FR2648848A1 - Pneumatic joint between panels of cast walls - Google Patents

Abstract

Joint for cast walls with pneumatic wedging and removal from the formwork after setting of the concrete. The invention relates to an inflatable joint which serves to form the connection between panels of cast walls and which is removed from the formwork after the setting of the concrete. The joint consists of a metal frame on which two seats 2, consisting of metal tube segments, contain two inflatable cells 3. They are connected at their upper part to threaded tensioning elements and are over-tensioned by a slide during the tearing-off. They communicate with each other via a flexible coupling and are inflated with compressed air. They bear on the walls of the bore and act as a sealed closure piece. The joint is removed from the formwork after setting of the concrete by deflating the cells. This joint permits incorporation of a sealing profile of the "water stop" type. This joint is intended in particular for the construction of walls cast in the ground.

Description

 The present invention relates to a joint between panels of diaphragm molded walls and pneumatic formwork after setting of the concrete.

 The diaphragm walls are executed by juxtaposed, independent panels. Between each module, the connection is made using a circular metal tube functioning as a sliding formwork.

 The extraction of these joined tubes must be done while setting the concrete.

 This has always been the major problem in the realization of diaphragm walls.

- If the extraction is too fast, the concrete bypasses the tube and in.
will be excavation problems for the adjacent panel.

- If the extraction is done too late, the joint tube remains stuck and it
is necessary to resort to important technical means: ar
hydraulic racheurs, big crane to take them out.

- In all cases, the junction between the panels of diaphragm walls
is not perfect and this is where the water comes in
are to be feared.

 The method according to the invention makes it possible to improve the system and to extract the joints after the concrete has set.

 The accompanying drawings illustrate the invention.

 Figure 1 shows, in cross section, the seal according to the invention.

 Figure 2 shows a front view of the seal, Figure 3 a side view of the seal.

 The joint consists of a metal frame (1) of length and width adapted to the diaphragm walls to be produced.

 On each side of the joint, and over its entire length, two housings (2) constituted by segments of metal tubes contain two inflatable flexible cells (3).

 These cells (3) are fixed to the lower end (5) of the metal frame (1).

 The flexible cells (3) are tightened at their base so that the sleeves (5) are completely inside the chassis.

 A metal spade extends the chassis in its lower part (4).

 The cells are connected in the upper part by closed metal sleeves (6) to two threaded tensioners (7).

 The cells are stretched over the frame.

 A slide system (8), integral with a handling yoke (9), allows the cells to be extended for lifting.

The slide rests on a metal profile in the form of
H (10) secured to the chassis.

 The slider passes through a light (11) arranged in this profile (10).

 The cells are connected together at the upper sleeves (6) by a compressed air hose (12).

 The cells are inflated with compressed air by connecting a hose to the end piece (13) which connects the hose (12) via a tee (14).

 Valves (15) isolate the cells from each other.

Pressure gauges (16), mounted on the circuit, make it possible to control the inflation pressure.

 On the front of the seal. two metal plates (17) are welded to the frame (1) to define the profile of the joint.

 A reservation (18) for incorporating a waterproof profile is provided in the axis of the joint.

 On the rear of the chassis, UPN type profiles (19) are welded to allow the skip to be guided during the excavation of the adjacent panel.

 For its descent into the excavation of diaphragm walls, the cells (3) are deflated. The joint is narrower than the trench and its descent is easy.

 The cells are crushed at the bottom of their housing by the hydrostatic pressure of the bentonite.

 The joint is planted at the bottom of the panel, the metal spade (4) allows the setting and sealing at the bottom of the panel.

 Once the seal is in position, the cells are inflated with compressed air (7 bars) and rest on the drilling walls.

 The lateral grip is considerable and prevents any movement of the joint.

 Concreting can be carried out.

 The pneumatic setting of the seal in the diaphragm wall acts as a sealed shutter.

 Concrete bypasses are removed.

 The concrete, along the joint, no longer undergoes the segregation effect due to the loss of laitance, and the quality of the concrete is uniform over the entire thickness of the wall.

 The joint is recovered after the concrete has set.

 The cells are independent of each other, the alternative inflation and deflation if necessary take off the joint from the concrete.

 The joint can then be removed by crane without difficulty.

 As the extraction of this joint is done after the setting of the concrete, it is possible to insert in the reservation a waterproof profile type "WATER STOP" or similar to improve the tightness between panels.

 The seal can remain in place while drilling the adjacent panel.

 The back of the joint is provided with metal profiles which serve as a guide for the descent of the bucket during the excavation of the next panel and allow better alignment of the panels with each other.

 By way of nonlimiting example, the joint will have dimensions covering the widths of walls from 0.40 to 1.00 m for depths which may exceed 25 m.

 This joint, according to the invention, is particularly intended for the production of walls molded in the ground.

Claims (11)

 1) Device for producing a joint between panels of diaphragm walls, characterized in that it comprises two flexible inflatable cells (3) on the sides of the frame (1), which can be pressurized alternately or simultaneously 9 with compressed air, the width of the deflated joint being narrower than the excavation of the wall.  2) Device according to claim 1 characterized in that the cells (3) are tensioned in circular housings (2) by means of screw tensioners (7).  3) Device according to claim 1 characterized in that the system for fixing the flexible cells on a slide (8) allows the extension of the cells for formwork.  4) Device according to claim 1 characterized in that the seal includes a reservation (18) allowing the establishment of waterproof profile to incorporate into the concrete  5) Device according to claim 1 characterized in that the seal comprises metal profiles (19) to allow the guidance of the bucket for the excavation of the adjacent panel.  6) Device according to claim 1 characterized in that the lower part of the joint comprises a metal nozzle (4) allowing its wedging at the bottom of the panel.  7) Device according to claim 1 characterized in that the cells are crushed by the hydrostatic pressure of the bentonite during the descent of the seal in the molded wall.  8) Device according to claim 1 characterized with regard to the possibility of wedging and laterally blocking the joint by inflation of the cells with compressed air over the entire height of the exca vation of the molded wall panels.  9) Device according to any one of the preceding claims, characterized in that the joint provides temporary sealing between two parts of panels of molded walls not yet concreted.  10) Device according to the preceding claims characterized in that the extraction of the joint is carried out after setting of the concrete.  11) Device according to the preceding claims, characterized in that the formwork is stripped by deflating and re-inflating the cells (3).