EP1234916A2 - Method for making column members - Google Patents

Abstract

Process for producing columns in ground having at least one unstable ground layer comprises shaking a displacement device (17) from the ground surface (11) through a non-supporting ground layer up to a supported ground layer (13, 14), constructing a lower column section (20) supported by the supported ground layer, inserting a tubular sleeve (22) from the ground surface into the lower column section, and filling the sleeve with material to form an upper column section supported by the sleeve. Independent claims are also included for a column body and an improved/stabilized building ground in which column bodies are distributed. Preferred Features: The material used to fill the upper column section is made from sand, water, concrete, stone, ballast, or gravel. The sleeve is made from a steel sheet, composite material or plastic.

Description

The invention relates to a method for producing columns in floors with at least one non-load-bearing floor layer for the purpose of soil improvement or stabilization. It Various processes are known, according to which they are not sufficient load-bearing surface by installing in one Grid arranged pillars is improved. Come here different mechanisms of action. For one, by deep column bodies transfer the load to lower ones load-bearing layers take place; besides, through that Installation of the pillar body without prior excavation of soil compaction between the column bodies; finally can when using dry binder in the column bodies Soil water can be extracted from cohesive soils.

Uncased are inexpensive for cost and procedural reasons Columns in the tamping or vibrating technique using deep vibrators with lock tube in one continuous operation can be built on a pedestal. This manufacturing technique reaches its limits or fails when Soft layers that do not have sufficient radial support forces can build up around the column body when loaded by loads to be able to keep its shape in the following non-supportable Soil layers called.

From DE 44 08 173 A1 and EP 0 900 883 A1 it is known Column body, which is in a stable floor layer reach in with a casing made of a pipe or a To provide geotextile material, initially excavation or a displacement of the soil occurs and then wrapping and Filling material can be introduced. With very deep, stable Layering is the process of temporary piping requires too expensive.

Proceeding from this, the invention is based on the object propose a method of making columns that for deep-seated viable or at least supportive Layers and non-supportable surface layers or Intermediate layers for time and cost advantages in the application leads. The solution to this lies in a process for Manufacture of pillars in floors with at least one non-load-bearing one Soil layer for the purpose of soil improvement or stabilization, with the following process steps to manufacture one of the columns, a displacement device, in particular a deep vibrator with a lock tube or a displacement tube with closure, is from the floor surface through the at least one non-load-bearing floor layer up to shaken a stable or at least supportable layer of soil, one directly from an at least sustainable soil layer supported lower column section, in particular by means of the displacement device, from bottom to top built up of rolled material, a tubular or tubular one Wrapping is from the bottom surface, at least one non-supportive soil layer penetrating down to the bottom Sufficiently installed column section, the covering becomes an upper supported by the envelope Column section filled with rolled material. This will compacted in the casing.

In low-priced further training, especially if load-bearing soil layers, initially becomes a thickened column base from rolled material, in particular by means of the displacement device, built into the load-bearing soil layer, on which the lower column section is then built.

The main advantage of the method is so far just possible with conventional tamping or vibrating technology manufactured to use uncased column bodies, which in particular on one in a viable or at least sustainable Layer of embedded thickened column base can rest, and the stability of the column body by using a cover only to a depth from which down sufficient continuous support to the bottom End of the column. The present Stratification is due to previous exploratory drilling or others Determine site exploration methods.

The columns of the invention are even when using only binder-free material, even with the expected Loads are dimensionally stable in that the wrapping in unstable floor area is designed so that it can be expected Stress states with possibly little radial deformation intercepts and thus the loads in the uncontaminated lower Column section and the column base entered without damage can be.

After a first procedure, the wrapping after first shaking and pulling the displacement device - After making the lower column section - on its lower end coaxially attached to this and at one second shaking of the displacement device to its intended Brought down depth. The process sequence poses This is initially the same as for the more common production Vibrating or stuffing columns, whereby, as already mentioned, when pulling the lower column section only up to a first Soft layer is prepared and the displacement device then pulled open leaving a displacement hole becomes. It may be necessary to add support fluid become. After that, the wrapping is on the displacement device attached and in a second additional shaking process pulled into the open vibratory opening and partly in the already existing lower column section brought in. Then the displacement device with immediate filling of the casing and compression of the Filling material (contractor procedure) are drawn or without Filling material is pulled, which is then from the top of the casing (from the bottom surface) can be.

After a second simplified procedure, the Wrapping at a distance from the lower end of the displacement device attached coaxially on this and already with a first shake of the displacement device - before making the lower one Column section - brought down with this and while pulling separated from this. The latter separation can take place automatically if there is effective driving means in only one direction be used. Special coupling agents, which are separable from the 'floor surface, be provided. This procedure involves the wrapping brought to the intended depth so that they up to reaches down into at least sustainable soil layers. At the Pulling the displacement device can pull the column material into introduced in a uniform process from bottom to top be, with the radial support in the upper area the wrapping already installed takes place. An accelerated Pull the displacement device in the area of the casing and filling material into the upper column section from the floor surface makes less sense, however not excluded.

The use of binder-free, rolling material - rock, Gravel, gravel, sand - in such cases in which the columns should also have a vertical drainage effect, i.e. if water permeability in the vertical direction should be guaranteed, or in which the same is not a disadvantage is.

In other cases, the use of binder rolling material - mortar, concrete - preferable, in particular if higher loads have to be removed and / or water exchange between different water-bearing layers is.

Essentially dimensionally stable tubular bodies come as a covering, be it without breakthroughs, be it with breakthroughs, from the known ones Materials such as sheet steel, composite material or Plastic into consideration. Another approach can be used as wrapping a geotextile hose, be it with a non-woven composite component or are used without a nonwoven portion. In this case there is a necessary radial state of stress in the column body only as a result of a significant radial expansion of the hose body. The pipe jackets used are usually designed as a tube open at the bottom. In the Use of geotextiles can be closed below Hoses for easier removal are cheaper his.

The present invention finds application wherever in the displacement or compaction of the soil when placing the necessary support tension of stuffing or vibrating columns or reaction stress in the upper soil layers - surface layers or intermediate layers - is not achieved and the floor is necessary for the functionality of the column radial support cannot build up or a horizontal one Run of the mortar or concrete when pouring cannot prevent it from hardening.

In the floor layers immediately above the lower end of the column, in which there is sufficient radial throughout Support is given, the pillar will be known accordingly Techniques made without additional wrapping.

In the area of load entry via the lower column section must be sufficiently viable or at least sustainable Layer are present, in which initially a column base made of rolling Material can be stuffed. Usually gravel, Crushed stone, sand, mortar or concrete, d. H. use case example Rolly material without or with added binding agent.

By using binder-containing material, a vertical flow can be reduced or prevented, so that a connection between different groundwater levels remains prevented.

In upper soil layers - surface layers or intermediate layers - in which there is sufficient radial support for the Column is not guaranteed, the column is according to the invention with a covering consisting of pipes or geotextile hoses manufactured.

The upper column section (with cover) can be independent of the design of the lower column section (without cover) with rolled material with or without added binding agents filled and stuffed, usually with gravel, crushed stone, Sand, mortar or concrete.

If an envelope is used made of a material that is used for Load application experiences a significant stretch, so in particular with a geotextile covering, it is advantageous the filling material in the cover immediately during column manufacture condense so that no significant additional Strains occur when the load is applied and are only compatible with the building Settlements have to be accepted later.

In soil layers in which for uncased columns, e.g. B. Ballast columns, mortar-filled darning columns, ready-made mortar darning columns, Concrete vibrating columns, not required supporting tensions permanent through displacement and compaction of the surrounding soil can be generated, d. H. in which the floor is only in To a small extent contributes to the radial support tension, this must therefore to a large extent by the circumferential expansion of the Wrapping applied when introducing the filler material.

The wrapper can also be used for an exchange or chemical reactions of the column material with the soil, the soil moisture to prevent the groundwater, for example a change in the pH value in the surrounding soil to reduce the incorporation of binders or entirely avoid.

With the method according to the invention, stable columns can be are produced immediately or after hardening of the if necessary used binder can be loaded. by virtue of their method of manufacture is only small settlements expected to be applied.

Figur 1

zeigt ein erstes, zweistufiges erfindungsgemäßes Verfahren zur Herstellung von Säulen unter Verwendung einer Rohrumhüllung;

Figur 2

zeigt ein zweites, zweistufiges erfindungsgemäßes verfahren unter Verwendung einer Geotextilumhüllung;

Figur 3

zeigt ein drittes, einstufiges erfindungsgemäßes Verfahren unter Verwendung einer Rohrumhüllung;

Figur 4

zeigt ein viertes, einstufiges erfindungsgemäßes Verfahrend unter Verwendung einer Geotextilumhüllung.

Before the subsoil to be improved is produced, a detailed excavation of the subsoil is required; In particular to determine the required length of the coverings, pressure probes are preferably carried out in a narrow grid, with which the transition from non-supportable floor layers to supportable or load-bearing floor layers is determined. The lower boundary layer of the lowest unsustainable bottom layer determines the depth of the cladding, the support and load-bearing bottom layers essentially do not need to be distinguished. The method can be used without further ado if there are only well-bearing soil layers under the non-supportable soil layers. However, it is also analogously applicable if under the non-supportable floor layers there are only at least supportable floor layers and the pillars in this area are sufficiently deep to cause load transfer primarily via skin friction.

Figure 1

shows a first, two-stage method according to the invention for the production of columns using a tubular casing;

Figure 2

shows a second, two-stage method according to the invention using a geotextile covering;

Figure 3

shows a third, one-step method according to the invention using a pipe jacket;

Figure 4

shows a fourth, one-step method according to the invention using a geotextile covering.

In Figure 1, the production of a in four phases a) to d) shown column according to the invention. A vertically cut Soil with the surface 11 has a non-load-bearing and non-supportable top layer 12 (soft layer), below an at least supportable bottom layer 13 and finally underneath a well-bearing floor layer 14.

In illustration a), one is in position on surface 11 brought caterpillar 15 shown in its erected Leader 16 a vibrator 17 is guided, which is a feed hopper 18 passes through for material introduction. The jogger tip is vibrated into the load-bearing floor layer 14. With dashed lines is a thickened column base 19 shown, the optional in a first step Vibratory compaction or stuffing compaction from rolling material - with or without binder surcharge - can be generated.

In the illustration b), the vibrator 17 is already complete pulled, whereby - on the optional column base 19 - a lower column section using vibrating or tamping technology 20 is built from rolly material that extends into the load-bearing Bottom layer 14 extends radially directly from the bottom the supportable bottom layer 13 is supported. This lower one Column section 20 extends into the unsustainable top Bottom layer 12 slightly into it, while the rest Displacement hole 21 can be seen in this bottom layer. On the lower end of the vibrator 17, a tube 22 is coaxial which has inner drivers 24 at the lower end, that of driver pin 23 at the lower end of the vibrator can be taken.

In illustration c) it is shown that the vibrator 17 and with it the sheathing tube 22 in a second vibrating process up to the upper end of the lower column section 20, i. H. in particular reaching into the at least supportable bottom layer 13 are introduced. The lower column section 20 has received an upper thickening 25.

The illustration d) shows that the final Pulling the vibrator 17 the sheathing tube 22 over the vibrator has been filled with rolling material that is in suitable Dimensions can be compressed, creating an upper column section 26 arose with radial support through the sheathing tube 22 is. Instead of the cladding tube open here used below 22 could also be closed at the bottom by a cover Pipe set in the lower column section 20 become.

In Figure 2, the same details as in Figure 1 are the same Provide reference numbers, the process sequence of column manufacture largely similar to that in Figure 1 in individual steps shown. The description there is so far Referred.

However, according to illustration b), one below does not deviate open cladding tube, but a closed bottom Hose 27 made of geotextile during the second vibrating process from Vibrator 17 drawn into the vibrating hole 21.

The result of this vibrating process is shown in illustration c) recognizable, here also the envelope 27 in the lower Column section 20 has penetrated and a widening 25 on the head.

As shown in illustration d), the geotextile hose 27 to form an upper column section 28 with rolled material filled, the hose 27 by radial expansion Support forces can build up and the filling material essentially demarcated from the ground.

3 shows essentially the same device situation in three phases and the same soil stratification as in the figures 1 and 2 shown. The same details are the same Provide reference numbers. The description there is so far Referred. Here, however, a solid sheathing tube is used 22 'during the first vibrating process of the vibrator 17 according to illustration a) at a distance from the vibrator tip pushed coaxially onto the vibrator and brought down into the ground. The corresponding driver means 23, 24 are located at a corresponding distance from the vibrator tip. Here, too, there is a thickened column base with dashed lines 19, the optional in the load-bearing soil layer 14 can be constructed. The cladding tube 22 'already has reaches its intended position that the non-supportive Soil layer 12 penetrates and into the at least Sustainable bottom layer 13 protrudes.

In illustration b), the vibrator 17 is already inside of the cladding tube 22 'withdrawn after being pulled a lower column section 20 in the area of at least Sustainable bottom layer 13 has generated the radially immediately is supported by the ground.

In the illustration c), the vibrator 17 is completely out of the Wrapping tube 22 'pulled up, the wrap tube 22 'to form an upper column section 28 is filled with rolly material that differs from the material here of the lower column section 20 differs.

In Figure 4 is essentially the same terrain and equipment situation and the same sequence of processes as in FIG. 3 shown. The same details are given the same reference numbers Mistake. In this respect, reference is made to the description of FIG. 3 taken. Instead of a rigid cladding tube is here a less recognizable geotextile tube open at the bottom 27 'pulled over the middle section of the vibrator 17 and so far taken down that he was the unsustainable bottom layer 12 penetrates and with the lower end in the least Sustainable bottom layer 13 protrudes. The pillar foot 19 is already finished in the area of the load-bearing floor layer 14 posed.

According to the representation b) when pulling the vibrator 17 here made of the same material as the column base 19 lower Column section 20 which is directly in the lower bottom layer 13 is supported radially.

According to the representation c) after the complete pulling of the Vibrator 17 a based on the lower column section 20 upper column section 28 by filling the geotextile hose 27 'with the same material. The radial Supporting forces for the filling material are the result a radial expansion of the wrapping tube 27 '.

The common principle can be seen in the illustrations to reduce costs and reduce material consumption additional covering for the column material only in the area not at least supportable upper soil layers. This reduces the need for support bodies by length as well as the consumption of filling material in the area of non-supportive layers. The load is transferred via the entire column body into the lower layers of the floor, load transfer in the area of the lower column section via jacket friction in addition to the bearing load of the column base or as an exclusive force transmission into the ground becomes possible.

LIST OF REFERENCE NUMBERS

11

ground surface

12

non-supportive soil layer

13

at least sustainable soil layer

14

load-bearing soil layer

15

vehicle

16

broker

17

Jogger

18

funnel

19

pedestal

20

lower column section

21

Rüttelloch

21

cladding tube

23

Driver (17)

24

Driver (22)

25

thickening

26

upper column section

27

Geotextilumhüllung

Claims (17)

Method for producing pillars in soils with at least one non-load-bearing soil layer for the purpose of soil improvement or
stabilization, with the following process steps for producing one of the columns,
a displacement device (17), in particular a deep vibrator with lock tube or a displacement tube with closure, is shaken from the floor surface (11) through the at least one non-load-bearing floor layer into a load-bearing or at least supportable floor layer (13, 14),
a lower column section (20) is supported directly by an at least supportable bottom layer (13, 14), in particular by means of the displacement device (17), from bottom to top of rolled material,
a tubular or tubular casing (22, 27) is inserted from the bottom surface (11), penetrating at least one non-supportable bottom layer (12), into the lower column section (20), the casing (22, 27) to form an upper pillar section (26, 28) supported by the covering, filled with rolled material. Method according to claim 1,
characterized in that first a thickened column base (19) made of rolled material, in particular by means of the displacement device (17), is installed in the load-bearing or at least supportable bottom layer (13, 14), on which the lower column section (20) is then built. Method according to one of claims 1 or 2,
characterized in that the sheath (22, 27) after a first shaking and pulling of the displacement device (17) - after the manufacture of the lower column section - is coaxially fastened to the lower end thereof and upon a second shaking of the displacement device (17) is brought down to its intended depth. Method according to one of claims 1 or 2,
characterized in that the sheathing (22, 27) is fastened coaxially to the lower end of the displacement device (17) and when the displacement device (17) is shaken for the first time - prior to the manufacture of the lower column section - it is brought down and pulls out separates from it or is separated from it. Method according to one of claims 1 to 4,
characterized in that binder-free, rolling material - rock, gravel, gravel, sand - is used. Method according to one of claims 1 to 4,
characterized in that binder-containing, rolling material - mortar, concrete - is used. Method according to one of claims 1 to 6,
characterized in that a tubular body (22) as the covering - without openings, with openings; from sheet steel, from composite material, from plastic - is used. Method according to one of claims 1 to 7,
characterized in that a geotextile tube (27) - with non-woven composite portion - is used as the covering; without fleece content - is used. Method according to one of claims 7 or 8,
characterized in that an envelope (22, 27) closed at the bottom is used. Column body in the soil to improve or stabilize soils with at least one non-load-bearing soil layer, comprising
an uncased lower column section (20) which is built into load-bearing or at least radially supportable floor layers (13, 14),
an upper column section (26, 28) provided with a covering (22, 27) which penetrates at least one non-supportable bottom layer (12) and extends with its covering (22, 27) into the lower column section (20). Column body according to claim 10,
marked by
a column base (19) embedded in a load-bearing or at least supportable floor layer (13, 14), on which the lower column section (20) is built. Column body according to one of claims 10 or 11,
characterized in that binder-containing, rolling material - mortar, concrete - is used. Column body according to one of claims 10 or 11,
characterized in that binder-containing, rolling material - mortar, concrete - is used. Column body according to one of claims 10 to 13,
characterized in that a tubular body (22) as the covering - without openings, with openings; from sheet steel, from composite material, from plastic - is used. Column body according to one of claims 10 to 13,
characterized in that a geotextile tube (27) - with a fleece filling, without a fleece portion - is used as the covering. Column body according to one of claims 10 to 15,
characterized in that an envelope (22, 27) closed at the bottom is used. Improved or stabilized subsoil, in which pillar body according to one of claims 10 to 16 according to one Surface grids are installed distributed.

Images