JP2015229895A - Testing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide testing equipment that uses a falling weight that efficiently prevents re-striking of a test object by the weight.SOLUTION: Test equipment is used in a test that causes a weight to fall and strike a test object, and includes a halting device connected to the weight and a rod member inserted into the halting device in a way that allows relative movement in the vertical direction with the halting device. The halting device is configured so as to generate a frictional force between the device and the rod member in the course of the relative movement. The frictional force generated when the halting device falls relative to the rod member is set to be greater than the frictional force generated when the halting device rises relative to the rod member, and also to be sufficient to stop falling of the weight.

Description

  The present invention relates to a test apparatus that uses falling of a weight.

  In civil engineering and construction work, piles may be laid to strengthen the ground support. In order to obtain data on pile bearing capacity and land subsidence, vertical loading tests are being conducted on the piles that have been laid. For example, a pile head is struck by a free fall from a predetermined height, and the relationship between the load and subsidence generated at that time is measured and analyzed to estimate or confirm the bearing capacity of the pile. Loading test may be performed.

  One type of dynamic loading test is a rapid loading test (stanamic test). In this rapid loading test, a shock wave caused by the impact of the pile head is propagated from the pile head to the tip of the pile, and a loading continuation time more than five times as long as it takes to return to the pile head is given. For this reason, a cushioning material (cushion) such as rubber or spring is installed on the pile head and hit from above. By such a method, the influence by the propagation of elastic waves is eliminated, and a highly reliable test result close to a static loading test can be obtained (see Patent Document 1).

  In the rapid loading test, rapid load and pile head displacement are obtained as data. At this time, there was a problem that accurate data could not be obtained as the displacement amount of the pile head because the free-falling weight repeatedly rebounded and hit the pile head again. As a countermeasure against this problem, a loading test apparatus intended to prevent re-blow by a weight by providing a stopping means for stopping a weight that has rebounded after hitting a pile head has been proposed (see Patent Document 2). ).

Japanese Patent No. 5443911 JP 2009-249858 A

  Patent Document 2 describes an example of a stopping unit that includes a hydraulic actuator. In such a configuration, a relatively powerful hydraulic system that can stop the weight in the air is required, and a relatively high precision hydraulic pressure is required to stop the weight before the weight starts to fall again. Operation timing control is required, and the control becomes complicated, and the control timing needs to be adjusted, which is complicated. Also, it is necessary to keep the hydraulic pressure working in order to maintain the weight stopped state. As described above, the apparatus described in Patent Document 2 is complicated and complicated in configuration and control for preventing re-striking by the weight, and cannot be said to be efficient.

  Therefore, an object of the present invention is to provide a test apparatus that can efficiently prevent the weight from re-striking the test object in the test apparatus that uses the falling of the weight.

  A test apparatus according to one aspect of the present invention is a test apparatus used for a test performed by dropping a weight and hitting a test object, and a stop device connected to the weight, and a relative to the stop device in the vertical direction. A rod member that is inserted into the stop device so as to be movable, and the stop device is configured to generate a frictional force with the rod member when moving relative to the rod member. On the other hand, the friction force when the stop device is lowered is larger than the friction force when the stop device is raised with respect to the rod member, and is set so as to stop the falling of the weight. is there.

  According to the test apparatus defined in the above aspect, the frictional force when the stop device is lowered with respect to the rod member is larger than the friction force when the stop device is raised with respect to the rod member, and the weight Since the weight is set so that it can be stopped, when the weight rebounds upward after hitting the test object (for example, pile head), the weight is allowed to rise while preventing the weight from falling again. Can do. Thereby, even if it does not depend on complicated control, the repetition of the unnecessary hit | damage by a weight can be prevented automatically.

  According to another aspect of the present invention, the stop device includes a stop member that can generate a frictional force with the rod member, and a locking member that can be locked to the stop member. When the stop member is locked by the locking member, the stop member is not locked by the locking member, and the locking state is a state in which the stop member does not substantially generate a frictional force with the bar member. Thus, the stop member is configured to be able to realize a friction state in which a friction force can be generated between the stop member and the rod member. According to yet another configuration, the stop device is configured to change from the locked state to the frictional state due to falling of the weight. According to this, by automatically switching from the locked state to the frictional state due to the falling of the weight, it is possible to stop the weight without particularly adjusting the timing and prevent re-blow.

  According to still another aspect, the stop member of the test apparatus is provided with a hole through which the rod member is inserted, and the stop member is rotatable so as to change its inclination angle, and is in a frictional state. When the stop device descends relative to the rod member in step S2, the stop member is in a predetermined inclined state, so that the edge of the hole and the rod member are engaged with each other. On the other hand, when it raises relatively, a stop member will be in the state different from a predetermined inclination state.

According to still another aspect, the stop member includes a brake shoe and a pressing member that presses the brake shoe against the rod member, and the pressing member applies a pressing force to the brake shoe in the locked state. In the friction state, a pressing force can be applied to the brake shoe.
According to such a configuration, it is possible to prevent repeated rebounding of the weight and consequently re-blow of the test object by using a relatively simple device without using a complicated system such as a hydraulic system.

FIG. 1 is a perspective view showing a test apparatus according to the first embodiment of the present invention. FIG. 2 is a perspective view showing a main part of the test apparatus according to the first embodiment. FIG. 3 is a perspective view showing a main part of the test apparatus according to the first embodiment. FIG. 4 is a perspective view showing a main part of the test apparatus according to the first embodiment. FIG. 5 is a partial cross-sectional view showing a main part of the test apparatus according to the first embodiment. FIG. 6 is a front view showing a test apparatus according to the second embodiment of the present invention. FIG. 7 is a partial cross-sectional view showing a test apparatus according to the second embodiment. FIG. 8 is a view showing a locking member of the test apparatus according to the second embodiment. FIG. 9 is a cross-sectional view showing part of the bar member and the brake shoe of the test apparatus according to the second embodiment.

(First embodiment)
A test apparatus 1 according to a first embodiment of the present invention will be described with reference to FIG. Below, in order to measure the bearing capacity of a pile, the case where the test apparatus 1 is used for a rapid loading test is demonstrated as an example. As shown in FIG. 1A, the test apparatus 1 according to this embodiment includes a weight 10, a stop device 20, and a bar member 30 as main elements. The stop device 20 is fixed to the upper part of the weight 10. The bar member 30 is inserted through the weight 10 and the through hole of the stop device 20. A hook 50 is attached near the upper end of the bar member 30. A measuring device (not shown) is attached to a pile head of a test pile (not shown) by the test device 1. The lower end of the bar member 30 is installed or opposed to the upper surface of the measuring device. When the test apparatus 1 is used for a rapid loading test, the measuring apparatus is configured by a buffer member, a load cell, a strain gauge, and the like, but since it is a part belonging to the prior art, a detailed description is omitted.

  In the test apparatus 1 in the preparation state shown in FIG. 1A, the tip of the hook 50 is hung on the groove 11 provided in the upper part of the weight 10. When the hook 50 is removed from this state, the weight 10 falls along the bar member 30 as shown in FIG. 1 (B) and strikes the pile head of the pile that is the test object via the measuring device. The bearing capacity of the pile can be calculated by determining the relationship between the load received by the pile and the amount of settlement of the pile (displacement of the pile head) by a nonlinear damping method (corrected unloading point method) or the like. When the weight 10 that has jumped up starts to fall again after the impact, the stop device 20 immediately and automatically exhibits a stop function, and stops the weight 10 as shown in FIG. This prevents the pile head from being hit again by the weight 10.

  Next, functions and effects of the stopping device 20 according to the present embodiment will be described with reference to FIGS. FIG. 2 is a perspective view showing the state of the stopping device 20 in a state after the weight 10 starts to fall and before hitting the pile head. The stop device 20 includes a stop member 21 in which a plurality of plates 21 (first to third plates 21A, 21B, and 21C in this embodiment) are hinged to each other, and a part of the plate 21 is fixed to the weight 10. The locking member 22 is hingedly connected to the vicinity of both ends of 21. As shown in FIG. 2, the stop member 21 of the stop device 20 is folded at the start of the test, and the state is held by the locking member 22. When the weight 10 falls and strikes the pile head, as shown in FIG. 3, the locking member 22 rotates around the hinge by the inertial force, thereby canceling the state of locking the stop member 21 and stopping. The member 21 is released.

  The weight 10 jumps upward after hitting the pile head. Thereafter, the stop member 21 is released as shown in FIG. 4 until the weight 10 resumes dropping. The stop member 21 of the present embodiment is composed of three plates, and the lowermost first plate 21A is fixed to the weight 10, and a locking member 22 is hinged to both ends thereof. On the side, it is further hinge-connected to the end of the intermediate second plate 21B, and the other end of the second plate 21B and one end of the uppermost third plate 21C are hinge-connected. The first to third plates 21A, 21B, 21C are each provided with a hole, and the rod member 30 is inserted therethrough. When the stop member 21 is folded as shown in FIG. 2, the rod member 10 is loosely fitted into the hole of the third plate 21C. On the other hand, when the stop member 21 is released as shown in FIG. 4, the third plate 21 </ b> C is inclined by the action of the hinge connection, so that the edge of the hole of the third plate 21 </ b> C and the peripheral surface of the rod member 30 are finally obtained. Will be in mesh. The number of plates and the number of locking members 22 are arbitrary as long as the same function and effect can be exhibited.

  This state will be described with reference to a partial sectional view of FIG. That is, when the stop member 21 is released, the third plate 21C is inclined, and the edge of the hole is in contact with the rod member 30 (however, it may be in contact before that). When the weight 10 further falls in this state, the third plate 21C descends behind the weight 10 due to the fact that the edge of the hole of the third plate 21C and the rod member 30 are in contact. This further increases the inclination of the third plate 21C. Ultimately, the bar member 30 is sandwiched between the two edge portions A facing in the diameter direction of the hole. When the weight 10 is further lowered, a force is applied in a direction in which the third plate 21C is further inclined due to the hinge connection structure of the stop member 21, whereby both edge portions A are connected to the rod member 30. The pressing force increases so as to sandwich the. As a result, the relative movement of the third plate 21C and the rod member 30 in the axial direction (vertical direction in FIG. 5) is finally stopped, and thus the lowering of the weight 10 is stopped. This state is referred to as a meshing state. When the weight 10 is lifted by an external force, the inclining angle of the third plate 21C is loosened, and the meshing state is canceled. Each edge A may be a single point, may have a spread, or may be a plurality of points. According to such a configuration, the weight 10 that has bounced up after hitting can be automatically stopped at a suitable timing with a simple configuration, and re-blow of the test object by the weight 10 can be prevented by a simple method. Can do.

(Second Embodiment)
Next, a test apparatus 100 according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a front view of the test apparatus 100 of the second embodiment. The test apparatus 100 includes a weight connection member 110, a stop member 120, and a bar member 130. The weight connection member 110 is a substantially cylindrical member having a connection portion 111 for connecting to a weight (not shown) at the lower end. The bar member 130 includes a hanging portion 131 on the upper end side, and the lower end side thereof is inserted concentrically with the weight connection member 110. The stop member 120 includes a guide part 121, an upper arm 122, a lower arm 123, a brake shoe 124, a parallel maintaining member 125, a biasing member 126, and an engaging part 127. The guide part 121 includes a cylindrical part 121A that is loosely fitted to the outer periphery of the rod member 130, and a guide flange 121B that is erected on the outer peripheral surface of the cylindrical part. One end of the upper arm 122 is hinged to the guide flange 121 </ b> B, and the other end is hinged to the one end of the lower arm 123. The other end of the lower arm 123 is hinged to a flange on the outer peripheral surface of the weight connection member 110.

  The brake shoe 124 includes a brake pad 124A facing the outer peripheral surface of the rod member 130, and a brake flange 124B standing on the surface of the brake pad 124A opposite to the rod member 130. The brake flange 124 </ b> B is hinged to portions other than both ends of the upper arm 122 and is hinged to the guide flange 121 </ b> B via the parallel maintaining member 125. The parallel maintaining member 125 is two or more members that are spanned in parallel with each other by hinge connection on both the guide flange 121B and the flange 123B of the brake shoe 124. With such a configuration, the brake shoe 124 can perform an operation of approaching and separating from the outer peripheral surface of the bar member 130 while maintaining a parallel state between the brake pad 124 </ b> A and the outer peripheral surface of the bar member 130. The urging member 126 is, for example, a spring and is laid across the upper arm 122 and the lower arm 123 and urges so as to open an angle therebetween. FIG. 7 is a partial cross-sectional view showing the test apparatus 100 of FIG. 6 in a state where front portions of the guide part 121 and the weight connection member 110 are cut off.

  The weight connection member 110 includes a support arm 112 and a locking member 113 on the outer peripheral surface near the upper end thereof. As shown in FIG. 8A, the locking member 113 includes an integral hook 113 </ b> A and a biasing weight 113 </ b> B, and is hinged to the tip of the support arm 112. The hook 113 </ b> A can be engaged with an engagement portion 127 provided on the upper arm 122 of the stop member 120.

  Next, functions and effects of the test apparatus 100 will be described. In the state of FIG. 6, the weight connection member 110 and the stop member 120 connected to a weight (not shown) can move relative to the bar member 131 in the vertical direction. Prior to the start of the test, the relative movement is prevented by a stopper (not shown). When the stopper is released, the weight, the weight connecting member 110, and the stop member 120 are integrally dropped.

  FIG. 8A is a diagram showing the state of the locking member 113 after the weight starts to fall and before the weight strikes the pile head of the pile that is the test object. The hook 113 </ b> A is engaged with the engaging portion 127. Therefore, the relative positional relationship between the upper arm 122 and the lower arm 123 is fixed. When the weight falls and hits the pile head, as shown in FIG. 8 (B), the urging weight 113B rotates around the hinge by the inertial force, thereby rotating the hook 113A integrated with the urging weight 113B. It is moved and released from the engaging portion 127. Since the engagement state between the hook 113 </ b> A and the engagement portion 127 is canceled, the upper arm 122 and the lower arm 123 can be relatively rotated.

  Then, due to the action of the biasing member 126, the upper arm 122 and the lower arm 123 rotate relatively in the opening direction. Thus, the upper arm 122 presses the brake shoe 124 from the state shown in FIG. 9A toward the bar member 130 via the hinge connection. However, the pressing force by the urging member 126 is set to such a force that the brake pad 124A is at least in contact with the bar member 130 as shown in FIG. 9B. FIG. 9 is a partial cross-sectional view of the test apparatus 100 taken along the alternate long and short dash line IX in FIG.

  After hitting the pile head, the weight jumps upward. In this case, since the angle between the upper arm 122 and the lower arm 123 becomes smaller, the force with which the upper arm 122 presses the brake shoe 124 against the peripheral surface of the bar member 130 becomes smaller or disappears. When the weight starts to fall again, the weight acts to pull the weight connection member 110 downward and widen the angle between the upper arm 122 and the lower arm 123. As a result, the upper arm 122 presses the brake shoe 124 against the peripheral surface of the bar member 130 more strongly. In this way, a large frictional force is generated between the brake pad 124A and the peripheral surface of the rod member 130, and finally the weight can be stopped from dropping. In the present embodiment, two sets of stopping means 120 are installed at two places sandwiching the rod member 131, but the present invention is not limited to this, and three sets, four sets or more of stopping means 120 are used. Also good.

  As described above, the example in which the test apparatus according to the present invention is used for the rapid loading test of a structure, particularly a pile, has been described. However, the present invention is not limited thereto, and the test apparatus according to the present invention may be used for any impact test of the structure. For example, instead of hitting with a hammer to generate an elastic wave in a pile integrity test (Pile Integrity test: IT test) or a quality test of a concrete structure, the test apparatus of the present invention is used. It is also possible to hit by dropping the weight. In addition to the structure test, the test apparatus according to the present invention can be used for ground investigation (test performed by hitting the ground with a weight).

  The locking member is not limited to the configuration using only mechanical means as described above, but the impact of the test object by the weight is detected, and the engagement between the stopping member and the locking member is detected by an electric or magnetic method based on the detection result. It is good also as a structure which cancels a stop state.

  The present invention is not limited to the description of the embodiments of the invention. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

1, 100 Test device 20 Stop device 21, 120 Stop member 22, 113 Lock member 30, 130 Bar member

Claims (5)

A test apparatus used for a test performed by dropping a weight and hitting a test object,
A stop device connected to the weight;
A bar member inserted through the stop device so as to be relatively movable in the vertical direction with the stop device,
The stop device is configured to generate a frictional force with the bar member when moving relative to the bar member;
The frictional force when the stop device is lowered with respect to the rod member is larger than the friction force when the stop device is raised with respect to the rod member, and the falling of the weight is stopped. Test equipment set up as possible. The stop device includes a stop member that can generate a frictional force with the rod member, and a locking member that can be locked to the stop member,
The stop device includes a lock state in which the stop member is locked by the lock member, and the stop member is in a state in which substantially no frictional force is generated between the stop member and the stop member. 2. The structure according to claim 1, wherein the member is not locked by the locking member, and is configured to be able to realize a friction state in which the stop member can generate a frictional force with the rod member. Testing equipment.   The test apparatus according to claim 2, wherein the stop device is configured to change from the locked state to the friction state when the weight falls. The stop member is formed with a hole through which the bar member is inserted,
The stop member is pivotable to change its angle of inclination;
When the stop device descends relative to the bar member in the friction state, the stop member is in a predetermined inclined state, whereby the edge of the hole and the bar member are engaged with each other,
4. The test apparatus according to claim 2, wherein when the stop device is raised relative to the rod member in the friction state, the stop member is in a state different from the predetermined inclined state. 5. The stop member includes a brake shoe and a pressing member that presses the brake shoe against the bar member;
The pressing member is configured to apply no pressing force to the brake shoe in the locked state and to apply a pressing force to the brake shoe in the friction state. The test apparatus according to claim 2 or claim 3.

Images