Static cone test device and static cone test method

Abstract

To provide a static cone test device and a static cone test method capable of economically and efficiently carrying out the static cone test from an inside of an underground structure without requiring any large preparation work.SOLUTION: A static cone test device 50 is to measure ground characteristics by pressing-in a probe 15 in a cone shape into the ground from an inside of the structure S, being provided with: a rod 10 penetrated into a through hole H arranged in the structure and having a prove 15 at a tip thereof; a fixation part 20 to be fixed on the structure S; a telescopic part 30 a base end side of which is fixed on the fixation part 20 and telescoping through gaining reaction force from the fixation part 20; and a grip part 40 fixed at a tip side of the telescopic part 30 and griping part of the rod 10, wherein the prove 15 at the tip of the rod 10 is pressed-in into the ground G through shrinkage of the telescopic part 30 in a situation the griping part 40 grips part of the rod 10.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a static cone test apparatus and method. [Background technology]

[0002] There are various methods for geological investigations, including the Swedish Sounding Test (SWS) and the Static Cone Penetration Test (CPT). Of these, the static cone penetration test is a test method based on the Geotechnical Society standard (JGS1435-2012) in which a cone-shaped probe is statically pressed into the ground from the ground (for example, at a speed of about 20 mm / sec) to measure ground characteristics (soil type classification, N-value, fine particle content, etc.).The test simultaneously measures three components: the resistance of the probe at the tip, pore water pressure (the pressure of water between soil particles), and the friction of the surface of the probe itself. The static cone penetration test can also be called an electric static cone penetration test, and can simultaneously obtain various ground information such as the bearing capacity of the ground, soil classification, and liquefaction assessment. Furthermore, compared to drilling surveys and indoor soil tests, it is easier to carry out, can directly and continuously measure information about the original ground, and is a highly reliable survey method, so it is a survey method that is commonly used in Europe, North America, and other regions.

[0003] Since static cone tests are conducted on the ground, the test equipment is generally constructed by installing a base machine, which is a modified pile driver, on the ground. In this test equipment, a rod with a probe at the tip is attached to a hammer head on the base machine. When the hammer head presses the rod into the ground, a penetration force of, for example, 5 to 8 tons (which varies depending on the soil quality) is generated. To resist this penetration force, the base machine is fixed to the ground with a screw anchor (an example of an anchor). If a static cone test, which is normally performed from above ground, is to be performed from inside an underground structure, it becomes necessary to create temporary openings in the underground structure that were not originally intended when installing the anchors. As a result, situations may arise where it is not possible to create temporary openings in the underground structure, such as the underground structure's underground frame, shield segments, or shield tunneling machine, and in such cases, the static cone test cannot be performed. Furthermore, since static cone testing requires the above-mentioned base machine, the preparatory work, such as installing the base machine and anchors inside the underground structure, becomes extremely extensive, making it an uneconomical testing method, and from this perspective, conducting static cone testing from inside an underground structure may be inappropriate.

[0004] In view of the above, there is a need for a static cone test device and method that can be economically implemented without requiring extensive preparation work when conducting static cone tests from inside underground structures.

[0005] Here, Patent Document 1 proposes a method for investigating the natural ground around a tunnel, which investigates the natural ground around buried pipes or segment rings buried in a tunnel formed by a tunneling machine. This investigation method involves attaching a water stop valve, through which an investigation rod can be inserted when the valve is open, to the inside of a through hole provided in a buried pipe or segment ring so as to penetrate from the inside to the outside, and connecting a packing jig, which has a through hole through which the investigation rod can be inserted and has packing material that can stop water from entering the outer periphery of the investigation rod, to the inside of the water stop valve when the valve is closed.The tip of the investigation rod is inserted into this packing jig up to just before the water stop valve in the closed state, and with the water stopped by the packing jig, the water stop valve is opened and the investigation rod is inserted through the inside of the water stop valve and inserted into the natural ground.This is a method for investigating the natural ground around a tunnel. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-138489 Summary of the Invention [Problem to be solved by the invention]

[0007] The method for investigating the ground surrounding a tunnel described in Patent Document 1 is said to enable simple, low-cost investigations that ensure watertightness when investigating buried pipes used in jacking and shield construction methods, the amount of over-excavation around tunnel segments, and soil quality. However, the present invention does not provide a test device or test method that can solve the above-mentioned problem, i.e., perform static cone testing from inside an underground structure economically without requiring extensive preparation work.

[0008] The present invention aims to provide a static cone testing device and a static cone testing method that can economically and efficiently conduct static cone testing from inside an underground structure without the need for extensive preparation work. [Means for solving the problem]

[0009] In order to achieve the above object, one aspect of the static cone test device according to the present invention is: A static cone test device that measures ground characteristics by statically pressing a cone-shaped probe into the ground from inside a structure, comprising: a rod that is inserted into a through-hole provided in the structure and has the probe at its tip; a fixing portion fixed to the structure; an expandable portion whose base end side is fixed to the fixed portion and expands and contracts by receiving a reaction force from the fixed portion; a gripping portion fixed to a tip side of the extension / contraction portion and gripping a part of the rod; The telescopic part contracts while the gripping part grips a part of the rod, thereby forcing the probe at the tip of the rod into the ground.

[0010] According to this aspect, the telescopic part expands and contracts in response to a reaction force from the fixed part fixed to the structure, and the rod, which is held by the holding part fixed to the telescopic part and has a probe at its tip, is pressed into the ground by the contraction of the telescopic part, thereby eliminating the need for extensive preparation work required to install a base machine, anchors, etc., and making it possible to conduct static cone tests economically and efficiently from inside an underground structure. Here, structures (underground structures) to which the static cone test device of this embodiment can be applied include underground structures made of RC (Reinforced Concrete), S (Steel), and SRC (Steel Reinforced Concrete), as well as already constructed structures such as underground road tunnels, railway tunnels (e.g., shield tunnels), railway stations, and basements of buildings and apartment buildings, as well as shield tunneling machines currently constructing shield tunnels.

[0011] In another aspect of the static cone test device according to the present invention, The stretchable portion is a stationary member attached to the fixed portion and including a first insertion hole through which the rod is inserted; a hydraulic cylinder attached to the stationary member; a movable member attached to a piston of the hydraulic cylinder, sliding together with the piston, and having a second insertion hole through which the rod is inserted; The gripping portion is attached to the movable member.

[0012] According to this aspect, the movable member to which the gripping part that grips the rod is attached is slid by the hydraulic cylinder, so that the rod with the probe at its tip can be stably and reliably pressed into the ground. Here, in addition to a form in which the movable member is slid by one hydraulic cylinder, a form in which multiple (for example, two) hydraulic cylinders are provided side by side and are synchronously controlled is also included.

[0013] In another aspect of the static cone test device according to the present invention, The gripping portion is A structural frame, a pair of cam blocks that grip the rod; a pair of camshafts fixed to the pair of cam blocks, respectively; an operating handle; One camshaft is fixed to the frame, and the other camshaft is slidably attached to the frame, The other camshaft and the corresponding cam block are slid by operating the operating handle.

[0014] According to this aspect, the pair of gripping parts that grip the rod are equipped with a pair of cam blocks and a pair of corresponding cam shafts, and by operating the operating handle, one of the cam shafts and the corresponding cam block slides to grip and release the rod, thereby enabling stable gripping and release of the rod with simple and smooth operability.

[0015] In another aspect of the static cone test device according to the present invention, the other camshaft includes a first camshaft fixed to the cam block and a second camshaft that rotates in synchronization with rotation of the operating handle about a rotation axis, the first and second abutment surfaces of the first and second camshafts have complementary tapered surfaces; By rotating the operating handle, When the other camshaft slides so that the pair of camshafts move apart and the first abutment surface abuts against the second abutment surface, the pair of cam blocks release the grip of the rod, When the other camshaft slides so that the pair of camshafts approach each other and the first abutment surface and the second abutment surface are not in contact with each other, the pair of cam blocks grip the rod.

[0016] According to this aspect, one of the slidable camshafts has a first camshaft and a second camshaft with complementary tapered surfaces, and when the other camshaft slides so that the pair of camshafts move apart and the first abutment surface and the second abutment surface abut, the grip of the rod by the pair of cam blocks is released by rotating the operating handle around the rotation axis, and when the other camshaft slides so that the pair of camshafts move closer together and the first abutment surface and the second abutment surface are not abutting, the pair of cam blocks grip the rod, thereby achieving firm and stable grip of the rod by the pair of cam blocks and quick release of grip of the rod.

[0017] Another aspect of the static cone test device according to the present invention is The structure is characterized in that it is a steel segment or concrete segment that constitutes a shield tunnel, or an underground structure made of reinforced concrete or steel.

[0018] According to this aspect, since the structure (underground structure) is either a steel segment or a concrete segment (RC segment or a composite segment made of steel and concrete) that constitutes a shield tunnel, or an underground structure made of reinforced concrete or steel, static cone tests can be carried out from inside underground structures of various structural types (structural specifications) through through-holes provided in their side walls, etc., and the geology of the current ground around the constructed underground structure can be determined with high accuracy. Note that this aspect also includes underground structures made of steel-reinforced concrete.

[0019] Another aspect of the static cone test device according to the present invention is The structure is characterized in that it is a shield tunneling machine.

[0020] According to this embodiment, the static cone test is conducted through a through-hole (such as a grout hole or a through-hole for taking ground samples) provided in the main body of the shield machine constructing the shield tunnel, rather than through an underground structure that has already been constructed, making it possible to more accurately identify the geology of the current ground where the shield tunnel will be constructed.

[0021] Also, one aspect of the static cone test method according to the present invention is to A static cone test method in which a cone-shaped probe is statically pressed into the ground from inside a structure to measure ground properties, comprising: a static cone test device including a rod having the probe at its tip, a fixed portion, an extendable portion, and a gripping portion, the fixed portion being fixed to the structure; The base end side of the stretchable portion is fixed to the fixed portion, a preparation step of fixing the gripping portion that grips a part of the rod to a tip end side of the extension / contraction portion and inserting the tip end side of the rod in the press-fitting direction into a through-hole provided in the structure; The method is characterized by having an indentation measurement process in which the telescopic part is contracted while a part of the rod is gripped by the gripping part, and the probe is pressed into the ground to measure the ground characteristics of the ground.

[0022] According to this aspect, by using the static cone test device of the present invention to press a probe into the ground through a through hole provided in the side wall of an underground structure and measure the ground characteristics of the ground, it is possible to eliminate the need for large-scale preparation work resulting from the installation of a base machine, anchors, etc., and to conduct static cone tests from inside the underground structure economically and efficiently. [Effects of the Invention]

[0023] According to the static cone test device and static cone test method of the present invention, a static cone test can be performed economically and efficiently from inside an underground structure without the need for extensive preparation work. [Brief explanation of the drawings]

[0024] [Figure 1] 1A and 1B are diagrams illustrating an example of a structure to which a static cone test method according to an embodiment is applied, and an implementation situation of the static cone test method. [Figure 2] FIG. 1 is a plan view of an example static cone test apparatus according to an embodiment. [Figure 3] 3 is a view taken in the direction of an arrow III in FIG. 2, and is a side view of an example of a static cone test device according to an embodiment. [Figure 4] 4 is a view taken in the direction of an arrow IV in FIG. 2, and is a rear view of an example of a static cone test device according to an embodiment. [Figure 5A] FIG. 10 is an enlarged plan view of a gripping portion constituting the static cone test device according to the embodiment, illustrating a state in which the pressure on the rod by the cam block is released. [Figure 5B] 5B is a view taken along the arrow BB in FIG. 5A, and is a vertical cross-sectional view taken at a midpoint of the grip portion. [Figure 6A] FIG. 2 is an enlarged plan view of a gripping portion constituting the static cone test device according to the embodiment, illustrating a state in which a cam block presses a rod. [Figure 6B] 6B is a view taken along the arrow BB in FIG. 6A, and is a vertical cross-sectional view taken at a midpoint of the grip portion. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, a static cone test apparatus and a static cone test method according to an embodiment will be described with reference to the accompanying drawings. In this specification and drawings, substantially identical components are designated by the same reference numerals, and redundant description may be omitted.

[0026] [Static cone test device and static cone test method according to the embodiment] An example of a static cone test device and a static cone test method according to an embodiment will be described with reference to FIGS. 1 to 6. FIG. Here, Fig. 1 is a diagram illustrating an example of a structure to which a static cone test method according to an embodiment is applied and a state in which the static cone test method is implemented. Also, Fig. 2 is a plan view of an example of a static cone test device according to an embodiment, Fig. 3 is a side view of the example of the static cone test device according to an embodiment, taken in the direction of arrow III in Fig. 2, and Fig. 4 is a rear view of the example of the static cone test device according to an embodiment, taken in the direction of arrow IV in Fig. 2.

[0027] The static cone testing method shown in the illustration is a method of measuring ground characteristics by installing a static cone testing device 50 inside the station building structure S (an example of a structure) of an underground structure consisting of a pair of railway tunnels T with railways traveling in different directions, and the station building structure S (an example of a structure) located between the two railway tunnels T, as shown in Figure 1, and pressing a rod 10 that constitutes the static cone testing device 50 and has a probe 15 at its tip into the surrounding ground G through a through hole H provided in a part of the side wall W of the station building structure S.

[0028] In the illustrated example, the station building skeleton S is a skeleton made of reinforced concrete, and the railway tunnel T is, for example, a shield tunnel made up of steel segments. Here, the static cone test method may be a method in which a rod 10 is pressed into the ground G through a through-hole provided in a steel segment (another example of a structure) that constitutes the railway tunnel T. In addition to the illustrated example, the method may also be a method in which a rod 10 is pressed into the ground G through a through-hole such as a grout hole provided in a shield machine (another example of a structure) that is constructing a shield tunnel.

[0029] For example, a current method of investigating the surrounding ground from a shield tunneling machine involves installing an ultrasonic ground surveying device, electromagnetic wave radar, or penetrating ground surveying device on the shield tunneling machine to investigate the condition of the surrounding ground, and then constructing a shield tunnel while checking for loosening of the surrounding ground due to the excavation of the shield tunneling machine. With this survey method, it is difficult to investigate detailed data such as soil type classification when checking for loosening of the ground using, for example, electromagnetic wave radar.

[0030] In contrast, by conducting the static cone penetration test (CPT) shown in the example, it is possible to measure various ground characteristics (tip resistance, surface friction, pore water pressure, etc.) including the soil type of the surrounding ground G when investigating the surrounding ground G of the underground structure S that has already been constructed as shown in Figure 1, as well as when investigating the surrounding ground G of a shield tunneling machine in the middle of constructing the shield tunnel.

[0031] As shown in Figures 2 to 4, the static cone testing device 50 comprises a rod 10 having a probe 15 at its tip, a fixed part 20 fixed to a structure S, an extendable part 30 fixed at its base end to the fixed part 20 and extending and contracting by receiving a reaction force from the fixed part 20, and a gripping part 40 fixed at the tip side of the extendable part 30 and gripping a part of the rod 10.

[0032] 2 and 3, a groove R is constructed by chipping away the concrete in the location where a through hole H will be constructed in the side wall W of a reinforced concrete structure S, and a mounting frame F composed of H-shaped steel beams, flat steel beams, etc. is fixed around the groove R using anchors A. After that, one end of a pipe 22 constituting the fixing part 20 is positioned in the groove R, and the other part of the pipe 22 is inserted into the insertion hole Fa of the mounting frame F to maintain the positioned posture. Then, a waterproofing treatment is performed around the pipe 22 in the groove R using a waterproofing material U such as waterproof mortar, and the pipe 22 is fixed to the indoor surface of the side wall W.

[0033] Next, the mouth valve 24 and prepender 26 that similarly constitute the fixing part 20 are attached to the mouth pipe 22 to prevent water from leaking when the through hole H is constructed, and then a boring machine such as a core drill is used to construct the through hole H in the side wall W. Here, if a through hole has already been formed in the side wall W for another purpose, this through hole may be used.

[0034] In addition, the fixing part 20 in the illustrated example is equipped with a means for preventing water leakage when constructing a through hole H in the side wall W of the reinforced concrete structure S, but if the surrounding ground is not at risk of water leakage, a fixing part with a simpler configuration that does not require a mouth valve 24 or a pre-bender 26 may be applied.

[0035] Next, the immovable member 32 at the base end of the telescopic section 30 is fixed to the prepender 26 of the fixed section 20, the holding section 40 that holds a part of the rod 10 is fixed to the tip end of the telescopic section 30, and the tip end of the rod 10 in the pressing direction is inserted into the through hole H provided in the side wall W, thereby forming a static cone test device 50 inside the structure S.

[0036] The telescopic unit 30 has an immovable member 32 attached to the fixed unit 20 and having a first insertion hole 32a through which the rod 10 is inserted, a hydraulic cylinder 34 attached to the immovable member 32, and a movable member 36 attached to a piston 34a of the hydraulic cylinder 34 and sliding in the X2 direction as the piston 34a slides in the X1 direction, and having a second insertion hole 36a through which the rod 10 is inserted. As the movable member 36 slides in the X2 direction, a gripping unit 40 fixed to the movable member 36 and grips a part of the rod 10 also slides in the same manner, allowing the rod 10 to slide in the X3 direction when the rod 10 is pressed into or pulled out of the ground G.

[0037] The telescopic section 30 in the illustrated example has two hydraulic cylinders 34 arranged next to each other, and both hydraulic cylinders 34 are connected to each other by a hydraulic hose 35. The sliding of the pistons 34a in the X1 direction of both hydraulic cylinders 34 is controlled synchronously and set to have the same sliding amount.

[0038] The rod 10 inserted through the first insertion hole 32a of the immovable member 32 extends through the gap between the two hydraulic cylinders 34, is inserted into the second insertion hole 36a of the movable member 36 attached to the pistons 34a of both of the two hydraulic cylinders 34, extends further inside the gripping portion 40 attached to the movable member 36, and protrudes outside the gripping portion 40 (towards the interior of the room).

[0039] By pressing the rod 10 into the ground G using two (or more) synchronously controlled hydraulic cylinders 34, the rod 10 can be pressed into the ground G in a stable position in the desired direction even if the ground G is hard, such as gravel soil, and after measuring the ground characteristics, the rod 10 can be smoothly pulled back into the interior of the structure S in a stable position, which is preferable.

[0040] Next, the specific configuration of the gripping unit 40 will be described with reference to Figures 5 and 6. Here, Figure 5A is an enlarged plan view of the gripping unit constituting the static cone test apparatus according to the embodiment, illustrating a state in which the cam block is no longer pressing the rod, and Figure 5B is a view taken along arrow B in Figure 5A, showing a longitudinal cross-section taken at a midpoint of the gripping unit. Also, Figure 6A is an enlarged plan view of the gripping unit constituting the static cone test apparatus according to the embodiment, illustrating a state in which the cam block is pressing the rod, and Figure 6B is a view taken along arrow B in Figure 6A, showing a longitudinal cross-section taken at a midpoint of the gripping unit.

[0041] As shown in FIGS. 5A and 5B, the gripping portion 40 has a frame 41 to which a pair of cam blocks 42A, 42B and a pair of cam shafts 43A, 43B are attached.

[0042] More specifically, one cam block 42A is fixed to the frame 41 via one camshaft 43A, and the other cam block 42B is attached to the frame F so as to be freely slidable in the Y1 direction while being biased by a biasing member 47 such as a coil spring via the other camshaft 43B.

[0043] Normally, the camshaft 43B (and the cam block 42B) is biased in a direction (Y2 direction in FIGS. 5A and 5B) away from the camshaft 43A (and the cam block 42A).

[0044] The rod 10 is inserted into the gap GA between the pair of cam blocks 42. The gripping surfaces 42a, 42b of both cam blocks 42A, 42B are curved concave surfaces that can grip the outer periphery of the rod 10.

[0045] The slidable camshaft 43B has a first camshaft 44 fixed to the cam block 42B and a second camshaft 45 that rotates in synchronization with the rotation of the operating handle 46 about a rotation axis 48.

[0046] The first camshaft 44 and the second camshaft 45 are provided with first contact surfaces 44a and 44b, which are complementary tapered surfaces, respectively.

[0047] When the operating handle 46 is rotated around the pivot axis 48 and tilted, as shown in Figures 5A and 5B, the camshaft 43B slides in the Y1' direction, which is the biasing direction of the biasing member 47, so that the pair of camshafts 43A, 43B move away from each other in the Y2 direction, and the first abutment surface 44a and the second abutment surface 45a abut against each other, forming a gap GA' between the rod 10 and the gripping surfaces 42a, 42b, and the grip of the rod 10 by the pair of cam blocks 42 is released.

[0048] On the other hand, as shown in FIGS. 6A and 6B, when the operating handle 46 is rotated around the rotation axis 48 to stand up, the camshaft 43B slides in the Y1" direction against the biasing force of the biasing member 47 so that the pair of camshafts 43A, 43B move closer to each other in the Y3 direction, the first abutment surface 44a and the second abutment surface 45a are released from contact, the gripping surfaces 42a, 42b come into contact with the rod 10 in a pressed state, and the pair of cam blocks 42 grip the rod 10.

[0049] When the hydraulic cylinder 34 is driven to press the rod 10 into the ground G or when the rod 10 is pulled back from the ground G, a part of the rod 10 is gripped by the gripping portion 40 prior to these operations. In addition, when the rod 10 is sequentially added or removed to adjust the length of the rod 10, the gripping of the rod 10 by the gripping portion 40 is released prior to these operations.

[0050] The above is a specific configuration of the static cone test device 50. In the static cone test method, the static cone test device 50 is installed inside the structure S on its side wall W (preparation step).

[0051] Next, the hydraulic cylinder 34 is driven, for example, to retract the extended piston 34a, add the rod 10 as necessary, and drive the hydraulic cylinder 34 in the same manner. This is repeated to press the rod 10 in, causing the probe 15 to reach a predetermined position in the ground G around the structure S, and the ground characteristics of the ground G are measured during this pressing process and at this reached position (pressing measurement process).

[0052] According to the static cone test apparatus 50 shown in the figure and the static cone test method using the same, the static cone test apparatus 50 is used to press the probe 15 into the ground G through a through hole H provided in the side wall W of the underground structure S, and the ground characteristics of the ground are measured, thereby eliminating the need for large-scale preparation work due to the installation of a base machine, anchors, etc., and making it possible to conduct static cone tests from inside the underground structure S economically and efficiently.

[0053] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0054] 10: Rod 15: Probe 20: Fixed part 22: Mouth tube 24: Mouth valve 26: Prepender 30: Telescopic part 32: Immovable parts 32a: First insertion hole 34: Hydraulic cylinder 35: Hydraulic hose 36: Movable parts 36a: Second insertion hole 40: Grip part 41: Structural frame 42, 42A, 42B: Cam block 43, 43A, 43B: Camshaft 44: First camshaft 44a: First contact surface 45: Second camshaft 45a: Second contact surface 46: Operating handle 47: biasing member 48: Rotation axis 50:Static cone test equipment G: Ground (surrounding ground) T: Tunnel (railway tunnel) S: Structures (underground structures, station building frames) W: Side wall H: Through hole R: Mouth U: Water-stopping material F: Mounting frame GA: Interval GA': Gap

Claims

1. A static cone test device that measures ground characteristics by statically pressing a cone-shaped probe into the ground from inside a structure, comprising: a rod that is inserted into a through-hole provided in the structure and has the probe at its tip; a fixing portion fixed to the structure; an expandable portion whose base end side is fixed to the fixed portion and expands and contracts by receiving a reaction force from the fixed portion; a gripping portion fixed to a tip side of the extension / contraction portion and gripping a part of the rod; A static cone test device characterized in that the telescopic part contracts while the gripping part grips a part of the rod, thereby pressing the probe at the tip of the rod into the ground.

2. The stretchable portion is a stationary member attached to the fixed portion and including a first insertion hole through which the rod is inserted; a hydraulic cylinder attached to the stationary member; a movable member attached to a piston of the hydraulic cylinder, sliding together with the piston, and having a second insertion hole through which the rod is inserted; 2. The static cone test device of claim 1, wherein the gripping portion is attached to the movable member.

3. The gripping portion is A structural frame, a pair of cam blocks that grip the rod; a pair of camshafts fixed to the pair of cam blocks, respectively; an operating handle; One camshaft is fixed to the frame, and the other camshaft is slidably attached to the frame, 2. The static cone test device according to claim 1, wherein the other camshaft and the corresponding cam block are slid by operating the operating handle.

4. the other camshaft includes a first camshaft fixed to the cam block and a second camshaft that rotates in synchronization with rotation of the operating handle about a rotation axis, the first and second abutment surfaces of the first and second camshafts have complementary tapered surfaces; By rotating the operating handle, When the other camshaft slides so that the pair of camshafts move apart and the first abutment surface abuts against the second abutment surface, the pair of cam blocks release the grip of the rod, 4. The static cone test device according to claim 3, wherein the pair of cam blocks grip the rod when the other camshaft slides so that the pair of camshafts approach each other and the first abutment surface and the second abutment surface are not in contact with each other.

5. 4. The static cone test device according to claim 1, wherein the structure is a steel segment or a concrete segment constituting a shield tunnel, or an underground structure made of reinforced concrete or steel.

6. 4. A static cone test apparatus according to any one of claims 1 to 3, wherein the structure is a shield tunneling machine.

7. A static cone test method in which a cone-shaped probe is statically pressed into the ground from inside a structure to measure ground properties, comprising: a static cone test device including a rod having the probe at its tip, a fixed portion, an extendable portion, and a gripping portion, the fixed portion being fixed to the structure; The base end side of the stretchable portion is fixed to the fixed portion, a preparation step of fixing the gripping portion that grips a part of the rod to a tip end side of the extension / contraction portion and inserting the tip end side of the rod in the press-fitting direction into a through-hole provided in the structure; a press-in measurement process for contracting the extension / contraction section while holding a portion of the rod with the holding section, and pressing the probe into the ground to measure the ground characteristics of the ground.

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