Geotechnical Engineering Report: Site Investigation and Design

This geotechnical engineering report provides a comprehensive analysis of a construction project site. It begins with an introduction to the project, followed by an examination of soil layer consistency based on SPT-N values. The report then presents a cross-section of the ground layers derived from borehole logs, classifying the soil and detailing its properties. A detailed construction sequence is outlined, including temporary propping, demolition, pile construction, and foundation development. The report also addresses the layout and design of retaining walls, including preliminary design aspects and load cases. Preliminary design calculations for retaining walls are presented, considering various load types and their combinations. The report is a valuable resource for understanding geotechnical engineering principles and practical applications in construction projects.

Geotechnical Engineering
Group members:
1. First Name Second Name (Group coordinator)
2. First Name Second Name
3. First Name Second Name
Institution

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1. Introduction
This report informs on specific geotechnical aspects of a design project considered on the
proposed site of the project was initially used as a storage area for a petrochemical factory and
has since been identified for construction work. The name of the client is……………………….,
and the project location is at …………………………The scope of the work include on the study
of the consistency of the soil layers as derived from SPT-N values, provision of the cross section
of the ground layers based on the available 3 borehole logs, suitable construction sequence
adoptable, and preliminary design considerations of the project.
2. Soil layer consistency
The consistency of soil layers based on SPT-N values is derived as in table-1.
SPT-N value Consistency Unit weight (moist
ym)
Unit weight
(submerged y¿)
0-4 Very loose ¿ 100 ¿ 60
5-10 Loose 95-125 55-65
11-30 Medium dense 110-130 60-70
31-50 Dense 110-140 65-85
¿ 51 Very dense ¿ 130 ¿ 75
Table-1. Soil layers consistency derived from SPT-N values.
3. Cross section of the site’s ground layer
From the three borehole logs, it is evident that the soil exhibits non-cohesive properties.
Generally, the soil is classified as sand with inconsiderable proportions of clayey soil. Between
depths 0m to not more than 8 m of investigation, the following figure-1 best presents a cross
section of the ground layers of the site based on the information given in 3 borehole logs.
Sandy loam, brown with occasional roots and

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organics.
Sand, grey at first becoming dark grey at depth. Fine
grained, uniform, silica sand. A dune sands.
Sand, dark brown indurated sand, slightly cemented,
“coffee rock”
Sand, light brown becoming yellow with depth. A
fine grained, uniform silica sand. Dune sand.
Clayey sand, appearance of sandstone. Grey/brown,
medium grained sand grains.
Sandstone, grey medium grained sandstone.
Figure-1. Cross section of the ground layers of the site.
4. Construction sequence.
A. Transitory prop the ground floor slab. Introduce raking shores to the thruway
holding divider.
B. Disassemble the edge carport dividers for the most part down to ground floor
section level, except for the divider bordering the adjoining emergency exit where
the divider will be dismantled to a dimension around 500mm over the ground
floor slab level (as a result of the contiguous 'raised' walkway).
C. Break out gaps in ground and cellar floor sections for piles to be built.
Incorporates cutting of existing concrete encased steel down stand bars inside the
ground floor section.
D. Build piles utilizing smaller than normal pile rig. (Utilizing propped ground floor
chunk as stage for the piling rig).
E. Get rid of the existing ground floor slab, leaving set up the raking shores to the
roadway holding divider.
F. Develop supporting in hit and miss style, to the full edge of the storm cellar.
G. Modify the raking shores that are propping the thruway holding divider, with the
goal that they sit on the supporting and not the current basement floor slab.
H. Break out and lessen the rest of the cellar floor level down to top of
supporting/topping bar level.

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I. Push and burrow the sewer vent rings to the stairwell. Cut spaces into the sewer
vent rings, continue to develop the lower basement floor piece and insitu
confronting (in lifts) inside the round stairwell.
J. Remove the highest points of the piles, cast the topping pillar and associate it to
the supporting and insitu looking in the round stairwell.
K. Uncover inside the new basement story. Brief prop the highest point of the
touching piled divider as removal continues.
L. When uncovered, build the lower basement floor section.
M. Build the insitu solid facings. Decidedly associate the facings to the insitu
concrete in the stairwell.
N. Cut the sewer vent rings.
O. Cast the upper basement floor slab.
P. Evacuate impermanent propping to the adjoining piled divider (wall).
Q. Build the ground floor section.
R. Expel the raking shores that are propping the expressway holding divider.
S. Continue with the rest of the structure development.
This sequence is as represented in figures-2/5. Successful project completion includes a
structured process in phases of project initiation and planning, executions, monitoring and
control, and project completion. The construction phase is typically represented in figure-3. The
basic project sequence is as summarized in figure-4.

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Figure-2. Sequence of construction to be adopted.

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Figure-3. Typical sequence showing construction process.
Figure-4. Basic project sequence.

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Figure-5. Adopted sequence of construction illustrated.
5. Layout of the retaining walls
A general layout of the retaining walls around the proposed building (figure-6) and also the
pedestrian access from the car park to this building is as shown below in figure-7.
Figure-6. Retaining walls layout and design.

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Figure-7. pedestrian access from the car park
6. Preliminary design aspects.
Consider retaining wall and forces as in figure-8. Below

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Figure-8. Retaining wall and interaction of forces.
The preliminary designs of the retaining wall structures is as tabulated:
Case 6.1 and 6.2
Load Cases (per 1m wide strip)
(water level used for analysis: 100-yr)
When RL=17.5 m
Load Type Load Description Fz y Fy z Mx @
P2
[kN/m] [m] [kN/m] [m] [kN-
m/m]
D Header SW (1) -0.30 5.67 -0.65
D * Backwall SW (2) -2.40 6.00 -6.00
D * Wall SW (3) -6.30 3.50 0.00
D * Stem SW (4) 0.00 0.00 0.00
D DL from Superstructure -19.82 2.50 19.82
D DL from Approach Span -2.81 6.66 -8.88
L LL from superstructure -7.60 2.50 7.60
L LL from approach span -3.80 6.66 -12.01
W Wind from Superstructure -0.24 23.50 1.44
WL Wind Load from Moving LL -0.07 23.50 0.40
BF Longitudinal (Braking) Force 0.00 0.00 0.00

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CF Long. Portion of Centrifugal Force 0.00 0.00 0.00
T Temperature loads -2.97 23.50 17.82
E * Soil SW between z3 and z2 (7) 0.00 0.00 0.00
E * Soil SW between z4 and z3 (8) 0.00 0.00 0.00
E * Lat. Soil Pressure -3.47 22.17 16.18
E * LL Surcharge -0.99 24.50 6.93
EQ Header Inertia Force (1) -0.07 32.25 1.00
EQ * Backwall Inertia Force (2) -0.54 27.50 5.40
EQ * Wall Inertia Force (3) -1.42 20.50 4.25
EQ * Stem Inertia Force (4) 0.00 0.00 0.00
EQ * Soil Inertia Force (7) -1.30 27.50 12.96
EQ * Soil Inertia Force (8) -0.97 20.50 2.92
EQ * Soil Inertia Force (9) 0.00 0.00 0.00
EQ * Seismic Soil Pressure -8.78 23.86 55.85
EQ * Superstructure EQ Reaction -1.49 23.50 8.96
E (water) * Vert. Effect of Water Table on Heel Side (7) 0.00 0.00 0.00
E (water) * Vert. Effect of Water Table on Heel Side (8) 0.00 0.00 0.00
E (water) * Horiz. Effect of Water Table on Heel Side 0.00 0.00 0.00
E (water) * Horiz. Effect of Water Table on Toe Side 0.00 0.00 0.00
B Buoyancy - Header (1) 0.00 0.00 0.00
B * Buoyancy - Backwall (2) 0.00 0.00 0.00
B * Buoyancy - Wall (3) 0.00 0.00 0.00
B * Buoyancy - Stem (4) 0.00 0.00 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
*
* 0.00
Note: (1) "*" indicates that trapezoid function was used to obtain the resulting force and the coordinate of its applic
"**" indicates additional input by user

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Overstress Factor not
Included
Ovestress Factor Includ
Overstres
s Load Combination Fz Fy Mx @ P Fz Fy Mx
Factor [kips/ft] [kips/ft] [kip-ft/ft] [kips/ft] [kips/ft] [kip
1.00 Group I -43.0 -4.5 23.0 -43.0 -4.5
0.80 Group II -31.6 -4.7 28.8 -25.3 -3.8
0.80 Group III -43.0 -4.6 23.8 -34.4 -3.7
0.80 Group IV -43.0 -7.4 40.8 -34.4 -5.9
0.71 Group V -31.6 -7.7 46.7 -22.6 -5.5
0.71 Group VI -43.0 -7.6 41.6 -30.7 -5.4
0.75 Group VII -31.6 -14.6 95.6 -23.8 -11.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
1.00 xxx 0.0 0.0 0.0 0.0 0.0
min = -43.0 -11.0
max = 0.0 0.0
Notes: (1) Load combination values obtained via the following matrix multiplication:
LC[nLC,1] = [ M[nBLC, nLC] ]T x BLC[nBLC,1]
includ
e Zb Zt σb σt zb zt
coeff [m] [m] [kN/
m2]
[kN/
m22] [m] [m]
calculated directly (always present)
1 23.5 31.5 0.3 0.3 23.5 31.5
1 13.5 23.5 1.05 1.05 17.5 23.5
0 6 13.5 1.05 1.05 13.5 13.5

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1
1
1
1
1
1
1
1
1
1 23.5 31.5 0 0 23.5 31.5
0 13.5 23.5 0 0 13.5 23.5
1 0 31.5 1.11 0 17.5 31.5
1 0 31.5 0.071 0.071 17.5 31.5
calculated directly (always present)
1 23.5 31.5 0.068 0.068 23.5 31.5
1 13.5 23.5 0.236 0.236 17.5 23.5
0 6 13.5 0.236 0.236 13.5 13.5
1 23.5 31.5 0.162 0.162 23.5 31.5
1 13.5 23.5 0.162 0.162 17.5 23.5
0 6 13.5 0.162 0.162 13.5 13.5
1 0 31.5 1.228 0.455 17.5 31.5
1
0 23.5 31.5 0 0 23.5 23.5
0 13.5 23.5 0 0 13.5 13.5
0 6 6 0.000 0.000 6 6
0 6 6 0.000 0.000 6 6
0 31.5 33 0.086 0.086 31.5 31.5
0 23.5 31.5 0.128 0.128 23.5 23.5
0 13.5 23.5 0.448 0.448 13.5 13.5