Special civil engineering of the Volken Group

We get to the bottom of every issue

The Volken Group is also a strong and reliable partner in specialist civil engineering. We cover the entire range of this specialist field - with drilling and anchoring of all kinds, or with pile and shotcrete walls, right up to securing excavations. This benefits private individuals and companies and public clients such as railway companies.

With us, you stay on the safe side

No matter how complex or challenging your construction project is, the Volken Group accompanies you from planning and scheduling to logistics and execution. We work from A to Z in a customer-oriented manner, always on schedule and all-around cost-conscious. Even in difficult terrain to access or deep in the mountains, our teams provide first-class services with durability - thanks to years of experience, state-of-the-art equipment, and a wide range of construction technologies.

Crawler crane on the walking excavator

Even where fox and hare say good night to each other, the Volken Group is at home in foundation engineering. For example, the manoeuvrable walking excavator is also known as a spider excavator. A drilling mount is mounted on it and positioned at the desired location. The mast has independent controls and drills micropiles as well as nail walls.

The helicopter jumps in

Walking excavators reach many places, but not all. The self-propelled machine "Voyager" from Marini is used everywhere. It can be dismantled, flown to the construction site on the helicopter, and assembled directly by it. The drill is ready for use within half a day. We use it primarily for micropile work, such as is found in the construction of mast or bridge foundations.


The self-propelled drilling machine

Because it is neither mounted nor fixed to an excavator, it can move freely and be operated by just one worker. We mainly drill prestressed anchors with this special machine.


The largest drilling machine

This powerful drilling machine weighs 24 tonnes and drills strand anchors and bored piles with diameters of up to 300 mm. Despite its size, the machine is very flexible: the drill head can be turned in almost any direction and can work vertically as well as horizontally.

Only together can you go deep

Special civil engineering is always teamwork that has to be well coordinated. The drilling machine operator could not carry out a project alone, so several construction workers were at his side. They help him with the installation or with extending the bored piles. It's a tough and strenuous job that requires muscular strength and stamina.

What is shotcrete?

Shotcrete is used to seal and support vertical or sloping excavation surfaces. It is used to secure excavation pits or slopes and in tunnel construction. It arrives at the installation site via a hose line and is applied pneumatically by the spray nozzle. This creates impact energy that compacts it. There are basically two methods for placing shotcrete. In the dry spraying method, the concrete mix is conveyed to the spraying nozzle and only there mixed with water and applied. In this way, even large distances can be bridged. The already mixed components are pumped to the spraying nozzle in the wet spraying method. This achieves a more uniform quality and enables more rapid work.

Always at the right angle, even in narrow galleries

With our concrete spraying system on caterpillars, projects can be implemented mechanically. Shotcrete from this machine can be placed at the same spraying angle at any height. By hand, you would have to spray all the concrete from the bottom to the top. With an optimal spraying angle, however, concrete adheres better. Less material is lost because less bounces off and falls to the ground. In addition, the machine can be operated by radio control. This means that workers do not get too close to the machine and are better protected even where space is limited - for example, underground in narrow tunnels or at heights of up to 8.75 metres, which we reach with an extendable spray arm.

Safety for people and the environment

Building pit closures are becoming more important and are standard at the Volken Group. Especially in cities, where construction is becoming increasingly dense or on slopes on unsafe building ground. We adapt the excavation pit protections individually to the requirements, and we offer conventional nail walls or micropile walls.

Micropiles for more load-bearing capacity

Load-bearing geology is not found everywhere, especially where foundations for bridges and towers are being built. For such projects, we can meet special requirements regarding given space conditions. With our drilling rigs, we can construct cased as well as directly injected micropiles.

Micropiles are piles with a diameter of up to 30 cm. The main function of micropiles is to transfer compressive as well as tensile loads into the deeper and more load-bearing strata. Micropiles can be drilled as overburden boreholes or displacement boreholes. In stable soils, uncased micropiles are drilled destructively.


Anchors and nails

Our machinery enables us to offer a wide range of anchor work. The range extends from untensioned temporary and permanent bar anchors, through injection drilled anchors, to prestressed temporary as well as permanent strand anchors.


Slope stabilisation

Every slope has its own characteristics. Loose slopes next to roads require different stabilisation than a rocky section. For example, unstable terrain can be stabilised with nailed nets or shotcrete walls. In foundation engineering, the geologist or engineer in charge usually decides which method to use.



Grouting consolidate the soil when there are holes in the subsoil by filling its gaps and cliffs. They are either used as a single measure or to stabilise the terrain at depth before drilling. For ground improvement measures, we can also offer multi-stage grouting.

The ears also drill, just like the feeling

No one can foresee everything that awaits him in the subsoil, and you can only guess or feel it. That is why our employees are not only trained accordingly; they also have a great feeling for the drilling equipment and the soil material. Depending on how the drill behaves and sounds, the machine operator has to slow down, back off a bit, free the borehole or tilt the drill head slightly. However, this fine feeling only comes with time and requires several years of experience.


The challenge of the Kipferwald construction site

This section of the Matterhorn-Gotthard railway between Stalden and St. Niklaus stands on a slippery slope. Over the years, the slope forces have pushed the existing wall too close to the tracks. The distance between trains and the retaining wall became smaller and smaller. Therefore, the narrow track was widened, and the old retaining wall was tied to the slope with strand anchors. Now it can slide along with the slope. Normally, strand anchors are anchored in stable, solid terrain, but the ground is very unstable here. This task was also a real challenge for the Volken Group and its machinists: 172 strand anchors had to be installed in loose, waterlogged material. After heavy rainfall, we often drilled into large amounts of water. Or we drilled into the void but encountered mighty rocks at a depth that shook the entire drilling rig. Excellent drilling specialists can only master such projects under difficult conditions.

Help from the air

Drilling rigs only work with power units and compressors, and they also need heaps of cement and lots of water to anchor them. Where there is no other way, these materials and machines are flown to the construction site by helicopter. Depending on the helicopter model and altitude, this requires several flights with loads weighing 800 to 900 kg. Thoughtful planning is essential here because later air transport for machines or tools left behind would be very expensive.

Helicopters can also concrete

In addition to logistics, helicopters also help with concrete work. To do this, they hang the concrete in smaller buckets and bring it in that way. For one cubic metre of building material, three rotations are necessary. A delicate task, because bad weather or strong winds can interrupt the work at any time.

Benefits with the Volken Group

A contact person

Whether it be excavation support, shell construction, or scaffolding, a contact person will be there to assist you.

Modern machinery

We use the newest machines and happily take advantage of high tech.

Proven specialists

Whether it be structural or civil engineering, hydraulic engineering or scaffolding, our specialists are masters of their trade.

Contact persons

Adem Salihi

Department Manager Foundation Engineering

+41 79 755 23 92

+41 27 948 05 48


Erhard Burgener

Head of Civil Engineering
Member of the Executive Board

+41 79 744 68 16

+41 27 948 05 48


Stefan Volken

Member of the management

+41 79 658 63 33

+41 27 948 05 05