EARTH MOVING EQUIPMENTS

Introduction• Construction equipments can be classified into:

Earth moving Equipment Hauling Equipment Hoisting Equipment Conveying Equipment Aggregate and concrete production Equipment Pile driving Equipment Tunnelling and rock drilling Equipment Pumping and dewatering Equipment

Earth Moving Equipment

They can be further classified into Excavating Equipment Excavating and Earth moving Equipment

• Operations such as excavation, digging of large quantities of earth, moving, compacting, levelling etc. are performed using earth moving equipment.

Excavation Equipment 1 Power Sovels• Used to excavate earth and to load the trucks.

• Can excavate all types of earth, except hard rock.

• It may crawler or wheel mounted.

• Crawler mounted have low speed but effective in unstable soil.

• Wheel mounted are effective on firm ground.

• Its size depend upon size of work.

• Size of power shovel (bucket size) varies from 0.375 to 5 m³

Operation

• It shall moved into the required position.

• Bucket stick is lowered and cables are moved such a way that the bite is made into the ground.

• By moving the bucket forward the earth get excavated.

• Then the bucket is swung back to the required position and by opening the flap the excavated earth is unloaded into the truck.

Applications• Suitable for close range works.• Capable of digging hard materials• Used in various types of jobs, such as digging in road

works, gravel banks etc.

OutputDepends on• Class of material• Depth of cutting• Angle of swing• Job condition• Skill of operator

2 Back Hoe

• An excavating machine.• Used to excavate natural surface on which it rests.• To excavate trenches, grading works which require

precise control of depths.

Operations• Digging action results from the drag or pull of bucket

towards the machine.• The boom is set at desired angle.• The hoist cable is pulled in and the drag cable is

released, thus moving the bucket to required position.• By pulling the cable the bucket is filled.• The bucket is lifted by raising the boom and then

swinging to dumping position.

Applications• Suitable for digging below machine level.• Can be efficiently used to trim or dress the surface

avoiding manual effort.

3 Drag Line

• It has a long light crane boom and the bucket is loosely attached to boom through cables.

• It can dig and dump over larger distances than a shovel can do.

• Used for digging below its track level and handling softer material.

• Drag lines can be crawler or wheel or truck mounted.

•

Operations• Bucket is lowered by releasing both drag and hoist cable.• Hoist cable is slackened and the drag pull is applied• The earth get filled up and the bucket attains a horizontal

position.• When required dumping height is obtained, the is swung

to the position of dumping and the drag brake is applied.

Applications• Used for digging softer material• It has long reaches• Can be used in the excavation of canal

4 Clamshell• Bucket is in the shape of a shell fish.• The front end consist of crane boom with a specially

designed bucket.

Operations• Bucket is lowered with the shells open till a good contact is

made with the ground.• Then the shells are closed• The weight of the bucket enables it to dig into the material,

thereby filling it.• Then hoisted and swung to the position of dumping.

Applications• Used for handling loose materials such as crushed rocks,

gravel etc.• Can be used for removing materials from cofferdams,

sewer manholes etc.

5 Trenching Machines• Used for excavating trenches for laying pipelines, sewers,

cables etc.• Quick operation giving required depth and width.

Wheel Type

• Depth upto 3 m.• Width - .3 m to .6 m.• Power driven wheel provided with no. of detachable

buckets.• A belt conveyor is used for discharging the earth.

Ladder Type

• Consist of a telescopic ladder or a boom.• Depth upto 10 m.• Width of 3 m. • Not suitable for muddy and rocky soils.• With the help of gears speed can be adjusted.• There are two endless chains on which detachable

buckets are mounted.

EXCAVATING AND EARTH MOVING EQUIPMENTS

1 Scrapers• Used for digging and long distance hauling of ploughable

materials.• A self operating machine which digs and picks up its

own load through scrapping the ground and hauls it over the required distance.

• They are either cable or hydraulically operated.• Classified depending on the type tractor used to pull

themcrawler tractor pulledwheel tractor pulled

2 Bull Dozers

• Consist of heavy steel blade mounted on the front of the tractor.

• Blade pushes the material from one place to another.• Tractor can be wheel or crawler type.

Classification Based on1. Position of Bladesa) With blades perpendicular to the direction of movement

(bull dozers) b) Blades set in angle with the direction of movement(angle

dozers)

2. Based on mountinga) Wheel mountedb) Crawler mounted

3. Based on the controla) Cable controlledb) Hydraulically controlled

3 Tractors• Used for pushing and pulling other equipments

or heavy loads.• Used for agricultural purposes.• Tractors can be classified into

Crawler Type• Speed does not exceed 12kmph.• Used to move bull dozers, scrapers and wagons on

rough roads.• Not used in bituminous road.• It consist of chains which can effectively pull machines

in loose or muddy soil.

Wheel Type • Speed can exceed 50kmph.• Used for long distance hauling in good roads.• Engine is mounted on 4 wheels.

Earth Compacting Equipment

1. Smooth Wheel rollers2. Sheep foot rollersa) Ordinary sheep foot rollerb) Convertible rollerc) Turn foot roller3. Pneumatic tyred roller

Smooth wheel rollers• Plain steel rollers, self propelled type.• Weight – 5 t0 15 tonnes• Used for ordinary rolling work where deep

compaction is not required, the principle application being in road work.

• They have one front and 2 rear wheels• The rear wheels has larger diameter and front one

being wider.• The weight of the roller can be increased by using

hollow wheels which can be filled with water or sand ballast.

• They compact only the top small thickness of earth and its effect does not reach the bottom.

Sheet Foot Rollers• For compacting earth in embankments and canals where

compaction deep into the layers is required.• They produces good compaction throughout the thickness

of the layer when the soil is clay or cohesive and impervious.

• The roller consist of hollow steel drum and have projected feet or projections mounted on the surface which are arranged around the wheel at 100 to 200 mm c/c along the axis.

• Weigh upto 15 tonnes or more and travel at a speed of 25km/h.

• As roller moves over the surface, the feet penetrate the soil to produce a kneading action and a pressure to mix and compact the soil from bottom to top.

• Penetration of feet decreases after repeated passages

Pneumatic Tyred Rollers• Consist of a base or platform mounted between two axles,

the rear of which has one more wheel than the front.• The tyres must be so arranged that the tracks of the

forward wheels lie in between the tracks of the backward wheels.

• Most suitable for compacting fine grained soil and well graded sands.

• They are self propelled and the ballasting id done using either water, sand or pig iron to increase the self weight

• Major advantage – ability to control the ground contact pressure by

• Altering the weights of machine• Increasing the no. of wheels• Increasing the tyre width & changing the contact area of

tyre