Underground wall construction method and underground wall

Abstract

To shorten a construction period as compared with the case of constructing an underground wall having an impervious wall and an earth retaining wall by using an earth auger.SOLUTION: A construction method of an underground wall includes an impervious wall construction step of constructing an impervious wall by inserting one drilling section into the ground and injecting cement slurry into in-situ soil while moving in one direction in a state in which the one drilling section is inserted into the ground and widening a portion mixed with the in-situ soil, an earth retaining wall construction step of constructing an earth retaining wall having a thickness thicker than a thickness of the impervious wall by injecting the cement slurry into the in-situ soil while moving in one direction in a state in which the other drilling section wider than the one drilling section is inserted into the ground and widening a portion mixed with the in-situ soil, and a core material erection step of sequentially erecting core materials in the earth retaining wall.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a method for constructing a diaphragm wall and to a diaphragm wall. [Background technology]

[0002] Patent Document 1 describes a method for constructing a water cut-off wall, which involves constructing a water cut-off wall in an underground water-retaining layer, and then constructing a water cut-off wall to prevent the collapse of the excavated area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-184036 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, a watertight wall that is narrower than the earth retaining wall is sometimes constructed below the earth retaining wall. In such cases, the watertight wall is constructed by drilling holes in the ground using multiple earth augers, and after the watertight wall is constructed, the earth retaining wall is constructed by drilling holes to the middle of the watertight wall using multiple earth augers with a larger outer diameter. In this construction method, the earth augers are repeatedly inserted and removed from the ground to expand the underground wall horizontally.

[0005] The object of the present disclosure is to shorten the construction period compared to when an underground wall having a water barrier wall and an earth retaining wall is constructed using an earth auger. [Means for solving the problem]

[0006] The method for constructing an underground wall according to the first aspect is characterized by comprising: a water-shielding wall construction step of inserting one hole-drilling section into the ground and, while moving the first hole-drilling section in one direction while it is inserted into the ground, injecting cement slurry into the in-situ soil to widen the portion to be mixed with the in-situ soil, thereby constructing a water-shielding wall; a retaining wall construction step of inserting another hole-drilling section that is wider than the first hole-drilling section into the ground up to the middle of the water-shielding wall, and, while moving the other hole-drilling section in the same direction while it is inserted into the ground, injecting cement slurry into the in-situ soil to widen the portion to be mixed with the in-situ soil, thereby constructing an earth-retaining wall that is thicker than the thickness of the water-shielding wall; and a core material erection step of sequentially erecting core materials into the earth-retaining wall.

[0007] According to the above aspect, one hole-making unit is inserted into the ground and moved in one direction while injecting cement slurry to widen the area to be mixed with the in-situ soil, thereby constructing a watertight wall. Furthermore, another hole-making unit is inserted into the ground and moved in one direction while injecting cement slurry to widen the area to be mixed with the in-situ soil, thereby constructing an earth retaining wall that is thicker than the watertight wall. This shortens the construction period compared to constructing an underground wall that includes a watertight wall and an earth retaining wall using an earth auger.

[0008] The underground wall construction method according to the second aspect is the underground wall construction method according to the first aspect, characterized in that in the earth retaining wall construction step, one side of the earth retaining wall is constructed so as to be aligned with one side of the watertight wall.

[0009] According to the above-described embodiment, one face of the retaining wall is constructed so as to be flush with one face of the water impermeable wall. This allows a common guide wall to be used when moving one drilling section in one direction and when moving another drilling section in the same direction, without having to move the guide wall that guides the drilling section.

[0010] The underground wall according to the third aspect is characterized by comprising a waterproof wall of uniform thickness and a retaining wall constructed above the waterproof wall, the thickness of which is greater than that of the waterproof wall and which also has a uniform thickness.

[0011] According to the above aspect, the underground wall has a water impermeable wall with a uniform thickness and an earth retaining wall with a uniform thickness. In other words, the underground wall is provided with a water impermeable wall that has no steps in the thickness direction and an earth retaining wall that has no steps in the thickness direction. This makes it possible to suppress variations in strength in the thickness direction from part to part, compared to an underground wall that has steps in the thickness direction. [Effects of the Invention]

[0012] According to the present disclosure, construction time can be shortened compared to when an underground wall having a water barrier wall and an earth retaining wall is constructed using an earth auger. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are schematic diagrams showing a construction machine used in a method for constructing an underground wall according to an embodiment of the present disclosure. [Figure 2] 1A and 1B are schematic diagrams showing a construction machine used in a method for constructing an underground wall according to an embodiment of the present disclosure. [Figure 3] 1 is a diagram illustrating a method of constructing a diaphragm wall according to an embodiment of the present disclosure. [Figure 4] 1A and 1B are diagrams showing a water barrier wall and an earth retaining wall constructed by a method for constructing an underground wall according to an embodiment of the present disclosure. [Figure 5] 1A and 1B are diagrams showing a water barrier wall and an earth retaining wall constructed by a method for constructing an underground wall according to an embodiment of the present disclosure. [Figure 6] 1A and 1B are perspective views showing an underground wall according to an embodiment of the present disclosure and an underground wall according to a comparative embodiment. [Figure 7] 1A and 1B are diagrams illustrating an underground wall according to a variation of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] An example of a method for constructing a diaphragm wall and a diaphragm wall according to an embodiment of the present disclosure will be described with reference to Figures 1 to 7. Note that arrow H shown in each figure indicates the up-down direction, i.e., the vertical direction, arrow W shown in each figure indicates the width direction perpendicular to arrow H and also the horizontal direction, and arrow D shown in each figure indicates the depth direction perpendicular to arrows H and W and also the horizontal direction.

[0015] (Construction equipment used to build underground walls) Two continuous trench excavators 20, 30 and a crane 40 are used to construct the underground wall.

[0016] The continuous trench excavator 20 is used in a soil cement diaphragm wall construction method (the so-called "TRD construction method"), and as shown in Figures 1(A) and 1(B), it comprises a crawler 22, a hole-drilling unit 24 having a cutter post 24a and a chain cutter 24b, and a main body 26 to which the upper end of the hole-drilling unit 24 is connected. The vertical length of the hole-drilling unit 24 is L1 (see Figure 1(A)), and the depth thickness of the hole-drilling unit 24 is T1 (see Figure 1(B)). The hole-drilling unit 24 is an example of one hole-drilling unit.

[0017] The continuous trench excavator 30 is used in a soil cement diaphragm wall construction method (the so-called "TRD construction method"), and as shown in Figures 2(A) and 2(B), is equipped with a crawler 32, a hole-making unit 34 having a cutter post 34a and a chain cutter 34b, and a main body 36 to which the upper end of the hole-making unit 34 is connected. The hole-making unit 34 is an example of another hole-making unit.

[0018] The vertical length of hole-making portion 34 is L2 (see FIG. 2(A)), and the depthwise thickness of hole-making portion 34 is T2 (see FIG. 2(B)). Here, length L2 of hole-making portion 34 is shorter than length L1 of hole-making portion 24, and thickness T2 of hole-making portion 34 is thicker than thickness T1 of hole-making portion 24.

[0019] Furthermore, the crane 40 has a gripping portion 42 (see FIG. 3) that grips the end of the H-beam 16.

[0020] (Construction method of underground walls) Next, a method for constructing the underground wall 10 will be described.

[0021] First, with the chain cutter 24b moving around the outer periphery of the cutter post 24a of the continuous trench excavator 20 shown in Figure 1, the main body 26 of the continuous trench excavator 20 is moved from above to below, and the hole-making part 24 attached to the main body 26 is inserted into the ground from the ground GL, as shown in Figures 1(A) and (B). If the length of the hole-making part 24 is long, the hole-making part 24 is divided longitudinally and inserted into the ground in multiple installments while adding sections of the hole-making part.

[0022] Once the hole-drilling unit 24 is inserted into the ground, as shown in FIG. 3, the chain cutter 24b is rotated in the ground, moving the hole-drilling unit 24 from one side in the width direction (the right side in the figure) to the other side in the width direction. As the hole-drilling unit 24 moves, cement slurry is injected into the in-situ soil from the tip of the cutter post 24a. The injected cement slurry is then mixed with the in-situ soil while excavating in the direction of movement, and a soil-cement impermeable wall 12 is constructed as shown in FIG. 4(A) (impermeable wall construction process). In other words, the soil-cement impermeable wall 12 is constructed by the TRD method. The width direction is an example of one direction.

[0023] Next, with the chain cutter 34b moving around along the outer periphery of the cutter post 34a of the continuous trench excavator 30 shown in Figure 2, the main body 36 of the continuous trench excavator 30 is moved from above to below, and the hole-drilling unit 34 attached to the main body 36 is inserted from the ground GL into the ground, as shown in Figures 2(A) and (B). Specifically, as shown in Figure 3, the hole-drilling unit 34 is inserted from the ground GL into the ground up to the middle part of the water impermeable wall 12 constructed by the continuous trench excavator 20. If the length of the hole-drilling unit 34 is long, the hole-drilling unit 34 is divided longitudinally and inserted into the ground in multiple installments while adding sections of the hole-drilling unit.

[0024] Once the hole-drilling unit 34 is inserted into the ground, as shown in Figure 3, the chain cutter 34b is rotated underground, moving the hole-drilling unit 34 from one widthwise side (the right side in the figure) to the other widthwise side. As the hole-drilling unit 34 moves, cement slurry is injected into the in-situ soil from the tip of the cutter post 34a. The injected cement slurry is then mixed with the in-situ soil while excavating in the direction of movement, constructing a retaining wall 14 that is wider than the impermeable wall 12, as shown in Figure 4(B) (retaining wall construction process). In other words, the soil-cement retaining wall 14 is constructed using the TRD method.

[0025] Here, the lower end of the impermeable wall 12 in the up-down direction (vertical direction) is located below the lower end of the earth retaining wall 14. In other words, the earth retaining wall 14 is constructed above the impermeable wall 12. The impermeable wall 12 constructed by the TRD method has a uniform thickness without any steps in the thickness direction, while the earth retaining wall 14 is thicker than the impermeable wall 12 and has a uniform thickness without any steps in the thickness direction.

[0026] Next, as shown in Fig. 3, the end of the H-shaped steel 16 is grasped by the grasping part 42 of the crane 40, and the crane 40 sequentially erects the H-shaped steel 16 into the retaining wall 14 (core material erection process). This increases the rigidity of the retaining wall 14, as shown in Fig. 5(A). The H-shaped steel 16 is an example of a core material.

[0027] Through these steps, the underground wall 10 is constructed. Then, as shown in Fig. 5(B), the ground GL is excavated to a required height, and the series of steps is completed.

[0028] (summary) As explained above, in the method for constructing the underground wall 10, the soil cement impermeable wall 12 is constructed by the TRD method, and then the soil cement retaining wall 14 is constructed by the TRD method. This shortens the construction period compared to when an underground wall having a impermeable wall and an earth retaining wall is constructed using an earth auger.

[0029] In addition, in the construction method of the underground wall 10, a soil cement impermeable wall 12 is constructed using the TRD method, and then a soil cement retaining wall 14 is constructed using the TRD method. This reduces the amount of cement used compared to constructing an underground wall with a waterproof wall and an earth retaining wall using an earth auger, which reduces construction costs and the environmental impact. In addition, by constructing a thin wall with low resistance in advance, the yield rate is improved.

[0030] Furthermore, in a comparative underground wall 110 constructed using a bucket-type boring machine or an earth drill machine, steps occur in the thickness direction, as shown in Fig. 6(B). On the other hand, the underground wall 10 according to this embodiment, as shown in Fig. 6(A), has a watertight wall 12 that is uniform in thickness and has no steps in the thickness direction, and an earth retaining wall 14 constructed above the watertight wall 12, which is thicker than the watertight wall 12 and has a uniform thickness and no steps in the thickness direction. In other words, the underground wall 10 has a watertight wall 12 that has no steps, and an earth retaining wall 14 that has no steps. This makes it possible to suppress variations in strength in the thickness direction from one part to another, compared to an underground wall that has steps in the thickness direction.

[0031] While the present disclosure has been described in detail with respect to a specific embodiment, it will be apparent to those skilled in the art that the present disclosure is not limited to such an embodiment and that various other embodiments are possible within the scope of the present disclosure. For example, in the above embodiment, the center line of the water shield wall 12 in the thickness direction and the center line of the earth retaining wall 14 in the thickness direction overlap. However, the earth retaining wall 14 may be constructed so that one side of the water shield wall 12 and one side of the earth retaining wall 14 are aligned. Here, Figures 7(A) and (B) show underground walls 60 and 70 according to variations of this embodiment. In the underground walls 60 and 70, the earth retaining wall 14 is constructed so that one side of the water shield wall 12 and one side of the earth retaining wall 14 are aligned. In this way, by constructing the retaining wall 14 so that one side of the water shielding wall 12 and one side of the retaining wall 14 are aligned, a common guide wall that guides the drilling sections 24, 34 can be used when excavating the water shielding wall 12 and when excavating the retaining wall 14 without having to move the guide wall.

[0032] In addition, in the above embodiment, the H-shaped steel 16 is used as the core material of the retaining wall 14, but other steel materials may also be used.

[0033] Furthermore, although not specifically explained in the above embodiment, after the hole-making sections 24, 34 are inserted into the ground, cement slurry is injected to construct the water-impermeable wall 12 or the retaining wall 14, but before the cement slurry is injected to construct the water-impermeable wall 12 or the retaining wall 14, an excavation step may be provided in which the chain cutters 24b, 34b are rotated and the hole-making sections 24, 34 are moved in the width direction to loosen the ground. [Explanation of symbols]

[0034] 10 underground wall 12 Impermeable wall 14 Retaining wall 16 H-beam (example of core material) 20 Continuous trench excavator 24 Drilling section (example of one drilling section) 30 Continuous trench excavator 34 Drilling section (an example of another drilling section) 60 underground wall 70. Earthly Wall

Claims

1. a water impermeable wall construction process in which one hole drilling part is inserted into the ground, and the one hole drilling part is moved in one direction while being inserted into the ground, and cement slurry is injected into the in-situ soil to expand the area to be mixed with the in-situ soil, thereby constructing a water impermeable wall; a retaining wall construction process in which another drilling section, which is wider than the first drilling section, is inserted into the ground up to a middle portion of the water impermeable wall, and while the other drilling section is inserted into the ground and moved in the same direction, cement slurry is injected into the in-situ soil to widen the portion to be mixed with the in-situ soil, thereby constructing an earth retaining wall whose thickness is thicker than the thickness of the water impermeable wall; a core material erection process of sequentially erecting core materials into the retaining wall; A method for constructing a diaphragm wall comprising:

2. In the earth retaining wall construction step, one surface of the earth retaining wall is constructed so as to be aligned with one surface of the water impermeable wall. A method for constructing a diaphragm wall according to claim 1.

3. A watertight wall with a uniform thickness; a retaining wall constructed above the impermeable wall, the thickness of which is thicker than the thickness of the impermeable wall and has a uniform thickness; An underground wall comprising:

Images