JPH03183821A - Construction work by compression of soft ground and structure therefor - Google Patents

Abstract

PURPOSE:To realize a construction work without environmental pollutions due to none of excavated soil, by installing a casing pipe to the depth reaching a bearing layer around a ground anchor and compacting the soft soil inside the casing pipe. CONSTITUTION:A ground anchor, which is composed of a fixed part 4a located at a sufficiently deep place of the bearing substrate 3 of a soft ground 1 and a connected line 4b thereto, is executed. Next, a casing pipe 5 is installed at the depth reaching the surface layer of the bearing substrate 3 in the arrangement containing the line 4b at the center thereof. Next, a water permeable ceramic filter layer 9 is attached to the internal periphery of the casing pipe 5. A supporting plate 6 having almost the same dia. as the inner one of the casing pipe 5 and a metal fixture 14 are placed on the ground surface of casing pipe 5. And further, a center hold jack 7 is installed so that the line 4b pierces the center thereon to form a compressing device 8. And the soft ground 1 is promptly improved to be compacted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a construction method carried out when constructing a building on soft ground such as a reclaimed land, and a method for constructing buildings on soft ground such as reclaimed land. It relates to structures such as compressed ground piles or solid foundations that are constructed by removing earth.

Conventional technology ■ Conventionally, when constructing a building on soft ground, it is common to first construct support piles that reach the support layer, and then construct the underground floor structure of the building on top of these support piles. This is a great way to do it.

Conventionally, a casing pipe was driven into the soft ground, the soil inside the casing pipe was dug out, replaced with concrete, and cast-in-place concrete piles were constructed.
A construction method in which buildings are constructed on cast-in-place concrete piles is generally practiced.

■ The method for promoting consolidation settlement of soft ground described in Japanese Patent Application Laid-Open No. 63-277315 is a type of ground improvement method that replaces the embankment loading method, and involves constructing a sand drain in the soft ground and further installing ground anchors. After construction, a compression V & mount consisting of a support plate and jacks is installed on this ground anchor, and the desired amount of consolidation settlement is achieved by alternately repeating the compression of the ground by this compression device and the natural progression of consolidation by temporary standing. , the content is to construct a structure on the consolidated ground created in this way.

Problems to be Solved by the Present Invention (1) In the case of the construction method using cast-in-place concrete piles as support piles as described in (1) above, the soil inside the casing pipe is dug out and replaced with concrete, resulting in a large amount of excavated soil. Therefore, it is necessary to dispose of the remaining soil. However, in recent years, social conditions have made it extremely difficult to dispose of industrial waste, especially residual soil, so there is a demand for the development of construction methods that require no or very little residual soil disposal.

1) The ground improvement method described in (■) above is more reasonable than the embankment-mounted JL method, and it is recognized that it has a great effect on shortening the construction period. However, there are still some unsatisfactory points regarding the construction method based on this consolidated improved ground, as well as the impact on the outside of the improved ground area, especially the horizontal escape (infiltration) of drainage that accompanies consolidation. There is great concern about the negative effects of fluidization of the surrounding soft ground, and this is an issue that must be resolved.

Means for Solving the Problems (No. 1.2 Invention) As a means for solving the problems of the above-mentioned prior art, the construction method by compressing soft ground according to the present invention has the following features as shown in the drawings: Ground anchors 4a and 4b that reach a sufficiently deep position of the support Ni3 under the soft ground 1 are constructed, and the ground anchors 4
The filtered casing pipe 5 containing b in the center is also installed to a depth that reaches the support layer 3, and the soft! 1il
A compression device 8 consisting of a bearing plate 6 having approximately the same diameter as the inner diameter of the casing pipe and a jack 7 that takes a reaction force to the anchors 4a, 4b is installed on the ground surface of the kli 1, and the compression device 8 is installed to compress the casing pipe. 5 to form a compressed ground pile 2 by compressing and consolidating the soft ground within the supporting layer 3; and a step of constructing the underground structure 10 of the building on the compressed ground pile 2. Characteristics (Figure 1~'!s
Figure 6).

The present invention also provides a method for preventing piles such as underground continuous walls that reach the support layer 3 under the soft ground 1! ! 20 is constructed in a closed loop along the outer periphery of the building, and the above-mentioned mountain stopper is installed on the ground surface of the soft ground 1.
A bearing plate 21 having approximately the same shape and size as the inside shape of the bearing plate 20 is installed, and a steel frame 23 with a filter is constructed for the guide to reach the support layer 3 through the hole 22 of the bearing plate 21. A 4-bit ground anchor 4a that reaches a sufficiently deep position within the support N3 is installed along the steel frame 23, and the bearing plate 2
A pressure 11 device 8 consisting of a jack 7 and the like that takes a reaction force to the ground anchor 4 al 4 b is installed on the upper surface of the ground anchor 1 ,
constructing an underground structure 24 of the building on the bearing slab 21;
And compression! Step by step, the soft ground 1 is compressed and consolidated with the support layer 3 through the bearing plate 21 at 1-8, and the guide steel frame 23 is partially removed.
The present invention is characterized in that a building is constructed using the bearing slab 21 and the compressed ground 25 underneath as a solid foundation.

The working ground anchor 4 al 4 b provides a reaction force necessary for compression and consolidation of the soft ground all by the compression device 8 .

The compressor 8 compresses the inside of the casing pipe 5 with a pressure of approximately 100t/-2! Plate 1 is rapidly consolidated and improved.

The pore water and air squeezed out when the soft ground l inside the casing pipe 5 is compressed and consolidated are transferred to the casing pipe 5.
is discharged upward through a filter 9 provided on the inner surface. In this way, the soil inside the casing pipe 5 is consolidated to about 1/3 of the volume by the volume from which water and air are removed, and becomes a compressed ground pile 2 with strong consolidation (improved soil). The compressed ground pile 2 thus formed has sufficient ability to support a building built on it as a support pile.

In addition, the ground anchor 4 included in the compressed ground pile 2
An 4 b can be used to prevent buoyancy in buildings against groundwater (Fig. 5), to prevent high-rise buildings from falling against earthquakes and wind loads (Fig. 6), or to prevent blistering during root cutting work (Fig. 71!). I) can also be used.

(Invention No. 3.4) As a means for solving the above problem, a structure based on compression of soft ground according to the present invention, as shown in the embodiment in the drawings, has a support layer under the soft ground l. 3. Install the ground anchors 4a and 4b that reach a sufficiently deep position, and
The casing pipe 5 with a filter containing the filter in the center is installed to a depth that reaches the support layer 3, and the soft ground! il
A compression device 8 consisting of a bearing plate 6 having approximately the same diameter as the inner diameter of the casing pipe 6, a jack 7 that takes a reaction force to the anchors 4a and 4b, etc. is installed on the ground surface.
Soft ground inside casing pipe 5! 11 to support layer 3
After compressing and consolidating the bearing plate 6 with the ground anchor 4
It is characterized in that it is a compressed ground pile 2 that is fixed to al 4 b and is constructed by removing the casing pipe 5.

The present invention is constructed by constructing a mountain stop 1!20 in a closed loop along the outer periphery of the building to reach the support layer 3 under the soft ground a1, such as an underground continuous wall, to prevent the soft ground from falling. A bearing plate 21 having approximately the same shape and size as the inner side of the mountain stopper 20 is installed on the ground surface of ll, and a bearing plate 21 with a filter is installed as a guide to reach the support M3 through the hole 22 of the bearing plate 21. A steel frame 23 is constructed, and ground anchors 4 & 4b are constructed along the guide steel frame 23 to reach a sufficiently deep position within the support N3, and a reaction force is applied to the ground anchors 4a, 4b on the upper surface of the bearing plate 21. A compression device 18 consisting of a jack 7 and the like is installed, and the compression device 8 compresses and consolidates the underlying soft ground 1 with the support layer 3 via the bearing plate 21, and It is characterized in that the steel frame 23 is partially removed in stages, and the foundation is a solid foundation composed of the bearing plate 21 and the compressed ground 25 below.

Action il! ! Board anchor 4 as 4 b is compression 1Ri
In addition to providing the reaction force necessary for compression and consolidation of soft ground 1 by t8, measures against buoyancy against groundwater in buildings (No. 51! I)
It provides the reaction force necessary to prevent high-rise buildings from falling due to earthquakes and wind loads (Figure 6), or to prevent wall bulges during root cutting work (Figure 7).

Soft ground 1 inside the casing pipe 5 or under the bearing plate 21
The rJi pore water and air squeezed out when compressed and consolidated are discharged upward through the filter 9 of the casing pipe 5 or the filter of the guide steel frame 23. The compressed ground pile 2 or the compressed soil 11125, which has thus become a strong consolidated top (improved soil), exhibits the performance of supporting a building built thereon as a supporting pile or as a supporting layer.

Example The illustrated invention will now be described in detail.

1 to 3 show process diagrams for forming a compression ground pile 2 on a support N3 in a soft ground 1.

11th! 1 is a sufficiently deep anchorage part of the support layer 3 under the soft ground 1111 (a ground anchor consisting of a bulb 1f04a and a connected PC steel stranded wire 4b) is constructed, and
This shows a stage in which the casing pipe 5 is installed at a depth that reaches the surface layer of the support 113 in an arrangement including the cai strand 4b in the center. The casing pipe 6 is the 11th!
Like IB, a ceramic filter tube 9 with good water permeability is attached to the inner circumferential surface and is equipped with a filter (water channel). However, as shown in FIG. 1C, the filter can be implemented in a double-pipe structure including a porous inner pipe I2 and a partition 13 to form a water channel. The inner diameter of the casing pipe 5 (
A bearing plate 6 and a fixing fitting 14 having approximately the same diameter as the inner diameter of the ceramic filter tube 9 are placed vi, and a plate P
A center hole jack (strong hold jack) 7, through which a Cjll stranded wire 4b passes through the center, is installed, thereby configuring a compression device t8.

21st! 1 indicates a stage in which the compression device 8 is activated to compress and consolidate the soft ground 1 within the casing pipe 5 as much as possible with the support layer 3 directly below it, forming the compressed ground pile 2. . This compression device 8 compresses the ground at a pressure of about 100 t/l/.

If the water and air components contained in soft ground with N1fi of around zero are completely eliminated, its volume will be approximately 1/3
It is said that the following will occur. The pressure va device 8 is subjected to pressure line action with such a volume compression ratio as a target. Thus II! ! The water and air components squeezed out from the gaps between the soil particles of the board are discharged into the free space above the bearing pressure plate 6 through the water channels of the ceramic filter tube 9 forming the inner peripheral surface of the casing pipe 5, respectively. be done. On the other hand, compressed and consolidated soil particles become a hard and strong support. 's2
Reference numeral 16 in the figure indicates a pressure bulb (pressure influence line) generated in the support layer 3 directly below the compression device 8 during compression of the soft ground.

FIG. 3 shows that after the compressed ground pile 2 is formed as described above, the casing pipe 5 and the ceramic filter pipe 9 on its inner peripheral surface are started to be pulled out, and at the same time grout is injected from the tip of the casing pipe 5. The figure shows the stage where the grout material 16 is densely filling the area where the casing pipe 5 was pulled out. Thereafter, the jack 7 exposed by the root cutting work is used to tension the wire 4b from the PCflI, and complete fixation using the wedge mechanism of the fixing fitting 14 is performed by, for example, the strong hold method. After that, the jack 7 is loosened and removed. Also, the PC steel stranded wire 4b is trimmed to a desired length so as to protrude from the fixing fitting 14 (see Fig. 4).
Therefore, the compressed fl completed as above
The underground structure 10 of the building is constructed on top of the compressed soil pile 2, which does not generate any excavated soil in the process of forming the Li-plated pile 2, and the compressed soil pile 2 serves as a support pile that supports the vertical load of the building. It works as (Figure 4).

The concrete usage of the compression ground pile 2 is not limited to the above-mentioned use as a support pile that simply supports vertical loads, but as shown in FIG.
For example, if the PCill stranded wire 4b and the underground structure 10 are constructed using an interlock that connects them so that force can be transmitted, for example, the 51st!
If a deep underground structure 10 is constructed in a place where the underground water level W is high as shown in FIG. Or, if it is used as the foundation of a high-rise building 17 with a tall above-ground part as shown in Figure 6, the same building 1
Since it strongly resists the pull-out force Q against the seismic force or wind load acting on 7, it has the effect of preventing falling.

Furthermore, when the compressed ground pile 2 is installed at the bottom of the root cutting work as shown in Fig. 7, the resistance due to the circumferential friction S of the compressed ground pile 2 causes the groundwater pressure F to reach the bottom of the root cut. By suppressing the rtf1ml blistering that occurs due to this, it is possible to prevent board blistering.

Second Example Next, the 81st! 1 to 11 show an example in which a solid foundation is constructed using compressed ground and a building is constructed on this foundation.

First, in Fig. 8, a retaining wall 20 such as an underground continuous wall that reaches the support N3 under the soft ground all is constructed in a complete closed loop along the outer periphery of the building, and the ground surface of the soft ground 1 is Stop the mountain! ! A bearing plate 21 of approximately the same shape and size as the inner shape of 20
This shows the stage where the . The bearing plate 21 is a single concrete plate that can withstand the compressive action of soft ground and can also serve as a foundation plate. This bearing pressure plate 21 is provided with a large number of holes 22 with appropriate positions and sizes for arranging guide steel frames, which will be described later, and for discharging water and the like removed from the ground.

Also, stop the mountain! ! A filter such as a highly water-permeable ceramic filter plate is provided on the inner surface of the filter 20 as required.

FIG. 9 shows that the guide steel frames 23 with filters are vertically constructed so as to reach the support layer 3 through the holes 22 of the bearing plate 21, and the guide steel frames 23 with filters are installed in the support N3 along each of the guide steel frames 23. Ground anchor 4 that reaches a sufficiently deep position
A and 4b have been constructed, and a compression device 8 consisting of a jack or the like that takes a reaction force to the ground anchor 4b is installed on the upper surface of the bearing plate 21. The guide steel frame 23 is for guiding the sinking of the bearing plate 21 due to ground compression, so to speak, as a parallel movement, and is usually made of steel pipes or H-beams successively joined together. The filter attached to the guide steel frame 23 is implemented by, for example, a configuration in which a ceramic filter tube is attached to a groove of an H-shaped steel. The ground anchor, especially the PCflll strand wire 4b, is also constructed along the groove of the H-shaped steel. The configuration of the compression H position 8 is basically the 21st! Similar to l.

FIG. 10 shows that the underground structure 24 of the building is constructed on the bearing plate 21, and its weight is applied to the bearing plate 21, while at the same time, the compression device 8 is activated to weaken the soft structure beneath it through the bearing plate 21. This shows the stage at which the process of compressing and consolidating the ground 1 with the support layer 3 has started.

Therefore, the load burden on the compression device II'8 is reduced by the added weight of the underground structure 24 of the building.

Water and air components squeezed out from the soft ground l due to compression and consolidation are passed through a pre-prepared filter only within the area partitioned by the retaining wall 2o. It is discharged into the free space above, and the mountain stop wall 2
There is no concern that compression and consolidation of the ground will have an adverse effect on the outer part of the bearing plate 21. Due to the compression and consolidation of all the soft ground by the compression device 8, the amount of settlement of the bearing plate 21 increases, and on the other hand, the amount of settlement on the bearing plate 21 increases. The construction of the underground structure 24 proceeds at the ground level using the reverse construction method. As a result, the upper part of the guide steel frame 23, which protrudes significantly above the bearing plate 21 and becomes an obstacle, has to be joined with successive additions. The guide steel frame 23 is partially removed in stages by a method such as unraveling.

FIG. 11 shows that the compression device 8 compresses and consolidates the underlying soft ground 1 through the bearing plate 21 to a target level to form a compressed ground 25, which is then tensioned by jacking and fixed by the fixing metal fittings. , the solid foundation of the building has been completed with the bearing plate 21 and the compressed ground ff125 below it, and on the other hand, the construction of the underground structure 24 and the above-ground frame 26 above it has largely progressed. In this way, the underground structure 24 of the building can always be constructed at the ground level without performing any excavation work on the soft ground 1, and therefore without generating any excavated earth. It is also a noiseless and vibrationless construction method.

As described in detail in conjunction with the examples above and beyond the effects of the present invention, the construction method and structure by compressing soft ground according to the present invention are as follows:
The construction of compressed ground piles (support piles) does not generate any excavated soil, and the solid foundation construction method does not generate any excavated soil, even when constructing the underground structure of a building, and is noiseless. , tM, since construction can be carried out using the vibration construction method, there is no need to dispose of leftover soil, which is currently a major social issue as a pollution problem, and it also contributes to pollution-free construction.

In addition, by using the strongly improved compressed ground pile 2 as a support pile in construction, or compressed ground! 125 and the bearing plate 21 thereon, a highly stable building can be built on soft ground l.

In particular, it contributes to complete construction work that prevents buildings from floating up, preventing them from falling, and preventing blisters.

4. I! Brief explanation of page 1 Figures 1A, 2 and 3 are cross-sectional diagrams showing the important steps in the construction of compressed soil piles, and Figures 1B and C show the different structures of the casing pipe and filter pipe. Fig. 4 is a sectional view showing an example of the construction of a building using the compressed soil piles, Fig. 5 and Fig. 71! 1 is a cross-sectional view showing different usage examples of the compressed ground pile, and FIGS. 8 to 11 are cross-sectional views showing important steps in the construction method using a solid foundation.

l... Soft ground 3... Support layer 4a, 4b... Ground anchor 5... Casing pipe 6... Bearing plate 7...
・Jacket 8... Compression device 10... Underground structure 20... Mountain stop wall (underground tower) 21... Bearing plate 23... Steel frame for guide 6 Figure Figure 1 Renkomamine Figure 1 Figure 1 Procedure correction Lu (Blade side flat bottom March 28, 2013)

Claims (1)

[Scope of Claims] [1] A ground anchor that reaches a sufficiently deep position in the supporting layer under the soft ground is installed, and a casing pipe with a filter that includes this ground anchor in the center is extended to a depth that also reaches the supporting layer. A compression device consisting of a bearing plate having approximately the same diameter as the inner diameter of the casing pipe and a jack that takes a reaction force to the anchor is installed on the surface of the soft ground, and this compression device is used to compress the soft ground inside the casing pipe. compression,
A construction method by compressing soft ground, characterized by comprising the steps of: consolidating to form compressed soil piles; and constructing an underground structure for a building on the compressed soil piles. [2] A retaining wall such as an underground continuous wall that reaches the supporting layer under the soft ground is constructed in a closed loop along the outer periphery of the building, and the inner shape of the retaining wall is approximately isomorphic,
Install a bearing plate of the same size, construct a steel frame with a filter for guiding to reach the support layer through the hole in the bearing plate, and reach a sufficiently deep position within the support layer along the guide steel frame. constructing a ground anchor, installing a compression device consisting of a jack or the like to take a reaction force on the ground anchor on the upper surface of the bearing slab, and constructing an underground structure of the building on the bearing slab;
The process of compressing and consolidating the soft ground through the bearing slab with a compression device and the partial removal of the guide steel frame is carried out in stages, and the bearing slab and the compressed ground underneath are compressed and consolidated into a solid foundation. A construction method that uses compaction of soft ground, which is characterized by the construction of buildings. [3] Construct a ground anchor that reaches a sufficiently deep position in the supporting layer under the soft ground, and install a casing pipe with a filter that includes this ground anchor in the center to a depth that also reaches the supporting layer. A compression device consisting of a bearing plate with approximately the same diameter as the inner diameter of the casing pipe and a jack that takes a reaction force to the anchor is installed on the ground surface, and the compression device compresses the soft ground inside the casing pipe.
A compression ground pile for compressing soft ground, which is constructed by compacting, fixing a bearing plate to a ground anchor, and removing the casing pipe. [4] A retaining wall such as an underground continuous wall that reaches the support layer under the soft ground is constructed in a closed loop along the outer periphery of the building, and the inner shape of the retaining wall is approximately isomorphic,
Install a bearing plate of the same size, construct a steel frame with a filter for guiding to reach the support layer through the hole in the bearing plate, and reach a sufficiently deep position within the support layer along the guide steel frame. A ground anchor is installed, and a compression device consisting of a jack, etc. that takes a reaction force to the ground anchor is installed on the top surface of the bearing slab, and the compression device compresses and consolidates the soft ground underneath through the bearing slab. and partial removal of the guide steel frame in stages, and the solid foundation is made up of the bearing slab and the compressed ground below it.