An in-situ testing device for shear strength of stone retaining wall using the oblique-cut cylinder method

Abstract

An in-situ detection device for the shear strength of a stone retaining wall using an oblique cylinder method includes an oblique cylinder sample with a horizontal shear joint located in the stone retaining wall, on which a rubber gasket, a metal gasket, a hydraulic jack, a spherical support, and a reaction device are arranged in sequence; the hydraulic jack is connected to the pressure device through a hydraulic pipe; the bottom of the reaction device is buried in the stone and the rubber gasket, the metal gasket, the hydraulic jack, and the spherical support cover are arranged thereunder. The present invention applies a horizontal thrust to the oblique cylinder sample through a detection device until the oblique cylinder sample is sheared and damaged along the horizontal shear joint, and the shear strength is calculated according to the shear area, and the invention has strong practicality, accurate detection, and reasonable design.

Description

Technical Field

[0001] The invention relates to an in-situ detection device for the shear strength of a stone retaining wall using an oblique-cut cylinder method. Background Art

[0002] Gravity retaining walls have been widely used in my country. At present, most specifications only perform anti-slip stability verification, anti-overturning stability verification and foundation bearing capacity verification for gravity retaining walls. Some specifications involve the verification of the cross-section strength of the retaining wall body, and only perform eccentric compression bearing capacity verification and bending bearing capacity verification, while the verification of the shear strength of the cross-section of the retaining wall body is rarely mentioned, and usually several control sections are selected for verification. In actual engineering, there are many retaining walls, especially stone retaining walls, which are very easy to be sheared along the masonry joints due to the low mortar strength of the stone masonry or the poor construction quality. Therefore, in-situ testing of the shear strength of stone retaining walls is a very important task.

[0003] Currently, there is no standard method for in-situ testing of the shear strength of stone retaining walls, so innovative designs are needed. Summary of the invention

[0004] The present invention proposes an in-situ detection device for the shear strength of stone retaining walls using the oblique-cut cylinder method, which has strong practicality, accurate detection and reasonable design, and a detection method using the device. The device and the detection method can solve the problem that there is currently no standard method for in-situ detection of the shear strength of stone retaining walls.

[0005] The technical solution adopted by the present invention is: an in-situ detection device for the shear strength of a stone retaining wall by the beveled cylinder method, comprising a beveled cylinder sample with a horizontal shear joint located in the stone retaining wall, on which a rubber gasket, a metal gasket, a hydraulic jack, a spherical support, and a reaction device are arranged in sequence; the hydraulic jack is connected to the pressure device through a hydraulic pipe; the bottom of the reaction device is buried in the stone and the rubber gasket, the metal gasket, the hydraulic jack, and the spherical support cover are arranged thereunder. The present invention applies a horizontal thrust to the beveled cylinder sample through the detection device until the beveled cylinder sample is sheared and damaged along the horizontal shear joint, and the shear strength is calculated according to the shear area.

[0006] Furthermore, the horizontal shear joint is made of cement mortar, the top surface is an ellipse and is perpendicular to the surface of the stone retaining wall and has an intersection, and the major axis of the ellipse intersects perpendicularly with the surface of the stone retaining wall.

[0007] Furthermore, the beveled cylindrical specimen has a bottom surface connected to the stone retaining wall, the beveled surface is the surface of the stone retaining wall and is an ellipse and has an intersection with the top surface of the horizontal shear joint, the major axis of the ellipse intersects the top surface of the horizontal shear joint vertically, and the angles between the longitudinal axis of the cylinder and the beveled surface and the top surface of the horizontal shear joint are both 45°.

[0008] Furthermore, the rubber gasket is a longitudinally cut elliptical cylinder with a thickness of 3mm-5mm. The longitudinal section is parallel to the short axis of the bevel section of the beveled cylindrical specimen. The elliptical arc of the bottom surface coincides with and contacts the elliptical arc of the bevel section of the beveled cylindrical specimen and has an intersection with the top surface of the horizontal shear joint. The top surface is in contact with the metal gasket.

[0009] Furthermore, the metal gasket includes a lower longitudinally cut elliptical cylinder and an upper rectangular body; the thickness of the longitudinally cut elliptical cylinder is 3mm-5mm, the bottom surface coincides with and contacts the top surface of the rubber gasket, and the top surface is fixedly connected to the bottom surface of the rectangular body; the thickness of the rectangular body is 10mm-20mm, the top surface contacts the bottom surface of the hydraulic jack and is larger than the bottom surface of the hydraulic jack, the side surface is perpendicular to the top surface of the horizontal shear joint, and the line connecting the centers of the top and bottom surfaces is in the same straight line as the major axis of the ellipse on the top surface of the horizontal shear joint.

[0010] Furthermore, the bottom surface of the hydraulic jack contacts the metal pad, the top surface contacts the metal reaction beam through the spherical support, and the longitudinal axis is in the same straight line with the major axis of the ellipse on the top surface of the horizontal shear joint.

[0011] Furthermore, the pressure-applying device is an oil pressure pump, which is equipped with a digital pressure gauge with a peak value storage function.

[0012] Furthermore, the reaction device includes a metal reaction beam, two reaction chemical screws and a reaction nut symmetrically arranged on both sides of the metal reaction beam; the metal reaction beam is a rectangular plate, and a connecting screw hole for connecting the reaction chemical screw is drilled at each end, and the bottom surface of the metal reaction beam is in contact with the hydraulic jack through a spherical support; the bottom of the reaction chemical screw is buried in the anchor hole in the stone through chemical anchoring glue, and the top is fastened to the reaction nut through the connecting screw hole.

[0013] The beneficial effects of the present invention are as follows: (1) During the testing process, a horizontal thrust is applied to the beveled cylindrical sample through the testing device until the beveled cylindrical sample is sheared and damaged along the horizontal shear joint, and the shear strength is calculated according to the shear area. It is highly practical and accurate in testing; (2) The testing device is reasonably designed, and the instruments and spare parts used are all purchased, processed, assembled and carried conveniently, which greatly improves the promotion value; (3) It solves the problem that there is currently no standard method for in-situ testing the shear strength of stone retaining walls, and provides a reliable and practical testing method for construction quality control and repair and reinforcement design. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a front view schematic diagram of the use of the present invention.

[0015] Figure 2 It is a cross-sectional schematic diagram of the use 1-1 of the present invention.

[0016] Figure 3 It is a schematic diagram of the cross section 2-2 of the present invention.

[0017] Figure 4 It is a schematic diagram of the 3-3 cross section of the present invention.

[0018] Figure 5 It is a schematic diagram of the cross section 4-4 of the present invention.

[0019] Figure 6 It is a schematic diagram of the front elevation of the metal pad structure of the present invention.

[0020] Figure 7 It is a bottom view schematic diagram of the metal pad structure of the present invention.

[0021] Figure 8 It is a schematic diagram of drilling an oblique cylindrical sample of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0023] Reference Figure 1-8 , an in-situ detection device for the shear strength of a stone retaining wall by the beveled cylinder method, comprising a beveled cylindrical specimen 17 with a horizontal shear joint 6 located in a stone retaining wall 15, on which a rubber gasket 11, a metal gasket 7, a hydraulic jack 10, a spherical support 8, and a reaction device 18 are arranged in sequence; the hydraulic jack 10 is connected to a pressure device 13 through a hydraulic pipe 14; the bottom of the reaction device 18 is buried in the stone 5 and the rubber gasket 11, the metal gasket 7, the hydraulic jack 10, and the spherical support 8 are covered thereunder. The present invention applies a horizontal thrust to the beveled cylindrical specimen 17 through a detection device until the beveled cylindrical specimen 17 is sheared and damaged along the horizontal shear joint 6, and the shear strength is calculated according to the shear area.

[0024] The size of the stone strip 5 in this embodiment is 250 mm×250 mm×750 mm.

[0025] The horizontal shear joint 6 described in this embodiment is cement mortar, the top surface is an ellipse and is perpendicular to the surface of the stone retaining wall 15 and has an intersection. The major axis of the ellipse intersects the surface of the stone retaining wall 15 perpendicularly, the major axis of the ellipse is 200 mm, and the minor axis is 142 mm.

[0026] The beveled cylindrical specimen 17 described in this embodiment has a bottom surface connected to the stone retaining wall 15, the beveled surface is the surface of the stone retaining wall 15 and is an ellipse and has an intersection with the top surface of the horizontal shear joint 6, the major axis of the ellipse intersects the top surface of the horizontal shear joint 6 vertically, the angles between the longitudinal axis of the cylinder and the beveled surface and the top surface of the horizontal shear joint 6 are both 45°, the major axis of the ellipse is 200 mm, and the minor axis is 142 mm.

[0027] The rubber gasket 11 described in this embodiment is a longitudinally cut elliptical cylinder with a thickness of 4 mm. The longitudinal section is parallel to the short axis of the bevel section of the beveled cylindrical specimen 17. The elliptical arc of the bottom surface coincides with and contacts the elliptical arc of the bevel section of the beveled cylindrical specimen 17 and has an intersection with the top surface of the horizontal shear joint 17. The intersection is 50 mm vertically away from the longitudinal section, and the top surface is in contact with the metal pad 7.

[0028] The metal pad 7 described in this embodiment includes a longitudinally cut elliptical cylinder at the bottom and a rectangular body at the top; the thickness of the longitudinally cut elliptical cylinder is 4 mm, the bottom surface coincides with and contacts the top surface of the rubber gasket 11, and the top surface is fixedly connected to the bottom surface of the rectangular body; the thickness of the rectangular body is 12 mm, the top surface dimensions are length × height = 200 mm × 100 mm, the top surface contacts the bottom surface of the hydraulic jack 10, the side surface is perpendicular to the top surface of the horizontal shear joint 17, and the line connecting the centers of the top and bottom surfaces is in the same straight line as the major axis of the ellipse on the top surface of the horizontal shear joint 17.

[0029] The bottom surface of the hydraulic jack 10 described in this embodiment is in contact with a metal pad with a diameter of 100 mm, and the top surface is in contact with a metal reaction beam 9 through a spherical support 8, and the longitudinal axis is in the same straight line with the major axis of the ellipse on the top surface of the horizontal shear joint 17.

[0030] The pressure applying device 13 in this embodiment is a manual hydraulic pump, which is equipped with a digital pressure gauge 12 with a peak value storage function.

[0031] The reaction device 18 described in this embodiment includes a metal reaction beam 9, two reaction chemical screws 16 and a reaction nut 4 symmetrically arranged on both sides of the metal reaction beam 9; the metal reaction beam 9 is a rectangular plate with dimensions of length × width × thickness = 760mm × 100mm × 20mm, and a connecting screw hole 3 with a hole diameter of 22mm for connecting the reaction chemical screw 16 is drilled at each end, and the bottom surface is in contact with the hydraulic jack 10 through a spherical support 8. The reaction chemical screw 16 has a specification of M18 and a length of 450mm; the bottom of the reaction chemical screw 16 is buried in the anchor hole 2 in the stone 5 through a chemical anchoring glue 1, the anchor hole 2 has an inner diameter of 22mm and a depth of 160mm, and the top passes through the connecting screw hole 3 to be fastened to the reaction nut 4.

[0032] The detection steps of this embodiment are as follows: (1) Fix the adjustable angle coring machine 20 on the surface of the stone retaining wall 15, install a diamond thin-walled hollow drill bit 19 with an inner diameter of 142 mm and a length of at least 420 mm, adjust the angle and distance of the adjustable angle coring machine 20 so that the diamond thin-walled hollow drill bit 19 and the surface of the stone retaining wall 15 are at an angle of 45°, and the upper end of the diamond thin-walled hollow drill bit 19 is 200 mm away from the top surface of the horizontal shear joint 6; (2) Start the adjustable angle coring machine 20, and the diamond thin-walled hollow drill bit 19 descends to a depth of at least 290 mm to form a beveled cylindrical sample 17; (3) With the intersection of the major axis of the beveled surface of the beveled cylindrical sample 17 and the top surface of the horizontal shear joint 6 as the midpoint, use an electric hammer to symmetrically drill two anchor holes 2 in the upper and lower stones 5 on the surface of the stone retaining wall 15, pour in the quick-drying chemical anchoring glue 1, and put two reaction chemical screws The rod 16 is rotated and inserted into the anchor hole 2 and fixed, and the chemical anchor glue 1 is solidified. (4) The reaction chemical screw 16 passes through the connecting screw holes 3 at both ends of the metal reaction beam 9, and the reaction nut 4 is screwed into the reaction chemical screw 16. (5) The hydraulic jack 10 is connected to the manual hydraulic pump 13 through the hydraulic pipe 14. The rubber gasket 11, the metal gasket 7, the hydraulic jack 10, and the spherical support 8 are placed in sequence on the bevel surface of the beveled cylindrical specimen 17, so that the longitudinal axis of the hydraulic jack 10 is in the same straight line with the major axis of the ellipse on the top surface of the horizontal shear joint 6. (6) The manual hydraulic pump 13 is started to load and apply a horizontal thrust to the beveled cylindrical specimen 17 until the beveled cylindrical specimen 17 is sheared and damaged along the horizontal shear joint 6. The maximum load is read and the shear strength is calculated based on the shear area (the shear area is calculated based on the major axis of the ellipse being 200 mm and the minor axis being 142 mm).

Claims

1. An in-situ detection device for the shear strength of a stone retaining wall using an oblique-cut cylinder method, characterized in that: It comprises an oblique cylindrical specimen with a horizontal shear joint located in a stone retaining wall, on which a rubber gasket, a metal gasket, a hydraulic jack, a spherical bearing and a reaction device are arranged in sequence; the horizontal shear joint is cement mortar, the top surface is an ellipse and is perpendicular to the surface of the stone retaining wall and has an intersection, and the major axis of the ellipse intersects perpendicularly with the surface of the stone retaining wall; the bottom surface of the oblique cylindrical specimen is connected to the stone retaining wall, the oblique surface is the surface of the stone retaining wall and is an ellipse and has an intersection with the top surface of the horizontal shear joint, the major axis of the ellipse intersects perpendicularly with the top surface of the horizontal shear joint, and the angles between the longitudinal axis of the cylinder and the oblique surface and the top surface of the horizontal shear joint are all 45°; the hydraulic jack is connected to the pressure device through a hydraulic pipe; the bottom of the reaction device is buried in the stone and the rubber gasket, metal gasket, hydraulic jack and spherical bearing cover are arranged thereunder.

2. The in-situ detection device for shear strength of stone retaining wall by oblique-cut cylinder method according to claim 1, characterized in that: The rubber gasket is a longitudinally cut elliptical cylinder with a thickness of 3mm-5mm. The longitudinal section is parallel to the short axis of the bevel section of the beveled cylindrical specimen. The elliptical arc of the bottom surface coincides with and contacts the elliptical arc of the beveled cylindrical specimen and has an intersection with the top surface of the horizontal shear joint. The top surface contacts the metal pad.

3. The in-situ detection device for shear strength of stone retaining wall by oblique-cut cylinder method according to claim 1, characterized in that: The metal pad includes a longitudinally cut elliptical cylinder at the bottom and a rectangular body at the top; the thickness of the longitudinally cut elliptical cylinder is 3mm-5mm, the bottom surface is in contact with the top surface of the rubber gasket, and the top surface is fixedly connected to the bottom surface of the rectangular body; the thickness of the rectangular body is 10mm-20mm, the top surface is in contact with the bottom surface of the hydraulic jack and is larger than the bottom surface of the hydraulic jack, the side surface is perpendicular to the top surface of the horizontal shear joint, and the line connecting the centers of the top and bottom surfaces is in the same straight line as the major axis of the ellipse on the top surface of the horizontal shear joint.

4. The in-situ detection device for shear strength of stone retaining wall by oblique-cut cylinder method according to claim 1, characterized in that: The bottom surface of the hydraulic jack contacts the metal pad, the top surface contacts the metal reaction beam through the spherical support, and the longitudinal axis is in the same straight line with the major axis of the ellipse on the top surface of the horizontal shear joint.

5. The in-situ detection device for shear strength of stone retaining wall by oblique-cut cylinder method according to claim 1, characterized in that: The pressure applying device is an oil pressure pump, which is equipped with a digital pressure gauge with a peak value storage function.

6. The in-situ detection device for shear strength of stone retaining wall by oblique-cut cylinder method according to claim 1, characterized in that: The reaction device includes a metal reaction beam, two reaction chemical screws and a reaction nut symmetrically arranged on both sides of the metal reaction beam; the metal reaction beam is a rectangular plate, and a connecting screw hole for connecting the reaction chemical screw is drilled at each end, and the bottom surface of the metal reaction beam is in contact with the hydraulic jack through a spherical support; the bottom of the reaction chemical screw is buried in the anchor hole in the stone through chemical anchoring glue, and the top passes through the connecting screw hole to be fastened to the reaction nut.

7. A detection method using the in-situ detection device for shear strength of stone retaining wall by the oblique-cut cylinder method according to claim 1, characterized in that: The detection method comprises the following detection steps: (1) fixing an adjustable angle coring machine on the surface of the stone retaining wall, installing a diamond thin-wall hollow drill bit with an inner diameter of 142 mm and a length of at least 420 mm, adjusting the angle and distance of the adjustable angle coring machine so that the angle between the diamond thin-wall hollow drill bit and the surface of the stone retaining wall is 45°, and the upper end of the diamond thin-wall hollow drill bit is 200 mm away from the top surface of the horizontal shear masonry joint; (2) starting the adjustable angle coring machine, lowering the diamond thin-wall hollow drill bit to a depth of at least 290 mm, and forming an oblique cylindrical sample; (3) taking the intersection of the major axis of the oblique section of the oblique cylindrical sample and the top surface of the horizontal shear masonry joint as the midpoint, using an electric hammer to symmetrically drill two anchor holes in the upper and lower stones on the surface of the stone retaining wall, and pouring a quick-drying chemical anchoring glue into the holes. , rotate and insert the two reaction chemical screws into the anchor holes, fix them, and wait for the chemical anchor glue to solidify; (4) The reaction chemical screws pass through the connecting screw holes at both ends of the metal reaction beam, and the reaction nuts are screwed into the reaction chemical screws; (5) The hydraulic jack is connected to the manual hydraulic pump through the hydraulic pipe. Rubber gaskets, metal gaskets, hydraulic jacks, and spherical bearings are placed on the bevel surface of the beveled cylindrical specimen in sequence, so that the longitudinal axis of the hydraulic jack is in the same straight line with the major axis of the ellipse on the top surface of the horizontal shear joint; (6) Start the manual hydraulic pump to add load and apply horizontal thrust to the beveled cylindrical specimen until the beveled cylindrical specimen is sheared along the horizontal shear joint. Read the maximum load, calculate the shear area according to the major axis of the ellipse 200mm and the minor axis 142mm, and calculate the shear strength.

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