soil investigation report

1. P L
FINAL REPORT OF
GGEOTECHNICAL INVESTIGATION
A NUMBER OF FASCINATING AND LIFE-CHANGING TEMPLATES
PRESENTED IN A CLEAR AND CONCISE WAY
EDITED BY
SIRAJ ROKA ,SUDIP ABL
PRAJWAL GHIMERE,ASHIM OLI
BISHAL TMILSANA,PRAJWAL SIMKHADA
Kathmandu University
Dhulikhel
2023
SUBMITTED TO:AVISHEK SHRESTHA

2. 1
FINAL REPORT ON GEOTECHNICAL
INVESTIGATION
Group 7
May 10 ,2023

3. 2
Contents
1 Acknowledgement 4
2 Introduction 5
3 Location 5
4 About this study 6
4.1 Purpose of study . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2 Scope of Investigation . . . . . . . . . . . . . . . . . . . . . . . . . 7
5 Geotechnical Exploration 7
5.1 Field investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1.1 About SPT Test . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Surface and Sub surface exploration 9
6.1 Properties of ground material . . . . . . . . . . . . . . . . . . . . 9
6.2 Values Taken . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.3 Calculation Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.4 Final Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Lab Test and Results 11
7.1 Specific gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1.1 Observed values . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1.2 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2 Moisture content . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2.1 Observation table . . . . . . . . . . . . . . . . . . . . . . . 12
7.2.2 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.3 Particle size Distribution . . . . . . . . . . . . . . . . . . . . . . . 12
7.3.1 Observation Table . . . . . . . . . . . . . . . . . . . . . . . 13
7.3.2 Result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.4 Liquid Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.4.1 Observation Table . . . . . . . . . . . . . . . . . . . . . . . 14
7.4.2 Result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.5 Plastic Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.5.1 Result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

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8 Ground Water Table 15

5. 4
1 Acknowledgement
I am extremely grateful to Er. Avishek Shrestha sir for creating this learn-
ing platform for improving our cost foundation engineering skills. We deeply
appreciative of his exceptional support and guidance in teaching us how to
access information on our course subject, CIEG309. His contribution has
been invaluable to our learning.We would like to express my gratitude to our
respected teacher for providing us with valuable feedback that has helped us
improve our skills in information gathering, group discussion, reference se-
lection, and report writing. We also want to thank some of our classmate
for their direct or indirect assistance in completing this project on time.
Their help has been invaluable. The completion of this project would not
have been possible without the guidance, coordination, and assistance of our
teacher and friends. We are extremely fortunate to have received their help
throughout the project. We are deeply grateful for their support and we will
never forget their contributions.

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2 Introduction
This report presents the results of geotechnical investigation conducted, lab-
oratory results and recommendation for the proposed construction site i.e.
check dam at Batase, Kavre. This report covers boreholes drilled at various
locations including three boreholes. To determine how compact the soil lay-
ers were in the field, Standard Penetration Tests (SPT) and Dynamic Cone
Penetration Tests (DPCT) were carried out as efficiently as possible at 1.5m
depth intervals. Report is limited to SPT test defining parameters and speci-
fying safe bearing capacity of soil in which investigation work for three bore-
holes was carried out from 5 th April 2023.
For the safe and economic infrastructural development, it is important
that subsoil conditions at any proposed civil engineering site be properly
investigated prior to commencement of the final design or construction ac-
tivities. Generally, the overall investigation should be detailed enough to
provide sufficient information for the geotechnical engineer to reach conclu-
sions regarding the site suitability, design criteria and environmental im-
pact. Both laboratory and in situ or field techniques are routinely used to
obtain information about engineering properties of rocks and soils. This re-
port focuses on the standard penetration test (SPT) which is one of the rel-
atively cost-effective and informative field techniques most commonly used
in subsurface exploration.
3 Location
The site is located in Kavreplanchok district and is situated at Chaukot area.
The Geotechnical study is done for Bastase check Dam.

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Figure 1: Location
4 About this study
4.1 Purpose of study
The purpose of this site investigation is to determine the existing soil profiles
and engineering characteristics of the subsurface conditions to:
•Evaluate the soil and rock properties at proposed site.
•Determine the site’s suitability for construction a check dam
•Identify potential issues that could affect the stability and safety of dam.
•Develop recommendations for the design and construction of the dam
structures.
•Determine the type of foundation that would be suitable for the site,
•Identify suitable materials to be used in construction.
•Provide guidance for the design and construction.

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4.2 Scope of Investigation
The scope of investigation for this study comprises the following:
1. Making visits for site reconnaissance to collect information about the site
nature, thetopography of the site, and other properties concerning the
project site.
2. Drilling of two boreholes at the specified location of required depth and
conducting SPT at 1.5m interval depth.
2. Performing all necessary field and laboratory tests, to obtain physical
and mechanical properties of the subsurface soil.
3. Submitting the final geotechnical investigation report.
5 Geotechnical Exploration
Geotechnical exploration is the process of gathering information about the
soil and rock conditions at a site. This information is used to design and
construct safe and stable structures. Geotechnical exploration is typically
conducted by a geotechnical engineer or engineering geologist.This explo-
ration process typically involves a combination of field and laboratory ex-
ploration. The geotechnical exploration process typically begins with a site
visit and visual inspection of the area to be explored. This is followed by a
detailed site investigation, which may include drilling and sampling of soil,
conducting geophysical surveys and collecting data on groundwater levels.
Laboratory testing is then performed on the samples collected during the
investigation, to determine their physical and chemical properties. The re-
sults of the geotechnical exploration are then analyzed and interpreted by
engineers and other professionals to develop the recommendations for the
site design and construction.
There are a variety of methods that can be used for geotechnical explo-
ration, including:
• Soil borings: Soil borings are used to collect soil samples from the sub-
surface. The samples are then analyzed in a laboratory to determine
their physical properties, such as strength, compressibility, and per-
meability.
• Geophysical surveys: Geophysical surveys use electromagnetic or seis-
mic waves to map the subsurface. This information can be used to

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identify the depth and thickness of different soil layers.
The type of geotechnical exploration that is conducted will depend on the size
and complexity of the project. For small projects, a simple soil boring may
be sufficient. For larger or more complex projects, a more comprehensive
geotechnical investigation may be required.
Geotechnical exploration is an important part of the design and construc-
tion process. By gathering information about the soil and rock conditions at
a site, geotechnical engineers can help to ensure that structures are safe and
stable.
5.1 Field investigation
A field investigation is the process of collecting data on the physical prop-
erties and characteristics of the soil and rock that will support a structure.
This information is used by a foundation engineer to design a foundation
that can safely support the structure without causing any damage to the
soil or rock. For the site, three boreholes BH1, BH2 and BH3 was drilled.
5.1.1 About SPT Test
The standard penetration test (SPT) is an in-situ dynamic penetration test
designed to provide information on the geotechnical engineering properties
of soil. This test is the most frequently used subsurface exploration drilling
test performed worldwide.The test provides samples for identification pur-
poses and provides a measure of penetration resistance which can be used
for geotechnical design purposes. Various local and widely published inter-
national correlations that relate blow count, or N-value, to the engineering
properties of soils are available for geotechnical engineering purposes.
Penetration tests were executed through all strata. Sounding test data
were used to estimate soil strength parameter, subsoil distribution and pos-
sible existence of soft layer.Standard Penetration test (SPT) were carried out
in the boreholes at average depth intervals of 1.5 m. Spilt spoon sampler of
35mm internal diameter and 50 mm external diameter coupled with a stan-
dard cutting shoe at its lower end was driven into the ground at the base of
the borehole by means of a 63.5 kg hammer falling from a height of 760 mm.
After an initial 150 mm seating penetration the sampler was driven to a fur-
ther depth of 150mm twice to reach the final depth. The sum of the number

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of blows required to reach the two-last final 150 mm depth was recorded as
the N- value.
5.2 Sample Collection
The samples obtained in the split spoon barrel of SPT tube during SPT tests
were preserved as representative disturbed samples. The disturbed samples
recovered were placed in air-tight transparent plastic bags, labelled properly
for identification and finally sealed to avoid any loss of moisture. Only then
the samples were taken to the laboratory for the further investigation.
6 Surface and Sub surface exploration
6.1 Properties of ground material
According to our exploration and findings, a generalized subsurface soil char-
acteristic data visualized from two borehole is as presented in the table be-
low:
SNno Description Depth(m) SPT Value
15 30 45
1 0.86 6 21 42
2 0.71 5 60/12
3 0.83 3 3 3
Table 1: SPT Values
6.2 Values Taken
Hammer Efficiency=60
Correction for Borehole Diameter=1
Sampler Correction=1
Correction for Bar length=0.95

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6.3 Calculation Table
N60 15.2
Cohesion, kN/m2 (c) 0
Effective Stress (sigma), kN/m2 12.36
Overburden Correction 1.700939
SPT Value After Overburden Correction 25.85427
SPT Value After Dilatancy Correction 21
Unit Weight Value(KN/m3) 18 In correlation with SPT value)
Friction Angle 28
Saturated Unit Weight 21.033
6.4 Final Table
Depth,m Width of foundation, m
1 1.5 2 2.5 3
0.86 215.49 202.87 199.34 192.77 190.24
Table 2: Bearing Pressure
Depth,m Width of foundation, m
1 1.5 2 2.5 3
0.86 224.546 190.932 175.146 166.002 160.042
Table 3: Allowable bearing pressure based on settlement of 40mm, kN/m2
Depth,m Width of foundation, m
1 1.5 2 2.5 3
0.86 215.49 190.932 175.146 166.002 160.042
Table 4: Allowable bearing pressure is the minimum of A and B:

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7 Lab Test and Results
7.1 Specific gravity
The specific gravity of soil is the ratio of the mass of a given volume of the
material at a stated temperature to the mass of an equal volume of de-aired
or gas-free distilled water at a stated temperature. The specific gravity of
soil is used in the phase relationship of air, water, and solids in a given
volume of the soil.
The specific gravity of soil is used in relating a weight of soil to its volume
and in the calculation of phase relationship, i.e. the relative volume of solids
to water and air in a given volume of soil. The specific gravity is used in
the computations of most of the laboratory tests and is needed in nearly all
pressure, settlement, and stability problems in soil engineering.
7.1.1 Observed values
Wt of pycnometer=520gm
Wt of pycnometer with water=1550gm
Wt of sample=32gm
Wt of all=1570
7.1.2 Conclusion
Hence, specific gravity of soil at norma room temperature was found to be
2.667
7.2 Moisture content
In almost all soil tests, natural moisture content of the soil is to be deter-
mined. The knowledge of the natural moisture content is essential in all
studies of soil mechanics. To sight a few, natural moisture content is used
in determining the bearing capacity and settlement. The natural moisture
content will give an idea of the state of soil in the field.

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7.2.1 Observation table
Wt of container
(gm)
Wt of containr with sample
(gm)
Wt of dry Sample
(gm)
Water content
(gm)
22.2 45.24 42.21 15.16
22.66 42.03 38.57 15.06
22 41.22 38.44 16.9
7.2.2 Conclusion
The natural moisture content of the soil sample is 15.7%.
7.3 Particle size Distribution
Sieve analysis is the method to determine the relative proportion of grain
size of the given sample of soil. The grain size distribution is used for soil
classification under the USCS standards. The test procedure involves the
shaking the soil through sieve of different size and weighing the soil re-
tained on each sieve. The purpose of doing this analysis is to find weather
the aggregate sample is good for the mix or not. The sieve analysis is gener-
ally applied to the grain size greater than 75 m. The uniformity coefficient
(Cu) and coefficient of curvature/gradation (Cc) is determined through the
formula:
Cu = D60/D10 (1)
Cc = (D2)30/D10 ∗ D60 (2)
Where, D60 = Sieve size to 60 percent finer soil.
D30 = Sieve size to 30 percent finer soil.
D10 = Sieve size to 10 percent finer soil.
Soil is well graded if Cu > 4-6 and Cc is between 1 and 3.
Soil is poorly graded if Cu is nearly equal to 1.

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7.3.1 Observation Table
Figure 2: Particle Disrtibution Table
Figure 3: particle distribution curve

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7.3.2 Result
Diameter of particle at 60% finer (D60) = 1.375 mm
Diameter of particle at 30% finer (D30) = 0.174 mm
Diameter of particle at 10% finer (D10) = 0.0449 mm
Coefficient of Uniformity (Cu) = 30.188
Coefficient of Curvature (Cc) = 0.469
The Coefficient of Uniformity (Cu) = 30.188, but the Coefficient of Cur-
vature (Cc) = 0.469. Since the Cu is higher, it can be concluded that the soil
sample consists of different ranges of particle size, i.e. the larger range of
the particle sizes; however, as the Cc (0.469) is outside the range of 1-3 for
“well graded”, the soil sample taken is found to be gap graded or bimodal,
i.e. absence of intermediate particle sizes exists.
7.4 Liquid Limit
Liquid limit is significant to know the stress history and general properties
of the soil met with construction. From the results of liquid limit, the com-
pression index may be estimated. The compression index value will help us
in settlement analysis. If the natural moisture content of soil is closer to liq-
uid limit, the soil can be considered as soft if the moisture content is lesser
than liquids limit, the soil can be considered as soft if the moisture content
is lesser than liquid limit. The soil is brittle and stiffer.
7.4.1 Observation Table
Figure 4: Liquid Limit

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Figure 5: Graph
7.4.2 Result
Required Liquid limit obtained from graph is 29.58.
7.5 Plastic Limit
Plastic limit (PL) is the moisture content at which a fine-grained soil can-
not be remolded without cracking. The plastic limit test requires repeated
rolling of a soil sample into a thread until it reaches a point where it crum-
bles.
7.5.1 Result
Hence obtained soil is Non Plastic.
8 Ground Water Table
Determination of the location of ground water table is an essential part of
any exploratory programme as the groundwater level affects the pore water
pressure and hence the shear strength pf soil. The position of groundwater
can be estimated through observations of open wells at the site or in the

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vicinity. Boreholes can also be used for recording water levels by allowing
the water in boring to reach equilibrium level. It is easy in sandy soils as
water gets stabilized very quickly within few hours. But in clayey soil it
might take many days. The readings should be made at least 12 to 24 hrs
after boring and compared with water levels in the wells existing in that
area.