Self-boring hole type monitor device and ground improvement method using the same

Abstract

To provide a self-drilling monitor capable of sealing an excavation hole water discharge opening using a simple method even with a small diameter and a ground improvement method using the same.SOLUTION: A valve 4 is arranged on an excavation hole water discharge opening 32 of a self-drilling monitor. The valve 4 comprises: a valve body 4a; a valve seat 4b arranged below the valve body 4a; a compression coil spring 4c energizing the valve body 4a downward; and a limitation member 5 limiting downward movement of the valve body 4a to prevent its abutment to the valve seat 4b. The limitation member 5 has a rod-like member 6 and a rod-receiving member 7, wherein the rod-receiving member 7 is configured as a fragile part to bend or rupture when water pressure exceeding the water pressure upon drilling acts on the valve body 4a. And, the valve body 4a is to abut on the valve seat 4b through release of limit by bending or rupturing of the rod-receiving member 7. This allows the excavation hole water discharge opening 32 to be sealed by making the water pressure exceeding the water pressure upon drilling act on the valve body 4a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a self-boring type monitor device used in a high-pressure jet mixing method or the like, and a ground improvement method using the same. More specifically, the present invention relates to a self-boring type monitor device of a type that combines a boring water flow path and a compressed air flow path, and a ground improvement method using the same.

Background Art

[0002] As a prior art of a self-boring type monitor device of a type that combines a boring water flow path and a compressed air flow path, there is Patent Document 1 previously filed by the present inventor. In the self-boring type monitor device described in this document, a porous surface with a plurality of holes opened at the boring water discharge port is provided. When switching from the boring process to the ground improvement process, a plurality of steel balls are introduced from the upper part of the rod (i.e., the ground surface) to block each hole of this porous surface, thereby closing the boring water discharge port.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art described in Patent Document 1, since a plurality of steel balls are introduced from the upper part of the rod (i.e., the ground surface) through the common flow path of the boring water flow path and the compressed air flow path to block the boring water discharge port, the diameter of the rod has to be relatively large, and there is a problem that it is not suitable for a small-diameter rod.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a self-boring type monitor device that can be applied to a small-diameter rod regardless of the diameter of the rod, and a ground improvement method using the same.

Means for Solving the Problems

[0006] The self-boring type monitoring device of the present invention is a self-boring type monitoring device including a boring water discharge port, a hardening material injection nozzle, a compressed air injection nozzle surrounding the hardening material injection nozzle, a first flow path that is a common flow path for boring water and compressed air, a second flow path for the hardening material, a third flow path connecting the first flow path and the boring water discharge port, a fourth flow path connecting the first flow path and the compressed air injection nozzle, and a valve for opening and closing the boring water discharge port, wherein the valve includes a valve body, a valve seat provided below the valve body, spring means for biasing the valve body downward, and regulating means for restricting the downward movement of the valve body and preventing contact with the valve seat, characterized in that the regulating means is configured to be released from regulation when a water pressure exceeding the water pressure during boring acts on the valve body.

[0007] According to the self-boring type monitoring device of the present invention, under the water pressure during boring, the contact (seating) of the valve body with the valve seat is restricted by the regulating means, and the valve maintains an open state, so that the boring process can be carried out without problems. On the other hand, by applying a water pressure exceeding the water pressure during boring to the valve body, the regulation by the regulating means is released, the valve body comes into contact (seats) with the valve seat, and the valve is closed. Therefore, by increasing the flow rate of the boring water supplied to the first flow path or the like to increase the water pressure acting on the valve body, the boring water discharge port can be blocked. Thus, it is not necessary to input steel balls from the ground through a rod as in the prior art of Patent Document 1, and it can also be applied to a small-diameter rod.

[0008] In the self-boring type monitoring device of the present invention, as one of its preferred embodiments, at least a part of the regulating means is configured as a fragile part that bends or breaks when a water pressure exceeding the water pressure during boring acts on the valve body, and the regulation of the regulating means can be released by the bending or breaking of the fragile part.

[0009] Also, as one of the preferred embodiments in that case, the restricting means includes a lateral member extending horizontally so as to cross a vertical flow path from the valve body to the hole drilling water discharge port, and a vertical member extending upward from the lateral member toward the valve body, and the lateral member can be configured as the vulnerable part.

[0010] Furthermore, in the self-drilling type monitor device of the present invention, as one of the preferred embodiments, the compressed air injection nozzle may be provided with a sealing member that is released from sealing when a pressure exceeding the water pressure during hole drilling acts thereon.

[0011] By sealing the compressed air injection nozzle with such a sealing member, even when hole drilling water is supplied to the first flow path during hole drilling, it is possible to prevent the hole drilling water from leaking out of the compressed air injection nozzle. And after the hole drilling process is completed, since the sealing can be released by applying a water pressure exceeding the water pressure during hole drilling to the sealing member, the original function as a compressed air injection nozzle can be exerted thereafter.

[0012] Next, the ground improvement method of the present invention is a ground improvement method using the above-described self-drilling type monitor device, a hole drilling step of supplying hole drilling water into the first flow path, discharging the hole drilling water from the hole drilling water discharge port, and rotating the monitor device to drill a hole to a predetermined depth, a valve closing step of increasing the water pressure of the hole drilling water to release the restriction of the restricting means and closing the valve, a ground improvement step of improving the surrounding ground by supplying compressed air and a hardening material into the first and second flow paths respectively while pulling up the monitor device while rotating it, and injecting the compressed air and the hardening material from the compressed air injection nozzle and the hardening material injection nozzle respectively, characterized by including.

[0013] According to the ground improvement method of the present invention, in the drilling process, the contact (seating) of the valve body with the valve seat is restricted by the restricting means, and the valve maintains an open state, so that the drilling process can be carried out without problems. On the other hand, by applying a water pressure exceeding the water pressure during drilling to the valve body, the restriction by the restricting means is released, the valve body contacts (seats) the valve seat, and the valve is closed. Therefore, after the drilling process is completed, the water pressure acting on the valve body is increased, for example, by increasing the flow rate of the drilling water supplied to the first flow path, whereby the drilling water discharge port can be blocked. Thus, it is not necessary to throw in steel balls from the ground surface through a rod as in the prior art of Patent Document 1, and it can also be applied to ground improvement using a small-diameter rod.

[0014] Moreover, the ground improvement method of the present invention is a ground improvement method using the above-described self-drilling type monitor device, a drilling process of supplying drilling water into the first flow path, discharging the drilling water from the drilling water discharge port, and turning the monitor device to drill to a predetermined depth, a valve closing process of increasing the water pressure of the drilling water to release the restriction of the restricting means and closing the valve, a sealing release process of releasing the sealing of the compressed air injection nozzle by the sealing member by the increased water pressure of the drilling water, a ground improvement process of injecting compressed air and a hardening material from the compressed air injection nozzle and the hardening material injection nozzle, respectively, while pulling up the monitor device while turning it, and supplying compressed air and a hardening material into the first and second flow paths, respectively, to improve the surrounding ground, characterized by including.

[0015] According to the ground improvement method of the present invention, by sealing the compressed air injection nozzle with a sealing member, it is possible to prevent the drilling water from leaking from the compressed air injection nozzle even when the drilling water is supplied to the first flow path during drilling. And after the drilling process is completed, the sealing can be released by applying a water pressure exceeding the water pressure during drilling to the sealing member, so that the original function as a compressed air injection nozzle can be exhibited thereafter.

[0016] In the ground improvement method of the present invention, as one of its preferred embodiments, in the seal release step, drilling water is supplied into the first flow path and compressed air is supplied into the second flow path, and while injecting compressed air from the hardening material injection nozzle, the seal of the sealing member may be released by the water pressure of the drilling water supplied into the first flow path.

[0017] By supplying drilling water into the first flow path and compressed air into the second flow path in this way, and releasing the seal of the compressed air injection nozzle with the water pressure of the drilling water while injecting compressed air from the hardening material injection nozzle, it is possible to prevent the drilling water from flowing back into the monitor device through the hardening material injection nozzle.

Advantages of the Invention

[0018] According to the present invention, by increasing the flow rate of the drilling water supplied to the first flow path or the like, the water pressure acting on the valve body is increased, and thereby the valve can be closed. Therefore, it is not necessary to insert a steel ball from the ground surface through a rod as in the prior art of Patent Document 1 to block the drilling water discharge port, and it can also be applied to a rod with a small diameter. Therefore, there is an advantage that it is not affected by the size of the diameter of the rod.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0020] 1. Embodiments of the Present Invention Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0021] The ground improvement device according to the embodiment of the present invention is a ground improvement device provided with a self-boring type monitor device 3 that can be used in both the boring process and the ground improvement process. As shown in FIG. 4(A), it includes a boring machine M installed on the ground, a rod 1, a swivel 2 provided at the base end portion (the upper end portion in the illustrated example) of the rod 1, and a self-boring type monitor device 3 provided at the tip end portion (the lower end portion in the illustrated example) of the rod 1.

[0022] As schematically shown in FIG. 1, the rod 1 is a double-tube rod in which a first flow path 11 that serves as both a boring water flow path and a compressed air flow path and a second flow path 12 that serves as a hardening material flow path are formed. In a sectional view, the second flow path 12 is located at the center of the rod 1, and the first flow path 11 is arranged concentrically around it.

[0023] The swivel 2 is provided with a hole drilling water and compressed air supply port 2a and a hardening material supply port 2b. The hole drilling water and compressed air supply port 2a is connected to the first flow path 11, and the hardening material supply port 2b is connected to the second flow path 12, respectively.

[0024] Note that since the configurations of the boring machine M, the rod 1, and the swivel 2 in this embodiment are almost the same as those used in a conventional double-tube rod type ground improvement device, the configuration of the self-boring type monitor device 3 will be mainly described in detail below.

[0025] As shown in FIGS. 1 and 2, the self-boring type monitor device 3 of this embodiment includes a metal crown (hole drilling bit) 31 and a hole drilling water discharge port 32 at its lower end. Further, at the middle part of the monitor device 3, a hardening material injection nozzle 33 and a compressed air injection nozzle 34 surrounding the periphery thereof are provided concentrically toward the side.

[0026] Inside the monitor device 3, a first flow path 11 and a second flow path 12 extending from inside the rod 1 are formed. Among these, the second flow path 12 further extends inside the monitor device 3 and is connected to the hardening material injection nozzle 33.

[0027] On the other hand, the first flow path 11 branches into a third flow path 13 and a fourth flow path 14 inside the monitor device 3. The third flow path 13 is connected to the hole drilling water discharge port 32, and the fourth flow path 14 is connected to the compressed air injection nozzle 34, respectively. That is, the first flow path 11 is connected to the hole drilling water discharge port 32 via the third flow path 13 and is connected to the compressed air injection nozzle 34 via the fourth flow path 14. Although not shown, a plurality of the third flow paths 13 are formed inside the monitor device 3, and these plurality of third flow paths 13 merge downstream and are connected to the hole drilling water discharge port 32.

[0028] The monitor device 3 of this embodiment is provided with a valve 4 for opening and closing the drilling water discharge port 32. As shown in FIG. 2, this valve 4 includes a valve body 4a made of a steel ball, a valve seat 4b provided below the valve body 4a, a compression coil spring 4c that biases the valve body (steel ball) 4a downward, and a regulating member 5 that regulates the downward movement of the valve body 4a.

[0029] The regulating member 5 includes a rod-shaped member 6 disposed vertically in the outlet passage 32a of the drilling water that communicates with the drilling water discharge port 32, and a rod receiving member 7 spanned horizontally across the drilling water discharge port 32 at the lower part of the outlet passage 32a. The rod-shaped member 6 corresponds to the "longitudinal member" of the present invention, and the rod receiving member 7 corresponds to the "lateral member" of the present invention.

[0030] Among these, as shown in FIGS. 3(A) and (B), the rod-shaped member 6 includes a round rod-shaped rod body 6a and an anti-vibration portion 6b in the shape of a cross in plan view provided at the central portion in the vertical direction thereof. The upper end of the rod body 6a abuts against the valve body 4a, and the lower end abuts against the rod receiving member 7, so that even when the spring pressure of the compression coil spring 4c or the water pressure of the drilling water during drilling acts on the valve body 4a, the valve body 4a functions as a "strut rod" so as not to move downward any further. On the other hand, the anti-vibration portion 6b is for supporting the rod-shaped member 6 straight so that it does not tilt or fall to the left or right in the outlet passage 32a, and is formed in an outer shape that fits inside the outlet passage 32a. The anti-vibration portion 6b is formed in the shape of a cross in plan view in order to allow the passage of the drilling water through the gap. In this embodiment, one anti-vibration portion 6b is provided at the central portion of the rod body 6a, but two or more may be provided along the longitudinal direction of the rod body 6a.

[0031] The rod receiving member 7 is configured as a fragile part that bends or breaks when a water pressure exceeding the water pressure during hole drilling acts on the valve body 4a, and is fixed to the hole drilling water discharge port 32 by a screw (not shown) (in FIGS. 3(C) and 3(D), reference numeral 7a is a screw hole for passing such a screw). Thus, by applying a water pressure exceeding the water pressure during hole drilling to the valve body 4a, the rod receiving member 7 bends or breaks, whereby the restriction of the restricting member 5 is released and the valve body 4a can move downward. Here, the "breakage" includes not only the case where the rod receiving member 7 (lateral member) itself breaks, but also the case where the screw fixing it comes off and the rod receiving member 7 (lateral member) detaches from the hole drilling water discharge port 32, or the case where it is locked only at one end without detaching.

[0032] The compressed air injection nozzle 34 of the self - hole - drilling type monitor device 3 according to the present embodiment is sealed by a sealing member 60. The sealing member 60 in the present embodiment is composed of an annular - belt - shaped aluminum plate, and this aluminum plate is fixed around the compressed air injection nozzle 34 by a screw (not shown). This sealing member 60 is configured to be able to release the seal when a pressure exceeding the water pressure during hole drilling acts. Specifically, it maintains the seal under the water pressure during hole drilling, while when a pressure exceeding the water pressure during hole drilling acts, the aluminum plate is blown away.

[0033] Note that the configuration of the sealing member is not limited to the above - described configuration, and it may be the one described in FIGS. 7·8 or FIGS. 9·10 of Patent Document 1. In any case, the hardening material injection nozzle 33 is not sealed by a sealing member.

[0034] The ground improvement device of the present embodiment configured as described above is used as follows. FIG. 4 is a diagram for explaining the ground improvement method using the same ground improvement device in order of steps. Hereinafter, it will be explained in order of steps.

[0035] 《1》Installation step As shown in FIG. 4(A), a bowling machine M is installed on the ground, and a rod 1 is attached to the bowling machine M. A swivel 2 is attached to the upper end of the rod 1, and the above-described self-boring hole type monitor device 3 is attached to the lower end thereof.

[0036] 《2》Hole boring process Next, as shown in FIG. 4(B), water or bentonite slurry is used as the hole boring water W, and this hole boring water W is supplied to the hole boring water and compressed air supply port 2a of the swivel 2 communicating with the first flow path 11, and the hole boring water W is discharged from the hole boring water discharge port 32 at the lower end of the monitor device 3. At the same time, while rotating the rod 1 by the bowling machine M, a hole is bored to a predetermined depth. As described above, depending on the water pressure of the hole boring water W during this hole boring process, the regulation of the regulating member 5 is not released, and the sealing of the sealing member 60 is not released. Therefore, the hole boring water W is discharged only from the hole boring water discharge port 32 at the lower end of the monitor device 3. The soil generated by the hole boring is sucked and discharged to the ground by the sand pump 50.

[0037] In the hole boring process, the hole boring water W may be supplied into the first flow path 11 and compressed air may be supplied into the second flow path 12 so that the hole boring water W is discharged from the hole boring water discharge port 32 and compressed air is ejected from the hardening material injection nozzle 33. As described above, since the hardening material injection nozzle 33 is not sealed by the sealing member 60, it is possible to eject compressed air from the hardening material injection nozzle 33 during the hole boring process. By ejecting compressed air from the hardening material injection nozzle 33 in this way during the hole boring process, the discharge of the soil generated by the hole boring to the ground surface can be promoted.

[0038] 《3》Valve closing process and sealing release process After the drilling process is completed, when the flow rate (supply flow rate) of the drilling water W to be supplied is increased, since the opening degree of the valve 4 is restricted by the restricting member 5, the water pressure (internal pressure) in the monitor device 3 rises. Due to this rise in water pressure, the rod receiving member 7 configured as a vulnerable part is bent or broken, the valve body 4a moves downward, and the valve 4 is closed. Also, the sealing of the sealing member 60 is released due to the rise in water pressure at this time. When releasing the sealing of the sealing member 60, compressed air may be supplied into the second flow path 12 at the same time, and the compressed air may be injected from the hardening material injection nozzle 33. In this way, while injecting compressed air from the hardening material injection nozzle 33, by releasing the sealing of the sealing member 60 with the drilling water W whose water pressure has risen, it is possible to prevent the drilling water W from flowing backward from the hardening material injection nozzle 33 into the monitor device 3.

[0039] 《4》Test injection process After the valve closing process and the sealing release process, water W0 for test injection is supplied to the hardening material supply port 2b, and compressed air A is supplied to the drilling water and compressed air supply port 2a to perform a test injection (Fig. 4(C)).

[0040] 《5》Ground improvement process (construction process) If there is no abnormality, the water W0 for test injection is switched to the hardening material G, compressed air A is injected from the compressed air injection nozzle 34, and the hardening material G is injected from the hardening material injection nozzle 33. Then, while rotating the rod 1 according to a predetermined turning angle, pulling-up speed, and rotation speed, the rod 1 is pulled up. Thereby, a solidified body (improved body) 40 is formed around the rod 1 to perform ground improvement (Fig. 4(D)).

[0041] 《6》Rod pulling-out and hole filling process When the ground improvement process (construction process) is completed, the rod 1 is pulled out and the hole is filled. Thereby, a series of processes are completed (Fig. 4(E)).

[0042] As described above, according to the ground improvement device and the ground improvement method of the present embodiment, when under the water pressure during drilling, the contact (seating) of the valve body 4a against the valve seat 4b is restricted by the restricting member 5, and the valve 4 maintains an open state, so the drilling process can be carried out without trouble. On the other hand, by applying a water pressure exceeding the water pressure during drilling to the valve body 4a, the restriction by the restricting member 5 is released, the valve body 4a comes into contact (seats) with the valve seat 4b, and the valve 4 is closed. Therefore, by increasing the flow rate of the drilling water W supplied to the first flow path 11 or the like to increase the water pressure acting on the valve body 4a, the drilling water discharge port 32 can be blocked. Thus, it is not necessary to throw in a steel ball from the ground surface through a rod as in the prior art of Patent Document 1 to block the drilling water discharge port 32, and it can also be applied to a small-diameter rod.

[0043] Also, in the ground improvement device and the ground improvement method of the present embodiment, since the sealing member 60 whose sealing is released when a pressure exceeding the water pressure during drilling acts on the compressed air injection nozzle 34 is provided, even when the drilling water W is supplied to the first flow path 11 during drilling, it is possible to prevent the drilling water W from leaking out of the compressed air injection nozzle 34. On the other hand, after the drilling process is completed, the sealing can be released by applying a water pressure exceeding the water pressure during drilling to the sealing member 60, so that the original function as a compressed air injection nozzle can be exhibited thereafter.

[0044] Furthermore, in the sealing release process, when the drilling water W is supplied into the first flow path 11 and compressed air is supplied into the second flow path 12, and while injecting the compressed air from the hardening material injection nozzle 33, the sealing of the sealing member 60 is released by the drilling water W with increased water pressure, it is possible to prevent the drilling water W from flowing back into the monitor device 3 through the hardening material injection nozzle 33.

[0045] 2. Modification Next, a modified example of the present invention will be described with reference to FIGS. 5 and 6. FIG. 5 is an enlarged cross-sectional view near the compressed air injection nozzle of the ground improvement device according to the modified example. This modified example relates to a modified example of the sealing member, and the sealing member 60 in the above embodiment is changed to a sealing member 70 made of a different material and having a different configuration.

[0046] Specifically, in the above embodiment, the compressed air injection nozzle 34 was sealed by the sealing member 60 made of an annular belt-shaped aluminum plate. However, in this modified example, instead, the compressed air injection nozzle 34 is sealed by a sealing member 70 made of a rubber stopper (rubber plug). This rubber plug 70 (sealing member 70) has a frustum of a cone shape and is provided with a through hole in the central portion. This through hole in the central portion is for inserting the hardening material injection nozzle 33. In addition, since the inner peripheral surface of the compressed air injection nozzle 34 in the above-described embodiment and this modified example is formed in a frustum of a cone shape that gradually decreases in diameter in the tip direction, the outer shape of the rubber plug 70 is formed corresponding thereto.

[0047] The rubber plug 70 formed in this way is attached inside the compressed air injection nozzle 34 to seal the nozzle 34. And it is configured to be able to release the seal when a pressure exceeding the water pressure during drilling acts. Specifically, the seal is maintained under the water pressure during drilling, while it is blown off when a pressure exceeding the water pressure during drilling acts. The purpose and function as the sealing member are the same as those of the sealing member 60.

[0048] In addition, as the sealing member, in addition to this rubber plug 70, the sealing member 60 made of the above-described annular belt-shaped aluminum plate may be attached to the tip of the compressed air injection nozzle 34. That is, the sealing members 60 and 70 may be used in combination. Further, the material of the sealing member 70 is not limited to rubber, and it may be made of plastic or wood.

[0049] The embodiments and modifications of the present invention have been described above. However, the present invention is not limited to such embodiments. In the above embodiments, the restricting means was constituted by the restricting member 5 including the rod-shaped member 6 (longitudinal member) and the rod receiving member 7 (lateral member). However, the restricting means is not limited to such a configuration.

[0050] In the above embodiments, the rod receiving member 7 (lateral member) was configured as the vulnerable part. However, the part configured as the vulnerable part is not limited to the rod receiving member 7 (lateral member). The rod-shaped member 6 (longitudinal member) may be configured as the vulnerable part, or both the rod receiving member 7 (lateral member) and the rod-shaped member 6 (longitudinal member) may be configured as the vulnerable part.

[0051] In the above embodiments, the longitudinal member (rod-shaped member 6) and the lateral member (rod receiving member 7) were configured separately, and the lower end portion of the longitudinal member (rod-shaped member 6) was configured to contact the lateral member (rod receiving member 7). However, the two may be integrally configured. When the two are integrally configured, for example, they can be integrated by connecting the lower end portion of the rod-shaped member 6 (longitudinal member) to the rod receiving member 7 (lateral member).

[0052] 3. Reference Example Next, a reference example of the present invention will be described with reference to the drawings. FIGS. 7 to 9 show a ground improvement device according to the reference example. Note that the same reference numerals are given to the members that are the same as or corresponding to the members of the above embodiments, and the description thereof will be omitted.

[0053] The ground improvement device according to the reference example is a ground improvement device equipped with a self-boring type monitor device 103 that can be used in both the drilling process and the ground improvement process, similar to the ground improvement device according to the above embodiment. As shown in Fig. 4(A) (since the overall configuration of the ground improvement device according to the reference example and the outline of each process are the same as those of the ground improvement device according to the embodiment, Fig. 4 is also cited for the reference example. However, when citing Fig. 4 for the reference example, the reference numeral 3 shall be read as the reference numeral 103), it includes a boring machine M installed on the ground, a rod 1, a swivel 2 provided at the base end portion (the upper end portion in the illustrated example) of the rod 1, and a self-boring type monitor device 103 provided at the tip end portion (the lower end portion in the illustrated example) of the rod 1. The configurations of the boring machine M, the rod 1, and the swivel 2 in the reference example are the same as those in the embodiment.

[0054] As shown in Figs. 7 and 8, the self-boring type monitor device 103 of the reference example includes a metal crown (drilling bit) 31 and a drilling water discharge port 32 at its lower end portion. Further, at the middle portion of the monitor device 103, a curing material injection nozzle 33 and a compressed air injection nozzle 34 surrounding the curing material injection nozzle 33 are provided concentrically toward the side.

[0055] Inside the monitor device 103, a first flow path 11 and a second flow path 12 extending from inside the rod 1 are formed. Among these, the second flow path 12 further extends inside the monitor device 3 and is connected to the curing material injection nozzle 33.

[0056] On the other hand, the first flow path 11 branches into a third flow path 13 and a fourth flow path 14 inside the monitor device 103. The third flow path 13 is connected to the drilling water discharge port 32, and the fourth flow path 14 is connected to the compressed air injection nozzle 34, respectively. That is, the first flow path 11 is connected to the drilling water discharge port 32 via the third flow path 13 and is connected to the compressed air injection nozzle 34 via the fourth flow path 14. Although not shown, a plurality of the third flow paths 13 are formed inside the monitor device 103, and these plurality of third flow paths 13 merge downstream and are then connected to the drilling water discharge port 32.

[0057] In the monitor device 103 of the reference example, a valve 104 for opening and closing the drilling water discharge port 32 is provided. As shown in FIG. 8, this valve 104 includes a valve body 104a made of a steel ball, a valve seat 104b provided above the valve body 104a, a compression coil spring 104c that biases the valve body (steel ball) 104a upward, and a regulating member 105 that restricts downward movement of the valve body 104a by a predetermined amount or more. The valve 104 in this reference example is configured such that when receiving the water pressure during drilling, the valve body 104a moves downward against the spring force of the compression coil spring 104c to open the valve, while maintaining the closed valve state depending on the pressure of the compressed air during ground improvement.

[0058] Unlike the regulating member 5 according to the embodiment, the regulating member 105 according to the reference example is configured as a cylindrical lower ball receiving member arranged vertically in the outlet passage 32a of the drilling water communicating with the drilling water discharge port 32. The upper end 105a of this lower ball receiving member 105 is inserted into the inside of the compression coil spring 104c, and an annular ridge 105b (FIG. 9) formed on the outer wall of its cylindrical shape is fixed by fitting into an annular groove 32b (FIG. 8) formed on the inner wall of the outlet passage 32a of the drilling water.

[0059] However, in the normal state (that is, the state where neither drilling water nor compressed air is acting), the upper end 105a of the lower ball receiving member (regulating member) 105 does not protrude from the upper part of the compression coil spring 104c and remains inside it. For this reason, the valve body 104a biased upward by the compression coil spring 104c and the upper end 105a of the lower ball receiving member 105 do not contact each other and are separated from each other. As a result, within this separated range, the valve body 104a can move downward, and there is no obstacle to the valve 104 opening when receiving the water pressure during drilling.

[0060] On the other hand, in this reference example, when water pressure acts during hole drilling, the valve body 104a comes into contact with the upper end 105a of the lower ball receiving member 105. As a result, although the valve 104 in the reference example receives the water pressure during hole drilling and the valve body 104a moves downward to open the valve, the opening degree is restricted by the presence of the lower ball receiving member 105 and does not open beyond a predetermined opening degree.

[0061] Also in this reference example, the point that the compressed air injection nozzle 34 is sealed by the sealing member 60 is the same as in the embodiment. The sealing member 60 in the reference example is also composed of an annular belt-shaped aluminum plate, and this aluminum plate is fixed around the compressed air injection nozzle 34 by screws (not shown). This sealing member 60, similar to the case of the embodiment, maintains the seal under the water pressure during hole drilling, while the seal can be released when a pressure exceeding the water pressure during hole drilling acts. Note that the configuration of the sealing member is not limited to the above configuration and may be the one described in FIGS. 7·8 or FIGS. 9·10 of Patent Document 1 or the rubber stopper 70 (sealing member 70) according to the above modification example. Also, the point that the hardening material injection nozzle 33 is not sealed by a sealing member is the same as in the case of the embodiment.

[0062] The ground improvement device of this reference example configured as described above is used as follows. Hereinafter, it will be described in the order of steps based on FIG. 4. As described above, the reference numeral 3 in FIG. 4 should be read as the reference numeral 103.

[0063] 《1》Installation step As shown in FIG. 4(A), a boring machine M is installed on the ground, and a rod 1 is attached to the boring machine M. A swivel 2 is attached to the upper end of the rod 1, and the above-described self-boring type monitor device 103 is attached to the lower end thereof.

[0064] 《2》Hole drilling step Next, as shown in FIG. 4(B), water or bentonite slurry is used as the boring water W, and this boring water W is supplied to the boring water and compressed air supply port 2a of the swivel 2 communicating with the first flow path 11, and the boring water W is discharged from the boring water discharge port 32 at the lower end of the monitor device 103. While rotating the rod 1 by the boring machine M, boring is performed to a predetermined depth. As described above, due to the water pressure of the boring water W during the boring process, the valve body 104a moves downward against the spring force of the compression coil spring 104c, the valve 104 opens, and the valve body 104a abuts against the upper end 105a of the lower ball receiving member 105, restricting further downward movement. At this time, the sealing of the sealing member 60 is not released. Therefore, the boring water W is discharged only from the boring water discharge port 32 at the lower end of the monitor device 3. The soil generated by boring is sucked and discharged to the ground by the sand pump 50.

[0065] Similar to the case of the embodiment, during the boring process, the boring water W may be supplied into the first flow path 11 and compressed air may be supplied into the second flow path 12 so that the boring water W is discharged from the boring water discharge port 32 and compressed air is injected from the hardening material injection nozzle 33. As described above, since the hardening material injection nozzle 33 is not sealed by the sealing member 60, it is possible to inject compressed air from the hardening material injection nozzle 33 during the boring process. By injecting compressed air from the hardening material injection nozzle 33 in this way during the boring process, the discharge of the soil generated by boring to the ground surface can be promoted.

[0066] 《3》Sealing Release Process After the drilling process is completed, when the supply flow rate of the drilling water W is increased, further downward movement of the valve body 104a is restricted by the lower ball receiving member 105 (that is, since the opening degree of the valve 104 is restricted), the water pressure (internal pressure) of the drilling water W increases. Due to this increase in water pressure, the sealing of the sealing member 60 is released. Similar to the case of the embodiment, when releasing the sealing of the sealing member 60, compressed air may be supplied into the second flow path 12 at the same time, and the compressed air may be injected from the hardening material injection nozzle 33. In this way, while injecting compressed air from the hardening material injection nozzle 33, by releasing the sealing of the sealing member 60 with the drilling water W whose water pressure has increased, it is possible to prevent the drilling water W from flowing back into the monitor device 103 from the hardening material injection nozzle 33.

[0067] 《4》Test injection process After the sealing release process, water W0 for test injection is supplied to the hardening material supply port 2b, and compressed air A is supplied to the drilling water and compressed air supply port 2a to perform a test injection (Fig. 4(C)).

[0068] 《5》Ground improvement process (construction process) If there is no abnormality, the water W0 for test injection is switched to the hardening material G, compressed air A is injected from the compressed air injection nozzle 34, and the hardening material G is injected from the hardening material injection nozzle 33. Then, while rotating the rod 1 according to a predetermined turning angle, pulling-up speed, and number of rotations, the rod 1 is pulled up. Thereby, a solidified body (improved body) 40 is formed around the rod 1 to perform ground improvement (Fig. 4(D)). In this ground improvement process, the valve 104 will maintain a closed valve state.

[0069] 《6》Rod pulling-out and hole filling process When the ground improvement process (construction process) is completed, the rod 1 is pulled out and the hole is filled. Thereby, a series of processes are completed (Fig. 4(E)).

[0070] As described above, according to the ground improvement device and the ground improvement method of the reference example, since the valve body 104a is acted upon by the water pressure during drilling, the valve 104 opens, so the drilling process can be carried out without any problems. On the other hand, in the ground improvement process, since the valve 104 maintains the closed state, there is no need to insert a steel ball from the ground surface through a rod as in the prior art of Patent Document 1 to block the drilling water discharge port 32. Therefore, it can also be applied to a small-diameter rod.

[0071] Further, in the ground improvement device and the ground improvement method of the reference example, since a sealing member 60 is provided in the compressed air injection nozzle 34, the sealing of which is released when a pressure exceeding the water pressure during drilling acts thereon, even when drilling water W is supplied to the first flow path 11 during drilling, it is possible to prevent the drilling water W from leaking out of the compressed air injection nozzle 34. On the other hand, after the completion of the drilling process, the sealing can be released by increasing the supply flow rate of the drilling water W or the like to act a water pressure exceeding the water pressure during drilling on the sealing member 60. Therefore, thereafter, the original function as a compressed air injection nozzle can be exhibited.

[0072] Furthermore, in the sealing release process, when drilling water W is supplied into the first flow path 11 and compressed air is supplied into the second flow path 12, and while injecting compressed air from the hardening material injection nozzle 33, the sealing of the sealing member 60 is released by the drilling water W with increased water pressure, it is possible to prevent the drilling water W from flowing back into the monitor device 3 through the hardening material injection nozzle 33.

[0073] Hereinafter, the main parts of the reference example will be summarized.

[0074] [1] A self-drilling type monitor device including a drilling water discharge port, a hardening material injection nozzle, a compressed air injection nozzle surrounding the hardening material injection nozzle, a first flow path that is a common flow path for drilling water and compressed air, a second flow path for the hardening material, a third flow path connecting the first flow path and the drilling water discharge port, a fourth flow path connecting the first flow path and the compressed air injection nozzle, and a valve for opening and closing the drilling water discharge port. The valve includes a valve body, a valve seat provided above the valve body, and spring means for biasing the valve body upward. The valve is configured to open when the water pressure during hole drilling acts thereon, and to maintain a closed state when the pressure of compressed air during ground improvement acts thereon. A self-drilling type monitor device characterized by this.

[0075] [2] The valve is provided with regulating means that abuts against the valve body and restricts the downward movement of the valve body when a water pressure equal to or exceeding the water pressure during hole drilling acts thereon. As a result, the opening degree of the valve is restricted and it does not open to a predetermined opening degree or more. The compressed air injection nozzle is provided with a sealing member whose sealing is released when a pressure exceeding the water pressure during hole drilling acts thereon. The self-drilling type monitor device according to [1] above, characterized by this.

[0076] [3] The spring means is configured as a compression coil spring. The regulating means is configured as a cylindrical member disposed in the vertical flow path from the valve body to the hole drilling water discharge port. The upper end portion of this cylindrical member is inserted into the inside thereof from below the compression coil spring and is arranged to stay inside. The self-drilling type monitor device according to [2] above, characterized by this.

[0077] [4] A ground improvement method using the self-drilling type monitor device described in [1] above. A hole drilling step of supplying hole drilling water into the first flow path, discharging the hole drilling water from the hole drilling water discharge port, and rotating the monitor device to drill to a predetermined depth. A valve closing step of stopping the supply of the hole drilling water and closing the valve. While rotating and pulling up the monitor device, compressed air and a hardening material are supplied into the first and second flow paths respectively, and compressed air and the hardening material are ejected from the compressed air injection nozzle and the hardening material injection nozzle respectively to improve the surrounding ground. A ground improvement step. A ground improvement method characterized by including

[0078] [5] A ground improvement method using the self-boring type monitor device described in [2] above, A boring step of supplying boring water into the first flow path, rotating the monitor device while discharging the boring water from the boring water discharge port to bore to a predetermined depth, A sealing release step of increasing the water pressure of the boring water to release the sealing of the compressed air injection nozzle by the sealing member, A ground improvement step of improving the surrounding ground by supplying compressed air and a hardening material into the first and second flow paths respectively while pulling up the monitor device while rotating it, and injecting compressed air and the hardening material from the compressed air injection nozzle and the hardening material injection nozzle respectively, A ground improvement method characterized by including

[0079] [6] In the sealing release step, while supplying boring water into the first flow path and supplying compressed air into the second flow path, injecting compressed air from the hardening material injection nozzle, and releasing the sealing of the sealing member by the water pressure of the boring water supplied into the first flow path. The ground improvement method according to [5] above, characterized by this.

Explanation of reference numerals

[0080] 1…Rod, 2…Swivel, 2a…Drilling water and compressed air supply port, 2b…Hardening material supply port, 3…Self-drilling type monitor device (embodiment), 4…Valve, 4a…Steel ball (valve body), 4b…Valve seat, 4c…Compression coil spring, 5…Regulating member, 6…Rod-shaped member, 6a…Rod body, 6b…Vibration damper, 7…Rod receiving member, 7a…Threaded hole, 11…First flow path, 12…Second flow path, 13…Third flow path, 14…Fourth flow path, 31…Metal crown (drilling bit), 32…Drilling water discharge port, 32a…Outlet passage, 32b…Annular recessed strip, 33…Hardening material injection nozzle, 34…Compressed air injection nozzle, 40…Consolidated body (improved body), 50…Sand pump, 60…Sealing member (aluminum plate), 70…Sealing member (rubber stopper), 103…Self-drilling type monitor device (reference example), 104…Valve, 104a…Steel ball (valve body), 104b…Valve seat, 104c…Compression coil spring, 105…Lower ball receiving member (regulating member), 105a…Upper end (of the lower ball receiving member), 105b…Annular ridge, A…Compressed air, G…Hardening material, M…Boring machine, W…Drilling water, W0…Water for test injection

Claims

1. A self-boring type monitor device comprising a boring water discharge port, a hardening material injection nozzle, a compressed air injection nozzle surrounding the hardening material injection nozzle, a first flow path which is a common flow path for boring water and compressed air, a second flow path for the hardening material, a third flow path connecting the first flow path and the boring water discharge port, a fourth flow path connecting the first flow path and the compressed air injection nozzle, and a valve for opening and closing the boring water discharge port, wherein the valve includes a valve body, a valve seat provided below the valve body, spring means for biasing the valve body downward, and regulating means for restricting downward movement of the valve body and preventing contact with the valve seat, the regulating means is configured such that regulation is released when a water pressure exceeding the water pressure during boring acts on the valve body, a self-boring type monitor device characterized by this.

2. At least a part of the regulating means is configured as a fragile part that bends or breaks when a water pressure exceeding the water pressure during boring acts on the valve body, the self-boring type monitor device according to claim 1, characterized in that regulation of the regulating means is released by bending or breaking of the fragile part.

3. The regulating means includes a lateral member extending horizontally so as to cross a vertical flow path from the valve body to the boring water discharge port, and a vertical member extending upward from the lateral member toward the valve body, and the lateral member is configured as the fragile part, the self-boring type monitor device according to claim 2, characterized by this.

4. The compressed air injection nozzle is provided with a sealing member whose sealing is released when a pressure exceeding the water pressure during boring acts thereon, the self-boring type monitor device according to claim 1, characterized by this.

5. A ground improvement method using the self-boring type monitor device according to claim 1, wherein a boring step of supplying boring water into the first flow path, discharging the boring water from the boring water discharge port, and rotating the monitor device to bore to a predetermined depth; a valve closing step of increasing the water pressure of the boring water to release the regulation of the regulating means and closing the valve; a ground improvement step of improving the surrounding ground by injecting compressed air and a hardening material from the compressed air injection nozzle and the hardening material injection nozzle respectively by supplying compressed air and the hardening material into the first and second flow paths respectively while pulling up the monitor device while rotating it. A ground improvement method characterized by including

6. A ground improvement method using the self-boring type monitor device according to claim 4, a boring step of supplying boring water into the first flow path, rotating the monitor device while discharging the boring water from the boring water discharge port, and boring to a predetermined depth; a valve closing step of increasing the water pressure of the boring water to release the regulation of the regulating means and closing the valve; a sealing release step of releasing the sealing of the compressed air injection nozzle by the sealing member by the increased water pressure of the boring water; a ground improvement step of improving the surrounding ground by supplying compressed air and a hardening material into the first and second flow paths respectively while pulling up the monitor device while rotating it, and injecting compressed air and the hardening material from the compressed air injection nozzle and the hardening material injection nozzle respectively; a ground improvement method characterized by including

7. In the sealing release step, while supplying boring water into the first flow path and supplying compressed air into the second flow path, and injecting compressed air from the hardening material injection nozzle, the sealing of the sealing member is released by the water pressure of the boring water supplied into the first flow path. The ground improvement method according to claim 6, characterized by this.

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