AT519819A2 - PROCESS FOR FOLLOWING GROUND FASTENING - Google Patents

Abstract

The invention relates to a method for subsequent soil consolidation in congested structures to support the structures against the ground. In order to keep horizontal lateral forces away from the bridge structure, it is provided according to the invention that, in addition to the existing walls, a heavyweight wall is created which can intercept the horizontal forces, the method comprising the steps of: - pressing several pipes (2) into the ground behind the structures Arranging the tubes (2) in at least two rows (5), wherein the tubes (2) of a row are arranged approximately parallel to the building and have the smallest possible distance from each other, - arrangement of the tubes (2) in at least one second row (5 ) with an offset of approximately 50% to the adjacent row, - Pressing the soil within the tubes (2) with a cement.

Description

Summary

The invention relates to a method for subsequent ground stabilization in overloaded structures in order to support the structures against the ground. In order to keep horizontal transverse forces away from the bridge structure, the invention provides that, in addition to the existing walls, a heavy weight wall is created which can absorb the horizontal forces, the method comprising the following steps:

- Pressing several pipes (2) into the soil behind the structures

Arrangement of the tubes (2) in at least two rows (5), the tubes (2) of one row being arranged approximately parallel to the structure and being as close as possible to one another,

- arrangement of the tubes (2) in at least one second row (5) with an offset of approximately 50% to the adjacent row,

- Pressing the soil inside the pipes (2) with a cement.

Figure 1/16

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Subsequent soil consolidation procedures

The invention relates to a method for subsequent ground stabilization in overloaded structures in order to support the structures against the ground.

Many bridges in Germany were built in the 1970s to bridge rivers and bodies of water. In addition, there are many bridges that have been built with large spans over carriageway or railway lines. The static requirements in the 1970s were generally complied with, but these no longer correspond to today's standards, especially not the Euro 2 standard, so that when the bridge structures are renovated, static checks usually also take place and appropriate measures to stabilize the bridge structures must be initiated. This affects several hundred bridges in NRW alone, the construction of which is not possible due to time and cost reasons to meet today's requirements. Rather, there is a need to carry out renovation measures on the bridge structures and to increase the static loads accordingly. Work on the existing bridges should, if possible, not or only partially lead to the closure in order to maintain the flowing traffic.

The present invention is therefore based on the object of demonstrating a novel method with which the static requirements of existing structures, in particular of angular support walls in bridge structures, can be increased.

According to the invention, a new method for subsequent soil stabilization is shown for the solution, which comprises the following individual steps:

- pressing several pipes (2) into the soil behind the structures, / 16

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Arrangement of the tubes (2) in at least two rows (5), the tubes (2) of one row being arranged approximately parallel to the structure and being as close as possible to one another,

- arrangement of the tubes (2) in at least one second row (5) with an offset of approximately 50% to the adjacent row,

- Pressing the soil inside the pipes (2) with a cement.

Further advantageous embodiments of the invention result from the subclaims.

The method according to the invention is intended for subsequent ground consolidation in the case of overloaded structures. This can be bridge structures, a listed wall or a water structure. In particular, the walls of historical buildings that need support are suitable as walls. For subsequent soil stabilization, several pipes are pressed into the soil behind the buildings, the pipes being arranged in at least two rows and the pipes of one row being arranged approximately parallel to the building and being as far apart as possible. The pipes are arranged in at least one second row with an offset of approximately 50% to the adjacent row. This is followed by pressing the soil inside the pipes with a flowable cement. The cement or cement mixture bonds with the existing soil as far as possible, namely with an existing sand or gravel soil.

The method according to the invention is particularly suitable for subsequent ground consolidation in the case of overloaded bridge structures with angled retaining walls. The existing bridge structures with angled retaining walls are essentially overloaded due to horizontal forces that arise due to earth pressure and vehicle traffic. Due to the increasing traffic on the roads by trucks with a high transport weight, the existing access roads put considerable pressure on the vehicle being driven / 16

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Soil and thus exerted on the angled retaining walls, which can lead to a horizontal overload of the bridge structures. It is therefore necessary to take the horizontal pressure at least partially from the bridge structure or the angled retaining walls by means of appropriate security measures. For this reason, it is provided that a heavyweight wall is built behind the angle support walls, which protects the angle support walls and thus the entire bridge structure from the horizontal forces. The horizontal forces are almost completely absorbed by the heavyweight wall and discharged into the ground. For this purpose, several pipes are pressed into the soil behind the angle support walls, the pipes being arranged in at least two rows and running in one row approximately parallel to the angle support wall. In this case, the individual tubes should have the smallest possible distance from one another. A second row of tubes provides an offset of approximately 50% of the tube diameter, so that a stable heavy weight wall can be created due to the achievable higher packing density of the individual tubes. The pressed pipes are pressed with a cement, so that the materials present in the ground, for example a gravel or sand filling, form an extremely stable connection within the ground with the cement. It is also possible to press the cement into the ground below the pipes.

Depending on the size of the bridge structure, several rows of pipes can be arranged next to one another, for example 2 to 6 rows, which are each offset from one another in order to absorb the horizontal forces. The heavyweight wall ensures that the horizontal forces do not press against the angled retaining walls, walls or hydraulic structures, but are absorbed by the heavyweight wall and discharged into the ground. By staggering the rows to each other, a continuous heavyweight wall can be created, the narrow grid of the pipes after filling with cement acting like concrete reinforcement and safely absorbing the horizontal forces. After the completion of such heavyweight walls, it was determined by analyzes that the / 16

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Compressive strength is up to 25.6 N / mm ² and thus the occurring horizontal forces can be adequately absorbed.

With this method, a major advantage of bridge structures is that the bridge access only has to be blocked on one side in the area of the construction site, because only one half of the road is required to carry out the work. The traffic can thus be led over the other area of the road, and after the one-sided heavyweight wall has been completed, the further section of the roadway width can be consolidated in a similar manner by changing the traffic routing. Extensive earthworks are not necessary because the necessary pipes are pressed directly into the soil behind the corner support walls.

Depending on the size of the building, it is provided that the pipes are arranged in 2 to 6 rows, preferably in 3 to 4 rows next to one another, each row being offset by approximately 50% to the adjacent row.

In a further embodiment of the invention it is provided that the pipes are pressed in at least to the bottom point of a bridge structure, a listed wall or hydraulic structures. In individual cases, however, the pipes can be pressed in much deeper than up to the base point, with the upper edge of the pipes reaching to the crown of the angular support wall or just below it in a further embodiment of bridge structures. Correspondingly to the earth level or just below it with a listed wall or a water structure. In the case of a bridge structure, the rows formed from the tubes extend over the entire width of the angular support wall and are preferably produced in two work steps which, depending on the width of the roadway, lead to a diversion of traffic, but do not entail any further impairments. In particular, no elaborate work is required, since the existing soil is sufficient for pressing in the pipes and for pressing. In the case of a listed wall or a water structure, the pipes can be used in an endangered section.

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4 to 5 tubes with a required diameter of approximately 20 to 250 mm diameter are used per square meter per meter due to the adjacent tubes and the intended packing density. The rows in which the pipes are arranged usually start just behind the angled retaining wall, a wall or a water structure and are arranged in the direction of the soil behind the angled retaining wall or wall.

The angled retaining wall of a bridge structure here has a foot element which is T-shaped, the T-shaped end being embedded in the floor and only the vertically ascending angled retaining wall protruding upwards. Insofar as the tubes are pressed in directly next to the angled support wall, the individual tubes sit directly on the foot element of the angled support wall, whereas, in contrast, the removed rows can be pressed in deeper next to the foot element.

In order to obtain a higher stability of the pipes, in special cases, in particular when supporting hydraulic structures or historical walls, it is provided that the soil is removed from the pipes and the pipes are filled with a cement or cement mixture.

A micro-cement with a fineness of 3500-20,000 Blaine (cm ² per gram) is preferably used to inject the soil inside the pipes. The fineness of the cement or cement mixture ensures that the cement substances or the filling material pressed in by the injection plants can penetrate deep into the ground below the pipes and thus form a firm connection.

In a further embodiment of the method, it is provided that a sufficient amount of moisture is added to the pressed-in substance, or that the substance is enriched with a sufficient amount of moisture, or that the pressed-in substance

36910 pressed substance at least partially reacts with the moisture of the filling material from the fill behind the angled support wall and hardens.

The cement substance can in this case be pressed in a plurality of work steps carried out one after the other, wherein an at least partial hardening can be awaited between the work processes. This makes it possible to carry out a tight compression up to the upper edge of the pipes, starting from the lower pipe ends.

For a further preferred embodiment of the method, it is provided that the substance is supplied to the soil or filler material by an injection lance, the depth of which can be adjusted.

In a further particular embodiment of the invention, it is provided that quality assurance measures are used to carry out an ongoing or subsequent check of the substance injection that has taken place. For this purpose, for example, a georadar can be used, which is used for an analysis of the soil area during or after the completion of the injection process and thus enables control over the existing penetration depth and spread of the substance in the soil or filler material. Alternatively, for quality assurance there is the option of using a seismic method, which also enables the compression to be checked.

Overall, the present method has the advantages that a subsequent retaining wall can be created without large earthworks, which can absorb the horizontal forces. In this way, the pressure can be taken from the bridge structure, in particular the angular support walls, based on the soil and the loads caused by traffic. As a result, the Eurocode 2 standard is met and the bridge structures do not have to be completely rebuilt. It is possible to arrange several pipes next to each other in a row and several next to each other / 16

36910 arranged rows build a sufficient heavy weight wall, which has a sufficient stability due to an offset of the individual pipes to the adjacent rows and can absorb the transverse forces that occur.

The invention is explained in more detail below with reference to the figures.

It shows

Fig. 1 in a sectional side view of an angle support wall with pressed-in steel tubes in several rows and

Fig. 2 in a sectional plan view of the angle support wall with the arrangement of the pressed tubes.

Figure 1 shows a sectional side view, for example, an angle support wall 1 and pressed tubes 2 in several rows 5. The angle support wall 1 belongs to a bridge structure and is located at the end of the bridge structure in front of the ground of the bank area. The angled support wall 1 consists of a foot element 3 and a vertical support element 4, which are poured from concrete at the time of the bridge construction, in order to subsequently fill up the earth, the earth being on the side facing away from the bridge construction. Pipes 2 are pressed into the ground behind the angled support wall 1 in accordance with the present method for subsequent ground fastening in the case of overloaded bridge structures with angled support walls 1. A plurality of rows 5 of tubes 2 lying next to one another are preferably used here, which, in addition, as can be seen particularly in FIG. After being pressed in, the pipes 2 are pressed with cement, the existing filling usually being pressed behind the angled support wall 1 with the cement or the cement mixture. The pipes 2 or row 5 of the first pipes 2 arranged directly behind the angled support wall 1 are seated on the foot element 3, while other adjacent rows 5 are pressed deeper into the ground / 16

36910 can be, preferably up to below the sole of the foot element and possibly beyond.

Figure 2 shows a sectional plan view along the section line A-A on the angle support wall 1 with foot element 3 and the tubes 2, which are arranged in four adjacent rows 5. The individual tubes 2 of a row 5 are closely adjacent and already form an almost closed wall, the tubes 2 of two further adjacent rows 5 being arranged offset to one another. This means that the pipes are offset by approximately 50% from the adjacent row. Depending on the size of the bridge structure, the diameter of the pipes 2 and the number of rows 5 can be determined, it essentially depends on which horizontal forces can arise, for example due to vehicle traffic or due to the geographic conditions and arrangement of the bridge structure.

With the help of the tubes 2, which are arranged side by side in several rows 5, a heavy weight wall is built up, which ensures that transverse forces that press against the angular support walls 1 from the direction of the earth can be largely absorbed and guided into the ground, whereby the angled support wall 1 has to absorb significantly less lateral forces.

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LIST OF REFERENCE NUMBERS

Angular retaining wall

Tube

foot element

support element

Rows / 16th

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Claims (17)

claims 1. Method for subsequent soil consolidation in the case of overloaded structures in order to support the structures against the ground, characterized by - pressing several pipes (2) into the soil behind the structures, Arrangement of the tubes (2) in at least two rows (5), the tubes (2) of one row being arranged approximately parallel to the structure and being as close as possible to one another, - arrangement of the tubes (2) in at least one second row (5) with an offset of approximately 50% to the adjacent row, - Pressing the soil inside the pipes (2) with a cement. 2. The method according to claim 1, characterized in that the tubes (2) in 2 to 6 rows (5), preferably in 3 to 4 rows (5) are arranged side by side. 3. The method according to claim 1 or 2, characterized in that each row (5) is arranged offset by approximately 50% to the adjacent row (5). 11/16 36910 4. The method according to claim 1-2, characterized in that the pipes (2) are pressed into the soil behind an angled retaining wall of a bridge structure, or that the pipes (2) are pressed into the ground by listed walls or hydraulic structures. 5. The method according to claim 4, characterized in that the tubes (2) are pressed in at least up to the bottom point of a bridge structure, a wall or a water structure. 6. The method according to claim 4 or 5, characterized in that the upper edge of the tubes (2) extend to the crown of the angled support wall (1) or to the earth level of a wall or a hydraulic structure. 7. The method according to any one of claims 4 to 6, characterized in that 12/16 36910 that the rows (5) are formed over the entire width of the angular support wall (1) or a wall or a hydraulic structure. 8. The method according to any one of claims 1 to 7, characterized in that the tubes (2) arranged directly on the angle support wall (1) are seated on the foot element (3) of the angle support wall (1). 9. The method according to any one of claims 1 to 8, characterized in that 4 to 5 pipes (2) are provided per square meter. 10. The method according to any one of claims 1 to 9, characterized in that the soil is removed from the pipes (2). 11. The method according to any one of claims 1 to 10, characterized in that the tubes (2) are filled with a cement or cement mixture. 13/16 36910 12. The method according to any one of claims 1 to 11, characterized in that a micro-cement is used as the cement. 13. The method according to one or more of claims 1 to 12, characterized in that the injected substance moisture is supplied in a sufficient amount or that the substance is enriched with a sufficient amount of moisture or that the injected substance with the moisture present in the soil or filler material at least partially reacts and hardens. 14. The method according to one or more of claims 1 to 13, characterized in that a cement or cement mixture having a fineness of 3,500 to 20,000 Blaine (cm ² / g) is used as the substance. 15. The method according to one or more of claims 1 to 14, characterized in 14/16 36910 that the substance is fed into the soil or filling material through an injection lance, which can be adjusted in depth. 16. The method according to one or more of claims 1 to 15, characterized in that an ongoing and / or subsequent control of the substance pressing is carried out by quality assurance measures. 17. The method according to one or more of claims 1 to 16, characterized in that, for example, a georadar is used to carry out the quality assurance measures, is used during the injection method for analyzing the floor area. 15/16 36910

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