Test method and device for bonding concrete in steel hanging box sleeve and pile foundation casing

Abstract

A method and device for testing the bonding between concrete in a steel hanging box sleeve and a pile foundation casing, the test steps are as follows: (1) constructing a water pool and placing a pile foundation casing, and pouring the pile foundation casing and the water pool bottom plate into one; (2) constructing the side wall of the water pool and pouring the pile foundation concrete; (3) pasting strain gauges on the outer wall of the pile foundation casing; (4) lowering the sleeve to cover the outer periphery of the pile foundation casing, and connecting the bottom with the outer wall of the pile foundation casing by a ring plate; (5) pouring the concrete in the sleeve underwater; (6) installing a jack and a hanger device on the top of the pile foundation concrete; (7) after the age of the concrete in the sleeve reaches the requirement, pumping water to make the concrete in the sleeve emerge from the water surface, and installing a displacement monitor, and connecting the displacement monitor and the strain gauge to a data acquisition instrument; (8) using a hydraulic control system to control the jack loading, and conducting a test to obtain bonding force data. The technology can obtain the bonding force data between the concrete in the sleeve and the pile foundation casing more accurately, providing a basis for design.

Description

Technical Field

[0001] The invention relates to the technical field of concrete mechanical property test, in particular to a test method and device for bonding concrete in a steel hanging box sleeve with a pile foundation casing. Background Art

[0002] In recent years, with the vigorous development of highway construction in my country, large-scale bridges across rivers, bays, straits, etc. have emerged continuously. The construction of a large number of deep-water bridges will inevitably put forward higher requirements for the construction of bridge foundations. my country has a vast territory, and the hydrological, geological, and climatic conditions are complex and changeable. The methods and difficulty levels of bridge water foundation construction are different. Water foundation construction has many invisible unknown factors and large variables, especially the difficulty of bridge foundation construction under complex hydrogeological conditions. It has become the most critical technology in large-scale bridge construction.

[0003] In the construction of large bridges, the use of steel hanging boxes is indispensable. The steel hanging box is a temporary water-blocking structure, and its purpose is to provide a water-free environment for the processing of deep-water caps. In the process of making deep-water caps, it is usually necessary to drain the water in the steel hanging box and inject concrete into the steel hanging box. After the concrete solidifies, the deep-water cap can be obtained. When constructing the steel hanging box, the bottom plate of the steel hanging box is generally set on the outer wall of the pile foundation casing of the pile foundation. The bottom surface is surrounded by hanging box side plates, and the bottom of the steel hanging box is supported by a sleeve that is set outside the pile foundation casing and concrete is poured inside. Therefore, the bonding force between the concrete poured in the sleeve and the pile foundation casing directly affects the stability of the steel hanging box erection bearing.

[0004] Through applied research, it was found that the sleeves and concrete poured inside the sleeves currently used in construction all adopt relevant theoretical calculated values, and it is impossible to obtain a more accurate value of the bond strength between the concrete inside the sleeve and the pile foundation casing, which provides a basis for the design of the sleeves of steel hanging boxes of super-large bridges and the concrete inside the sleeves. Summary of the invention

[0005] The purpose of the present invention is to provide a test method and device for the bonding between concrete in a steel hoisting box sleeve and a pile foundation casing. The test method and device can relatively accurately obtain the bonding force data between the concrete in the sleeve and the pile foundation casing, providing a basis for the design of the steel hoisting box sleeve and the concrete in the sleeve of a super-large bridge.

[0006] In order to achieve the purpose of the present invention, the technical solution adopted is:

[0007] A method for testing the bonding between concrete in a steel hanging box sleeve and a pile foundation casing is a process of completing the test using a test device, and the test includes the following steps:

[0008] (1) When constructing a pool, cast and harden the pool bottom slab. Before casting and hardening the pool bottom slab, first locate and bury the pile foundation casing, and then cast and harden the pool bottom slab so that the bottom of the pile foundation casing forms an integral whole with the pool bottom slab.

[0009] (2) After the pool bottom slab is cast and hardened, the pool side wall construction and pile foundation concrete pouring are carried out.

[0010] (3) Paste the strain gauge on the outer wall of the pile foundation casing and connect the wires to check whether the strain gauge can work. If it does not work, it needs to be re-pasted.

[0011] (4) The sleeve is lowered and sleeved on the outer circumference of the pile foundation casing. The bottom of the sleeve is connected to the outer wall of the pile foundation casing by a ring plate.

[0012] (5) After the mortar strength of the pool side wall reaches the required level, water is poured into the pool to perform underwater pouring of concrete in the sleeve and C30 underwater pouring of concrete in the space between the sleeve and the pile foundation casing.

[0013] (6) After the pile foundation concrete has hardened, a jack is installed on the top of the pile foundation, and a hanger device for lifting the sleeve and the concrete in the sleeve is installed on the jack.

[0014] (7) When the age of the concrete in the sleeve reaches the requirement, water is pumped out to expose the concrete in the sleeve to the surface of the water, and a displacement monitor is installed on the top. The displacement monitor and strain gauge are connected to the data acquisition instrument.

[0015] (8) Use the hydraulic control system to control the jack loading. Before loading, you must check whether the hanger device is vertical, the nuts are tightened, the loading beam is horizontal, and the jack is vertical and firmly installed before loading can be carried out step by step and the test can be carried out to obtain the adhesion data.

[0016] Further preferred: the pool bottom plate at the inner wall edge of the pile foundation casing is planted with φ16 steel bars, which are 30 cm higher than the pool bottom plate and welded to the inner wall of the pile foundation casing to make the connection between the pile foundation casing and the pile foundation concrete more stable, avoiding displacement of the pile foundation casing and the pile foundation concrete during the jack loading process, which affects the test value.

[0017] Further preferably, before pouring the pile foundation concrete, the steel cage in the pile foundation casing is lowered to provide stability for the concrete structure in the pile foundation casing.

[0018] Further preferred: the test device includes a sleeve, a pile foundation casing and a pool, the pool includes a pool side wall and a pool bottom plate, the pool side wall is surrounded and arranged on the pool bottom plate; the pile foundation casing is arranged on the pool bottom plate in the pool, and the pile foundation casing is pre-buried and cast in connection with the pool bottom plate; the sleeve is sleeved outside the pile foundation casing, and a bottom support is arranged at the bottom of the sleeve and is sealed and connected to the outer wall of the pile foundation casing through a ring plate; the space between the sleeve and the pile foundation casing is cast with sleeve inner concrete, and a displacement monitor for detecting the displacement of the sleeve inner concrete and the pile foundation casing is installed on the sleeve inner concrete, a plurality of strain gauges are pasted on the outer wall of the pile foundation casing, and the strain gauges are connected to a data acquisition instrument through wires, and the inner wall of the pile foundation casing Pile foundation concrete is poured, and an upper jack and a lower jack are installed on the top of the pile foundation concrete. The upper jack and the lower jack are connected to a hydraulic control system, and the hydraulic control system controls the operation of the upper jack and the lower jack. The piston shafts of the upper jack and the lower jack are respectively supported and installed with a horizontal upper hanger and a lower hanger. The upper hanger is located above the lower hanger in a cross shape and is symmetrically arranged on the center line of the circular cross section of the pile foundation casing; a shoulder pole beam is symmetrically installed on the top of both ends of the upper hanger, and the two ends of the shoulder pole beam are connected to the sleeve through a long suspension rod; a shoulder pole beam is also symmetrically installed on the top of both ends of the lower hanger, and the two ends of the shoulder pole beam are connected to the sleeve through a short suspension rod. The hydraulic control system enables the upper jack and the lower jack to work and load in stages to realize the lifting of the upper hanger and the lower hanger, so that the long hanger and the short hanger pull the sleeve and the concrete in the sleeve and the pile foundation casing to produce relative displacement. The data read by the strain gauge and the displacement monitor under different loading forces are combined with the pressure loaded by the jack to determine the bonding force value between the concrete in the sleeve and the pile foundation casing, and complete the test of the bonding between the concrete in the sleeve and the pile foundation casing.

[0019] Further preferred: the upper ends of the long suspension rod and the short suspension rod are respectively limited on the shoulder pole beam by a nut pad and a locking nut, so as to facilitate the installation and adjustment of the long suspension rod and the short suspension rod.

[0020] Further preferred: the water pool is built in a foundation pit, and concrete is poured at the bottom of the foundation pit as the water pool bottom plate. After the mortar strength of the water pool side wall reaches the requirement, the outer side of the water pool side wall is backfilled with external fill soil to fill the foundation pit outside the water pool side wall.

[0021] Further preferably, a support frame is provided at the bottom of the upper jack. The arrangement of the support frame enables the upper jack and the lower jack to adopt jacks of the same specification.

[0022] Further preferably, the displacement monitor is a micrometer or a displacement meter.

[0023] The bonding test method and device of the concrete in the sleeve of the steel hanging box and the pile foundation casing can be tested according to the actual structural dimensions using a full-scale model, and the hydraulic system is used to apply graded pressurization. When the displacement between the pile foundation casing and the concrete in the sleeve is recorded, the vertical distribution of the bonding force between the pile foundation casing and the bottom concrete is measured using a strain gauge, and the state of the structural destruction process is recorded. The force applied by the jack is the bonding force between the pile foundation casing and the concrete. The bonding force value between the concrete in the sleeve and the pile foundation casing is determined, and the bonding force data between the concrete in the sleeve and the pile foundation casing can be obtained more accurately, providing a basis for the design of the sleeve of the steel hanging box of the super-large bridge and the concrete in the sleeve, and also providing a design basis for the bottom-free concrete steel hanging box. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the device layout used in the test of the bonding mechanism between the concrete in the hanging box sleeve and the pile foundation casing of Bengang;

[0025] Figure 2 for Figure 1 Schematic diagram of the left side;

[0026] The names corresponding to the numbers in the figure are:

[0027] 1. External fill; 2. Side wall of the pool; 3. Sleeve; 4. Strain gauge; 5. Displacement monitor; 6. Pile foundation casing; 7. Shoulder beam; 8. Locking nut; 9. Short hanger; 10. Lower hanger; 11. Lower jack; 12. Long hanger; 13. Upper hanger; 14. Upper jack; 15. Support frame; 16. Nut pad; 17. Hydraulic control system; 18. Data acquisition instrument; 19. Bottom support; 20. Ring plate; 21. Pool bottom plate. DETAILED DESCRIPTION

[0028] In order to describe the present technology more clearly, the present technology is further described in detail below with reference to the accompanying drawings and embodiments.

[0029] Example 1

[0030] The following steps can be used to complete the bonding mechanism test between the concrete in the steel hanging box sleeve and the pile foundation casing:

[0031] (1) Constructing a pool, casting and hardening the pool bottom plate, positioning and burying the pile foundation casing before casting and hardening the pool bottom plate, and then casting and hardening the pool bottom plate so that the bottom of the pile foundation casing and the pool bottom plate are integrated; the pool bottom plate at the inner wall edge of the pile foundation casing is planted with φ16 steel bars, which are 30 cm higher than the pool bottom plate and welded to the inner wall of the pile foundation casing.

[0032] (2) After the pool bottom slab is cast and hardened, the pool side wall construction and pile foundation concrete pouring are carried out. Before pouring the pile foundation concrete, the steel cage in the pile foundation casing is lowered.

[0033] (3) Paste the strain gauge on the outer wall of the pile foundation casing and connect the wires to check whether the strain gauge can work. If it does not work, it needs to be re-pasted.

[0034] (4) The sleeve is lowered and sleeved on the outer circumference of the pile foundation casing. The bottom of the sleeve is connected to the outer wall of the pile foundation casing by a ring plate.

[0035] (5) After the mortar strength of the pool side wall reaches the required level, water is poured into the pool to perform underwater pouring of concrete in the sleeve and C30 underwater pouring of concrete in the space between the sleeve and the pile foundation casing.

[0036] (6) After the pile foundation concrete has hardened, a jack is installed on the top of the pile foundation, and a hanger device for lifting the sleeve and the concrete in the sleeve is installed on the jack.

[0037] (7) When the age of the concrete in the sleeve reaches the requirement, water is pumped out to expose the concrete in the sleeve to the surface of the water, and a displacement monitor is installed on the top. The displacement monitor and strain gauge are connected to the data acquisition instrument.

[0038] (8) Use the hydraulic control system to control the jack loading. Before loading, you must check whether the hanger device is vertical, the nuts are tightened, the loading beam is horizontal, and the jack is vertical and firmly installed before loading can be carried out step by step and the test can be carried out to obtain the adhesion data.

[0039] The test device comprises a sleeve 3, a pile foundation casing 6 and a pool, wherein the pool comprises a pool side wall 2 and a pool bottom plate 21, wherein the pool side wall 2 is arranged on the pool bottom plate 21; wherein the pile foundation casing 6 is arranged on the pool bottom plate 21 in the pool, and the pile foundation casing 6 is pre-buried and cast in connection with the pool bottom plate 21; wherein the sleeve 3 is sleeved outside the pile foundation casing 6, and a bottom support 19 is arranged at the bottom of the sleeve 3 and is sealed and connected with the outer wall of the pile foundation casing 6 through a ring plate 20; wherein the space between the sleeve 3 and the pile foundation casing 6 is cast with sleeve inner concrete, and a displacement monitor 5 for detecting the displacement of the sleeve inner concrete and the pile foundation casing 6 is installed on the sleeve inner concrete, and a plurality of strain gauges 4 are pasted on the outer wall of the pile foundation casing 6, and the strain gauges 4 are connected with a data acquisition instrument 18 through a wire, and the pile foundation casing 6 is cast with pile foundation concrete An upper jack 14 and a lower jack 11 are installed on the top of the pile foundation concrete. The upper jack 14 and the lower jack 11 are connected to a hydraulic control system 17. The hydraulic control system 17 controls the operation of the upper jack 14 and the lower jack 11. The piston shafts of the upper jack 14 and the lower jack 11 are respectively supported and installed with a horizontal upper hanger 13 and a lower hanger 10. The upper hanger 13 is located above the lower hanger 10 and is in a cross shape, and is symmetrically arranged on the center line of the circular cross section of the pile foundation casing 6; a shoulder pole beam 7 is symmetrically installed on the top of both ends of the upper hanger 13, and the two ends of the shoulder pole beam 7 are connected to the sleeve 3 through a long suspension rod 12; a shoulder pole beam 7 is also symmetrically installed on the top of both ends of the lower hanger 10, and the two ends of the shoulder pole beam 7 are connected to the sleeve 3 through a short suspension rod 9.

[0040] The upper ends of the long suspension rod 12 and the short suspension rod 9 are respectively limited on the shoulder beam 7 by means of a nut backing plate 16 and a locking nut 8 .

[0041] The pool is built in a foundation pit, and concrete is poured at the bottom of the foundation pit as the pool bottom plate 21. After the mortar strength of the pool side wall 2 reaches the requirement, the outer fill soil 1 is backfilled outside the pool side wall 2 to fill the foundation pit outside the pool side wall 2.

[0042] The bottom of the upper jack 14 is padded with a support frame 15 .

[0043] The displacement monitor 5 is a micrometer or a displacement meter.

[0044] The actual application test records are as follows:

[0045] The test was carried out in an open space next to the bridgehead of the steel trestle on the Du'an side of the main Hongshui River Bridge. An excavator was used to level the site.

[0046] 1.1 Pool design

[0047] The pool is 5×5×2.2m in size, with a clearance of 4.6×4.6m on the inner wall. The designed pool depth is 2.2m, the pool is buried 1m deep and 1.2m above the ground. It is built with 400×200×200mm concrete bricks, the bottom plate is poured with 15cm thick concrete, and the inner wall of the pool is cemented. A total of 528 concrete bricks are used. The bottom concrete layer is 2.704m³.

[0048] After leveling the site, a pit with a length and width of 5.2×5.2m and a depth of 1.1m was excavated, with an excavation volume of 29.744m³. The side walls of the pool were built from the bottom of the pit to a height of 1.2m above the ground. After the side walls were built, the gaps between the side walls were backfilled with 2m³ of backfill soil.

[0049] 1.2 Design of sleeve reaction device

[0050] The sleeve used in this test adopts the design size of the steel hanging box sleeve of the Hongshui River Bridge. The pile foundation casing is consistent with the design size. The pile foundation casing with a diameter of 2.4m is rolled with 14mm thick steel plate. The casing height is 2.5m. Concrete is poured in the casing. The concrete volume is 10.4m³. The pile foundation casing is processed and lowered according to the design. The 2.2 pile diameter steel cage is planted at the bottom of the inner wall of the pile foundation casing to strengthen the bonding between the inner wall of the pile foundation casing and the concrete; considering that the underwater concrete pouring in the test sleeve is lower than the water pressure at the bridge position during actual on-site construction, the actual construction underwater concrete density is better than the test, and the test conditions are more conservative. The reaction device is set with four hanging points, the hanger rod is made of φ40 fine-rolled threaded steel, and the hanger is made of double-jointed 63#a I-beam.

[0051] 1.3 Test equipment

[0052] 4 jacks and their supporting equipment, 12 strain gauges, a strain data acquisition instrument, 8 micrometers (or displacement meters), 50m patterned wire, an electric soldering iron, a roll of welding wire, a bottle of AB glue each, a piece of abrasive paper, a wire brush, a bottle of industrial alcohol, a bag of cotton balls, and a bottle of 502 glue.

[0053] 1.4 Test Principle

[0054] Use a pressure gauge to apply pressure in stages and record the force applied by the jack when displacement occurs between the steel pipe and concrete, which is the bonding force between the steel plate and concrete. Use a strain gauge to measure the vertical distribution of the bonding force between the pile foundation casing and the bottom concrete. And record the state of the structural destruction process.

[0055] Strain gauges are arranged along the height direction of the outer wall of the pile foundation casing to measure the distribution of the bonding force between the pile foundation casing and the bottom concrete along the height direction. The arrangement method is as follows: strain gauges are arranged at three sections along the height direction of the outer wall of the pile foundation casing, with four strain gauges arranged in each section, and they are pasted parallel to the longitudinal direction of the pile foundation casing, with the upper and lower layers 20 cm away from the top and bottom surfaces of the concrete in the sleeve.

[0056] Four displacement test points are symmetrically arranged on the top surface of the concrete in the sleeve to test the relative displacement between the concrete in the sleeve and the pile foundation casing.

[0057] 1.5 Test steps

[0058] (1) Place the pile foundation casing in the actual construction environment water for 30 days;

[0059] (2) Clean the attachments on the inner wall of the pile foundation casing, excavate the test site, carry out foundation treatment, foundation pouring and burying the pile foundation casing;

[0060] (3) Pouring pile foundation concrete;

[0061] (4) Remove the attachments on the surface of the pile foundation casing, remove the rust on the corresponding position of the strain gauge on the outer wall of the pile foundation casing, paste the strain gauge, weld the lead wire, and number the strain gauge;

[0062] (5) Place the sleeve in the corresponding position of the pile foundation casing and fix it. During the placement process, the strain gauge needs to be protected to prevent the sleeve from colliding with the strain gauge and causing damage to the strain gauge; fill water into the test pool, pour concrete in the sleeve to simulate underwater concrete pouring, and keep a sample as a test block;

[0063] (6) When the strength of the bottom concrete is not less than 95% and the curing time reaches 7 days, arrange the test equipment and conduct the test. Use the jack to load in stages, pull out the sleeve and the concrete inside the sleeve, and measure and record the relevant data.

[0064] 1.6 Measurement point arrangement

[0065] Strain gauges are arranged at three sections along the high direction of the outer side of the pile foundation casing, with four strain gauges arranged in each section. They are pasted parallel to the longitudinal direction of the pile foundation casing, and the upper and lower layers are 20 cm away from the top and bottom surfaces of the concrete in the sleeve; four displacement test points are symmetrically arranged on the top surface of the concrete in the sleeve, and four steel bars are embedded in advance, with 10 cm of the steel bars exposed and 20 cm buried in the concrete. After the water in the pool is pumped out, the steel bar heads are cut and polished, leaving 2 cm exposed.

[0066] 1.7 Estimation

[0067] The estimated destructive force is 390t with a friction coefficient of 300kPa, and two jacks are used for synchronous loading. According to relevant research, the friction coefficient can reach 600kPa. According to this parameter, the destructive force will reach 784t, and the sleeve has a hoop effect. According to the steel tube concrete bonding mechanism, its bonding effect will be stronger.

[0068] 1.8 Loading method

[0069] Appropriately increase the graded load within the linear change range, and load 10t each time in the change section; load 10t in the first stage to check whether the test equipment and loading equipment are normal and whether the structure is firm; the first stage loading is divided into 3 levels of 20t per level to load to 100t; the second stage loading is divided into 3 levels of 20t per level to load to 160t; after 160t, load 10t per level until the component is destroyed; record the relative displacement between the concrete in the sleeve and the pile foundation casing at each level of loading; and the strain under each level of load; record the structural morphology under each level of load to determine the bonding value between the concrete in the sleeve and the pile foundation casing.

[0070] The above description is not a limitation of the present application, and the present application is not limited to the above examples. Any changes, modifications, additions or substitutions made by technicians in this field within the essential scope of the present application should fall within the scope of protection of the present application.

Claims

1. A test method for bonding concrete in a steel hanging box sleeve with a pile foundation casing, characterized in that: It is the process of completing the test using a test device, which includes the following steps: (1) Construct a pool and cast and harden the pool bottom slab. Before casting and hardening the pool bottom slab, first locate and bury the pile foundation casing, and then cast and harden the pool bottom slab so that the bottom of the pile foundation casing is integrated with the pool bottom slab; (2) After the pool bottom slab is cast and hardened, the pool side wall construction and pile foundation concrete pouring are carried out; (3) Paste the strain gauge on the outer wall of the pile foundation casing and connect it to test whether the strain gauge can work. If it does not work, re-paste it; (4) The sleeve is lowered and sleeved on the outer periphery of the pile foundation casing, and the bottom of the sleeve is connected to the outer wall of the pile foundation casing by a ring plate; (5) After the mortar strength of the pool side wall reaches the requirement, water is poured into the pool to perform underwater pouring of concrete in the sleeve and C30 underwater pouring of concrete in the space between the sleeve and the pile foundation casing; (6) After the pile foundation concrete has hardened, a jack is installed on the top of the pile foundation, and a hanger device for lifting the sleeve and the concrete in the sleeve is installed on the jack; (7) When the age of concrete in the sleeve reaches the requirement, pump water to make the concrete in the sleeve emerge from the water surface, and install a displacement monitor on the top. The displacement monitor and strain gauge are connected to the data acquisition instrument; (8) Use the hydraulic control system to control the jack loading. Before loading, it is necessary to check whether the hanger device is vertical, whether the nut is tightened, whether the loading beam is horizontal, whether the jack is vertical and installed firmly before loading step by step and conducting tests to obtain the bonding strength data; The test device comprises a sleeve (3), a pile foundation casing (6) and a pool, wherein the pool comprises a pool side wall (2) and a pool bottom plate (21), wherein the pool side wall (2) is arranged on the pool bottom plate (21); the pile foundation casing (6) is arranged on the pool bottom plate (21) in the pool, and the pile foundation casing (6) is connected to the pool bottom plate (21) by pre-embedded casting; the sleeve (3) is sleeved outside the pile foundation casing (6), and a bottom support is arranged at the bottom of the sleeve (3) (19) and is sealed and connected to the outer wall of the pile foundation casing (6) through a ring plate (20); the space between the sleeve (3) and the pile foundation casing (6) is cast with sleeve concrete, and a displacement monitor (5) for detecting the displacement of the sleeve concrete and the pile foundation casing (6) is installed on the sleeve concrete; a plurality of strain gauges (4) are attached to the outer wall of the pile foundation casing (6), and the strain gauges (4) are connected to a data acquisition instrument (18) through wires; the pile foundation casing (6) is cast with pile foundation concrete, and an upper jack (14) and a lower jack (11) are installed on the top of the pile foundation concrete; the upper jack (14) and the lower jack (11) are connected to a hydraulic control system (17), and the hydraulic control system (17) controls the operation of the upper jack (14) and the lower jack (11); and the piston shafts of the upper jack (14) and the lower jack (11) are respectively supported and installed with a horizontal upper hanger (13) and a lower hanger (10), the upper hanger (13) is located above the lower hanger (10) and is in a cross shape; a shoulder pole beam (7) is symmetrically installed at the top of both ends of the upper hanger (13), and the two ends of the shoulder pole beam (7) are connected to the sleeve (3) through a long suspension rod (12); and a shoulder pole beam (7) is also symmetrically installed at the top of both ends of the lower hanger (10), and the two ends of the shoulder pole beam (7) are connected to the sleeve (3) through a short suspension rod (9).

2. The bonding test method between concrete in the steel hanging box sleeve and pile foundation casing according to claim 1 is characterized by: The pool bottom plate at the inner wall edge of the pile foundation casing is planted with φ16 steel bars, which are 30 cm higher than the pool bottom plate and are welded to the inner wall of the pile foundation casing.

3. The bonding test method between concrete in the steel hanging box sleeve and the pile foundation casing according to claim 1 is characterized by: Before pouring the pile foundation concrete, lower the steel cage inside the pile foundation casing.

4. The bonding test method between concrete in the steel hanging box sleeve and the pile foundation casing according to claim 1 is characterized by: The upper ends of the long suspension rod (12) and the short suspension rod (9) are respectively limited on the shoulder pole beam (7) by means of a nut backing plate (16) and a locking nut (8).

5. The bonding test method between concrete in the steel hanging box sleeve and the pile foundation casing according to claim 1 is characterized by: The water pool is built in a foundation pit, and concrete is poured at the bottom of the foundation pit as a water pool bottom plate (21). After the mortar strength of the water pool side wall (2) reaches the required level, the outer fill soil (1) is backfilled on the outer side of the water pool side wall (2) to fill the foundation pit on the outer side of the water pool side wall (2).

6. The bonding test method between concrete in a steel hanging box sleeve and a pile foundation casing according to claim 1, characterized in that: The bottom of the upper jack (14) is provided with a support frame (15).

7. The bonding test method between concrete in a steel hanging box sleeve and a pile foundation casing according to claim 1, characterized in that: The displacement monitor (5) is a micrometer or a displacement meter.

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