Civil Engineering Technology

18: Civil Engineering Technology
First Name Last Name
Higher National Certificate/Diploma in Construction and the Built Environment
April 5, 2020

Task 1
a) Earthwork is a method that includes drilling, moving and compacting the surface at a site.
Four processes involved in earthworks, such as; excavation, haulage, unloading and
compaction. Earthworks were primarily done at the early construction stage. The
execution of the earthwork during the specified planning time is also the cornerstone to
the success of the project on schedule, which indicates that the earthwork is a significant
undertaking the building process (Berryman, OCarroll, & Fowler, 2016). There are 3
forms of work in earthworks:
(a) Site clearing. Act to eliminate light brush, bushes, existing construction and
vegetation
(b) Digging of foundations and trenches. The limited scale of the excavation happens
while the wide bulk earth moving plant need not be utilized
(c) bulk excavation. The excavation that allows the more intensive excavation work,
including cutting and filling and foundation excavation.
The following are the equipment required by the foundation earthworks: Hydraulic excavator,
Tractor / trucks, Kassi, Pickaxe, Rammer, Wedge, Boning Rod, Iron Pan, hydraulic compactor,
Sledge Hammer etc. Scope of Operation for Excavation and Backfilling of the land; Setting out
corner benchmarks, Survey for ground level, Survey for top level, digging to accepted
depth, Installation of dewatering wells and interlinking trenches, Development of building
boundaries, Installation of safety bunds and drains (Lamont, 2012).
b) A pile is a vertical structural feature with a deep base, pushed or sunk deep underground
at the construction site. Precast piles are pushed to the ground using a pile system. Driven
piles are built of reinforced concrete. timber or steel. They are lined with rebars and are
also pre-stressed. Driven piles, as contrasted to digging shafts, are better as the material
shifted by moving the piles constricts the adjacent soil. Foundations depending on driven
piles also have bands of piles bound by a pile cap to disperse loads greater than a pile
they can carry. Pile caps and isolated piles are usually attached to grade beams to bind the
base structures around each other; lighter structural components rely onto the grade
beams, whereas heavy elements bear exclusively on the pile cap (CHUDLEY, 2017).
Pile structures are used in the following scenarios:

 where the soil becomes thin on the land thus insufficient soil bearing capacity.
 If a structure contains very strong, compact loads, like the high-rise building.
There are two types of pile foundations:
i. End bearing piles; the pile end lies on a surface of extremely hard ground or rock.
The load of the structure is passed to the firm layer via the pile. In a way, this pile
is behaving like a column. The main concept here is the pile end lies on the
ground, which is the boundary between a soft and solid base. The load, thus,
overrides the poor layer and is securely passed to the firm ground/ layer.
ii. Friction piles; in this type, the pile passes the load of the structure to the firm
ground through the pile height, by means of friction. In other terms, the whole
framework of the pile, that is cylindrical in form, acts to move the stresses to the
ground.
c) Culvert is characterized as a tunnel network built beneath interstates which make
available cross drains or electrical cables across sections. It is fully covered by soil or
water. Pipe culvert, arch culvert and box culvert are popular forms of culvert. When a
single pipe culvert is required, a large diameter culvert is mounted. If the channel breadth
is larger, then a series of pipe culverts are installed to adequately handle the expected
flows.
The underpass or subway is a tunnel comprising a lane or a pedestrian path passing under
a bridge or railroad. There are three main methods for constructing underpasses:
i. Precast concrete units: are mostly assembled as standard elements and may be
mounted as complete units, portal frame parts, or as individual roof and wall
structures.
ii. In situ concrete. In situ concrete underpasses are built using same techniques as
any underground tunnel infrastructure.
iii. Thrust-bored units. Thrust-bored units include the attachment of bentonite for
cushioning. As a way of transferring the thrust load, the units will be in close
contact with the edge rather than with the semi-formed locking plate. This
deburring procedure will require communication with the outside of the jack but

be capable of obtaining a bonding material from the inside of the jack. It can be
achieved by shaping a discounted mortar-filled joint before applying.
d) methods and techniques utilized in large and complex earth moving operations and deep
excavations include;
 Full Open Cut Method; This classified into two principal forms, namely sloped full
open cut and cantilever full open cut. The first form is believed to be economic
because the construction side will be sloping and requires not any protection for the
shell of the base. Even so, whether the slope is substantially moderate or the trench is
relatively wide, it would be costly. The second form requires a retaining wall to
protect the foundation wall soil to keep the foundation wall from crumbling, but does
not entail backing or slopes. Consequently, it must not be conclusively asserted that
the approach has a higher cost impact. The budgetary approach may be differentiated
on the basis of the findings of study, architecture and assessment (Griffiths &
Radford, 2012).
 Bracing Excavation Method; Excavation bracing is the positioning of longitudinal
struts beside the retaining wall to support the excavation wall with structural strength.
The bracing framework consists of columns, struts, middle pillars, end and corner
braces. Earth pressure is transmitted to the longitudinal struts via the wall, and the
aim of the corner and end braces is to reduce the wall span while increasing the
number of struts. Center posts protect struts from collapsing from their own weight
(Griffiths & Radford, 2012).
 Anchored Excavation Methods: In this method, anchors are mounted to overcome the
weight of the earth. The confined section of the anchor supplies the stabilizing power
acting towards soil stress whereas the unrestrained section of the anchor transition
strain is transferred to the head of the anchor which moves loads to the retaining wall
(Harris, McCaffer, & Edum-Fotwe, 2013).
 Island Excavation Methods: In this approach, the middle of the excavation zone is
excavated and dug up soil is put next to the retaining wall to produce a slope.
 Top Down Excavation Methods: in this methodology, the development starts from the
top to the bottom of the foundation. the design of the frame continues upon