JP2008063871A - Soil improving method and soil improving equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce excavation resistance during penetration into ground, while suppressing an increase in cost. <P>SOLUTION: A rotating shaft penetrates the ground by excavating the ground by means of an excavating head 120 at the leading end of the rotating shaft 101. During the penetration of the rotating shaft, pressure water and compressed air are supplied from a pressure-water supply device 213 and an compressed-air supply device 223 on the ground; an air feed pipe 220 is connected to an insertion opening 215 of a water pipe 210, so that the pressure water and the compressed air are merged together on this side of the inlet of a supply pipeline; and merged fluids are sent into the excavating head through the supply pipeline, and jetted toward excavated soil from an ejection port of a jet box 130 which is provided on the backside of a spiral blade 121. A check valve 224 for inhibiting the flow of the fluid from the side of a confluence, and a safety valve 225 for releasing pressure equal to/exceeding specified pressure are provided on the air feed pipe 220. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ground improvement method and a ground improvement device capable of facilitating construction by reducing resistance when penetrating the rotary shaft into the ground while excavating the ground with an excavation head equipped at the tip of the rotary shaft. Is.

  In the ground improvement method, a fluid is sent from the ground to the tip of the rotating shaft penetrating into the ground, and the fluid is injected into the excavated ground from a stirring blade at the tip of the rotating shaft or a discharge port provided in the drilling head. Generally done.

  In Patent Document 1 and Patent Document 2, compressed air and liquid material are sent from the ground supply means to the tip of the rotating shaft through another path in the rotating shaft, and liquid material is added to the compressed air by a mixing ejector attached to the stirring blade. Is disclosed that is jetted in the presence of a gas.

  FIG. 11 shows the configuration of the ground improvement device described in Patent Document 1 as an example.

  In FIG. 11, a supply pipe 502 for compressed air and a supply pipe 503 for liquid material are provided inside a rotary shaft 501 penetrating into the ground. Pipes 504a and 505a from the compressed air supply device 504 and the liquid material supply device 505 are connected to the upper end inlets 502a and 503a, respectively.

Further, the lower end outlets 502 b and 503 b of the supply pipe lines 502 and 503 are connected to a mixing ejector 507 provided on the stirring blade 506 at the lower end of the rotating shaft 501. Then, the mixed ejector 507 jets the compressed air sent through the supply pipe 502 together with the liquid material sent through the supply pipe 503.
Japanese Patent No. 3416774 JP 2003-74049 A

  By the way, there is a method in which supply pipes (paths) 502 and 503 are provided inside the rotary shaft 501 for each fluid type, and the fluid is mixed and ejected by the mixing ejector 507 immediately before being finally ejected toward the soil. In addition, a large number of supply pipes 502 and 503 must be secured inside the rotating shaft 501, and the swivel joint and the in-shaft piping are complicated, resulting in a problem that the equipment cost increases.

  In a normal construction apparatus, it is common to provide only one or two supply pipelines in the rotating shaft, and the technology described in Patent Document 1 or Patent Document 2 is applied to such equipment. It is very difficult to do.

  In consideration of the above circumstances, the present invention reduces the excavation resistance when penetrating into the ground while suppressing an increase in cost, and improves the construction efficiency and the ground improvement device used in the construction method The purpose is to provide.

  In the ground improvement method of the invention of claim 1, the ground is improved by excavating the ground with an excavation head equipped at the tip of the rotating shaft and penetrating the rotating shaft into the ground. In the ground improvement method in which a fluid is sent from the ground through the supplied supply line, and the fluid is jetted from the discharge port provided in the excavation head toward the excavated soil, as the fluid supply device, A compressed air supply device, and the compressed water and compressed air supplied from both supply devices are merged before being introduced into the inlet of the supply pipeline, and then fed to the excavation head through the supply pipeline, It sprays toward excavation soil from the said discharge outlet, It is characterized by the above-mentioned.

  Invention of Claim 2 is the ground improvement construction method of Claim 1, Comprising: The water supply pipe extended from the said pressurized water supply apparatus is made to join the air supply pipe extended from the said compressed air supply apparatus, and pressurized water is combined. A check valve that prevents the flow of fluid from the merging point side on the air supply pipe extending from the compressed air supply device before the merging point is joined to the flow, and a specified pressure or more. And a safety valve for relieving the pressure.

  A third aspect of the invention is the ground improvement method according to the first aspect, wherein the excavation head is provided with a spiral wing having a digging claw at a lower end edge, and a fluid is disposed on a back side in a rotation direction of the spiral wing. An ejection box is provided, and in the ejection box, a discharge port that discharges fluid toward the front in the rotational direction of the spiral blade, a discharge port that discharges fluid toward the rear, and outward in the rotational radial direction of the spiral blade At least one of discharge ports for discharging fluid is provided.

  Invention of Claim 4 is the ground improvement construction method of Claim 3, Comprising: The discharge outlet which discharges the fluid toward the front of the rotation direction of a spiral wing | blade to the said injection box, and discharges the fluid toward back There are three types of discharge ports, a discharge port that discharges fluid toward the outside in the rotational radius direction of the spiral wing, and one of the discharge ports is selectively selected according to the conditions of the excavation ground It is characterized in that the fluid is discharged to discharge the fluid and the others are blocked.

  According to a fifth aspect of the present invention, there is provided a rotary shaft that is vertically supported and drilled into the ground by a drilling head equipped at a tip, a drive device that moves up and down while rotating the rotary shaft, and the rotary shaft A first supply pipe arranged along the excavation head, a discharge port provided in the excavation head, for discharging the fluid fed through the first supply pipe toward the excavation soil, and provided on the ground The pressurized water supply device and the compressed air supply device, the water supply pipe for feeding the pressurized water supplied from the pressurized water supply device to the inlet of the first supply pipe, and the front of the inlet of the first supply pipe An insertion port provided on the water supply pipe, an air supply pipe for joining the compressed air supplied from the compressed air supply device to the insertion port, a fluid provided on the air supply pipe, and a fluid from the insertion port side A check valve that prevents the backflow of the check valve, and a feed upstream of the check valve. It is equipped on the tube, characterized by comprising a safety valve for releasing the pressure of more than the specified pressure.

  A sixth aspect of the present invention is the ground improvement device according to the fifth aspect, wherein the excavation head is provided with a spiral wing having a digging claw at a lower end edge, and a fluid is provided on the back side in the rotational direction of the spiral wing. The ejection box is provided with a discharge port that discharges fluid toward the front in the rotational direction of the spiral blade, a discharge port that discharges fluid toward the rear, and outward in the rotational radial direction of the spiral blade. Any one of discharge ports for discharging fluid is provided.

  A seventh aspect of the invention is the ground improvement device according to the sixth aspect of the invention, wherein the ejection box discharges fluid toward the front in the rotational direction of the spiral wing and discharges fluid toward the rear. There are three types of discharge ports, a discharge port for discharging fluid and a discharge port for discharging fluid toward the outside in the rotational radius direction of the spiral wing, so that only one of them can be selectively opened. It is characterized by.

  Invention of Claim 8 is the ground improvement apparatus of any one of Claims 5-7, Comprising: The stirring blade located in the upper side of the said excavation head, and was provided in the front-end | tip of the said rotating shaft, Separately from the first supply pipeline, a second supply pipeline arranged along the rotation axis, and a stabilizer sent from the ground through the second supply pipeline, the rotational height of the stirring blades The stabilizer supply port for discharging into the excavated soil, the stabilizer supply pumping device provided on the ground, and the inlet of the second supply pipe arranged along the rotation axis, the pump supply device A stabilizer feed pipe for introducing a stabilizer fed by pressure and a stabilizer sent from the stabilizer feed feeder are introduced into the inlet of the first supply pipe as necessary. And a flow path changing means.

  Invention of Claim 9 is the ground improvement apparatus of Claim 8, Comprising: The said flow-path change means is a 1st which opens and closes the connection pipe which connects the said pressure feed pipe and a water feed pipe, and this communication pipe A valve, a second valve that is closed to prevent backflow of fluid upstream of the connecting pipe connection point upstream of the connecting pipe connection point when the first valve is open, and the connecting pipe connection A third valve is provided on the pumping pipe downstream from the point and is controlled to open and close in conjunction with the first valve.

  Invention of Claim 10 is the ground improvement apparatus of any one of Claim 5-9, Comprising: The stirring blade located in the upper side of the said excavation head, and was provided in the front-end | tip of the said rotating shaft, Separately from the first supply pipeline, a second supply pipeline arranged along the rotation axis, and a stabilizer sent from the ground through the second supply pipeline, the rotational height of the stirring blades The stabilizer supply port for discharging into the excavated soil, the stabilizer supply pumping device provided on the ground, and the inlet of the second supply pipe arranged along the rotation axis, the pump supply device A stabilizer feed pipe for introducing the stabilizer fed by pressure, an air inlet provided on the pump feed pipe, and an air inlet on the pump feed pipe for compressed air supplied from the compressed air supply means. Introducing compressed air into a stabilizer that is pumped through the pumping pipe Characterized by comprising the, the.

  The invention of claim 11 is the ground improvement device of claim 10, wherein a branch point is provided on the air supply pipe downstream of the check valve, and the air introduction pipe is branched from the branch point. Further, the present invention is characterized in that there is provided a switching valve means for switching the introduction destination of the compressed air supplied through the air feeding pipe to the insertion port on the water feeding pipe or the air inlet on the pressure feeding pipe.

  According to the first aspect of the present invention, since the mixed fluid of the pressurized water and the compressed air is ejected from the fluid discharge port provided in the excavation head toward the excavation soil, the friction between the excavation head and the earth and sand is efficiently reduced. And excavation resistance can be reduced. In addition, since the pressurized water and compressed air are merged before being introduced to the inlet of the supply pipe and then sent to the excavation head through the supply pipe, it is possible to avoid increasing the number of supply paths provided along the rotation axis. , Excess cost increase can be suppressed.

  According to the second aspect of the present invention, the compressed air is mixed with the pressurized water by joining the air feeding pipe for feeding the compressed air to the water feeding pipe for feeding the pressurized water. It can be introduced at the entrance of the road. In addition, since a check valve and a safety valve are provided on the air supply pipe before the confluence, even if the pressure in the water supply pipe suddenly rises due to a certain moment, the check valve operates to generate pressurized water. Intrusion into the compressed air supply device can be reliably prevented. In addition, even when the pressure in the air supply pipe suddenly rises for some reason, the safety valve can be used to suppress a pressure rise above a specified level. As a result, the compressed air supply device can be safely protected.

  According to the invention of claim 3, since the fluid injection box is provided on the back side of the spiral blade of the excavation head, and the discharge port for determining the fluid injection direction is provided in the injection box, the direction toward the predetermined direction. A mixed fluid of pressurized water and compressed air can be injected. Moreover, since the ejection port is provided in the injection box, the ejection port in the necessary direction can be arranged with a reasonable layout.

  According to the fourth aspect of the present invention, the discharge port to be opened and the discharge port to be closed are determined in advance, so that the fluid is discharged forward or backward in the rotational direction of the spiral blade or outward in the rotational radial direction of the spiral blade. can do. Therefore, when excavating ground with low adhesive strength such as sandy system, the excavation resistance in front of the spiral wing is discharged by discharging the mixed fluid of pressurized water and compressed air toward the front in the rotation direction of the spiral wing. Can be reduced. In addition, when excavating highly viscous ground, by discharging the mixed fluid of pressurized water and compressed air toward the rear in the rotational direction of the spiral wing, the resistance to the earth and sand moving along the back of the spiral wing is reduced. Can reduce the excavation resistance. Moreover, when excavating for constructing a joint pile, the rotational resistance of the outer periphery of a spiral blade can be reduced by discharging the fluid mixture of water and air toward the radial direction outward of the spiral blade.

  According to the invention of claim 5, since the mixed fluid of pressurized water and compressed air can be ejected from the fluid discharge port provided in the excavation rod toward the excavation soil, the friction between the excavation head and the earth and sand Can be efficiently reduced, and excavation resistance can be reduced. Further, the pressurized water and the compressed air can be fed to the excavation head through the first supply pipe after being merged before being introduced into the inlet of the first supply pipe, and thus provided along the rotation axis. It is not necessary to increase the number of supply paths, and an extra cost increase can be suppressed.

  In addition, since a check valve and a safety valve are provided on the air supply pipe before joining the water supply pipe, even if the pressure in the water supply pipe suddenly rises due to any moment, the check valve operates to Water can be reliably prevented from entering the compressed air supply device, and even if the pressure in the air supply pipe suddenly rises for some reason, the safety valve works to suppress the pressure rise above the specified level. As a result, the compressed air supply device can be safely protected.

  According to the sixth aspect of the present invention, the fluid injection box is provided on the back side of the spiral blade of the excavation head, and the discharge port for determining the fluid injection direction is provided in the injection box. A mixed fluid of pressurized water and compressed air can be injected. Moreover, since the ejection port is provided in the injection box, the ejection port in a necessary direction can be arranged with a reasonable layout.

  According to the invention of claim 7, by determining the discharge port to be opened and the discharge port to be closed, the fluid is directed forward or backward in the rotational direction of the spiral blades or outward in the rotational radial direction of the spiral blades. It can be discharged. Therefore, when excavating ground with low adhesive strength such as sandy system, the excavation resistance in front of the spiral wing is discharged by discharging the mixed fluid of pressurized water and compressed air toward the front in the rotation direction of the spiral wing. Can be reduced. In addition, when excavating highly viscous ground, the mixed fluid of pressurized water and compressed air is discharged toward the rear in the rotational direction of the spiral wing, thereby reducing the resistance of the earth and sand moving along the back of the spiral wing. And thereby reduce excavation resistance. Moreover, when excavating for constructing a joint pile, the rotational resistance of the outer periphery of a spiral blade can be reduced by discharging the fluid mixture of water and air toward the radial direction outward of the spiral blade.

  According to the invention of claim 8, in addition to the normal usage of discharging the stabilizer from the discharge port provided at the rotational height of the stirring blade and mixing with the local soil, by providing the flow path changing means, When necessary, the stabilizer can be discharged from the discharge port of the excavation head. Therefore, even at the depth of the excavation head, the stabilizer can be supplied into the ground.For example, in the case of a soft ground, the supply of the pressurized water and the supply of the stabilizer are switched at the time of penetration of the rotating shaft. By alternately discharging the pressure water and the stabilizing material from the discharge port of the excavating head, the stabilizing material can be mixed into the excavated soil at the time of penetration. In the case of hard ground, the rotary shaft is inserted into the ground while discharging the pressure water from the discharge port of the excavation head, and when the rotary shaft is pulled out after the penetration, the stabilizer is discharged at the rotational height of the stirring blade. In addition, the stabilizing material can be discharged from the discharge port of the excavation head instead of the pressurized water, so that the stabilizing material can be mixed with the local soil.

  According to the ninth aspect of the present invention, the flow path changing means can be configured simply by providing the connecting pipe and the three valves in the piping system composed of the pressure feed pipe and the water feed pipe. The stabilizer can be appropriately changed to introduce not only the second supply pipe but also the first supply pipe.

  According to the invention of claim 10, an air introduction port is provided on the pressure feeding pipe of the stabilizing material discharged at the rotational height of the stirring blade, and compressed air can be mixed into the stabilizing material from the air introduction port. Therefore, the fluidity of the stabilizer can be adjusted by mixing the compressed air, and the stirring performance can be improved.

  According to the eleventh aspect of the present invention, the air introduction pipe for introducing the compressed air into the air introduction port provided on the pressure feed pipe of the stabilizer is provided on the air feed pipe downstream from the check valve, and the switching valve means is provided. Since the introduction destination of the compressed air can be switched by this, the compressed air can be effectively used for both the excavation and the agitation while suppressing the equipment cost.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the ground improvement device that performs the ground improvement method of the present embodiment includes a rotating shaft 101 that is supported so as to be vertically movable along a guide 103 a of a leader 103 of a base machine 102. , A wire suspension type lifting drive device 104 that lifts and lowers the rotary shaft 101, and a rotary drive device 105 that is installed in the lifting unit of the lift drive device 104. While rotating the rotary shaft 101 with the rotary drive device 105, the ground is excavated by the excavating and stirring means 110 attached to the tip of the rotary shaft 101, and a stabilizer is injected into the excavated soil and stirred and mixed. To improve the ground. The rotary shaft 101 is guided for excavation and penetration by a lower steadying mechanism 150 provided under the leader 103.

  FIG. 2 is a diagram showing the system configuration of the main part of the ground improvement device, and FIG. 3 is a diagram showing the configuration of the excavation stirring means 110 provided at the tip of the rotating shaft 101.

  Although not shown in the figure, a first supply pipe for distributing a friction reducing fluid mixed with pressurized water and compressed air is provided along the rotary shaft 101, and a stabilizer in a separate system. And a second supply line for stabilizing material to be circulated.

  On the ground, a milk plant pumping pump 202 and a flow meter 203 are provided as a stabilizer feed pump 205, and the stabilizer fed from the milk plant pump 202 via the flow meter 203 is supplied to the stabilizer. Via the pipe 201 and the swivel joint 108, the gas is introduced into the upper end inlet of the second supply pipe for the stabilizer disposed in the rotary shaft 101.

  In addition, a pressurized water supply device 213 and a compressed air supply device 223 are provided on the ground. The pressurized water supply device 213 is composed of a hydropumping device 211 composed of a pressurizing pump and a hydration control device 212 that controls the pressure and flow rate of the pressurized water via the waterpipe 210 and the swivel joint 108, and the rotating shaft 101 is introduced into the upper end inlet of the first supply pipe which is mainly a flow path for the friction reducing fluid.

  An insertion port 215 is provided immediately before the introduction portion of the water supply pipe 210 to the swivel joint 108, and the distal end of the air supply pipe 220 extending from the compressed air supply device 223 is connected to the insertion port 215. .

  The compressed air supply device 223 includes an air compressor 221 and an air control device 212 that controls the pressure and flow rate of the air compressor 221, and the compressed air sent through the air supply pipe 220 passes through the water supply pipe 210 from the insertion port 215. It is designed to merge with flowing pressure water.

  Further, since there is a possibility that the pressure of the water supply pipe 210 and the pressure of the air supply pipe 220 may be greatly different from each other, a check valve 224 for preventing the backflow of fluid from the insertion port 215 side is provided on the air supply pipe 220. A safety valve 225 is provided on the air supply pipe 220 on the upstream side of the check valve 224 to release a pressure higher than a specified pressure.

  Further, between the pressure feeding pipe 201 and the water feeding pipe 210, the first feeding pipe, which is usually a pressurized water flow path, is connected to the stabilizing material sent from the stabilizing material pressure feeding device 205 as necessary. There is provided a flow path changing means 300 to be introduced at the inlet. The flow path changing means 300 in this case includes a connecting pipe 301 that connects the branch point 204 on the pressure feed pipe 201 and a branch point 214 on the water feed pipe 210, a first valve 311 that opens and closes the connecting pipe 301, When the first valve 311 is open, it communicates with the second valve 312 that is closed to prevent the backflow of the fluid upstream of the connection point (branch point 214) of the communication pipe 301 to the upstream side of the water supply pipe 210. A third valve 313 is provided on the pressure-feeding pipe 201 on the downstream side of the connection point (branch point 204) of the pipe 301 and is controlled to open and close in reverse with the first valve 311. The first to third valves 311 to 313 are all electromagnetic valves and are controlled in association with each other by a control device (not shown).

  On the other hand, as shown in FIG. 3, the excavation stirring means 110 is provided with an excavation head 120 at the forefront of the rotating shaft 101, and a plurality of stirring blades 112 and co-rotating plates 113 on the upper side. It is provided alternately in the stage. In the present embodiment, the rotation radius of the excavation head 120 is set smaller than the rotation radius of the stirring blade 112.

  The stirring blade 112 is a bar-shaped member that extends linearly from the rotation shaft 101 in the radial direction, and includes a blade plate that is inclined with respect to the axis of the rotation shaft 101. The lowermost stirring blade 112 has an excavation claw 114 at its lower end so that it can perform not only agitation but also an excavation function. In addition, on the back surface in the rotational direction of the upper stirring blade 112, a discharge box (discharge port) 115 for a stabilizing material sent through a supply pipe line in the rotary shaft 101 is provided. The discharge of the stabilizing material from the discharge box 115 is performed mainly when the rotary shaft 101 is pulled up.

  In addition, as the excavation head 120, two spiral blades 121 having a large number of excavation claws 122 at the lower end edge 121a are provided. The two spiral wings 121 are arranged 180 degrees symmetrically around the rotation axis 101, and each is wound in an angle range of 180 degrees. That is, each spiral blade 121 is provided for a half pitch.

  In addition, the lower end edge 121a of each spiral blade 121 is linearly inclined upward from the outer peripheral end toward the inner peripheral end, and the tip of the excavation head 120 configured by the lower end edges 121a of the two spiral blades 121 is The center portion is recessed and the peripheral portion protrudes downward.

  Further, as shown in FIG. 4, a fluid ejection box 130 for reducing friction is provided on the back side in the rotational direction of one spiral blade 121. As shown in FIG. 5, the spray box 130 includes a rectangular block-shaped box body 131 and covers 141, 142, and 143 that are fixed to necessary portions of the outer surface with bolts.

  The box body 131 has a fluid inlet 132 on one end face in the longitudinal direction and a branch passage 133 connected to the inlet 132 inside, and the branch passage 133 is connected to both end faces in the short side direction and the other end face in the longitudinal direction. The discharge port 135 has a series of discharge ports 135, 136, and 137 attached to the back surface of the spiral blade 121, the discharge port 135 faces forward in the rotational direction of the spiral blade 121, and the discharge port 136 rotates the spiral blade 121. The discharge port 137 is directed outward in the rotational radial direction of the spiral blade 121. In addition, a pipe 118 at the tip of a supply line for a fluid for reducing friction disposed through the rotary shaft 101 is connected to the inlet 132 of the box body 131.

  The covers 141, 142, and 143 are provided in accordance with the respective discharge ports 137, and can be attached arbitrarily. In the illustrated example, only one of the covers 141 is for opening having the injection port 141a, and the other covers 142 and 143 are for closing. When the opening cover 141 is attached, the discharge port 135 can be opened, and when the closing covers 142 and 143 are attached, the discharge ports 136 and 137 can be closed. That is, by replacing the covers 141 to 143, only one of the three types of discharge ports can be selectively opened.

  Next, a ground improvement method using the ground improvement device having the above-described configuration will be described.

  In improving the ground, first, the excavation head 120 is lowered toward the ground while rotating the rotary shaft 101 by the lift drive device 104 and the rotary drive device 105. Accordingly, the ground is excavated by the excavation head 120 provided at the tip of the rotary shaft 101, and the rotary shaft 101 penetrates into the ground.

  At the time of penetration, pressurized water is supplied from the pressurized water supply device 213 and compressed air is supplied from the compressed air supply device 223. Then, when the supplied pressurized water and compressed air pass through the insertion port 215, they merge and are introduced into the upper end inlet of the first supply pipe line in the rotating shaft 101 via the swivel joint.

  Then, the mixed fluid of compressed water and compressed air sent to the excavation head 120 through the first supply pipe is ejected toward the excavated soil from the discharge ports 135, 136, and 137 opened in the ejection box 130. In the illustrated example, since the discharge port 135 is open, the mixed fluid is discharged toward the front in the rotation direction of the spiral blade 121 through the discharge port 135 and the injection port 141a of the cover 141.

  Thus, since the fluid mixture of pressurized water and compressed air is ejected toward the excavation soil from the fluid discharge ports 135 to 137 provided in the excavation head 120, the friction between the excavation head 120 and the earth and sand is efficiently reduced. And excavation resistance can be reduced. As a result, an effect of reducing the deflection θ (axial deviation) of the rotating shaft 101 due to excavation resistance bias as shown in FIG. 1 can be expected.

  Further, since the pressurized water and the compressed air are merged before being introduced into the inlet of the first supply pipe, and sent to the excavation head 120 through the first supply pipe, the supply provided along the rotary shaft 101 It is not necessary to increase the number of routes, and an extra cost increase can be avoided.

  In addition, since the insertion port 215 is provided in the middle of the water supply pipe 210 for sending the pressurized water, and the compressed air can be mixed with the pressure water simply by connecting the tip of the air supply pipe 220 for sending the compressed air to the insertion port 215, The mixed two fluids can be introduced into the inlet of one supply line with a simple configuration.

  In addition, since the check valve 224 and the safety valve 225 are provided on the air supply pipe 220 in front of the merging point, even when the pressure in the water supply pipe 210 suddenly rises due to something, the check valve 214 The operation can reliably prevent the pressurized water from entering the compressed air supply device 223 side. In addition, even when the pressure in the air supply pipe 220 suddenly increases for some reason, the safety valve 225 works to suppress a pressure increase beyond a specified level, so that the compressed air supply device 223 can be safely protected. Can do.

  Moreover, since the fluid injection box 130 is provided on the back side of the spiral blade 121 of the excavation head 120 and the discharge ports 135 to 137 for determining the fluid injection direction are provided in the injection box 130, the direction toward a predetermined direction. A mixed fluid of pressurized water and compressed air can be injected. In addition, since the ejection ports 135 to 137 are provided in the ejection box 130, the ejection ports 135 to 137 facing in a necessary direction can be arranged with a reasonable layout.

  Further, by determining a discharge port to be opened and a discharge port to be closed, an opening cover with an injection port is attached to the discharge port to be opened, and a cover for closing is attached to the discharge port to be closed. The fluid can be selectively discharged toward the front or rear in the rotational direction, or outward in the rotational radial direction of the spiral blade 121.

  Therefore, when excavating a ground having a low adhesive force such as a sandy system, by discharging a fluid mixture of pressurized water and compressed air toward the front in the rotational direction of the spiral blade 121, Drilling resistance can be reduced. Further, when excavating a highly viscous ground, by discharging a mixed fluid of pressurized water and compressed air toward the rear in the rotational direction of the spiral blade 121, the earth and sand moving along the back surface of the spiral blade 121 Resistance can be reduced, thereby reducing excavation resistance. Furthermore, when performing excavation for constructing the joint pile, the rotational resistance of the outer periphery of the spiral blade 121 can be reduced by discharging a mixed fluid of water and air toward the radially outward direction of the spiral blade 121. it can.

  When the penetration of the rotary shaft 101 to a predetermined depth is completed, the milk plant pressure feed pump 202 is operated, and the stabilizer is discharged from the discharge box 115 of the stirring blade 112 via the pressure feed pipe 201 and the second supply line. Rotating the rotating shaft 101 while discharging, the local soil and the stabilizer are stirred and mixed, and an improved body (pile body) is constructed in a cylindrical shape. As described above, the ground can be improved efficiently.

  In addition, as shown in FIG. 6, when the rotation radius of the excavation head 120 is smaller than that of the stirring blade 112, the diameter D1 of the excavated hole bottom MA is an improved body (a hole in which a pile body is constructed is indicated by a symbol MB). Therefore, when constructing a pile body with a predetermined diameter and a predetermined depth, it is out of specification by the height of the excavation head 120, and therefore it is necessary to excavate an extra depth by that amount. However, if the rotational radii of the agitating blade 112 and the excavation head 120B are set to be approximately equal as in the excavation stirring means 110B shown in FIGS. 7 and 8, the diameter D1 of the excavated hole bottom MA is improved ( Since the hole in which the pile body is constructed is equal to the diameter D2), the entire length in the hole can be configured as a pile body having an effective diameter. Therefore, it is more advantageous when the increase in excavation resistance is not taken into consideration.

  In addition to the normal usage of discharging the stabilizer from the discharge box 115 provided at the rotational height of the stirring blade 112 and mixing it with the local soil as described above, the flow path changing means 300 is provided. When necessary, the stabilizer can be discharged from the injection box 130 of the excavation head 120 via the water supply pipe 210 and the first supply conduit, and the stabilizer can be discharged into the ground at the depth of the excavation head 120. It can also be supplied.

  For example, when the stabilizer is discharged from both the jet box 130 of the excavation head 120 and the discharge box 115 of the stirring blade 112 at an appropriate ratio (the ratio can be freely changed from 10: 0 to 0:10), the second is used. The valve 312 is closed and the open / close ratio of the first valve 311 and the third valve 313 is set appropriately. By doing so, the stabilizer can be discharged into the soil from the discharge box 115 of the stirring blade 112 through the pressure feed pipe 201 and the second supply pipe, and the injection of the excavation head 120 through the water feed pipe 210 and the first supply pipe. A stabilizer can be discharged from the box 130 into the soil.

  Therefore, for example, in the case of soft ground, when the rotary shaft 101 penetrates, the pressure water and the stabilizing material are alternately discharged from the injection box 130 of the excavation head 120 while switching the supply of the pressurized water and the supply of the stabilizing material. Thus, at the time of penetration, the stabilizer can be mixed with the excavated soil.

  In the case of hard ground, the rotating shaft 101 penetrates into the ground while discharging the pressurized water from the jet box 130 of the excavation head 120, and the rotational height of the stirring blade 112 is pulled out when the rotating shaft 101 is pulled out. In addition, the stabilizing material is discharged from the spray box 130 of the excavation head 120 instead of the pressurized water, so that the stabilizing material can be mixed with the local soil.

  In addition, the flow path changing means 300 can be easily configured only by providing the connecting pipe 301 and the three valves 311 to 313 in the piping system including the pressure feeding pipe 201 and the water feeding pipe 210.

  FIG. 9 is a diagram showing a main configuration of another embodiment of the present invention.

  In the ground improvement device of this embodiment, an air introduction port 206 is provided on the pressure-feed pipe 201 of the stabilizer, and the air introduction port 206 branches from a branch point 226 provided on the air supply pipe 220 downstream of the check valve 224. The tip of the air introduction pipe 220A provided in this way is connected so that the compressed air can be mixed into the stabilizer fed through the pressure feed pipe 201. In addition, as a switching valve means for switching the introduction destination of the compressed air supplied through the air supply pipe 220 to the insertion port 215 on the water supply pipe 210 or the air introduction port 206 on the pressure supply pipe 201, the branch point 226 is provided. Two valves 227 and 228 are provided on the downstream side.

  By adopting such a configuration, when excavating the ground, by opening the valve 227 and closing the valve 228, compressed air can be mixed into the pressurized water, and the mixed fluid can be fed into the excavation head 120. The above-described effects can be exhibited. Further, during agitation, by closing the valve 227 and opening the valve 228, the compressed air can be mixed into the stabilizing material, and the stabilizing material mixed with the compressed air can be discharged into the agitated excavated soil. Therefore, the fluidity of the stabilizer can be adjusted by mixing compressed air, and the stirring performance can be improved.

  In addition, the air introduction pipe 220A prepared for that purpose is branched on the air supply pipe 220 downstream of the check valve 224, and the introduction destination of the compressed air is switched by the valves 227 and 228. While being suppressed, the compressed air can be effectively used for both excavation and stirring.

  FIG. 10 is a diagram showing a configuration of main parts of still another embodiment of the present invention.

  In the ground improvement device of this embodiment, a safety valve 225 is not directly provided on the pipeline between the air control device 222 and the check valve 224 as shown in FIG. 2, but a tank 229 is provided on the pipeline, A safety valve 225 is attached to the tank 229. Other configurations are the same as those of the embodiment of FIG.

  In such a configuration, even if the backflow fluid (water or milk) has penetrated the check valve 224, it can be discharged to the outside by the safety valve 225 via the tank 229, to the air control device. Water and milk backflow can be reliably prevented.

It is a side view which shows the outline | summary of the whole structure of the ground improvement apparatus which implements the ground improvement construction method of embodiment of this invention. It is a figure which shows the system configuration | structure of the principal part of a ground improvement apparatus. It is a side view which shows the structure of the excavation stirring means provided in the front-end | tip of the rotating shaft of a ground improvement apparatus. It is the perspective view seen upside down of the excavation head which comprises the said excavation stirring means. It is a block diagram of the injection box provided in the back surface of the spiral blade of the said excavation head, (a) is sectional drawing, (b) is a side view. It is sectional drawing which shows the state which is excavating a hole in the ground by the excavation stirring means of the ground improvement apparatus of embodiment of this invention. It is a side view which expands and shows the principal part of the ground improvement apparatus of other embodiment of this invention. It is sectional drawing which shows the state which is excavating a hole in the ground by the excavation stirring means of the ground improvement apparatus of FIG. It is a figure which shows the system configuration | structure of the principal part of the ground improvement apparatus of further another embodiment of this invention. It is a figure which shows the system configuration | structure of the principal part of the ground improvement apparatus of another embodiment of this invention. It is a side view which shows the structure of the conventional ground improvement apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Rotating shaft 104 Lifting drive device 105 Rotation drive device 110,110B Excavation stirring means 112 Stirring blade 115 Stabilizer discharge box (discharge port)
120, 120B Excavation head 121 Spiral blade 121a Lower end edge 122 Excavation claw 130 Injection box (discharge port)
135 to 137 Discharge port 201 Pressure feed pipe 204 Branch point (connection point)
205 Stabilizer Pressure Supply Device 206 Air Inlet 210 Water Supply Pipe 213 Pressure Water Supply Device 214 Branch Point (Connection Point)
215 Insertion (confluence)
220 Air supply pipe 223 Compressed air supply device 224 Check valve 225 Safety valve 220A Air introduction pipe 226 Branch point 227 Valve (switching valve)
228 Valve (Switching valve)
229 Tank 300 Channel changing means 301 Connecting pipe 311 First valve 312 Second valve 313 Third valve

Claims (11)

When the ground is improved, the ground is excavated by the excavation head equipped at the tip of the rotating shaft, the rotating shaft is penetrated into the ground, and when penetrating, the fluid is sent from the ground through the supply pipe line arranged along the rotating shaft, In the ground improvement method of spraying the fluid from the discharge port provided in the excavation head toward the excavation soil,
As the fluid supply device, a pressure water supply device and a compressed air supply device are provided on the ground, and the compressed water and compressed air supplied from both supply devices are joined before being introduced to the inlet of the supply pipe line. Then, the ground improvement method is characterized in that it is fed to the excavation head through a supply pipe and sprayed from the discharge port toward the excavated soil. The ground improvement method according to claim 1,
By combining the air supply pipe extended from the compressed air supply apparatus with the water supply pipe extended from the pressurized water supply apparatus, the flow of compressed air is merged with the flow of compressed water, and the compressed air before the junction A ground improvement construction method comprising: a check valve for preventing a fluid flow from the merging point side and a safety valve for releasing a pressure higher than a specified pressure on an air supply pipe extending from a supply device. The ground improvement method according to claim 1,
The excavation head is provided with a spiral blade having an excavation claw at the lower end edge, a fluid injection box is provided on the back side in the rotation direction of the spiral blade, and the rotation direction of the spiral blade is directed to the injection box. The ground is provided with at least one of a discharge port that discharges fluid, a discharge port that discharges fluid backward, and a discharge port that discharges fluid outward in the rotational radial direction of the spiral blade Improvement method. The ground improvement method according to claim 3,
A discharge port that discharges fluid toward the front in the rotational direction of the spiral wing, a discharge port that discharges fluid toward the rear, and a fluid toward the outer side in the radial direction of rotation of the spiral wing to the jet box. A ground improvement method characterized by providing three types of discharge ports, the discharge port, and selectively opening one of the discharge ports to discharge the fluid and closing the other according to the conditions of the excavated ground. . A rotating shaft that is vertically supported and drilled into the ground with a drilling head equipped at the tip;
A drive device that moves up and down while rotating the rotating shaft;
A first supply line arranged along the rotation axis;
A discharge port that is provided in the excavation head and discharges the fluid that has been fed through the first supply pipe toward the excavation soil;
A pressurized water supply device and a compressed air supply device provided on the ground;
A water supply pipe for sending pressurized water supplied from the pressurized water supply device to an inlet of the first supply pipe;
An insertion port provided on the water supply pipe before the inlet of the first supply pipe line;
An air supply pipe for joining the compressed air supplied from the compressed air supply device to the insertion port;
A check valve that is provided on the air supply pipe and prevents a reverse flow of fluid from the insertion port side;
A safety valve that is provided on the air supply pipe upstream of the check valve and that releases a pressure higher than a specified pressure;
A ground improvement device characterized by comprising: The ground improvement device according to claim 5,
The excavation head is provided with a spiral blade having an excavation claw at the lower end edge, a fluid injection box is provided on the back side in the rotation direction of the spiral blade, and the injection box has a forward direction in the rotation direction of the spiral blade. One of a discharge port that discharges fluid toward the discharge port, a discharge port that discharges fluid toward the rear, and a discharge port that discharges fluid toward the outer side in the rotational radial direction of the spiral blade is provided. Ground improvement device. The ground improvement device according to claim 6,
A discharge port that discharges fluid toward the front in the rotational direction of the spiral wing, a discharge port that discharges fluid toward the rear, and a fluid toward the outer side in the radial direction of rotation of the spiral wing to the jet box. A ground improvement device characterized in that three types of discharge ports, the discharge ports, are provided so that only one of them can be selectively opened. The ground improvement device according to any one of claims 5 to 7,
An agitating blade provided at the tip of the rotating shaft and positioned above the excavation head;
A second supply line arranged along the rotation axis separately from the first supply line;
A stabilizer outlet for discharging the stabilizer sent from the ground through the second supply pipe into the excavated soil at the rotational height of the stirring blade;
A pressure supply device for stabilizing material provided on the ground;
A stabilizing material pumping pipe for introducing the stabilizing material pumped from the pumping supply device into an inlet of a second supply pipe line arranged along the rotation axis;
A flow path changing means for introducing the stabilizing material sent from the pressure feeding device of the stabilizing material into the inlet of the first supply pipe as necessary;
The ground improvement apparatus characterized by comprising. The ground improvement device according to claim 8,
The flow path changing means is
A communication pipe connecting the pressure feed pipe and the water feed pipe;
A first valve for opening and closing the connecting pipe;
A second valve that is closed to prevent back flow of fluid upstream of the connecting pipe connection point when the first valve is open, and more than the connecting pipe connection point; A third valve provided on the downstream side of the pressure feed pipe and controlled to open and close in conjunction with the first valve;
A ground improvement device characterized by comprising: It is the ground improvement apparatus of any one of Claims 5-9,
An agitating blade provided at the tip of the rotating shaft and positioned above the excavation head;
A second supply line arranged along the rotation axis separately from the first supply line;
A stabilizer outlet for discharging the stabilizer sent from the ground through the second supply pipe into the excavated soil at the rotational height of the stirring blade;
A pressure supply device for stabilizing material provided on the ground;
A stabilizing material pumping pipe for introducing the stabilizing material pumped from the pumping supply device into an inlet of a second supply pipe line arranged along the rotation axis;
An air inlet provided on the pumping pipe;
An air introduction pipe that introduces compressed air supplied from the compressed air supply means into an air introduction port on the pressure feed pipe, and mixes the compressed air into a stabilizer that is pumped in the pressure feed pipe;
The ground improvement apparatus characterized by comprising. The ground improvement device according to claim 10,
A branch point is provided on the air supply pipe downstream of the check valve, the air introduction pipe is branched from the branch point, and the introduction destination of the compressed air supplied through the air supply pipe is set on the water supply pipe. A ground improvement device provided with switching valve means for switching between an insertion port and an air introduction port on a pressure feed pipe.

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