Placement of up to 1,200 t of clay-sand mixture per day – when the weather held out
The core element of the landfill liner is the four layers of clay with an overall thickness of 100 cm. Wachenfeld brought in truckloads of this material, a mixture of clay and sand, from an extraction site 50 km away. This meant that it took over an hour just getting it to the site. It was important that the clay shouldn’t get wet, so the site logistics had to be painstakingly organised. Even the morning dew had an influence on the processability of the material. And, if the material gets too dry, reworking is on the cards. So it was essential that none of the trucks got caught in the rain. Clay absorbs an enormous amount of water and, if it gets too wet, can hardly be worked with at all. Driving trucks down the steep sides of the site was also only possible when the ground was dry.
In turn, this meant that everything had to be perfectly coordinated when the weather was good to make best use of the favourable time window and get the daily quota of 1,200 t of clay-sand mixture in place. Above all, apart from the need for smooth and seamless site logistics, this also applied to the availability of the Wirtgen Group and John Deere construction equipment deployed on the project. ‘We’ve had nothing but positive experience with their machines for many years. On challenging jobs like this, it’s also a great advantage that we get the machines and the service from the same people. We got in touch with our branch of the Wirtgen Group in Windhagen to give them fair warning that we were starting the landfill job – just in case we might have needed their help in a hurry. But we couldn’t be happier, no problems at all, and the machines have been as good as gold’, said Michael Huthwelker, master of crafts in road construction at Wachenfeld.
The working schedule on the site was as follows: The material for each of the layers, both the limestone gravel and the clay-sand mixture for the next four layers, was unloaded on-site and spread with a bulldozer and a John Deere 622GP motor grader. The construction machines were assisted by a Topcon 3D-system with a total station to ensure precise compliance with the specified layer thicknesses.