JPH0432169B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention aims to excavate in two stages a stratum in which the upper layer is prone to collapse and the lower layer has cracks, etc., making it impossible to use a stabilizing liquid. This invention relates to a construction method for a joint part of a continuous underground wall when constructing an inner wall.

[Conventional technology]

Constructing continuous walls such as concrete with reinforcing bars or steel frames inserted into the ground as water-stop walls, earth retaining walls, or structural walls using the muddy water construction method is a construction method that causes less pollution as an alternative to driving-in sheet pile walls. This is commonly done in construction.

This is done by filling the excavation hole with muddy water to prevent the excavated wall from collapsing while excavating the ground to the required depth, for example, into an oval cross-section. By pouring materials to construct unit walls (elements) and repeating this construction method, a continuous underground wall with continuous elements is constructed.

[Problem that the invention seeks to solve]

However, such conventional methods for constructing continuous underground walls can be applied when the ground to be constructed is simply a stratum that easily collapses, but if the lower layer following this stratum has cracks, etc. There was a problem in that it was difficult to apply conventional methods in geological formations where a water loss phenomenon occurs in which the stabilizing solution poured into the ground suddenly flows out into the ground.

This invention was made in view of the problems of the conventional art, and it is possible to install a guide after pulling out an interlocking pipe after dry excavating a groove in the lower layer where stabilizing liquid cannot be used and pouring concrete. The purpose is to solve the above problems by using a construction method that closes the hole with a water-stopping member.

[Means for solving problems]

When constructing a continuous underground wall in a stratum that has an upper layer that is easy to collapse and a lower layer that has cracks or the like and cannot be used with a stabilizing liquid, the above-mentioned upper layer at the planned construction location of the underground wall is A stabilizing liquid is used to prevent the wall from collapsing while a guide hole is excavated and a hollow is excavated to form an upper groove, and then a guide hole is excavated and hollowed out in the lower layer below the upper groove without using a stabilizing liquid. A hollow excavation is performed to form a lower groove, an interlocking pipe is installed at the side end of a deep groove formed by this groove and the upper groove, concrete is poured into the groove, and after this concrete hardens,
After pulling out the interlocking pipe, a water stop member is installed near the concrete top of the guide hole where the interlocking pipe was pulled out to prevent the stabilizing liquid from flowing into the lower layer, and then above the water stop member. The present invention provides a construction method for a joint part of a continuous underground wall, in which the guide hole part is filled with stabilizing liquid and an upper groove for the next element is excavated.

[Effect]

A stabilizing liquid is used in the upper layer, which is likely to collapse, to prevent the wall from collapsing, and a guide hole is excavated and a hollow is excavated to form an upper groove, and the stabilizing liquid in this groove is removed. Next, by performing dry guide hole drilling and hollow drilling without using a stabilizing liquid in the lower layer below this groove, a lower groove is formed vertically continuous with the upper groove. After installing interlocking pipes at the side ends of this continuous deep groove, concrete is placed in the lower groove, and after the concrete hardens, the upper groove above the concrete is backfilled with sand to construct the preceding element. . Thereafter, the interlocking pipe is pulled out, and a water-stopping member is installed near the concrete top of the guide hole created at the site where the interlocking pipe was pulled out to prevent the stabilizing liquid from flowing into the lower layer. Next, when the guide hole portion above the water stopper member is filled with a stabilizing liquid, this guide hole portion becomes a joint portion prepared as a guide hole for forming the next upper groove for the element.

〔Example〕

The present invention will be explained below based on the drawings. 1 to 16 are diagrams showing an embodiment of the present invention in the order of steps, in which figure a is a top view and figure b is a longitudinal cross-sectional view. Figure 17 is a cross-sectional view of the ground on which the underground wall will be constructed.
18 and 19 are detailed views of the water stop member in FIGS. 14 to 16b.

In the figure, E ₁ is the upper stratum that is prone to collapse;
E ₂ indicates the lower stratum with cracks, etc., and E ₃ indicates the impermeable layer. 1 is an earth auger that excavates the ground vertically to form guide holes; 2 is a club bucket for excavating the soil between adjacent guide holes, so-called hollow excavation; these excavators This is a model that can be used for trench excavation in the lower part _E2 where stabilizing liquid cannot be used.

In this embodiment, the depth h ₁ of the groove M ₁ in the upper layer E ₁ is approximately 10 m,
A construction example will be described in which the groove depth h ₂ of the lower layer E ₂ is approximately 30 m, but the present invention is not limited thereto.

First, use earth auger 1 to dig into stratum E ₁ to a depth of h _1.
Guide holes 3 and 4 are drilled while supplying stabilizing liquid Q (Figs. 1 and 2). Stabilizer Q usually contains clay minerals such as bentonite and attapulgite.
It is a slurry made by stirring and dissolving stabilizers such as CMC in water or seawater, and is used to prevent walls from collapsing during excavation.

When the guide holes 3 and 4 have been excavated, the part _E11 between the two guide holes is filled with the stabilizing liquid Q, and the upper groove _M1 is hollowed out using the club bucket 2 (Fig. 3). Complete (Figure 4).
When this groove M ₁ is completed, a casing 5 having a cross section that is almost the same as the oval cross section of this groove M ₁ is built into this groove 5 (Fig. 5), and a pump 6 is used to fill the inside of groove M ₁ , that is, the casing 5. muddy water (stabilizing liquid)
water is pumped up and removed (Figure 6). Note that the gap between the outer periphery of the casing 5 and the ground is filled with muddy water and solidified, or with low-strength mortar, sand, etc.
To prevent the groove wall surface from collapsing when the casing 5 is removed in a post-process.

Next, the diameter is slightly smaller than Earth Auger 1,
Guide holes 31, 41 are excavated from the bottom of the upper groove _M1 into the lower layer _E2 having cracks, etc., without using the stabilizing liquid Q, by means of an earth auger 11 that can be inserted into the casing 5. The depth of the guide hole at this time is a depth _h3 that penetrates the stratum _E2 and reaches the impermeable layer _E3 (Figs. 7 and 8). Next, the portion _E21 between the guide holes 31 and 41 is hollowed out using the club bucket 2 (FIG. 9) to complete the lower groove _M2 (FIG. 10). As a result, the upper groove M ₁ and the lower groove M ₂ form one deep groove M ₃ that is continuous in the vertical direction.

Next, at the side ends of this deep groove _M3 , an interlocking pipe 7 with a length reaching the groove bottom and a partition plate 8 with a depth _h1 that is close to this pipe 7 and partitions the groove _M1 in the vertical direction are installed. (Fig. 11), and then pour concrete C into the groove _M2 using a tremie pipe 9 (Fig. 12), filling it to a depth of _h2 and pouring it (Fig. 13). Therefore, the lower end of the partition plate 8 reaches the concrete C.

Next, when the concrete C has hardened, the interlocking pipe 7 is pulled out, and the water stop member 10 is installed near the top of the concrete C of the hole 42 defined in its place to block the hole 42, and the muddy water flows through the hole. 42 (Fig. 14). Water stop member 1
0, as shown in FIG. 18, consists of a closure bag 101 made of elasticity such as rubber, a disc 102 to which it is attached, and an injection tube 103 opening at the center of the disc.
Water, air, or the like is pressurized into the closed bag 101 so that it comes into pressure contact with the inner wall of the hole 42 to prevent muddy water from flowing in from above the disk 102. In addition, when water is to be stopped more strictly, the disc 10
2 Add some muddy water Q to the top and solidify it.
After that, the stabilizing liquid Q is poured into the space above the disk 102 in the hole 42.
and groove M ₁₁ on top of concrete C.
Backfill with sand S.

In this way, the preceding element (unit underground wall) is completed, and the upper portion 42a of the hole 42 is prepared as a guide hole for the upper groove for constructing the next element. That is, as shown in FIG. 16, the next guide hole 43 is drilled and the _E12 section is hollowed out to form the upper groove for the next element, and the guide holes 42, 42a are formed between the preceding element and the next element. It becomes the joint part with the element.

In addition, FIG. 19 shows another water-stopping member, in which a tapered screw is provided on the body, and water is stopped by screwing this body into the hole 42. There is.

〔Effect of the invention〕

As explained above, according to the present invention, the joint part is installed near the concrete top of the guide hole for the preceding element as a water-stopping member to prevent the stabilizing liquid from flowing into the lower layer. The advantage of this method is that a stabilizing liquid can be used to excavate strata that are prone to collapse, while excavation can be carried out without using a stabilizing liquid for strata that have cracks or the like and can cause water loss.

[Brief explanation of drawings]

Figures 1 to 16 are explanatory diagrams showing the embodiment of the present invention in the order of steps, in which figure a is a top view, figure b is a vertical cross-sectional view, and figure 17 is a cross-section of the ground for constructing an underground wall. Figures 18 and 19 are detailed views of the water stop member in Figures 14 to 16b. 3, 4, 31, 41, 42, 42a, 43...
Guide hole, 5...Casing, 7...Interlocking pipe, 10...Water stop member. _E1 , _E11
... Upper strata, E ₂ , E ₂₁ ... Lower strata,
_M1 , _M11 ...Top groove, _M2 ...Bottom groove, _M3 ...Deep groove, Q...Stabilizing liquid, C...Concrete.

Claims (1)

[Claims] 1. When constructing a continuous underground wall in a stratum that has a lower layer that cannot be used with a stabilizing liquid due to cracks in the upper layer that are prone to collapse, a stabilizing liquid is applied to the upper layer of the planned construction site of the underground wall. While preventing the wall from collapsing, a guide hole is excavated and a hollow is excavated to form the upper groove. After this groove is completed, a casing is built in the groove to pump up the stabilizing liquid. A lower groove is formed by drilling a guide hole and hollowing out the lower part of the lower part of the upper groove without using a stabilizing liquid, and an interlocking pipe is installed at the side end of the deep groove formed by this groove and the upper groove. After that, concrete is poured into the groove, and after the concrete has hardened, the interlocking pipe is pulled out.
Furthermore, a water stop member was installed near the concrete top of the guide hole where it was pulled out to prevent the stabilizing liquid from flowing into the lower layer, and then the stabilizing liquid was installed in the guide hole above the water stop member. A construction method for a joint part of a continuous underground wall, characterized by filling the joint and excavating an upper trench for the next element.