JP7616772B2 - On-site construction method for foundation piles - Google Patents

Description

When constructing a concrete structure or a large, heavy concrete building such as an apartment building or a building on the ground, a large number of foundation piles of the required diameter and a specified length are driven into the ground at the construction site as foundation work to support the heavy structure or large building. This invention relates to a technology for constructing these foundation piles by excavating vertical holes using a horizontal hole boring machine used in underground pipe construction, reusing the generated waste soil, adding a solidifying material to form improved soil, and mixing and filling the drilled holes.

As shown in Patent Documents 1 and 2, conventional foundation pile driving work involves installing a PC impact machine or pile driver equipped with a long vertical leader of more than 10 m on the site, and using a PC pile driving method or pre-boring method to drive long foundation piles from above ground into the ground while applying impact vibrations until they reach the supporting layer, thereby constructing the foundation piles.
Also, when constructing cast-in-place piles, one method involves digging with a boring machine using a large crawler crane, filling the hole with a bentonite solution or the like, and then replacing it with concrete from below using a tremie pipe.

This conventional foundation pile installation method requires the safe installation of large, tall PC hammers, pile drivers, drilling machines, etc., at the site, and a large installation space must be secured for these. In addition, there is a risk that the PC hammers and pile drivers will tip over due to earthquakes or wind, destroying surrounding buildings, and they also generate large vibrations and noise at the construction site.

In addition, with conventional foundation pile installation methods, it was difficult to change the pile diameter or length on-site in response to changes in the properties of the ground below. Also, a large amount of excavated soil particles was discharged to the ground during ground excavation work, resulting in costs being incurred for subsequent disposal.

JP 2016-211225 A Japanese Patent Application Publication No. 08-144673

The problem to be solved by the present invention is to provide a new construction method for foundation piles which solves the following conventional problems and has the following advantages A to F.
(i) The pile diameter and length can be changed on-site in response to ground conditions and changes, enabling the construction of appropriate foundation piles.
(b) The excavated soil particles discharged to the ground are re-introduced as an improved soil by adding solidification material on-site, making effective use of the soil, reducing the amount of waste soil discharged and reducing the labor required for post-discharge soil processing.
C: Make it possible to prevent large vibrations and noise from occurring during the foundation pile driving process.
2) To significantly reduce the labor and workload required for transporting and using large PC impact machines, pile drivers, and drilling machines with long upward leaders that are necessary for conventional foundation pile work, to the site, as well as the labor and workload required for crane work to drive and hoist piles and steel materials on site.
E: The tunneling machines and other equipment used will be able to be transported in and out through narrow public roads, thereby realizing labor savings.
F: Eliminate the need for long secondary concrete products, steel materials, etc., and significantly reduce the work of transporting them in and out.

The configuration of the present invention that solves such problems is as follows:
1) A method for constructing foundation piles at a site where foundation piles for a building are to be driven, in which a closed tunneling machine is driven vertically into the ground at the site to excavate a hole of a specified diameter and depth, and then the excavated soil and solidification material are mixed and filled into the hole to construct a solidified foundation pile at the drilled hole position,
The tunneling machine has a partition wall at the bottom end of a vertical cylindrical outer shell, and has an excavation cutter section below the partition wall, and further has an earth discharge port for taking in excavated earth and sand, and inside the outer shell above the partition wall has a rotating device for rotating the cutter section and an earth discharge pipe equipped with an opening and closing valve in the middle for sending the earth discharged from the earth discharge port upward, and the diameter of the outer shell of the tunneling machine is the same as the diameter of the foundation pile to be constructed, and a plurality of steel pipes are prepared which have the same diameter as the rear end edge of the tunneling machine and the edges of the steel pipes connected as the lining body and can be freely connected to each other detachably with flanges, and the earth discharge pipes are arranged so as to be passed through the inside of the steel pipes and sent to the ground, and further the tunneling machine can be supported vertically on the ground at the site where concrete is poured, and the required number of steel pipes can be connected above the tunneling machine, a launching platform capable of removing the topmost steel pipe by releasing the flanges from the multiple tiers of steel pipes connected to the tunneling machine with flanges; a hydraulic jack device mounted on the launching platform and capable of vertically pushing the topmost steel pipe connected to the tunneling machine with flanges to generate a vertical thrust on the tunneling machine and the steel pipes, and pushing the topmost steel pipe connected to the tunneling machine with flanges upward to lift the tunneling machine and the steel pipes connected thereto to the launching platform on the ground; an improved body manufacturing device that mixes a prescribed ratio of solidification material with the waste soil transported from the tunneling machine to the ground via the soil discharge pipe and stored in a stock tank or with the waste soil generated at another site and transported; and an improved body pumping device that pumps the improved body thus produced into the inside of the soil discharge pipe exposed on the ground.
an excavation process in which, during excavation, the tunneling machine is held facing downward on the launching platform, a predetermined number of steel pipes are flange-connected above the tunneling machine, and the tunneling machine is operated while applying a vertical pressing force to the topmost steel pipe with the hydraulic jack device, and while the tunneling machine is excavating vertically, the required number of steel pipes are added upward on the launching platform, thereby lining the ground to the required depth required for the foundation piles;
A construction method 2 for on-site foundation piles, comprising: an improved body manufacturing process in which the excavation process uses the excavated soil discharged from the excavation pipe of the tunneling machine to the ground or the excavated soil from another site to mix a predetermined ratio of solidification material on the ground and produce an improved body with an improved body manufacturing device; an improved body filling and mixing process in which the improved body produced is pressure-fed into the excavation pipe exposed on the ground by an improved body pressure-feeding device, and the improved body is pressed through the excavation pipe from the cutter bulkhead at the tip of the tunneling machine underground, while the steel pipe connected to the tunneling machine with a flange is lifted with the hydraulic jack and mixed with the cutter part of the tunneling machine to uniformly fill the improved body in the drilled hole; a recovery process in which the tunneling machine and the steel pipe above it are lifted to the ground position of the starting platform by the hydraulic jack, the flange-connected steel pipe is separated, and the tunneling machine is recovered to the ground; and a solidification process in which the improved body stirred while the tunneling machine is recovered upward solidifies and adheres to the drilled hole wall with a predetermined outer diameter and a predetermined depth that reaches the supporting ground, completing a concrete foundation pile supported on the supporting ground. The method 3) for constructing foundation piles on site as described in 1) above is configured such that, as a flange for connecting the rear edge of the outer shell of the tunneling machine with the lower end edge of the steel pipe serving as a lining immediately above it and a flange for connecting the upper and lower end edges of the upper and lower steel pipes, an annular inner flange is provided that protrudes from the rear edge of the outer shell of the tunneling machine to the inside of the outer shell, and annular inner flanges are provided that protrude from the edges of the upper and lower ends of the steel pipe to the inside of the pipe, and the tunneling machine and the inner flanges that overlap above and below the opposing edges of the steel pipe above them, which are arranged in series in the same vertical direction, are connected to each other detachably with bolts and nuts at the launch pad. The launching platform is fixed to the ground at the site and holds the tunneling machine and the steel pipe connected thereto so that they are in the same vertical direction as the center of the foundation pile to be constructed, and the launching platform has a frame structure that holds the tunneling machine and the steel pipe so that the tunneling machine and the steel pipe can move up and down in the same vertical direction. The hydraulic jack device is structured so that a push wheel that can press the end of the steel pipe that is the topmost level is attached to the launching platform so that it can move up and down in the same vertical direction, and a plurality of double-pull hydraulic jacks are provided between the push wheel and the base of the launching platform installed on the ground, and the tips of the cylinder rods of the plurality of hydraulic jacks are attached to the push wheel, and the cylinder body side of the hydraulic jacks is connected to the launching platform. a hydraulic jack that pulls both ways is operated so that when the tunneling machine and the steel pipe are pushed down, the lower threaded portion of the suspension bolt is screwed into the fixing nut on the inner flange of the top steel pipe to connect the push ring and the top steel pipe, and the cylinder rod of the hydraulic jack that pulls both ways is operated to extend upward, thereby lifting the tunneling machine and the steel pipe connected thereto upward;
On the ground of the site, a vacuum pump that sucks the discharged soil to the ground side through the soil discharge pipe, a soil discharge storage tank that temporarily stores the discharged soil sent to the ground by the vacuum pump, a solidification material hopper that stores the solidification material, an improved body manufacturing device that produces the improved body by kneading the discharged soil in the soil discharge storage tank and the solidification material in the solidification material hopper at a predetermined ratio, an improved body pressure feeding device and its piping that feeds the improved body produced by the improved body manufacturing device into the soil discharge pipe of the tunneling machine, a launching platform that can vertically arrange the tunneling machine and multiple steel pipes relative to the ground above the foundation piles to be produced at the site, and that can vertically hold a propellant having opposing flanges detachably connected by bolts and can also move the propellant downward toward the ground or upward toward the ground, and a hydraulic jack device attached to the launching platform that can push down the top steel pipe of the propellant supported by the launching platform or lift it upward toward the ground side,
First, a tunneling machine with an outer diameter approximately the same as the pile opening of the foundation pile to be driven in the same vertical direction is placed on the launch platform, and multiple steel pipes with an outer diameter approximately the same as the outer diameter are placed above it. The vertical tunneling machine and the steel pipe above it are connected to each other with flanges, and then the hydraulic jack device attached to the launch platform is operated to apply a downward force to the uppermost push wheel by the hydraulic jack device to the tunneling machine and the multiple connected steel pipes. The tunneling machine then excavates the ground in the vertical direction with its cutter section, and the excavated soil and sand are discharged from the ground to the soil discharge port of the bulkhead. The soil is taken in from the tunnel and temporarily stored in the soil storage tank via the soil discharge pipe and the vacuum pump on the ground. When the tunneling machine excavates the steel pipes connected to it downwards by the length of several pipes, the necessary number of steel pipes are added to the upper end rim of the topmost steel pipe inserted into the ground of the launch pad as a lining so that they are on the same vertical line as the steel pipes pressed into the ground on the launch pad, and the steel pipes are connected to each other with flanges. After that, the topmost pipe end of the steel pipes added by the hydraulic jack device is pressed downward on the same vertical line with the pressure ring by the hydraulic jack device, while the tunneling machine is operated to excavate at the same time. This is repeated, and when the tunneling machine excavates to a predetermined depth where the ground strength is high, the operation of the hydraulic jack device and the tunneling machine is stopped, and the waste soil from the soil storage tank and the solidification material in the solidification material hopper are mixed in a predetermined ratio in the improved body manufacturing device to produce an improved body, and then the improved body that has been mixed is pumped into the soil discharge pipe exposed above ground by the improved body pumping device, and the improved body is ejected from the soil discharge port at the bottom while the tunneling machine is operated and stirred with its cutter section, and the topmost steel pipe on the starting platform is lifted upward by the hydraulic jack device, and the improved body is directed from the soil discharge port of the tunneling machine toward the face. and when the multiple steel pipes and the tunneling machine are moved to a launching platform on the ground, the flange connection at the launching platform is released , the steel pipes and the tunneling machine are removed from the launching platform, and the tunneling machine and the upper steel pipes are returned to the ground and can be reused. The improved body filled and mixed in the drilled hole is solidified to become a foundation pile having the advantages of both a high-strength support pile with a long excavation depth that reaches the supporting layer with the diameter of the tunneling machine, and a friction pile in a dense state with the surrounding ground, and further, a foundation pile with its base secured to the ground can be constructed. 5) A method for constructing foundation piles on site as described in 3) above. The soil used for the improved body is the soil excavated by the tunneling machine and sent to the ground by its soil discharge pipe, eliminating the need to transport the soil to a treatment plant. 1)
4) The on-site construction method of foundation piles is described in any one of the following.

According to the present invention, a tunnel boring machine used in tunnel jacking method is used to drill holes for foundation piles in the ground at the site, and multiple stages of steel pipes that follow it above are flange-connected to a launch pad on the ground. The boring machine is set vertically from the launch pad and pushed down by a hydraulic cylinder while operating, and a hole is excavated in the ground with the cutter at the bottom of the boring machine. Therefore, the method of the present invention makes it possible to carry out work in narrow spaces, and vibrations and noises detected on the ground are greatly reduced. The soil discharged from the face is taken into the soil discharge pipe through the soil discharge valve inside the boring machine from the soil discharge port in the bulkhead at the bottom of the boring machine, and is transported through the steel pipe to a soil discharge container tank on the ground side.

In addition, whether the tunneling machine has reached a layer of soil with high supporting strength can be accurately confirmed by the rotational load on the cutter section, or by measuring devices such as an excavation depth gauge, or by the length of the tunneling machine and the number of steel pipes driven in, and the tunneling machine can be made to reach the supporting layer to the required depth by adding the required number of steel pipes to the tunneling machine with flanges. In this invention, hydraulic jacks are used for the downward pushing and lifting of the tunneling machine and steel pipes, so no noise or vibration is generated. In addition, since no expensive machinery is used, it is easy to work in narrow areas.

When the tunneling machine reaches the supporting layer at a specified depth, the tunneling machine and steel pipe are stopped, and the discharged soil that has been sent to the ground side is mixed in a specified ratio with the solidification material from the solidification material hopper installed on the ground side in a mixer. The improved soil produced by mixing is pressure-fed by the pressure pump into the inside of the soil discharge pipe exposed above ground. If the discharged soil generated during excavation is used, it is mixed with the solidification material on the ground and returned to the drilling hole, so most of the discharged soil volume is reused and reduced.

The pressurized improvement body passes through the drainage pipe and is discharged to the face from the drainage port in the bulkhead at the bottom of the tunneling machine, allowing the face space to be pressurized and filled with the improvement body.

Furthermore, when the tunneling machine is operated in this state and the rotating blade of the cutter section at the bottom is rotated, this cutter section can remix and stir the improvement material filled into the face, and the injection pressure during insertion allows it to thoroughly fill any irregularities or cracks in the pile hole wall. While the rotating blade of the cutter section is rotating, the steel pipes connected by flanges and the entire tunneling machine below it are slowly raised above ground by a hydraulic jack device on the ground. This ensures that the concrete strength of the hardened foundation pile is high and of good quality, and the pile diameter and depth can also be accurately constructed.

As the tunneling machine rises, the improvement material from the soil discharge port is gradually ejected from above while being stirred by the cutter section, filling the pile hole evenly, and the stirring force and injection pressure of the improvement material allow it to penetrate well into the hole wall. The tunneling machine and the steel pipe above it are then lifted by a hydraulic jack device on a launch pad on the ground. With this method, the tunneling machine and the steel pipe above it are advanced into the ground and lifted to the launch pad using the digging force of the tunneling machine and the propulsion and lifting forces of the hydraulic jack device, so no impact or vibration noises are generated and there is almost no pollution caused by these.

Through this process, the improved material is thoroughly mixed with the excavated soil and sand, and is pressurized, mixed, and filled thoroughly inside the pile hole, allowing it to solidify. Once the tunneling machine and steel pipe are lifted up to a launch pad on the ground, the flange connection between the tunneling machine and the upper steel pipe is released and separated, or they are moved without being separated to the launch pad for the driving position of the next foundation pile.

When the improvement material is filled into the drilled hole and solidified, the solidified material in the center of the drilled space and the improvement material on the periphery of the pile hole adhere to the cracks and unevenness in the drilled hole wall due to the filling pressure and stirring by the cutter, and the solidified outer periphery solidified material spreads out like branches to become an integrated foundation pile. A foundation pile with a pile diameter of the outer shell of the tunneling machine and which is strongly integrated with the surrounding ground is created.

The on-site foundation pile construction method of the present invention provides the following advantages (1) to (13).
(1) It is a construction technique that allows all construction machinery to be miniaturized, thereby achieving the same high strength structures and high quality as those made by larger machinery.
(2) Equipment can be brought in and taken out even on narrow public roads, and compactness can be achieved.
(3) This construction method produces very little noise and vibration.
(4) Piles made of steel or concrete prefabricated products are not used.
(5) The weight of the tunneling machine itself (outer diameter φ1000mm for the tunneling machine tip is about 2.5t, and for φ800mm it is about 2t) means that a mobile crane (10T hoisting) is required to hoist the tunneling machine vertically once and set it up, but after that a vehicle of about a 4T truck (hoisting truck) can be used to hoist the steel pipe, which makes it possible to reduce the amount of labor required for construction machinery.
(6) It is possible to respond flexibly to changes in the ground at the site, since it is possible to freely change the drilling diameter (by replacing the tunneling machine) to ensure the bearing capacity for the weight of the building structure above and to changes in the ground. This is also an issue or concern that has been a problem with conventional foundation piles, and this construction method is highly adaptable to changes in the ground, the pile length to the supporting layer, and the pile cross-sectional area.
(7) When the tunneling machine is pulled up, the improvement body is filled into the tunnel face, which strengthens the adhesion between the hole wall and the surrounding ground and increases the surrounding friction force (utilizing the advantages of both support piles and friction piles).
(8) The excavated soil and sand are temporarily stored in a storage tank on the ground surface, and then later mixed and stirred with a cement-based material (solidification material) using a small mixer to convert it into an improved mass with high plastic fluidity. This improved mass is then refilled into the ground as pile material to construct improved piles. This construction method significantly reduces the amount of soil and sand that is ultimately disposed of, making it a construction technology that greatly reduces the environmental burden.
(9) When the tunneling machine performs preliminary excavation by boring a hole in the ground, a reusable flange-fastened steel pipe is used for the following pipe, and while filling the improvement body into the lowest tunneling machine face, the steel pipe and the tunneling machine are simultaneously pulled up to the ground by the amount of pressure filling to form a pile. The tunneling machine and all of the steel pipes can be recovered to the ground, making it a cost-reducing construction method that can be reused for the next construction project.
(10) The soil discharge system during excavation uses the tunneling machine soil discharge valve (air + rubber valve) used when constructing a horizontal pipeline inside the vertical tunneling machine's subsequent body pipe, and pulls the discharged soil up to the ground surface with a normal suction soil discharge device (vacuum force generator). In this case, since the steel pipe is unmanned, it is necessary to adjust the amount of air supplied, so the air supply steel pipe and soil discharge pipe are installed in parallel inside the steel pipe.
In addition, an openable and closable valve is installed on the ground surface to adjust the amount of air supplied.
(11) Add a cement-based solidification material to the soil discharged during excavation (a mixture of natural soil and muddy water at the face). In this case, a mixing and stirring device is used to form a fluid improved mass, which is then back-injected into the drainage valve of the tunneling machine using a pressure pump to solidify the face. At this time, the cutter part of the tunneling machine is rotated to further mix the material, allowing the construction of highly uniform piles.
(12) The construction method of the present invention clearly defines the shape and dimensions of the excavation cross section and the reinjection cross section using a tunneling machine and following steel pipes, etc., and the quality of the improved soil to be filled can be controlled using test pieces each time.
(13) Because a vertical tunneling machine is used, tunneling is carried out with the face pressurized, which means that the impact on the surrounding ground (loosening of the ground, etc.) is very small, and damage and impact to adjacent houses, etc. can be kept to a minimum.

FIG. 1 is a plan view showing the on-site setting state of each device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing an improved body manufacturing apparatus and an improved body pumping apparatus according to the embodiment. FIG. 3 is a perspective view showing the structure of the launch pad of the embodiment. FIG. 4 is a front view of the launch pad of the embodiment. FIG. 5 is a side view of the launch pad of the embodiment. FIG. 6 is a front view showing the hydraulic jack device of the embodiment. FIG. 7 is a side view of the hydraulic jack apparatus according to the embodiment. FIG. 8 is a front view showing the state in which three stages of steel pipes are connected by flanges on the launch pad of the embodiment. FIG. 9 is a front view showing the state in which the lowest steel pipe of the launch pad of the embodiment has been buried in the ground. FIG. 10 is a plan view showing a pressure ring used in the embodiment. FIG. 11 is a front view showing the guide rail of the starting platform of the embodiment. FIG. 12 is a plan view taken along the line A in FIG. FIG. 13 is a plan view taken along the line B in FIG. FIG. 14 is an explanatory diagram of the internal structure of the tunneling machine according to the embodiment. FIG. 15 is an explanatory diagram showing the tunneling machine of the embodiment and the state in which the steel pipe above it is lifted from the launch pad. FIG. 16 is an explanatory diagram showing the connected state of the inner flange that connects the steel pipes of the embodiment. FIG. 17 is an explanatory diagram showing a structure for connecting a press ring and a steel pipe in the embodiment. FIG. 18 is an explanatory diagram showing the construction process of the on-site foundation pile construction method of the embodiment. FIG. 19 is an explanatory diagram showing the construction process of the on-site foundation pile construction method of the embodiment.

The tunneling machine of the present invention can be the same as the tunneling machine used in the tunnel jacking method.

The present invention will be explained using the examples shown in Figures 1 to 19.

(Explanation of symbols in the embodiment)
In the figure, G indicates the on-site construction method for foundation piles of the embodiment. 1 is a launching platform installed on the ground of the planned foundation pile, 10 is a ground frame that installs the launching platform on the ground, 11 is a vertical frame fixed to the ground frame, 12 is a horizontal frame that connects multiple vertical frames, 13 is an anchor member driven into the ground to anchor the ground frame to the ground, 14 is a cylindrical guide installed in the center of the ground frame for the tunneling machine 3 and steel pipe 4 to enter the ground vertically, 15 is a jack to prevent the guide from sinking, and 16 is a guide for the up and down movement of the tunneling machine 3 and steel pipe 4 attached to the upper horizontal frame 12. Reference numeral 17 denotes a disk-shaped push wheel which transmits propulsion and lifting force to the steel pipe, 171 denotes a guide protrusion which engages with the guide rail 16 which brakes the up and down movement of the push wheel, 2 denotes a hydraulic jack device attached to the starting platform 1, 20 denotes a plurality of hydraulic jacks dedicated to pulling which make up the hydraulic jack device, 21 denotes a cylinder rod of the hydraulic jack, 22 denotes a cylinder body of the hydraulic jack, 220 denotes a link section which connects the tip of the cylinder rod 21 to the push wheel 17, and the cylinder body 22 is connected to the ground frame. 23 is a suspension bolt attached to the push wheel side connecting the push wheel 17 and the top steel pipe, 24 is a fixing nut provided on the inner flange of the steel pipe that screws onto the lower end of the suspension bolt, 3 is a tunneling machine, 30 is the outer shell of the tunneling machine, 31 is an inner flange provided at the mouth edge at the upper end of the outer shell, 32 is a plurality of bolt holes provided in the flange, 33 is a partition wall at the lower end of the tunneling machine 3, 34 is a cutter section using a rotating blade that revolves around its axis and is provided on the outside center of the partition wall, 341 is the rotation axis of the cutter section, and 342 is a shaft provided within the outer shell 30 above the partition wall 33. 3 is a rotary device for the cutter section 34 attached to the wall, 35 is an earth discharge port provided in the center of the bulkhead, 36 is an earth discharge pipe connected to the earth discharge port, 37 is a rubber valve provided midway through the earth discharge pipe 36 and an earth discharge valve for opening and closing using air, 38 is an air supply steel pipe that takes in naturally aspirated air from the ground, 39 is an inner flange provided at the rear edge of the outer shell 30, 391 is a bolt hole provided in the inner flange 31 of the outer shell 30, 392 is a connecting bolt that connects the bolt hole to the bolt hole 42 of the inner flange 41 at the lower end of the steel pipe 4, 4 is a steel pipe with the same diameter as the outer shell 30, 41 is The steel pipe 4 has inner flanges provided on the upper and lower end edges, 42 has bolt holes provided in the flanges, 43 has connecting bolts connecting the bolt holes 42 in the inner flanges 41 on the upper and lower edges of the steel pipe 4, 50 has a vacuum pump connected to a discharge soil pipe arranged on the ground at the site and sucks up the discharge soil sent to the discharge soil pipe 36 by negative pressure, 51 has a discharge soil storage tank that stores the discharge soil sent to the ground through the discharge soil pipe, 52 has a solidification material hopper that stores the solidification material, and 53 has a screw that mixes the discharged soil from the discharge soil storage tank and the solidification material stored in the solidification material hopper in a predetermined ratio. The improved body is produced by mixing in a kneading machine in an improved body manufacturing device, 54 is an improved body pressure delivery pump that pressure-feeds the improved body produced in the improved body manufacturing device into the soil discharge pipe 36 placed on the ground of the excavator via improved body injection piping 540, 55 is a crawler crane that grabs the launch platform 1 with the tip of the crane arm and moves the launch platform 1, 56 is an air tank, 57 is an air compressor, 59 is a hydraulic unit that outputs hydraulic pressure, 60 is an additive plant that stores other additives, and 61 is an additive pump that outputs additives from the additive plant.

(Construction process/work procedure)
The work will be explained below with reference to the construction drawings in Figures 18 and 19.
1: A small pit is excavated at the pile position on the ground surface, and a guide 14, which is the pit entrance hardware (entrance), and a ground frame 10 for the launch pad 1 are installed (see Figures 5 and 18).
2: Install a vertical launch pad 1 on top of the ground frame 10 at the entrance (see Figures 3 to 5 and 18).
3: Fix the tunneling machine 3 and the upper steel pipe 4 inside the launch pad 1 (see Figures 5, 6, 7, 8, 9 and 18).
4: An excavation additive plant 60 (mud plant), waste soil storage tank 51, etc. are installed outside the mine.
5: Using the remote control panel, the hydraulic jack device 2 inside the vertical launch platform 1 is used to rotate the rotary blade of the cutter section 34 of the tunneling machine 3 while performing excavation work downward (see Figures 5 to 9 and 18).
6: At the same time, the hydraulic jack (pull jack) 20 is used to push the tunneling machine 3 into the ground (tunneling speed is approximately 2 cm/min to 10 cm/min) (see Figures 5 to 9 and 18).
7: After the tunneling machine 3 has been inserted into the ground, a steel pipe (temporarily about 80 cm to 100 cm long) is connected to the top of the tunneling machine 3 (repeat steps 6 to 9, see FIG. 18).
8: Once the pipe connection work is completed, re-excavation will be carried out (see Figures 6-9 and 18).
9: Once the excavation of the No. 1 steel pipe length is completed, change the setup and connect the No. 2 steel pipe (see Figures 6 to 9, 18, and 19).
10: Repeat the process of adding steel pipes (see Figures 6 to 9, 18, and 19)
11: After excavation has been completed down to the solid supporting ground SR, the waste soil stored in the waste soil storage tank 51 installed on the ground surface is mixed and mixed with the improved soil manufacturing device 53, which mixes and kneads the solidification material in the solidification material hopper 52, such as a cement-based material, to create a fluidized improved soil (see Figures 1, 2, and 19).
12: The improved body is pumped from the ground surface to the tunneling face by the improvement body pressure delivery pump 54, and the excavator 3's soil discharge pipe 36 is reused as a transport pipe to pump the improved body, filling it into the drilled hole (see Figure 19).
13: Depending on the lifting speed of the hydraulic jack device 2 of the tunneling machine 3, the improvement body is continuously pressurized and filled into the returned hole wall by the improvement body pressure delivery pump 54 (see Figure 19).
14: As soon as each steel pipe has been filled, it is pulled up using the hydraulic jack device 2, and the steel pipes 4 protruding from the launch pad 1 on the ground surface are removed one by one, forming a continuous cast-in-place pile from the bottom end of the excavation (see Figure 19).
15: Repeat steps 11 to 13 above to pull the rear of the tunneling machine 3 up to the launch pad 1 on the ground surface (see Figure 19).
16: After removing the tunneling machine 3, the vertical launch platform 1 is dismantled and removed.
17: Finally, the tunnel head hardware installed on the surface is removed and one unreinforced cast-in-place pile foundation is completed.

As such, construction is possible at the site where the foundation piles are to be constructed as long as a low launch platform and hydraulic jack equipment can be installed, making construction easy and quick even in small sites. It is safe and produces little noise and vibration, resulting in less pollution.

In this invention, multiple foundation piles can be constructed on-site in parallel using multiple launch platforms and hydraulic jack devices, making it easy to work with and to change the pile diameter.

G On-site construction method for foundation piles according to an embodiment SR Supporting ground 1 Launch pad 10 Ground frame 11 Vertical frame 12 Horizontal frame 13 Anchor member 14 Guide 15 Anti-subsidence jack 16 Guide rail 17 Push wheel 171 Guide protrusion 2 Hydraulic jack device 20 Hydraulic jack for pulling only 21 Cylinder rod 22 Cylinder body 220 Link section 23 Suspension bolt 24 Fixing nut 3 Tunneling machine 30 Outer shell 31 Inner flange 32 Bolt hole 33 Partition wall 34 Cutter section 341 Rotating shaft 342 Rotating device 35 Soil discharge port 36 Soil discharge pipe 37 Soil discharge valve 38 Air supply steel pipe 39 Inner flange 391 Bolt hole 392 Connecting bolt 4 Steel pipe 41 Inner flange 42 Bolt hole 43 Connecting bolt 50 Vacuum pump 51 Soil discharge storage tank 52 Solidification material hopper 53 Improved material manufacturing device 54 Improved material pressure delivery pump 540 Improved material injection piping 55 Crawler crane 56 Air tank 57 Air compressor 59 Hydraulic unit 60 Additive plant 61 Additive pump

Claims (5)

A method for constructing foundation piles on site, in which a closed tunneling machine is driven vertically into the ground at the site to drive foundation piles for a building, to excavate a hole of a specified diameter and depth, and then the excavated soil and solidification material are mixed and filled into the hole to construct a solidified foundation pile at the drilled hole position,
The tunneling machine has a partition wall at the bottom end of a vertical cylindrical outer shell, and has an excavation cutter section below the partition wall, and further has an earth discharge port for taking in excavated earth and sand, and inside the outer shell above the partition wall has a rotating device for rotating the cutter section and an earth discharge pipe equipped with an opening and closing valve in the middle for sending the earth discharged from the earth discharge port upward, and the diameter of the outer shell of the tunneling machine is the same as the diameter of the foundation pile to be constructed, and a plurality of steel pipes are prepared which have the same diameter as the rear end edge of the tunneling machine and the edges of the steel pipes connected as the lining body and can be freely connected to each other detachably with flanges, and the earth discharge pipes are arranged so as to be passed through the inside of the steel pipes and sent to the ground, and further the tunneling machine can be supported vertically on the ground at the site where concrete is poured, and the required number of steel pipes can be connected above the tunneling machine, a launching platform capable of removing the topmost steel pipe by releasing the flanges from the multiple tiers of steel pipes connected to the tunneling machine with flanges; a hydraulic jack device mounted on the launching platform and capable of vertically pushing the topmost steel pipe connected to the tunneling machine with flanges to generate a vertical thrust on the tunneling machine and the steel pipes, and pushing the topmost steel pipe connected to the tunneling machine with flanges upward to lift the tunneling machine and the steel pipes connected thereto to the launching platform on the ground; an improved body manufacturing device that mixes a prescribed ratio of solidification material with the waste soil transported from the tunneling machine to the ground via the soil discharge pipe and stored in a stock tank or with the waste soil generated at another site and transported; and an improved body pumping device that pumps the improved body thus produced into the inside of the soil discharge pipe exposed on the ground.
an excavation process in which, during excavation, the tunneling machine is held facing downward on the launching platform, a predetermined number of steel pipes are flange-connected above the tunneling machine, and the tunneling machine is operated while applying a vertical pressing force to the topmost steel pipe with the hydraulic jack device, and while the tunneling machine is excavating vertically, the required number of steel pipes are added upward on the launching platform, thereby lining the ground to the required depth required for the foundation piles;
This on-site construction method for foundation piles comprises the steps of: an improved body manufacturing process in which the excavation process uses the waste soil discharged to the ground from the soil discharge pipe of the tunneling machine in the excavation process, and a predetermined ratio of solidification material is mixed on the ground with the improved body manufacturing device to produce an improved body; an improved body filling and mixing process in which the improved body prepared is pressure-fed into the tube of the soil discharge pipe exposed to the ground by an improved body pressure-feeding device, and the improved body is pressed through the soil discharge pipe into the drilled hole from the cutter partition at the tip of the tunneling machine underground while the steel pipe connected to the flange of the tunneling machine is lifted by the hydraulic jack while being stirred by the cutter part of the tunneling machine, thereby filling the drilled hole evenly with the improved body; a recovery process in which the tunneling machine and the steel pipe above it are lifted to the ground position of the launch pad by the hydraulic jack, the flange-connected steel pipe is separated, and the tunneling machine is recovered to the ground; and a solidification process in which the improved body stirred while the tunneling machine is recovered upward solidifies and adheres to the drilled hole wall with a predetermined outer diameter and a predetermined depth that reaches the supporting ground, completing a concrete on-site foundation pile supported by the supporting ground. The on-site construction method for foundation piles according to claim 1, in which an annular inner flange is provided that protrudes from the rear edge of the outer shell of the tunneling machine to the inside of the outer shell as a flange that connects the rear edge of the outer shell of the tunneling machine and the lower end edge of the steel pipe serving as a lining directly above it, and an annular inner flange is provided that protrudes from the edges of the upper and lower ends of the steel pipe to the inside of the pipe, and the inner flanges that overlap above and below the opposing edges of the tunneling machine and the steel pipe above it, which are arranged in series in the same vertical direction, are connected to each other detachably with bolts and nuts at the launch pad. The launch platform is fixed to the ground at the site and holds the tunneling machine and the steel pipe connected thereto so that they are in the same vertical direction as the center of the foundation pile to be constructed, and the launch platform has a frame structure that holds the tunneling machine and the steel pipe so that the tunneling machine and the steel pipe can move up and down in the same vertical direction. The hydraulic jack device is structured so that a push wheel that can press the end of the steel pipe that is the topmost level is attached to the launch platform so that it can move up and down in the same vertical direction, and a plurality of double-pull hydraulic jacks are provided between the push wheel and the base of the launch platform that is installed on the ground, and the tips of the cylinder rods of the plurality of hydraulic jacks are attached to the push wheel, and the cylinder body side of the hydraulic jacks is attached to the 3. A method for on-site construction of foundation piles as described in claim 2, wherein the structure is such that the hydraulic jack is attached to the base of a starting platform, a fixing nut is further provided on the inner flange of the upper edge of the topmost steel pipe, and the upper part of a suspension bolt that can be screwed into the fixing nut can be engaged with the pressure ring, and when the tunneling machine and steel pipe are pushed down, the pressure ring abuts against the upper edge of the topmost steel pipe to operate the double-pull hydraulic jack in a downward direction, and when the tunneling machine and steel pipe are lifted, the lower threaded portion of the suspension bolt screws into the fixing nut on the inner flange of the topmost steel pipe to connect the pressure ring and the topmost steel pipe, and the cylinder rod of the double-pull hydraulic jack is operated to extend upward, thereby lifting the tunneling machine and the steel pipe connected above it upward. In the on-site construction method of foundation piles according to claim 3 ,
On the ground of the site, a vacuum pump that sucks the discharged soil to the ground side through the soil discharge pipe, a soil discharge storage tank that temporarily stores the discharged soil sent to the ground by the vacuum pump, a solidification material hopper that stores the solidification material, an improved body manufacturing device that produces the improved body by kneading the discharged soil in the soil discharge storage tank and the solidification material in the solidification material hopper at a predetermined ratio, an improved body pressure feeding device and its piping that feeds the improved body produced by the improved body manufacturing device into the soil discharge pipe of the tunneling machine, a launching platform that can vertically arrange the tunneling machine and multiple steel pipes relative to the ground above the foundation piles to be produced at the site, and that can vertically hold a propellant having opposing flanges detachably connected by bolts and can also move the propellant downward toward the ground or upward toward the ground, and a hydraulic jack device attached to the launching platform that can push down the top steel pipe of the propellant supported by the launching platform or lift it upward toward the ground side,
First, a tunneling machine with an outer diameter approximately the same as the pile mouth of the foundation pile to be driven in the same vertical direction is placed on the starting platform, and multiple steel pipes with an outer diameter approximately the same as the outer diameter are placed above it. The vertical tunneling machine and the steel pipe above it are connected to each other with flanges, and then the hydraulic jack device attached to the starting platform is operated to apply a downward force to the uppermost push wheel by the hydraulic jack device to the tunneling machine and the multiple connected steel pipes. By operating the rotating device of the tunneling machine, the tunneling machine excavates the ground in the vertical direction with its cutter part, and the excavated soil and sand are removed from the ground by the soil removal device of the bulkhead. The soil is taken in from the opening and temporarily stored in the soil storage tank via the soil discharge pipe and the vacuum pump on the ground, and when the tunneling machine excavates the steel pipe connected to it downward by the length of several pipes, the necessary number of steel pipes are added to the upper end lip of the topmost steel pipe inserted into the ground of the launching platform as a lining so that they are on the same vertical line as the steel pipe pressed into the ground on the launching platform, and the steel pipes are connected to each other with flanges, and then the topmost pipe end of the steel pipe added by the hydraulic jack device is pressed downward on the same vertical line with the pressure ring by the hydraulic jack device while simultaneously operating the tunneling machine to excavate. This is repeated, and when the tunneling machine is driven to a predetermined depth where the ground strength is high, the operation of the hydraulic jack device and the tunneling machine is stopped, and the soil discharged from the soil discharge storage tank and the solidification material in the solidification material hopper are mixed in a predetermined ratio in an improved body manufacturing device to produce an improved body, and then the improved body that has been mixed is pumped into the soil discharge pipe exposed above ground by the improved body pumping device, and the improved body is ejected from the soil discharge port at the lower end while the tunneling machine is operated and stirred with its cutter section, and the topmost steel pipe on the starting platform is lifted upward by the hydraulic jack device, and the improved body is directed from the soil discharge port of the tunneling machine to the face. a flange-connected tunneling machine and steel pipe are raised while the improved material is ejected and mixed into the drilled hole, filling and mixing the drilled hole; when the multiple steel pipes and the tunneling machine have moved to a launching platform on the ground, the flange connection at the launching platform is released, the steel pipes and the tunneling machine are removed from the launching platform, and the tunneling machine and the upper steel pipes are recovered to the ground and can be reused; and the improved material filled and mixed into the drilled hole solidifies to become a foundation pile having the advantages of both a high-strength support pile with a length of excavation depth that reaches the supporting layer with the diameter of the tunneling machine and a friction pile that is dense with the surrounding ground, and which also allows the construction of a foundation pile with its base secured to the ground. The on-site foundation pile construction method according to any one of claims 1 to 4, in which the soil used for the improved body is excavated by the tunneling machine and sent to the surface through the soil discharge pipe, eliminating the need to transport the soil to a treatment plant.

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