Foundation reinforcement

New ground engineering hammer, tested in Södertälje Canal, Sweden

Wassara´s new hammer developed specifically for Ground Engineering was tested in a casing advancement application during dredging works for widening ...


Södertälje, Sweden


Züblin Scandinavia AB

Type of product

W120.G3 Hammer

Wassara´s new hammer developed specifically for Ground Engineering was tested in a casing advancement application during dredging works for widening of the Södertälje canal in co-operation with Züblin Scandinavia AB.

Challenge / Solution

The expansion of the existing canal lock chamber in Södertälje includes the construction of two new lock-gates. Such work typically entails ground stabilization activities such as anchoring and jet-grouting.

Ground conditions present were typical for Swedish esker with highly variable conditions and layers of singular grain sizes and boulders. In addition, in some areas there were residual materials left during the construction of the existing lock. This meant that any boreholes couldn’t be left open without any kind of wall reinforcement. The solution was to advance casing to the required depth until time came for the next stage of either jet-grouting or anchoring.

The Wassara approach was the preferred method used due to the formation being water drenched and consisting of high permeability layers.

Project size

The so-called ‘Mälarprojektet – del Södertälje Kanal och Sluss’ is a large infrastructure project aimed at increasing the existing canal capacity both by enlarging the lock chamber and widening of the sailable segment. LKAB Wassara were involved in the project works between April and September 2018.

Construction program

The new W120.G3 hammer performance was approved by the drilling personnel on site. After 2 500m of drilling (see picture to the right), the hammer was refitted with new seals while most other moving parts were still in great condition.

The larger piston did not show any signs of impact deformation which was otherwise present on the standard W120 due to air-DTH bits (adapted for Wassara drilling) being used.

Furthermore, the hammer had an increased water flow which was a positive aspect from the drillers point of view as cuttings were removed more efficiently.

Download full Casestudy for further technical details

Equipment used

DTH HammerWassara W120.G3
Casing systemMaxbit Mitsubishi
PumpHammelman HDP 122-326
Casing168.3 OD mm
Bore hole length~30 m
Scope of drilling2 500 m
Drilling formationEsker, stratified sands, gravel and large
stones (up to 1.5m in diameter), solid rock
Project yearApril 2018 – September 2018

Case studies

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