Swiss N2 Motorway tunnel restoration

Entrance portal of the Vedeggio-Cassarate tunnel, at the Lugano Nord exit of the N2 motorway

Over the past three decades Drytech has carried out several tunnel restoration projects on the Swiss N2 Motorway: the main artery crossing the country in a north-south direction, from Basel to Chiasso.

The restoration system, based on expanding resin injections, sealed the seepages in cracks, joints and gravel nests.

Among others, Drytech has rehabilitated tunnels:

N2 Arisdorf tunnel – cracks, joints and gravel nests;

N2 Belchen tunnel, Dichten – passages, cracks and gravel nests;

N2 Hagnau Tunnel, Muttenz – passages and associated structures;

N2 Pratteln Tunnel, Liestal Schönthal – cracks, wall and ceiling joints;

N2 Lange Heid Tunnel, Münchenstein – movement joints;

N2 Dosso Taverne Tunnel – recess joints;

N2 Melide Grancia Tunnel – cracks and joints in the technical tunnel;

N2 Galleria Melide Grancia – cracks and joints in the summit part of the vault;

In addition, Drytech restored the portal of the Vedeggio Cassarate tunnel by sealing cracks.

Renovation with Ex-Post Drytech Tank, Italy

Due to a faulty geological survey, no provision was made for waterproofing the basement of this prestigious residential complex, which was rehabilitated by constructing a Ex-post Drytech Tank.

Due to a faulty geological survey, no provision was made for waterproofing the basement of this prestigious residential complex, which was rehabilitated by constructing a Ex-post Drytech Tank.

Unfortunately, after the construction was completed, a peak of the seasonal water table flooded the -2 level, making the garages unusable.

At this point Drytech was involved to restore the underground.

The analysis of the structural and environmental situation by the Engineering has identified the best solution in the construction of a Ex-post Drytech Tank.

The industrial floor built above the gravel filling was therefore demolished. The water table was brought under control with a well-point system.

We then proceeded to lay the cracking elements in the stalls and prepare the stalls / walls and stalls / columns joints with the DRYset Channel.

The numerous crossings produced by the well-points have also been suitably prepared for the waterproofing injection, once the concrete has matured.

The new waterproof concrete slab based on the Drytech recipe was then cast.

To ensure the height of the extrados, it was necessary to create the sealed platform and the industrial floor in a single fresh-on-fresh helicopter jet.

When the concrete has matured, Drytech has perfected the injection of programmed cracks, joints and crossings with DRYflex expansive resin.

Due to its elastic quality, the resin is re-injectable, so it guarantees the possibility of maintaining the system over the years.

The construction of the ex-post Drytech platform made it possible to waterproof the basements and to deliver the properties with the usable garages.

Restoration Project: Drytech Engineering

Waterproofing: Drytech Italy

Drytech Ex-Post tank for oil plant, Italy

To protect the ground from leaks in an oil valve park, Drytech built a watertight tank underneath the plant without interrupting its operations.

To protect the ground from leaks in an oil valve park, Drytech built a watertight tank underneath the plant without interrupting its operations.

A valve park sorts the crude oil unloaded from tankers to storage tanks.

In the specific case of the plant’s leaks in the ground, it was necessary and urgent to restore it, but without the possibility of interrupting its activity.

It was therefore decided to create an impermeable tank below the system of valves, which had been placed in contact with the ground.

With an almost archaeological approach, the ground beneath the plant was excavated by gradually inserting supports to the pipelines.

Then we proceeded to the casting of the drytech waterproof concrete slab and walls and, when the casting was ripe, the waterproofing injection of DRYflex resin in the programmed cracks, in the construction joints and in the crossings, including the pipe supports, which were left in place.

The intervention, designed and coordinated by Drytech Engineering, restored the system to safety and made it definitively accessible for maintenance.

Waterproofing: Drytech Italia, Como

Ex-post Drytech Tank: 4’000 m²

Vetropack water tower, Corsico

Drytech restored the water tower of the Vetropack plant in Corsico with injections of waterproofing resin carried out from the outside, without having to empty the barrel

Drytech restored the water tower of the Vetropack plant in Corsico with injections of waterproofing resin carried out from the outside, without having to empty the barrel.

The fire-fighting water reserve was thus guaranteed to the continuous-cycle industrial plants and the company did not have to rent a tanker for the fire brigade.

With the Drytech system it is no longer necessary to dive into the barrels, with all the related logistical and safety implications.

For the intervention, Drytech technicians exploited a scaffolding already set up by a company to restore the external surface of the tower.

Normally the Drytech Rehabilitation System allows the practical use of aerial platforms, with a consequent saving on costs and time for setting up the scaffold.

Client: Vetropack, Corsico

Restoration: Drytech Italia, Como

Algiers subway restoration

Drytech technicians prepare for the waterproofing renovation of 5 tunnels and 5 metro stations in Algiers

Drytech restored the waterproofing of 5 tunnels and 5 stations of the Algiers metro, sealing over 4 km of underground tunnels.

The proximity to the sea exposes the structure to a water table of 6-8 meters.

During the construction phase, various systems were used to waterproof tunnels and stations, but none of these managed to guarantee 100% waterproofness.

Hence the need for definitive reorganization. The Algerian Ministry of Transport has commissioned the Eurometro company – London consultants specialized in the subway sector – to identify a solution to the problem of infiltrations.

After a worldwide survey, Eurometro proposed the Drytech Restoration System, based on injections from the inside of the DRYflex acrylic resin structure.

The Line 1 tunnel is made up of 10 meters long waterproof concrete segments, connected by 2 recovery joints interspersed with an anti-seismic movement joint.

Waterstop tapes were inserted into the joints, which only worked in 45% of the joints.

The joints of the adjacent structures, of the stations, of the ventilation ducts etc., were instead waterproofed with bentonite expansive profiles, the expansion of which however proved to be limited compared to the shrinkage of the concrete.

Even the jet shots at the air intakes showed infiltrations.

The thermal changes to which they are naturally exposed produce structural movements that split the polyurethane used to waterproof them.

Polyurethane, in fact, being semi-rigid and adhesive, undergoes the movements of the structure and, when they are particularly large, it cracks or loses adhesion.

Finally, shrinkage cracks were produced in the concrete which represented as many points of permeability of the structure.

The Drytech rehabilitation intervention for the waterproofing of the Algiers Metro was cataloged with the REAL system of Sir of Turin.

The application creates a virtual reconstruction of the structure, with all the information relating to the remediation intervention.

An X-ray that allows a quick and interactive consultation of images and data relating to the individual interventions performed.

Railway underpass, Albairate

DRYflex resin injections to waterproof a road subway, without having to interrupt the upper railway traffic.

A waterproof underpass without having to interrupt the upper railway traffic.

The renovation of the Albairate road underpass was necessary due to the failure of the existing bentonite system.

The structure was restored with DRYflex resin injections in the movement joints and in the casting joints.

The underpass began to leak a few months after opening.

Drytech intervened from inside the building, without structural demolitions or external excavations and, above all, without limitations to the normal circulation of trains on the Milan-Vigevano line.

Like any Drytech renovation, this too allowed immediate verification.

Ownership: RFI Rete Ferroviaria Italiana

Restoration project: Ing. Maurizio Schiavo, Padova

Restoration company: D’Adiutorio Appalti e Costruzioni Srl, Montorio al Vomano

Drytech restoration:
277 m movement joints;
133 m joints.