ES2213524T3 - PROCEDURE FOR THE SOIL IMPROVEMENT BY CAL COLUMNS. - Google Patents

Abstract

The method involves supplying a dry binder through a sink pipe (11) sunk into the ground. The sink pipe has a cylindrical cladding pipe (12), an inner pipe (13) and a flap (17) at its lower end. The sink pipe is driven vertically into the ground to a predetermined depth, with the flap closed. The inside of the cladding pipe is supplied with dry binder, and at the same time air is drawn from the lower end of the pipe up through the inner pipe. After the cladding pipe has been filled to a partial height with dry binder, the sink pipe is drawn from the ground with the flap open, while further binder is supplied, so that a column of dry binder is left in the ground. An Independent claim is included for a device for implementing the method.

Description

Procedure for soil improvement through lime columns

The present invention relates to a procedure for soil improvement by providing a Dry binder through a tube, previously driven into the floor, which has a cylindrical casing tube and a valve hinge located at the lower end of the casing tube. Further, The present invention relates to a device for Performing this procedure.

Various procedures for improvement are known of the soil in which the binders are injected into the soil to various depths from the inflated injection tubes on the floor. Procedures for the manufacture of concrete columns prepared on site, in which an empty tube driven into the ground with a closed flap valve located below, it is filled with concrete and then extracted with the open flap valve thus generating the concrete column prepared on site For this purpose you can refer to the document CH-PS 538 573 and document DE 41 37 541 A1.

EP 0 903 440 A2 discloses a procedure and a device for soil improvement by powder binder. According to this, the binder is insufflated to pressure by a loading hopper in a sluice tube, arranged in the upper end of this tube. By the lower end of the tube sluice, in which a vibrator is arranged, the binder It comes out of the sluice tube. The compressed air used for the insufflated from the binder is insufflated through the loading hopper, that is, before the sluice tube, whereby the air flow Inside the sluice tube is small.

Document DE 41 25 576 A1 discloses a procedure for pressure injection of dust in soils soft, in which first volume powder is provided increased air pores and then by air tablet is injected under pressure into the ground through tubes thin The bypass of compressed air is not discussed.

The present invention is based on the objective of provide a procedure for soil improvement, with which both embankments and formations of natural terrain persistently. The solution consists of a procedure with the following sequence of stages: the tube is driven with the flapper valve closed, vertically inside the ground to a certain depth, the dry binder is introduced inside the envelope tube; after filling the tube wrap up to a partial height with dry binder, removed the pipe driven into the ground along with the flapper valve that opens and continues to introduce dry binder, which forms a column of dry binder inside the soil, and the binder dry is blown into the enclosure tube by compressed air as a carrier element, while simultaneously at the end The lower part of the casing tube exits air from the top of a inner tube that runs longitudinally inside it. The filling of the wrapping tube takes place especially halfway of its height, before it is extracted. Meanwhile the air can be sucked from the surrounding tube through the inner tube, while the binder is in a fluidized state strongly enriched with air.

The device according to the present invention it comprises a tube to be driven into the ground, consisting of a tube cylindrical casing and a flap valve arranged in the lower end of the envelope tube, in which the envelope tube is attached at its upper end with a device for transport of the dry binder, and in the envelope tube there is provided a compressed air generator or a fan for the transport of the dry binder by means of compressed air as a medium carrier, and an inner tube that runs longitudinally inside of this one ends with its free bottom end inside the tube envelope and with its upper end comes out of the envelope tube to the environment. The inner tube may be particularly connected with a vacuum for the air intake of the tube envelope

In the application of the procedure according to the The present invention is especially provided that previously mark on the floor surface a modular grid with a grid size of especially 15 to 100 cm, in which each Reticular point determines the position of a column. The diameter outer casing tube essentially corresponds to final diameter of individual columns from 100 to 200 mm particularly. After you have previously drawn a modular grid on the floor surface, are made in each Point the following manipulations of the process. Through Known handling utensils are introduced under pressure, or by vibration or impact the tube to penetrate the ground, with the flapper valve closed, until its lower end has reached the required depth, but the upper end still protrudes from the soil surface. Once reached the final depth dry binder is introduced into the tube envelope, and through the inner tube air can escape simultaneously, or be aspirated, respectively. The contribution of Dry binder can take place by means of a pump or a appropriate fan, then compressed air acting as half carrier. Compressed air can also be introduced here on impulse. Through the inner tube the compressed air has to distend, or eventually be aspirated for compaction of the dry binder, but the joint aspiration of the binder It has to be avoided to a noteworthy extent. When the wrapping tube is filled to at least a partial height, for example halfway, it is slowly pulled up out from the ground, whereby the flapper valve opens automatically or forced open, and the binder dry remains inside the ground like a column of a diameter relatively small The device is then moved to another point of the modular grid and the process is repeated. For this It is especially advantageous if lime is used as a dry binder and / or cement.

The mode of action of the lime and / or columns cement, ie dry hydraulic binders, consists of the case of quicklime CaO

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in a reaction of hydration (formation of Ca (HO2)) that can be very exothermic and it manifests itself in a decrease in the water content of the I usually;

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a modification of soil geotechnical properties by ion fixation of calcium and flocculation of clay particles, which manifest in an increase in shear strength and a decrease of compressibility;

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a modification of the structure of the clay due to the formation of aluminates and silicates of calcium hydroxides.

In case of the use of cement the effects they are less pronounced; but on the contrary, in case of presence of water, the reaction is much faster here. To combine both Effects can be operated with a mixture of lime and cement.

The effect of the driven tube has several aspects, that is the displacement of the soil for the formation of a hollow space when driving the tube, then the introduction of the lime or of the cement in the hollow space with a provisional tubing simultaneous hollow space inside the ground and finally the formation of the binder column in the ground when removing the swollen tube

Removal of the driven tube can be done continuously or in stages, with a predetermined speed, and here the extraction speed can be adapted to the eventually still persistent binder conduction.

Normally the tube to be hung hangs from the driving hammers of a crawler vehicle, whose carriages Guide are provided with equipment for the driving of columns.

The driver of the tracked vehicle can supervise and govern the inclination of the driving hammers, the penetration depth and quantitative lime flow or cement added.

The present invention will be described in more detail on the basis of the accompanying drawings.
cough:

Fig. 1 represents a tube to be driven according to the present invention in vertical section;

Fig. 2 represents a first stage of the method according to the present invention;

Fig. 3 represents

a) a second stage

b) a third stage

c) a fourth stage

of the method according to the present invention, with a crawler vehicle fitted with hammers in each case;

Fig. 4 represents parts of the installation of the device according to the present invention.

Figure 1 shows a tube to be driven 11 in vertical position according to its use. This one includes a tube cylindrical shell 12 and an inner tube 13 of smaller diameter than runs longitudinally within it, which is open by its bottom and ending free a short distance from the end of the casing tube 12. The means for holding the inner tube 13 inside the tube 12 are not represented here for the sake of Simplicity The tube to be driven 11 has at its upper end a head 14, which serves as an attack element so you can attack it a few column hammers. Under head 14, the tube envelope 12 has a first lateral tubing 15, through which is introduced by insufflated dry binder into the tube envelope The inner tube 13 has at its upper end under of head 14 an elbow 16 that goes outside through the wall of the envelope tube through which the displaced air can escape outside the casing tube 12, or air can be drawn from the tube interior 13 and with that of the envelope tube 12, as is indicated by symbols. At its lower end the tube envelope has a flapper valve 17 which when pushed into the ground can close the envelope tube while removing from the I ground the swollen tube, this flapper valve can be opened by itself, so that a current can flow from the surrounding tube of dry binder, which is indicated by an arrow 18. The outer diameter of the casing is characterized by d_ {m}.

Figure 2 shows a sector of a surface of a soil, seen in perspective, on which shows a modular grid 21, whose crossing points in two perpendicular directions to each other are separated from each other for the same unit distance a. In a part of the points of the reticle are visible columns 22 already finished, two of which they are represented in vertical section; these have a diameter of column d_ {s}.

A section is shown in figure 3 vertical through an upper layer of soil. On floor surface 31 sits a tracked vehicle 32. This one It has a 33 vertical hammers in a vertical position, with a carriage 34. Attached to carriage 34 is a pipe to be driven 11, which has already been previously described. A flexible tube 35 goes to the vehicle on tracks, and reaches the upper end of the tube to be driven eleven.

In figure 3a five can be recognized columns 22 finished. For the formation of another column, it is pushed or the tube to be driven is driven exactly at the distance of the grid, as represented by a vertical arrow.

With another arrow the general direction is indicated of the work progress of the crawler vehicle.

In figure 3b, the tube to be driven 11 is already introduced under pressure or percussion to the depth at which Columns 22 are ready. In this position the next work stage in which now through conduit 35 Dry binder is blown into the tube to be inflated, while Simultaneously, air can escape from the upper end.

Figure 3c shows the following stage of manufacturing a column shortly before its completion. Such as indicated by an arrow, the driven tube 11 has been extracted quite off the ground. With the flapper valve open at the lower end of the driven tube, due to the outflow of dry binder, another column 22 is almost finished

The devices are shown in figure 4 for the supply of the conduit 35. In detail a silo 41 for dry binder, from which through a propeller conveyor 42 with drive motor 43, se supplies binder to an outlet funnel 44 of a pump dosing 45. A dosing pump 45 is connected to a air compressor 46, which generates compressed air as a medium binder conveyor, which is then transported to the tube to be driven through the conduit 35.

Claims (10)

1. Procedure for soil improvement by providing a dry binder through a tube (11), previously driven into the ground, which has a tube cylindrical casing (12) and a flapper valve (17) located in the lower end of the casing tube, with the following sequence of stages: the casing tube is driven, with the valve closed hinge, vertically inside the ground until a predetermined depth, the dry binder is introduced inside of the driven tube, after filling the envelope tube with Dry binder to a partial height, the pipe driven while the flapper valve is open, continuing the binder contribution, thereby forming a column of dry binder, and said dry binder is introduced by insufflated into the envelope tube using compressed air as conveyor medium, characterized in that, during insufflation inwards, from the lower end of the casing tube, air simultaneously flows outwardly through an inner tube (13) that runs longitudinally therein. 2. Method according to claim 1, characterized in that the filling of the wrapping tube takes place at least half its height, before removing the tube. 3. Method according to any of claims 1 and 2, characterized in that the air is drawn out of the casing tube through the inner tube. Method according to any one of claims 1 to 3, characterized in that a modular grid is previously marked on the floor surface, in which each point of the grid determines the position of a column. 5. Method according to claim 4, characterized in that the lines of the grid are marked with a uniform separation from each other, between 15 and 100 cm from each other. Method according to any one of claims 1 to 5, characterized in that the columns are formed with a diameter of 100 to 200 mm. 7. Method according to any of claims 1 to 6, characterized in that lime or cement or mixtures of both are used as a dry binder. 8. Device for the improvement of the ground by means of the contribution of a binder, which comprises a pipe to be driven (11), constituted by a cylindrical casing tube (12) and a flap valve (17) arranged at the lower end of the casing tube , in which the casing tube is connected at its upper end with a device (15) for the transport of the dry binder, and for the transport of the dry binder by means of compressed air as a conveying means within the casing tube a compressed air generator is provided (45) or a fan, characterized in that an inner tube (13) that runs longitudinally inside the wrapping tube ends with its lower free end inside the wrapping tube and with its upper end comes out of the wrapping tube and goes to the environment. 9. Device according to claim 8, characterized in that at the upper end of the inner tube a vacuum cleaner is connected to aspirate air by removing it from the surrounding tube. Device according to any one of claims 8 or 9, characterized in that the tube to be driven is fixed to one of the driving jacks (33) of a tracked vehicle (32).