CN209945977U

CN209945977U - Reaction frame for testing bonding strength of sprayed concrete and rock on site

Info

Publication number: CN209945977U
Application number: CN201920604456.7U
Authority: CN
Inventors: 卢长波; 徐敏; 徐文杰; 方赵君; 张利
Original assignee: Sinohydro Bureau 12 Co Ltd
Current assignee: Sinohydro Bureau 12 Co Ltd
Priority date: 2019-04-29
Filing date: 2019-04-29
Publication date: 2020-01-14
Anticipated expiration: 2029-04-29

Abstract

The utility model relates to a reaction frame for field test shotcrete and rock bonding strength, a plurality of screw rods including bottom plate, load board, connection bottom plate and load board and cup joint on the screw rod and lie in load board top and the last nut and the lower nut of below respectively. The utility model discloses a reaction frame for field test shotcrete and rock bonding strength through the angle of adjusting the upper bearing plate, reaches the coaxial function of jack and dowel steel atress to guaranteed that the atress of guaranteeing the bonding strength test does not take place the deviation. Moreover, the reaction frame can be disassembled into a plurality of parts, is convenient to carry and install, and reduces the labor intensity of field workers.

Description

Reaction frame for testing bonding strength of sprayed concrete and rock on site

Technical Field

The utility model belongs to the field of hydraulic and hydroelectric engineering construction, concretely relates to a reaction frame that is used for on-the-spot test shotcrete and rock bonding strength.

Background

The sprayed concrete is a common construction method for tunnel and cavern support, the detection of the bonding strength of the sprayed concrete is an important means for detecting the quality of the sprayed concrete, and the test methods for the bonding strength of the sprayed concrete are correspondingly specified in the technical Specifications for anchor and spray support in the hydraulic and hydroelectric engineering (SL377-2007), the technical Specifications for rock-soil anchor rods and sprayed concrete support engineering (GB50086-2015) and the construction Specifications for anchor and spray support in the hydroelectric engineering (DL/T5181 and 2017), wherein the bonding strength test methods in the specifications are approximately the same, and after conclusion, the main detection methods are three, namely 1, a test piece reserved drawing method, 2, a drill core drawing method and 3, a large plate spray indoor splitting method. The goals of the test are mainly two-fold: 1. the stress is basically consistent with the bonding stress of the concrete sprayed on site, and 2, the test viscosity meets the requirement. However, the three methods at present have defects in the test piece forming, the test piece stress, the base surface requirement, the test instrument and the test method with different degrees of formation.

1) In-situ core drilling and drawing method

In the on-site core drilling and drawing method, when a core is drilled, the swing of a drilling machine disturbs and damages a concrete test piece; the loading is difficult to ensure not to be eccentric when the pull rod is buried in a drilled hole or the pull head is stuck by epoxy resin; stress concentration is easily caused by insufficient thickness of a sprayed layer, and the axial tension bonding strength obtained by the on-site core drilling and drawing method is small due to the factors, so that the detection result of the method cannot truly reflect the bonding condition of sprayed concrete and surrounding rock. In addition, when the integrity of surrounding rock randomly drilled on site is poor, core sample fracture is easy to occur during core drilling, and the success rate of the site core drilling method is low.

2) Spray large plate splitting method

The splitting and pulling test has a shearing phenomenon, so that the splitting and pulling bonding strength obtained by the large-plate-spraying splitting and pulling method is higher. In addition, the rock blocks are selected to be sprayed to form the large plate on the construction site, the actual condition of the site cannot be completely reflected, and the large plate comes in and goes out of the bonding condition of the actual sprayed concrete and surrounding rocks.

3) Reserved test piece drawing method

The sprayed concrete mixed with the accelerator can quickly develop the strength of the sprayed concrete, and the 50mm wide annular groove is difficult to dig, so that the reserved test piece can be damaged when labor cost is high. And the steel pull rod is pre-embedded firstly and then concrete is sprayed, and the steel pull rod is fixed on the rock surface, so that the steel pull rod is difficult to ensure that the steel pull rod is not eccentric when being loaded. When the sprayed layer is thick, the reserved test piece is heavy, the bonding strength of the concrete which is just sprayed and the surrounding rock is low, the test piece can not be hung, and the test result of the bonding strength can not be obtained due to test failure.

In conclusion, the three existing detection methods have some problems more or less, the test value deviates from the true value, the bonding strength test value cannot truly reflect the actual bonding strength condition, and the problems that the engineering quality cannot pass the acceptance according to the actual condition of the site due to the test error and the data is forged for passing the acceptance are caused.

At present, a reserved test piece drawing method is commonly used and can reflect the field quality condition most, but no corresponding description of detection equipment about the drawing reaction force frame type and the drawing reaction force frame size exists in each specification, at present, personnel performing detection on site can make reaction force equipment according to the stress principle, basically, a beam type reaction force frame is taken as a main part, the equipment is heavy, the angle of a bearing surface cannot be adjusted, and the implementation of detection work is not facilitated.

The reaction frame used at present has the main defects that:

1 are mostly mounted on vertical rock walls-reaction frame fixation is difficult.

2 the dowel bar is difficult to be completely vertical to the bonding surface when being installed, but the reaction frame has no adjusting device and can not realize that the drawing force is coaxial with the pull rod.

3, a test surface with better flatness is difficult to find on site, the flatness is poor after the spraying is finished, and the reaction frame is difficult to align when being erected.

4 the jack and the reaction frame are heavy, and the equipment needs to be supported by a plurality of people during field operation, so the labor intensity is high.

SUMMERY OF THE UTILITY MODEL

In order to ensure the success of the bonding strength test of the field test, the utility model provides a reaction frame with a novel structure, which can ensure that the jack and the dowel bar which are arranged on the reaction frame are stressed coaxially, thereby ensuring that the stress of the bonding strength test does not deviate; and the reaction frame can be split into a plurality of parts, thereby being convenient for carrying and installation.

Particularly, the utility model provides a reaction frame that is used for on-the-spot test shotcrete and rock bonding strength, include bottom plate, load board, connect a plurality of screws of bottom plate and load board and cup joint on the screw rod and lie in load board top and the last nut and the lower nut of below respectively.

In some preferred embodiments, the bottom plate and the bearing plate are of circular ring structures; the outer diameters of the circular rings of the bottom plate and the bearing plate are the same, and the inner diameter of the circular ring of the bearing plate is smaller than that of the circular ring of the bottom plate.

In some preferred embodiments, a plurality of screw rods are uniformly connected at the edges of the bottom plate and the bearing plate.

In some preferred embodiments, there are 3 to 6 screws. In one specific embodiment, there are 4 screws.

In some preferred embodiments, the bottom plate has a screw base into which a screw can be screwed.

In some preferred embodiments, the messenger includes a plurality of stiffeners secured to the upper surface.

In some preferred embodiments, the bearing plate is provided with a groove at the center, and the diameter of the groove is larger than the inner diameter of the circular ring of the bearing plate.

In some preferred embodiments, the bearing plate is provided with through holes for receiving the screws on the periphery.

Advantageous effects

The utility model discloses a reaction frame for field test shotcrete and rock bonding strength through the angle of adjusting the upper bearing plate, reaches the coaxial function of jack and dowel steel atress to guaranteed that the atress of guaranteeing the bonding strength test does not take place the deviation. Moreover, the reaction frame can be disassembled into a plurality of parts, is convenient to carry and install, and reduces the labor intensity of field workers.

Drawings

Fig. 1 is a schematic structural view of the reaction frame of the present invention.

Fig. 2 is a schematic view of the bottom plate of the present invention.

Fig. 3 is a side view of the bottom plate of the present invention.

Fig. 4 is a schematic view of the force bearing plate of the present invention.

Fig. 5 is a side view of the force bearing plate of the present invention.

Reference numerals

The counter-force frame 100, the bottom plate 110, the screw rod base 111, the bottom plate lug plate 112, the hanging hole 113, the bearing plate 120, the groove 121, the through hole 122, the stiffening rib 123 and the screw rod 130

Detailed Description

The structures referred to in the present invention or these terms of art used are further described below. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. We do not exclude that the invention can also be implemented with other embodiments and that the structure of the invention can be changed without violating the scope of the invention.

As shown in fig. 1 to 5, the reaction frame 100 for testing the bonding strength of shotcrete and rock in situ of the present invention includes a bottom plate 110 and a bearing plate 120, wherein the bottom plate 110 and the bearing plate 120 are connected by a screw 130 and a nut. Wherein, the screw rods 130 are multiple and are connected at the edges of the bottom plate 110 and the bearing plate 120. Specifically, the base plate 110 has a plurality of screw bases 111 for inserting and fixing screws, and the screw bases 111 are uniformly distributed around the base plate 110. In one embodiment, there are 4 screws and 4 screw bases corresponding to the screws. The screw 130 is inserted into the screw base 111 and fixed. A plurality of through holes 122 sleeved with screws are uniformly distributed on the periphery of the bearing plate 120, wherein the positions of the through holes 122 correspond to the positions of the screw bases 111 on the base plate, so as to ensure that the screws 130 are in a vertical state after being connected with the base plate 110 and the bearing plate 120. In a specific embodiment, the number of through holes is 4. The screw 130 is sleeved with the lower nut 140, then sleeved with the bearing plate 120 through the through hole 122, and finally sleeved with the screw 130 and the nut 150. Thus, by adjusting the position of the upper nut 140/150 and the lower nut 140/150 on each screw 130, the upper and the lower positions of the bearing plate 120 on the screws 130 can be adjusted, and the angle of the bearing plate 120 relative to the vertically erected screws 130 can be slightly adjusted, so that the jack and the dowel bar on the bearing plate 120 can be stressed coaxially.

In some embodiments, the bottom plate 110 is a circular ring structure, and the screw bases 111 are uniformly located on the circular ring. Wherein, the screw base 111 has a recess in the middle for receiving and fixing the bottom of the screw 130.

In an embodiment of the present invention, the number of the screws 130, the screw bases 111 and the through holes 122 is 4, and these components are connected in a one-to-one correspondence. In some embodiments, the screw 130 is of dimensions Φ 25 × 140 mm.

The bearing plate 120 is also of a circular ring structure. The outer diameters of the bottom plate 110 and the circular ring of the bearing plate 120 are the same, and the inner diameter of the circular ring of the bearing plate 120 is smaller than the inner diameter of the circular ring of the bottom plate 110. In some specific embodiments, the outer diameter of the circular rings of the bottom plate 110 and the bearing plate 120 is phi 320 mm; the inner diameter of the circular ring of the bearing plate 120 is phi 50mm, and the inner diameter of the circular ring of the bottom plate 110 is phi 260 mm. The through holes 122 are uniformly distributed at the edge of the annular bearing plate 120.

The center of the bearing plate 120 is provided with a groove 121, and the diameter of the groove 121 is larger than the inner diameter of the circular ring of the bearing plate 120. In one embodiment, the groove 121 has a diameter of Φ 100 mm.

In a specific embodiment, a plurality of stiffening ribs 123 are uniformly fixed on the upper surface of the bearing plate 120. The stiffener 123 is located between the groove 121 and the through hole 122.

Also provided on the base plate 110 is an ear plate 112 projecting from the edge of the base plate, and provided in the middle thereof with a hanging hole 113, the hanging hole 112 being used for hanging on a concrete sample during the initial process of mounting the reaction frame 100 during the bonding strength test.

When the device is used, a hole with the depth of 150mm and the diameter phi of 20 is drilled on the surface of a concrete sample, a steel bar is inserted, a hanging hole 113 of a base plate of a reaction frame is hung on the steel bar, four pressure-bearing screw rods 130 are installed on the base plate 110, a pressure-bearing plate 120 is sleeved on the base plate, the reaction frame 100 is lightly pressed by hand to be tightly attached to the surface of concrete, a T-square is used for leaning against the pressure-bearing plate 120, nuts 140 and 150 of the pressure-bearing screw rods are adjusted, and the nut is screwed after the pressure-bearing plate 120 is perpendicular to a dowel steel. And (3) mounting the jack, enabling the dowel bar to penetrate through the center hole of the jack, slightly pushing the jack, enabling the bottom of the jack to fall into the circular groove 121 on the bearing plate, supporting the jack by using a lute support, and enabling the dowel bar to be located in the circle center of the center hole of the jack.

Claims

1. The reaction frame for testing the bonding strength of the sprayed concrete and the rock on site is characterized by comprising a bottom plate, a bearing plate, a plurality of screw rods for connecting the bottom plate and the bearing plate, and an upper nut and a lower nut which are sleeved on the screw rods and are respectively positioned above and below the bearing plate.

2. The reaction frame for the field test of the bonding strength of the sprayed concrete and the rock as claimed in claim 1, wherein the bottom plate and the bearing plate are of a circular ring structure; the outer diameters of the circular rings of the bottom plate and the bearing plate are the same, and the inner diameter of the circular ring of the bearing plate is smaller than that of the circular ring of the bottom plate.

3. The reaction frame for the field testing of the bonding strength of shotcrete to rock according to claim 1 wherein a plurality of threaded rods are evenly attached at the edges of the base plate and the force-bearing plate.

4. The reaction frame for the field testing of the bonding strength of shotcrete to rock according to claim 1, wherein the number of the screw rods is 3-6.

5. The reaction frame for the field testing of the bonding strength of shotcrete and rock according to claim 1, wherein the base plate has a screw base into which a screw can be screwed.

6. The reaction frame for the field testing of the bonding strength of shotcrete to rock of claim 1 wherein the force-bearing plate includes a plurality of stiffening ribs secured to the upper surface.

7. The reaction frame for in-situ testing of the bonding strength of shotcrete and rock as claimed in claim 1 wherein the bearing plate has a recess at its center, the diameter of the recess being greater than the inner diameter of the ring of the bearing plate.

8. The reaction frame for in situ testing of sprayed concrete adhesion strength to rock of claim 1, wherein the bearing plate has through holes around it for receiving screws.