As the requests for intervention for
maintenance, renovation and restoration of road tunnels increase, Simex has strengthened its range of MP cutter heads for profiling with a
special model created for big prime movers with specific characteristics. We are talking about the
MP 1000HD, where the acronym HD stands for "heavy duty", to indicate heavy and demanding jobs.
The MP 1000HD cutter head was created for the specific project of removing damaged surfaces in tunnels on behalf of
Amplia Infrastructures, formerly Pavimental, a subsidiary of Autostrade per l'Italia, a company specialized in the construction and maintenance of motorway civil works and plant engineering.
Designed for
excavators from 35 to 60 tons customized for tunneling, the HD version differs from the MP model of the same width due to several operational characteristics:
- Piston motors in direct drive with the drum which release a hydraulic power of 200 kW and a cutting force of 65 kN
- Hydraulic depth adjustment up to 150 mm via side wheels
- Independent depth adjustment on RH and LH wheels to easily make side-by-side passes
- Hydraulic wall alignment device
- 360° hydraulic rotation
- Nebulizer kit for enhanced dust suppression
The MP 1000HD is a special piece of equipment, with an
operating weight of over 4000 kg, which requires a dedicated excavator, with high hydraulic capacity, to be able to perform on tunnel vaults. For the construction site commissioned by Amplia Infrastructures, the remote-control operating machine was created by
Laurini Officine Meccaniche of Busseto, Italy, with the name "Jocker", which stands out for an innovative telescopic arm that allows the entire profile of the tunnel to be milled in a single pass, for a width of 240°. The next pass, in the opposite direction, will be made advancing only with the tracks, without interrupting the work on the vault to reposition the prime mover.
MP 1000HD: a special cutter head to increase performance in tunnel maintenance
Simex MP 1000HD cutter head for profiling was used
to remove the deteriorated layers of concrete inside the several tunnels that characterize the stretch of A1 motorway, towards Florence. The
depth and uniformity of the scarification are hydraulically granted thanks to the independently controlled side wheels, and by the hydraulically adjustable attachment - both
controlled remotely by the operator – for profiling the tunnel lining from the ground, along the side walls, up to the crown, with controlled descent on the other side.
In tunnels there was widespread deterioration of the lining concrete, with cracks and gravel pockets that arise due to numerous infiltrations of water. The unavoidable
deterioration of concrete requires a remediation and refurbishing intervention. In the driest points, where the problem was linked only to concrete deterioration, the scarification was 5 cm. Up to 10 cm in those areas where water infiltrations were found. The subsequent restoration takes into account the previous damage: after scarifying dry surfaces proceeding with grout restoration will be enough, while in the presence of infiltrations it will be necessary to install draining membranes in order to convey excess water into special channels.
MP 1000 is a completely new piece of equipment on the market with simplified operation which leads to a reduction in the delivery time of the work, which in the infrastructure sector is crucial for the profitability on the industry.
Concluding the milling activities earlier not only allows to avoid penalties but also anticipates subsequent operations such as restoration with grout, the installation of ribs, drainage membranes or cables and pipes.