answer should be 15-30 pages View Side by Side Synchronous Scrolling AYOUT REFER

Question

answer should be 15-30 pages

View Side by Side Synchronous Scrolling AYOUT REFERENCES MAILINGS REVIEW VIE One Page Switch Macros OMutiple ses New Arange Splt 0e Reset Window Postion Windows Page WidthWindow A Macros Zoom 100% Window Zoom ASSIGNMENT: ile a report on Earthworks Machineries: Excavating Loading and Hauling Compacting Grading and Finishing Comp With respect: The function How it works to move and transport earths Sizes available Production Rate Job Efficiency Typical sites where these machines are most appropriate to used in.

Explanation / Answer

Excavating and loading equipments.

1. BACKHOE:Backhoe comprises a bucket on the end of an articulated boom, set on a pneumatic tyred or crawler tractor unit. The boom, bucket arm and bucket are usually controlled by hydraulic rams. Back-acters operate by digging towards the machine in an arc from a small distance above the surface on which the machine stands to a position vertically below the outer edge of the machine. The maximum depth of excavation is related to the length of the boom and machines with depth capacities between 2.6 and 6 m are in common use. Long reach machines with nominal reach and depth capacities up to 18 to 14m respectively are also available. Buckets are available for back-acters in different sizes up to 3cum., depending on the power of the machine and the use. Loading is generally carried out by lifting the bucket and swinging the boom away from the working face to the awaiting haulage vehicle. Alternatively, material can be dumped adjacent to the machine

2. FACE, FRONT OR LOADING SHOVEL: Face, front or loading shovel is constructed in a similar manner to a back-acter except the boom; bucket arm and bucket operate in the opposite direction, i.e. up and away from the machine. Generally used for excavating faces upto about 8m high and stockpiles. Buckets are available in different sizes upto 4cum (heaped) depending on the power of the machine. Loading is carried out in a similar manner to the back-acter, although some machines have bottom dump buckets to increase the speed of loading. It is useful in excavating soils, weak rocks and blasted rocks from faces in cutting etc. some larger excavators can be converted from back-acters to face shovels.

3. FORWARD LOADER:

Forward loader consists of a pneumatic tyred or crawler tractor at the front of which is mounted a wide bucket that can be moved in a vertical plane. Excavation is carried out by driving the machine towards and the bucket into the material; the bucket is then turned and lifted upwards, thus catching and excavating the material. The hauling vehicle is loaded by driving the loader to and emptying the bucket into the body of a vehicle. Loaders are generally used to excavate the materials at and for a distance above ground level and can be used to push or haul material in the bucket over a short distances. Modern loaders have hydrostatically powered buckets and the smaller units may be equipped with a back-acters (i.e. backhoe loader)

GENERAL CHARACTERISTICS OF FORWARD LOADER

Used for loading, backfilling, grabbing and light dozing

Set on pneumatic tyres with wide bucket on front

Payload capacity-700 g

Breakout force at bucket edge-3500 kg

Overall length-5.23 m

Overall width-2.00 m

Dump angle-41 degree

Rollback-53 degree

Max height-4.165 m

Dump height-3.365 m

5. DRAGLINE:

Dragline equipment is operated from cranes or similar plant with a long boom. Excavation is done by pulling a bucket suspended on a cable towards the machine by a second cable. Thus, draglines are especially suited for the excavation of soft and loose materials from a distance at a level beneath or slightly above their tracks and may be used to excavate under water. Excavated material can be removed directly to a stockpile or loaded into haulage vehicles or conveyer hoppers by rotating the machine with the bucket in the upward position.

6. GRAB:

Grab consists of a cable or hydraulically controlled bottom-opening bucket suspended from a crane or a lifting arm. The bucket is opened and dropped on to a material to be removed. It is then closed and the material caught between the jaws lifted in the grab bucket and discharged onto stockpiles or into waiting haulage vehicles. Grabs are typically used for the excavation of pits or trenches and loading to and from stockpiles.

2. Hauling equipments:

1.Cranes

Cranes are used to lift materials and even in demolition. They commonly move building supplies, drilling supplies, or soil with cables, sheaves and a hoist. Mobile cranes are mounted onto flat cars, trucks, or other mobile platforms with trusses. Fixed cranes cannot move and are fixed onto steel towers. Thus, fixed cranes can reach higher, farther, and can support greater loads.  

2.Bulldozers

Bulldozers are normally used to create pilot roads, loosen hard soils, shift dirt, and work in terrain that is too tough for normal trucks. Bulldozers come with either a track base or a wheel base. Track-based bulldozers are better for sandy or muddy areas because the weight of the bulldozer is spread across a greater surface area.  

3.Excavators

Excavators are equipment used for digging holes, demolishing buildings, and lifting heavy loads to name a few. They have an extendable arm with a digging bucket attached to the end and come in many different sizes.  

4.Loaders

Loaders, like bulldozers, can be wheel-based or track-based. Their primary use is to load loose materials onto a conveyor belt or into a dump truck. The dump truck or conveyor belt then moves the materials away. Loaders are also used to move machinery.  

5.Tractors

Tractors work at much slower speeds but can be hooked up to do most any job. One can add buckets, blades, backhoes, or quick hitches to a tractor. They also have the power to push or pull other construction equipment.  

6. DumpTrucks

Trucks are used to haul materials on roads because the hauling cost for trucks is low compared to other construction equipment. Dump trucks commonly move sands, dirt, soils, and clay. Articulated dump trucks are available to use in tougher terrain. Hauling trucks are used to move equipment from one location to another.

capacity:

The capacity of hauling equipment is expressed in one of three ways:

gravimetrically by the weight of the load it will carry (in tons), by its struck rear-dump body volume (in cubic yards), or by its heaped rear-dump body capacity (in cubic yards). The hauling capacity of Army dump trucks is normally expressed gravimetrically: 5-ton and 20-ton. Conversely, the capacity of loading equipment is normally expressed in cubic yards. The unit weight of the various materials to be transported may vary from as little as 1,700 pounds per LCY for dry clay, to 3,500 pounds per LCY for trap rock for weights of common materials). Always make sure that the volumetric load does not exceed the gravimetric capacity of the truck.

3.compaction equipments:

A. light compaction

1.Rammers:

Rammers are used for compacting small areas by providing impact load to the soil. This equipment is light and can be hand or machine operated. The base size of rammers can be 15cm x 15cm or 20cm x 20cm or more.

For machine operated rammers, the usual weight varies from 30kg to 10 tonnes (6 lbs to 22000 lbs). These hammers with 2- 3 tonnes (4400 to 6600 lbs)weights are allowed to free fall from a height of 1m to 2m (3ft to 7ft) on the soil for the compaction of rock fragments.Rammers are suitable for compacting cohesive soils as well as other soils. This machine in areas with difficulty in access.

2. Vibrating Plate Compactors:

Vibrating plate compactors are used for compaction of coarse soils with 4 to 8% fines. These equipments are used for small areas. The usual weights of these machines vary from 100 kg to 2 tonne with plate areas between 0.16 m2 and 1.6 m2.

3. Vibro Tampers:

Vibro tampers is used for compaction of small areas in confined space. This machine is suitable for compaction of all types of soil by vibrations set up in a base plate through a spring activated by an engine driven reciprocating mechanism. They are usually manually guided and weigh between 50 and 100 kg (100 to 220 lbs).

B. Heavy Soil Compaction Equipments:

These compacting machines are used for large areas for use on different types of soils. The heavy compaction equipments are selected based on moisture content of soil and types of soil. Following are different types of these equipments:

Road rollers use the weight of the vehicle to compress the surface being rolled (static) or use mechanical advantage (vibrating). Initial compaction of the substrate on a road project is done using a padfoot drum roller, which achieves higher compaction density due to the pads having less surface area. On large freeways a four wheel compactor with padfoot drum and a blade, such as a Caterpillar 815/825 series machine, would be used due to its high weight, speed and the powerful pushing force to spread bulk material. On regional roads a smaller single padfoot drum machine may be used. The next machine is usually a single smooth drum compactor that compacts the high spots down until the soil is smooth, and this is usually done in combination with a motor grader to get a level surface. Sometimes at this stage a pneumatic tyre roller would be used. These rollers feature two rows (front and back) of pneumatic tyres that overlap, and the flexibility of the tyres provides a kneading action that seals the surface and with some vertical movement of the wheels, enables the roller to operate effectively on uneven ground. Once the soil base is flat the pad drum compactor is no longer used on the road surface. The next course (road base) would be compacted using a smooth single drum, smooth tandem roller or pneumatic tyre roller in combination with a grader, and a water truck to achieve the desired flat surface with the right moisture content for optimum compaction. Once the road base is compacted, the smooth single drum compactor is no longer used on the road surface (There is however an exception, if the single drum has special flat-wide-base tyres on the machine). The final wear course of asphalt concrete (a.k.a. asphalt or blacktop in North America, or macadam in England) is laid using a paver and compacted using a tandem smooth drum roller, a three-point roller or a pneumatic tyre roller. Three point rollers on asphalt were very common once and are still used, but tandem vibrating rollers are the usual choice now, with the pneumatic tyre roller's kneading action being the last roller to seal off the surface.

Rollers are also used in landfill compaction. Such compactors typically have padfoot or "sheep's-foot" drums, and do not achieve a smooth surface. The pads aid in compression, due to the smaller area contacting the ground.

1. Smooth Wheeled Rollers:

Smooth wheeled rollers are of two types:

(i) Static smooth wheeled rollers

(ii) Vibrating smooth wheeled rollers

(i)smooth wheeled roller: The most suitable soils for these roller type are well graded sand, gravel, crushed rock, asphalt etc. where crushing is required. These are used on soils which does not require great pressure for compaction. These rollers are generally used for finishing the upper surface of 0the soil. These roller are not used for compaction of uniform sands.

The performance of smooth wheeled rollers depend on load per cm width it transfers to the soil and diameter of the drum. The load per cm width is derived from the gross weight of the drum.

The smooth wheeled rollers consists of one large steel drum in front and two steel drums on the rear. The gross weight of these rollers is in the range of 8-10 tonnes (18000 to 22000 lbs). The other type of smooth wheel roller is called Tandem Roller, which weighs between 6-8 tonne (13000 to 18000 lbs).

The performance of these rollers can be increased by increasing the increasing the weight of the drum by ballasting the inside of drums with wet sand or water. Steel sections can also be used to increase the load of the drum by mounting on the steel frame attached with axle.

The desirable speed and number of passes for appropriate compaction of soil depends on the type of soil and varies from location to location. About 8 passes are adequate for compacting 20 cm layer. A speed of 3-6 kmph is considered appropriate for smooth wheel rollers.

2.Vibrating smooth wheeled rollers

In case of vibrating smooth wheeled rollers, the drums are made to vibrate by employing rotating or reciprocating mass.

These rollers are helpful from several considerations like:-

(i) Higher compaction level can be achieved with maximum work

(ii) Compaction can be done up to greater depths

(iii) Output is many times more than conventional rollers

Although these rollers are expensive but in the long term the cost becomes economical due to their higher outputs and improved performance. The latest work specifications for excavation recommends the use of vibratory rollers due to their advantage over static smooth wheeled rollers.

3. Sheepsfoot roller Roller:

Sheepsfoot rollers are used for compacting fine grained soils such as heavy clays and silty clays. Sheepsfoot rollers are used for compaction of soils in dams, embankments, subgrade layers in pavements and rail road construction projects.

Sheepsfoot rollers are of static and vibratory types. Vibratory types rollers are used for compaction of all fine grained soils and also soil with sand-gravel mixes. Generally this roller is used for compaction of subgrade layers in road and rail projects.

As seen in picture above, sheepsfoot rollers consist of steel drums on which projecting lugs are fixed and can apply a pressure upto 14kg/sq cm or more. Different types of lugs are namely spindle shaped with widened base, prismatic and clubfoot type.

The weight of drums can be increased as in the case of smooth wheeled rollers by ballasting with water, wet sand or by mounting steel sections.

The efficiency of sheepsfoot rollers compaction can be achieved when lugs are gradual walkout of the roller lugs with successive coverage. The efficiency is affected by the pressure on the foot and coverage of ground obtained per pass. For required pressure and coverage of ground, the parameters such as gross weight of the roller, the area of each foot, the number of lugs in contact with the ground at any time and total number of feet per drum are considered.

The compaction of soil is mainly due to foots penetrating and exerting pressure on the soil. The pressure is maximum when a foot is vertical.

4. Pneumatic Tyred Rollers:

Pneumatic tyred rollers are also called as rubber tyred rollers. These rollers are used for compaction of coarse grained soils with some fines. These rollers are least suitable for uniform coarse soils and rocks. Generally pneumatic tyred rollers are used in pavement subgrade works both earthwork and bituminous works.

The use of a pneumatic roller (or rubber tire roller) is vital in the compaction process of asphalt paving, in that, it is able to conform to the surface being paved. Steel drum rollers do a great job in the initial phase of rolling, but they also bridge some areas of the asphalt mat being laid, whereas, the pneumatic roller kneads the hot mix asphalt, working each of the 9 oscillating tires into the asphalt mat. Not only does this achieve denser compaction, but it also drives the bigger aggregate in the mix down, and brings the fine aggregate to the top, actually sealing the asphalt better to eliminate voids and preventing water intrusion. We use a rubber tire roller on every paving job, even using it on medium to large size asphalt repairs. In order to achieve the proper compaction and density of the asphalt and to ensure a long lasting, smooth pavement surface, the use of a rubber tire roller in the paving process is paramount.

Pneumatic rollers have wheels on both axles. These wheels are staggered for compaction of soil layers with uniform pressure throughout the width of the roller.

The factors which affects the degree of compaction are tyre inflation pressure and the area of the contact. The latest rollers have an arrangement to inflate the tyre to the desired pressure automatically. The total weight of the roller can be increased from 11.0 tonne to 25.0 tonne or more by ballasting with steel sections or other means.

5. Grid Rollers:

Grid rollers are used for compaction of weathered rocks, well graded coarse soils. These rollers are not suitable for clayey soils, silty clays and uniform soils. The main use of these rollers are in subgrade and sub-base in road constructions.

As the name suggests, these rollers have a cylindrical heavy steel surface consisting of a network of steel bars forming a grid with squire holes. The weight of this roller can be increased by ballasting with concrete blocks.

Typical weights vary between 5.5 tonnes net and 15 tonnes ballasted. Grid rollers provide high contact pressure but little kneading action and are suitable for compacting most coarse grained soils.

6. Pad Foot / Tamping Rollers:

These rollers are similar to sheepsfoot rollers with lugs of larger area than sheepsfoot rollers.

The static pad foot rollers also called tamping rollers have static weights in the range of 15 to 40 tonnes and their static linear drum loads are between 30 and 80 kg/cm. These rollers are more preferable than sheepsfoot roller due to their high production capacity, and they are replacing sheepsfoot rollers.

The degree of compaction achieved is more than sheepsfoot rollers. The density of soil achieved after compaction with this roller is more uniform.

These rollers operate at high speeds, and are capable to breaking large lumps. These rollers also consists of leveling blades to spread the material.

Pad foot or tamping rollers are best suitable for compacting cohesive soils.

4.grading and finishing equipment:

1.Grader:A grader, also commonly referred to as a road grader or a motor grader, is a construction machine with a long blade used to create a flat surface during the grading process. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third axle at the front end of the vehicle, with the blade in between. In certain countries, for example in Finland, almost every grader is equipped with a second blade that is placed in front of the front axle. Some construction personnel refer to the entire machine as "the blade". Capacities range from a blade width of 2.50 to 7.30 m and engines from 93–373 kW (125–500 hp). Certain graders can operate multiple attachments, or be used for separate tasks like underground mining.

In civil engineering, the grader's purpose is to "finish grade" (to refine or set precisely). The "rough grading" is performed by heavy equipment or engineering vehicles such as scrapers and bulldozers.

Graders are commonly used in the construction and maintenance of dirt roads and gravel roads. In the construction of paved roads they are used to prepare the base course to create a wide flat surface upon which to place the road surface. Graders are also used to set native soil foundation pads to finish grade prior to the construction of large buildings. Graders can produce inclined surfaces, to give cant (camber) to roads. In some countries they are used to produce drainage ditches with shallow V-shaped cross-sections on either side of highways.

Graders are multipurpose machines used for:

Finishing

Shaping bank

Sloping

Ditching

Grader’s primary purpose is cutting and moving material with a blade, known as moldboard.

Function:

To provide (shape) of soil surface to the desired grade.

limitations:

A grader is restricted to making shallow cuts in medium-hard materials

A grader should not be used for heavy excavations

A grader can move small amounts of material

A grader are capable of progressively cutting ditches to a depth of 3 ft.

So more economical to used other types of equipment to cut ditches deeper than 3 ft.

Components of Grader

• Moldboard (blade)

• Scarifier

• Light rear-mounted ripper

GRADER OPERATIONS

a. Planning Surface, used to plane or smooth off cut or fill surface

b. Ditch Cuts

c. Haul-road Maintenance

d. Spreading, often used to spread and mix dumped load.

TIME ESTIMATES

Formula Distance

(no.of passes x distance)/(speed x efficiency) = Time

Distance in miles

Speed in miles per hour

Time will be in hours

2.gradall:

The Gradall is a utility machine which combines the operating features of the hoe, dragline and motor grader.

3.trimmer:

Trimmers are specialty machines to fine finishing for special jobs.

In light-frame construction, a trimmer is a timber or metal beam (joist) used to create an opening around a stairwell, skylight, chimney, and the like. Trimmers are installed parallel to the primary floor or ceiling joists and support headers, which run perpendicular to the primary joists.

It can also refer to a jack stud that supports a header above a window or door opening.

The result is better accuracy and greater production compared to the fine-grading with a grader

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.