New method for retaining walls

It is reassuring that whenever the building industry is faced with a challenge, some individual or company will inevitably produce a simple, sensible solution.



The side protection of building excavations is still a challenge, technically as well as eonomically. Temporary sheet piles or soldier pile shorings have the disadvantage that valuable space is wasted and their use is often completely forbidden because of the damage vibration may cause to neighbouring structures during driving and extracting. On the other hand, diaphragm walls avoid these problems but are very expensive.

Secant pile walls made by a special version of the Mobilram Drill Rig from Imeco/Austria are often the ideal solution. The Mobilram Drill Rig consists of a hydraulic base machine of sufficient weight and power, a telescopic leader mast and a double rotary head which drills the casing and the hollow stern auger simultaneously in the ground using opposite rotation directions. After reaching the final drilling depth, concrete is poured through the swivel and the casing and auger can be retracted. Reinforced steel cages or I-beams are used to meet the static requirements of the secant pile wall.
The secant pile wall can be designed as an integrated part of the final concrete structure Reinfored steel cages or I-beams are used to meet the static requirements of the secant pile wall

The Mobilram Drill Rig makes it possible to install secant in situ concrete piles of 400-600 mm diameter noiselessly and vibration free, and the double rotary head, together with the automatic leader alignment system guarantees precise vertical piles, which have not been achieved before. Depending on the final excavation level, one or more rows of ground anchors are used to stabilise the structure. The secant pile wall not only works as permanent shoring but can be designed as an integrated part of the final concrete structure offering considerable savings for the foundation of the building.

The drilling tools can be equipped with rock cutters to penetrate hard soil or even existing old brick walls and concrete foundations. The average production rate of 150-250 m of secant concrete piles per day makes it one of the most economical solutions for retaining walls.

But the Mobilram Drill Rig offers still more advantages. The telescopic leader folds down easily, giving the rig maximum manoeuvrability even on small sites. The leader may also be equipped with a standard rotary head to work with continous flight augers or soil displacement augers. With a hydraulic vibrator or impact hammer, a wide range of pile driving works (sheet piles, H-piles, steel casings, etc.) can be done with unmatched performance.
Difficult jobs require sophisticated machinery



Noiseless and vibration free techniques can now be used for the side protection of building excavations