9
International Journal of GEOMATE, Oct., 2017, Vol.13, Issue 38, pp.09-15
equipment before the flue gases reach the chimneys
of coal-fired power plants. Because of it contains
such as silica (SiO2), iron oxide (Fe2O3), aluminium
oxide (Al2O3), and calcium oxide (CaO), fly ash can
be categorized as pozzolanic materials.
Considering the successful and rapid nature of
chemical based DSM in stabilizing soft soil, the
same technology was considered to expansive soil.
The purpose of this study was to explore the change
of strength and swell potential of improvement with
DSM in different geometric parameters (length,
diameter and spacing of columns) in small scale
laboratory experiment. Laboratory result on field
cores indicated that both field stiffness and strength
are about 20% to 40% less than the corresponding
laboratory prepared soil samples (Madhyannapu et
al, 2010). Some of numerical studies have been
carried out to understand the behavior columnsupported embankment system, assuming linear
elastic or linear elastic perfectly plastic but Yapage
et al. (2014) obtained strain softening constitutive
behavior for cement stabilized clay for DSM
column. Application and evaluation of DSM was
developed by Madhyannapu at al. (2014) to propose
the stepwise design methodology.
∆ = ∑ =
,
+ ,

′ ,
(1)
′ ,
Where:
Cs,i : swell index
eo,i : initial void ratio
p’f,i: final stress (overburden ± any change of total
stress)
p’s,i: initial swell pressure (suction).
hi : thickness of each layer
According to Rao at. al. (1988) in unsaturated
expansive soil the initial swell pressure could be
measured as the corrected swell pressure, p’s,i from
the constant volume type oedometer test. The final
stress state, p’f,i, accounts for the overburden stress,
as well as any net change in total stress from either
excavation or surcharge type loading. The Eq. (1)
was modified into Eq. (2).
∆ = ∑ =
, ,

+ .

′ , ,
′ , ,
(2)

Where the parameter , , , . , ′ , ,
and ′ , , are composite properties of layer i in
the treated ground. The parameter could be
estimated as shown following:
2. DEEP SOIL MIXING METHOD
The use of the soil mixing to improve the
engineering properties of soft soil and contaminated
soil is very well known for a long time. In this
method soils are mixed in situ with stabilized
binders. The stabilized material will produce the
higher strength, lower permeability, and lower
compressibility and lower swell potential than
native soil. The improvement becomes possible by
action exchange at the surface clay minerals,
bounding of soil particles and/or filling of void by
chemical reaction product. The widely used binder
are cement and lime, gypsum, fly ash and secondary
products are also used.
The soil mixing can be divided into two general
methods: the deep soil mixing and shallow soil
mixing. The DSM is an applied for in situ
stabilization of soil to minimum depth of 1.5 m
(depend on mass stabilization). Generally DSM can
be performed in two techniques of mixing, dry
mixing and wet mixing. In the wet mixing, the soil
is mixed with additives in binder slurry, while the
dry mixing soil mixed with additives in binder
powder.
, , = , . + , . ( − )
′ , , = ′ , . + ′ , . ( − )
(3)
(4)
Where subscript soil= untreated soil properties
subscript col = treated soil, ar = replacement volume
ratio.
Because of initial void ratio and bulk unit weight
for treated and untreated are the same and constant
with depth and the composite properties , , ,
′ , , were also constant with depth, the Eq.(2)
became more simple:
∆ = ∑ =
, ,
+ .

′ ,,
′ , ,
(5)
2.2 Bearing Capacity of Composite Ground
The improvement bearing capacity of expansive
soil also important in application of DSM. Some
methods to calculate bearing capacity of composite
ground (end bearing column) are expressed:
(1) Weighted method
2.1 The Heave of Expansive Soil and Composite
Ground
= + (1 − )
The model for predicting the heave of expansive
subsoil was based on the variation of swell
pressures with depth and is presented in the
following equation (Fredlund and Rahardjo, 1993):
(6)
(2) Broms (2000); Bouassida and Porbaha (2004)
Method
10
International Journal of GEOMATE, Oct., 2017, Vol.13, Issue 38, pp.09-15
= 0.7 + (1 − )
Swell potential was percentage of swell under 1psi surcharge of sample compacted at optimum
water content to maximum density in Standard
AASTHO Compaction Test. Set the swell gauge to
zero and record the time of the start of test. The test
will be stopped when the swell terminated.
(7)
Where:
cuc: undrained shear strength of column
cus: undrained shear strength of soil(untreated)
quc: unconfined compressive strength of column
α : replacement area ratio
λ : 5.5 (Bergado at al., 1994)
5. MATERIAL AND METHOD
2.3 Replacement Volume Ratio
5.1. Soil Properties
Estimate the stabilized volume ratio (if the
treatment was not end bearing column) is required
to reduce overall swelling to tolerable swelling
(heave).
The diameter of DSM column depend on the
availability of local DSM rigs. The area ratio of
square arrangement could be calculate based on Eq.
8.
The characteristics of expansive soil in this
study are shown Table 1.
=

+
=

�

.
Table 1. Characteristics of expansive soil
Characteristics
Value
Liquid Limit (LL)
73.9%
Plastic Limit(PL)
30.4%
Shrinkage Limit(SL)
2.8%
Plasticity Index (PI)
43.1%
USCS
CH
(8)
Where a col = area of column DSM, dcol =
diameter of column DSM and scc is space between
2 columns.
Based on specification of PI and LL was proposed
by Horz and Gibbs (1956), Raman, V (1967), Chen
(1988) and Snethen at.al (1977) the degree
expansion of soil is height.
3. BEARING CAPACITY IMPROVEMENT
5.2 Box Model and Soil Preparation of Loading
Test
The improvement soil characteristic is well
understood by using Bearing Capacity Ratio or
Bearing Capacity Improvement (BCI) that can be
determined based on ultimate bearing capacity and
bearing capacity of treated soil (DSM). Formulation
of BCI can be written as
=
( )
Prime element that used is box, made of fiber
glass with length 100 cm, width 50 cm and height
30 cm. The box use L profile as the frame and it
made to be rigid enough. Fiberglass used as box to
make observation easier in laboratory (Fig.3).
The loading test performed on the untreated soil
with 27.9 % moisture content and dry unit weight
12.88 kN/m3 and treated soil in 25.8% water content
and 15% fly ash (based on previous research).
Compaction is controlled from weight of soil that is
loaded into the box with a volume that is required.
The fly ash and soil are mix in dry condition.
The holes in treated soil test are made by using
a steel pipe of the same size with a diameter of DSM
column (2cm). In this experiment attempted to vary
spacing and depth to the composition of a single
square pattern (Fig.4)
Treated soil is inserted into the hole with several
layers. Each layer was compacted. The number of
collisions is done by way of a preliminary study to
obtain desirable density. The DSM construction are
cured in 3 days.
(9)

Where:
Pu (I): ultimate bearing capacity with DSM
Pu : ultimate bearing capacity native soil
4. SWELL POTENTIAL
Determination of swell potential is quite
important in design of foundations on expansive
soils. The swelling tendencies of expansive soils are
quantified by the swelling potential and/or free
swell. Swell potential or volume change is defined
as the ratio of increase in height to the initial height
of the soil sample compacted at optimum moisture
content in a consolidation ring and soaked under a
surcharge of 6.9 kPa (1 psi) , Seed et al. (1962).
=
−

%
(10)
Where, Hi : initial height of sample, Hf : final height
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International Journal of GEOMATE, Oct., 2017, Vol.13, Issue 38, pp.09-15
strength (qu) before and after improvement. The
parameter of shear strength, cu is obtained in this
test.
(1)
6. RESULTS AND DISCUSTION
(2)
(10)
(5)
(4)
(6)
10
(1)
6.1 Strength of soil improvement
(3)
30
(7)
15
Clay soil performances significant increasing of
strength when mixed with fly ash. The Table 3
shows cu or cohesion of undrained shear strength
in undisturbed, compact untreated and treated soil
sample.
(1)
(8)
(11)
(9)
5
(12)
50
where :
1. Steel frame
2. Hydraulic piston
3. Load cell
4. Piston
5. Lvdt
6. Cylinder plate
7. Plate, (5x5x2) cm
8. DSM column
Floor
Table 3 Undrained shear strength of such condition
expansive soil
Sample
Water content
cu
(%)
(kN/m2)
Undisturbed
49.46
25.3
Compacted soil
27.8 (omc)
64.3
Treated soil
25.8 (omc)
98.1
9. Untreated soil
10 .Fiber glass box 50x50x30 cm
11. Load cell reading
12. Lvdt reading
Fig. 3 Box experiment and loading test
The strength of expansive soil increases 155%,
289% by compaction method and mixed by fly ash
in optimum content respectively.
Column DSM
Plate
6.2 Spacing and Length Column Effect to
Strength and Settlement
Fig. 4 Single square model
One the most important analyses of DSM is
control of settlement of soil. Fig. 5 shown the
relation between stress and settlement of soil. The
untreated soil reached ultimate stress at 380 kPa. At
the same stress, the treated soil by DSM column
underwent small settlement. It made sense the
treated soil was stiffer than untreated one.
Variation of length and spacing of columns can be
seen in Table 2. There are two variations of the
floating column and an end bearing column.
Table 2 Column Length and Spacing
Parameters
cm
Length (L)
B, 2B, 3B
Spacing(S)
D,1.25D, 1.5D
Where: B= width of loading plate (square) = 5 cm,
D= diameter of column=2 cm.
0
200
400
stress (kPa)
600
800
1000
1200
0
Settlement (mm)
1
5.3 Soil Preparation and Swelling Test
Swelling tests were applied for untreated and
treated soil in the same condition (water content,
dry density, cure time) in CBR mold. There are
some variation of columns are made in CBR mold
for swelling test. The amount of column established
different replacement volume ratio. The test is
conducted to obtain relationship between
replacement volume ratio of soil and swell potential.
The relation will be used to estimate swell potential
in small scale model.
2
3
4
5
6
7
8
9
untreated soil
S=D; L=B
S=1.25D; L=B
S=1.5D: L=B
S=D; L=2B
S=1.25D;L=2B
S=1.5D; L=2B
S=D; L=3B
S=1.25D; L=3B
S=1.5D; L=3B
Fig.5 Relation between stress and settlement with
variation of length and column spacing
5.4 Unconfined Compressive Strength Test
The longest and closest column reached peak load
value. The result showed linear elastic perfectly
plastic behavior of DSM columns. Based on Euro
Unconfined compressive strength tests was
applied to investigate the change of undrained shear
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International Journal of GEOMATE, Oct., 2017, Vol.13, Issue 38, pp.09-15
Soil Stab (2012), the curve is linear up to the long
term strength (creep strength) and then the exceeded
load is assumed to be constant as shown in Fig.6.
Bearing capacity (kPa)
1200
1000
σcol
Ecol
1
σcreep (creep strength)
800
600
y = 0.0115×2 + 9.7956x + 404.26
400
200
0
0.0
Deformation,ε
20.0
40.0
60.0
80.0
Replacement volume ratio (%)
Fig. 8 Influence replacement volume ratio to
bearing capacity
6.3 Bearing Capacity Improvement (BCI)
6.4 The Swell Potential of Improved Soil
BCI is a measure that indicates the effect of
treatment on the bearing capacity of soil. Based on
3 variations of spacing and length of column,
relation between Bearing Capacity Improvement
and the parameters could be analyzed. The
experiment result gives the highest BCI is 2.73 for
the longest and nearest column spacing and the
lowest one is 1.147 for the shortest and widest space
column (Fig.7).
The observation of swell potential for DSM
method was done by variation of number of column
soil improvement. In this case a lot number of
column will give height the volume of treated soil.
The relationship between replacement volume
ratio and swell potential is shown in Fig. 9.
Swell Potential (%)
Fig. 6 Stress and deformation in column stabilized
soil (Euro Soil Stab)
3.0
BCI
2.8
2.6
L=B
2.4
L=2B
2.2
L=3B
2.0
y = 0.0002×2 – 0.0522x + 4.1661
0 10 20 30 40 50 60 70 80 90 100
1.8
Replacement volume ratio (%)
1.6
1.4
Fig. 8 Improvement of replacement volume ratio to
swell potential
1.2
1.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0.75
1
1.25
1.5
1.75
The regression analysis was applied to the
relationship and gave the formulation as follows:
S/D
Fig. 7 BCI of soil for different spacing and length
of DSM columns
= . − . + .
Length and spacing of columns arrangement
have effect to the replacement volume ratio than
these give impact to increase of the bearing capacity
of the soil as shown in Fig.8. In this study the
relation between replacement volume ratio and
bearing capacity is nonlinear. But based on Eq. 6
and 7, the relations is linear for end bearing column.
But Bouassida, M. (2016) suggest prediction for the
bearing capacity of treated soil by the DSM method
with wide range of cohesion ratio and replacement
area used limit analysis method. It will considered
more valid and reliable than the previous method.
(11)
Where x = replacement volume ratio and y =
swell potential. The equation could be used to
estimate swell potential of DSM in small scale
model. The increasing of replacement volume ratio
will decrease swell potential. There are some
factors that influence swell potential such as
characteristic expansive soil, type of binder, water
content, curing time and mixing methodology.
The estimation of swell po…
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