EP0203242A1 - Method and device for continuously lining a subway - Google Patents

Abstract

The method according to the invention makes use of a lining structure comprising lining frames or arches (C1 to Cn) placed next to the wall. It employs felt sleeves of three-dimensional texture (M1 to Mn-1 which are placed on the lining structure in the space between the structure and the wall. Injected into these sleeves is a cement slurry having a water/cement ratio of the order of 0.6 and containing an additive capable of accelerating its setting, whilst at the same time giving it good mechanical strength. The method according to the invention makes it possible to ensure a continuous and uniform blocking of the earth over the entire periphery of the arch, frame or the like. <IMAGE>

Description

The present invention relates to a method and a device making it possible to provide continuous support for an underground passage, by means of a support structure involving elements such as support frames or hangers placed near the wall of the underground passage.

To ensure the continuity of the support throughout the structure, this method uses a sleeve which is placed on the support structure, in the space between said structure and said wall. It then consists in filling this sleeve with a compound based on cement and water which makes it possible, as a result of the setting of the cement, to block the ground over the entire periphery of the support structure.

Processes of this kind have already been proposed which consist in injecting mortar into fabric sleeves by means of pumps, of the concrete pump type. However, it turns out that due to the composition of the mortar and the injection pressure used, it is not possible to fill the sleeve homogeneously. Furthermore, it is necessary to use sleeves of relatively resistant material and specially woven to avoid the risk of tearing of the sleeve during the injection. In addition, the application of the sleeve on the ground is not always carried out in a homogeneous manner due to the phenomena of shrinkage of the mortar during setting, which are mainly due to the evaporation, through the fabric, of a fraction of the water making up the mortar.

The invention therefore aims to eliminate these drawbacks. It proposes a process which also allows, thanks to the nature of the handle and the composition of the cement compound used, the use of low pressure pumps which are less important (in particular in weight, volume and cost) than concrete pumps. conventional and which, however, contrary to what one could foresee, allows to obtain a good homogeneity of the application of the sleeve on the ground as well as an accelerated setting of the cement accompanied by a very good mechanical resistance.

In a similar manner to the previously mentioned prior methods, this method for producing a continuous support in an underground by means of a support structure comprising elements such as frames or support hangers placed near the wall of the underground, involves a sleeve, made of water permeable material which is placed on the support structure, in the space between said structure and said wall, and into which is injected a cement-based compound which , as a result of its grip, allows the ground to be blocked at the periphery of the support structure.

According to the invention, this process is more particularly characterized in that the cement-based compound consists of a cement slurry having a water / cement ratio suitable for allowing its injection into the sleeve by means of a low pressure pump, of the order of 4 to 6 bars, this grout further comprising an adjuvant capable of accelerating its setting while quickly giving it good mechanical strength, and in that said handle is made of felt with three-dimensional texture and high filtering power allowing rapid extraction of excess water from the grout during injection, while ensuring retention inside the sleeve of the cement and the adjuvant.

It clearly appears that thanks to the nature of the grout, the pressure at which it is injected and the absence of aggregates which risk causing tears, the required mechanical resistance of the sleeve allows the use of a material (felt ) particularly well suited for ensuring rapid removal of excess water from the grout during injection, so that there will then remain in the grout only the amount of water necessary to ensure the setting of the cement and only this will avoid shrinkage phenomena.

Advantageously, the adjuvant used may consist of a powder such as a powder of volcanic rock.

• - 50% de ciment
• - 17% d'adjuvant
• - 33% d'eau

Furthermore, the water / cement ratio of the grout used will preferably be around 0.6, the percentage composition of this grout can then be:

• - 50% cement
• - 17% adjuvant
• - 33% water

• - la foration et le minage ou le creusement mécanisé d'un tronçon de souterrain ;
• - la purge du souterrain avec, au besoin, l'équarrissage de la couronne ;
• - la pose des chapeaux des cadres avec les entretoises et les panneaux de grillage ;
• - la mise en place de coussins pneumatiques sur les entretoises au moins entre le dernier et l'avant dernier chapeau ;
• - la mise en place et la fixation des manches sur les chapeaux, excepté le dernier à front ;
• - l'évacuation des déblais de la partie basse de la galerie ;
• - la pose des pieds avec les entretoises et les panneaux de grillage ;
• - la mise en place et la fixation des manches sur les pieds ;
• - le remplissage des manches par injection d'un coulis ; et
• - la récupération des coussins pneumatiques à l'arrière des manches injectées.

The invention also relates to a method in accordance with that described above, in which the support structure is composed of frames, hangers or the like, each comprising caps and feet connected by spacers, with, between each of the frames, panels of roasting, this process being more particularly characterized in that it comprises the following stages:

• - drilling and mining or mechanized digging of an underground section;
• - the purging of the underground with, if necessary, the rendering of the crown;
• - fitting the hats of the frames with the spacers and the mesh panels;
• - the installation of pneumatic cushions on the spacers at least between the last and the penultimate hat;
• - the fitting and fixing of the sleeves on the hats, except the last one with a brow;
• - the removal of spoil from the lower part of the gallery;
• - fitting the feet with the spacers and the mesh panels;
• - the installation and fixing of the sleeves on the feet;
• - filling the sleeves by injecting a grout; and
• - the recovery of the pneumatic cushions at the back of the injected sleeves.

• Les figures 1 à 3 sont trois coupes longitudinales schématiques d'une galerie en cours de creusement, ces figures illustrant trois phases successives du procédé selon l'invention, à savoir : la phase précédant la foration et le tir (figure 1), la phase de pose des chapeaux des cadres de soutènement (figure 2), et la phase de mise en place des manches sur les cadres et d'injection du coulis de ciment dans ces manches (figure 3).

Embodiments of the invention will be described below, by way of nonlimiting examples, with reference to the appended drawings in which:

• Figures 1 to 3 are three schematic longitudinal sections of a gallery during digging, these figures illustrating three successive phases of the method according to the invention, namely: the phase preceding drilling and firing (Figure 1), the phase of fitting the caps of the support frames (Figure 2), and the phase of placing the sleeves on the frames and injecting the cement slurry into these sleeves (Figure 3).

More precisely, in FIG. 1, only the end of the gallery 1 close to the front 2 has been shown. This gallery 1 is equipped with a support structure comprising a plurality of transverse frames C _l , C ₂ , C ₃ , C _n-1 , C _n connected to each other by spacers of which only the upper spacer E or carrier has been shown. Each of these frames C ₁ ..., C _n comprises a curved upper part or cap CH ₁ ..., CH on which removable feet P ₁ , P _n are fixed. On each of these frames, except the last (n), is placed a sleeve M ₁ , M _n-1 into which a cement grout has been injected which ensures a homogeneous mechanical connection between the frame and the wall of the underground. Mesh panels G ₁ , G2, G _{n-1 '} with suitable meshes, are placed between the frames C ₁ , C _n-1 to prevent the falling of small blocks.

As can be seen in this figure, due to the fact that the sleeves M ₁ , M _n-1 carry out a continuous blocking of the ground over the entire periphery of the frames C ₁ , C _n-1 , it is not possible to set up a sleeve on the last front frame C _n , because it is necessary to be able to thread the spacers E and the mesh panels G on this frame C _n , during the next advancement.

In addition, to avoid a disintegration of the terrain above the last frame C _n and to control the off-profile, the terrain is temporarily supported by two or three pneumatic cushions C _p1 placed on the spacers E between the last C _n and l '' penultimate C _n-1 frames. These pneumatic cushions C _p1 are only removed when the sleeve M _n is injected into the frame C _n which was the last at the front, before the next advancement.

A partir de l'état du souterrain illustré sur la figure 1, la première étape, en vue de son avancement, consiste en une foration du front 2 et un minage sur une longueur 1 d'environ lm50.For example, two types of cushions C _p1 can be used, namely the cushions V ₁₂ and V ₁₈ sold by the company Draeger-Brand, the characteristics of which are provided below in the following table:

From the state of the underground illustrated in FIG. 1, the first step, with a view to its advancement, consists in drilling the front 2 and mining over a length 1 of around lm50.

After having carried out the shooting of the volley, one carries out a first purge of the upper part of the gallery and, if necessary, a squaring of the crown with the jackhammer.

During the next step, the caps CH _{n + 1 ′} CH _{n + 2} are applied with the spacers E and the mesh panels G _{n + 1} , G _{n + 2} . Pneumatic cushions Cp _{2 are then placed} on the spacers E between the last CH _{n + 2} and the penultimate CH _{n + 1} caps. At the end of this stage, the underground is in the state illustrated in Figure 2.

We then proceed with the installation and fixing of the sleeves M _n , M _{n + 1} on the caps CH _n , CH _{n + 1 '} except on the last hat with front CH _{n + 2'} then we remove the cuttings D from the lower part of the underground. The feet P _{n + 1 ′} P _{n + 2 are then placed} with the spacers P and the mesh panels G, then the positioning and fixing of the sleeves on the feet P _{n ′} P _{n + 1 ′} P _{n + 2} (Figure 3). The next step consists of filling by injection of the sleeves M _n , M _{n + 1} .

Once the cement grout has been set, the pneumatic cushions C _p1 , Cp ₂ located behind the injected sleeves M _n , M _{n + l} can be recovered.

As previously mentioned, the handles M used by the method according to the invention are made of felt with three-dimensional texture, for example a non-flammable needle felt of the type described in French patent application No. 79 25724, filed on October 10, 1979, on behalf of the Company DOLLFUS ET NOACK. Such a felt indeed has a high filtering power and therefore allows excess water to flow from the grout during injection while retaining, at the inside of the sleeve, the cement and the adjuvant. These sleeves also include, sewn on their lower periphery, straps of suitable length to allow attachment by lacing on the frames. They also include, sewn in their middle part or at their ends, filling sleeves, possibly made of felt.

For example, the main handles can have a diameter of 250 mm or more and the filling sleeves, a diameter of about 90 mm.

• 1) un ciment classique CPH ou CPJ selon les normes actuellement en vigueur ;
• 2) un adjuvant à base de poudre de roche volcanique ;
• 3) de l'eau.

Regarding the cement grout used, this grout has three components, namely:

• 1) a classic CPH or CPJ cement according to the standards currently in force;
• 2) an adjuvant based on volcanic rock powder;
• 3) water.

As previously mentioned, to obtain a perfectly pumpable grout, despite a certain smoothness, the water / cement ratio is of the order of 0.6.

dans ce cas, le rapport eau/ciment vaut 0,644.Thus, for example, the composition of a m ³ of grout suitable for implementing the method according to the invention can be as follows:

in this case, the water / cement ratio is 0.644.

The invention is not limited to this single example, the proportions indicated being able to vary considerably depending on the case. The grout injected into the sleeve under a pressure of a few bars, freezes after a few tens of minutes (normal duration 30 minutes) and rises very quickly in resistance (15 to 20 bars at 18 hours, 50 bars at 24 hours, 150 bars at 7 days, with changes of more than 220 bars after 10 days).

In a manner analogous to the previously mentioned prior methods, the method according to the invention achieves a continuous blocking of the ground over the entire periphery of the hanger, frame or other, and makes it possible to restore the compression stresses at any point of the perimeter of the gallery .

It saves the intermediate elements of traditional support between hanger, frame or other, which are more or less effective (mesh more stone lining or other, very costly in labor).

This process, implemented immediately after the installation of hangers, frames or the like, requires simple equipment, compact and quick to implement and makes it possible to improve the digging and support speeds in difficult terrain.

The whole implementation with simple materials and easily adaptable grouts, is perfectly compatible with the traditional support workforce.

Claims (10)

1. A method for producing a continuous support in an underground by means of a support structure comprising elements such as frames or support hangers placed near the wall of the underground, this method involving at least one handle made of water permeable material which is placed on the support structure, in the space between said structure and said wall, and into which is injected a cement-based compound which, as a result of its setting, allows the ground to be blocked at the periphery of the support structure, characterized in that said compound consists of a cement grout having a water / cement ratio suitable for allowing its injection into the sleeve (M ₁ to Mn + 1) by means a low pressure pump of the order of 4 to 6 bars, this grout further comprising an adjuvant capable of accelerating its setting while giving it good mechanical resistance, and in that said handle (M ₁ to M _{n +1} ) is performed in one felt with three-dimensional texture and high filtering power allowing rapid extraction of excess water from the grout during injection while ensuring retention inside the sleeve of the cement and the adjuvant. 2. Method according to claim 1, characterized in that the water / cement ratio of the grout is approximately 0.6. 3. Method according to one of claims 1 and 2, characterized in that the above adjuvant is based on volcanic rock powder. 4. Method according to one of the preceding claims, characterized in that the grout has the following composition:

5. Method according to one of the preceding claims, characterized in that the aforesaid felt with three-dimensional texture is needle felt. 6. Method according to one of the preceding claims, in which the support structure is composed of frames (C ₁ , C _n ) each comprising caps (CH ₁ , CH _{n + 2} ) and feet (P ₁ , P _{n +2} ) connected by spacers (E) with, between each of the frames, mesh panels (G _l , G _{n + 2} ), characterized in that it comprises the following stages: - drilling and mining or mechanized digging of an underground section; - the purging of the underground with, if necessary, the rendering of the crown; - fitting the caps (CH _{n + 1} , CH _{n + 2} ) of the frames (C _{n + 1} , C _{n + 2} ) with the spacers (E) and the mesh panels (G _{n + 1} , G _{n + 2} ); - the installation of pneumatic cushions (Cp ₂ ) on the spacers (E) at least between the last and the penultimate cap (C _{Hn + 2} , CH _{n + 1} ) (Figure 2); - the fitting and fixing of the sleeves (M, M _{n + 1} ) on the caps (CH _n , CH _{n + 1} ) except the last one at the front (CH _{n + 2} ); - the removal of spoil from the lower part of the gallery; ^- fitting the feet (p _{n + 1} , p _{n + 2} ) with the spacers ( _E ) and the mesh panels; - placing and fixing the sleeves on the feet (P _{n + 1} , P _{n + 2} ); - filling the sleeves by injecting a grout, and - recovery of the pneumatic cushions (CP,) at the back of the injected sleeves (M _{n + 1} ). 7. Device for implementing the method according to one of the preceding claims, characterized in that it comprises a felt sleeve (M ₁ to M _{n + 1} ) with three-dimensional texture. 8. Device according to claim 7, characterized in that said sleeves comprise, sewn on their lower periphery, straps of length adapted to allow fixing by lacing on the support structure. 9. Device according to one of claims 7 and 8, characterized in that said sleeves (M ₁ to M _{n + 1} ) further comprise, sewn in their middle part and / or at their ends, possibly filling sleeves in felt.

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