DE29716673U1 - Soil improvement device using powdery binder - Google Patents

Abstract

The appliance feeds a binding agent into especially cohesive grounds with high water content. it has a charging container (22) for the agent, with a charging aperture (26), and a ventilation aperture open to the surroundings. A feeder tube (23) connected to the bottom of the container has a discharge opening (34) near its lower end which is closed by a controllable closure device. A vibrator device (24) is positioned within the feeder tube near its lower end and a filling level sensor (41) is also located near the lower end. The feeder tube is elastically suspended from the material container.

Description

The invention relates to a method and a device for introducing powdered binding agent into the soil , in particular into cohesive soil with a high water content , for producing hardened consolidation columns in the soil to improve the load-bearing capacity of the soil.

DE 43 04 816 A1 discloses a device and a method for stabilizing soft subsoil using dry mineral powder, in which a pipe driven into the subsoil is used, which is guided inside a previously driven protective pipe and has a cone seat valve at the front end. The pipe filled with the powder to be introduced is driven into the ground with the valve closed and the valve is opened using a rod after the pipe has reached its lowest position; the powder is then pressed out of the pipe using compressed air while the pipe is pulled out and the resulting opening in the ground is filled. The compressed air exits the valve and is supposed to flow out along the outside of the pipe. This can lead to disruptions in the flow of air, which can cause defects in the consolidation column.

From DE 44 17 887 A1 a method and a device for increasing the strength of soft subsoil is known, in which the device has a screw arrangement within a pipe for removing soil material and for introducing powdery binding agent.

Defects in the solidification column are not to be expected, as the powder can be pressed out using the screw when the tube is pulled. However, the device is complicated and subject to wear and tear with regard to the screw drive.

Based on this, it is the object of the present invention to provide a method and a device which ensure an improved, operationally reliable implementation of the said method.

The method according to the invention is characterized in that the pulling of the lock pipe is interrupted when the binding agent level in the lock pipe falls below a lower minimum level.

In this way, defects in the solidification body to be created are safely avoided, as could occur due to uncontrolled, complete emptying of the lock pipe or due to defects in the fill level within the lock pipe as a result of bridges. After the vibrator pipe has been stopped, it can be completely filled with powdery binding agent. The lock pipe is preferably refilled whenever the fill level of binding agent in the lock pipe falls below an upper minimum. Filling is carried out by blowing in powdery binding agent, whereby the compressed air used for conveying can escape through a vent opening in the feed container. Filling is stopped when a maximum fill level in the feed container is exceeded. This feed container is usually permanently connected via a pipeline to a silo vehicle that has a compressed air conveying device and from which the refilling processes take place. The lock pipe is vibrated into the ground using known technology. When pulling the lock pipe to apply the binding agent, it can also be shaken to solidify the material.

The powdery binding agent can advantageously extract water from the cohesive soil, so that the load-bearing capacity of the cohesive soil is significantly improved. In addition, the introduction of the powdery binding agent causes material to be displaced in the soil, which leads to consolidation and thus to a further improvement in the load-bearing capacity. The consolidation and displacement of the soil simultaneously causes the soil water to be squeezed out, so that the binding agent can bind with the soil water and form a solidified column body.

The vibration of the lock pipe and the introduction of the binding agent under the soil surface after vibration while pulling the lock pipe can produce a consolidation column
with a larger diameter than the lock pipe.

The process is repeated in a known manner at intervals so that a grid of consolidation columns is created in the subsoil whose load-bearing capacity is to be improved.

A device according to the invention comprises a feed container for powdery binding agent with a feed opening and a vent opening, a lock pipe which is connected to the bottom of the feed container, with an outlet opening at the lower end, and a vibrating device near the lower end of the lock pipe, which lies within the cross section of the lock pipe, and at least one level sensor near the lower end of the lock pipe. In particular, the device comprises a further level sensor near the upper end of the lock pipe and in the feed container. The device is preferably attached to a leader which is mounted on a tracked vehicle. The powdery material is filled into the lock pipe before it is vibrated. The weight of the material supports the vibration of the lock pipe.

After the complete shaking, the locking device is opened and the pulling of the lock tube begins, whereby powdery binding agent flows out of the lock tube essentially without pressure. The filling level sensors according to the invention ensure that the pulling stops and the locking device is closed.
Closing device in the event of an uncontrolled complete emptying of the lock pipe or in the event of defects in the filling level, which can occur due to bridging. As soon as the filling level sensor at the lower end of the lock pipe indicates the empty state , ie the filling level falls below the sensor, the device is pulled
interrupted to avoid incorrect fillings in the resulting
A stoppage of this kind triggers a refilling of the lock pipe from a silo vehicle connected to the feed container. Bridge formations can be overcome by the weight of the refilled, powdery binding agent or the slight overpressure generated by the compressed air used to blow in the binding agent. The refilling process is interrupted when the level sensor in the feed container is reached and usually starts again when the level falls below the upper level sensor in the lock pipe. The feed container serves to calm the flow in the area used for blowing in
powdery binding agent into the lock pipe and for blowing off this compressed air, which consequently cannot reach the solidification column. The vent opening of the feed container is preferably provided with a dust filter. The lock pipe is particularly elastically attached to the feed container. The feed opening of the feed container is provided with a hose connector for connecting a hose line from a silo vehicle.

In order to prevent soil material from entering the lock pipe when it is vibrated, the lock pipe should preferably be provided with a plug made of gravel or similar below the closing device by first lowering the device into a gravel heap on the ground surface. This is not necessary if the closing device is provided directly at the end of the lock pipe.

The vibrating device is advantageously located at the lower end of the lock pipe within its cross-section; the free flow cross-section of the lock pipe for powdery material is thus reduced in this area.

The lock pipe can be elastically attached to the feed container so that the feed container is protected from the vibrations of the
The lock pipe is disconnected during vibration. This prevents unwanted compaction of material in the feed container.

The closing device at the lower end of the lock pipe is preferably located at a distance from the outlet opening directly above the vibrating device.

The locking device of the lock tube can be designed in the form of a slide, a flap or a pneumatic pinch valve device. The same applies to the additional locking device at the lower end of the lock tube.

At the lower end of the feed container, a further closing device can be provided, which allows the lock pipe to be refilled several times from the feed container if a connection to the silo vehicle cannot be maintained permanently.

The entire device can preferably be moved via a guide carriage on a leader that is directly attached to the feed container.

A preferred embodiment of the invention is explained below with reference to the drawings.

Fig. 1 shows a device according to the invention in vertical section, attached to a leader with a supporting crawler shown in thin lines;

Fig. 2 the closing device of the lock tube in a first embodiment;

Fig. 3 the closing device of the lock pipe in a second embodiment;

Fig. 4 the closing device of the lock pipe in a third embodiment.

In Figure 1, a tracked vehicle 11 with a vertically erected leader device 12 attached to it is shown in thin lines. The tracked vehicle 11 stands on the ground surface 13. A device 21 for introducing powdery material under the ground surface to produce essentially vertical columns hangs on the leader device 12 in a substantially vertical position. A feed container 22, a lock pipe 23 and a vibrating device 24 can be seen as essential components on the device 21. The feed container 22 is guided on the leader 12 by means of a two-part slide 25. The lock pipe 23 is also elastically suspended on the lower part of the slide 25. The feed container 22 has a feed nozzle 26 which runs tangentially into the feed container 22 and to which a hose connection from a silo vehicle can be connected.

A sheet metal hood with a dust filter 27 is placed on the feed container 22. The feed container 22 ends at the bottom in a
Funnel 28 which ends in a straight nozzle 29. This is connected to an expanded inlet area 31 of the lock pipe 23 via an elastic connecting piece 30. At the lower end of the lock pipe, its internal cross-section is reduced by the installation of the vibrator 24. At the entrance to the area with reduced cross-section, a closure plug 32 is shown in the closed position and in thin lines in the open position. The lock pipe 23 ends in a conical section 33 with an outlet opening 34. In the cross-sectional view, the round cross-section of the feed container 22 and the oval cross-section of the lock pipe 23 are shown on the side. A total of three fill level sensors are provided on the device, namely a first fill level sensor 39 in the feed container 22, which can indicate the "fully filled" state for the feed container, a second fill level sensor 40 at the upper end of the lock pipe 23, which can indicate the "fully filled" state for the lock pipe 23 or "fully emptied" state for the feed container 22, and a third fill level sensor 41 at the lower end of the lock pipe, which is intended to indicate the "fully emptied" state for the lock pipe 23.

Figure 2 shows a section of the lock tube 23 with the upper end of the vibrating device 24. An installation in the lock tube forms a transition funnel 35. The closure plug 32 with conical seat can be seen here in the closed position in solid lines and in the open position in dashed lines as in Figure 1. An actuating mechanism is not shown in detail. A vertical actuating rod with a corresponding actuating cylinder located outside or inside the lock tube is suitable for this.

In Figure 3, a section of the lock pipe 23 with the upper part of the vibrating device 24 can be seen. Above

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The vibrating device has a pivoting flap mechanism 36, which is shown in solid lines in the open position and in dashed lines in the closed position. A vertical actuating rod and an actuating cylinder located outside or inside the lock tube can serve as actuating means in the same way as previously described.

In Figure 4, a section of the lock pipe 22 and the upper part of the vibrating device 24 can also be seen, as well as a sheet metal installation that forms a support surface 37. An elastic air bag 38 is built onto the support surface, which together with the wall parts forms a pneumatically actuated pinch valve. A compressed air line must be provided along the lock pipe for actuation.

Closing devices of the type shown in Figures 2 to 4 and described here can also be installed in the transition cone 28 of the feed container 22.

Claims (9)

1. Device for introducing powdered binding agent into the soil, in particular into cohesive soil with a high water content, to produce hardened consolidation columns in the soil to improve the bearing capacity of the soil, full a feed container (22) for powdered binding agent, with a feed opening (26) and a vent opening opening to the environment, a lock pipe (23) which is connected to the feed container (22) at the bottom, with an outlet opening (34) near the lower end which can be closed with a controllable closing device, and a vibrating device (24) near the lower end of the lock tube (23) which lies within the cross-section of the lock tube (23), and at least one level sensor (41) near the lower end of the lock pipe (23). 2. Device according to claim 1, characterized by a level sensor (40) near the upper end of the lock pipe (23) · 3. Device according to claim 1, characterized by a level sensor (39) in the feed container (22) near the upper end of the lock pipe (23) 4. Device according to claim 1,
characterized, that a guide carriage (25) is arranged on the feed container (22) and can be moved on a leader (12). 5. Device according to one of claims 1 to 4, characterized in that the lock pipe (23) is elastically attached to the feed container (22). 6. Device according to one of claims 1 to 5, characterized in that that the feed opening of the feed container (22) is provided with a hose connector (26). 7. Device according to one of claims 1 to 6, characterized in that a dust filter (27) is provided in the ventilation opening on the feed container (22). &bull;·&Phi; 8. Device according to one of claims 1 to 7, characterized in that the closing device (32, 36, 38) is provided at the lower end of the lock tube (23) at a distance from the outlet opening (34) immediately above the vibrating device (24) · 9. Device according to one of claims 1 to 8, characterized in that a further closing device is provided at the lower end of the feed container (22).