JPH08170334A - Preparation of banking - Google Patents

Abstract

PURPOSE: To inhibit secondary consolidation generated after the completion of the preparation of a banking effectively, and to suppress the increase of cost. CONSTITUTION: A process, in which a banking scattered layer 411 is spread and compacted and a drainage-material filling section 412 is formed onto the layer 411, is repeated at a plurality of times, thus forming a banking layer molded form 41A. A required number of buried posts 421 are driven to the banking layer molded form 41A while buried bearing plates 422 are laid extending over the upper ends of the posts 421 and the top face of the banking layer molded form 41A, thus constructing a banking bearing structure 42A. A banking layer molded form 41B is formed onto the structure 42A in the same manner as the banking layer molded form 41A. A banking 4 consisting of banking layer molded forms 41A, 41B, 41C at a required number of stages and banking bearing structures 42A, 42B is banked and constructed by such processes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, for example, in the formation of an embankment using a soft cohesive soil such as Kanto Loam, terminates the short-term subsidence of the embankment in the formation process early and
The present invention relates to a method for suppressing the deformation of the embankment due to long-term subsidence after completion of the preparation.

[0002]

2. Description of the Related Art Conventionally, as a method of constructing a high embankment using a soft cohesive soil such as Kanto loam, a consolidation promotion method using a drainage material and an improvement treatment method for a soft cohesive soil are known. Among them, the former method of promoting consolidation is to form a drainage layer of chemical products or crushed stones at appropriate intervals between the embankment layers by sprinkling and compacting the above-mentioned cohesive soil, and promoting drainage from the embankment layer. It saves time. The latter improved treatment method is one in which a clay-based or cement-based stabilizing treatment material is mixed, or the clay soil material is improved by drying or heat treatment in advance, and then this clay soil material is used as the embankment material. is there.

[0003]

Among the above-mentioned conventional methods,
For example, according to the consolidation promotion method using drainage material, it is possible to promote primary consolidation by draining excess pore water containing soft cohesive soil as embankment material, but long-term settlement (secondary consolidation ) Can not be suppressed to effectively prevent the deformation of the embankment. Therefore, it is necessary to make an extra embankment of a predetermined height on the embankment in anticipation of deformation due to secondary consolidation, and if other structures are constructed on this embankment, this structure will be destroyed by long-term settlement as described above. It is inevitable to be affected. Further, according to the method for treating soft cohesive soil, the amount of embankment material that must be improved in a large-scale high embankment work is enormous, so the cost associated with the improvement becomes enormous.

The present invention has been made under the above circumstances, and its technical problem is to effectively suppress the secondary consolidation that occurs after the completion of the embankment and suppress the increase in cost. The purpose is to provide a method of creating an embankment that can be used.

[0005]

The above-mentioned technical problems are as follows.
The present invention can effectively solve the problem. That is, the method of forming the embankment according to the present invention, the embankment layered body of a predetermined thickness with a drainage material filling portion interposed between these embankment spreading layers while compacting by sequentially sprinkling a plurality of embankment spreading layers,
A structure in which a required number of embedded pillars penetrating vertically through this embankment stratification are driven and a required number of steps are built up with the embankment support structure in which an embedding support plate is laid over the upper end of the embedding pillar and the upper surface of the embankment stratification. Is. In this case, the embedded support plate is typically a metal net or a metal perforated plate, or a large number of beam-shaped steel plates are laid so as to intersect in a grid pattern.

[0006]

According to the above-mentioned construction method, first, in forming the embankment layer body, excess porosity in the embankment material of each embankment layer is gradually spread during the process of spreading and embedding the embankment layer in order. Since the water is satisfactorily drained through the drainage material filling portion interposed between the outlet layers and the like, required primary consolidation is performed in parallel.
The embankment support structure consisting of the embedded support pillars driven into the embankment after consolidation and the upper end of the embankment support and the embedded support plate laid over the upper surface of the embankment, supports the weight of the embankment to be re-embedded on it. Therefore, the secondary consolidation phenomenon, which is the long-term creep deformation of the embankment stratum on the lower layer side, is suppressed, and the long-term settlement deformation is effectively prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a method for forming embankment according to the present invention will be described with reference to the drawings. First, FIG. 1 is a sectional view showing a completed state of embankment having a predetermined height. That is, in FIG. 1, reference numeral 1 is the ground, 2 is a drainage layer formed by laying a drainage material such as crushed stone on the ground 1, and 3 is an outer side made of good quality earth material forming a slope 3a. Embankment 4 is an inner embankment that is erected behind this outer embankment 3, and this inner embankment 4 is an embankment stratified body 41A to 41C that is built up in three stages and the first stage from the bottom. And the embankment support structures 42A and 42B provided on the embankment layered bodies 41A and 41B of the second stage.

Each embankment layered body 41A, 41B, 41C is
A large number of embankment spreading layers 4 each of which is embossed with cohesive soil such as Kanto loam and compacted in a predetermined layer thickness.
11 and a drainage material filling portion 412 formed between each of the embankment spreading layers 411 and 411. Each drainage material filling section 412 lays a drainage material such as a chemical drainage material or crushed stone composed of large granules in a hollow area on the upper surface of the embankment spouting layer 411, and further sprinkles the embankment ejection layer 411 on it. It is formed in an interposing state between the embankment spreading layers 411, 411 by compacting and compacting, and is laid in, for example, a horizontal grid or stripe pattern, or the embankment spreading layer 411.
Is layered over the entire surface of. Further, preferably, these drainage material filling portions 412 are continuous with each other through a vertical drainage material filling portion (not shown) formed in a substantially vertical direction, and are also continuous with the bottommost drainage layer 2 of the embankment 4. ing.

Each embankment support structure 42A, 42B has a large number of embedded struts 421 driven into the embankment stratification 41A or 41B, its upper end and the embankment stratification 4 respectively.
It is composed of a buried support plate 422 laid over the upper surface of 1A or 41B. The embedded support columns 421 are typically made of steel sheet pile, for example, and the embedded support plates 422 are shown in FIG.
As shown in the plan view of FIG. 3, a steel net or a perforated steel plate is laid in a state of being installed on the embedded support columns 421, or as shown in the plan view of FIG.
a and 422b are installed between the embedded columns 421 and laid in a state of intersecting in a grid pattern. As a result, water permeability (drainability) from the second-stage embankment stratified body 41B or the third-stage embankment stratified body 41C that is piled up on the embedded support plate 422 is secured. The embedded support columns 421 are not limited to the ends of the embedded support plate 422, but are also required in the plane direction thereof, for example, beam-shaped steel plates 422a and 422b in FIG.
Properly arranging it also at the intersections of the above is effective in suppressing the flexural deformation of the embedded support plate 422 due to the weight of the embankment stratified bodies 42B and 42C piled up on it, and improving the strength thereof.

According to the construction method of this embodiment, for example, in the formation of the first-stage embankment layer structure 41A, the embankment sprinkling layer 411 is sprinkled out and compacted, and the drainage material (drainage material filling portion 412) is formed thereon. Is laid, and the embankment spreading layer 411 is further laid on it.
In the process of repeating the operation of sprinkling out and compacting the soil, the excess pore water contained in each embankment spouting layer 411 is discharged from the drainage material filling section 412 to the outer embankment 3 and the drainage layer 2 of good quality soil material. Water is drained satisfactorily through the drainage material filling portion 412 through the vertical drainage material filling portion and the drainage layer 2 which are not shown. For this reason,
The embankment layer 41A is piled up and its primary consolidation is performed. In the process of forming the embankment stratified body 41A by this process, the primary consolidation situation at every place of the embankment stratified body 41A is detailed by constantly measuring the amount of drainage from the drainage layer 2 and the subsidence amount of the embankment upper surface due to this drainage. To understand.

When the formation of the embankment stratified body 41A has been completed, drainage and subsidence have been completed, and it has been confirmed that the required primary consolidation has been substantially achieved, as shown in FIG. 4, self-propelled pile driving. The embedded columns 421 are driven into the embankment stratified body 41A at a predetermined interval by the machine 4 or the like. This buried support 42
1 is penetrated through the embankment stratified body 41A so that the lower end reaches the ground 1 and the upper end is substantially flush with the upper surface of the embankment stratified body 41A. When the driving of the embedded support columns 421 is completed, the embedded support plate 422 is laid on the upper surface of the embankment stratified body 41A as shown in FIG. 2 or 3.
The construction of the first embankment support structure 42A is completed. The embedded support column 421 and the embedded support plate 422 are fixed to each other by a suitable joining means such as bolts and nuts or welding.

After the construction of the first-stage embankment support structure 42A is completed, the embedded support plate 422 of the embankment support structure 42A is completed.
The second-stage embankment stratified body 41B is piled up by the same process as the above-mentioned formation of the first-stage embankment stratified body 41A. Then, when it is confirmed that the required primary consolidation of the embankment layered body 41B is substantially achieved, the embedding support columns 421 are driven again and the embedding support plate 422 is laid, whereby the embankment support structure 42B of the second stage is laid. To build. In this case, the embedded support columns 421 are driven so as to abut against the upper surface of the first-stage embankment support structure 42A.

By the steps as described above, the embankment 4 is prepared by embedding the required number of embankment layered bodies. The embankment layered body 41C at the uppermost stage (third stage in the illustrated embodiment) is embanked. It is not necessary to build the support structure. This is because the first-step embankment support structure 42A has the second- and third-step embankment stratified bodies 41B and 41C that are set up on the embankment support structure 42A.
By supporting the weight of the
The secondary consolidation phenomenon, which is a long-term creep deformation of 1A, is prevented, and the second-stage embankment support structure 42B has the weight of the third-stage embankment stratified body 41C piled up thereon. By supporting, the secondary consolidation phenomenon of the second-stage embankment stratified body 41B is prevented, but there is no further upper-stage embankment stratified body to be supported on the uppermost-stage embankment stratified body 41C. However, when a heavy construction or the like is constructed on the constructed embankment 4, it is effective to provide the embankment support structure to the uppermost embankment layered body 41C as necessary.

According to the construction method of this embodiment, since a multi-tiered frame structure is constructed by the embankment support structures 42A and 42B in the embankment 4 that has been primarily consolidated, the embankment 4 is reinforced and the embankment stratified body is formed. Since the secondary consolidation of the embankment layered body 41A or 41B in the lower stage due to the weight of 41B or 41C is suppressed, long-term subsidence deformation of the embankment 4 is effectively prevented. Therefore, even when the embankment material used for the embankment spreading layer 411 is a soft cohesive soil, it is not necessary to improve the embankment material with a stabilizing treatment material, and a large amount of stabilizing treatment material or No time is needed. The surplus pore water generated in the embankment 4 due to the rainfall during construction is the drainage material filling portion 412 between each embankment spouting layer 411, the perforated plate of the embankment support structures 42A and 42B, or the grid-like embedded support plate. Four
The water is satisfactorily drained to the outside through the gap 22 and the drainage layer 2.

In the illustrated embodiment, the embankment layered bodies 41A to 41C having three upper and lower layers are described, but the present invention is not limited to this, that is, four layers. The above can be applied. Also,
As the embedded support columns 421, steel piles, steel piles such as steel frames, and various piles can be used.

[0016]

According to the embankment forming method of the present invention,
The following effects are realized. (1) Since primary consolidation is performed during the process of forming the embankment and the embankment support structure is embedded in multiple stages, it is possible to effectively prevent the long-term subsidence deformation of the embankment after the formation, and thus the long-term settlement after the completion of the formation. There is no need to make extra measures in anticipation of deformation. (2) A large amount of stabilizing material and time for improvement, which is required when improving the whole embankment material, is not required, and the construction of the embankment support structure is completed early, so that the construction cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an end state of forming an embankment having a predetermined height in a preferred embodiment of a method for forming an embankment according to the present invention.

FIG. 2 is a plan view showing an embedded support plate of the embankment support structure in the above embodiment.

FIG. 3 is a plan view showing another embedded support plate of the embankment support structure in the above embodiment.

FIG. 4 is a cross-sectional view showing a step of driving an embedded support pillar into the first-stage embankment layered body in the above embodiment.

[Explanation of symbols]

 4 Embankment 41A, 41B, 41C Embankment stratified body 411 Embankment spouting layer 412 Drainage material filling part 42A, 42B Embankment support structure 421 Embedded support column 422 Embedded support plate

Claims (3)

[Claims] 1. An embankment layered body having a predetermined thickness in which a plurality of embankment layered layers are sequentially squeezed out and compacted and a drainage material filling section is interposed between these layered embankment layers, and the embankment layered body is vertically moved. An embankment support structure in which a required number of embedded pillars penetrating to are embedded and an embedded support plate is laid over the upper ends of the embedded pillars and the upper surface of the embankment stratification;
A method of forming a fill, characterized by constructing the required number of steps. 2. The embankment construction method according to claim 1, wherein the embedded support plate is a net or a perforated plate made of metal. 3. The method for constructing an embankment according to claim 1, wherein the embedded support plate is constructed by laying a large number of beam-shaped steel plates so as to intersect each other in a grid pattern.