JP4716134B2 - Slope stabilization method - Google Patents

Description

  The present invention relates to a stabilization method for stabilizing slopes such as embankment slopes and cut slopes.

  The slope stabilization method includes inserting a reinforcing bar into the hole drilled in the ground, and injecting hardened material grout to fix the reinforcing bar to the ground, and drilling in the ground using a casing Conventionally, there has been known a ground anchor method in which an anchor is inserted into a casing, the casing is pulled out, and then a hardening material grout is injected into a hole to fix the anchor to the ground.

  However, according to the above reinforcing bar reinforced earth method, in addition to using a small diameter (about 20 to 30 mm) reinforcing bar, both the drilling diameter and the drilling length are considerably small (drilling diameter: about 40 to 60 mm, drilling length: 5 m). Degree), the thickness of the grout fixing layer is also small, and the resistance to tension, bending, shearing, etc. cannot be expected so much, and there is a problem that it is limited to a small-scale slope stabilization measure. In addition, according to the above ground anchor method, the tensile strength is sufficient, but the resistance to bending and shear cannot be expected, and in addition, a large prestress is imparted to the anchor, so that the bearing plate has high rigidity and large size. Legal frames and cross blocks are required, and it takes a lot of man-hours and time to place them.

  Therefore, development of a slope stabilization method that replaces the above-mentioned reinforcing steel reinforcement method and ground anchor method has been promoted recently. For example, in Patent Document 1, after a steel pipe with a check valve having a small diameter of 100 to 300 mm is inserted into the ground, the check valve is opened from the inside of the steel pipe, and a hardening material is formed in the ground around the steel pipe. A method of fixing the steel pipe by pressurizing grout is disclosed. Further, in Patent Document 2, a rotating member (spiral rotating blade) is provided at the tip, and a reinforcing material (steel pipe) provided with an injection port for a stable treatment material (hardening material grout) is stabilized from the injection port. A construction method is disclosed in which an anchor is formed by rotating and pressing into the ground while jetting a material to form a columnar stabilization treatment layer (fixing layer) around the reinforcing material. According to these construction methods, the steel pipe is integrated with the surrounding fixing layer and exerts a great resistance to pulling, bending, shearing, etc., and thus greatly contributes to the stabilization of the slope.

  By the way, the slope collapse often occurs when the underground moving layer (main active area) is loosened by groundwater such as seepage water or spring water, and the tendency is particularly prominent on the embankment slope. In addition, the slope collapse caused by this groundwater is not a sufficient measure even by the above-mentioned new construction method. Therefore, it is necessary to construct a drainage work separately when reinforcing slopes with a lot of groundwater, especially embankment slopes. As a result, extension of the construction period and increase in construction cost are unavoidable.

  For example, in Patent Document 3, a reinforcing column body is constructed by digging while discharging the consolidated material from the tip of the auger into the ground, and a hollow core material having a water collecting hole at the tip is inserted into the reinforcing column body. And the slope reinforcement construction method which makes the front-end | tip part protrude in the ground, and drains through a core material is described. However, according to this construction method, since the impervious reinforcing pillars are arranged around the hollow core material, water is drained only from the front end side of the reinforcing pillars, and as a countermeasure against the collapse of the slope caused by the groundwater, It is insufficient.

JP 2002-275907 A JP 2004-162417 A JP-A-7-189264

  The present invention has been made in view of the above-described technical background, and the problem is that it is sufficient to secure the yield strength against tension, bending, shearing, etc., and as a countermeasure against slope collapse caused by groundwater. Is to provide a sufficient slope stabilization method.

In order to solve the above-mentioned problems, the present invention provides a steel pipe with a small diameter check valve provided with a spiral rotor blade at least at the tip and rear ends, and a small diameter perforated steel pipe that functions as a drain pipe The steel pipe with check valve is inserted into the ground layer while the steel pipe with check valve is inserted into the underground immovable layer by rotating and press-fitting both steel pipes into the ground while adding the holed steel pipe to the steel pipe with check valve. It is located in the moving layer above the immovable layer, and then the check valve is opened from the inside of the steel pipe with the check valve to inject the hardened material grout into the ground around the steel pipe, and the reverse A spiral rotor blade provided at the rear end of a steel pipe with a check valve is used as a shielding plate for suppressing the flow of the hardened material grout to the moving layer side, and the steel pipe with a check valve is fixed to the non- moving layer. And

In the slope stabilization method performed in this way, the steel pipe with a check valve penetrates to the fixed layer, and the steel pipe is fixed to the fixed layer by injecting the hardened material grout around it. Demonstrates great strength against shear. In addition, since a perforated steel pipe having a drain function is positioned in the moving layer where loosening is likely to occur due to the groundwater, groundwater is drained to the outside through the perforated steel pipe, and the moving layer is not loosened due to the influence of groundwater.
Moreover, by providing a spiral rotary blade at the rear end of the steel pipe with check valve or at the front end of the perforated steel pipe, the rotary blade is used as a shielding plate for suppressing the flow of the hardened material grout to the moving layer side. Since the hardened material grout is prevented from entering around the perforated steel pipe, the drain function of the perforated steel pipe is not impaired.

In this invention, it replaces with the spiral rotary blade of the rear-end part of the steel pipe with a non-return valve, or the front-end | tip part of the said perforated steel pipe, or the cup which connects the said steel pipe with a non-return valve and the said perforated steel pipe It is good also as providing a spiral rotary blade in a ring. Also in this case, since the rotating blade is used as a shielding plate for suppressing the flow of the hardened material grout to the moving layer side, the hardened material grout can be prevented from entering around the perforated steel pipe. The drain function is not impaired.

  In the present invention, it is desirable to use a steel pipe with a check valve and a perforated steel pipe having a small diameter of 100 mm or less. This is because the embankment slope is generally present in a narrow environment and enables construction by a small construction machine. However, if the diameter is too small, bending strength and shear strength are insufficient, so it is desirable that the diameter be 70 mm at the smallest.

  In the present invention, a spiral rotary blade may be provided at the rear end portion of the perforated steel pipe, and the rotary blade may be used as a bearing plate for pressing the surface of the slope. In this case, a process of providing a separate bearing plate becomes unnecessary, so that the construction cost is reduced.

  According to the slope stabilization method according to the present invention, it is not only sufficient to ensure the proof strength against tension, bending, shearing, etc., but also as a countermeasure against slope collapse due to groundwater, especially slopes with a lot of groundwater, especially embankment slopes. It will be extremely useful for reinforcement of steel.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows the state of the slope after the stabilization method according to the present invention is implemented. The present embodiment is intended for the embankment slope 1, and shows a plurality of deterring piles 10 placed in the ground from the slope 2 of the embankment slope 1. The embankment slope 1 has a slip surface A behind the slope surface 2, a side deeper than the slip surface A is a non-moving layer (fixing region) B, and a side of the slope surface 2 from the slip surface A is a moving layer (main working). Region) C. Each deterrent pile 10 is placed sufficiently deeper than the sliding surface A in a state inclined by a predetermined angle θ (θ = 0 to 30 degrees) with respect to the horizontal axis L.

  As shown also in FIG. 2 and FIG. 3, each deterrent pile 10 has the same wall as the steel pipe 12 with a check valve in which a large number of check valves 11 are provided on the pipe wall in the circumferential direction and the axial direction. A hollow pile body 16 in which a perforated steel pipe 14 having a large number of openings 13 provided in the circumferential direction and in the axial direction is connected via a coupling 15, and a check valve constituting the hollow pile body 16 It consists of a grout fixing layer 17 formed around the steel pipe 12. The hollow pile body 16 is driven into the ground so that the boundary portion (coupling 15) between the steel pipe 12 with check valve and the perforated steel pipe 14 is located almost on the slip surface A, and thereby has a check valve. The entire steel pipe 12 is disposed in the floating layer B, and the entire perforated steel pipe 14 is disposed in the moving layer C. In this embodiment, as the steel pipe 12 with a check valve and the perforated steel pipe 14, a small diameter steel pipe having a diameter of 70 to 100 mm is used. Moreover, as the steel pipe 12 with a reverse valve, the steel pipe with a node which has many nodes 18 in the axial direction is used.

  Here, the opening 13 of the perforated steel pipe 14 is an elongated rectangular hole. As an example, the opening 13 has a width of about 1 to 3 mm and a length of about 14 mm. This prevents entry of earth and sand from the opening 13 into the steel pipe 14, but allows water to enter. It has become so. That is, the perforated steel pipe 14 functions as a drain pipe.

  In the present embodiment, the steel pipe 12 with a check valve is provided with spiral rotor blades 19A and 19B at two positions, that is, the front end and the rear end, while the perforated steel pipe 14 has a rear end. A similar spiral rotor blade 19C is provided. Each of the rotor blades 19A to 19C is set to have a size that is sufficiently larger than the outer diameter of the steel pipes 12 and 14 (as an example, 1.5 to 3.0 times the steel pipe diameter). . Moreover, the spiral direction of each rotary blade 19A-C is set so that it may bite into the ground according to the clockwise rotation of each steel pipe 12,14.

  In carrying out this stabilization method, a construction machine (not shown) is placed in the stepped portion 3 around the embankment slope 1. First, the steel pipe 12 with a check valve is placed at the head, and this is moved from the slope 2 of the embankment slope 1 to the ground. When the steel pipe 12 with a check valve has penetrated to an appropriate depth, the perforated steel pipe 14 is added via the coupling 15 and the rotary press-fitting is continued. At this time, since the rotary press-fitting of the steel pipes 12 and 14 (hollow pile body 16) proceeds by the biting of the spiral rotary blade 19A provided at the tip of the steel pipe 12 with a check valve, there is no discharge of earth and sand. The soil removal process is unnecessary. Moreover, since each steel pipe 12 and 14 is a small-diameter steel pipe (caliber 70 to 100 mm), it is sufficient to use a small construction machine. Therefore, the step portion 3 on which the construction machine is placed may be a narrow step. Construction can be performed without difficulty even in a narrow environment.

  And if almost the full length of the steel pipe 12 with a check valve of the head penetrates into the immovable layer B of the embankment slope 1, the rotary press-fitting of the hollow pile body 16 is stopped, and the steel pipe 12 with a check valve as shown in FIG. The injector 20 is inserted inside. The injector 20 is called a single packer, and includes a bulging body 21 bulging by air pressure and a discharge nozzle 22, and the bulging body 21 extends from a compressed air source on the ground. The air hose 23 and the grout pipe 24 extended from the ground grout supply source are connected to the discharge nozzle 22, respectively.

  The injector 20 is first inserted to the vicinity of the tip of the steel pipe 12 with a check valve, and at that position, compressed air is sent to the bulging body 21 through the air hose 23 to bulge it, and the steel pipe 12 with a check valve is bulged. The position is fixed. Subsequently, a grout cement grout such as grout cement milk or cement mortar is pumped to the discharge nozzle 22 through the grout tube 24. Then, the hardened material grout is discharged from the discharge nozzle 22 and filled in the tip of the steel pipe 12, and by the pressure, the check valve 11 corresponding to the filling area is opened and the hardened material grout is turned into the steel pipe 12 with the check valve. Are radially ejected around the periphery of the steel pipe 12 and injected under pressure into the ground around the steel pipe 12.

  In this way, the grout fixing layer 17 in which the surrounding earth and sand and the hardened material grout are mixed is formed around the steel pipe 12 with the check valve. The grout fixing layer 17 connects the injector 20 to the check valve. While being pulled up at a pitch corresponding to an arrangement pitch of 11, the discharge of the curing material grout is repeated to gradually expand upward. At this time, since the spiral rotor blade 19B exists at the rear end portion of the steel pipe 12 with the check valve, the rotor blade 19B allows the hardened material grout to enter the moving layer C side, that is, around the perforated steel pipe 14. As a result, the opening 13 of the perforated steel pipe 14 is not blocked by the hardened material grout. Therefore, the rotor blade 19B functions as a shielding plate that suppresses the flow of the hardened material grout to the moving layer C side.

  The above-described pressure injection of the hardened material grout is carried out over almost the entire length of the steel pipe 12 with a check valve, so that the almost entire length of the steel pipe 12 with the check valve is passed through the grout fixing layer 17 to the fixed layer of the embankment slope 1. The placement of the restraining pile 10 which is firmly fixed to B and in which the hollow pile body 16 and the grout fixing layer 17 are integrated is finished. In the restraining pile 10 thus placed, the steel pipe 12 with a check valve on the leading side is fixed to the immovable layer (fixing region) B of the embankment slope 1 via the grout fixing layer 17 and has a large-diameter spiral rotation. Since it is constrained in the removal direction by the blades 19A, it exerts a large proof strength against tension, bending, shearing and the like. Especially in this embodiment, since the steel pipe 12 with a node which has the node 18 in the outer peripheral surface is used as the steel pipe 12 with a check valve, the drawing resistance of the steel pipe 12 is increased, and the supporting force of the restraining pile 10 is further increased. To do.

  On the other hand, since a perforated steel pipe 14 that functions as a drain pipe is embedded in the moving layer (main active area) C of the embankment slope 1, groundwater such as seepage water and spring water flows into the steel pipe 14 from the opening 13. Then, it is discharged outside through the steel pipe 14. Therefore, the moving layer C is not loosened by the groundwater, and the collapse of the embankment slope 1 is prevented in advance. Especially in this embodiment, since the hollow pile body 16 is inclined at a slight inclination angle (0 to 30 degrees) with respect to the horizontal axis L, drainage proceeds smoothly through the perforated steel pipe 14, and the moving bed C Looseness is further suppressed.

  Here, the length of the perforated steel pipe 14 is set so that the spiral rotary blade 19C provided at the rear end portion thereof is slightly buried in the soil. As a result, the earth and sand are prevented from slipping out from the moving layer C, and the embankment slope 1 is further stabilized. In other words, a process of providing a separate bearing plate becomes unnecessary, and the construction cost is reduced accordingly.

  In addition, the opening 13 of the perforated steel pipe 14 may have a structure provided with a filter for preventing inflow of earth and sand. In this case, the size and shape of the opening 13 are arbitrary. The perforated steel pipe 14 can be replaced with another drain pipe having the same strength as the steel pipe.

  Moreover, in the said embodiment, although the spiral rotary blades 19A and 19B were provided in the front-end | tip part and the rear-end part with respect to the steel pipe 12 with a non-return valve, the spiral rotary blade 19B of the rear end side is reverse. It may replace with the steel pipe 12 with a stop valve, and may be made to provide in the front-end | tip part of the perforated steel pipe 14, or the coupling 15. FIG.

  Furthermore, in the said embodiment, although the single packer provided with one bulging body 21 was used as the injection machine 20 which inject | pours pressure injection of hardening material grout, as this injection machine 20, two bulging bodies are used. A so-called double packer type may be used. In this case, the air space between the two bulging bodies becomes a pressure chamber, and the hardened material grout is ejected from the check valve 11 through this pressure chamber.

It is sectional drawing which shows typically the state of the slope after implementing the stabilization construction method which is one embodiment of this invention. It is sectional drawing which shows the driving | running state of the suppression pile driven by this stabilization construction method. It is a side view which shows the structure of the steel pipe with a non-return valve and the perforated steel pipe which comprise the deterrent pile put up by this stabilization construction method. It is sectional drawing which shows the implementation condition which pressurizes and injects hardening material grout from a steel pipe with a check valve using an injection machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Embankment slope 2 Slope 10 Suppression pile 11 Check valve 12 Steel pipe with check valve 13 Opening 14 Perforated steel pipe 16 Hollow pile body 17 Grout fixation layer 19A-C Spiral rotary blade

Claims (4)

Prepare a steel pipe with a small diameter check valve having spiral rotor blades at least at the front end and the rear end, and a small diameter perforated steel pipe that functions as a drain pipe. Both steel pipes are rotationally press-fitted into the ground while adding steel pipes so that the steel pipe with check valve penetrates into the fixed layer in the ground, and the perforated steel pipe is positioned in the moving layer above the fixed layer. Then, the check valve is opened from the inside of the steel pipe with the check valve, and the hardened material grout is pressurized and injected into the ground around the steel pipe, and provided at the rear end of the steel pipe with the check valve. A slope stabilization method characterized in that a spiral rotating blade is used as a shielding plate that suppresses the flow of hardened material grout to the moving layer side, and the steel pipe with a check valve is fixed to the non- moving layer . Instead of the spiral rotor blade at the rear end of the steel pipe with check valve, a spiral is connected to the tip of the perforated steel pipe, or to the coupling connecting the steel pipe with check valve and the perforated steel pipe. The slope stabilization method according to claim 1, further comprising: a cylindrical rotor blade. The diameter stabilization method of the steel pipe with a check valve and the perforated steel pipe is 70-100 mm, The stabilization method of the slope of Claim 1 or 2 characterized by the above-mentioned.   4. The slope stability according to claim 1, wherein a spiral rotor blade is provided at a rear end portion of the perforated steel pipe, and the rotor blade is used as a pressure bearing plate for pressing the surface of the slope. Chemical method.

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