AtlantJET anchors

ATLANT techology modifigation is combination with jet-grouting at 20 MPa pressure. To execute jet-grouting drill bits are equipped with nozzles and couplings are require with aluminium seals.

The main advantage of AtlantJet technology is significant increase pile diameter in comparison with Atlant piles/anchors at low pressure.

Comparison of techniques shows that application of jet-grouting significantly increases pile diameter. Pile diameter of standard Atalnt is 150-200 mm and pile diameter at application of high pressure is about 400-700mm.

Application of jet-grouting in some cases is reasonable. These cases are pile installation in soft soil when you need to increase diameter to ensure bearing capacity. In other tasks increase of pile diameter is required for piles intercrossing, for example for installation of plugs between pits and close buildings etc.

Type Rod diam., mm Wall thickness, mm Yield point, MPa Breaking point, MPa Bearing capacity, kN Ultimate load, kN
30×8 30 8 470 590 260 326
42×8 42 8 550 690 470 590
42×10 42 10 550 690 553 694
57×6 57 6 600 790 576 759
57×8 57 8 590 790 727 973
57×10 57 10 580 790 856 1166
73×9 73 9 580 790 1050 1430
73×11 73 11 600 790 1285 1692
95×13 95 13 580 790 1942 2646

Installation technology

1.1. Well drilling

  • Grout pressure 200 MPa;
  • Flushing grout Water:Cement ratio – 1.0.

No temporary casing needs!

1.2. For grout preparation should be applied proper quality cement and water. Water should not contain impurities which may cause the metal corrosion and prevent the cement solidification.

1.3. Drilling should be performed only upon condition that grout returning and pulp lifting. If grout returninig stops it is necessary to reduce rod feeding speed or suspend feeding without rotation stopping. It is possible to continue drilling only after resumption of the grout returning.

2. It should be noted that grout pressure varying makes possible to increase the anchor root diameter, which increases its bearing capacity.

No tension need!

AtlantJET anchors

Equipment, required for installation of AtlantJet anchor piles include a drill rig, high pressure pump and mixing plant.

FIGARO drill rigs

Compact drill rigs sgaro are designed with separate hydraulic unit and developed for soil anchors and piles installation.

Rotary heads with high torque ensure high productivity of the rigs. Rigs Figaro Maschine can be mount on crawlers. Hydraulic stations depending on operating conditions are supplied with diesel, electric or pneumatic drive.

The 3-wheeled drill rig Figaro Pauk was designed for use on steep slopes and embankments. This allows drilling to be carried out with low machine weights and in difficult and dangerous on-site conditions.

Drill Figaro Lafette FL400

Drill Lafette is used for underground construction works:

  • Installation of augercast piles;
  • Reinforcement of buildings foundations;
  • Jet-grouting;
  • Installation of anchors.

Figaro Lafette FL400 is intended to work with hydraulic excavator of over 18-t weight.

High pressure pump

To execute jet-grouting technology is required using high pressure pumps with following technical data:

  • Pressure 200-500 bar;
  • Capacity 200-400 l/min.

The most popular high pressure pumps are Tecniwell TW 351/352.

VORTEX mixing plants

Vortex high-capacity mixing plants allow preparing cement grouts containing up to 6 components, according to given weight ratio.

Vortex plants are fully automatic and don’t need constant presence of the operator. The operator simply defines a mixing plant working programme for the whole shift.

Generalized Kranz's force equilibrium method for stability analysis of an anchored wall

The polygon of forces acting on the soil wedge at limit equilibrium involves the active earth pressure of the retained soil Pa, the shearing resistance of the soil (i.e., Sс and , and the wall reaction Pa. The polygon of forces acting on the structural wall element involves the soil pressure PA. The resisting prestress anchor load required to maintain equilibrium, the passive resistance of the foundation soil Pp, and the basal soil reaction Fb. The decision power of the polygon allows you to define the horizontal projection Pa bearing capacity of the anchor, which leads hatched the prism in a state of marginal stability.

Kranz equation is used to define the factor of safety

FS = RL/Rm  with  RL =Fand Rm = T.

Bearing capacity calculation

Anchors and piles bearing capacity according DIN 1054-2005:

Fd = π D lqsk  with  D = dw kd

dw – well diameter,

kd – anchor diameter enhancement factor,

lk – anchor root length,

qsk – anchor skin friction.

Recommended values of anchor diameter enhancement factor shown in Table:

Soil type

Enhancement factor kd

Gravel

2,0

Sand

1,5

Sandy clay, clay loam

1,4

Clay

1,3

Rock

1,0

In the Table below you can see calculated skin friction values

Soil type

Skin friction, qsk, kPa

Medium and coarse gravel

200

Sand, semigravel

150

Sandy clay, clay loam, clay

100