JPS6143485B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for forming underground trenches for constructing underground walls by drilling adjacent and overlapping holes.

A method of constructing underground walls that form structures such as bank protection and retaining walls using plate-shaped or tubular sheet piles.
After using an earth auger excavator to form an excavation hole in the ground to a predetermined depth and inserting a sheet pile, an excavation hole is formed adjacent to this and the existing sheet pile is fitted and connected to the existing sheet pile, and the sheet pile is inserted into this adjacent excavation hole. A construction method has been proposed in which the insertion process is repeated. However, according to this construction method, the auger screw of the earth auger excavator may dig while being curved due to the unevenness of the ground, and depending on the direction of the curvature, the auger screw may hit the existing sheet pile and be damaged, or the sheet pile may be inserted. There were some inconveniences such as making it impossible. In addition, a construction method has been proposed in which the auger crucible is connected with a sheet pile, and this sheet pile is fitted and connected to the existing sheet pile, and the digging force of the auger crucible is transmitted to the sheet pile, and the work is repeated to pull it into the ground as a whole. Although it is efficient because the formation and insertion of the sheet piles are carried out at the same time, it has the drawback that the sheet piles are pulled in from the outside of the excavated hole by the auger crease, so resistance is large and construction cannot be carried out on hard ground.

In addition to constructing underground walls using sheet piles, the present invention can also be used for constructing underground walls by erecting existing members such as concrete panels, and constructing underground walls by inserting reinforcing bar cages and pouring concrete on-site. This makes it possible to excavate and form a medium groove accurately and easily without the above-mentioned drawbacks.

That is, in the present invention, an initial excavation hole of a predetermined depth is formed, a guide member having a support piece at the upper end and an arc-shaped guide surface on one side is inserted into the excavation hole, and the support piece is placed on the ground. A part of the casing of the donut auger excavator is fitted and engaged with the guide surface of the donut auger, and the excavator excavates to form an excavation hole of a predetermined depth, and the guide member is inserted into this excavation hole. The feature is that the operation of inserting and fixing the guide member and guiding the donut auger excavator to form the next excavation hole is repeated, and then the guide member is pulled up and removed.

An embodiment of the present invention will be described below with reference to the drawings. The auger screw 3 of the donut auger excavator 2 is vertically erected and rotated between guides 1 and 1 made of square timbers laid and fixed on the ground surface with a predetermined width. At the same time, it is dug into the ground 5 together with the casing 4 to form an excavated hole 6, and at the same time, cement milk or bentonite aqueous solution is injected from the tip of the auger crucible 3 and mixed and stirred with the excavated soil by the auger crucible 3 to form a fluid slurry 7. (Figure 1). When a predetermined depth is reached, the auger screw 3 and casing 4 are pulled out from the excavation hole 6 to the ground, and the guide member 8 is inserted and fixed into the excavation hole 6 filled with fluidized mud 7.

For example, as shown in FIG. 6, the guide member 8 has a casing 4 on one side of a main body 9 made of a steel pipe with a diameter smaller than that of the borehole 6 and approximately half the length of the borehole 6.
A planar arc-shaped guide surface 10 that fits and engages a part of the main body 9 is formed, and on the opposite side thereof, a restraining projection 11 is formed protruding over almost the entire length, and at right angles thereto, on the upper end surface of the main body 9. It is constructed by fixing and protruding an arm-shaped support piece 12, and when the support piece 12 is placed on a guide 11 and the projection 11 is brought into contact with the hole wall of the borehole 6, the main body 9 and the borehole 6 are inserted into the borehole 6. are hung with their centers aligned, and bolts 14, 14 are inserted into the guides 1, 1 through the mounting holes 13, 13 of the support piece 12 and tightened to fix them.

Next, the casing 4 is placed along the guide surface 10 of the guide member 8, and while creating the fluidized mud 7 in the same manner as described above, the excavated hole 6 is formed adjacently (FIGS. 2 and 4).
When the second excavated hole 6 is formed, the guide member 8 is inserted and its protrusion 11 is inserted into the guide surface 1 of the existing guide member 8.
0, and the support piece 12 is fixed to the guides 1, 1 in the same manner as described above, and the casing 4 is placed along the guide surface 10 of the second guide member 8 to form a third excavated hole.

Thereafter, when the same operation is repeated and several excavated holes 6 that overlap each other are formed, one or an appropriate number of guide members 8 are left, and the guide members 8 that were inserted and fixed earlier are replaced by the guide 1, 1 and pulled up and removed using the hooks 15 provided on the support pieces 12, and the arrows 16 are inserted into the excavated holes 6 in which the guide members 8 were removed and recovered, and the guide members 8 are sequentially fitted and connected.
In parallel with this operation, a new excavation hole 6 is formed by the donut auger excavator 2, and the recovered guide member 8 is inserted into this new excavation hole 6 (FIGS. 3 and 5). In this way, an underground trench 17 consisting of excavated holes 6 overlapping and communicating with each other is formed over a predetermined section, and an underground wall consisting of mutually connected sheet piles 16 is constructed in this underground trench 17. It will be done. The fluid sludge 7 filling the underground trench 17 is either left to harden or replaced with cement mortar, sand, or the like.

Of course, the first excavated hole 6 may be formed with an excavator other than the donut auger excavator.

FIG. 7 shows a different embodiment of the guide member 8, in which a protruding support part is supported by tightly fitting the guides 1, 1 at the upper end of the main body 9 made of a steel pipe having a guide surface 10 and a protrusion 11. 12, 12 protrudingly provided, and the hook 1 provided on the support pieces 12, 12.
5, 15 to suspend or lift the excavation hole 6.
Insertion and removal are performed. FIG. 8 shows a further different embodiment of the guide member 8, in which one side edge of a plate-shaped main body 9 is a restraining protrusion 11, and the opposite edge thereof is a guide surface 10 having a planar arc shape. 10a, and further fix the mounting holes 13, 1 to the upper edge of the main body 9.
3. An arm-shaped support piece 12 having a hook 15 is fixed and protruded, and the guide member 8 shown in FIG.
be treated in the same manner as

In addition, after forming the excavation hole 6 over a predetermined section and creating the underground trench 17, a plate-shaped or tubular sheet pile,
An underground wall may be constructed by erecting concrete panels, etc., or by inserting a reinforcing cage and pouring concrete. In addition to using the guides 1 and 1 for excavated holes such as square timbers, the guide member 8 may also be fixed to a fixing member laid on the ground, and the guide member 8 is no longer necessary. is collected and used repeatedly, but when the section is short, it may be inserted and fixed as is and removed and collected when the underground trench 17 has been formed.

As described above, the present invention provides a guide member having an arc-shaped guide surface that fits and engages a part of the casing of a donut auger excavator, which is inserted into an excavation hole, fixed to the ground by the support piece at the upper end, and Since the work involves repeating the process of drilling an excavator along a guide surface to form a borehole of a predetermined depth, by accurately forming the first borehole, subsequent boreholes will be aligned with adjacent existing boreholes. The excavator excavates automatically and accurately in parallel by descending along the guide surface of the inserted and fixed guide member. In addition, since the guide member is fixed to the ground at its upper end, even if a guide member with a length shorter than the depth of the drilling hole is used, it will not fall to the bottom of the hole and will be fixed in a stable suspended state, allowing the excavator to Not only can it be guided accurately, but it can also be pulled up and removed easily.

When the tip of the excavator is located on the side of the guide member, almost the entire circumference is suppressed by the soil and the guide surface, so the guide surface is used as a ruler to dig straight, and the tip of the excavator is placed on the side of the guide member. When reaching a lower location, by appropriately selecting the length of the guide member relative to the depth of the excavator, the guide member will receive the earth pressure that acts on the excavator from approximately three directions and move it toward the existing excavation hole. This makes it possible to reach a predetermined depth while preventing curvature. For this reason, even if there are areas with uneven hardness in the ground, it is possible to drill without being affected by this and form parallel drilling holes. As a result, the casing fits and slides on the guide surface, preventing accidents such as the auger screw hitting the guide surface and causing damage, and allows excavation to be carried out while preventing the ground from collapsing. To easily form an underground trench in which cages and the like can be inserted and installed accurately without any trouble, regardless of the nature of the ground.

[Brief explanation of the drawing]

1, 2, and 3 are cross-sectional views showing an example of the construction order of the present invention, FIG. 4 is a plan view of FIG. 2, FIG. 5 is a plan view of FIG. 3, and FIG. 7 and 8 are perspective views showing different embodiments of the guide member. 2...Donut auger excavator, 3...Auger screw, 4...Casing, 5...Underground, 6...
Drill hole, 7... Fluid mud, 8... Guide member, 1
0... Guide surface, 12... Support member, 17... Underground trench.

Claims (1)

[Claims] 1. A first excavation hole of a predetermined depth is formed, a guide member having a support piece at the upper end and an arc-shaped guide surface on one side is inserted into this excavation hole, the support piece is fixed on the ground, and the A part of the casing of a donut auger excavator is fitted and engaged with the guide surface, and the excavator excavates to form an excavation hole of a predetermined depth, and a guide member is inserted and fixed into this excavation hole. A method for excavating and forming an underground trench, characterized by repeating the work of guiding a donut auger excavator to form the next excavation hole, and then pulling up and removing the guide member.