What do a specialist foundation engineer and a secret agent have in common?
More than one might think. Equipped with many technical gadgets, both primarily work in the dark and you rarely see them doing their work. What the grenade launcher is for James Bond is the power drill for the specialist foundation engineer. Instead of a Walter PPK he fights with the drilling equipment for justice on construction sites. What makes his job more difficult is not nemesis Ernst Stavro Blofeld, but the fact that he does a lot of the work in the dark.
For example, when performing jet grouting to solidify the subsurface. These are injected into the ground almost blindly. Just as 007 only achieves mediocre results on the shooting range with closed eyes, the drill master is also reluctant to work with one sense less. For this reason, today’s expert sheds light on the dark. We present: Fuchs. Stefan Fuchs.
The site manager of PORR Bau GmbH has many years of experience in jet grouting. “The necessary construction parameter for jet grouting are based on long-term experience of the executing team. In order to evaluate these construction parameters, tests were made on the construction site in the past and sometimes still today, and these were subsequently exposed.” This was not only associated with considerable additional effort, but also with costs, since the tests could usually not be used for the actual measure. An improvement was needed. The TempJet idea was born.
License to measure
The TempJet system can be used to determine the diameter and cement content of the jet grouting. It enables measurements to be carried out in great depth directly on each jet grouting arranged by the project planner. The measurement is carried out by a probe, which can be installed over the drill pipe without special equipment or the use of additional equipment. The measuring chain was designed so that the diameter and the cement content along the column can be determined every 30 centimetres – regardless of the soil conditions and groundwater situation”, Fuchs explains. In addition, the process identifies inequalities in soil conditions, such as inclusions in the column produced or rinsing through groundwater flows – which is extremely important for quality.
The measuring chain itself only measures the maturing heat in the centre of the jet grouting. Using a cement sample in combination with the maturing heat, an algorithm can then deduce the diameter and cement content, because: the higher the maturing heat, the higher the cement content. The higher the diameter of the jet grouting, the longer it takes to cool down. The thermal conductivity and heat storage capacity of the surrounding soil have a significant impact on the result. Decades of research flowed into our calculation system to physically describe the soil”, Fuchs explains.
“Besides monetary savings of more than 70% compared to standard methods, the main advantage is clearly the measuring accuracy of +/- 10% and the possibility of evaluation in great depths”, says Fuchs. The evaluation of the measuring results takes usually between one and half to two and a half days, he explains. “In most cases however, the probes can be set before the well-deserved weekend so that the results are already at the table right on time for the start of the week.”
From Vienna with Love
The process has been on the engineering market since 2008 and has already been used on several hundred local construction sites and abroad. “TempJet measurements have been primarily been used in Austria, Germany, and France on our own construction sites, as well as by our licensing partners. However, also requests and projects from outside the EU reach us, for example from a project at the Ivory Coast.” For 2020, another 100 measurements are planned.
A small disadvantage of the system: it is single use only. In order to save resources and reduce costs, work is already underway to optimise the measuring arrangement so that multi use is possible by reusable probes.
As Q stands by 007, we at eguana support special engineers in your work with all kinds of technical gadgets. Where James Bond has a secret weapon with his OMEGA Seamaster, we also ensure that our construction heroes have more than just an ace up their sleeve. With our digital secret weapons, we do not defeat super villains, but we collect all measurement data of a construction site on a platform, where they can be graphically displayed, evaluated and analysed.
And unlike the premiere of the latest James Bond film, we don’t have to postpone anything (even in times of crisis).
About James Bond Stefan Fuchs:
To keep it short: There is nothing he can´t do.
After attending a secondary school, he continued with high school focusing on building constructions. Afterwards he graduated with a master´s degree in civil engineering and water management as well as training as a constructor. In his free time the hobby cook does not really enjoy a Vodka Martini (neither stirred or shaken), but rather a nice glass of wine while firing up the flame thrower grill for friends and family. If there is any time left next to all the secret work, he tries to get into programming to decode the foreign language of the eguanas.