JP2864243B2 - Shaft construction method - Google Patents

Description

The present invention relates to a vertical shaft construction method capable of improving work efficiency.

b Prior Art Generally, in construction work, when the target ground is soft, the ground is improved before the main work. As the improvement of the ground, it is usual to impregnate the ground with a hardening material for hardening the target ground.

In recent years, a jet stirring method of ejecting a hardening material and air into the ground at an ultra-high pressure to create a pile-like solid has been widely used.

This injection stirring method comprises an ultra-high pressure pump for pumping a hardening material such as cement, a compressor for supplying air, and a dedicated machine for operating a multi-tube rod having a nozzle at the tip.

A plunger pump is usually used for the ultra-high pressure pump, and the hardener from the mixer is pumped at a high pressure. In addition, the special-purpose machine pulls up while rotating the multi-tube rod, and mixes and injects air and a hardening material from the nozzle at an extremely high pressure.

Thus, a columnar stirring section of the ground and the hardening material is formed in the target ground, and a pile-shaped solid is formed by hardening the hardening material.

This injection stirring method is widely used because of its good workability.However, the diameter of the columnar stirring part depends on the soil conditions and pump performance.
The limit is 2000 ± 200 (mm).

The inner diameter as shown in FIG.
When constructing a 3500 mm shaft, the method shown in Fig. 10 is usually used.

That is, the multiple pipe rods of the operating device are inserted into the bottom 101 of the shaft 100 in the order of a1, a2, a3, and a4 from the a1, and the hardening material is injected to form the columnar stirring unit 102. Next, the multiple pipe rods are inserted as b1..b10 along the circumference of the shaft 100 to form the columnar stirring section 103. Thus, after curing of the curing material,
The inner part of the columnar stirring unit 102 is excavated and taken out to construct a shaft 100 having a predetermined diameter.

c Problems to be Solved by the Invention According to such a conventional shaft construction method, it is extremely difficult to take out the slope portion formed inside the required inner diameter D because the hardening material is hardened. The efficiency was coming down. In addition, since it is necessary to form a large number of columnar stirring sections 102 and 103, it takes a long time to excavate a shaft having a large inner diameter.

The present invention solves the above-mentioned problems, and is a vertical shaft having a continuous wall or a desired relatively large inner diameter (about 3500 mm in inner diameter) in a short time, wherein a gas basin, a sewage / rainwater basin (hole), and a hollow pipe are used. An object of the present invention is to provide a method for constructing a shaft that can construct a shaft having a bottom having a large inner diameter that can be buried.

d Means for Solving the Problems The present invention solves the above problems by rotating an operation rod operated along the depth direction of the target ground, and using an ultra-high pressure from an ejection portion provided on a side surface of the operation rod. In a construction method in which a ground hardening material is injected at a predetermined interval along a substantially perimeter of a shaft to be excavated by a pump to form a columnar stirring portion of the ground and hardening material in the ground, and then the shaft is excavated, the shaft is extruded at an extremely high pressure. Form a bottom agitator with a constant thickness that is larger than the cross-sectional shape of the shaft to be excavated in the ground that will be the bottom of the shaft, and then formed by blowing out the ground hardening material along the periphery of the shaft to be excavated The shape of the columnar stirring portion to be formed is formed only on the outer periphery of the shaft to be excavated, so as to construct a continuous wall with a columnar stirring portion that is continuous only outside the shaft to be excavated by pulling up while rotating the operation rod, In addition, sediment in the continuous wall Removal to a method to build a pit.

e Example Hereinafter, a method of constructing a shaft with a bottom by the construction method of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an apparatus used in the construction method of the present invention, wherein 1 is a dedicated machine for raising and lowering a multi-tube rod 2 or rotating or rotating within a certain angle range, 3 is a mixer 4 and an agitator 5. An ultra-high pressure pump for pumping the mixed hardening material at an ultra-high pressure, a hydraulic unit 6 for driving the ultra-high pressure pump 3, and a compressor 7 for mixing air into the hardening material fed from the ultra-high pressure pump 3. Reference numeral 8 denotes a water tank for supplying water to the mixer 4 by a pump (not shown).

A nozzle (not shown) is provided at the tip of the multiple pipe rod 2 of the special-purpose machine 1 and injects the hardened material pumped by the ultra-high pressure pump 3 into the target ground.

The dedicated machine 1 is provided with a normal drive unit for performing a round operation of the multiple tube rod 2 and a drive unit for rotating and operating the multiple tube rod 2 within a certain angle range. , And can be selectively switched.

The drive unit for the rotation operation is, for example, a unit that reciprocates the rack using a rack and a pinion to rotate the multiple pipe rod 2 right and left. For the reciprocating operation of the rack, for example, projections are provided at both ends of the rack, and by operating a microswitch or the like by this, the rotation traveling of the multiple pipe rod 2 is arbitrarily switched. The rotation angle of the multi-tube rod 2 can be adjusted by changing the operation position of the microswitch by moving the protrusion provided on the rack.

 An example of the ultra-high pressure pump 3 will be described with reference to FIG.

This ultra-high pressure pump 3 has already been filed and has a valve chamber 9.
, A plunger box 12 provided with a plunger 11, and a box 13 provided with a pressure action chamber 13a disposed between the valve box 10 and the plunger box 12.

The valve box 10 has an inlet valve 16 and an outlet valve 17 in an inlet passage 14 and an outlet passage 15 communicating with the valve chamber 9, respectively.
Is provided. Inlet valve 16 and outlet valve
17 is a valve seat 19 in which a valve seat portion is formed in a substantially hemispherical concave surface shape, and a plurality of small holes 18 are formed in the concave surface in the axial direction.
And a valve body 20 having a spherical surface corresponding to the concave shape
And a valve spring 21 for pressing the valve body 20 against the valve seat 19. Above valve seat
The small holes 18 of 19 eliminate the inflow of particles having a certain particle diameter or more.

On the side wall 22 of the valve box 10, a pressure action chamber 13a is provided.
A passage 23 communicating with the inside of the valve chamber 9 is provided in a protruding manner.
A sorter 24 such as a mesh for preventing particles having a certain diameter or more from flowing is provided at the opening end of the pressure action chamber 13a.

The plunger box 12 has a built-in plunger 11 through a V-packing 26 in a cylinder 25, and reciprocates the plunger 11 protruding into the pressure action chamber 13a via a drive mechanism (not shown).

The pressure action chamber 13a is provided with an elastic film 27 that partitions the cylinder 25 side A and the valve chamber 9 side B, and the cylinder side of the elastic film 27 is filled with a working medium 2B such as oil.

Next, a case where a continuous wall as shown in FIG. 3 is constructed using the above-described apparatus will be described.

First, the dedicated machine 1 is placed at the construction position of the continuous wall to be constructed.
Is installed.

Next, a hole is drilled to a predetermined depth at a rod rotation and a traveling speed according to ground conditions (see FIG. 4 (a)). This hole is made to penetrate into the ground 29 by its own weight by a jet from the tip nozzle of the multiple pipe rod 2.

Instead of using the multiple pipe rod, the multiple pipe rod 2 may be inserted into a separately bored hole. After drilling, the multiple pipe rod 2 is lifted upward from the lowermost part of the hole 30 while rotating within a certain angle range (see FIG. 4 (b)). When the high-pressure pump 3 is driven, the hardening material is injected.

The lifting speed and the rotation speed of the multiple pipe rod 2 are set according to the properties and softness of the ground.

The components of the hardening material are mainly composed of cement such as Portland cement, and a mixture of montmorillonite and calcium, a mixture of water reducing materials and the like, and an admixture such as a cement-based soil conditioner are appropriately combined and combined according to the ground. It was mixed with water at a different component ratio.

The structure of the ground is destroyed by the injection of the hardening material, and a columnar pile 31 having a sectorial cross section is formed in the ground as shown in FIG. 4 (c).

The semicircular cross section and the shape pile 31 are formed so that adjacent ones partially overlap each other. by this,
The continuous wall 32 of the columnar pile 31 as shown in FIG. 3 is formed.

FIG. 5 shows a shaft 33 having an inner diameter of a predetermined diameter D. A shaft 33 having a large inner diameter with a bottom for installing a basin or a pipe is constructed by the following method.

First, the multi-pipe rod 2 is inserted at a position at a certain depth along the depth direction of the target ground, and the multi-pipe rod 2 is operated while rotating so that the diameter of the bottom stirring section 34 is at least D or more. The ground hardening material is jetted from the jetting part provided on the side surface of the rod by an ultra-high pressure pump. As a result, a bottom agitating section 34 having a constant thickness 1 larger than the sectional shape of the shaft to be excavated is formed in the ground to be the bottom of the shaft 33. The bottom is indispensable for using a large shaft as a shaft for installing relatively small gas basins, sewage basins, and rainwater basins. Next, the shape of the columnar stirring portion formed by the ejection of the ground hardening material along the peripheral portion of the shaft to be excavated is set so as to be formed only on the outer periphery of the shaft to be excavated.
As shown in the figure, at regular intervals b1 ... b along the periphery of a circle 35 having a diameter D.
The multi-pipe rod 2 is operated at 10 and the circle which is the shaft to be excavated
A fan-shaped columnar pile of about 180 to 200 degrees only on the outside of 35
To form a continuous wall with a continuous columnar stirring unit such that adjacent ones partially overlap each other. Next, earth and sand and the like in the inner portion 37 in the continuous wall surrounded by the columnar pile 36 are removed to construct the shaft 33 having a bottom.

7 and 8 show a construction method of the oval shaft 38. In this case, when constructing the bottom portion 38a of the shaft 38, the multiple pipe rods 2 are shifted from each other by a predetermined distance,
Operate twice at point a '. Then, the multiple pipe rods 2 are rotated at regular intervals at points b1 to b10 along the periphery of the ellipse 39 so that the fan-shaped columnar piles 40 partially overlap each other around the ellipse 39. Then, the side wall 38b of the shaft 38 is constructed.
In this way, soil and the like in the inner portion 41 surrounded by the columnar pile 40 are removed to construct the shaft 36 having an oval bottom.

f Effects of the Invention As described above, the vertical shaft construction method according to the present invention has the following effects.

The output of the ultra-high pressure pump is 2.5 to 3 compared to the conventional pump
As shown in FIG. 5, a single injection and stirring operation has a thickness l and a width D
(Approximately 3500 mm), it is possible to construct a bottom stirring part wider. Next, the injection stirring method using an ultra-high pressure pump was
It is performed within a certain angle range of about 180 to 200 degrees, and a substantially semicircular columnar pile is made so that adjacent ones are continuous,
That is, the construction is made such that the ends of adjacent circles are joined and continuous, or a part of the ends overlap. In this way, by continuously injecting at predetermined intervals along substantially the circumference of the cross-section circle or ellipse, even if the ground is soft, the columnar stirring portion of the ground and hardened material can be easily formed in the ground by a circle or ellipse. A shaft with a bottom can be formed continuously along the outside.
The removal of earth and sand in the inner part of the continuous wall makes it possible to easily construct a shaft having a circular or elliptical bottom, thereby improving work efficiency.

In addition, since the radius of the semicircular columnar pile increases in proportion to the increase in the output of the ultra-high pressure pump, a relatively large bottom shaft is constructed with a smaller number of injections than the conventional one. Therefore, it is possible to improve the work efficiency of excavating the shaft for burying a small rainwater basin (hole) or a hollow pipe.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing each apparatus used in the shaft construction method of the present invention, FIG. 2 is a cross-sectional view showing an ultra-high pressure pump used in the present invention, and FIG. FIGS. 4 (a) to 4 (c) are conceptual sectional views showing the construction order of the shaft, and FIGS. 5 to 8 are constructions of circular or elliptical shafts by the shaft construction method of the present invention. FIG. 5 is a sectional view, and FIGS. 6, 7, and 8 are conceptual views. 9 and 10 show a conventional shaft construction method, FIG. 9 is a sectional view, and FIG. 10 is a conceptual diagram. 1 ... dedicated machine, 2 ... multiple pipe rods 3 ... ultra-high pressure pump, 29 ... ground 31,36,40 ... columnar pile, 32 ... continuous wall 34 ... bottom stirrer, 33,38 ... Shaft

Continued on the front page (73) Patent holder 999999999 Shuichi Fujimori 2-195-5 Kugenumamatsugaoka, Fujisawa City, Kanagawa Prefecture Document JP-A-56-100922 (JP, A) JP-A-53-31311 (JP, A) JP-A-62-174412 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 3/12 102

Claims (1)

(57) [Claims] An operating rod operated along the depth direction of a target ground is rotated, and a vertical shaft for excavating a ground hardening material by an ultra-high pressure pump from an ejection portion provided on a side surface of the operating rod. In the construction method of excavating a shaft by spraying at predetermined intervals along the circumference to form a columnar stirring part of the ground and hardened material in the ground, it is necessary to excavate under extremely high pressure into the ground that will be the bottom part of the shaft Form a bottom agitator with a certain thickness that is larger than the cross-sectional shape of the shaft, and then excavate the columnar agitator formed by the injection of ground hardening material along the periphery of the shaft to be excavated. Construct a continuous wall with a columnar stirring section that is continuous only on the outside of the shaft to be excavated by pulling up while rotating the operation rod so that it is formed only on the outer periphery of the shaft,
A shaft construction method characterized by the construction of a shaft by removing soil from the continuous wall.