Method for measuring position of earth retaining anchor

Abstract

To provide a method for measuring a position of an earth retaining anchor, capable of accurately determining the position of the anchor.SOLUTION: An earth retaining anchor is embedded obliquely into the ground through a wall structure (parent pile 1 and cross sheet pile) of an earth retaining wall. In a method of measuring a position of an anchor, first, a walling bracket 5L, which supports a walling arranged horizontally to the wall structure from below, is fixed to each of the wall structures (a pair of parent piles 1), next, based on a design reference position A of the wall structure, an anchor ruler 10 is installed at a predetermined position of a pair of walling brackets 5L so as to span the pair of walling brackets 5L, the anchor ruler 10 having a reference surface 10p at its upper part, which corresponds to the inclination corresponding to the oblique angle of the anchor, and next, the reference surface 10p of the anchor ruler 10 installed on the pair of walling brackets 5L is used for measuring a penetration position C of the anchor on the wall structure.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for measuring the position of an earth retaining anchor. [Background technology]

[0002] An earth retaining wall, also called an earth retaining wall, is a temporary structure that uses wall structures such as sheet piles to prevent the surrounding ground from collapsing when excavating the ground. In particular, such wall structures are sometimes called earth retaining walls. When the surrounding area where the earth retaining wall is installed is on soft ground or when the excavation depth of the earth retaining wall is deep, ground anchors (hereinafter simply called anchors) are installed in the earth retaining wall to withstand the pressure of the ground (earth pressure). One type of earth retaining wall is a construction method in which H-shaped steel called parent piles are driven vertically at intervals and horizontal sheet piles are stacked between the flanges of adjacent parent piles to construct a wall structure. Patent Document 1 below discloses an earth retaining wall of this type.

[0003] When installing an anchor, a cross member called a waling is hung horizontally across the sides of multiple parent piles that are driven vertically. The waling is supported from below by brackets welded to the sides of the parent piles. Two parallel walings are usually provided. A base to which one end (head) of the anchor is attached is attached to a pair of walings at the center of adjacent parent piles. That is, the base is located in front of the cross sheet piles, and the anchor passes through the cross sheet piles and extends diagonally downward into the ground. The other end of the anchor is extended until it reaches the target ground, such as hard ground, and the anchor attached to the other end is fixed into the target ground. The anchor is installed with tension acting between the base and the anchor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-3364 A Summary of the Invention [Problem to be solved by the invention]

[0005] The anchor is inserted into an anchor hole that is drilled diagonally into the ground. At this time, a start hole is first drilled in the cross sheet pile, which is the starting position for drilling the anchor hole, and the ground is drilled diagonally from this start hole to form the anchor hole. Here, if the driving position of the parent pile is shifted toward the back or front of the ground to be supported, the position of the cross sheet pile will also shift toward the back or front of the ground due to the shift in the driving position of the parent pile. If the position of the start hole on the cross sheet pile is determined only by leveling the vertical height, the drilling start position of the anchor hole will shift toward the back or front of the ground. In this case, the position of the fixing body at the tip of the anchor hole drilled diagonally will not only shift toward the back or front, but also shift upward or downward.

[0006] For an anchor to function properly, it is important that the anchor body is securely fixed in the target ground. For this purpose, the position of the anchor hole, i.e., the position of the start hole where the drilling starts, must be determined accurately with respect to the ground, not with respect to the cross-sheet pile. The object of the present invention is to provide a method for measuring the position of an earth retaining anchor, which can accurately determine the position of the anchor. [Means for solving the problem]

[0007] In the position surveying method of the present invention, the position of the earth retaining anchor that penetrates the wall structure of the earth retaining wall and is buried obliquely into the ground is surveyed. In the position surveying method, (1) wale brackets that support the wale that is arranged horizontally to the wall structure from below are fixed to the wall structure, (2) an anchor ruler having a reference surface corresponding to the inclination corresponding to the oblique angle of the anchor at the top based on the design reference position of the wall structure is installed at a predetermined position of the pair of wale brackets so as to be spanned between the pair of wale brackets, and (3) the penetration position of the anchor on the wall structure is surveyed using the reference surface of the anchor ruler installed on the pair of wale brackets. Note that only a minimum configuration of a part of the entire configuration of the earth retaining wall is specified here. In reality, the entire earth retaining wall is configured by including a plurality of these minimum configurations. Effect of the Invention

[0008] According to the method for measuring the position of an earth retaining anchor of the present invention, the position of the anchor can be accurately determined. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a side view (partial cross-sectional view) showing the area around the head of the earth retaining anchor. [Diagram 2] FIG. 2 is a front view showing the periphery of the anchor head of the earth retaining structure. [Diagram 3] FIG. 2 is a schematic side view for explaining a position survey method for an earth retaining anchor according to an embodiment. [Figure 4] FIG. 2 is a perspective view for explaining the above method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A method for measuring the position of an earth retaining anchor according to an embodiment will be described below, but first, the configuration of the head portion of the earth retaining wall anchor and its surroundings will be described with reference to Figures 1 and 2. This configuration itself is a known configuration, so it will be described briefly.

[0011] FIG. 1 is a side view (partial cross-sectional view), and FIG. 2 is a front view. As shown in FIG. 1 and FIG. 2, multiple parent piles 1 are driven vertically into the ground at regular intervals. The parent piles 1 are H-shaped steel, and the parent piles 1 are aligned so that the web 1w connecting a pair of flanges 1f is parallel to the paper surface of FIG. 1. Wooden cross sheet piles 2 are stacked from bottom to top between adjacent parent piles 1. Both ends of each cross sheet pile 2 are engaged with the flange 1f of the H-shaped steel, which is the parent pile 1. As shown by dot hatching in FIG. 1, the backside of the parent piles 1 and the cross sheet piles 2 is filled with soil from the ground. Hereinafter, the main components of the earth retaining wall formed by the parent piles 1 and the cross sheet piles 2 will also be referred to as the wall structure.

[0012] Two wale-raising brackets 3U and 3L are horizontally installed on the side of the vertically driven parent piles 1, more specifically, on the surface of the flange 1f on the near side (left side in Fig. 1) with respect to the ground. Each wale-raising bracket 3U and 3L is also an H-shaped steel, and the orientation of each wale-raising bracket 3U and 3L is aligned so that the web 3w connecting the pair of flanges 3f is parallel to the horizontal plane. The upper wale-raising bracket 5U is supported from below by the upper wale-raising bracket 5U welded to the flange 1f of the parent pile 1 on both sides of the base 4 described later. The upper wale-raising bracket 5U is also an H-shaped steel. The lower wale-raising bracket 3L is also supported from below by the lower wale-raising bracket 5L welded to the flange 1f of the parent pile 1 on both sides of the base 4. The lower wale-raising bracket 5L is formed by welding an L-shaped angle material. The wale-raising brackets 5U and 5L are installed at a predetermined vertical height based on the design reference positions of the wale-raising brackets 3U and 3L.

[0013] Between the flanges 3f of each of the wales 3U, 3L and the flange 1f of the parent pile 1, backfilling material 6 is provided to fill the gap. In addition, stiffeners 7 are filled on the webs 3w of each of the wales 3U, 3L for reinforcement. The stiffeners 7 may be formed by pouring concrete, or may be formed by welding a steel plate to the pair of flanges 3f and web 3w so as to be perpendicular to the pair of flanges 3f and web 3w. Providing the stiffeners 7 prevents the flanges 3f from buckling due to the load input to each of the wales 3U, 3L via the anchors 8 and base 4 described below.

[0014] A pedestal 4 is attached to the center of two adjacent parent piles 1. It is not necessary to provide a pedestal 4 between all adjacent parent piles 1, that is, it is not necessary to provide a pedestal 4 for every vertical row of cross sheet piles 2. For example, one pedestal 4 is attached to every three vertical rows of cross sheet piles 2. The pedestal 4 is composed of a pair of side plates 4s, three connecting plates 4m welded between the side plates 4s, and a sheet plate 4p that serves as a seat for the head of the anchor 8. The sheet plate 4p is not welded to the pair of side plates 4s in order to adjust the position of the anchor 8, but may be welded to the pair of side plates 4s after the installation of the anchor 8 is completed.

[0015] When the anchor 8 is installed so that tension is applied, the upper part of the base 4 is pressed against the upper wale 3U, and the lower part of the base 4 is pressed against the lower wale 3L. To prevent the base 4 from falling during installation and removal, a hook 4f is formed on each side plate 4s so that the base 4 can be hooked onto the flange 3f of the lower wale 3L.

[0016] An anchor cap 8h is attached to the head of the anchor 8, and this anchor cap 8h is pressed against the sheet plate 4p of the base 4 by the tension acting on the anchor 8. The anchor 8 is installed to extend diagonally downward through the cross sheet pile 2 into the ground. Although not shown, an anchor is attached to the tip of the anchor 8, and the anchor reaches the ground to be fixed. In this way, a retaining wall is constructed by the wall structure (parent pile 1 and cross sheet pile 2), walings 3U, 3L, anchor 8 and associated waling brackets 5U and 5L, base 4, etc.

[0017] The anchors 8 are installed using the above-described structure, but prior to this, anchor holes into which the anchors 8 are inserted are drilled in the ground. When drilling the anchor holes, it is first necessary to open start point holes 9 (see FIG. 2) in the cross sheet pile 2, which are the starting points for drilling the holes. The surveying method of this embodiment relates to surveying the positions of the start point holes 9. The surveying method of this embodiment will be described below with reference to FIGS. 3 and 4.

[0018] An example will be described in which the positions of the parent piles 1 on both sides where the anchors 8 are installed, i.e., the positions of the wall structures, are shifted 200 mm to the right in FIG. 3 (to the rear in FIG. 2) from the design reference position. Here, the vertical height of the center of the start point hole 9 formed in the horizontal sheet pile 2 when the parent pile 1 is driven into the design reference position is X mm. However, since the position of the parent pile 1 is shifted 200 mm to the rear, the position of the horizontal sheet pile 2 is also shifted 200 mm to the rear. For this reason, if the horizontal sheet pile 2 shifted to the rear is simply leveled to form the start point hole 9 at a vertical height of X mm and the anchor hole is drilled diagonally downward, the anchor hole, i.e., the anchor 8, will be shifted upward from the design position as shown in FIG. The surveying method according to this embodiment can prevent such shifts and is also excellent in workability.

[0019] In this embodiment, an anchor ruler 10 is used to assist in surveying. The anchor ruler 10 is a frame-shaped jig on whose upper part a reference surface 10p is formed that is inclined at an angle corresponding to the extension angle of the anchor 8. The anchor ruler 10 of this embodiment is composed of a pair of side frames 10s, a pair of rails 10r that connect the inclined upper sides of the side frames 10s, and a ruler stick 10q that is operated by the operator when surveying the position of the start hole 9.

[0020] The side frame 10s is formed by welding L-shaped angle bars. The rail 10r and the ruler bar 10q are cut from wooden square bars. The side frame 10s and the rail 10r can be fixed to each other with a C-clamp or the like when the anchor ruler 10 is in use. The spacing between the parent piles 1 can vary depending on the site, so the rail 10r can be cut out accordingly. Configuring the anchor ruler 10 in this way increases its versatility. Also, if the anchor ruler 10 is dismantled after use, the storage space can be reduced. How to use the anchor ruler will be explained later.

[0021] The position of the starting hole 9 is measured before the lower wale 3L is installed on the lower wale bracket 5L. First, the design reference position of the parent pile 1 (wall structure) is marked on the upper surface of the lower wale bracket 5L to which the anchor ruler 10 described above will be fixed (see part A in Figure 3). Here, the design reference position of the parent pile 1 is the surface of the flange 1f on the front side of the parent pile 1. If all the parent piles 1 are shifted toward the back side (right side in Figure 3), the design reference position of the parent pile 1 can be marked at once on all the lower wale brackets 5L lined up at the same height using a water line, which is efficient. If there is a parent pile 1 that is shifted toward the front side (left side in Figure 3), the design reference position can be marked at once on both sides using water lines.

[0022] Next, a position 100 mm forward from the above-mentioned design reference position (part A) is marked on the top surface of the lower wale-raising bracket 5L. This position becomes the installation reference position for the anchor ruler 10. The parent pile 1 is driven near the design reference position, even if there is some misalignment. For this reason, taking into consideration the securing of working space, the installation reference position for the anchor ruler 10 is measured so that the anchor ruler 10 is installed 100 mm away from the design reference position. Note that this dimension does not have to be 100 mm. Furthermore, this dimension of 100 mm makes it easy to deal with parent piles 1 that are misaligned toward the front (left side in Figure 3).

[0023] The center position of the pair of parent piles 1 is also surveyed. At this center position, a vertical center line L is marked on the cross sheet pile 2 (see Figure 4). The anchor ruler 10 is fixed onto the lower wale raising bracket 5L so that the front lower end of the side frame 10s of the anchor ruler 10 coincides with the installation reference position surveyed based on the design reference position (part A) of the parent pile 1. The anchor ruler 10 can be fixed by fixing the side frame 10s to the lower wale raising bracket 5L with a C-clamp or the like. In this way, the anchor ruler 10 can be easily removed.

[0024] Here, the upper side of the side frame 10s of the anchor ruler 10 forms a reference plane 10p inclined to match the inclination of the anchor 8. The matching rail 10r is attached to the upper side of the side frame 10s, so that the lower surface of the matching rail 10r matches the reference plane 10p. As described above, the anchor ruler 10 is installed 100 mm away from the design reference position (part A) of the parent pile 1, so the height of the anchor ruler 10 is determined taking into account this distance of 100 mm. That is, the height of the side frame 10s is determined in advance so that the reference plane 10p passes through the design reference position (part B in FIG. 3) of the center of the start hole 9 at the design reference position (part A) 100 mm away, and the anchor ruler 10 is formed.

[0025] Therefore, the ruler rod 10q of the anchor ruler 10 is brought into contact with the underside of the pair of rails 10r to find the intersection with the vertical center line L marked on the cross-sheet pile 2 (see part C in FIG. 3). This is equivalent to finding the intersection of the inclined reference plane 10p and the vertical center line L, and this intersection is the center position of the start hole 9 to be formed on the cross-sheet pile 2. At this time, the ruler rod 10q is for visualizing the reference plane 10p, and it is sufficient that it is in contact with the underside of the pair of rails 10r, and it does not have to be used so as to be parallel to the paper surface of FIG. 3, and the operation is very simple. The start hole 9 is formed in the cross-sheet pile 2 with the surveyed part C as the center. If an anchor hole is drilled diagonally from the formed start hole 9 and the anchor 8 is installed, the anchor 8 is installed in the design reference position.

[0026] Since the anchor 8 is supported by a pair of wales 3U and 3L via the base 4, the positional relationship between the anchor 8 and the corresponding lower wale 3L is constant. Therefore, the positional relationship between the lower wale bracket 5L supporting the lower wale 3L and the start hole 9 is also constant. Therefore, the survey of the start hole 9 described above can be performed for other anchors 8 at the same site in the same way. At this time, the positional deviation of the parent pile 1 may vary for each one, but the survey of the design reference position and the marking on the lower wale bracket 5L can be performed at once using a water line as described above. Also, even if the deviation amount of the parent piles 1 on both sides for surveying the center of the start hole 9 is different, the same procedure can be performed using the anchor ruler 10 after the survey of the design reference position and marking. Many anchors 8 are installed in the earth retaining structure at a certain site, and the positions of the start holes 9 for all of these many anchors 8 can be surveyed efficiently using the surveying method of the present embodiment described above.

[0027] According to the surveying method of this embodiment, the position of the anchor 8 that penetrates the cross sheet pile 2 provided between a pair of vertically driven parent piles 1 and is buried diagonally into the ground is surveyed in the following steps (1) to (3). More specifically, the position of the start hole 9 for the anchor 8 is surveyed. (1) The lower wale bracket 5L that supports the lower wale 3L arranged perpendicularly to the pair of parent piles 1 from below is fixed to the pair of parent piles 1. (2) Based on the design reference position of the pair of parent piles 1, the anchor ruler 10 is installed at a predetermined position of the pair of wale brackets 5L so as to span the pair of lower wale brackets 5L. The anchor ruler 10 has a reference surface 10p at its upper part that corresponds to the inclination corresponding to the diagonal angle of the anchor 8. (3) The reference surface 10p of the anchor ruler 10 installed on the pair of lower wale brackets 5L is used to survey the penetration position of the anchor 8 on the cross sheet pile 2 (i.e., the center position of the start hole 9).

[0028] Therefore, even if the parent pile 1 is misaligned, the penetration position of the anchor 8 with respect to the lower wale-raising bracket 5L (the center position of the start hole 9) can be determined taking into account the misalignment. Since the penetration position of the anchor 8 (the center position of the start hole 9), i.e., the position of the anchor 8, is accurately determined with respect to the ground taking into account the misalignment of the parent pile 1, the anchor 8 can be accurately installed in its design reference position. Here, the amount of misalignment of the parent pile 1 corresponding to each installation location of the anchor 8 may differ, but since the anchor ruler 10 is used, it is not necessary to perform on-site position calculation work for each installation location of the anchor 8, and work efficiency can be improved. In addition, many anchors 8 are installed in an earth retaining structure, and the same procedure can be used to survey all of the anchors 8, which also improves work efficiency.

[0029] Here, in the above (2), it is preferable to carry out the steps of (2-1) and (2-2) below. (2-1) Mark the design reference position of the parent pile 1 on the lower wale-raising bracket 5L (see part A in Fig. 3). (2-2) Install the anchor ruler 10 at a predetermined position of the lower wale-raising bracket 5L based on the marked design reference position of the parent pile 1. In this way, the anchor ruler 10 can be efficiently installed on the lower wale-raising bracket 5L fixed to the parent pile 1, taking into account the amount of positional deviation of the parent pile 1. In addition, many lower wale-raising brackets 5L are installed in the earth retaining structure, and the above work (2-1) can be performed at once for lower wale-raising brackets 5L of the same height using a water line, which also improves work efficiency.

[0030] The present invention is not limited to the above-described embodiment, and the components can be modified and embodied in the implementation stage without departing from the spirit of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment.

[0031] For example, in the above embodiment, the rail 10r is a wooden block and fixed to the side frame 10s with a C-shaped clamp. However, the rail 10r may also be made of an L-shaped angle bar and welded to the side frame 10s to form the anchor ruler 10. Also, in the above embodiment, the pair of rails 10r are attached to the upper side of the side frame 10s, but they may be attached to the side frame 10s so as to be flush with the upper side of the side frame 10s. In this case, the reference plane 10p is defined by the upper side of the side frame 10s and the upper surface of the rail 10r, so the ruler bar 10q can be used by placing it on the pair of rails 10r.

[0032] Furthermore, in the above embodiment, the pair of side frames 10s are connected by a pair of rails 10r. However, after the pair of side frames 10s are fixed to the lower wale-raising bracket 5L by a C-clamp or the like, the inclined upper sides of the side frames 10s may be connected by a string to form the reference surface 10p. Also, the ruler bar 10q in the above embodiment is a square timber, but it may be a thin round bar that does not bend.

[0033] In the above embodiment and the above-mentioned earth retaining wall disclosed in Patent Document 1, the wall structure of the earth retaining wall is formed by a pair of vertically driven parent piles 1 and a horizontal sheet pile 2 stacked vertically between the pair of parent piles 1. A pair of wale brackets 5U, 5L are fixed to the pair of parent piles 1, respectively. However, the present invention can also be applied to an earth retaining wall in which a wall structure is formed by a plurality of vertical sheet piles arranged horizontally and driven vertically. In this case, a pair of wale brackets only needs to be fixed to a pair of vertical sheet piles among the plurality of vertical sheet piles, and the start hole 9 is formed in another vertical sheet pile located between the pair of vertical sheet piles. When a wall structure is formed by a plurality of vertical sheet piles, steel sheet piles or steel pipe sheet piles can be used as the vertical sheet piles.

[0034] Furthermore, in the above embodiment, the base 4 is attached between the pair of wales 3U, 3L. However, if a wall structure is formed using steel vertical sheet piles, only the lower wale 3U may be provided and the base 4 may be installed so as to rest on this lower wale 3U, and the upper part of the base 4 may be directly pressed against the vertical sheet pile in which the start point holes 9 are formed. That is, in this case, the base 4 is attached to only one wale 3U. The present invention can also be applied to such a form of earth retaining structure.

[0035] In the above embodiment, the installation position of the anchor ruler 10 is fixed at a position 100 mm away from part A in FIG. 3, which is the design reference position of the parent pile 1 (earth retaining wall), and the height of the side frame 10s is determined in advance in consideration of this installation position, and the anchor ruler 10 is manufactured. However, the installation position of the anchor ruler 10 may not be fixed, and the anchor ruler 10 may be installed according to the design reference position of the earth retaining wall, and surveying may be performed. In this case, it is not necessary to determine the height of the side frame 10s in advance according to the installation position of the anchor ruler 10 and manufacture the anchor ruler 10. A specific example of the surveying procedure in this case will be briefly described. The procedure is performed according to the above embodiment until the anchor ruler 10 is installed on the pair of lower wale-raising brackets 5L. Then, the ruler bar 10q is used to fix the anchor ruler 10 on the pair of lower wale-raising brackets 5L so that the reference surface 10p inclined at an angle according to the extension angle of the anchor 8 passes through the design reference position (part B in FIG. 3) of the center of the start hole 9. Then, the ruler rod 10q is used to find the intersection between the reference plane 10p and the vertical center line L on the cross sheet pile 2 (wall structure), and this intersection becomes the center position of the start hole 9 (part C in Figure 3). [Explanation of symbols]

[0036] 1 Main pile (wall structure) 2 Horizontal sheet pile (wall structure) 3U,3L Stomach stand 5U,5L Belly Raising Bracket 8. Anchor 9 Starting hole (Penetration position of anchor 8 on the wall structure) 10 Anchor Ruler 10p reference plane A (Wall structure on lower wale bracket 5L) Design reference position C. Penetration position (penetration position of anchor 8 on wall structure)

Claims

1. A method for measuring the position of an earth retaining anchor that penetrates a wall structure of an earth retaining wall and is embedded obliquely into the ground, comprising the steps of: A pair of wale-raising brackets are fixed to the wall structure, the wale-raising brackets supporting the wale-raising members from below the wall structure, the wale-raising brackets being disposed horizontally relative to the wall structure; Based on the design reference position of the wall structure, an anchor ruler having a reference surface at the top corresponding to the inclination corresponding to the oblique angle of the anchor is installed at a predetermined position of the pair of the wale-raising brackets so as to span the pair of the wale-raising brackets; A method for measuring the position of a retaining anchor, comprising measuring the penetration position of the anchor on the wall structure using the reference surface of the anchor ruler installed on a pair of the wale-raising brackets.

2. When the wale-raising bracket is installed in the predetermined position, the design reference position of the wall structure is marked on the wale-raising bracket; 2. The method for measuring the position of an earth retaining anchor according to claim 1, further comprising the step of installing the anchor ruler at the predetermined position of the wale-raising bracket based on the marked design reference position of the wall structure.

3. The wall structure includes a pair of vertically driven parent piles and a cross sheet pile stacked vertically between the pair of parent piles, 3. The method for measuring the position of an earth retaining anchor according to claim 1, wherein the pair of wale-raising brackets are fixed to the pair of parent piles, respectively.

4. The wall structure includes a plurality of vertical sheet piles arranged horizontally and vertically driven in, 3. The method for measuring the position of an earth retaining anchor according to claim 1, wherein the pair of wale-raising brackets are fixed to a pair of vertical sheet piles among the plurality of vertical sheet piles, respectively.

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