Injection Piles and Anchors

Bored injection piles or as they are called often, root-shaped piles gained the distribution in Italy in sixties years of the 20th century. They are named to the shaft form which they form in soil, and also the form of the pile columns having the numerous local broadenings received when forcing solution in a slit under pressure. Injection piles represent rather thin piles with a diameter of 15-25 cm arranged at different slope angles and with big relative burying which characterizes the pile length relation to its diameter. Trunk material – the reinforced compact-grained concrete or cement mortar. A manufacture method – a concrete injection in a slit under pressure.
Injection piles have the greatest distribution in case of gain of the bases and bases of the reconstructed and restored buildings and constructions, for anchor fixing of retaining walls, instead of spreader system, compensating the rolling-over moment operating from soil on construction. When using anchor fixing of retaining walls, in a ditch it is possible to work without restrictions.
When using classical technology, in the slit drilled to a project mark under protection of an upsetting pipe or clay solution the injection tubes connected to accessories or anchor pull are set and plugging solution with In/C – 0,4 is forced. 0,5 to its output on a surface and a repeated injection of solution in 10 – 12 hours. As a result of an injection the reliable communication of an anchor with soil is provided.
When using technology of the hollow screw placement of accessories or anchor pull is executed after filling of a slit with solution, if necessary through a certain period the repeated injection is executed.
Now in world practice there is a tendency to combine specified technological operations (drilling, reinforcement, injection) in one with support of the necessary quality level and reliability is viewed. Therefore Delta Drilling Company uses the boring high-strength tubular rods “Titanium” (a figure 1) Ischebeck and self-produced tubular anchor rods pull of original construction which remain in a slit as a reinforcing element and pull of an anchor. The trial conctrection of such anchor piles with a diameter of 150 mm executed for the first time in Belarus by our company, and their tests by P18-04 technique to SNB 5.01.01 made on object of multifunction hotel complex in 2010 showed high bearing capacity of anchors and high performance.
Injection anchor piles with a diameter up to 200 mm to be applied in the same projects where traditional injection piles and an anchor are put and thanks to a fast and effective method of installation in one step represent reliable alternative of successful use of gain of the bases, fixing of rabbeted walls of ditches, reinforcements of slopes and exponentiation of the bases of the constructions subject to overthrow.

placement of accessories or anchor pull is executed after filling of a slit with solution, if necessary through a certain period the repeated injection is executed.

According to figure 2, technological sequence of operations is as follows:
1. Drilling of a slit on project depth is executed by the tubular rod pull with a boring head with use of cement mortar with In/C – 1,0. 1,2 as flushing liquid. This solution carries out particles of the destroyed soil and provides primary injection and impregnation of soil, filling cavities and cracks.
2. On reaching a project mark more dense cement mortar with In/C – 0,4 moves. 0,5 under the pressure up to 25 atm. This solution in case of movement forces out primary solution from below-up, at the expense of a viscous consistence and friction about the rod and soil executes a packer role, thereby molding soil and creating a root of an anchor and a jacket from a pure cement stone of high strength round tubular pull.
3. After a solution durability set by means of sleeve joint the pin joins the rod and the tension of an anchor and its fixing to a banding belt is made.

Figure 2. Sequence of operations

Construction of such anchor piles requires the minimum set of a drilling equipment – any can be used even the small-size drilling rig with the swivel, the mud pump and the adder of cement mortar. All types of rods are set by the same method, irrespective of their size and load of a pile, only the drilling equipment shall approach on the appropriate standard size. For the conctruction of anchors when fixing retaining walls our company applies installation to jet cementation of PSM-20 soil of Soilmec (a figure 3) with station of agitation downloading of solution (a figure 4). Use of this installation in subsequent in case of equipment of a boring head nozzles and in case of forcing pressure increment to 300 atm. will allow to receive anchor piles of the increased diameter and the increased bearing capacity.

• high performance, is 2 – 3 times higher in comparison with traditional systems;
• lowering of expenses of manual skills due to combining of AND operations of absence of need for application of an upsetting pipe or bentonite solution in unstable soil;
• high bearing capacity – the cement mortar given under pressure washes out and completely fills a borehole, molding its walls, increasing thus connection with soil;
• reliability and longevity, a cement body provides simple continuous protection against corrosion.