JP2005127092A - Work-execution method for anchor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To work-execute an anchor with a core material without disturbing or loosening a ground. <P>SOLUTION: This work-execution method for the anchor comprises a rod press-fitting step for press-fitting a hollow rod 1 fitted with a bit 2 at its tip in the ground 5 to a specified depth along a horizontal or diagonal direction while rotating, a core material insert step for inserting the core material 6 into the rod 1 and reaching the tip part thereof to the bit 2, and a rod extraction step for extracting the rod 1 from the ground while discharging a solidifying material liquid 7 from the tip of the rod 1 in the state of the core material 6 and the bit 2 leaving in the ground 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for constructing an anchor made of a columnar solid body in which a core material is present on the ground, and more preferably, a core material for a railway or road embankment whose surface is covered with a concrete retaining wall. The present invention relates to a method for constructing a bar-shaped anchor having

  As conventional construction of a rod-shaped anchor having a core material, Patent Literature 1 and Patent Literature 2 disclose that construction is performed while water is ejected from the tip of a bit to the ground. Patent Document 3 discloses that the construction is performed while air (compressed air) is ejected from the tip of the bit.

Patent Document 4 discloses the use of a screw-type earth anchor without using water or air, although it is not a method of constructing a rod-shaped anchor having a core material. Patent Document 5 and Patent Document 6 disclose a method of constructing anchors on a cut surface covered with concrete or the like.
Japanese Patent Publication No. 7-33665 Japanese Patent No. 2698762 JP 2002-213173 A Japanese Patent Laid-Open No. 5-239829 Japanese Patent Publication No. 5-22775 Japanese Patent No. 2829489

  In conventional anchor construction, since water or air (compressed air) is used during drilling, there is a problem in that the surrounding ground is disturbed and loosened by water or air ejected from the tip of the bit. In addition, most of the water and air that was used during excavation and served as an excavation aid is discharged to the surface from the periphery of the anchor, and the excavated soil is also discharged to the surface. Need to treat the soil. In such a method, since the surrounding ground is loosened, if there is little earth covering between the anchor such as a rod-shaped anchor to be built and the road surface or the railroad track surface, the ground subsidence phenomenon is likely to occur, and the road or railroad May cause troubles in use. In addition, the solidified material liquid such as cement milk to be injected may flow into the surrounding ground loosened during drilling.

  On the other hand, when it is necessary to eliminate the cavity between the ground and the concrete surface covered with sprayed concrete or the like, the method described in Patent Document 5 penetrates the surface of the concrete and makes a hole in the ground. After being evacuated, an anchor is inserted into this hole, and grout is press-fitted into the inserted anchor to fill the cavity. In this way, the anchor is inserted into the hole that has been evacuated in advance, so that the grout is discharged into the loose surrounding ground. For the anchor used in such a case, a bit having an excavation capability is not used.

  Also, as in Patent Document 6, when anchors are provided inside the continuous wall, the anchors are provided inside the continuous wall using holes provided in the continuous wall, and the anchors are provided. The drilling water is used to inject cement milk as a solidifying material. Therefore, also in this method, in addition to disturbing and loosening the surrounding ground by the water and air ejected from the tip, the cement milk also flows into the loosened surrounding ground.

  As described above, both methods are based on the premise that the surrounding ground is disturbed and loosened.If there is little soil covering between the rod-shaped anchor and the road surface or railroad track surface, the ground subsidence phenomenon will occur. It is easy to cause, and there is a risk that it may interfere with use as a road or railway.

  On the other hand, the method using the screw-type earth anchor described in Patent Document 4 does not disturb the natural ground, but it is necessary to bury the anchor itself provided with the spiral projection blades. And if the screw type anchor has a small diameter, it is necessary to drive a large number of anchors in order to stabilize the slope, etc., while the enforcement takes a long time, while in the case of a large diameter, in order to stabilize the slope etc. The number of anchors required is reduced, but the anchors themselves are expensive.

  The present invention has been made in consideration of the above-described conventional problems, and can implement a rod-shaped anchor without disturbing or loosening the ground. Moreover, the anchor and the road surface or the railway track surface can be used. An object of the present invention is to provide an anchor construction method that can be constructed without causing any trouble in traffic on roads and railways in use even when there is little earth covering.

  In order to achieve the above object, the anchor construction method of the invention of claim 1 press-fits the ground to a predetermined depth along a horizontal direction or an oblique direction while rotating a hollow rod having a bit attached to the tip. The rod press-in process, the core material insertion process in which the core material is inserted into the rod and the tip reaches the bit, and the solidified material liquid is discharged from the tip of the rod with the core material and the bit left in the ground. And a rod extracting step of extracting the rod from the ground.

  In the invention of claim 1, by rotating the rod, the bit attached to the tip of the rod advances in the ground while compacting the ground, and the rod is press-fitted into the ground. Therefore, excavation can be performed without using water or compressed air, and ground disturbance and loosening caused by these can be eliminated.

  After the rod is press-fitted, the solidified material liquid is solidified with the bit and the core material remaining in the ground by pulling the rod out of the ground while protruding the solidified material liquid with the core material inserted. Thereby, construction of the rod-shaped anchor provided with the peripheral frictional force can be performed.

  The anchor construction method according to the second aspect of the present invention is such that a core material is inserted into a hollow rod having a bit attached to the tip so that the tip reaches the bit, and in this state, the rod is rotated horizontally or obliquely. A rod press-in step for press-fitting into the ground to a predetermined depth along the direction, and a rod pull-out step for pulling out the rod from the ground while discharging the solidified material liquid from the tip of the rod while leaving the core material and the bit in the ground. It is characterized by having.

  In the invention of claim 2, the core material is press-fitted into the ground with the core material inserted into the rod, and in addition to having the same action as in claim 1, there is no core material insertion step. Easy to install.

  A third aspect of the present invention is the anchor construction method according to the first or second aspect, wherein the rod press-fitting step performs press-fitting while striking the rod in addition to rotation.

  By hitting in this way, the rod can be pressed into the ground more smoothly and quickly.

  The invention of claim 4 is the anchor construction method according to claim 1 or 2, wherein, prior to the rod press-fitting step, a window hole is drilled by a bit in a retaining wall covering the ground surface, and the window The rod is press-fitted into the ground through a hole.

  In invention of Claim 4, even if the retaining wall which consists of concrete etc. has covered the ground surface, an anchor can be constructed reliably.

  A fifth aspect of the invention is the anchor construction method according to the first or second aspect, wherein the outer diameter of the bit is larger than the outer diameter of the rod.

  Since the rod has a smaller diameter than the bit as described above, the friction between the rod and the ground is reduced, so that the press-fitting can be performed smoothly.

  A sixth aspect of the present invention is the anchor construction method according to the first or second aspect, wherein a concave portion into which the leading end portion of the core member is fitted is formed at a substantially central portion of the back surface of the bit. .

  By forming the recess in the bit in this way, the core material is supported by the recess, so that the core material can be reliably held at the substantially central portion of the rod.

  According to the present invention, the rod is press-fitted with a bit attached to the tip of the rear surface of an existing wall, for example, a relatively loose portion such as a slope or cut surface of a railway or road embankment. Since it is press-fitted without using water or air, the ground is squeezed firmly without loosening the ground, and the collapse of the hole wall can be prevented. In addition to this, since the ground around the hole wall is crumpled by honey, the flow of solidifying material liquid such as cement milk to be injected is reduced, and an anchor having a peripheral frictional force can be obtained. As a result, even when there is little earth covering between the anchor and the road surface or the railroad track surface, the subsidence phenomenon does not occur, and the occurrence of trouble even on the road or railroad in use is extremely reduced.

  In addition, since it is not necessary to use water or air when excavating, excavated soil associated with water or air is eliminated, and excavated soil discharged becomes extremely small, so that no soil removal treatment is required.

  Furthermore, since the rod used for press-fitting is recovered, it does not become expensive like the screw-type anchor method in which everything is buried. In addition, since it is not necessary to use a double pipe structure that uses an outer pipe to prevent collapse when drilling with an inner pipe using water, etc., the construction is simplified and the construction cost can be reduced. It becomes possible.

  Fig.1 (a)-(g) shows the construction process in one embodiment of this invention. The construction to the ground 5 is to press-fit the rod 1 along the oblique direction or the horizontal direction with respect to the slope 5 a of the ground 5.

  The rod 1 has a hollow shape, and a bit 2 is attached to the tip thereof. At the time of construction on the ground 5, an excavator 3 such as a rotary percussion drill is used to press-fit the ground 5 while rotating the rod 1. At the time of press fitting, the excavator 3 is supported by the slope 4.

  As shown in FIGS. 1 (a) to 1 (c), the excavator 3 is moved on the slope 4 and the rod 1 is rotated to give a propulsive force to the bit 2 and press the rod 1 into the ground 5. To do. In this press-fitting, excavation by the rotating bit 2 is performed, so that the rod 1 can be advanced without using water or air (compressed air).

  FIG. 2 shows the structure of the rod 1 and the bit 2. As the rod 1, a hollow single tube rod having a single-walled portion is used. The bit 2 is detachable by being fitted to the tip of the rod 1.

  In this embodiment, the outer diameter D1 of the rod 1 is somewhat smaller than the maximum outer diameter D2 of the excavation part 2a in the bit 2. Thus, by making the outer diameter D1 of the rod 1 smaller than the outer diameter D2 of the bit 2, the friction of the rod peripheral surface against the ground is reduced during the rotation excavation. For this reason, energy required for excavation can be reduced, the excavation speed can be increased, and efficient press-fitting can be performed. In addition, a concave portion 2b into which a core material 6 to be described later is inserted is formed at a substantially central portion on the back surface of the bit 2.

  The bit 2 is made of steel. The bit 2 may be a cross bit or a button bit, and any bit can be used as long as it has a shape capable of excavation.

  FIG. 3 shows a case in which a cross bit is used as the bit 2, and a cemented carbide chip 21 made of a cemented carbide or the like is provided in the same plane in a cross shape at the tip of the bit body 20. FIG. 4 shows another example of the cross bit, in which a cross-shaped cemented carbide tip 21 is inclined at the tip of the bit body 20.

  FIG. 5 shows a case where a button bit is used as the bit 2, and a large number of block-shaped cemented carbide chips 21 are embedded at the tip of the bit body 20, thereby enabling excavation.

  In this embodiment, the digging is performed while rotating the bit 2 together with the rod 1, and water or air is not ejected from the bit 2 at the tip of the rod 1. For this reason, the ground on the side surface of the bit 2 is not disturbed, and the ground can be thickened on the rotating side surface because the soil is in the no-draining state. That is, the excavation is performed while the surrounding ground is honeyed in the soil-free state, and the rod 1 plays a role of collapsing the surrounding ground thus compacted into the excavated portion.

  FIG. 1 (d) shows a state in which the rod 1 has reached a predetermined depth. In this state, the core material 6 is inserted into the rod 1 from the rear end portion of the rod 1 as indicated by an arrow A. This insertion is performed until the tip of the core material 6 reaches the bit 2 as shown in FIG. As described above, the recess 2 b is formed on the back surface of the bit 2, and the core 6 is held at a substantially central portion inside the rod 1 by fitting the tip of the core 6 into the recess 2 b. The In addition, as the core material 6, what twisted the steel wire, the steel rod, the thing made from a thick synthetic resin, and what hardened fibers, such as a synthetic fiber and glass fiber, with the resin may be sufficient.

  FIG. 1 (f) shows a process after the insertion of the core material 6, and the rod 1 is moved in the direction indicated by the arrow B while a solidifying material liquid 7 made of a grout material such as cement milk is injected from the tip portion of the rod 1. Pull out. At the time of this drawing, the bit 2 and the core material 6 are left inside the ground 5, and the hole excavated by the bit 2 is filled with the solidifying material liquid 7 around the core material 6.

  FIG. 1 (g) shows a state in which the solidifying material liquid 7 is solidified after the rod 1 is collected. By solidifying the solidifying material liquid 7, a rod-shaped anchor 8 in which the core material 6 is fixed to a substantially central portion of the solidifying material is formed. In the anchor 8 in which the solidified material liquid 7 is solidified, the core material 6 acts to give the anchor 8 strength against bending shear. Thereby, it can be set as the anchor 8 which can prevent collapse of embankment.

  In excavation, the surrounding ground is not disturbed during excavation, but is consolidated in the reverse direction so that the surrounding ground is compacted and prevented from collapsing. The solidified material liquid 7 such as the grout material is less likely to deviate to the surrounding ground, resulting in a rod-shaped anchor 8 having a circumferential frictional force.

  In such construction, since the rod-shaped anchor 8 is resistant to bending shear due to the presence of the core material 6 and a peripheral frictional force can be expected, the diameter of the anchor 8, that is, the excavation diameter by the bit 2 should be 50 mm or more. However, in order to shorten the rod-shaped anchor 8 and increase the peripheral frictional force, the diameter is preferably 100 mm or more. In this case, although it may exceed 170 mm, it is preferable to be 170 mm or less because the energy required for excavation increases.

  Conditions such as the diameter and length of the rod-shaped anchor 8 described above, the required number, and the thickness of the core material 6 to be used are changed according to the conditions of the slope and the cut surface that require construction. be able to. For example, when the diameter of the rod-shaped anchor 8 is small, the anchor 8 is lengthened or a large number of anchors 8 are constructed. When the diameter is large, the anchor 8 is shortened or a small number of anchors 8 is constructed. be able to. As described above, the anchor 8 has a diameter, a length, and a number of used placements that are changed according to the ground conditions. Therefore, the length of the anchor 8 cannot be limited, but the rod-shaped anchor 8 constructed according to this embodiment is Since peripheral frictional force is expected, about 5 m is sufficient, and about 10 m is sufficient depending on the ground condition.

  FIGS. 6A to 6E show the construction in another embodiment of the present invention in the order of steps. In this embodiment, the core material 6 is inserted into the rod 1 prior to the excavation of the rod 1. That is, as shown in FIG. 6A, the core material 6 is inserted into the rod 1 so that the tip reaches the bit 2. The tip of the inserted core member 6 is fitted and held in a recess 2b (see FIG. 2) formed in the bit 2.

  6A to 6C show the excavation of the rod 1, and the excavator 3 such as a rotary percussion drill excavates the slope 5 a of the ground 5 while rotating to the rod 1 and the bit 2. Even in this case, it press-fits into the ground 5 without using water or air.

  When the rod 1 reaches a predetermined depth, as shown in FIG. 6 (d), the rod 1 is pulled out from the ground 5 while injecting a solidified material liquid 7 made of a grout material such as cement milk. At this time, the bit 2 and the core material 6 are left in the ground 5, and the solidified material liquid 7 is filled in the hole excavated by the bit 2 around the core material 6. Then, when the rod 1 is recovered and the solidified material liquid 7 having the core material in the center is solidified, the rod-shaped anchor 8 having the core material 6 is obtained as shown in FIG.

  Thus, when the core material 6 is inserted into the rod 1 from the beginning, the anchor 8 having the core material 6 is used as compared with the case where the core material 6 is inserted later in the state of being inserted into the ground 5. The construction process can be shortened, and the time until the anchor 8 is obtained is shortened. For this reason, it becomes a preferable construction method.

  In the above embodiment, the rod-shaped anchor having the core member 6 is constructed with respect to the slope, but the present invention can also be applied to the case of constructing on a vertical cut surface.

  To reinforce existing embankment where railways and roads are already open, if the excavation is carried out by ejecting water or air from the bit while the upper surface of the anchor is close to the roadbed surface (so-called soil covering is small), The road surface may swell due to pressure, or the hole may be collapsed due to collapse of the hole, which may cause the road surface to be disturbed and affect traffic. On the other hand, in these embodiments, since water and air are not ejected from the bit 2, the ground on the side surface of the bit 2 is not disturbed, and it is possible to make a soil-free state. Consolidate. For this reason, it is suitable for reinforcement of the embankment surface where the railway and the road are already open.

  It should be noted that the slope or cut surface of the embankment or the like where the railroad or road is already open has a retaining wall (concrete retaining wall) 15 reinforced with concrete as shown in FIG. Many. In this case, the back surface of the retaining wall 15 is loosely packed with a backfilling material 16 such as general gravel or slag. Furthermore, there are many cobblestones, boulders, concrete shells 17 and the like in the embankment, and the embankment has a relatively loose ground. In such a case, when a hole (not shown) is made in the retaining wall 15 using a concrete core collecting device and an anchor is provided through the window hole by a conventional method, a backfill material 16 or a cobblestone 17 exists. Therefore, the water and air spouted from the bit are more likely to rebound in the vertical direction, and the roadbed surface bulge phenomenon and depression phenomenon are likely to occur.

  On the other hand, in the present invention, the anchor 8 can be applied to the ground having the retaining wall 15 by the above-described process. That is, railways and roads have already been opened on embankments, etc., and there are retaining walls 15, and there are backfill materials 16 such as gravel and mine, and further cobbles, boulders, concrete shells 17, etc. in the embankments. In the case of construction on a slope or cut surface when there is a relatively loose ground, the rod 1 is used with water and air with the bit 2 attached to the tip of the hollow rod 1 This is possible by opening a window hole in the retaining wall 15 while rotating without rotating, and press-fitting the rod 1 to a predetermined depth while rotating without using water or air.

  In order to construct through the retaining wall 15 in this way, the bit 2 is provided with a cemented carbide tip 21 such as cemented carbide in a cross shape on the same plane as shown in FIG. As shown in FIG. 4, a cross-shaped cemented carbide tip 21 such as a cemented carbide alloy provided in an inclined shape is used. Further, as shown in FIG. 5, even a button bit in which a large number of cemented carbide chips 21 such as cemented carbide are embedded at the tip thereof can be applied through the retaining wall 15. By penetrating the retaining wall 15 made of concrete or the like in this way, it is possible to easily penetrate the backfilling material 16, cobbles, rolling stones, concrete shells 17, etc. existing in the embankment.

  In order to penetrate the retaining wall 15, the diameter of the bit 2 (that is, the excavation diameter) is preferably as small as possible. On the other hand, in order to increase the peripheral frictional force of the anchor 8, the diameter of the bit 2 is preferably as large as possible. For this reason, in order to penetrate the retaining wall 15 and construct the anchor 8 to a desired depth, the diameter of the bit 2 (that is, the excavation diameter) is preferably about 50 mm to 130 mm. If the diameter is too large, a large amount of energy is required for penetrating the retaining wall 15, and it takes too much drilling time. If the diameter is too small, the diameter of the anchor 8 obtained becomes small, and its peripheral area becomes small. It will be too small.

  Even in such a case, conditions such as the diameter and length of the rod-shaped anchor 8, the required number, and the thickness of the core material 6 to be used are the conditions of the slope and the cut surface that require construction. Will be changed according to That is, when the diameter of the anchor 8 is small, it is necessary to lengthen the anchor 8 or to construct a large number of anchors 8. When the diameter is large, the anchor 8 is shortened or a small number of anchors is constructed.

  The shape of the bit 2 shown in FIGS. 3 to 5 described above can also be used when constructing a slope or a cut surface where the retaining wall 15 made of concrete or the like does not exist. By using the bit 2 having such a shape, all or a part of foreign matters such as cobblestones, boulders and concrete shells scattered in the embankment can be crushed. At the same time, crushed pieces or foreign substances that could not be crushed can be pushed in the circumferential direction of the rod 1 or pushed forward.

  In the construction shown in FIGS. 1 and 6, a rotary percussion drill capable of giving a hit while rotating the rod 1 is used. Thus, by giving a blow while rotating the rod 1, the excavation speed can be increased, so that the construction time can be shortened and a window hole can be easily formed in the retaining wall 15. Not limited to this, depending on the conditions of the ground, a device that pushes the rod 1 while rotating, for example, a device provided with means for pushing the rotating device without hitting the rotating device while gripping and rotating the rod by the rotating device. May be used.

  Next, it will be described with reference to FIGS. 8 to 10 that the rod-shaped anchor 8 of the present invention can expect a circumferential frictional force. 8 to 10, a rod is a rod having a bit attached to a tip that is press-fitted while being rotated when inserted into the ground (a rod that is pulled up with the tip bit remaining when being pulled up). 8 to 10, it is assumed that the bit diameter and the rod diameter are the same. Moreover, the horizontal axis in FIGS. 8 to 10 is indicated by a multiple of the radius of the rod. 8 to 10 are graphs showing the results of theoretical soil mechanics analysis.

  FIG. 8 shows that the force pressing the ground is transmitted to the surrounding ground by pushing the rod into the ground without using water or air from the viewpoint of the gap ratio of the ground. The gap ratio indicates the ratio of voids existing in the ground having a constant volume, and the amount of voids decreases when the ground is compressed. By being compressed in this way, the gap ratio changes.

  In FIG. 8, the ratio between the gap ratio e0 of the original ground and the gap ratio e of the ground when the rod is pushed into the ground without using water or air is taken as the vertical axis, and from the inserted rod peripheral surface. The value obtained by dividing the circumferential distance by the rod radius is shown on the horizontal axis. In FIG. 8, as a result of the decrease in the gap ratio in the ground in the portion in contact with the rod peripheral surface (ie, the result of consolidation), the value of the gap ratio e of the ground when the rod is pushed into the gap ratio e0 of the original ground is the largest. Although the level of decrease is gradually reduced, it indicates that the ground is compressed to a position separated by a distance corresponding to the diameter of the rod.

  When the gap ratio changes in this way, the ground is compacted, and as a result, the ground deformation coefficient E changes. That is, when the rod is pushed into the ground without using water or air, the deformation coefficient E0 of the original ground becomes the deformation coefficient E of the ground due to the insertion of the rod. In the ground engineering, the ratio of the strain applied to the ground and the strain generated in the ground when stress is applied to the ground is used as the deformation coefficient. As in the present invention, stress is generated by inserting the rod, the ground is distorted, and the deformation coefficient is changed.

  FIG. 9 shows the ratio of the deformation coefficient E0 and the deformation coefficient E as the vertical axis, and the value obtained by dividing the circumferential distance from the inserted rod peripheral surface by the rod radius as the horizontal axis as in FIG. . From FIG. 9, the ratio of the deformation coefficient in the ground in the portion in contact with the rod peripheral surface is the highest, the ratio of the deformation coefficient is high even at the distance to the radius of the rod, and even if the distance corresponding to the diameter of the rod is separated, It shows a high deformation coefficient. Thus, by pushing the rod into the ground without using water or air, the force pressing the ground is transmitted to the surrounding ground. And the shear strength of a surrounding ground also improves by changing the deformation coefficient of a ground in this way.

  FIG. 10 is a graph showing the ground shear strength. That is, since the ground is consolidated, the shear strength is increased. Therefore, when the rod is pushed into the ground without using water or air, the shear strength of the surrounding ground is increased. In FIG. 10, the ratio between the shear strength τ0 of the original ground and the shear strength τ of the ground when the rod is pushed into the ground without using water or air is taken as the vertical axis, and the distance from the circumferential surface of the inserted rod The value obtained by dividing the circumferential distance by the rod radius is the horizontal axis as in FIG. Also in FIG. 10, the shearing force in the ground in the portion in contact with the rod peripheral surface is the highest, and although it gradually decreases, the shearing force increases to a position separated by a distance corresponding to the diameter of the rod.

  In any of the cases shown in FIGS. 8 to 10, the ground is compressed to a position separated by a distance corresponding to the rod diameter, although the ground is compressed most gradually and gradually decreases in the ground in contact with the rod peripheral surface. It shows that.

  Further, in FIGS. 8 to 10, the values when the rod is pulled up as shown in FIGS. 1 (f) and 6 (e) are indicated by broken lines. The value when the rod shown by the broken line is pulled up is slightly lower than that when the rod is inserted as shown by the solid line, but still shows a high value. Thus, since the value when the rod shown by the broken line is pulled up shows a high value, even when the rod diameter is slightly smaller than the diameter of the tip bit, it is almost the same as when the rod shown by the broken line is pulled up. It is natural to show similar values.

  As described above, in the construction method of the present invention, the ground is compressed to the position where the distance corresponding to the diameter of the rod is separated, although the ground is the highest compressed and gradually decreases in the ground contacting the rod peripheral surface. (Ie modified). And the rod-shaped anchor 8 having the core material constructed according to the present invention has its surrounding ground integrally reinforced with a wide range of modified ground, and therefore expects a high circumferential frictional force. be able to. Even when the rod-shaped anchor 8 is short, an excellent reinforcing effect can be exhibited for the above reason.

  Thus, since the bar-shaped anchor obtained by the present invention is a bar-shaped anchor that can be expected to have a frictional force on the circumferential surface, it is an embankment in which a retaining wall such as concrete or masonry exists, or an embankment in which there is no retaining wall. Even if cobblestones, rolling stones, concrete shells, etc. are dispersed, if the ground is relatively loose compared to the case where it is hard and consolidated, that is, relatively loose ground, the surrounding ground will be tightened during construction of the present invention. It can be hardened.

  From the above, the above-mentioned embankment is a preferable ground as the ground that can maximize the effects of the present invention. On the contrary, as described above, in a relatively loose embankment, that is, a relatively loose embankment (for example, the ground illustrated in FIG. 7), when water or compressed air is used as in the conventional construction method, the roadbed surface is It becomes difficult to apply because it is disturbed.

  Further, since the anchor 8 obtained by the present invention can be expected to have a frictional force on the peripheral surface, the anchor 8 may be constructed with a shallower construction depth than that of the ground anchor. The process can be shortened.

  Thus, the present invention is a construction method having many advantages, and is a construction method particularly suitable for relatively loose embankment, that is, relatively loose embankment. In addition to this, the present invention is not limited to a relatively loose embankment, but can also be applied to a tighter ground, as is apparent from the ability to drill holes in retaining walls such as concrete.

It is sectional drawing which shows the construction method in one embodiment of this invention. It is sectional drawing of the rod which provided the bit. It is a front view of an example of a bit. It is the front view and side view which show the other example of a bit. It is the front view and side view which show other example of a bit. It is sectional drawing which shows the construction method in another embodiment of this invention. It is sectional drawing applied to the slope which has a retaining wall. It is a graph which shows the change of the gap ratio number of the ground by the construction method of the present invention. It is a graph which shows the change of the deformation coefficient of the ground by the construction method of the present invention. It is a graph which shows the change of the shear strength of the ground by the construction method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rod 2 Bit 3 Excavator 5 Ground 6 Core material 7 Solidification material liquid 8 Anchor

Claims (6)

A rod press-fitting step of press-fitting into the ground to a predetermined depth along a horizontal direction or an oblique direction while rotating a hollow rod with a bit attached to the tip;
A core material insertion step in which the core material is inserted into the rod and the tip reaches the bit;
An anchor construction method comprising: a rod drawing step of drawing a rod from the ground while discharging the solidified material liquid from the tip of the rod while leaving the core material and the bit in the ground. Insert a core material into a hollow rod with a bit attached to the tip and let the tip reach the bit. In this state, press the rod into the ground to a predetermined depth along the horizontal or diagonal direction while rotating the rod. Rod press-fitting process;
An anchor construction method comprising: a rod drawing step of drawing a rod from the ground while discharging the solidified material liquid from the tip of the rod while leaving the core material and the bit in the ground.   3. The anchor construction method according to claim 1 or 2, wherein the rod press-fitting step performs press-fitting while striking the rod in addition to rotation.   The anchor according to claim 1 or 2, wherein, prior to the rod press-fitting step, a window hole is drilled by the bit into a retaining wall covering the ground surface, and the rod is press-fitted into the ground through the window hole. Construction method.   The anchor construction method according to claim 1 or 2, wherein an outer diameter of the bit is larger than an outer diameter of the rod.   The anchor construction method according to claim 1 or 2, wherein a concave portion into which the tip of the core member is fitted is formed at a substantially central portion on the back surface of the bit.

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