JPH11315695A - Method for pressing-in mortar into ring space between lining and rock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for pressing-in mortar capable of pumping mortar for several hours and achieving the minimum shearing strength in a short time. SOLUTION: This method is for pressing mortar into a ring space between lining and rock at the time of shield propulsion of a tunnel covered with the lining through a hose by pumping a mortar mixture from a mortar vessel 9 provided in a following device 8. In this case, the mortar can achieve the purpose for installing a lining pipe withstanding a pressure and a propulsion force. However, thixotropy agent and lime sandstone powders are added to the mortar mixture at such amount that rapid initial shearing strength of 5 to 10 KN/m<3> is achieved after 30 minutes and restart of pumping by slight pressure up to about 8 bar after the stop due to operation conditions is guaranteed to guarantee pumping start ability after the stop for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lining, in which a mortar mixture is inserted into an intermediate space from a mortar container mounted on a follower via a hose and preferably on a reinforcing strip mounted on the periphery of the shield. To inject mortar into the ring space between the lining and the rock during the shield propulsion of the tunnel covered by the mortar.

[0002]

2. Description of the Related Art A hollow space is formed between a lining and a rock because a larger hollow space needs to be generated for a lining shell when a tunnel shielded by a lining is propelled. The space is
The mortar must be pressed, which installs a tunnel in the rock and undertakes the pressure and propulsion transmission between the lining and the rock.

The mortar is then subject to three basic requirements: the first one is to be able to fulfill the purpose of installation to withstand the pressure and propulsion of the lining tube. Quick curing starts. The liquid properties of the mortar must vanish rapidly and a shear strength must be formed. Because the liquid mortar absorbs the load of the lining's own weight and in another installation the load on the traveling mechanism of the follower with the mortar storage container and the pump, and the load may cause deformation of the lining ring. .

[0004] The second requirement is a good flow capacity so that the hollow space can be completely filled.
The third requirement is a longer working capacity of the mortar.
The mortar is mixed and pumped into a storage container, where it is maintained by movement by a stirring mechanism, and from here is pressed into the ring space through a hose conduit and a reinforcing strip. In reinforced strips, specially shaped tubes are problematic, which are welded in a straight line around a shield tail, usually made of solid steel.

The press-fitting takes place continuously during propulsion over the width of the lining ring (approximately 1 to 2 m). After longer interruptions of up to approximately 1.5 hours, pumping restart of the mortar must still be possible without having to apply too high a pump pressure.

[0006] To meet these three conflicting requirements, different mortar mixtures with different cement contents have been used. Thereby, sufficient flow capacity and pumping capacity can be achieved. By the initiation of the curing of the binder, only the consistency, i.e. the flow capacity, is reduced within the first time. No shear strength is thereby configured. The strength gradually develops only after hydration of the binder, after a few hours to several months. The required shear strength after 30 minutes,
Cannot be achieved. Depending on the cement content, a more or less powerful onset of curing takes place. All commonly used mixtures age slightly during the processing time, but they do not require high pressure upon pumping restart, since no shear strength has yet been formed.
Attempts to accelerate hardening by additives such as, for example, water glass, have again shown the problem of the ability to restart pumping after longer stops.

[0007]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method in which the mortar can be pumped over several hours and is therefore workable, but nevertheless achieve a minimum shear strength in a short time. In other words, a press-fitting method as described in (1) is constituted.

[0008]

The set object is solved by the present invention as follows by the method described above. That is, the thixotropic agent and lime sandstone powder are added to the mortar mixture in such an amount that a rapid initial shear strength due to thixotropy, good flow capacity and pumping restart with slight pressure after shutdown due to operating conditions are guaranteed. .

Due to the thixotropic action, the mortar only begins to harden, rather than harden, and when pumped again after an interruption, based on the lubricating action of the lime-sandstone powder, It is possible to fluidize again the entire content of the reinforcing strip. According to the present invention, the pressure peak during pumping restart is reduced, and thus the difficulties caused by thixotropy are:
It is buffered again.

On the contrary, the high lubricating ability of lime sandstone is
To the mortar mixture, it is possible to add grinding sand and crushed stone as another additive, whereby the initial shear strength can be further increased, but nevertheless, after almost one hour, Pumping restart is enabled.

Preferably the additives to the mortar are chosen such that a shear strength of 5 to 10 KN / m * 2 is achieved after about 30 minutes. This ensures that the mortar has sufficient load capacity during the course of propulsion when the ring is completely out of the shield tail and the propulsion is fully effective.

[0012] as possible mortar mixture has a composition as follows: the cement up to 500 kg / ^{m 3,} the smoke dust to ^{900kg / m 3, 400kg / m} 3
Water up to 20 kg / m ³ thixotropic agent, 40
Lime sandstone powder up to 0 kg / m ³ , 1500 kg / m ³
Sand at 5 kg / m ³ fluidizer.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows that rock is driven into a rock 1 by shield propulsion.
It shows that a substantially circular hollow space 2 is driven into which a lining 3 is to be incorporated, with a ring space 4 remaining between the back of the hollow space 2 and the lining, filled with mortar. The diameter of this ring space which has to be larger than the outer diameter of the lining.

How this is done is illustrated schematically in FIG. Here, it is clear that the cutting head 5 arranged in the shield propulsion device proceeds to form a hollow space in the rock, into which the lining ring 6 is incorporated during the progress of the shield propulsion. . At this time, since the last lining ring 6a is still tightened in the shield peripheral surface 7, this stays at a distance from the boundary of the dug ring space as the shield propulsion proceeds. I have. During the progress of the shield propulsion, the mortar was welded from a container 9 mounted on the follower to the press-fitting conduit 10 and the shield circumference via a so-called follower 8 running on the inner bottom of the already machined lining. It is pressed into the ring space 12 via the reinforcing strip 11, which is
It is formed between the embedded lining 6a and the rock. This press-fit mortar is connected to the already hardened mortar in the ring space 13 between the rock and the already installed lining 6.

With the additive according to the invention to the press-in mortar, it is possible to ensure that the just-pressed lining ring 6a is well supported and subsequently to perform a pumping restart with the dominant pump pressure after the installation of the next lining ring. It is guaranteed that you can.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a tunnel covered by a lining.

FIG. 2 is a schematic longitudinal sectional view showing a shield propulsion device used for press-fitting a ring space between a lining and a rock.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rock 2 Hollow space 3 Lining 4 Ring space 5 Cutting head 6 Lining ring 7 Shield peripheral surface 8 Follower 9 Container 10 Press-fitting conduit 11 Reinforcement strip 12 Ring space 13 Ring space

Continued on the front page (72) Inventor Marx Theeves Lal-Fouyerveersle-Jutlase 52, Germany

Claims (5)

[Claims] 1. A lining-covered tunnel in which a mortar mixture is inserted into an intermediate space via a hose by pumping from a mortar container mounted on a follower and at a reinforcing strip mounted on the shield circumference. Mortar is injected into the ring space between the lining and the rock during the propulsion of the shield by rapid initial shear strength due to thixotropy, good flow capacity and pumping restart with slight pressure after stopping due to operating conditions. A method of forcing mortar into a ring space between a lining and a rock, characterized in that a thixotropic agent and a lime-sandstone powder are added to the mortar mixture in a guaranteed amount. 2. The mortar mixture according to claim 1, further comprising ground sand and crushed stone.
The method described in. 3. The addition of the mortar is such that a shear strength of 5 to 10 KN / m ² is achieved after 30 minutes and the pump pressure at the restart of the pumping of 8 bar is not exceeded. The method according to claim 1 or 2, wherein 4. The process as claimed in claim 1, wherein the crushed sand has a particle size of 0 to 2 mm and the crushed stone has a particle size of 2 to 5 mm. 5. The mortar mixture has the following composition: up to 500 kg / m ³ of cement, 900 kg / m
smoke dust of up to m ^3, water of up to 400kg / ^{m 3,} 20k
thixotropic agents to g / ^{m 3,} lime sandstone powder to 400 kg / ^{m 3,} grinding sand to 1500 kg / ^{m 3,}
Fluidizing agent to 5 kg / m ^3, characterized in that, the mortar mixture for the process according to one of claims 1 to 4.