JP5173731B2 - Penetration rod, penetration tester and penetration test method using the same - Google Patents

Description

The present invention relates to a penetrating rod for detecting a rotational load torque of a screw point by rotating a penetrating rod composed of a rod and a screw point arranged at the tip thereof into the ground, and a penetrating test machine and penetrating using the penetrating rod. It relates to the test method.

  Conventionally, a Swedish sounding test method shown in Non-Patent Document 1 is known as one of methods for determining the soil quality of the ground. This test measures the hardness of the ground by measuring the resistance when the screw point attached to the tip of the rod penetrates the ground. The penetration method consists of a load stage in which six stages of loads are applied to the maximum 1KN with the built-in weight and self-sinking with only the load, and when the rod does not penetrate even at the maximum load of 1KN, the rod or screw point is set under that load. It is performed in two stages, a rotation stage in which rotation is performed by rotating. The measurement items for the penetration resistance are the load (Wsw) when the screw point penetrates a predetermined depth in the load stage, and the half rotation number (Nsw) of the screw point converted per penetration amount in the rotation stage. This half rotation number is the number of rotations counted as one screw point rotation.

  As a testing machine that automates the above-mentioned Swedish sounding test, there is one shown in Patent Document 1 (Japanese Patent Laid-Open No. 9-111745). This penetration testing machine has a lifting platform that can be lifted and lowered along a column by driving a lifting motor, and a chuck is disposed on this lifting platform. The chuck is configured to rotate by being driven by a chuck motor, and a rod is rotatably held integrally with the chuck. A screw point is attached to the tip of this rod, and the penetration test is performed by inserting this screw point into the ground.

  A sprocket is rotatably provided at the rear part of the lifting platform. The sprocket is always meshed with a chain member arranged on the support column, and the elevator is moved up and down as the sprocket rotates along the chain member. Further, the sprocket is braked by the operation of the powder brake, and the load applied to the rod and screw point is changed by controlling the load applied to the lifting platform.

  As the penetrating rod consisting of the rod and screw point penetrates into the ground, the penetrating speed of the penetrating rod changes according to the soil quality. Therefore, rotation is applied / stopped so that the penetrating speed is as constant as possible. Intrusion conditions are changed, such as load changes. Test data is acquired by the control unit when this penetration condition is changed and every time the penetration rod penetrates a predetermined depth.

  The test data includes the penetration amount of the penetrating rod from the position where the previous test data was acquired, the half-rotation number of the penetrating rod in the meantime (the number of revolutions counted as one revolution of the penetrating rod as 2), and the load value therebetween. If the ground is firm, the number of half revolutions increases, so the ground strength at each penetration depth can be known from this half revolution number, and the ground strength of the land can be examined.

Japanese Industrial Standard A1221 Swedish Sounding Test Method JP-A-9-111745

However, in the above-described penetration rod, and the penetration tester and the penetration test method using the penetration rod, since a resistance in the ground is added to the rod during the rotation of the rod, it is based on the resistance added only to the screw point. It was difficult to calculate test data. In this case, the hardness of the formation where the screw point has reached should be measured, but in reality, it is affected by the upper layer than the formation where the screw point has reached, and accurate test data cannot be obtained. It was.

The penetrating rod of the present invention has been created in view of the above problems, and is composed of a rod and a screw point attached to the tip of the rod, and penetrating into the ground by penetrating the screw point into the ground during a penetrating test. The rod has a connector for connecting the rod and the screw point, and the connector has a double tube structure including an outer tube to which the screw point is connected and a rod to which the rod is connected. The outer tube and the rod are normally engaged with each other in the circumferential direction to rotate integrally. On the other hand, when the rod is pulled up and moved in the axial direction, the circumferential engagement is released and the rod is released. Only is configured to rotate.

Further, the penetration testing machine of the present invention was created in view of the above problems, and consists of a rod and a screw point attached to the tip of the rod, and a penetration rod that penetrates the ground by piercing the screw point into the ground. A lifting platform that can be moved up and down along a support; a lifting unit that lifts and lowers the lifting table; a chuck that is attached to the lifting table and rotatably holds the penetrating rod; and that rotates the penetrating rod. A double-pipe structure comprising a chuck motor, a torque sensor for detecting the rotational load of the penetrating rod, an outer tube to which the screw point is connected, and a bar to which the rod is connected is formed. The rods are usually engaged with each other in the circumferential direction and rotate integrally. On the other hand, when the rod is pulled up and moved in the axial direction, the circumferential engagement is released. When the rod and the screw point are connected, and when the rod and the screw point are connected, the connection between the rod and the screw point is released. And a control unit that measures the rotational load of the rod and calculates the rotational load of the screw point by subtracting the rotational load of the rod from the rotational load of the rod and the screw point.

  Further, the penetration test method of the present invention was also created in view of the above-mentioned problems, and a screw point is formed by penetrating and rotating a penetration rod composed of a rod and a screw point arranged at the tip of the rod. In the penetration test to measure the rotational load of the rod, after measuring the rotational load of the rod and screw point, measure the rotational load of the rod and subtract the rotational load of the rod from the rotational load of the rod and screw point. The rotational load is calculated.

  In the penetration test method, when measuring the rotational load of the rod and the screw point, both the rod and the screw point are rotated. On the other hand, when measuring the rotational load of the rod, the screw point is not rotated and only the rod is rotated. It is characterized by rotating.

In the penetrating rod of the present invention, and the penetrating test machine and penetrating test method using the penetrating rod, the rotational load of the penetrating rod composed of the rod and the screw point is measured during the penetrating test, while only the rotational load applied to the rod is measured. It is also configured as follows. Therefore, by reducing the rotational load of the rod from the rotational load of the rod and screw point, it is possible to obtain only the rotational load applied to the screw point, so it is possible to accurately test the ground hardness in each layer. .

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In FIG.
Reference numeral 1 denotes a penetration tester, which is a lifting platform 3 that can be moved up and down along the support column 2, a chuck 10 that is rotatably provided on the lifting platform 3, a chuck motor 11 that rotationally drives the chuck 10, It has a penetrating rod 4 composed of a rod 8 held by a chuck 10 and a screw point 7 attached to the tip thereof, and a lifting unit 40 that lifts and lowers the lifting platform 3 along the column 2.

  The support column 2 is erected on a leg portion 5, and a chain member 6 as an example of a guide path is arranged and fixed on a straight line on the back surface thereof. The chain member 6 is engaged with a sprocket 44 of an elevating unit 40 which will be described in detail later.

  As shown in FIG. 2, the chuck 10 includes a hollow sleeve 12 that is rotatably disposed on the lifting platform 3 and that is supported so that the rod 8 can be inserted and rotated. The hollow sleeve 12 is provided with a rigid ball 13 that engages with a long groove 8 a formed in the rod 8, and a sprocket 14 is provided at the lower portion of the hollow sleeve 12. The rigid sphere 13 is supported by a slide sleeve 16 always biased by a spring 15 at a position protruding from the hollow hole portion 12a of the hollow sleeve 12, and engages with the long groove 8a of the rod 8 in this state. When the slide sleeve 16 is pushed down against the bias of the spring 15, the hard sphere 13 becomes operable and the rod 8 can be released.

  A second output shaft 26 is connected to the output shaft 11 a of the chuck motor 11 via a planetary gear mechanism 20. A sprocket 17 is fixed integrally to the lower part of the second output shaft 26, and the sprocket 17 and the sprocket 14 provided at the lower part of the hollow sleeve 12 are connected by winding an annular chain 18. A proximity sensor (not shown) that detects the passage of teeth when the sprocket 14 rotates and is turned on / off is attached to a position facing the teeth of the sprocket 14 on the chuck side. The proximity sensor signal is acquired by the control unit 50. The control unit 50 is configured to calculate the half rotation number of the penetrating rod 4 and to control the driving of the chuck motor 11.

  The planetary gear mechanism 20 is accommodated in a flange 19, and the chuck motor 11 is disposed above the flange 19. Further, as shown in FIG. 3, the planetary gear mechanism 20 is engaged with a sun gear 21 that is attached to rotate integrally with the output shaft 11a of the chuck motor 11, and is engaged with the sun gear 21. A plurality of planetary gears 22, 23, and 24 that revolve around the sun gear 21 while rotating around the sun gear 21, and an internal gear 25 that is formed in a ring shape and has internal teeth. The internal gear 25 is configured such that its internal teeth mesh with the plurality of planetary gears 22, 23, 24 to guide the rotation and revolution of the planetary gears 22, 23, 24. The second output shaft 26 is rotatably attached to the lower surfaces of the planetary gears 22, 23, 24 together with the planetary gears 22, 23, 24, and the second output shaft 26 and the chuck motor 11 are connected to each other. The output shaft 11a is disposed on the same axis. Carriers 27, 28, and 29 are interposed between the planetary gears 22, 23, and 24, respectively. These carriers 27, 28, and 29 are integrally formed with the second output shaft 26.

  On the inner peripheral surface of the flange 19, beams 31 and 32 facing inward are formed integrally with the flange, and these beams 31 and 32 are positioned so as to face each other with the internal gear 25 interposed therebetween. Yes. The internal gear 25 is fixed to the beams 31 and 32 so that they do not rotate with the rotation of the planetary gears 22, 23, and 24. The internal gear 25 receives a rotational reaction force from the penetrating rod 4 on the side surface of the beam 31, and strain gauges 33 and 34 are attached so that the rotational reaction force faces each other in the direction in which the rotation reaction force acts on the beam 31. Similarly, strain gauges 35 and 36 are also attached to the other beam 32. The total of four strain gauges and two beams constitute the torque sensor 30, and these four strain gauges are incorporated in a Wheatstone bridge circuit. These four strain gauges 33, 34, 35, 36 are configured to detect a strain corresponding to the torsion of the beams 31, 32 as an electric signal, and these strain gauges 33, 34, 35, 36 are configured. From the above signal, the control unit 50 measures the rotational load torque of the screw point 7 and the rod 8 or the rotational load torque of the rod 8. The torque sensor 30 employs a so-called 4-active cage method in which a resistance value is measured by a whistle bridge circuit in which the four strain gauges 33, 34, 35, and 36 are incorporated.

  As shown in FIG. 4, the elevating unit 40 includes an elevating motor 41 that rotationally drives the sprocket 44, and brake means 42 that controls the rotation of the sprocket 44. The sprocket 44 is connected to the elevating motor 41 via the one-way clutch 43 and the brake means 42, and the one-way clutch 43 acts to raise and lower the sprocket 44 in the direction to raise the elevator 3. These are transmitted to the sprocket 44 when the motor 41 is driven. On the other hand, when the elevating motor 41 is driven so as to rotate the sprocket 44 in the reverse direction, the one-way clutch 43 is idled. For this reason, when the lifting / lowering motor 41 is reversely driven in a state where the screw point 7 is in contact with the ground, the penetrating rod 4 is loaded with a load due to the mass of the lifting platform 3 or the like. This load can be freely changed from 0 N to 1 KN by changing the force with which the brake means 42 brakes the sprocket 44. The brake means 42 is preferably a powder clutch or a powder brake.

  As shown in FIGS. 5 (a) and 5 (b), the penetrating rod 4 is composed of a rod 8 and a screw point 7 attached to the tip of the rod 8 via a connector 60, and the screw point 7 is pierced into the ground. It is configured to penetrate inside. The connector 60 includes a rod 61 that is connected to the tip of the rod 8 by a stud bolt B and rotates integrally with the rod 8, and a hollow outer tube 62. The bar 61 is provided with an abutting portion 61a. As shown in FIG. 5A, the outer tube 62 has an upper end and an abutting portion of the bar 61 from above. The bar 61 is inserted so as to engage with 61a. Further, a cap 63 is attached to the lower end of the outer tube 62 so as to be rotatable integrally with the outer tube 62 so that the upper portion of the cap 63 is inserted into the outer tube 62, while a screw point is attached to the lower end of the cap 63. 7 is rotatably attached integrally with the cap 63 by a stud bolt B.

  A protrusion 62 a is formed at the upper end of the outer tube 62, while a groove 61 b that can be engaged with the protrusion 62 a is formed in the abutting part 61 a of the bar 61. In a state where the protrusion 62a is inserted into the groove 61b of the abutting part 61a, when a rotational force is applied to the rod 8, the protrusion 62a and the groove 61b are engaged, and the rod 8 is When a force in the upward direction is applied, as shown in FIG. 5B, the engagement between the bar 61 and the outer tube 62 is released, and the abutting portion 61 a of the bar 61 has the outer tube 62. Leave from the top. Specifically, as shown in FIG. 6A, when a rod 61 and the outer tube 62 are engaged, when a rotational force is applied to the rod 8, the rod 8 and the screw point 7 are used. When the rod 8 and the outer tube 62 are disengaged and a force is applied to the rod 8 in the rotational direction as shown in FIG. 6B, the rod 8 rotates. Thus, the screw point 7 is configured not to rotate.

  Further, a bullet-like restricting portion 62b is formed in the lower portion of the hole of the outer tube 62, and a hole space is formed below the hole of the outer tube 62 by the restricting portion 62b and the upper end of the cap 63. Is formed. The bar 61 is provided with a regulating member 61c at the lower end, and the regulating member 61c is screwed to the lower end of the bar 61 from below. The restricting member 61c is accommodated in the hole space and can move in the hole space. On the other hand, when the rod 8 is pulled upward, the restriction member 62b restricts the movement.

Hereinafter, the penetration rod of this invention and the penetration test method by the penetration testing machine 1 using the same will be described. In this penetration testing machine 1, the penetration test is started from a position where the screw point 7 at the tip of the penetration rod 4 is in contact with the ground surface. At this position, the manual operation button provided in the control unit 50 is pushed to reversely drive the lifting motor 41 to lower the lifting platform 3. When a start signal is given by pressing a start signal from this position, the control unit 50 automatically starts penetrating the penetrating rod 4 into the ground. That is, the control unit 50 receives the test start signal and reversely drives the lifting motor 41 and rotates the chuck motor 11. Thereby, the load by the mass of the lifting platform 3 etc. is loaded on the penetration rod 4, and it penetrates into the ground, rotating the penetration rod 4.

  During the test, the control unit 50 controls the brake means 42 to increase the load applied to the penetrating rod 4 from the minimum load 50N to 150N, 250N, 500N, 750N, and 1000N. Then, the rotational load torque applied to the penetrating rod 4 under each load, the half-rotation number of the penetrating rod 4, the penetrating amount, and the rotation speed increment are obtained and stored. This is performed for each unit section, with a section where the penetration rod 4 penetrates 25 cm as a unit section. Here, the rotational load torque acting on the penetrating rod 4 is obtained from the torque sensor 30.

  The torque sensor 30 is composed of the beams 31 and 32 and the strain gauges 33, 34, 35, and 36 as described above, and a total of four strain gauges use the strain corresponding to the twist of the beam as an electrical signal. Configured to detect. Specifically, when the chuck motor 11 rotates, the sun gear 21 attached to the output shaft 11a rotates. When the sun gear 21 is rotated, the planetary gears 22, 23, 24 meshed with the sun gear 21 are also rotated. These planetary gears 22, 23, 24 are internal teeth of the internal gear 25 fixed to the beams 31, 32. And is guided. Since the rotational reaction force of these planetary gears 22, 23, 24 is received by the internal gear 25, the rotational force of the planetary gears 22, 23, 24 is transmitted to the second output shaft 26 and via the annular chain 18. And transmitted to the penetrating rod 4. At this time, the rotational reaction force of the penetrating rod 4 is transmitted to the internal gear 25 via the annular chain 18 and the second output shaft 26 and is received by the internal gear 25. Since the internal gear 25 is fixed to the beams 31 and 32, the rotational reaction force of the penetrating rod 4 received by the internal gear 25 is transmitted to the beams 31 and 32 as a bending moment. Then, the beams 31 and 32 are distorted, and the strain gauges 33 and 34 and the strain gauges 35 and 36 detect the distortions as electrical signals and transmit them to the control unit 50.

  Further, the increment of the penetration amount of the penetration rod 4 is calculated by calculating the number of rotations of the sprocket 44 from the signal of the rotary encoder 45 that detects the rotation of the sprocket 44 and multiplying this by the penetration amount per revolution of the sprocket 44. can do. In addition, the control unit 50 calculates and stores the penetration depth of the screw point 7 by integrating the increments of the penetration amount, and calculates the penetration speed of the screw point 7 from the penetration amount per unit time. The control unit 50 repeats the above process and penetrates the screw point 7 to a predetermined depth.

  In order to calculate the rotational load torque Ts of the screw point 7 at each depth in the ground, as shown in FIG. 5A, first, the penetration rod 4 is rotated in a state where a predetermined load is applied to the penetration rod 4. Let At this time, as shown in FIG. 6A, since the protrusion 62a of the outer tube 62 is inserted into the groove 61b of the bar 61 from below, the connecting tool 60 and the screw point are accompanied by the rotation of the rod 8. 7 rotates integrally. When the torque sensor 30 detects the distortion at this time, the rotational load torque Tr + s of the penetrating rod 4, that is, the load torque obtained by adding the rotational load torque Tr applied to the rod 8 and the rotational load torque Ts applied to the screw point 7. Tr + s is obtained. The outer diameter of the connector 60 is smaller than the outer diameter of the screw point 7 and the surface area is sufficiently smaller than the rod 8. Therefore, the rotational load torque applied to the connector 60 is sufficiently smaller than the rotational load torque applied to the rod 8 or the screw point 7, and is ignored because it does not have a significant influence on the test result.

  Subsequently, in order to measure the rotational load torque Tr applied to the rod 8, as shown in FIG. 5 (b), the elevator 3 is raised at a predetermined height from the state shown in FIG. 5 (a). This rising amount is larger than the length of the long groove 4a of the rod 8 and is such that the protrusion 62a of the outer tube 62 inserted into the groove of the bar 61 is engaged with the groove 61b. When the elevator 3 is raised in this way, the rigid sphere 13 fitted below the long groove 4a of the rod 8 reaches the upper portion of the long groove 4a along the long groove 4a as the elevator 3 is raised. When the ascent is continued, the rod 8 and the bar 61 of the connector 60 are also raised by fitting over the long groove 4a. Then, as shown in FIG. 6 (b), the protrusion 62a of the outer tube 62 inserted into and engaged with the groove 61b of the bar 61 is disengaged from the groove 61b, and the bar 61 of the connector 60 and the outer The engagement with the tube 62 in the rotational direction is released. When the rod 8 is rotated in this state, the outer tube 62 and the screw point 7 of the connector 60 are not rotated, and only the rod 8 and the bar 61 are rotated. When the torque sensor 30 detects the distortion at this time, the rotational load torque Tr applied to the rod 8 is obtained.

  The rotational load torque Ts of the screw point 7 can be calculated by subtracting the rotational load torque Tr of the rod 8 from the rotational load torque Tr + s of the penetrating rod 4. The energy at the time of penetration by each load W applied to the screw point 7 and the rotational load torque Ts can be expressed as δE = πTsδn + Wδs. Here, δn is the half rotation number under each load (increment of half rotation number), and δs is the increment of penetration amount under each load. Further, πTsδn on the right side is the penetration energy due to rotation addition, and Wδs is the penetration energy due to load. That is, energy δE is expressed as the sum of penetration energy under load and penetration energy due to rotation. And the hardness etc. in each underground layer are determined by performing these tests at each underground depth.

  When the test at a predetermined depth in the ground is completed, it is necessary to raise the elevator and pull out the penetrating rod 4. In this case, when the lifting platform 3 is further raised from the state shown in FIG. 5B, the above-described restriction member 61c and the regulation portion 62b engage with each other in the raising direction to raise the lifting platform 3. As the rod 8 that rises along with the bar 61 of the coupler 60 rises, the outer tube 62 and the rod 8 of the coupler 60 also rise, so that the screw point 7 can be pulled out.

Thus, according to the penetrating rod of the present invention, and the penetrating test machine and penetrating test method using the penetrating rod, only the rotational load torque Ts applied to the screw point 7 can be accurately detected. Can be determined more accurately. Moreover, since the sum of the penetration energy by rotation addition calculated based on this detection data and the penetration energy by load can be calculated, by analyzing the sum of these energies, for example, clay with different moisture content It is possible to determine strata that were difficult to determine by conventional test methods, such as the Huge, alluvial, and humus soil layers.

It is a front view of the penetration testing machine concerning the present invention. It is an expanded sectional view of the chuck | zipper part of the penetration testing machine which concerns on this invention. It is an AA principal part expanded sectional view of FIG. It is a BB line principal part expanded sectional view of FIG. It is operation | movement explanatory drawing of the penetration rod of this invention, (a) is a state with which the rod and the screw point are connected, (b) is a figure which shows the state with which the connection is cancelled | released. FIG. 5A is an enlarged sectional view taken along line CC in FIG. 5A, and FIG. 5B is an enlarged sectional view taken along line DD in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Penetration testing machine 2 Prop 3 Lifting platform 4 Penetration rod 4a Long groove
5 Leg 6 Chain member 7 Screw point 8 Rod

DESCRIPTION OF SYMBOLS 10 Chuck 11 Chuck motor 11a Output shaft 12 Hollow sleeve 12a Hollow hole 13 Hard ball 14 Sprocket 15 Spring 16 Slide sleeve 17 Sprocket 18 Annular chain 19 Flange

20 planetary gear mechanism 21 sun gear 22 planetary gear 23 planetary gear 24 planetary gear 25 internal gear 26 second output shaft 27 carrier 28 carrier 29 carrier 30 torque sensor 31 beam 32 beam 33 strain gauge 34 strain gauge 35 strain gauge 36 strain gauge

40 Lifting unit 41 Lifting motor 42 Brake means 43 One-way clutch 44 Sprocket 45 Rotary encoder

50 Control unit

60 connector 61 bar 61a impact part 61b groove 61c regulating member 62 outer tube 62a projecting part 62b regulating part 63 cap

Claims (4)

In a penetrating rod consisting of a rod and a screw point attached to the tip of the rod, and penetrating the screw point into the ground during a penetration test,
  And a connecting tool for connecting the rod and the screw point. The connecting tool has a double pipe structure including an outer pipe to which the screw point is connected and a bar to which the rod is connected. The pipe and bar are usually engaged and rotated integrally in the circumferential direction, but when the rod is pulled up and moved in the axial direction, the circumferential engagement is released and only the rod rotates. A penetrating rod characterized in that it is configured to do. A rod and a screw point attached to the tip of the rod, and a penetrating rod that pierces the screw point into the ground and penetrates into the ground,
  A lifting platform that can be moved up and down along the column;
  A lifting unit for lifting and lowering the lifting platform;
  A chuck attached to the lifting platform and rotatably holding the penetrating rod;
  A chuck motor for applying rotational driving to the penetrating rod;
  A torque sensor for detecting a rotational load of the penetrating rod;
  The outer tube to which the screw point is connected and the bar to which the rod is connected form a double tube structure, and these outer tube and bar are usually engaged in the circumferential direction and rotated together. On the other hand, when the rod is lifted and the rod is moved in the axial direction, the coupling member configured to disengage the circumferential direction and rotate only the rod;
When the rod and screw point are connected, the rotational load of the rod and screw point is measured, while when the rod and screw point is disconnected, the rotational load of the rod is measured and the rod and screw point is measured. A control unit that calculates the rotational load of the screw point by subtracting the rotational load of the rod from the rotational load of
A penetration testing machine characterized by comprising: In the penetration test that measures the rotational load of the screw point by penetrating the penetration rod consisting of the rod and the screw point attached to its tip into the ground and rotating it,
Measure the rotational load of the rod and screw point and the rotational load of the rod only, and calculate the rotational load of the screw point by subtracting the rotational load of the rod only from the rotational load of the rod and screw point Penetration test method.   When measuring the rotational load of the rod and screw point, these rods and screw point are integrated, while when measuring the rotational load of only the rod, only the rod is rotated without rotating the screw point. The penetration test method according to claim 3.

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