JP2009133163A - Percussive penetration testing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a percussive penetration testing apparatus for investigating a bed structure at a hammering point and the strength of a ground by penetrating a rod into the ground by hammering. <P>SOLUTION: This percussive penetration testing apparatus 1 comprises a hammering unit 2 having a hammer 44, a penetration rod 2 penetrated into the ground by the hammer 44, a lift 12 following up the penetration rod 2 and applying a predetermined load to the penetration rod 2, a base unit 10 having a drive source 16 and lifting the lift 12 along a column, a load changing means 14 for changing the load to the lift 12 for changing the load applied to the penetration rod 2, a penetration amount detection means 17 for detecting the penetrated amount of the penetration rod 2 for each hammering by the hammer 44, and a control means 50 for controlling the hammering unit 20 and the load changing means 14 according to the penetration amount for each hammering detected by the penetration amount detection means 17. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a striking penetrating test apparatus for striking a rod and penetrating into the ground and investigating the stratum structure and ground strength at that point.

  Conventionally, in ground surveys such as planned land construction sites, a so-called Swedish sounding test in which three types of weights are loaded on the rod and self-settled, and when the self-sink stops, the test rod is driven to rotate without further load. , Automatic ram sounding in which a hammer is dropped freely and a test rod is struck and penetrated into the ground for testing, and a test method similar to this automatic ram sounding test, which is a mini ram sounding with a reduced size of this test equipment Tests are known.

  The Swedish sounding test is a test for measuring the in-situ position by penetration with a predetermined load and rotation penetration, and measuring the static penetration resistance of the ground such as a so-called residential area to determine the hardness and softness of the soil. The purpose is to grasp the ground condition of the construction site. Since this test method is easy and quick to operate, the test method is widely used as a ground survey method in a detached residential area, particularly for a relatively shallow ground having a depth of about 10 m.

  On the other hand, the automatic ram sounding test is known as a dynamic cone penetration test. As a test method, the rod is penetrated into the ground by dropping a hammer having a predetermined weight from a predetermined height. Measure the number of hits required to penetrate 20cm into the ground. The N value is obtained from the number of hits, and the hardness of the ground is judged from the N value. As an apparatus that automates this test, a self-propelled impact penetrating test apparatus shown in Patent Document 1 (hereinafter, this self-propelled impact penetrating test apparatus is simply referred to as an impact penetrating test apparatus) is known. This impact penetrating test apparatus has a self-propelled machine that can be operated by an operator, and a leader that guides the hammer device so as to be movable up and down is attached to the impact penetrating test apparatus perpendicularly to the ground. A test rod is attached to the lower portion of the hammer device, and the tip of the test rod penetrates into the ground when the hammer strikes the rear end of the test rod. Moreover, in this impact penetration test apparatus, the number of impacts per 20 cm penetration is automatically displayed via the control device, and it is not necessary for the operator to count the impact number. There is an effect that a count error does not occur.

JP 2003-213661 A

  In the impact penetration test apparatus, since the impact is continued until the rod penetrates 20 cm, there is a problem that work efficiency is poor because the impact is continued even when reaching a hard formation that cannot be penetrated. In addition, when reaching a soft formation where the rods are self-sinking, there is no means for discriminating this boundary, and there is a problem that the precise formation of the ground cannot be determined.

For the purpose of solving the above-mentioned problems, an impact penetrating test apparatus according to the present invention includes an impact unit that guides a hammer so that the hammer can be moved up and down, an intrusion rod that penetrates into the ground by being hit by the hammer, and An elevating base that guides the penetrating rod and applies a predetermined load to the penetrating rod following the penetrating rod, a drive unit, and a base unit that raises and lowers the hoisting base along the column, and driving of the base unit A load changing means which is connected to a drive shaft of a source and can change a load applied to the lifting platform in order to change a load applied to the penetrating rod; and penetration of the penetrating rod for each impact by the hammer A penetration amount detecting means capable of detecting the amount, and a control for controlling the hitting unit and the load changing means according to the penetration amount for each hit detected by the penetration amount detecting means. Characterized in that it comprises a stage.
2. The impact penetration test according to claim 1, wherein when the penetration amount of one impact detected by the penetration amount detection unit is 0, the control unit controls to stop the impact by the impact unit. 3. apparatus.

  The control unit controls to stop the hit by the hit unit when the penetration amount of one hit detected by the penetration amount detecting means exceeds a preset limit penetration amount, and the penetration unit The load changing means is controlled to change the load applied to the rod.

  Furthermore, the control unit includes a display unit that displays a penetration amount for each hit detected by the penetration amount detection means. The load changing means is preferably a powder clutch.

  In the impact penetration test apparatus of the present invention, the penetration amount of the penetration rod for each impact is detected by the penetration amount detection means. For example, when reaching a hard formation that cannot be penetrated, the penetration amount is detected as 0. Therefore, if the batting is stopped immediately, the extra batting can be reduced. In addition, if the intrusion amount exceeds a preset value, there is a possibility of a self-settlement formation, and if the strike is stopped immediately, it is possible to quickly detect whether it is a self-settlement formation, so work efficiency is improved. To rise.

  Further, by displaying the penetration amount for each impact detected by the penetration amount detection means on the display unit of the control unit, the operator can grasp the formation status of the inspection ground at any time.

  Furthermore, in the impact penetrating test apparatus of the present invention, since the load applied to the penetrating rod can be changed, the load due to the mass of the lifting platform or the striking unit is not applied to the penetrating rod. Only the minimum load necessary to make the lifting platform follow in response to the penetration penetration of the penetration rod into the ground is applied. Therefore, even when the test ground is soft, it is possible to prevent the penetration rod from penetrating into the ground by the load due to the mass of the striking unit, and it is possible to accurately determine whether or not it is a self-sinking ground.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes an impact penetrating test apparatus, which is configured by mounting an impact unit 20 on a base unit 10. The base unit 10 has a first support column 11 erected on a stand 18, and an elevator platform 12 is guided on the first support column 11 so as to be movable up and down. A sprocket 13 is rotatably provided on the lifting platform 12 so as to be located on the back side of the first support column 11. The sprocket 13 extends linearly in the vertical direction on the back surface of the first support column 11. It meshes with the attached chain member 11a. Further, as shown in FIG. 2, the sprocket 13 is connected to a unit lifting / lowering motor 16 through a clutch mechanism including a powder clutch 14 and a one-way clutch 15 as an example of load changing means. It is configured to be rotated by receiving 16 driving.

  When the unit lifting / lowering motor 16 is driven to rotate the sprocket 13 in the direction in which the lifting / lowering platform 12 is raised (hereinafter, this driving is referred to as positive driving), the one-way clutch 15 is driven by the sprocket 13. On the contrary, when the unit raising / lowering motor 16 is driven (hereinafter, this driving is referred to as reverse driving), it is idled.

  The powder clutch 14 is a clutch that can stably generate a rotational resistance corresponding to the excitation voltage by exciting the enclosed magnetic powder. The powder clutch 14 is interposed between the drive shaft on the unit lift motor 16 side and the drive shaft on the sprocket 13 side, and is configured to control the torque transmitted from the unit lift motor 16 side to the sprocket 13 side. Yes.

  As shown in FIG. 1, the hitting unit 20 includes an elevator unit 30 and a hammer unit 40.

  The elevator unit 30 includes a table 31 that is detachably connected and fixed on the elevator 12 of the base unit 10, and a second column 32 is erected on the table 31. The second support column 32 has a hollow central portion in the longitudinal direction, and sprockets (not shown) are rotatably installed above and below the hollow portion (not shown). An annular endless chain 35 is wound around and meshed with these sprockets as an example of an endless circulation moving member. The upper sprocket is rotatably supported by the second support column 32, and the lower sprocket is rotated by driving a hammer operation motor 36 provided on the table 31. Thereby, the endless chain 35 is configured to be circulated and fed by the drive of the hammer operating motor 36. A locking member (not shown) is integrally fixed to a predetermined position of the endless chain 35 so as to protrude to a predetermined position of the endless chain. A release member (not shown) is fixed to the second support column 32 so as to be positioned on an upward movement path of a claw 48 of the hammer 44 described later in detail.

  As shown in FIGS. 3 (a), 3 (b) and 3 (c), the hammer unit 40 is a hollow which can be inserted into the table 31 through a cylinder holder 31a and penetrates the lifting platform 12. A shaft-shaped rod cylinder 41 is provided, and the shaft-shaped penetrating rod 2 is inserted and guided in the rod cylinder 41. A knocking head 42 is attached to an upper portion of the rod cylinder 41. The knocking head 42 is formed so as to integrally cover an upper end portion of the penetrating rod 2, and the penetrating rod 2 is directly hit by a hammer 44 described later. This is to prevent the penetration rod 2 from being damaged. On the other hand, a load receiving member 45 is attached to the lower portion of the rod cylinder 41 so as to cover the peripheral surface, and the load receiving member 45 moves up and down integrally with the rod cylinder 41 and the lifting platform. 12 is configured to receive the loads of all the units mounted on it.

  Further, as shown in FIG. 1, the hammer unit 40 includes a guide rail 43 that extends in parallel with the second support column 32 with the rod cylinder 41 interposed therebetween. A hammer 44 is guided on the guide rail 43 so as to be movable up and down, located above the knocking head 42. The hammer 44 includes a claw 48 that can be engaged with a locking member fixed to the endless chain 35, and rises as the endless chain 35 is circulated. Thereafter, when the hammer 44 rises and the claw 48 comes into contact with the release member, the engagement between the claw 48 and the locking member is released, and the hammer 44 falls due to its own weight and strikes the knocking head 42. Is configured to do.

  A control unit 50 for controlling the operation of the impact penetrating test apparatus includes a penetration amount detection unit 52 connected to the arithmetic processing unit 51, a lifting motor driving unit 53, a hammer operation motor driving unit 54, and a powder clutch control. A unit 55, a storage unit 56, a display unit 57, and an input unit 58 are provided. The penetration amount detection unit 52 is configured to detect the rotation angle of the rotating sprocket 13 by the rotary encoder 17 which is an example of the penetration amount detection means, and calculate the penetration amount of the penetration rod 2 therefrom. When the penetration amount detected by the penetration amount detection unit 52 is 0, the arithmetic processing unit 51 is configured to send a stop command signal to the hammer operation motor drive unit 54. By this stop command signal, the power supply to the hammer operation motor 36 is cut off, the motor 36 is stopped, and the hammer unit 40 stops hitting.

  Further, the storage unit 56 stores in advance the load current value applied to the powder clutch 14 input from the input unit 58 or the limit penetration amount of the penetration rod 2 per one hit, and during the test, one hit When the penetration amount of the hit penetration rod 2 exceeds the limit penetration amount, the arithmetic processing unit 56 sends a stop command signal to the hammer operation motor drive unit 54 and excites the powder clutch control unit 55 with excitation. A command signal is transmitted. By this stop command signal, the power supply to the hammer operating motor 36 is cut off and the hammer unit 40 is stopped from hitting, while the powder clutch 14 is excited so as to exert a predetermined clutch force, and the elevator 12 and this The sprocket 13 that is about to rotate in the descending direction due to the mass of the hammer unit 40 or the like placed on the sprocket 13 is always subjected to a rotational load, and the load applied to the penetrating rod 2 is reduced.

Next, the operation of the impact test apparatus will be described.
This impact penetrating test apparatus 1 is a test method similar to the automatic ram sounding test outlined in Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-213661), and the test apparatus is reduced in size. The penetration test is performed by the mini-ram sounding method to be performed, and the hammering force is applied to the penetration rod 2 by hitting the knocking head 42 with the hammer 44, thereby penetrating the penetration rod 2 into the ground. . Then, the number of hits required for the penetrating rod 2 to penetrate 20 cm into the ground is measured, an N value is calculated therefrom, and the hardness of the ground is determined from the N value. The formula for calculating the N value is
For sandy ground: N = Ndm / 2
For viscous ground: N = (Ndm / 2) −0.16 Mv
N: Corrected hit count Ndm: Measured hit count Mv: Rotational torque (N · m)
It is. Here, with respect to the rotational torque Mv, every time the penetrating rod 2 penetrates 20 cm into the ground, the impact is temporarily stopped, and the torque that starts rotating by manually turning the penetrating rod 2 is measured.

  In order to perform the penetration test, the actual impact penetration test apparatus 1 is installed at the test position. First, the control unit 50 positively drives the unit lifting motor 16 to raise the lifting platform 12, and then the hammer lifting motor 36 is connected to an endless chain. 35 is driven so that the side of the hammer 44 is raised, the locking member is brought into contact with the claw 48 of the hammer 44, and the hammer 44 is appropriately raised to a position where the claw 48 does not contact the release member. Subsequently, the penetrating rod 2 is placed on the ground surface so that the center of the cone 4 is aligned with the center of a hole of a guide (not shown) attached to the stand 18, and the unit lifting motor 16 is driven again to reversely lift the lifting platform 12. The penetrating rod 2 is inserted into the rod cylinder 41 while lowering. The penetrating rod 2 inserted into the rod cylinder 41 abuts on the knocking head 42 when the lifting platform 12 is lowered, and pushes the knocking head 42 and the rod cylinder 41 together upward. In this way, the lifting platform 12 is lowered until the rod cylinder 41 is completely pushed up (reverse driving of the unit lifting motor 16 is continued). Since the unit elevating motor 16 includes a lock mechanism that fixes the drive shaft so as not to rotate when driving is stopped, the elevating platform 12 is held at the lowered position.

  Next, the hammer operating motor 36 is driven so that the hammer 44 side of the endless chain 35 is lowered, whereby the hammer 44 is lowered and placed on the knocking head 42. Then, this position is set as the test origin (penetration amount 0 mm) in the storage unit 56 of the control unit 50, and a predetermined limit penetration amount and a load current value applied to the powder clutch 14 are set. The forward / reverse driving of the unit raising / lowering motor 16 and the hammer operation motor 36 so far is performed by the operator operating the manual drive buttons of the respective motors provided in the control unit 50. Thereafter, each motor is driven by automatic control by the control unit 50 except when the penetrating rod 2 is added.

  Subsequently, when a test start start signal is input by a test start button provided in the control unit 50, the unit elevating motor 16 is reversely driven and the one-way clutch 15 is idled. Further, the excitation of the powder clutch 14 is released, and the rotational load of the sprocket 13 is released. As a result, the sprocket 13 becomes rotatable, and the penetrating rod 2 is subjected to a load due to the mass of the striking unit or the like equipped on the lifting platform 12. Here, the powder clutch 14 is excited so as to exert a predetermined clutch force by the load current value set in the storage unit 56 in advance, and tries to rotate in the direction in which they are lowered by the mass of the lifting platform 12 or the like. A rotating load is constantly applied to the sprocket 13 to reduce the load applied to the penetrating rod 2. For example, the powder clutch 14 is excited so as to generate a rotational load torque (clutch force) that is slightly lower than the shaft torque generated when the sprocket 13 is rotated by a load due to the mass of the lifting platform 12 or the like. As a result, the penetrating rod 2 is not subjected to a load due to the mass of the striking unit 20 or the like equipped on the lifting platform 12, and the lifting platform 12 is caused to follow in accordance with the striking penetration of the penetrating rod 2 described below into the ground. Only a necessary minimum load (for example, a load of 9.8 N corresponding to a mass of 1 kg) is applied. In this way, even when the test ground is soft, it is possible to prevent the penetrating rod 2 from penetrating into the ground by a load due to the mass of the striking unit 20 or the like.

  Subsequently, the hammer operation motor 36 is driven, and the endless chain 35 and the locking member are circulated and fed together so as to move upward on the front surface side (hammer 44 side). When the hammer 44 is brought into contact with the release member and still rises, the claw that is in contact with the release member rotates toward the hammer 44 and is released from the locking member. The hammer 44 falls by its own weight and strikes the knocking head 42. At this time, the penetrating rod 2 and the rod cylinder 41 holding the rod descend from the position shown in FIG. 3A to the position shown in FIG. 3B, and the penetrating rod 2 penetrates into the ground. At this time, as shown in FIG. 3 (b), the penetrating rod 2 is loaded by the mass of the lifting platform 12, the hitting unit 20, and the like as described above. As shown in c), the penetrating rod 2 can be integrally lowered following the penetration. Thereafter, the hammer 44 hitting the knocking head 42 is again locked by the locking member that circulates again and rises again.

  As described above, the endless chain 35 is circulated and fed, so that the hammer 44 strikes back and the penetrating rod 2 penetrates into the ground. The penetration amount of the penetration rod 2 is determined from the signal of the rotary encoder 17 by detecting the rotation angle of the sprocket 13 by the rotary encoder 17. Further, the number of hits is counted based on the signals of the proximity sensors detected by the proximity sensors (not shown) provided at the ascending position and the descending position of the hammer 44, respectively. For example, if the ascending proximity sensor is turned on / off within a predetermined time, and then the descending proximity sensor is turned on / off within a predetermined time, one hit is counted. The control unit 50 obtains the number of hits required for each time the penetrating rod 2 penetrates 20 cm into the ground in this way, and stores this in the storage unit 56. Further, every time the penetrating rod 2 penetrates 20 cm, the hammer operation motor 36 is stopped to stop the hitting, and the rotational torque Mv measured manually is input to the input unit 58 of the control unit 50. It is stored in the storage unit 56. In addition, in the impact penetration test apparatus 1 of the present invention, in addition to the number of impacts per 20 cm penetration, the penetration amount per impact is calculated and stored, and displayed on the display unit 57.

In this hitting penetration test apparatus 1 having such a configuration, it is possible to determine finer ground softness with a width of 20 cm or less, and the operator simply looks at the display unit 57 of the control unit 50 to check the ground condition. Can know. Further, when the control unit 50 is configured to reach a hard ground that cannot be hit and the penetration amount per hit is detected as 0, the hit penetration test is automatically stopped at this time, and the operator It is possible to quickly know that it has reached an impossible hard ground, and it is possible to shorten the test time. Furthermore, even when the self-sinking formation is reached and the penetration amount per impact exceeds a preset limit penetration amount, the control unit 50 can be switched from the impact penetration test to the self-settlement penetration test. Therefore, the impact test and the penetration test can be performed in series, and the test time can be shortened.

It is a front side perspective view of the impact penetration testing apparatus concerning the present invention. It is an AA principal part expanded sectional view of FIG. It is a BB line principal part expanded sectional view of FIG. 1, and is operation | movement explanatory drawing of the impact penetrating test apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blow penetration test apparatus 2 Penetration rod 4 Cone 10 Base unit 11 1st support | pillar
11a Chain member 12 Lifting base 13 Sprocket 14 Powder clutch 15 One-way clutch 16 Unit lifting motor 17 Rotary encoder 18 Stand 19 Guide 20 Strike unit 30 Elevator unit 31 Table 31a Cylinder holder 32 End column 35 Endless chain 36 Hammer operating motor 40 Hammer unit 41 Rod cylinder 42 Knocking head 43 Guide rail 44 Hammer 45 Load receiving member 48 Claw 50 Control unit 51 Calculation processing unit 52 Penetration amount detection unit 53 Lift motor drive unit 54 Hammer operation motor drive unit 55 Powder clutch control unit 56 Storage unit 57 Display 58 Input section

Claims (5)

A striking unit that guides the hammer so that it can be raised and lowered,
A penetrating rod that penetrates into the ground after being hit by this hammer,
A lifting platform that guides the penetrating rod so as to be freely inserted and follows the penetrating rod and applies a predetermined load to the penetrating rod;
A base unit that includes a drive source and moves the lifting platform up and down along the support;
A load changing means that is connected to a drive shaft of a drive source of the base unit and is capable of changing a load applied to the lifting platform in order to change a load applied to the penetrating rod;
A penetrating amount detecting means capable of detecting the penetrating amount of the penetrating rod for each hit by the hammer, and the striking unit and the load changing means according to the penetrating amount detected for each hit by the penetrating amount detecting means; A striking penetration testing device comprising a control means for controlling the impact.   2. The impact penetration test according to claim 1, wherein when the penetration amount of one impact detected by the penetration amount detection unit is 0, the control unit controls to stop the impact by the impact unit. 3. apparatus.   The control unit controls to stop the hitting by the hitting unit when the penetration amount of one hit detected by the penetration amount detecting means exceeds a preset limit penetration amount, and to the penetration rod. 2. The impact penetrating test apparatus according to claim 1, wherein the load changing means is controlled to change the applied load.   The impact penetrating test apparatus according to claim 1, wherein the control unit includes a display unit that displays an intrusion amount for each impact detected by the intrusion amount detecting unit.   The impact penetrating test apparatus according to any one of claims 1 to 4, wherein the load changing means is a powder clutch.

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