Method for constructing sheet pile

Abstract

To provide a construction method of a sheet pile capable of suppressing deformation of the sheet pile.SOLUTION: The construction method of the sheet pile includes a drilling process for drilling the ground, a sheet pile press-in process for pressing in the sheet pile 1 along a drilled part, and a filler injection process for injecting a filler B into a part where the ground is loosened by drilling. In the filler injection process, a steel pipe 21 in which an opening 22 opened downward is formed is inserted into a portion where the ground is loosened, and the filler B is supplied to the steel pipe 21. The lower end of the opening 22 is pointed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for installing sheet piles. [Background technology]

[0002] Conventionally, earth retaining walls have been constructed by installing steel sheet piles in the ground, as shown in the following Patent Document 1. Driving steel sheet piles using a sheet pile press-in machine such as a crush piler involves drilling holes with an auger, which disturbs the ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-100416 Summary of the Invention [Problem to be solved by the invention]

[0004] Drilling may cause the passive earth pressure strength to decrease below the design value, or the drilled area may become a water path, causing the acting water pressure to exceed the design lateral pressure, which may result in deformation of the steel sheet pile exceeding the design value.

[0005] Therefore, the present invention has been made in consideration of the above circumstances, and provides a sheet pile installation method that can suppress deformation of the sheet pile. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention employs the following means. That is, the sheet pile construction method according to the present invention includes a filler injection step of injecting filler into the portion of the ground that has been drilled and loosened.

[0007] In this construction method for sheet piles, filler is injected into the loose ground around the area where the sheet piles are placed. This hardens the ground around the area to a certain extent, thereby suppressing deformation and displacement of the sheet piles.

[0008] The sheet pile installation method according to the present invention may also include a hole drilling step of drilling holes in the ground, and a sheet pile pressing-in step of pressing sheet piles into the holes along the drilled portions.

[0009] In addition, in the sheet pile construction method of the present invention, in the filler injection process, a steel pipe having an opening that opens downward may be inserted into the part of the loosened ground, and the filler may be supplied to the steel pipe.

[0010] In this sheet pile construction method, a steel pipe with an opening that opens downward is inserted into the loosened part of the ground, and filler material is then injected. By inserting the steel pipe into the ground and positioning it at a predetermined depth, the filler material can be easily injected through the opening to the predetermined depth in the ground.

[0011] In the sheet pile installation method according to the present invention, the lower end of the opening may be pointed.

[0012] In the sheet pile installation method configured in this way, the lower end of the opening of the steel pipe is sharp, so that the steel pipe can be easily inserted into the ground.

[0013] In addition, in the sheet pile construction method of the present invention, the sheet pile may be formed in a U-shape that opens in one direction when viewed in a plane, and in the filler injection process, the filler may be injected into the open portion of the sheet pile.

[0014] In this construction method for sheet piles, the filler is injected into the section of the sheet pile that opens in one direction when viewed from above. This allows the filler to be injected into the ground without interfering with the steel pipe and the sheet pile. [Effects of the Invention]

[0015] According to the sheet pile installation method of the present invention, deformation of the sheet pile can be suppressed. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a sheet pile construction method according to one embodiment of the present invention. [Figure 2] FIG. 1 is a horizontal cross-sectional view showing a sheet pile construction method according to one embodiment of the present invention. [Figure 3] This is an analytical model diagram of Case 0 in the verification of a sheet pile construction method according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, a sheet pile construction method according to one embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a vertical cross-sectional view showing a sheet pile installation method according to one embodiment of the present invention, and Fig. 2 is a horizontal cross-sectional view showing a sheet pile installation method according to one embodiment of the present invention. As shown in Figures 1 and 2, the sheet pile construction method first involves the drilling process. A sheet pile press-in machine such as a crush piler is used to drill holes in the ground. As shown in Figure 2, holes are drilled with a screw or other tool at the location where the sheet pile 1 will be installed in a subsequent process. For example, in the case of sandy or clayey soil, it is possible to press the sheet pile in by drilling holes alone (core-punching), and the drilling range is shown by the two-dot chain line area A1. In the case of bedrock, sandy or clayey soil, holes are drilled first, and then the sheet pile is pressed in (pre-excavation-punching), and the pre-drilling range is shown by the two-dot chain line area A2, and the drilling range is shown by the two-dot chain line area A1.

[0018] Next, the sheet pile pressing process is carried out. Using a sheet pile pressing machine, the sheet pile 1 is inserted along the drilled portion. For example, in the case of sandy soil or clayey soil, the sheet pile 1 is pressed into the outside of the range A1. For example, in the case of bedrock, sandy soil, or clayey soil, the sheet pile 1 may be pressed into the area of ​​the range A2.

[0019] As shown in Figure 1, the sheet pile 1 has a shape that is long in the vertical direction. As shown in Figure 2, the sheet pile 1 is formed in a U-shape that opens in one direction in a plan view. The sheet pile 1 has a bottom 11, side wall portions 12, and an engaging portion 13. The bottom 11 is formed in a flat plate shape. The pair of side wall portions 12 extend from both ends of the bottom 11 in the width direction in a direction that intersects with the bottom 11. The engaging portion 13 is provided at the end of the side wall portion 12. The sheet pile 1 opens in the direction in which the side wall portions 12 extend relative to the bottom 1. Adjacent sheet piles 1 are arranged so that the opening sides in a plan view are staggered. The engaging portions 13 of adjacent sheet piles 1 are engaged with each other.

[0020] After drilling a hole in the ground to a predetermined depth with a screw, the screw may be pulled out and the sheet pile 1 may be pressed in, or the hole may be gradually drilled with the screw while the sheet pile 1 is gradually pressed in from behind.

[0021] Next, a filler injection step is carried out. The ground is loose in the areas A1 and A2 drilled in the drilling process. As shown in FIG. 1, an injection machine 2 is used, which has a steel pipe 21 attached to the tip of an injection hose (not shown). An opening 22 that opens downward is formed at the tip of the steel pipe 21. The lower end of the opening 22 is pointed. With the opening 22 of the steel pipe 21 facing downward, the steel pipe 21 is swung and inserted into the areas A1 and A2, and the steel pipe 21 is first inserted to the lower end of the sheet pile 1, and then the steel pipe 21 is gradually pulled up while injecting the filler material B. Cement bentonite, for example, can be used as the filler material B.

[0022] As shown in FIG. 2, a steel pipe 21 is placed in the area surrounded by the bottom 11 and the pair of side walls 12 of the sheet pile 1, in other words, the opening of the sheet pile 1, and a filler B is injected.

[0023] Next, the verification that was carried out will be described. The installation of the steel sheet pile (Sheet Pile 1) and the injection of filler material (Filler Material B) were completed. After the excavation in front of the steel sheet pile was completed, there was no ground deformation exceeding the design value, and the effectiveness of the above measures was confirmed.

[0024] In addition, an elastic-plastic analysis of the retaining wall was carried out for a model case with a self-standing height of 1.5 m, and the impact on the retaining wall displacement due to loosening of the ground caused by auger drilling and rising water levels was examined. The cases are as follows: Case 0: No loosening of the ground Case 1: Loosening of the ground Case 2: Ground loosening + rising water level The verification results are shown in Table 1.

[0025] [Table 1]

[0026] Case 1 resulted in a displacement approximately twice that of Case 0, and Case 2 resulted in a displacement approximately four times that of Case 0, confirming that loosening of the ground and rising water levels have a significant impact on the displacement of the retaining wall.

[0027] Based on the above, we believe that injecting filler into the loosened areas to ensure ground springs equivalent to or greater than those in Case 0 is an effective means of preventing the retaining wall from causing displacements that exceed the design value.

[0028] In the sheet pile construction method configured in this way, the filler B is injected into the loose ground around where the sheet pile 1 is placed. Therefore, the ground around where the sheet pile 1 is placed is hardened to a certain extent, so that deformation and displacement of the sheet pile 1 can be suppressed.

[0029] Furthermore, a steel pipe 21 having an opening 22 that opens downward is inserted into a portion of the loose ground, and filler B is injected. Therefore, by inserting the steel pipe 21 into the ground and locating it at a predetermined depth, filler B can be easily injected from the opening 22 of the steel pipe 21 to a predetermined depth in the ground.

[0030] Furthermore, the lower end of the opening 22 of the steel pipe 21 is sharpened, so that the steel pipe 21 can be easily inserted into the ground.

[0031] Moreover, the filler B is injected into a portion that opens in one direction in a plan view of the sheet pile 1. Therefore, the filler B can be injected into the ground without causing the steel pipe 21 to interfere with the sheet pile 1.

[0032] The shapes and combinations of the components shown in the above-described embodiment are merely examples, and various modifications can be made based on design requirements, etc., within the scope of the present invention.

[0033] For example, in the embodiment described above, the lower end of the opening 22 of the steel pipe 21 is pointed, but this is not limited to this. The tip of the steel pipe 21 may have a cross section cut in a direction perpendicular to the extending direction of the steel pipe 21, and the shape of the tip of the steel pipe 21 can be set appropriately. [Explanation of symbols]

[0034] 1 Yaita 21 Steel pipe 22 Opening A1,A2 range B Filler

Claims

1. A sheet pile construction method that includes a filler injection process in which filler is injected into areas where the ground has been loosened by drilling holes.

2. A drilling step of drilling the ground; The sheet pile installation method according to claim 1, further comprising a sheet pile pressing-in step of pressing a sheet pile along the drilled portion.

3. A sheet pile construction method as described in claim 1 or 2, wherein in the filler injection process, a steel pipe having an opening that opens downward is inserted into the part of the loose ground, and the filler is supplied to the steel pipe.

4. The sheet pile installation method according to claim 3, wherein the lower end of the opening is pointed.

5. The sheet pile is formed in a U-shape that opens in one direction in a plan view, The sheet pile construction method according to claim 2, wherein the filler is injected into an opening of the sheet pile in the filler injection step.

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