- February 28, 2019
- Posted by: khawaja senan
- Category: Heavy Equipment
The execution of the work of a road entails in any case a series of processes of clearing, embankment and excavation to adapt the levels of the natural terrain to those required by the construction project. In this post we collect the different types of machinery used to carry out these tasks in its different phases.
The main function of the excavating machines is the extraction of material from the natural terrain, its loading and transport and its unloading in the chosen place for the realization of the collection. Depending on the characteristics and unevenness of the terrain, two different types of excavators are used: on wheels and on chains or caterpillars. The second ones offer greater stability in the face of significant uneven terrain, since the center of gravity of the machine is located at a lower height and also has a greater area of contact with the ground.
The extraction of material from the ground can be done in various ways, depending on the nature of the terrain, its composition and resistance to cutting . Specialized work tools are required for this:
- Bucket: used to directly dig the material to be excavated or to load and transport it to other areas. It is used in granular or low resistance fields . It is the most common extraction tool.
- Hammer: used to break rock-like terrains or formed by materials of great hardness in small fragments that can later be handled by other machinery.
- Ripper: it is generally used for the breaking of hard surface layers , which can not be fragmented by other means.
The loader is used in the excavation and clearing for the collection and transport of the material collected by the excavator, or generated by blasting the ground to the place chosen for on-site storage, or to the means of transport that will later transfer it to the quarry. The material transported by the shovel in these tasks is mainly composed of rocks, conglomerates and lands. The shovel bucket must adapt to the characteristics of the materials that must be transported.
The bulldozer tractor is used in the work of clearing and excavation as an alternative to the excavator for the extraction and transport of thin layers of soil as long as the depth of excavation is small. These extended layers must be subsequently compacted by roller. With respect to the execution of embankments, the bulldozer can also be used for the extended piles of filler material, although there are more specialized equipment for carrying out this task, such as the motor grader, of which we will speak later. The main advantage presented by bulldozers against loaders is that they can perform excavation and hauling without the need to add auxiliary equipment.
The scrapers are machinery used specifically for the loading and transport of material. The scrapers can perform excavation and hauling tasks similar to those of the bulldozers, but they can not carry out the extension of material loads. Its activity is indicated for the extraction of land from superficial layers of easily excavated materials, collection of material and subsequent dumping in the place indicated for it. They are suitable equipment for the excavation of large surfaces and shallow depth.
The motor grader is a widely used instrument in the earthwork phase. It is responsible for extending and leveling the layers of material that make up the successive layers of an embankment. The lower central blade of the motor grader is called mouldboard and is responsible for the extension and leveling, being able to ascend, descend, rotate and swing to get the desired effect on the leveling layer. The leveling of slopes is also usually carried out by means of a motor grader, whether these are dismounted or embankment.
The motor grader can be equipped with various tools, such as:
- Front dozer blade: it is a leaf located in the front that serves to push the excess material , leaving only the amount needed for leveling the extended layer.
- Central scarifier: it is a toothed element that is located in front of the moldboard, whose function is the removal of roots and stones from the ground to facilitate its handling.
- Rear ripper: its function is similar to that of the scarifier, but it covers a wider work surface.
Once a new placement field is extended and leveled, it must be compacted in order to provide the necessary bearing capacity for the reception of the loads generated by the weight of the structure of the track (static charges), as well as traffic. that it circulates (dynamic loads).
For this purpose the roller compactor is used, it is a machine that contains a vibrating roller that transfers to the ground a static load, provided by the own weight of the machine, and a dynamic load by means of an eccentric mass that rotates around the Roller shaft producing a vibration. There are two types of main roller compactor:
- Smooth roller : for use in granular compositions.
- Goat’s foot : for use in cohesive terrain.
For its part, the means of transport of material to landfill, quarry or area of internal collection to the work itself are very varied and depend on the characteristics of the land in which it works, as well as the geometrical characteristics of the work itself, being the best known are the rigid dumper, the articulated dump truck.