JP2015055125A - Penetration testing method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a penetration testing method and a device therefor, capable of estimating the strength and properties of, in particular, the inside of a self-settling layer, and a transition section from a non-self-settling layer to a self-settling layer in details and with high reliability, by a simple structure in which a hanging scale is interposed between a loading device and a support device.SOLUTION: Test equipment used for a penetration testing method includes: a rod 1 having a screw point 2 at its tip; a loading device 3 applying a load to the rod 1 via a chuck device 5; a support device 10 for lifting the loading device 3 in a state that the loading device is hung and supported; and a hanging scale 30 interposed between the loading device 3 and the support device 10. Even in a self-settling layer where the rod 1 subsides by a load of the loading device 3, the load of the loading device 3 is set to be constant in principle, and a reaction of a ground is obtained on the basis of the load of loading device 3 and the a numeric value of the hanging scale 30. Then, a strength of the ground at each depth is estimated on the basis of the reaction of the ground and a settlement of the rod 1.

Description

  The present invention relates to a penetration test method and a penetration test apparatus used for a penetration test for ground investigation.

There is a Swedish sounding test method as a penetration test method for ground investigation.
The test equipment, instruments, and test methods according to JIS A1221 are as follows.

[Test equipment and instruments]
The test equipment and instruments are as follows.
The Swedish sounding test equipment consists of a screw point, a rod, and a loading / rotation / drawing device. When the load is loaded on the screw point via the rod, the relationship between the load and the penetration amount, and the rod after the penetration stop with a load of 1000 N The relationship between the number of rotations and the amount of penetration when rotating is required.

〔Test method〕
The test method is as follows.
a) Before the test, check that the screw point, loading device and rotating device are not damaged and that there is no deformation and damage of the rod and screw part. The screw point to be used should not be worn with a maximum diameter of 3 mm or more. When using an automatic recording device, a function check is performed before the test.

b) Attach the screw point to the tip of the screw point connecting rod, fix the loading clamp to the rod, attach the handle, and support it upright on the survey point.
If there is a possibility that the loading device may sink into the ground during penetration, a bottom plate or the like is installed in advance to prevent penetration.

c) First, load 100N on the clamp. Depending on the purpose of the test, a 500 N load may be initially loaded.

d) Check whether the rod penetrates into the ground with the load, and if so, measure the amount of penetration when the penetration stops without forcibly stopping, and use it as the penetration amount of the load. Also, observe the penetration situation at this time.

e) Increase load gradually and repeat d). The load stage is 50N, 150N, 250N, 500N, 750N and 1000N. Depending on the purpose of the test, the loading stage may be 500N, 750N and 1000N.

f) When the lower end of the loading device reaches near the ground surface, remove the load, remove the handle, add the rod while checking the verticality, pull up and fix the loading clamp, attach the handle, c) ~ Perform step e).

g) When the penetration of the rod stops at 1000 N, measure the amount of penetration, then rotate the rod clockwise so that no force is applied in the vertical direction, and half the rotation required to penetrate to the next scale line Measure the number. At that time, the rotation speed is set to about 60 half rotations or less per minute. In addition, the subsequent measurement is performed every 0.25 m (scale line).

h) If the penetration speed suddenly increases during the rotation penetration, stop the rotation and see if it penetrates only with a load of 1000N. Perform the following operations according to d) when penetrating or according to g) when not penetrating.

i) During measurement, if penetration suddenly occurs during the work of e) or sudden penetration occurs without applying rotation during the work of h), the weight is lowered immediately until the penetration stops. Record the work contents of, and start from work of e).

j) If the following conditions are confirmed, consider the end of measurement.
1) When the screw point reaches a hard layer and the number of half rotations per penetration of 0.05 m is 50 or more
2) When the resistance during rod rotation increases significantly
3) If it is impossible to penetrate due to an underground obstacle, record the measurement end reason and end depth in the record.

k) After completion of the test, remove the loading device, pull out the rod with the pulling device, check the number of rods, and check for any abnormalities in the screw points.

  Various applications have been filed for penetration tests or test equipment using the Swedish sounding test method.

  For example, Patent Document 1 discloses a load raising / lowering unit that suspends a weight to be placed on a loading platform and places the weight on the loading platform at the time of a test for the purpose of mechanizing the Swedish sounding test apparatus and reducing manual work. And a sounding test apparatus provided with a rotation transmission mechanism for mechanically rotating the rod during non-sedimentation.

  Patent Document 2 also includes a lifting platform that can be moved up and down along a standing column and a penetrating rod that is held by a chuck provided on the lifting platform and penetrates into the ground as the lifting platform is lowered. The penetration test apparatus is provided with a load sensor for detecting a load applied to the penetration rod.

  The penetration test apparatus is configured to raise and lower the lifting platform, and to apply a lifting force corresponding to the torque command value to the lifting platform and load the penetration rod as a test load with a load obtained by subtracting the lifting force from the total weight of the lifting platform. A load applied to the penetrating rod with a lifting motor and a control unit that feedback controls the torque command value output to the lifting motor based on the deviation between the value detected by the load detection sensor and the target test load value. As a load detection sensor for detecting, a structure in which a washer-type load sensor is attached to a chuck portion that holds a rod is shown.

Japanese Patent No. 36407779 JP 2013-029013 A

  In addition to the invention described in Patent Document 1, various things have been developed to save human power, improve work efficiency, and correct rod rotation work, etc., but are based on the Swedish sounding test, Since the load on the non-self-settling layer (rotating layer) that rotates the rod is a stepwise load setting such as 50N, 150N, 250N, 500N, 750N and 1000N, it is only possible to roughly grasp the reaction force or properties of the ground. .

  In addition, when a self-settled layer near the ground surface enters a non-self-settled layer (rotating layer), it is penetrated at the screw point at the tip by the rotation of the rod, and when it enters the self-sinking layer below it again, a load of 1000 N is applied. Since it is loaded, there is a problem that rapid settlement occurs and accuracy of measurement is impaired.

  In the invention described in Patent Document 2, the load applied to the penetrating rod is detected by the load detection sensor of the chuck portion, and the load applied to the penetrating rod is controlled by feedback control or feedforward control. However, the control is complicated. Therefore, it is difficult to check for errors and malfunctions.

  The present invention is a simple method that incorporates a suspension scale into the penetration test method that loads the load of the loading device onto the penetration rod, and details the strength and properties of the ground, particularly in the self-settled layer and in the transition zone from the non-settled layer to the self-settled layer. It is another object of the present invention to provide a penetration test method and apparatus that can be estimated with high reliability.

  The penetration test method of the present invention includes a rod for penetrating the ground, a loading device for applying a downward load to the rod, and a lifting balance for measuring a vertical force applied to the loading device by hanging the loading device. And the reaction force of the ground is obtained based on the load of the loading device described above when the rod penetrates the ground and the numerical value of the suspension scale.

  Further, an invention form in which the above principle is developed as a penetrating test method similar to the Swedish sounding test includes a rod having a screw point at a tip thereof, a chuck device for detachably gripping the rod, and a chuck device. In a non-self-settling layer in which the rod does not sink only by the load of the loading device, a penetration test device comprising a loading device for applying a load to the rod and a rotating device for rotating the rod about an axis is used. Is a penetration test method for estimating the strength of the ground from the relationship between the amount of rotation and the amount of penetration of the rod, and a driving mechanism for lifting and lowering the loading device in a state where the loading device is suspended and supported on the penetration test device. And a suspension scale interposed between the loading device and the support device, and measuring a vertical force applied to the loading device. In the self-sink layer where the rod sinks due to the load of the loading device described above, the ground reaction force is obtained based on the load of the loading device described above and the value of the suspension scale, and based on the ground reaction force and the amount of settlement of the rod. It is characterized by estimating the strength of the ground at each depth.

  The penetration test device described above is an application of the penetration test device used in the Swedish sounding test method. However, a self-settled layer is formed by interposing a suspension scale between the loading device and the support device for supporting the suspension. The reaction force of the ground is obtained indirectly from the numerical value of the suspension scale.

  In the conventional penetration test device, the strength of the ground in the self-sink layer could not be measured in detail, but according to the present invention, a simple mechanism in which a suspended scale is interposed between the loading device and the support device, In the self-sedimentation layer, the ground reaction force can be obtained indirectly in real time from the measurement value of the suspension scale, so that the strength of the self-sedimentation layer can be accurately estimated for each depth.

  In the case of the Swedish sounding test method, as described above, in the self-sink layer, the load is changed stepwise from 50N, 150N, 250N, 500N, 750N and 1000N, or 500N, 750N and 1000N depending on the purpose of the test. In the present invention, depending on the ground conditions and the purpose of the test, the load of the loading device may be changed in stages, but in principle, a constant load, for example, without distinguishing between the non-sedimentation layer and the self-sedimentation layer, Test at 1000N.

  The suspension scale is not particularly limited as long as it has a predetermined performance capable of measuring the load of the loading device or more. For example, a commercially available suspension scale called a crane scale can be used.

  FIG. 1 shows the principle of the penetration test method of the present invention. The load of the weight including the loading device 3 on the rod 1 having the screw point 2 at the tip is assumed to be 1000N.

  In the self-sink layer, 1000N, which is a weight load (load of the loading device 3), acts on the rod 1 downward, and at this time, an upward reaction force R (<1000N) acts on the tip of the rod 1 from the ground.

  The display X of the hanging balance 30 becomes 1000 = R, and the ground reaction force R = 1000−X can be obtained. By loading the chain 12 as the suspension material by the driving device of the supporting device 10 that supports the loading device 3 through the suspension scale 30, the loading device 3 is lowered, and the reaction force R and the settlement at that time are lowered. By recording the amount (penetration amount), the strength of the ground at each depth and its change can be estimated.

  On the other hand, in the non-self-settling layer, the reaction force R from the ground balances with the weight of the weight applied to the rod 1 (the load of the loading device 3) of 1000 N, so that no settlement occurs, and the display X = 0 on the suspension balance 30 It becomes. In the non-sedimentation layer, the rod 1 is rotated from this state, and the ground strength can be estimated by the estimation method in the Swedish sounding test method from the relationship between the rotation amount and the rod penetration amount.

  In the penetration test method of the present invention, regarding the problem of sudden change of the penetration amount when the tip of the rod 1 enters the self-sink layer again from the non-self-sink layer, the load of the loading device 3 is temporarily applied to the support device 10. It can be dealt with by making it bear. At this time, the suspension member such as the chain 12 changes from a slack state to a tension state. By feeding the chain 12 from this state, the loading device 3 descends as described above, and by recording the reaction force R and the amount of subsidence at that time, the strength of the ground at each depth and its change. Can be estimated.

  A penetration test apparatus according to the present invention is an apparatus for use in the above-described penetration test method, a rod having a screw point at a tip thereof, a chuck device that detachably holds the rod, and the chuck device through the chuck device. A penetration testing device comprising a loading device for applying a load to a rod and a rotating device for rotating the rod about an axis, wherein all or a part of the load applied by the loading device described above is determined by the weight of the loading device itself and the weight A structure provided by the weight of the chuck device, and a support device provided with a drive mechanism for raising and lowering the load device in a supported state, and the vertical between the load device and the support device. It is characterized by comprising a suspension scale for measuring the directional force.

  If a part of the load applied by the loading device is given by one or a plurality of weights that can be loaded on the loading device, the load on the loading device main body can be suppressed and the movement and the like can be facilitated.

  According to the penetration test method of the present invention, the reaction force of the ground can be obtained in real time based on the numerical value given by the suspension scale.

  The device used in the present invention has a simple structure in which a suspended scale is interposed between a loading device and a support device having a driving mechanism, and particularly in a self-settling layer or a transition zone from a non-settling layer to a self-settling layer. The strength and properties of the ground can be estimated in detail and with high reliability.

  Moreover, in the conventional Swedish sounding test, the load in the self-sink layer is limited to 50N, 150N, 250N, 500N, 750N and 1000N, whereas in the present invention, the load by the loading device is one type. Can do.

  By making the load constant even in the self-sinking layer, it is not necessary to load and unload weights that are performed in a general Swedish sounding test during the test.

It is the figure which showed the principle of the penetration test method of this invention. It is a perspective view which shows one Embodiment of the penetration test apparatus used for the penetration test method of this invention. It is the elevation which simplified and showed only the basic composition of the penetration test device. It is the perspective view which simplified and showed the relationship between a rod, a loading apparatus, and a weight.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
In this embodiment, the total weight of the loading device 3 and the devices associated with the loading device 3 such as the chuck device 4 is 500 N, and a weight (additional weight) 6 of 250 N is added to the loading device 3 as shown in FIG. By placing the unit, a load of up to 1000 N, which is the same as the Swedish sounding test method, can be applied.

  The combination of the weights of the weights 6 placed on the apparatus is arbitrary, and it can be configured so that the loading apparatus 3 and its associated apparatus alone are 1000 N, but in this embodiment, the loading apparatus 3 can be easily moved. Considering that the weight 6 can be placed by human power, the above distribution is adopted.

  2 and 3 show the basic configuration of the penetration test apparatus according to the present embodiment. The guide rail 8 (shown by a broken line in FIG. 3) formed on an L-shaped mount 7 made of steel is provided on the back side. A loading device 3 provided with a sliding portion 4 composed of a roller or the like can be moved up and down.

  Two weights 6 can be placed on the loading device 3 as described above, and the weight of one weight 6 in this embodiment is 250 N, which can be easily loaded and unloaded manually.

  A chuck device 5 is installed on the top of the loading device 3, and the shaft of the rod 1 having the screw point 2 at the tip used in the Swedish sounding test can be detachably held.

  The rotation of the rod 1 in the non-self-settling layer is performed by rotating the chuck device 5 with a rotation motor 21 (indicated by a broken line in FIG. 3) installed inside the loading device 3.

  A support device 10 having a drive motor 11 is provided on the top of the gantry 7, and the chain 12 is wound and unwound by the rotation of the drive motor 11, and the loading device 3 is moved up and down. .

  When the device is lifted after the penetration test is completed, the loading device 3 is lifted along the guide rail 8 of the gantry 7 by winding the chain 12 by the rotation of the drive motor 11.

  In the present invention, a suspension balance 30 is interposed between the support device 10 and the loading device 3, and the suspension balance 30 includes the total force applied to the loading device 3 (including the weight of the loading device 3 and the weight 6). The power of is displayed.

  In the penetration test, first, the loading device 3 is moved to the test position by using the wheels 9 of the gantry 7 which also serves as a carriage, and two 250 N weights 6 are placed on the loading device 3 so that a total of 1000 N is obtained. Construct a weight.

  The loading device 3 at this time is supported by a support device 10 including a chain 12 that is unwound and wound up by a drive motor 11 on a gantry 7, and a suspension scale 30 is attached to the lower end portion of the chain 12. The loading device 3 main body is supported via the suspension scale 30.

  If the rod 1 with the screw point 2 attached to the tip is gripped by the chuck device 5 provided in the loading device 3, a load of 1000 N is applied to the rod 2 downward, while the resistance force R from the ground is applied to the tip of the rod. Will act. At this time, the suspension scale 30 displays a value obtained by subtracting the resistance R of the ground from 1000N.

(A) Measurement in the self-settled layer In the case of the Swedish sounding test method, 50N, 150N, 250N, 500N, 750N, and 1000N are loaded sequentially. However, in the present invention, it is not necessary to change the loaded load in principle. In this embodiment, the load is set to 1000 N for both the self-settling layer and the non-sedimenting layer.

  In the self-sink layer, as described above, the load 1000N of the loading device 3 acts downward on the rod 1, and at this time, the reaction force R (<1000N) upward from the ground acts on the tip of the rod 1, 30 display X = 1000-R, and the ground reaction force R = 1000-X can be obtained.

  The amount of subsidence (penetration amount) at this time is recorded by the encoder 13 with the amount of unwinding of the wire 14 attached to the loading device 3, and the strength of the ground at each depth and its change are estimated from the reaction force R and the amount of subsidence. can do.

(B) Measurement in non-self-settling layer (rotating layer) In the non-self-settling layer that does not sink at 1000 N which is the maximum load in this embodiment, the rod 2 is rotated clockwise (rotational speed) as in the Swedish sounding test method. Is about 60 half revolutions per minute or less), and measures the half revolution required to penetrate to the next scale line (25 cm). In this embodiment, this rotation is performed by driving the rotation motor 11 provided in the loading device 3 and rotating the chuck device 5 via the transmission mechanism.

  Depending on the purpose of the test, the amount of rotation and the amount of settlement may be determined by a standard and test method different from the Swedish sounding test method.

(C) Others When a self-settling layer comes under the non-self-settling layer, the chain 12 that has been loosened due to the resistance from the ground in the non-self-settling layer is tensioned, and the load of the loading device 3 is temporarily Will bear. After that, in the self-sinking layer, the chain 12 is unwound and the loading device 3 is lowered at a constant speed (not necessarily a constant speed) while measuring in the self-sinking layer described in (A). Accordingly, the measurement in the self-settling layer (A) and the measurement in the non-sedimentation layer (B) are performed to a predetermined depth while adding the rod 1.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. For example, in the embodiment, the weight of the entire weight including the weight of the loading device 3 is set to 1000 N, but the weight of the weight can be arbitrarily set.

DESCRIPTION OF SYMBOLS 1 ... Rod, 2 ... Screw point, 3 ... Loading apparatus, 4 ... Sliding part, 5 ... Chuck apparatus, 6 ... Weight (additional weight), 7 ... Mount, 8 ... Guide rail, 9 ... Wheel,
DESCRIPTION OF SYMBOLS 10 ... Support apparatus, 11 ... Drive motor (lifting / lowering of a loading apparatus), 12 ... Chain, 13 ... Encoder, 14 ... Wire,
21 ... Rotary motor (rotation of the rod),
30 ... hanging scale

In the penetration test method of the present invention, the ground reaction force (R) when a rod loaded with a downward load penetrates the ground is continuously obtained in the depth direction, so that the strength of the ground at each depth is obtained. An intrusion test method for estimating a rod for penetrating into the ground, a loading device for applying a downward load to the rod, and a suspension for measuring a vertical force applied to the loading device by hanging the loading device described above Using a scale, the reaction force (R) of the ground when the rod penetrates the ground at each depth is expressed as the difference between the load (W) of the loading device and the measured value (X) of the suspension scale (W− R), and the strength of the ground is estimated .

Further, an invention form in which the above principle is developed as a penetrating test method similar to the Swedish sounding test includes a rod having a screw point at a tip thereof, a chuck device for detachably gripping the rod, and a chuck device. In a non-self-settling layer in which the rod does not sink only by the load of the loading device, a penetration test device comprising a loading device for applying a load to the rod and a rotating device for rotating the rod about an axis is used. Is a penetration test method for estimating the strength of the ground from the relationship between the amount of rotation and the amount of penetration of the rod, and a driving mechanism for lifting and lowering the loading device in a state where the loading device is suspended and supported on the penetration test device. And a suspension scale interposed between the loading device and the support device, and measuring a vertical force applied to the loading device. In scuttled layer the rod by the load of the loading device is sinking, calculated as the difference (W-R) of the measured value of the suspension balance the load (W) of the reaction force of the ground the (R) said loading device (X) The strength of the ground at each depth is estimated based on the reaction force (R) of the ground and the amount of settlement of the rod.

Claims (5)

  A rod for penetrating into the ground, a loading device for applying a downward load to the rod, and a lifting balance for measuring a vertical force applied to the loading device by suspending the loading device described above, wherein the rod is ground A penetration test method characterized in that the reaction force of the ground is obtained based on the load of the loading device described above when penetrating into the ground and the numerical value of the suspension scale. A rod having a screw point at the tip; a chuck device for detachably holding the rod; a loading device for applying a load to the rod via the chuck device; and a rotating device for rotating the rod about an axis; In a non-self-settling layer where the rod does not sink only by the load of the loading device, the rod is rotated and the penetration test is performed to estimate the strength of the ground from the relationship between the rotation amount and the rod penetration amount. A method,
A support device provided with a drive mechanism for raising and lowering the loading device in a state where the loading device is suspended and supported in the penetration test device, and interposed between the loading device and the supporting device, in the vertical direction applied to the loading device. A suspension scale for measuring force,
In the self-sink layer where the rod sinks due to the load of the loading device described above, the ground reaction force is obtained based on the load of the loading device described above and the value of the suspension scale, and based on the ground reaction force and the amount of settlement of the rod. A penetration test method characterized by estimating the strength of the ground at each depth.   The penetration test method according to claim 1 or 2, wherein the load of the loading device is constant, and the reaction force of the ground is obtained as a difference between the load of the loading device and a measured value of the suspension scale. . A rod having a screw point at a tip; a chuck device that detachably holds the rod; a loading device that applies a load to the rod via the chuck device; and a rotating device that rotates the rod about an axis. A penetration test device provided,
A structure in which all or part of the load applied by the loading device is given by the weight of the loading device itself and the weight of the chuck device,
A support device having a drive mechanism for moving up and down while supporting the loading device;
An intrusion test apparatus comprising: a lifting balance that is interposed between the loading device and the support device and measures a vertical force applied to the loading device.   5. The penetration test apparatus according to claim 4, wherein a part of the load applied by the loading device is given by one or a plurality of weights that can be loaded on the loading device.

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