EP1710355A1 - Mixed-in-place Diaphragm wall with filigree beams - Google Patents

Abstract

The device, after manufacturing a wall (6), has several elements (14) inserted into the wall having a larger surface extending transversely to a wall level. The elements are perpendicular running longitudinal bars which are connected with lobes or arranged at diagonal staves (2, 2', 2'') by welding (4) with one another. The elements are fixed to each other by constructional binding staves or tie plates (3, 3', 5) and the longitudinal bars and the diagonal staves (2) extend over a part of the wall depth.

Description

The invention describes a device for the concentrated introduction of force into unreinforced shoring walls or diaphragm walls in the ground, which are produced by the mixed-in-place method or as single-phase sealing walls with self-hardening support suspension.

The mixed-in-place method describes a manufacturing technique in which the pending soil is converted into a soil mortar by one or more rod-shaped agitators or slit-wall mill-like devices in the soil. In this case, water and binder and possibly also additives or bentonite is added via the stirring tools or milling and mixed the soil into a mortar.

Typically, such walls are used in the mixed-in-place process to create waterproofing screens in the ground to retain the groundwater.

The compressive strength of these mixed-in-place walls is in the range of 1-2 N / mm ² for pure sealing measures.

In particular, in non-cohesive soils can be achieved by addition of suitable binders, preferably cement-based, but also compressive strengths, which are between 5 and 15 N / mm ² , and thus such walls can accommodate even larger loads.

These so-called static, effective walls are suitable to be used for temporary Baugruensicherungsmaßnahmen. That is, such walls can be unilaterally exposed and serve as a Verbauwand.

The advantages of these statically effective mixed-in-place walls are that, firstly, there is no excavated material that has to be moved away, and second, the material of the wall is significantly cheaper than concrete diaphragm walls.

Further advantages are that with contaminated soils the soil does not have to be excavated and disposed of expensively, but this is immobilized by the addition of cement and can remain in place.

If such pits with static-acting mixed-in-place walls are unilaterally exposed, they must be anchored back to absorb horizontal earth pressure forces or forces from the water pressure.

This back anchoring can be done in such a way that in these slot wall-like walls after the mixed-in-place process at intervals, pairs of rolled steel profiles are used, which are back-anchored with conventional injection anchors.

These steel profiles usually consist of IPB beams or welded structures with double U-beams.

The mixed-in-place wall between these vertical girders can remain unreinforced because, due to the wall thickness of about 40-80 cm between the individual girders, horizontal pressure vaults can form within the wall body which compresses the earth pressure forces in the fields Transfer carrier structures.

Since mixed-in-place retaining walls are generally only used for a short time, because the designs made of rolled steel profiles are expensive due to their longevity, the price of such temporary mixed-in-place retaining walls is unnecessarily increased.

The same situation applies to diaphragm walls, which are produced in the single-phase process with a self-curing support suspension of water, cement and bentonite.

Recovery of these steel structures after use of the temporary shoring wall is not possible due to the high adhesive stresses in the mixed-in-place walls.

The invention has the object to find a low-cost device, which still makes a concentrated application of force for anchoring back such unreinforced walls possible.

The object is achieved according to the features of the claims by the installation of a special device in the field of concentrated application of force.

• Figur 1 zeigt beispielhaft einen horizontalen Schnitt durch eine vertikale Mixed-in-Place-Wand 6, in der erfindungsgemäße Vorrichtungen zur konzentrierten Krafteinleitung eingebaut sind.
  Die Rückverankerung erfolgt über Zugstangen 9, die über eine nachträglich an der Wandoberfläche befestigte Kopfplatte 8 und ein Verankerungselement 7 die Kräfte übertragen.
• Figur 2 zeigt die Ansicht eines erfindungsgemäßen Elementes 14, welches aus Längsstäben 1,1' und damit verschweißten Diagonalstäben 2 besteht.
• Figur 3 zeigt einen horizontalen Schnitt durch eine Mixed-in-Place-Wand 6, bei der die Krafteinleitung durch eine in der Wand versenkte Kopfplatte 12 erfolgt sowie geeignete Mittel, um die Verankerungskraft auf Elemente 14 zu übertragen.
• Figur 4 zeigt einen horizontalen Schnitt durch eine Mixed-in-Place-Wand 6, bei der im Abstand 16 erfindungsgemäße Vorrichtungen 14 zur konzentrierten Krafteinleitung angeordnet sind.
• Figur 5 zeigt Ausführungsvarianten mit dreiecksförmiger Anordnung der Elemente 14 sowie deren Abwandlungen.
• Figur 6 zeigt eine Ausführungsvariante, bei der die Vorrichtung mit einzelnen Diagonalstäben 2' oder mit dreieckig gebogenen Diagonalstäben 2" verbunden ist.
• Figur 7 zeigt eine Ausführungsvariante, bei der die Diagonalstäbe 2, 2', 2" zwischen den Längsstäben 1, 1', 1" eingeschweißt sind.

The device according to the invention is explained in more detail in FIGS. 1-7.

• Figure 1 shows an example of a horizontal section through a vertical mixed-in-place wall 6, are installed in the inventive devices for concentrated application of force.
  The anchoring is done via tie rods 9, which transmit the forces via a later attached to the wall surface head plate 8 and an anchoring element 7.
• Figure 2 shows the view of an element 14 according to the invention, which consists of longitudinal bars 1,1 'and diagonal bars 2 welded thereto.
• FIG. 3 shows a horizontal section through a mixed-in-place wall 6, in which the introduction of force takes place by means of a head plate 12 sunk in the wall and suitable means for transferring the anchoring force to elements 14.
• FIG. 4 shows a horizontal section through a mixed-in-place wall 6, in which devices 14 according to the invention for the concentrated introduction of force are arranged at a distance.
• FIG. 5 shows variant embodiments with a triangular arrangement of the elements 14 and their modifications.
• FIG. 6 shows a variant in which the device is connected to individual diagonal bars 2 'or to triangularly bent diagonal bars 2 ".
• FIG. 7 shows a variant in which the diagonal bars 2, 2 ', 2 "are welded between the longitudinal bars 1, 1', 1".

A special feature of the invention lies in the design of the elements 14 and their arrangement in the unreinforced mixed-in-place slot or in an unreinforced single-phase sealing wall.

The elements 14 consist of substantially mutually parallel longitudinal bars 1, 1 ', 1 "..., which are non-positively connected by zig-zag or wavy arranged diagonal bars 2.

For the diagonal bars 2, a steel bar can be formed zigzag or wavy over a longer range (Figure 2) or single diagonal bars 2 'or individual substantially triangular curved bars 2 "are used (Figures 6 and 7).

Static requirements may require that the longitudinal bars be connected to each other on two sides or through several layers of diagonal bars (Figure 1).

This connection is made by statically effective and measured welds. 4

These welds 4 are preferably arranged in the arcs or tips of the diagonal bars 2 and the dimensions of the diagonal bars 2 are chosen so that the longitudinal bars 1, 1 '... are as far outside in the wall and thus larger bending moments can be accommodated.

The inclination angles β, β ', with which the diagonal bars 2 run towards the longitudinal bars, are preferably in the range between 30 ° and 60 °.

For reasons of force flow, the diagonal bars 2 between the longitudinal bars 1, 1 'should be as straight as possible.

FIG. 5 shows a variant embodiment in which elements 14 are arranged triangular in relation to one another on the left side.
On the right side, two elements 14 are combined to form a triangular element 19, in which a longitudinal bar 20 and longitudinal bars 1 'are non-positively and statically operatively welded to one another via two or more diagonal bars by welds 4, 4'. It may be expedient that in this case the size of the cross-sectional area of the longitudinal bar 20 is different than the cross-sectional area of the longitudinal bars 1 '.

The longitudinal bars 1, 1 '... and the diagonal bars 2 are preferably made of profiled or ribbed structural steels with circular cross sections. In principle, however, all cross-sectional shapes are conceivable.

The embodiment of the elements 14 can be made both of smooth steels, but preferably of steels, which have a certain roughness by mechanical processing or coating, which causes higher adhesive stresses in the floor mortar.

To increase the service life of the shoring wall, it may be useful to provide the elements 14 with anti-corrosion coatings.

Preferably, only one earth-side bar 1 and one air-side bar 1 'are arranged on each element 14, whose cross-sectional areas can also vary.

For particularly high re-anchoring forces, it may be expedient to equip the elements 14 with a plurality of longitudinal bars 1, 1 ', 1 "for static reasons.

The longitudinal bars 1, 1 'can lie on the same side of the zig-zag or wave-shaped arranged diagonal bars 2 or on different sides. This variant is shown on the right side of FIG.

Likewise, the diagonal bars can also be welded between the longitudinal bars (FIG. 7).

The elements 14 are preferably installed vertically and aligned so that their larger expanse area comes to lie across the plane of the mixed-in-place wall.

The angles α and α 'of these surfaces to the wall normal are preferably in a range between -45 ° and + 45 °.

For optimum flow of force, at least two or more elements 14 are combined with one another at the locations of the concentrated introduction of force.

Since the elements 14 are introduced into the freshly prepared mortar only after production of the mixed-in-place wall, which is done by pure impressions or easy vibrating, the elements 14 must be fixed by suitable binding plates 3, 3 ', 5 in their arrangement to each other.

The elements 14 are connected by constructive welds or by binding wire with the binding plates.

The binding plates can also be replaced by rods.

Preferably, the binding plates 3, 3 ', 5 are arranged at intervals of about 0.5 to 2 m.

The concentrated application of force across the wall surface serves to absorb the horizontally acting earth pressure forces or the water pressure and takes place via injection anchors or bar injection piles.

In Fig. 1 transmits the pull rod 9, which may consist of strands or steel bars, the forces from the earth pressure on a load-distributing head plate 8 on the wall surface 10 and this top plate is set only after exposure of the wall and straightening. Anchoring means 7 are wedges or nuts. In this application, the anchor heads protrude over the wall surface.

In Figure 3, an embodiment of the invention is shown, in which the force is not introduced by a support plate, which rests against the wall surface, but the support plate 12 is sunk. The support plate 12 transmits the forces by welded web plates 13 on short pieces of angle iron 11 'or U-profiles eleventh
Through these forces enter the elements 14 directly or indirectly.

Preferably, the angle iron or U-profiles are welded to the elements 14 for this purpose.

The dimensions of the elements 14 are chosen so that they have sufficient steel coverage through the floor mortar within the floor mortar wall 6. It lies in the centimeter range.

The correct location of the combination of multiple elements 14 in the mixed-in-place wall can be achieved by additional spacers, which are not shown separately in the drawings.

FIG. 4 shows the static mode of operation of the back anchoring of an unreinforced wall produced according to the mixed-in-place method.

For this purpose, combinations of a plurality of elements 14 at a distance 16, which according to experience is in a range between 1 and 3 m, are arranged in the mixed-in-place wall 6.

In the area of these elements 14, the anchoring takes place via conventional injection anchors and their tie rods. 9

In the field area 15 between the force introduction points vaults 17 are formed, by which the earth pressure is removed from the field area to the force introduction areas with the elements 14.

The device according to the invention makes it possible to use the mixed-in-place process economically also for back-anchored construction pit walls with the use of inexpensive installation elements.

Claims (9)

Apparatus for the concentrated introduction of force into unreinforced diaphragm walls in the soil, which are produced by the mixed-in-place method, wherein the pending soil is mixed in situ, for example by means of rod-shaped stirring tools or by milling with the addition of binders to a floor mortar or in slot walls produced with self-curing support suspensions (single-phase sealing walls)
and in which the forces to be introduced are directed transversely to the wall plane, characterized
in that, after the wall (6) has been produced, a plurality of elements (14) are introduced into the wall in such a way that they extend with their larger area transversely to the wall plane
and that these elements (14) consist of substantially vertically extending longitudinal bars (1,1 ', 1 "...) which are provided with serrated or undulating diagonal bars (2, 2', 2") by statically effective welds (4). are positively connected with each other
and that a plurality of elements (14) by means of constructive binding rods or binding plates (3,3 ', 5) are fixed in their arrangement to each other
and that the longitudinal bars (1,1 ', ...) and the diagonal bars (2) extend over at least a part of the wall depth. Device according to claim 1, characterized
that the elements (14) at angles (α, α ') are inclined to the wall surface normals, which is preferably be in a range of + 45 ° to -45 °. Device according to one of claims 1 to 2, characterized
that the longitudinal rods (1, 1 ', 1 ", 1"', ...) are welded on the same side or on different sides of the serrated or wave-shaped arrangement of diagonal bars (2). Device according to one of claims 1 to 3, characterized
that the longitudinal bars (1, 1 ', 1 "...) or the diagonal bars (2) consist of smooth or ribbed or profiled steel bars. Device according to claim 4, characterized
that the longitudinal bars (1,1 ', 1 ") and diagonal bars (2) have a corrosion protection coating. Device according to one of claims 1 to 5, characterized
that the diagonal bars (2) between the longitudinal bars (1,1 ', 1 ") are formed as straight as possible and at angles (β, β') in the preferred range between about 30 ° and 60 ° to the longitudinal bars (1, 1 ' ...) are inclined. Device according to one of claims 1 to 6, characterized
that the introduction of force in the region of the elements (14) by tie rods (9), anchoring elements (7) via top plates (8), which are arranged after exposing the wall surface on the wall surface. Device according to one of claims 1 to 7, characterized
that the introduction of force in the region of the elements (14) by tie rods (9) and anchoring elements (7) via recessed head plates (12) which are directly or indirectly connected via winkelike or U-shaped parts (11) with the elements (14) , Device according to one of claims 1 to 8, characterized
in that the concentrated introduction of force is effected by elements (19) which in horizontal section represent a substantially triangular arrangement of earth-side (21) longitudinal bars (20) and air-side (10) longitudinal bars (1 '), wherein the non-positive connection via at least two serrated or Wavy arranged diagonal bars (2, 2 ', 2 ") and statically acting welds (4, 4') takes place.

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