Engaging state confirmation device and engaging state confirmation method of steel pipe sheet pile joint

Abstract

To provide an engaging state confirmation device of a steel pipe sheet pile joint that can accurately confirm an engaging state of a steel pipe sheet pile joint with a simple mechanical structure, and an engaging state confirmation method using the same.SOLUTION: A an engaging state confirmation device of a steel pipe sheet pile joint comprises: a cut detection pipe 20 having a cut detection portion 20a arranged across a slit portion 6 at a predetermined height position in a pipe axial direction of one of the joint members 4; fluid pressurizing means pressurizing fluid filled in the cut detection pipe 20 from the ground; and pressure measuring means measuring pressure of the fluid in the cut detection pipe 20. An engagement state of both joint members 4, 5 is detected by change in the pressure of the fluid in the cut detection pipe 20 when a part of the joint member 4 is inserted into the slit portion 6 and the cut detection portion 20a is cut.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an engagement state confirmation device for a steel pipe sheet pile joint used to confirm the engagement state of a steel pipe sheet pile joint connecting adjacent steel pipe sheet piles, and an engagement state confirmation method using the same. [Background technology]

[0002] A continuous steel pipe sheet pile wall 1 used for retaining walls, steel pipe sheet pile shaft foundations, etc. is connected between adjacent steel pipe sheet piles 2, 2 via a joint structure (hereinafter referred to as steel pipe sheet pile joint 3) as shown in Figure 8.

[0003] The steel pipe sheet pile joint 3 has a pair of joint members 4, 5 supported on the outer circumferential ends of adjacent steel pipe sheet piles 2, 2, and is configured to connect adjacent steel pipe sheet piles 2, 2 by engaging the joint member 5 of the trailing steel pipe sheet pile 2 with the joint member 4 of the leading steel pipe sheet pile 2 and driving the trailing steel pipe sheet pile 2.

[0004] Three types of steel pipe sheet pile joints of this type are widely used as standard structures: the so-called "PT type" joint, the "PP type" joint, and the "LT type" joint.

[0005] As shown in Figure 9, the "PT type" joint has one of the joint members 4 that is engaged and made of a steel pipe (hereinafter referred to as the joint steel pipe 4), one diametric end of which is fixed to the outer peripheral surface of the steel pipe sheet pile 2 by welding or the like, and a slit portion 6 is formed on the other end side along the vertical direction.

[0006] The slit portion 6 is formed so that its width in the tangential direction is wider than the thickness of a part (hereinafter referred to as a support portion 7) of the other joint member 5, which will be described later, so that the support portion 7 can be inserted in the vertical direction.

[0007] The joint member 5 comprises a support portion 7 fixed to the outer periphery of the steel pipe sheet pile 2 and an engagement portion 8 supported by the support portion 7, and the support portion 7 and the engagement portion 8 form a T-shape in plan view, so that the support portion 7 is inserted into the slit portion 6 of the joint steel pipe 4 and the engagement portion 8 is engaged with the joint steel pipe 4.

[0008] As shown in Figure 10, the "PP type" joint has joint steel pipes 9, 10 fixed to the outer surfaces of adjacent steel pipe sheet piles 2, 2, and the joint steel pipes 9, 10 are engaged with each other through slits 11, 11 formed in the joint steel pipes 9, 10.

[0009] As shown in Figure 11, the "LT type" joint comprises a pair of angle irons 12, 12 fixed opposite to the outer peripheral surface of one of the adjacent steel pipe sheet piles 2, and a T-shaped steel 5 supported on the outer peripheral surface of the other steel pipe sheet pile 2, and the support portion 7 of the T-shaped steel 5 is inserted into a slit portion 13 formed between the angle irons 12, 12 supported by one of the steel pipe sheet piles 2, and the engaging portion 8 supported by the support portion 7 engages with both angle irons 12, 12.

[0010] In this type of steel pipe sheet pile joint, it is important that the joint parts are properly engaged with each other in order to ensure rigidity between the steel pipe sheet piles and watertight performance, and it is desirable to confirm that the joint parts are properly engaged with each other during construction.

[0011] On the other hand, a technology has been developed to check the engagement state of the joints connecting adjacent steel sheet piles, in which a detection wire made of an electric wire or the like is placed in the gap of the joint part of the steel sheet pile that is driven in first, and the engagement state is checked based on the electrical current state of the detection wire (see, for example, Patent Document 1).

[0012] In this confirmation method using a detection line, the joint part of the trailing steel sheet pile is inserted into the gap formed in the joint part of the leading steel sheet pile, causing the joint part of the trailing steel sheet pile to come into contact with the detection line, and by cutting the detection line, the circuit containing the detection line changes from a conducting state to a non-conducting state, thereby detecting that the joint parts of the steel sheet piles are properly engaged with each other. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-2710 Summary of the Invention [Problem to be solved by the invention]

[0014] The conventional technology described above is a simple sensing technology that uses electrical signals, optical signals, etc., and requires the joint member of the trailing steel pipe sheet pile to engage with the joint member of the steel pipe sheet pile that is being driven in advance, and the detection wire to be cut by the trailing joint member, thereby changing from an energized state to a non-energized state (or from a non-energized state to an energized state).

[0015] However, in the joint structure of a steel pipe sheet pile, the width of the slit portion formed in the joint steel pipe or the slit portion formed between the angle irons is set larger than the width of the portion where the other joint member is inserted into the slit portion, compared to the gap in the joint structure of the steel sheet pile, allowing the other joint member to move a certain amount within the slit portion and absorbing positional deviation due to eccentricity when driving the steel pipe sheet pile.

[0016] Therefore, in the conventional technology described above, if the eccentricity of the other coupling member within the slit portion is large, even if the coupling members are properly engaged with each other, the position of the other coupling member may deviate from the installation location of the detection body, and the detection line may not be cut.

[0017] Furthermore, in order to avoid the problems described above, it is preferable that the detection wire be wired in a direction that crosses the slit portion so that the detection wire is reliably cut by the support portion inserted into the slit portion. However, in this case, the detection wire needs to be routed along the outer or inner surface of the joint steel pipe, and there is a risk that the detection wire will be broken during or after the casting of the steel pipe sheet pile due to reasons other than the engagement of the joint parts, such as the penetration resistance of the ground or contact with gravel.

[0018] Therefore, in consideration of these conventional problems, the present invention has been made with the aim of providing an engagement state confirmation device for steel pipe sheet pile joints that can accurately confirm the engagement state of steel pipe sheet pile joints with a simple mechanical structure, and an engagement state confirmation method using the same. [Means for solving the problem]

[0019] The feature of the invention described in claim 1 for solving the above-mentioned conventional problems is that the device for checking the engagement state of a steel pipe sheet pile joint, which detects the engagement state of a steel pipe sheet pile joint in which one of the coupling members connecting adjacent steel pipe sheet piles is engaged with a part of the other coupling member inserted into a vertical slit portion formed in the other coupling member, comprises a cut detection unit arranged across the slit portion at a predetermined height in the pipe axial direction of one of the coupling members, a cut detection tube having at least one end extended to the ground along the coupling member, a fluid pressurizing means for pressurizing the fluid filled in the cut detection tube from the ground, and a pressure measuring means for measuring the pressure of the fluid in the cut detection tube, wherein the engagement state of the two coupling members is detected by the change in pressure of the fluid in the cut detection tube when a part of the other coupling member is inserted into the slit portion and the cut detection unit is cut.

[0020] The invention as set forth in claim 2 is characterized in that, in addition to the configuration of claim 1, a protective cover that covers the surface of the disconnection detection portion is fixed to the outer peripheral surface of the one joint member.

[0021] The invention as set forth in claim 3 is characterized in that, in addition to the configuration of claim 1 or 2, the fluid is an ester-based synthetic oil or an animal or vegetable oil.

[0022] The invention described in claim 4 is characterized in that, in a method for checking the engagement state of a steel pipe sheet pile joint, one of the coupling members connecting adjacent steel pipe sheet piles is engaged with a part of the other coupling member inserted into a vertical slit formed in the other coupling member, the two coupling members are engaged, the method comprising: drawing out at least one end of a cutoff detection tube, the cutoff detection part of which is arranged at a predetermined height position in the pipe axis direction of one of the coupling members so that it crosses the slit, along the coupling member to the ground; driving one of the adjacent steel pipe sheet piles into the ground first; pressurizing the fluid in the cutoff detection tube to a predetermined pressure and measuring the fluid pressure; driving the other steel pipe sheet pile in this state; inserting a part of the other coupling member into the slit; and detecting that the two coupling members are engaged by the drop in pressure of the fluid when the part of the other coupling member passes through the predetermined height position and the cutoff detection part is broken.

[0023] The feature of the invention described in claim 5 is that, in addition to the configuration of claim 4, the specified pressure to which the fluid is pressurized is higher than the earth pressure and / or water pressure at the depth at which the cut detection section of the ground into which the steel pipe sheet pile is driven is expected to break. [Effects of the Invention]

[0024] The engagement state confirmation device for steel pipe sheet pile joints of the present invention, by being equipped with the configuration described in claim 1, can accurately grasp the engagement state of the steel pipe sheet pile joint by the pressure change of the fluid inside the cut detection pipe.

[0025] Furthermore, in the present invention, by providing the configuration described in claim 2, it is possible to prevent the cut detection pipe from being damaged by the penetration resistance of the ground or by contact with gravel or the like.

[0026] Furthermore, in the present invention, by providing the configuration described in claim 3, even if a fluid flows out into the ground, it is decomposed, so that contamination of the ground can be prevented.

[0027] Furthermore, in the present invention, by providing the configuration described in claim 4, the engagement state of the steel pipe sheet pile joint can be accurately grasped based on the pressure change of the fluid in the cut detection pipe.

[0028] Furthermore, in the present invention, by providing the configuration described in claim 5, the pressure after the breakage of the cutoff detection unit can be compared with the earth pressure and / or water pressure at the planned cutting depth, making it possible to grasp the breakage of the cutoff detection unit and the engagement status of the coupling members. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view showing a usage mode of the engagement state confirmation device for a steel pipe sheet pile joint according to the present invention. FIG. [Figure 2] FIG. [Figure 3] FIG. 3 is an enlarged vertical cross-sectional view showing a protective cover portion in FIG. 2. [Figure 4] FIG. 2 is an enlarged cross-sectional view showing the installation state of the cut detection pipe of the same. [Figure 5] This is a schematic front view showing the procedure for connecting the cut detection tube when connecting the above-mentioned steel pipe sheet pile, where (a) shows the state after the connecting pile member is connected, and (b) shows the state after the cut detection tube is connected. [Figure 6] FIG. 10 is a perspective view showing the state of the work of pressurizing the fluid in the cut detection pipe after pouring the same. [Figure 7] FIG. 10 is a perspective view showing the state in which the steel pipe sheet pile joint is engaged and the cut detection portion is broken. [Figure 8] FIG. 1 is a front view showing a conventional steel pipe sheet pile wall during construction. [Figure 9] FIG. 1 is a plan view showing an embodiment of a "PT type" joint, which is an example of a steel pipe sheet pile joint. [Figure 10] FIG. 2 is a plan view showing an embodiment of the "PP type" joint of the same. [Figure 11] FIG. 2 is a plan view showing an embodiment of the "LT type" joint of the same. DETAILED DESCRIPTION OF THE INVENTION

[0030] Next, an embodiment of the device for checking the engagement state of a steel pipe sheet pile joint according to the present invention will be described based on the embodiment shown in Figs.

[0031] In this embodiment, a so-called PT type steel pipe sheet pile joint will be described as an example, and the same components as those in the above-mentioned conventional example will be given the same reference numerals and description thereof will be omitted.

[0032] In addition, in the figure, reference numeral 15 denotes the tip shoe of the closing plate that closes the obliquely cut lower end of the steel pipe for joint 4, reference numeral 16 denotes the bottom surface of the water, and reference numeral 17 denotes the water surface.

[0033] As shown in Figure 1, the engagement state confirmation device (hereinafter referred to as the confirmation device) for steel pipe sheet pile joints comprises a cut detection tube 20 having a cut detection section 20a arranged across the slit section 6 at a predetermined height position in the pipe axial direction of one of the joint members (joint steel pipe 4), a fluid pressurizing means (not shown) for pressurizing the fluid (not shown) filled in the cut detection tube 20 from the ground, and a pressure measuring means 21 for measuring the pressure of the fluid in the cut detection tube 20.The other joint member 5 is inserted into the slit section 6, and the engagement state of both joint members 4, 5 is detected by the change in the pressure of the fluid in the cut detection tube 20 when the cut detection section 20a is cut.

[0034] The cut detection pipe 20 is formed in the shape of a flexible hose made of metal or resin, and can be arranged by being laid around the outer circumferential surface of the steel pipe for joint 4 in the circumferential direction.

[0035] The means for fixing this cut detection pipe 20 to the steel pipe for joint 4 is not particularly limited, but it can be fixed using welding, adhesive, a U-shaped fixture, a bolt, a nut, or the like.

[0036] As shown in Figs. 2 and 3, a protective cover 22 made of angle iron or the like may be fixed to the outer circumferential surface of the joint steel pipe 4 to cover the surface of the cut detection section 20a.

[0037] This protective cover 22 comprises, for example, a base plate 22a made of flat steel fixed across both sides of the slit section 6, and a cover body 22b made of angle iron or the like fixed to the surface of the base plate 22a with both end openings facing horizontally, and is configured to cover the cut detection section 20a by inserting the cut detection tube 20 between the base plate 22a and the cover body 22b.

[0038] This protective cover 22 is fixed with enough strength that the base plate 22a does not fall off when the joint steel pipe 4 penetrates the ground, and will fall off when a predetermined external force is applied to the outer surface of the joint steel pipe 4, so as not to hinder the cut detection section 20a from being cut by the other joint member 5.

[0039] This cut detection pipe 20 has a predetermined pressure resistance performance, specifically, it is designed to be able to withstand high pressures several times higher than the earth pressure and / or water pressure at the depth from the water surface at the position where it is cut by the other coupling member 5 when both coupling members 4, 5 are engaged (hereinafter referred to as the installation depth), and is strong enough to be cut by the shear force of the other coupling member 5. Here, earth pressure and / or water pressure refers to either the earth pressure when only earth pressure is applied, the water pressure when only water pressure is applied, or the resultant force of earth pressure and water pressure when both earth pressure and water pressure are applied.

[0040] One end of this cut detection pipe 20 is closed by a closing member 23, and the other end is composed of a transmission pipe section 24 whose end is extended to the ground along the joint steel pipe 4, as shown in Figures 1 and 4. In the figures, reference numeral 25 denotes a protective member for protecting the cut detection pipe 20 (transmission pipe section 24).

[0041] The transmission pipe section 24 may be constructed from a flexible hose similar to the main body of the cut detection pipe 20, or a separate member from the main body of the cut detection pipe 20, such as a polyvinyl chloride pipe, may be used to connect the transmission pipe section 24 to the other end of the main body of the cut detection pipe 20.

[0042] The cut detection pipe 20 may be configured as a flexible hose, with the end of the cut detection pipe 20 being drawn above ground without passing through the transmission pipe section 24.

[0043] Furthermore, when the steel pipe sheet pile 2 is constructed by connecting multiple joint pile members 2a, 2a... in the axial direction, as shown in Figure 5, pipe materials 24a, 24a constituting the transmission pipe section 24 can be fixed to each joint pile member 2a, 2a..., and after the joint pile members 2a, 2a are connected, the joint steel pipe 4 can be connected by a distant piece 4a, and then the pipe materials 24a, 24a can be connected by a pipe joint 24b.

[0044] The fluid filled in the cut detection tube 20 is not particularly limited, but is composed of a fluid such as water or oil, and in the case of oil, it is desirable that it be an ester-based synthetic oil or an animal or vegetable oil, which are highly biodegradable oils, taking into consideration the impact on the environment if it flows into the ground after cutting.

[0045] The fluid pressurizing means is made up of a pressure pump, accumulator, etc., and is capable of pressurizing the fluid inside the cut detection pipe 20. An on-off valve 26 is installed at the end of the cut detection pipe 20 (transmission pipe section 24), and by opening the on-off valve 26, the fluid inside the cut detection pipe 20 can be pressurized by the pressurizing means, and by closing the on-off valve 26 after pressurization, the pressure of the fluid inside the cut detection pipe 20 can be maintained at a predetermined pressure.

[0046] The means for maintaining the pressure of the fluid inside the cutoff detection pipe 20 may be a means for maintaining the pressurized state by a pressurizing means without using the on-off valve 26.

[0047] The pressure measuring means 21 is composed of a pressure gauge arranged downstream of the on-off valve 26 (on the cut detection section 20a side), and is capable of measuring the pressure inside the cut detection pipe 20 including the cut detection section 20a.

[0048] Furthermore, the pressure measuring means 21 may use a communication means (not shown) to output the measured value as needed to a recording medium, a computer device, a pre-registered mobile terminal, or the like.

[0049] Next, a method for checking the engagement state of a joint using the checking device as described above will be described. Note that the same components as those in the above embodiment will be given the same reference numerals and the description thereof will be omitted.

[0050] First, the tip of the cut detection pipe 20 is fixed circumferentially at a predetermined height position of one of the joint members (joint steel pipe 4) of the steel pipe sheet pile 2 to be cast first, and a cut detection section 20a is arranged across the slit section 6.The other end of the cut detection pipe 20 (transmission pipe section 24) is installed along the axial direction of the joint steel pipe 4 so that the end remains pulled out above ground even after casting, and is pulled out from the upper end of the joint steel pipe 4.A pressure gauge, which is a pressure measurement means 21, is interposed in the part pulled out from the upper end of the joint steel pipe 4, and an opening / closing valve 26 is installed above the pressure measurement means 21.

[0051] Furthermore, a pressure pump, an accumulator, etc. (not shown) constituting a fluid pressurizing means are installed upstream of the on-off valve 26 of the cutoff detection pipe 20, and the cutoff detection pipe 20 is filled with fluid.

[0052] The cut detection unit 20a is preferably installed at the lower end of the steel pipe 4 to confirm that the other joint member 5 (support part 7) has reached the lower end (near the deepest part in the vertical direction) of the steel pipe 4 relative to one of the joint members (steel pipe 4), but it may also be installed midway through the steel pipe 4 to observe the progress along the way. It may also be installed at multiple locations, midway through and at the lower end.

[0053] Next, after completing the installation of the cut detection pipe 20, the fluid pressurizing means, and the pressure measuring means 21, the leading steel pipe sheet pile 2 is driven into the ground. Note that when the leading steel pipe sheet pile 2 is driven, the on-off valve 26 is kept open.

[0054] When the leading steel pipe sheet pile 2 is driven, the cut detection pipe 20 has a certain strength, so it is prevented from breaking due to penetration resistance from the ground or contact with gravel, etc. Furthermore, the use of the protective member 25 reduces contact between the cut detection pipe 20 and gravel, etc. during penetration.

[0055] 6, once the driving of the leading steel pipe sheet pile 2 is completed, the fluid pressurizing means is activated, and while the fluid pressure is measured by the pressure measuring means 21, the fluid in the cutoff detection pipe 20 is pressurized to a predetermined pressure, specifically, a pressure higher than the earth pressure and / or water pressure at the depth at which the other coupling member 5 will cut when the two coupling members 4, 5 are engaged (the installation depth of the cutoff detection unit 20a), and then the on-off valve 26 is closed to maintain the fluid pressure in the cutoff detection pipe 20 at the predetermined pressure. It is desirable that the predetermined pressure be at least twice the earth pressure and / or water pressure at the depth at which the other coupling member 5 will cut when the two coupling members 4, 5 are engaged (the installation depth of the cutoff detection unit 20a).

[0056] The vertical soil water pressure P at each depth x from the water surface can be calculated as the sum of the vertical water pressure Pw (= γw * x) at each depth x from the water surface and the vertical earth pressure Ps (= γ's * (xy)) at each depth x from the water surface. Note that γw is the unit weight of water, γ's is the effective unit weight of soil, and y is the depth from the water surface to the bottom.

[0057] For example, if the depth y from the water surface to the bottom is 10 m, and the unit weight of water γw and the effective unit weight of soil γ´s are 10 kN / m 3 As a result, the calculated results of the vertical soil water pressure at each depth from the water surface are as shown in Table 1. When the installation depth of the cut detection unit 20a is 100 m, the fluid inside the cut detection pipe 20 is pressurized to a pressure higher than the vertical soil water pressure P = 1.9 MPa at that depth, preferably to about 4 MPa.

[0058] [Table 1]

[0059] The method for maintaining the pressure of the fluid inside the cutoff detection pipe 20 may be such that the pressure is maintained by a fluid pressurizing means without using the on-off valve 26.

[0060] After the driving of the leading steel pipe sheet pile 2 and the installation of the engagement state confirmation device are completed, the driving of the trailing steel pipe sheet pile 2 is carried out. If the engagement of the steel pipe sheet pile joints needs to be confirmed when driving the next steel pipe sheet pile (trailing steel pipe sheet pile) after the driving of the trailing steel pipe sheet pile 2, an engagement state confirmation device is installed on the trailing steel pipe sheet pile 2 as well as on the leading steel pipe sheet pile 2.

[0061] The trailing steel pipe sheet pile 2 is cast by aligning the support portion 7 with the position of the slit portion 6 of the joint steel pipe 4 so that the engaging portion 8 of the joint member 5 of the trailing steel pipe sheet pile 2 is positioned inside the joint steel pipe 4 of the leading steel pipe sheet pile 2, engaging both joint members 4, 5, and driving the pile downward in this state.

[0062] As the driving of the trailing steel pipe sheet pile 2 progresses with both joint members 4, 5 engaged, the support part 7 is lowered with inserted into the slit part 6, and reaches the position where the cut detection part 20a is installed. Note that, since the location where the cut detection part 20a is fixed in the leading steel pipe sheet pile 2 is known, the timing for checking the engagement of the joints can also be determined by measuring the driving depth of the trailing steel pipe sheet pile 2.

[0063] When the support part 7 reaches the position of the cut detection part 20a, it comes into contact with the cut detection part 20a, which is arranged across the slit part 6, as shown in Figure 7, and cuts the cut detection part 20a of the cut detection pipe 20, thereby releasing the pressure inside the cut detection pipe 20.

[0064] As a result, the pressure measured by the pressure measuring means 21 drops from the set predetermined pressure, and it can be detected that the support part 7 has passed through the slit part 6 at the position where the cut detection part 20a is installed.

[0065] At this time, a pressure equivalent to the earth pressure and / or water pressure P at the installation depth of the cut detection unit 20a acts on the cross section of the cut detection pipe 20 where the pressure has been released by cutting. Therefore, by making the pressure inside the cut detection pipe 20 before cutting (a predetermined pressure) higher than the earth pressure and / or water pressure at the installation depth of the cut detection unit 20a (for example, more than twice as high), the pressure difference before and after cutting becomes clearly apparent, and it becomes possible to accurately detect the cutting of the cut detection pipe 20, i.e., that the support unit 7 has passed through the slit portion 6 at the position where the cut detection unit 20a is installed.

[0066] In the method of confirming engagement of a steel pipe sheet pile joint configured in this manner, the cut detection section 20a of the cut detection pipe 20 is arranged so as to cross the slit section 6, so that the engagement state can be reliably confirmed even if the support section 7 moves eccentrically relative to the slit section 6.

[0067] Furthermore, since the state of the cutoff detection section 20a can be grasped by the pressure change inside the cutoff detection pipe 20, the engagement state of the steel pipe sheet pile joint can be accurately grasped by a mechanical structure without relying on sensing technology.

[0068] In the above embodiment, the so-called "PT type" joint has been taken as an example, but the present invention can also be applied to "PP type" and "LT type" joints.

[0069] Furthermore, in the above-mentioned embodiment, the steel pipe sheet pile is cast from above the water surface, and the engagement of the steel pipe sheet pile joint is confirmed underwater below the water bottom and in the ground below the water bottom. However, the present invention can also be used to cast the steel pipe sheet pile from the ground surface, and to confirm the engagement of the steel pipe sheet pile joint in the ground. [Explanation of symbols]

[0070] 20 Cut detector tube 21 Pressure measuring means 22 Protective Cover 23 Closure member 24 Transmission pipe section 25 Protective materials 26 On-off valve

Claims

1. A steel pipe sheet pile joint engagement state confirmation device detects an engagement state of a steel pipe sheet pile joint in which one of the joint members connecting adjacent steel pipe sheet piles is engaged with the other joint member in a state in which a part of the other joint member is inserted into a vertical slit portion formed in the other joint member, a cut detection pipe having a cut detection section disposed across the slit section at a predetermined height in the pipe axis direction of one of the coupling members, at least one end of which is drawn out to the ground along the coupling member; fluid pressurizing means for pressurizing the fluid filled in the cut detection pipe from the ground; and pressure measuring means for measuring the pressure of the fluid in the cut detection pipe, A steel pipe sheet pile joint engagement state confirmation device characterized in that a part of the other joint member is inserted into the slit portion, and the engagement state of the two joint members is detected by the change in fluid pressure in the cutoff detection pipe when the cutoff detection portion is cut.

2. 2. The apparatus for checking the engagement state of a steel pipe sheet pile joint according to claim 1, wherein a protective cover covering a surface of the breakage detection portion is fixed to an outer peripheral surface of the one joint member.

3. 3. The apparatus for checking the engagement state of a steel pipe sheet pile joint according to claim 1, wherein the fluid is an ester-based synthetic oil or an animal or vegetable oil.

4. A method for checking the engagement state of a steel pipe sheet pile joint, which detects the engagement state of a steel pipe sheet pile joint in which one of the coupling members connecting adjacent steel pipe sheet piles is engaged with the other coupling member in a state in which a part of the other coupling member is inserted into a vertical slit portion formed in the other coupling member, At least one end of a cut detection pipe is arranged at a predetermined height in the pipe axis direction of the one joint member so that a cut detection section crosses the slit section, and the cut detection pipe is pulled out to the ground along the joint member, After one of the adjacent steel pipe sheet piles is driven into the ground first, the fluid in the cut detection pipe is pressurized to a predetermined pressure and the pressure of the fluid is measured; A method for checking the engagement state of a steel pipe sheet pile joint, characterized in that the other steel pipe sheet pile is driven in that state, a part of the other joint member is inserted into the slit portion, and when the part of the other joint member passes the specified height position, the disconnection detection portion is broken and the pressure of the fluid drops, detecting that the two joint members are engaged.

5. A method for confirming the engagement state of a steel pipe sheet pile joint as described in claim 4, wherein the specified pressure to which the fluid is pressurized is higher than the earth pressure and / or water pressure at the depth at which the cut detection portion of the ground into which the steel pipe sheet pile is driven is expected to break.

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