Aplicaciones en tierra

Compactación en pendiente

La compactación en pendientes es a menudo requerida en la construcción de presas y canales. Las presas con superficies ascendentes impermeables de hormigón ó asfalto es un buen ejemplo donde se requiere la compactación en pendiente. Un rodillo monocilíndrico vibrante autopropulsado es el tipo de maquina adecuada para este tipo de compactación . Si el rodillo necesita ser ayudado con un cabrestante ó no , depende de la inclinación. Cuando se compacta , la vibración debe conectarse en la subida y desconectarse en la bajada. Si el rodillo es ayudado por un cabrestante debe ser utilizado un asidero de protección para el operador. Un cable de seguridad debe ser también acoplado por si se rompe el cable del cabrestante . Siempre utilice un rodillo con sistema de protección ROPS y asegúrese que el operador utiliza el cinturón del asiento y el casco. Antes de utilizar una máquina en una pendiente empinada compruebe con el fabricante si se puede operar continuamente con esa inclinación.

Vibración del terreno

La transmisión de las vibraciones al terreno durante la compactación vibrante dependen de principalmente del tamaño del rodillo , de la amplitud y del material que está siendo compactado. Si existe un riesgo de dañar los edificios cercanos , debe inspeccionarse la existencia de grietas u otros daños antes de realizar los trabajos de compactación . Es siempre muy difícil probar las causas de ciertos daños después que la compactación se ha efectuado . Las vibraciones pueden ser sentidas por las personas y notadas en edificios bastante antes de alcanzar los niveles donde los daños se puedan producir. Esta es la razón de por qué muchos propietarios trataran de culpar a la compactación vibratoria de daños que ya existían anteriormente. Las siguientes reglas pueden ser utilizadas para calcular la distancia de seguridad para rodillos vibrantes:

Disclaimer: The above guidelines are offered as an indication of safe distances. Dynapac does not guarantee the safety of surrounding buildings and cannot be held responsible in any way if damage occurs when working according to the guidelines.

Confined areas/trench compaction

Safety is a main concern when working in confined areas and trenches. The risk of inhaling exhaust fumes and the risk of being hit by a machine is bigger if you are working in a tight area. Using remote controlled machines will free the operator from many of the dangers associated with this kind of work including that of collapsing trench walls etc.

Compaction over pipes and culverts (protective layers) It is necessary to have a certain layer thickness over pipes, culverts and other structures in the ground to avoid damaging them during compaction. The following values are recommended layer thickness. DISCLAIMER!!!

Dry compaction

Most soils are normally most effectively compacted at the optimum water content. However, in some areas such as arid or semi-arid areas it may be impractical or too costly to water the soil. In such cases, gravel and sand, can be compacted in a dry state (water content <1-2 %). It is important to take the saline content of the soil into account. High salt content may affect the final properties of the soil. Dry compaction has been applied on relatively thick layers in road and airfield applications in desert areas.

Deep compaction

Thick layers of water saturated sand or gravel with a fine content less than 5-10 % can be compacted in relatively thick layers with vibratory rollers. This can be used for compaction of dredged sand in land reclamation projects from the water level and up. The table below indicates the compaction depth for some different machine types.

Continuous compaction control (CCC)

The only way to get full coverage of the compaction results on a certain job is to use the roller as a measuring device. A vibratory roller can be used to measure the stiffness of the compacted material and the stiffness is a very good indicator of the compaction of a granular material. The roller measures and records the stiffness values at the same time as it is compacting the material. This will give the operator information of the level of compaction of different areas of the job site well as an indication of the level of homogeneity of the compaction. Using CCC early in the compaction process can locate weak areas that can be corrected before the project has progressed too far. This can lead to substatial savings compared to having to correct failures later in the project. Dynapac can provide a Compaction Meter on all single drum rollers and the possibility of adding a computer for continuous documentation of the compaction results. It is also possible to use satellite positioning to accurately locate the roller on the jobsite.

The influence of water content

Lack of or excess water is equally bad for the compaction performance in almost any soil material. Every material has a water content where the compaction is most efficient (Optimum water content) If the actual water content deviates from the optimum it means that extra passes are required to reach the compaction requirements or that the layer thickness must be decreased.