JPH0213610A - Water-stopping and sheeting wall construction method - Google Patents

Abstract

PURPOSE:To unit a sheet pile and a rock bed layer in one body and prevent percolation of underground water from the driving-in portion of the sheet pile, by digging the rock bed layer, making concrete in the digged hole and driving the sheet pile therein. CONSTITUTION:A digging casing 6 having a digging cutter is advanced downward to the rock-bed line 5 on the upper surface of a rock bed layer 4 through a gravel layer 3. Then, the rock bed layer 4 is digged till a specified depth by a digging means having a digging screw, mortar is filled in the digged hole of the rock bed layer 4 and churned, and concrete 12 is made using digged rock as aggregate. Then sand or earth and sand is thrown into the digging casing 6 and the casing 6 is drawn up, and then a steel sheet pile 1 is built in the digged hole and is driven into the concrete 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a construction method for constructing an effective water-stop earth retaining wall on permeable ground such as a gravel layer as a civil engineering foundation work.

[Conventional technology]

As a method of constructing water-stop earth retaining walls, a method is often adopted in which steel pipe sheet piles are erected in succession and these are used to form columnar walls.

FIG. 8 shows an example of this, in which a steel pipe sheet pile 1 is provided with a joint 1a along the longitudinal direction of the side surface.
The sheet piles 1 are sequentially arranged in parallel via a. 2 in the figure shows an excavated hole for erecting this steel pipe sheet pile 1.

In order to form a water-stop earth retaining wall using the sheet piles 1 in a place where there is water such as a river, the excavated hole 2 is formed in a gravel layer at the river bottom.

In addition, the process of erecting the steel pipe sheet pile 1 involves forming an excavation hole 2 in the ground using an auger or the like, filling the excavation hole 2 with sand, etc. to create a plurality of continuous column holes, and then Insert the tips of the sheet piles 1 into the holes and connect them one by one.

[Problem to be solved by the invention]

The excavation hole 2 is formed up to the bedrock layer below the sand, and the sheet pile 1 is
If the walls are not built to this extent, it will not be possible to obtain sufficient supporting force, but if sand or the like is interposed between them, the supporting force will be difficult.

Further, in a ground where there is groundwater, the hole wall collapses when sand is poured into the excavated hole 2, making it difficult to erect the sheet pile 1 completely to the bedrock layer. If the sheet pile 1 is incompletely embedded in this way, there is a risk that groundwater will permeate from the lower end of the sheet pile 1 and the water supply effect will be lost.

An object of the present invention is to provide a rational water-stopping earth retaining wall construction method that can eliminate the disadvantages of the conventional examples and provide ideal supporting force and a complete water-stopping effect to the sheet piles to be erected.

[Means for Solving the Problem] In order to achieve the above-mentioned object, the present invention forms a boundary between a permeable layer such as a sand or gravel layer and an impermeable layer such as a bedrock layer using an excavation casing having a cutting blade at the tip. Excavate to the base rock line while removing the earth and sand inside the casing upwards by any means, and then excavate to the base rock line -5.
A drilling means with a drilling screw at the tip of the rod is inserted into the excavation casing whose tip has reached, and the rock layer is excavated to a predetermined depth, and cement milk or mortar is filled up to the vicinity of the base rock line and stirred to excavate. Concrete is made using the excavated rock as aggregate, sand or earth is poured into the excavation casing, and the casing is pulled out, thus forming a continuous excavation hole filled with sand or earth and concrete below it. , the gist is to construct a continuous wall by erecting sheet piles into the excavated hole.

[Effect]

According to the present invention, the bedrock layer that becomes the joist of the sheet pile is reliably excavated by an excavating means having an excavating screw, and the excavated rock becomes finely crushed high-quality aggregate.

Since the sheet piles are embedded in concrete using this aggregate, they become integrated with the bedrock layer, preventing groundwater from penetrating through the joists and providing a large supporting force after the concrete hardens.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figures 1 to 7 are longitudinal sectional front views of each process showing one embodiment of the water-stop earth retaining wall construction method of the present invention, in which 3 is a gravel layer which is a permeable layer, and 4 is an impermeable layer below it. 5 indicates the bedrock line that forms the boundary between these layers. In this embodiment, the gravel layer 1 forms the bottom of a river or the like, and a water stop wall is constructed underwater.

As shown in Fig. 1, the tip has a digging blade 6 such as a drilling bit.
The gravel layer 1 is excavated using the excavation casing 6 having the shape a.

In the figure, reference numeral 7 denotes a Heas machine that rotationally drives a 20 casing 6, which is installed on a pedestal 8 and has a drive device IO that is moved up and down by a jack 9. Although not shown, the drive device includes a chuck mechanism that chucks the outer periphery of the casing 6 and a hydraulic motor that rotates this chuck mechanism.
The casing 6 passing through the center of the drive device 10 is locked by a chuck mechanism and rotated by the rotational force of a hydraulic motor.

Further, when excavating with the excavation casing 6, although not shown in the drawings, the earth and sand within the casing 6 is discharged upward by suspending an excavation bucket or any other excavation and discharge means into the casing 6.

In this way, when the tip of the excavation casing 6 reaches the base rock line 5, the excavation is stopped there.

Next, as shown in FIG. 2, the excavating means 11 provided with the excavating screw 11c having the excavating blade 11'b at the tip of the hollow rod lla is inserted into the excavating casing 6, and as shown in FIG. Then, the bedrock layer 4 is excavated to a predetermined depth necessary for rooting.

This excavating means 11 is more suitable for rock excavation than a normal earth auger because it has a digging blade 11b, and the excavated rock can be crushed into fine pieces, which are suitable for use in concrete as will be described later. Can be used as aggregate.

Further, the excavating means 11 may have its own driving device, but a drum 11d having approximately the same diameter as the casing 6 may be provided at the upper end of the rod lla, and the drum 11d may be chucked and rotated by the driving device 10. You can also do it.

After excavating bedrock layer 4 as described above,
Cement milk or mortar is poured out from the tip of a and the excavated rock is stirred to form concrete 12 in the bedrock layer 4.

In this case, the pouring of cement milk or mortar may take place during the excavation by the excavation means 11, or it may take place completely after the excavation. The screw 11c can be used as a stirring blade to stir the excavated rock used as aggregate.

Thereafter, as shown in FIG. 5, the rock layer 4 is further excavated from the base rock line 5 to about the depth of the concrete 12 using the excavation casing 6. This step is to make the pore diameter in the rock layer 4 the same as the pore diameter in the upper part thereof, and is not necessarily necessary.

Then, as shown in FIG. 6, while the excavation casing 6 is pulled up, sand or earth 13 is poured into it to fill the excavation hole above the concrete 12.

As shown in FIG. 8, two or three excavated holes filled with concrete meshes 2 and sand or earth and sand 13 are formed in succession, partially overlapping each other, until the concrete 12 is uncured. At this stage, as shown in FIG. 7, the steel pipe sheet pile 1 is erected with its tip sufficiently inserted into the bedrock layer 4. Incidentally, the steel pipe sheet pile 1 has the joints 1a, as explained in FIG. 8, and can be used to connect them in parallel in sequence.

〔Effect of the invention〕

As described above, in the water-stop earth retaining wall construction method of the present invention, the rock layer that will become the thick part of the sheet pile is made of concrete in an excavated hole and the sheet pile is embedded in this. The sheet piles are integrated with the bedrock layer, preventing groundwater from seeping through the sheet pile joists and providing a complete water stoppage. Additionally, after the concrete hardens, this area provides a strong support for the sheet piles.

A series of these steps can be carried out in a continuous manner without any interruptions, thereby streamlining the construction process and shortening the construction period.

[Brief explanation of the drawing]

FIGS. 1 to 7 are longitudinal sectional front views showing each step of an embodiment of the water-stop earth retaining wall construction method of the present invention, and FIG. 8 is a plan view showing an example of a water-stop earth retaining wall made of steel pipe sheet piles. 1... Steel pipe sheet pile 1a... Joint 2... Excavation hole 3... Gravel layer 4... Rock layer 5... Baseline line 6... Excavation casing 6a
... Drilling blade 7 ... Base machine 8 ... Frame 9 ... Jacket 10 ... Drive device 11 ...
- Excavation means 11a... hollow rod 11b...
・Drilling blade 11c...Drilling screw lid・
...Drum 12...-Concrete 13...
Sand or soil Figure 6 Figure 7 Figure 8

Claims (2)

[Claims] (1) Sand,
Excavation is carried out until the base rock line that forms the boundary between a permeable layer such as a gravel layer and an impermeable layer such as a bedrock layer, while removing the earth and sand inside the casing upwards by any means, and the tip reaches the base rock line. A drilling means with a drilling screw at the tip of the rod is inserted into the casing to excavate the rock layer to a predetermined depth, and cement milk or mortar is filled up to the vicinity of the base rock line and stirred to remove the excavated rock. Make concrete as a material, pour sand or earth into the excavation casing, pull out the casing, and in this way form a continuous excavation hole filled with sand or earth and concrete below it. A water-stopping earth retaining wall construction method characterized by constructing a continuous wall by erecting sheet piles. (2) The water-stop earth retaining wall construction method according to claim 1, wherein after concrete is made in the bedrock layer, the excavation casing is excavated from the base rock line to a predetermined depth into the bedrock layer and then pulled out.