Cutter and grab

Bauer trench cutters and Bauer hydraulic grabs are equipment for the panel excavation for the execution of cut-off walls. The centerpiece of the Bauer trench cutter system consists of a steel frame with two gearboxes attached at its base, which rotate in opposite direction around their horizontal axis. Cutter wheels suitable for the prevailing ground conditions are mounted on the gearboxes. Selecting the most suitable type of cutter wheels (equipped with flat teeth, round shank chisels or roller bits) is essential for cutter progress which mainly depends on the geological conditions (particle size, density, abrasiveness, compressive strength, etc.). The accurate determination on the trench cutter for your project depends on the project ground conditions, the required trench width and wall depth. The ideal base carriers for Bauer trench cutter and mechanical or hydraulic grab equipment are BAUER MC 76, MC 86, MC 96 and MC 128 duty-cycle cranes. The entire hydraulic power supply of the attached cutter/hydraulic grab is provided by the hydraulic systems of the MC duty-cycle cranes which have been specially designed for those applications. Cutter and grab are available for a nominal width of 640 mm, 800 mm, 1.000 mm, 1.200 mm, 1.800 mm and 2.200 mm, and panel length of 2800 mm and 3.200 mm, however also special measures for width can be manufactured, if required.

Rotary drilling rig

Bauer rotary drilling rigs are used to construct a single pile or (secant) pile wall or – in combination with diaphragm wall elements – a hybrid wall. The BG hydraulic drilling rigs like BG 30 or BG 45 are ideally suited for drilling cased or slurry-supported boreholes, with the Kelly-system and special drilling tools demanded by the individual geology on the project. The segmental steel casings for cased boreholes are installed by rotary drive or optionally by hydraulic oscillator powered by the drilling rig or additional powerpack. Drilling tools are available for diameters from 600 mm to 3500 mm.

Small diameter drilling rig

The main equipment for the drilling and grouting method are the Bauer hydraulic drilling rigs of the KLEMM KR 800-series. These modern and extremely compact rigs are particularly suitable for the different drilling applications.

The drilling rigs will be fitted with hydraulic drifters from the Eurodrill HD-series, with different types of drill rods and drill tools to suit the geology and depth required for the individual project. After extensive checks over borehole deviation the grouting process will be executed. The accurate determination on grouting equipment (pump type, mixer, packer type, etc.) depends inter alia on soil conditions and the required grouting material.

Mixed-in-Place

Bauer Mixed-in-Place (MIP) equipment is developed specifically for use in the overburden (granular, slightly cohesive soils). The entire hydraulic power for the rotary drives of the attached triple augers is provided by the hydraulic system of the base carrier, which has been specially modified for those applications. Base carriers like BAUER RG 19T, RG 25/27S or modified BG are chosen according to the final depth and the required nominal width to be achieved. Triple augers are available for a nominal width of 370 mm, 550 mm and 750 mm.

Cutter-Soil-Mixing

Cutter-Soil-Mixing (CSM) equipment derived from Bauer trench cutter technique. Depending on the required depth of the cut-off wall, the cutter-mixing unit is held and guided by round Kelly bar or by a Mono Kelly with rectangular cross-section. Cutter wheels break up the soil matrix and mix it with cement slurry to a homogeneous soil-cement mortar. The system is applicable in various soil conditions – even in hard or layered strata. Cutting and mixing head are available for a nominal width of 600 – 1,200 mm.

Jet grouting

Attaching the required jet grouting equipment, the universal Bauer BG base carrier and KLEMM hydraulic drilling rigs can be converted for the jet grouting works. Additional equipment, like jet grouting drill rods, high pressure jetting pump and a mixing plant are necessary.

Soil improvement

The ideal base carriers for Bauer soil improvement are duty-cycle cranes, like BAUER MC 96 and MC 128, and BG 28 and BG 40 for Deep-Soil Mixing (DSM). The entire hydraulic power supply of the attached soil improvement equipment is provided by the hydraulic systems of the MC duty-cycle cranes, and BG drilling rigs. Depending on the required technique (stone columns, vibro compaction, dynamic compaction, DSM) the additional equipment (vibro probe, pounder/weight, drilling / mixing tool) will be connected with the base carrier.

The max. DSM depth that can be executed with a single stroke can be up to 31m, the diameter of the mixing tool can be designed individually (ø 600 – ø 2000mm).

Mixing and desanding unit

The open trenches of diaphragm wall elements and possibly piles are supported by slurry. During the preparation of bentonite slurry, the bentonite powder has to be mixed intensively with water. This is achieved by pump mixers or colloidal mixers. Single-phase slurry mixes for cut-off slurry walls consisting of multiple components, such as rock powder, cement, bentonite and water, are produced by Bauer MAT mixers as well. Bauer MAT desanding plants are developed specifically for the use with trench cutters to separate the cuttings from the slurry used to support the open trench and to transport the cuttings.

The plants are characterized by the following features: Modular construction throughout the entire plant unit and, therefore, the ability to match treatment capacity to soil type and cutter output capacity. Advantages: secondary circulation with desilter or centrifuge possible, short set-up and dismantling times and containerized transport dimensions.