Double Sliderail Elements

General:

The TWF slide rail elements are a mechanised trench shoring system for nearly all sites and ground conditions and offer maximum performance and safety up to 7.6 m trench depth. All parts of the elements are manipulated, installed and extracted by a hydraulic backhoe excavator of 25-40 tons operating weight. Element plates are available in various lengths (2000-7000 mm) and heights of 2400 and 1400 mm. Slide rails can either be single slide rails with only one guide for the plates for trench depths up to 4000 mm or double slide rails with two guides in standard or heavy duty XL version for depths of 4800, 6200 or 7600 mm. Only one heavy duty 'rolling' strut accepts the soil pressure which can be placed at different heights and allows a clear head room of up to 2500 mm.



Main parts:

One slide rail element consists of following main parts:

  • Element plates (length 2000-7000 mm, height 2400 and 1400 mm)
  • Single or double slide rails (length 3000-6500 mm)
  • Rolling struts for single, double and heavy duty slide rails XL
  • Strut extensions from 150-3000 mm for maximum trench widths up t 8 m


Advantages:

The TWF slide rail elements offer following main advantages:

  • Usable in all soil conditions (with proper dewatering system)
  • Excellent performance (in average 4-6 sections per day = 14-24 m per day)
  • Large head room below rolling strut for large diameter pipes or culverts
  • Only one excavator and two men for manipulation, installation and extraction
  • No crane, power pack or vibrator is required
  • Competitive cost per m2 and use compared to other shoring systems
  • Long durability and little efforts for repairs and maintenance
  • Designed according to DIN and approved by the German TBG


Part Details:

The element plates are made as sandwich panels of 100, 120, 130 and 150 mm thickness (depending of length and safe working load) with a reinforced top section and a cutting edge at the bottom.
Single slide rails with one guide for the plates are available in lengths of 300, 3500, 4000 and 4500 mm depending on the required trench depth.
We offer two versions of double slide rails:
Standard double slide rails in lengths of 4500-6500 mm in 500 mm increments.
Heavy duty double slide rails XL in lengths of 6500, 7500 and 8500 mm.
The different slide rails come also with different rolling struts to accommodate various slide rail dimensions and working loads. Minimum working width is 1240 mm for the single and the standard double slide rails and 1830 mm for the XL slide rail system.
The strut extensions are mounted between the rolling struts and fixed by 12 bolts at each side. 12 different extension lengths allow to make trench width in 150 mm increments.



Installation:

Two slide rails and two rolling struts (with extensions) are mounted together in the required trench width forming a slide rail 'frame'.
The excavator starts with a preliminary excavation of app. 2-3 m depth (but only until the soil begins to slide) and in the length of one shoring element. Then the excavator lifts one slide rail frame into the trench and puts two shoring plates at the left and right side into the outer guides of the rails. Finally the element is closed with a second slide rail frame, so that the plates are fully guided at both ends.
The excavator continues excavating within the element pushing down the shoring plates using the lower-and-cut method: the backhoe excavates horizontally as close as possible along the shoring plates at both sides of the trench and pushes down the plates with the full bucket. Also the slide rails are sunken down in the same way. When the outer plates are at street level, the excavator installs the second pair of plates into the inner guides of the slide rails and proceeds the excavation and sinking-down procedure until reaching the final excavation level.
Plate protectors are provided to avoid any damage of the plate top by the excavator during the push-down procedure and 4-leg lifting cables assist the installation and extraction of the shoring system.



Extraction:

After pipe laying the trench is filled back in the specified layers and the plates extracted accordingly, so that the backfilling material can be compacted directly against the nature soil, avoiding ground settings to a minimum.



Safety:

Please observe the following carefully (this is not a complete listing):

  • All our trench boxes are approved by the German TBG for a certain working load (i.e. 44.70 kN/m2 for the S600, length 3500 mm) which is shown in our leaflets and technical data sheets. Always check the actual soil pressure and make sure that it is within the limits of the approved working load.
  • Special care has to be taken with the groundwater. All recommendations for a certain installation depth are made under the precondition that the groundwater is removed before installing any trench shoring equipment. Beside for safety reasons the groundwater in the trench creates great problems for the excavation (bucket full of water, limited visibility, etc) and reduces the possible working performance significantly.
  • Take special precautions that nothing can fall into the trench. The safest way is to let the shoring system stand 150 mm above the ground.
  • Never use bended spindles as their buckling loads reduced.
  • All pins have to be secured by proper safety clips.
  • Top boxes have to be connected to the base by plate connectors.
  • No worker should stand in the trench while the shoring is sunken down as the excavator operator has limited sight to the working area.
  • Workers have to wear hard hats, gloves and safety shoes and observe all standard safety regulations carefully.