Looking for what are micropiles used for? Then here you will find in detail information about micropile uses.
Also, In this article we are going to describe the procedures that are necessary for the execution and the respective control of the foundations with micropiles, that is, from the moment the machinery is located on the job site until the moment the work is finished.
Micropiles definition
Micropiles are defined as one of the different elements that can be used in a foundation, they are resistant to compression and traction forces; They consist of a steel tube that is placed inside the hole made by a piling machine and is complemented with a cement grout that can be supplied by injection.
When to use micropiles?
Micropiles are used when the surface layers or strata of the ground do not have sufficient bearing capacity to absorb the loads transmitted by some type of structure.
What Are Micropiles Used For?
You should know that the bearing capacity that micropiles have is lower compared to that of conventional piles . Thanks to this, micropiles are used in lands where it is not possible to execute piles, either due to the presence of difficult access or any other cause that prevents it.
Cases in which the micropile system is used the most:
Micropiles are very useful in different types of constructions, among the most outstanding are the following.
- To reinforce foundations in the expansion of buildings.
- When it is necessary to underline buildings.
- At the time it is necessary to make a deep foundation in projects that have small dimensions and with difficult access.
- For the support and reinforcement of existing foundations for the excavation of basements.
- At the time that a deep foundation is required in properties that have terrain not suitable for the implementation of conventional piles.
Use of micropiles for new foundations
The use of micropiles for new foundations can occur in the different situations that we will mention below.
To cement a structure that has adjoining structures
If it is necessary to make a new foundation, but there are adjoining structures on the property, the most recommended is the use of micropiles in order to avoid the following situations.
- Vibrations.
- The strong knocking that a large equipment can generate.
- Extensive excavations without tubing.
- The access of old and large machines to cement.
For the realization of screens with micropiles
The use of micropiles in the realization of sheeting can be given by the following conditions.
- In order to achieve an excavation to a certain depth without felling.
- When it is necessary to underpin neighboring structures.
They should also be used in the case that the traditional continuous screen or with large diameter piles is not possible to perform.
Use of micropiles to reinforce existing foundations
The use of micropiles for the reinforcement of existing foundations can be presented by the following cases.
- Due to the increased loads on the existing foundation
- Thanks to the construction of new structures that cannot gravitate on the same foundation.
- When modifying the existing structure.
- For the seating of structures
That is, buildings, industrial warehouses, monuments, bridges, viaducts, which, due to failures in the foundations of the land where their foundations are located, run the risk of suffering some alteration.
What are the tasks prior to the completion of the micropiles?
There are several tasks prior to the realization of the micropiles, these will be mentioned below.
It is very important to know the report of the soil study
Once you have the soil study report, you should make sure that it determines the following aspects.
- The stratigraphic section and the level of the water table.
- The mechanical characteristics of the terrain.
- The determination of the depth that is estimated for the foundation.
- The degree of aggressiveness that the terrain has.
All this is important to know to know what type of terrain you face and what drilling equipment you should use.
Prepare the surface
To prepare the seating surface, you must previously carry out earthworks, cleaning of obstacles and organic material. All this in order to obtain sufficient width and length to allow the drilling equipment to be adequately maneuvered.
Inspection of neighboring buildings
The inspection of the neighboring buildings is carried out in order to identify the services that may affect the performance of the works, once identified, if they exist, the necessary shifting or replacement must be carried out.
What is location and stakeout
The location and stakeout for the micropiles has to do with marking the point where they should be located, this is done with wooden stakes with a wire at the tip.
Once the terrain and the center of the pile have been marked, the references should be taken with the four cardinal points, with a prudent distance to maintain the center of the pile during execution.
Micropiles construction process
The construction process of micropiles comprises several steps that we will mention below.
Cleaning and drilling
Once the stakeout of the micropiles has been carried out, the drilling work begins by placing the drilling equipment right in the center of the micropile; it is very important that the tower or boom be plumb before drilling the ground by means of rotation.
Auger diameter for micropile
The diameter of the bit for the micropile is established taking into account the specifications of the project drawings. The bit handles drilling using compound twist and drop movements. The machine operator is the one in charge of controlling the pressure required for drilling depending on the strata, harder or softer, that he encounters on the ground.
