Earthwork Equipments in Construction

EARTHWORK EQUIPMENTS

Commercially wide ranges of excavating equipments are available in construction industry. It requires a much greater care and consideration in selecting the most suitable machine for a particular job. While selecting excavating equipment, the following factors should be considered.

❖ Nature of work

❖ Method of operation

❖ Duration of the job

❖ Machine specification

❖ Installation and operations costs

❖ Maintenance and spare costs

The different types of earthwork equipments are as follows:

(i) Excavators: Excavators are heavy construction equipment consisting of a boom, arm, bucket, and cab on a rotating superstructure atop an undercarriage with tracks or wheels. These machines are used mainly for digging purposes as well as various lifting and carrying tasks in various applications. All movement and functions of the excavator are accomplished through the use of hydraulic fluid, in addition with rams or motors. Based on their size and working type excavators are classified as follows:

* Compact Excavator: A compact or mini excavator is tracked or wheeled vehicle with an approximate operating weight from 0.7 to 7.5 tons. It generally includes a standard backfill blade and features independent boom swing. Hydraulic Excavators are somewhat different from other construction equipment in that all movement and functions of the machine are accomplished through the transfer of hydraulic fluid. The compact excavator's work group and blade are activated by hydraulic fluid acting upon hydraulic cylinders. The excavator's slew (rotation) and travel functions are also activated by hydraulic fluid powering hydraulic motors.

* Crawler Excavator: It is of two types namely mini and heavy crawler.

(a) Mini-Crawler Excavator: With a wide range of available sizes and features like Power tech engines, zero-tail-swing, offset boom, multiple attachments and ultra comfortable operator stations, there's mini excavator to fit every job. Hydraulic management system, which helps by balancing hydraulic pressure and flow and sensing when extra power is needed without draining other systems.

(b) Heavy Crawler Excavator: Crawler excavator gets the job done with muscle, control and peerless productivity. Efficient, cool-running engines and enhanced hydraulics make these the most-reliable and hardest-working excavators yet. Climb into one of these best-in-class cabs and unleash a mighty workhorse to tackle toughest jobs.

* Wheeled Excavators: Wheeled excavators easily navigate streets and hard surfaces to deliver powerful bucket forces in well-balanced, high-stability gritos bit machines. Even with all that muscle outside, operators find quiet comfort lovan brinside spacious air conditioned cabs. Low effort levers deliver smooth rolom boom and bucket control.

* Backhoe excavator: Backhoe excavator, also called a excavator and commonly shortened to backhoe, is a heavy equipment vehicle that consists of a tractor fitted with a shovel/bucket on the front and a small backhoe on the back. Due to its relatively small size and versatility, backhoe loaders are very common in urban engineering and small construction projects such as building a small house, fixing urban roads, etc., Backhoe deliver versatility and power in a cost-efficient package, whether placing pipe, busting up blacktop or digging deep. Each model features excavator-style boom, bucket and hydraulics. Crowd power, swing torque and boom and dipper stick lift are impressive and high pressure hydraulics are powerful and quick. Easy-to-operate controls smoothly blend functions.

* Dragline Excavator: Dragline Excavation Systems are heavy equipment used in civil engineering and surface mining. Smaller types are used for road and port construction. The larger types are used in striping operations to move overburden above coal, and for tar sand mining. Draglines are amongst the largest mobile equipment ever built on land, and weigh about 2000 metric tons, though specimens weighing up to 13,000 metric tons have also been constructed. A dragline bucket system consists of a large bucket which is suspended from a boom (a large truss like structure) with wire ropes. The bucket is maneuvered by means of a number of ropes and chains. The hoist rope, powered by large diesel or electric motors, supports the bucket and hoist coupler assembly from the boom. The dragrope is used to draw the bucket assembly horizontally. By skillful maneuver of the hoist and the dragropes the bucket is controlled for various operations.

* Long Reach Excavator: The long reach excavator or high reach excavator is a development of the excavator with an especially long boom arm, which is primarily used for demolition. Instead of excavating ditches, the long reach excavator is designed to reach the upper stories of buildings that are being demolished and pull down the structure in a controlled fashion. Today it has largely replaced the wrecking ball as the primary tool for demolition.

* Suction Excavator: A suction excavator or vacuum excavator is a construction vehicle that removes earth from a hole on land or removes heavy debris on land, from various places, by powerful suction through a wide suction pipe which is up to a foot or so diameter. The suction inlet air speed may be up to 100 meters/second. The suction nozzle may have two handles for a man to hold it by; those handles may be on a collar which can be rotated to uncover suction release openings (with grilles over) to release the suction to make the suction nozzle drop anything which it has picked up and is too big to go up the tube. The end of the tube may be toothed. This helps to cut earth when use for excavating; but when it is used to suck up loose debris and litter, some types of debris items may snag on the teeth. The earth to be sucked out may be loosened first with a compressed-air lance or a powerful water jet.

* Power Shovel: A power shovel is also known as stripping shovel or front shovel or electric mining shovel. It is a bucket equipped machine, usually electrically powered, used for digging and loading earth or fragmented rock and for mineral extraction.

(ii) Loaders: A foader is a heavy equipment machine often used in construction, to load materials such as excavated earth, sand, rock, gravel, asphalt, demolition debris, logs, raw minerals and recycled material into or onto another type of machinery such as a dump truck, conveyor belt, feed- hopper, or railcars. The loaders may be of the following types:

* Backhoe loaders are versatile instruments found on most construction sites. Their unique design allows for maximum efficiency, with these many defining features. The loading bucket at the front can suit a wide range of material handling applications. The buckets can be used to load, transport and dump materials quickly. Backhoes feature a hoe attachment on the back. These attachments are used to dig the materials directly. A hoe attachment has teeth that can make it easier to probe into the material and break it apart.

* Skid steer loaders are another useful loader type. Skid steers are excellent for light work and a fast-paced job site. These four-wheeled tools feature a unique movement design, allowing you to steer by skidding. During use, the operator locks one pair of tires and leaves the other side free. The action allows the machine to turn within a predefined radius. The specialized steering ability makes skid steer loaders ideal for tight spaces. All skid steers have tires instead of tracks. The difference between wheels and tracks comes down to speed against weight distribution. Tires let a skid steer move quickly but maintain a connection to the ground. On the other hand, tracks make machines slower, but they put less pressure on their work environment.

* Crawler loader combines the stability of the crawler tractor with the abilities of a wheel loader. However, to construct a reliable crawler loader it requires more than simply attaching a loader bucket onto a crawler tractor. It must be designed with its specific purpose in mind to ensure it has the strength to withstand heavy excavating. The introduction of hydraulic excavators diminished the market for the crawler loader because it was unable to match the excavator's lifting power and flexibility. However, crawler loaders are capable of maneuvering across the entire construction site under its own power, whereas most hydraulic excavators require towing or transport.

* Wheel loaders are excellent options for shoveling large volumes in a short time. These are perfect for loading jobs where machines need to wheel about and move materials. Wheel loaders also serve as multi-purpose machines, and there's an array of work attachments can be fit onto a wheel loader to immediately have it doing other work. Wheel loaders have the latest technology and built-in toughness to work in the most challenging applications. This may includes a variety of types, such as:

❖ Compact wheel loaders

❖ Small wheel loaders

❖ Medium wheel loaders

❖ Large wheel loaders

(iii) Scrapers: Scrapers are used for earth moving in construction, mining and agriculture industries and often is the plant hire machine of choice over vast areas and on levelling projects. They are used to remove layers of earth across a vast area of land. They typically have very large rubber tires and are often motorized, though some are tow-behind machines and allow you to quickly and easily move product around your site to get the job done When the scraper machine and it's attached trailer pass over an area of dirt to be removed, the operator drops a sharp horizontal blade located in the trailer, or otherwise known as the bowl, into the soil below. As the scraper machines moves forward, dirt is collected or scraped up into the bowl where it is then later collected when it becomes full. Scrapers may be classified as follows:

* Single Engine Wheeled Scrapers: The single-engine wheeled scraper is perhaps the most common type of scraper. It consists of a bowl, an apron that is drops over a load of earth for transport, and an ejector that relies on hydraulics to get rid of a load once you have successfully moved it. With hydraulics, each separate function can operate separately, as well, making these exceptionally versatile machines.

* Dual Engine Wheeled Scrapers: For terrains that are a little tougher than your average job site, the dual engine wheeled scraper machine would be required. This scraper machine Dual-engine wheeled scrapers are another bangin great option if you are hauling earth for a short distance. This type of evo solo scraper has two engines, with one controlling the front wheels and the other powering the rear. This style of scraper is also highly effective for short hauls and narrow cut-and-fill areas on job sites.

* Elevating Scrapers: Rather than rely on an apron like other scrapers, an elevating scraper uses an elevator that is either hydraulically or electrically driven. This elevator loads materials into a raised bowl that can then dump out a load by sliding the bowl's floor backwards, with the elevator capable of being reversed to help evenly and completely finish an offload.

* Pull Type Scrapers: Finally, pull-type scrapers are not motorized at all. Instead, these are towed behind other machines on site, but offer the advantage of being more capable of operating in wet, soft and sandy conditions. By not having its own driving capabilities, this can also make it easier to keep from getting stuck in messy terrain, which means the pull- type can be quite useful in rainy climates and springtime weather.

(iv) Graders: A grader, also commonly referred to as a road grader, a blade, a maintainer, or a motor grader, is a construction machine with a long blade used to create a flat surface. Graders are commonly used in the construction and maintenance of dirt roads and gravel roads. They are used to prepare the base course and to create a wide flat surface for the asphalt to be placed on. Graders are also used to set native soil foundation pads to finish grade prior to the construction of large buildings. 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.

Motor graders are classified depending on the arrangement of their frame. There are two types of categories graders can fall under: Rigid frame motor grader and Articulated frame motor grader. Today, most graders manufactured are articulated frame graders. This is as they are more useful in smaller construction spaces where there is less room to move or turn around. Small motor graders are perfect for landscaping jobs, road maintenance and other tasks that need to be completed in a tight space, whereas large motor graders are typically used for larger scale projects, such as highways and motorway construction.

(v) Dozers: Bulldozers are strong machines that mainly assist with pushing, digging, excavating, and leveling materials like soil and debris at a work bob site. They come with large, heavy blades with which soil is scraped and pushed. Some come with other modifications like rippers in the rear to help break down tough ground.

Different bulldozer blades serve different purposes, and can handle different types of materials and can handle a range of load weights.

* Straight Blades (S-Blade): An S-blade is the shortest type of blade a dozer can use and does not have side wings. This blade attaches to the arm in the lower back corners of the blade. Thanks to its shape, the straight blade is best for fine-grained and medium- to hard-density materials. The drawback is that its straight shape limits the dozer's lifting and carrying capabilities. Some of the best tasks for s-blades include stumping, back-filling, grading and evening soil.

* Angle Blade: This type of blade attaches to the center of the bulldozer's panel. Its location is useful for moving debris to the side since it can angle close to 30 degrees left or right. Due to this, an angle blade is considered a two-way blade. It's a great choice for projects involving soft- to medium- hard-density soils, snow, and gravel. Some of the best tasks for angle blades include stumping, shaping, stripping and ditching.

* Universal Blade (U-Blade): A U-blade has large side wings and a curved shape that makes it ideal for pushing materials across long stretches of land. The wings keep material from spilling over when in motion. Like S- Blades, they also attach to the lower back corners of the blade. It's the www.largest blade type in both height and width and is best used with soft- to medium-density soil. Some of the best tasks for u-blades include ditching, hauling, pushing and crowning.

* S-U (Semi-U) Blade: This blade combines features from the S-blade and the U-blade to give it stronger penetration and better overall versatility and is also known as cushion blade. It's narrower, less curved, and its side wings are smaller compared to a normal U-blade. This design makes it ideal for pushing soil across long distances. It's best used to push soft- to medium-density sand and soil. Some of the best tasks for an s-u blade include crowning, moving heavy material, stumping and ditching.

There are many different bulldozer types to choose from depending on terrain, project type, and similar other criteria. Types of bulldozers are as follows:

* Crawler Bulldozer: A crawler is sometimes referred to as a track bulldozer and looks most similar to a tractor. This heavyweight is great for moving heavy materials from one area to another. This bulldozer is ideal for traversing dense and irregular terrain since the tracks give it great traction. Larger crawlers have rippers that assist with crushing and clearing dense terrain.

* Wheel Bulldozer: This machine is sometimes referred to as a tire bulldozer and is normally larger than a crawler. A wheel dozer is more maneuverable than a crawler since its tires offer better overall handling. It also has completely articulated hydraulic steering and moves on a smaller axis. This machine is also ideal to use for soft or sensitive ground since the tires are gentler than tracks.

* Mini Bulldozer: This smaller bulldozer is also known as a compact bulldozer. A mini dozer is great for projects that require more maneuverability and versatility than larger machinery. Thanks to its small size, a compact bulldozer can perform well in different types of projects that require tasks like grading and clearing lots.

(vi)Trenchers: Trenchers or ditchers are similar to excavators in the sense that they penetrate the earth, breaking soil and rock, and remove it from the ground. Trenchers are heavy machines designed for excavating. They have a metal chain with teeth made of high-strength steel. This allows the machine to tear into the ground, lifting and moving massive amounts of earth. Because of the sheer size and strength of the machine, trenchers are capable of tearing through heavy tree root systems and densely packed earth. An excavator produces a ditch that is significantly wider at the top than the bottom, leaving you with a lot of backfill to deal with. But a trencher produces exactly what the name implies, a clean trench with a flat bottom and smooth walls. Trenchers come in three types as follows:

* Chain trenchers: Chain trenchers have a chainsaw-like design. They use a digging belt or chain to cut into the ground. Due to their flexibility, chain trenchers can cut narrow and deep trenches for utility companies.

* Wheel trenchers: Wheel trenchers, also called rockwheels, have a toothed metal wheel that can be used for hard or soft soils. Wheel trenchers work best in areas where there are many rock formations.

* Micro trenchers: Micro trenchers are used for cutting "micro trenches". These are micro ones with dimensions significantly smaller than those cut by conventional trenchers ranging from 0.5 to 2 inches wide and around 2 feet in depth.