JP2000290995A - Method for constructing underground wall through ground improvement and device for use therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a soil cement underground wall having no arcuate projecting part on at least one side of its wall surface. SOLUTION: A ground is improved by means of a device including a high- pressure jet shaft 12, multi-axis rotary drives for rotating the high-pressure jet shaft, and a nozzle 14 at the lower end of a shaft member for ejecting cement milk under high pressure in a direction perpendicular to an axis. A soil mortar underground wall is thereby constructed. As the high-pressure jet shaft 12 is rotated, the cement milk is ejected from the nozzle 14 under high pressure, and as bouncing plates spaced apart from one another by predetermined lengths are held on one or both sides of the nozzle 14, the high-pressure jet shaft 12 is propelled downward into a ground to form the underground wall as the range of ground improvement by high-pressure fluid is regulated by the bouncing plates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing an underground wall by ground improvement and an apparatus used for the method.

[0002]

2. Description of the Related Art A multi-axial soil cement column wall method is one method for constructing an underground wall. In this method, for example, a multi-axial auger machine 60 as shown in FIG. A column wall as shown in 5 is constructed. Here, the multi-axis auger machine 60 includes a base machine 63, a mast 61 erected by the base machine 63,
Drive device 62 that moves up and down along the axis, a multi-axis coupling body 64 that is rotated by the multi-axis drive device 62, and a vibration-reducing device 66 for suppressing the deflection of the multi-axis coupling body 64
And Then, in the multiaxial connector 64, the plurality of auger shafts 67 are connected at predetermined intervals by the connecting member 65,
An auger head 67c is provided at the lower end of each auger shaft 67. Further, each auger shaft 67 has a moving blade 67b for moving the excavated earth and sand upward, and a kneading blade 67a for mixing the excavated earth and sand with cement milk. Are formed.

In the above multiaxial soil cement column wall method,
First, while augmenting cement milk from each auger head 67c, drilling a hole by rotating the auger shaft 67, stirring earth and sand and cement milk to form a soil cement column, and the soil cement column H-shaped steel 53 or I-shaped steel as a core material is inserted into the inside. Next, by continuously connecting such soil cement column bodies while overlapping their ends, a column wall can be constructed.

[0004]

The soil cement column walls constructed by the above-mentioned conventional method project on both sides in an arc shape as shown by a hatched portion 55 in FIG. 5, and the projected hatched portion 55 It is dangerous to use the soil-cement column wall as a retaining wall for underground excavation, because it hinders the work of erection of the girder and it is easily dried and peeled off. Therefore, conventionally, one of the hatched portions 55 is cut off to flatten the wall surface. However, this cutting operation is troublesome and troublesome. Further, in the soil cement column row wall, structural strength can be expected only in the width portion indicated by the reference numeral 51, and the hatched portion 55
Has a drawback that the material is wasted because structural strength cannot be expected.

In order to construct a soil cement column wall, instead of using the multi-axis auger machine 60, high-pressure cement milk is spouted from a nozzle provided at the lower end of the shaft member to rotate the shaft member. It is also possible to use a device for improving the ground in a columnar shape by propulsion while so-called, a so-called high-pressure injection-type ground improvement device. However, in this case, the same problem as described above occurs.

The present invention focuses on the above-mentioned problems of the prior art,
It is an object of the present invention to provide a method of constructing a soil cement underground wall having no arc-shaped overhang on at least one side of the wall.

Another object of the present invention is to provide an apparatus for constructing an underground soil cement wall having no arc-shaped overhang on at least one side of the wall.

[0008]

In order to solve the above-mentioned problems, the present invention provides a shaft member, a driving means for rotating the shaft member, and a direction intersecting the shaft at the lower end of the shaft member. A method of constructing an underground wall by using a device having a nozzle that ejects a fluid containing a hardening material at a high pressure, thereby constructing an underground wall, wherein the hardening material is discharged from the nozzle while rotating the shaft member. Injecting the fluid containing at a high pressure, holding the plate at a predetermined distance on one or both sides of the nozzle while propelling the shaft member below the ground, regulating the ground improvement range by the high pressure fluid with the plate An underground wall construction method characterized by forming an underground wall is provided. In the method of the present invention, while holding the plate at a predetermined distance on one or both sides of the nozzle, while propagating the shaft member below the ground to improve the ground, fluid such as cement milk injected at high pressure is The surface on one or both sides of the underground wall can be formed to be flat by being bounced off the plate surface.

Here, the fluid containing the curing material includes:
The ground can be cut by ejecting it from the nozzle with high pressure in the ground, and after a lapse of a predetermined time, it hardens together with the earth and sand mixed at the time of cutting the ground and expresses a compressive strength of a predetermined level or more. For example, a cement milk, a water glass-based injection material, or a urethane-based injection material can be used.

According to the present invention, there is provided an apparatus used for ground improvement, wherein a plurality of auger shafts are juxtaposed, and a nozzle for ejecting a high-pressure fluid in a direction intersecting the material axis is provided at a lower end between the auger shafts. A high-pressure jet shaft is provided side by side, a plate is provided on one or both sides of the nozzle and separated by a predetermined length, and a connecting member for rotatably connecting the plurality of auger shafts and the high-pressure jet shaft is provided. The present invention provides a multiaxial connector characterized by the above. Here, the plate may be formed in a long rectangular shape. In this case, a plurality of auger shafts are arranged so as to face the nozzle and to be orthogonal to the material axis of the high-pressure jet shaft. May be locked at the lower end.

In the multiaxial connector according to the present invention, if the high pressure fluid is jetted from the nozzle in a direction intersecting the material axis while rotating the plurality of auger shafts, the ground is cut by the auger and the ground is improved by the high pressure fluid. The high-pressure fluid ejected from the nozzle is rebounded by a plate provided at a position facing the nozzle, so that the ground improvement range is limited, and one or both wall surfaces of the underground wall are formed flat.

Further, in the present invention, a plurality of cores for inserting into the underground wall formed by the method according to claim 1 are provided.
A high-pressure jet shaft connected at a predetermined interval by a connecting member in a substantially parallel manner and provided with a nozzle at a lower end for ejecting a high-pressure fluid in a direction intersecting the material axis, between the plurality of core materials, The nozzles are arranged side by side so as to be located below, a cutting bit is provided at the lower end of the high-pressure jet shaft, and a plate body separated by a predetermined length on one side or both sides at a position facing the nozzle,
A multiaxial connector including a core material, wherein a driving device for rotating the high-pressure jet shaft is provided at an upper end of the plurality of core materials.

In the multiaxial connector including the core material of the present invention, a cutting bit is provided at the lower end of the high-pressure jet shaft, and the lower end projects below the lower end of the core material. If a high-pressure fluid is ejected from a nozzle in a direction intersecting the material axis while hanging the high-pressure jet shaft with a driving device while suspending and lowering it at a planned construction point on the inner wall with a crane or other lifting machine,
The ground is cut by the cutting bit and the ground is improved by the high-pressure fluid, and the multi-axis connected body sinks to the improved ground by the weight of the core and the drive unit. Then, the high-pressure fluid ejected from the nozzle is rebounded by a plate provided at a position facing the nozzle, so that the ground improvement range is limited, and one or both wall surfaces of the underground wall are formed flat. Therefore, in the multi-shaft connector including the core material of the present invention, there is no need for a large-scale excavator such as an auger, and a simple lifting machine capable of lifting these multi-shaft connectors and hanging them down to a predetermined point is provided. If you can, you can build an underground wall.

Here, an H-shaped steel, an I-shaped steel, a steel pipe or a precast concrete member can be used as the core material. The connecting member may be any member that can connect a plurality of core members substantially in parallel at a predetermined interval. The connecting member may be provided with a member that holds a high-pressure jet shaft. Further, the plate body may be formed in a long rectangular shape. In this case, the plate body is disposed at a lower end of a plurality of core materials in an arrangement so as to be opposed to the nozzle and orthogonal to the material axis of the core material. The plate may be fixed, and the lower end of the long plate may be formed into a sharp edge. By forming the cutting edge like this, the insertion of the core material into the ground can be promoted.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the accompanying drawings, but the present invention is not limited to these embodiments. 1 to 3 show only the lower end of the multiaxial connector 10 of the present invention. The multiaxial connector 10 has a plurality of auger shafts 11 arranged in parallel and a high-pressure jet shaft 12 arranged in parallel between the plurality of auger shafts 11.
And the high-pressure jet shaft 12 are connected by a connecting member 13 so as to be rotatable, respectively.
An improved regulating member 20 is arranged and formed at a position corresponding to the nozzle 14 formed at the lower end of 2.

Here, an auger head 15 is connected to the lower end of the auger shaft 11, and an interval between adjacent auger shafts 11 is determined so as to be as close as possible within a range in which adjacent auger heads 15 do not come into contact with each other. Although not shown in FIG. 1, the auger shaft 11 may be provided with moving blades 67b and kneading blades 67a as shown in FIG.

At the lower end of the high-pressure jet shaft 12,
A pair of nozzles 14 oriented in a direction substantially perpendicular to the material axis
And a pipe (not shown) is provided in the high-pressure jet shaft 12 so as to communicate from the upper end to the lower end. The pipe is connected to the nozzle 14 at the lower end, and cement milk or the like is provided at the upper end. A pipe (not shown) communicating with a ground improving agent supply device (not shown) for sending out the ground improving agent at a high pressure is connected. The high-pressure jet shaft 12 is arranged in the middle of the adjacent auger shaft 11.

The improved restricting member 20 includes a pair of rectangular plates 21 arranged on both sides of the high-pressure jet shaft 12 at positions opposite to the nozzles 14, a tube 23 fitted around the auger shaft 11, and There is provided a connecting member 22 for connecting the pipe member 23 and the pair of plate members 21 respectively, and the pair of plate members 21 are fixed at intervals substantially the same as the diameter of the turning circle of the auger head 15.

The operation of the multiaxial connector 10 of the present invention will be described. The multiaxial connector 10 of the present invention is shown in FIG.
In the multi-axis auger machine 60 shown as a conventional example, the multi-axis connector 64 is replaced with a multi-axis rotation driving device 62 and used. In the multiaxial connector 10, the auger shaft 11 and the high-pressure jet shaft 12 are rotated by the multiaxial rotation drive device 62, and while the hole is drilled by the auger head 15, cement milk as a ground improving agent is supplied from the nozzle 14 at a high pressure. Gushing. At this time, the auger head 15 is denoted by reference numeral 1 in FIG.
Holes are drilled while drawing the circumference as shown in 5 and the ground is left uncut between the adjacent circumferences 15. The ground left behind is improved by the cement milk injected from the nozzle 14. You. In other words, the cement milk injected from the nozzle 14 improves the ground left uncut between the pair of plate bodies 21 and is rebounded on the inner surface of the plate bodies 21. Regulated at 21 intervals,
Further, the cement milk injected at a high pressure is indicated by a dotted line 3 in FIG.
After reaching the 0 position, the ground is also improved here. And
If the ground is improved to a predetermined depth and the multiaxial connector 10 is pulled out upward and an H-shaped steel 33 as a core material is inserted, one element of the soil cement ground wall can be formed. By arranging these elements continuously with their ends overlapping, a soil cement underground wall having flat wall surfaces on both sides can be constructed.

Next, with reference to FIGS. 6 and 7 (a) and 7 (b), the structure of the multiaxial connector 35 including the core material of the present invention will be described. In the multiaxial connector 35, a plurality of H-shaped steels 36 as a core material are arranged in parallel and connected by a connecting member 26, and the high-pressure jet shaft 12 is arranged in parallel between the plurality of H-shaped steels 36. Of the high pressure jet shaft 12
The upper end of the high-pressure jet shaft 12 is connected to the multi-axis rotary drive device 27, and the corresponding position of the nozzle 14 formed at the lower end of the high-pressure jet shaft 12 is fixed. , A long plate 25 is arranged.

Here, the interval between the plurality of H-shaped steels 36 is
It is appropriately determined according to the structural strength required for the underground wall to be constructed. The high-pressure jet shaft 12 has the same structure as the high-pressure jet shaft 12 shown in FIGS. 1 to 3 except that a cutting bit 16 is provided at the lower end thereof.
2 extends in the middle of the adjacent H-shaped steel 36 and the nozzle 14
Are located below the lower end of the H-section steel 36. Further, the plate 25 is formed in a long rectangular shape,
As shown in FIG. 6, the plate body 25 is fixed to the lower ends of the plurality of H-shaped steels 36 such that the lower end side is located below the nozzle 14. The lower edge 25a of the plate body 25 is formed in a sharp edge shape.

Next, the operation of the multiaxial connector 35 including the core material of the present invention will be described with reference to FIGS. The multi-axis connector 35 of the present invention is lifted by a lifting machine such as a crane via a locking member 28 provided on the multi-axis rotation drive device 27, and is suspended at the scheduled construction point of the underground wall. Of the cutting edge 25a and the cutting bit 16
Is supported in contact with the ground surface. Then, the high-pressure jet shaft 12 is rotated by the multi-axis rotation drive device 27, and while the ground is cut by the cutting bit 16, the cement milk is jetted from the nozzle 14 at high pressure. At this time, the nozzle 14
Is rebounded on the inner surface of the plate 25, so that the ground improvement range is limited, and the wall surfaces on both sides of the underground wall are formed flat. Thus, the cutting bit 16
When the ground is improved with cement milk while cutting the ground with, the multiaxial connector 35 gradually sinks into the improved ground due to its own weight. Then, when the multi-axial connector 35 sinks to a predetermined depth, the fixed state between the upper end of the H-shaped steel 33 and the multi-axial rotary drive 27 is released, and only the multi-axial rotary drive 27 and the high-pressure jet shaft 12 are released. Is pulled upward, the plurality of H-shaped steels 36 are left in the ground as core materials, and one element of the soil cement ground wall is formed. By arranging these elements continuously with their ends overlapping, a soil cement underground wall having flat wall surfaces on both sides can be constructed.

[Brief description of the drawings]

FIG. 1 is a front view partially showing a multiaxial connector according to the present invention.

FIG. 2 is a cross-sectional view taken along the dashed line II-II of FIG.

FIG. 3 is a vertical sectional view taken along a dashed line III-III in FIG. 2;

FIG. 4 is a plan view of an underground wall constructed by the method of the present invention.

FIG. 5 is a plan view of a column wall constructed by a conventional method.

FIG. 6 is a front view of a multiaxial connector including a core material of the present invention.

7A is a cross-sectional view taken along a dashed line VIIa-VIIa in FIG. 6, and FIG. 7B is a dashed line VIIb-B in FIG.
FIG. 7 is a longitudinal sectional view taken along a line VIIb.

8 is a cross-sectional view showing one step in a method of constructing an underground wall using the multiaxial connector shown in FIG.

FIG. 9A is a side view of a conventional multi-axis auger machine, and FIG. 9B is a front view of a multi-shaft connector and a rotary driving device in the multi-axis auger machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Multi-axis connection body 11 Auger shaft 12 High-pressure jet shaft (shaft member) 13 Connection member 14 Nozzle 16 Cutting bit 21 Plate 25 Plate 25a Blade 26 Connection member 27 Multi-axis rotation drive (drive means) 35 Multi-axis connection Body (multi-axis connection including core) 36 H-section steel (core) 62 Multi-axis rotary drive (drive means)

Claims (3)

[Claims] An apparatus comprising: a shaft member; driving means for rotating the shaft member; and a nozzle for ejecting a fluid containing a hardening material at a lower end of the shaft member in a direction intersecting the shaft at a high pressure. A method for improving the ground, thereby constructing an underground wall, wherein a fluid containing a hardening material is jetted at a high pressure from the nozzle while rotating the shaft member, and the shaft member is propelled below the ground. A method of constructing an underground wall, comprising: holding a plate at a predetermined distance on one or both sides of a nozzle; and controlling an area of ground improvement by high-pressure fluid with the plate to form an underground wall. 2. An apparatus used for ground improvement, comprising a plurality of auger shafts arranged side by side, and a high-pressure high-pressure nozzle having a nozzle at a lower end for ejecting a high-pressure fluid in a direction intersecting the material axis between the auger shafts. A jet member is juxtaposed, a plate is provided at a predetermined distance on one or both sides of the nozzle, and a connecting member for rotatably connecting the plurality of auger shafts and the high-pressure jet shaft is provided. Characteristic multi-axis connector. 3. A plurality of core members to be inserted into the underground wall formed by the method according to claim 1, which are connected substantially in parallel at predetermined intervals by connecting members, and a high-pressure fluid is provided in a direction intersecting the material axis. A high-pressure jet shaft with a nozzle at the lower end
The nozzles are juxtaposed below the lower end of the core material between the plurality of core materials so that a cutting bit is provided at the lower end of the high-pressure jet shaft. A multi-axial connector including a core member, wherein plate members separated by a predetermined length are provided on both sides, and a driving device for rotating the high-pressure jet shaft is provided at an upper end of the plurality of core members.