Anti-pulling pile bearing capacity testing system and method

Abstract

The present application relates to a kind of uplift pile bearing capacity test system and method, including to be tested uplift pile, steel cross beam, support pier, bottom expansion foundation, cushion block, through jack, pulley block device, steel wire rope, tension sensor, displacement sensor, fixed clamp, reference beam and cushion stone and other structures.The present application ingeniously utilizes the principle that pulley block has labor-saving and direction-changing in physics, by setting unit pulley block consisting of movable pulley, fixed pulley and reversing pulley, in combination with the mechanical lifting action of through jack, doubling the uplift force on the top of pile is realized, and the effect of timesaving is achieved.The present application has the characteristics of high testing efficiency, safe and reliable, cost saving, etc., and can be applied to the field test of different types of uplift pile bearing capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pile bearing capacity on-site test, in particular to a uplift pile bearing capacity test system and method. BACKGROUND

[0002] The uplift pile refers to the pile drilled to counteract the upward force of water in soil when the underground structure of a building project has a part below the water level of the surrounding soil. In areas with high groundwater level, when the load of the upper structure cannot balance the upward force of the groundwater, the whole or part of the structure will be affected by the upward force. For example, the underground water tank, the basement structure of a building, the biochemical tank of a sewage treatment plant, etc. must be provided with uplift piles. At present, uplift piles have been widely used in large basement anti-floating, high-rise building / structure uplift, offshore wharf platform uplift, anchor pile foundation of suspension bridge and cable-stayed bridge, pile foundation of large dock floor and anchor pile foundation in static load test, etc.

[0003] The main mechanism of the uplift pile is to rely on the friction between the pile body and the soil layer to resist the axial tension, so the uplift bearing capacity is one of the important indicators to evaluate the performance of the uplift pile. However, in the existing uplift pile bearing capacity measurement method, a single pile vertical uplift static load test is often used, that is, counterforce piles are arranged on both sides of the pile foundation to be tested, and a single direction vertical load is directly applied through an oil pressure jack loading device to apply the uplift load to the test pile in the form of "lifting". For large-diameter, high-bearing-capacity test piles, two or more jacks are often used to load them, resulting in increased testing costs. Moreover, when two or more jacks are used for loading, in order to avoid eccentric loading of the tested pile, the jacks should be of the same type and size and should be connected in parallel and work synchronously, resulting in the problem that it is difficult to accurately control the jacks in parallel. Therefore, it is necessary to improve the existing single pile vertical uplift static load test system and develop a new uplift pile bearing capacity test system and method. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide an uplift pile bearing capacity test system and method.

[0005] The uplift pile bearing capacity test system and method comprises a test uplift pile, a steel beam, a pulley set device, a steel wire rope, a fixed clamp, a reference beam and a padstone. The pulley set device is arranged between the test uplift pile and the steel beam, the top of the steel beam is provided with a through-center jack, and the pulley set device comprises a unit pulley set and a pulley set support frame. The pulley set support frame is provided with a plurality of unit pulley sets in a ring-shaped symmetrical manner, and the unit pulley set comprises a movable pulley, a fixed pulley and a steering pulley. The pulley set support frame comprises a fixed pulley connecting ring and a steering pulley connecting ring.

[0006] The upper end of the steel wire rope is connected with the through core jack, and the lower end is wound around the unit type pulley block, and the bottom of the unit type pulley block is connected with the main reinforcement at the pile head of the pile to be tested through the movable pulley.

[0007] The fixed pulleys are connected by a fixed pulley connecting ring, and the deflection pulleys are connected by a deflection pulley connecting ring.

[0008] Preferably, the movable pulley is externally provided with a wheel frame, an upper hook and a lower hook; the upper hook is anchored with a steel wire rope, the steel wire rope is sequentially wound around the fixed pulley, the movable pulley and the deflection pulley, and the upper end of the steel wire rope is connected with the through core jack after passing through the through hole of the steel beam; the lower hook is anchored with a steel wire rope connected with the main reinforcement at the pile head of the pile to be tested.

[0009] Preferably, the movable pulley, the fixed pulley and the deflection pulley in the unit type pulley block are located on the same central axis, the movable pulley and the deflection pulley are of the same size, and the diameter of the fixed pulley is smaller than that of the movable pulley.

[0010] Preferably, supporting piers are symmetrically arranged on both sides of the pile body to be tested, and the supporting piers are provided with expanded foundation at the bottom; the steel beam is horizontally overlapped and fixed on the top of the supporting piers on both sides through the cushion block, and the supporting piers, the steel beam and the pile to be tested are located in the same horizontal section.

[0011] Preferably, the pulley block support frame comprises a connecting shaft, a fixed pulley connecting ring, a deflection pulley connecting ring, a fixed pulley connecting rod, a deflection pulley connecting rod, a fixed pulley inclined rod and a deflection pulley inclined rod; the fixed pulley connecting ring is fixed on the connecting shaft through the fixed pulley connecting rod and the fixed pulley inclined rod; the deflection pulley connecting ring is fixed on the connecting shaft through the deflection pulley connecting rod and the deflection pulley inclined rod; the connecting shaft is fixed at the center bottom of the steel beam, and the connecting shaft, the through core jack and the pile to be tested are located on the same central axis.

[0012] Preferably, a tension sensor is arranged on the main reinforcement at the pile head of the pile to be tested; displacement sensors are symmetrically installed on both sides of the pile head through the fixed clamp, and the lower part of the displacement sensor is supported on the ground surface through the reference beam and the cushion stone.

[0013] The method of the pile uplift resistance test system comprises the following steps:

[0014] Step one, installing the steel beam and the through core jack above the pile to be tested;

[0015] Step two, fixing the pulley block device at the center bottom of the steel beam;

[0016] Step three, anchoring the upper end of the steel wire rope in the through core jack in each unit type pulley block, and adjusting the length of the steel wire rope to make the movable pulley suspended in the same horizontal plane;

[0017] Step four, install the steel wire rope on the lower hook of the movable pulley, and connect it with the main reinforcement at the pile head of the pile to be tested.

[0018] Step five, install the tension sensor and displacement sensor, start the through-jack, pull and tighten the steel wire rope until the tension sensor changes; pause the through-jack, zero the tension sensor and displacement sensor, and record the initial reading.

[0019] Step six, start the through-jack again, and apply the upward load in stages using the slow load maintenance method; after the constant load is stable at each stage, record the readings of the tension sensor and displacement sensor simultaneously.

[0020] As preferred, in the step two, when making the pulley block device, first, a plurality of fixed pulleys and deflection pulleys are symmetrically arranged on the fixed pulley connecting ring and the deflection pulley connecting ring, respectively, then the fixed pulley connecting ring and the deflection pulley connecting ring are welded on the connecting shaft through the fixed pulley connecting rod and the deflection pulley connecting rod, respectively, and finally the fixed pulley diagonal rod and the deflection pulley diagonal rod are used to further reinforce and stabilize the support frame.

[0021] As preferred, in the step three, the steel wire rope is first fixed on the upper hook of the movable pulley, then passes over the fixed pulley upwards, then passes over the movable pulley downwards, then passes over the deflection pulley upwards, and finally penetrates through the through hole of the steel cross beam and is anchored in the center of the through-jack.

[0022] As preferred, in the step six, the upward load includes the upward force generated by all unit pulley blocks; after the step six is completed, step seven is further included, which specifically comprises ending the test after reaching the termination loading condition, drawing a single pile uplift static load test curve according to the upward load and the upward displacement, and determining the single pile vertical critical load and the ultimate load of the uplift pile.

[0023] The beneficial effects of the present application are:

[0024] 1) The present application ingeniously utilizes the principle of pulley block in physics, which has the functions of saving effort and changing direction, by setting a unit pulley block composed of a movable pulley, a fixed pulley and a deflection pulley, and combining with the mechanical lifting action of the through-jack, the upward force at the top of the pile is doubled, which achieves a multiplier effect.

[0025] 2) The present application uses the pulley block support frame to connect a plurality of symmetric unit pulley blocks in parallel, and improves the overall strength and stability of the support frame by setting steel members such as connecting rings, connecting rods and diagonal rods, thereby improving the structural safety during the uplift pile bearing capacity test.

[0026] 3) The pulley block device in the present application has a reasonable structure and is easy to make, and the main components can be recycled and reused, and by modifying the size of the connecting ring, connecting rod and other components, it can be applied to the uplift pile bearing capacity test of different diameters. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the anti-pulling pile bearing capacity test system.

[0028] Figure 2 It is a schematic diagram of the connection between the pulley block device and the main reinforcement of the anti-pulling pile to be tested.

[0029] Figure 3 It is a structural schematic diagram of the unit pulley block.

[0030] Figure 4 It is a schematic diagram of the A-A section in Figure 1 .

[0031] Figure 5 It is a structural schematic diagram of the pulley block support frame.

[0032] BRIEF DESCRIPTION OF DRAWINGS: 1, anti-pulling pile to be tested; 101, steel reinforcement cage; 102, pile head; 103, main reinforcement; 2, steel beam; 201, through hole; 3, supporting pier; 4, expanded base; 5, cushion block; 6, through core jack; 7, movable pulley; 701, pulley frame; 702, upper hook; 703, lower hook; 8, fixed pulley; 9, deflection pulley; 10, steel wire rope; 11, connecting shaft; 12, fixed pulley connecting ring; 13, deflection pulley connecting ring; 14, fixed pulley connecting rod; 15, deflection pulley connecting rod; 16, fixed pulley inclined rod; 17, deflection pulley inclined rod; 18 tension sensor; 19, displacement sensor; 20, fixed clamp; 21, reference beam; 22, cushion stone. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the examples. The following examples are only used to help understand the application. It should be pointed out that for ordinary people in the technical field, some modifications can be made without departing from the principles of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

[0034] Example 1

[0035] An anti-pulling pile bearing capacity test system, as shown in Figures 1 to 3 , includes an anti-pulling pile to be tested 1, a steel beam 2, a supporting pier 3, an expanded base 4, a cushion block 5, a through core jack 6, a pulley block device, a steel wire rope 10, a fixed clamp 20, a reference beam 21 and a cushion stone 22; the pulley block device includes a plurality of symmetrical unit pulley blocks and a pulley block support frame arranged between the anti-pulling pile to be tested 1 and the steel beam 2; the unit pulley block includes a movable pulley 7, a fixed pulley 8 and a deflection pulley 9; the pulley block support frame includes a connecting shaft 11, a fixed pulley connecting ring 12, a deflection pulley connecting ring 13, a fixed pulley connecting rod 14, a deflection pulley connecting rod 15, a fixed pulley inclined rod 16 and a deflection pulley inclined rod 17.

[0036] The supporting piers 3 are symmetrically arranged on both sides of the pile body 1 to be tested, and the bottom is provided with an expanded base 4; the steel cross beam 2 is horizontally overlapped and fixed on the top of the two supporting piers 3 through the cushion block 5, and the supporting piers 3, the steel cross beam 2 and the pile 1 to be tested are located in the same horizontal section. The connecting shaft 11 is fixed at the center bottom of the steel cross beam 2, and the connecting shaft 11, the through core jack 6 and the pile 1 to be tested are located on the same central axis.

[0037] The movable pulley 7 is externally provided with a wheel frame 701, an upper hook 702 and a lower hook 703; the steel wire rope 10 anchored by the upper hook 702 sequentially passes through the fixed pulley 8, the movable pulley 7 and the deflection pulley 9, and is connected with the through core jack 6 at the top of the steel cross beam 2 after passing through the through hole 201 of the steel cross beam 2; the steel wire rope 10 anchored by the lower hook 703 is connected with the main reinforcement 103 at the pile head 102 of the pile 1 to be tested. The movable pulley 7, the fixed pulley 8 and the deflection pulley 9 in the unit type pulley block are located on the same central axis, the movable pulley 7 and the deflection pulley 9 are of the same size, and the diameter of the fixed pulley 8 is slightly smaller than that of the movable pulley 7.

[0038] Embodiment Two

[0039] As another embodiment, the embodiment two proposes a more specific uplift pile bearing capacity test system based on the embodiment one, as shown in Figure 4 and Figure 5 It also includes a tension sensor 18, a displacement sensor 19,.

[0040] The fixed pulley connecting ring 12 is connected between the fixed pulleys 8, and the fixed pulley connecting ring 12 is fixed on the connecting shaft 11 through the fixed pulley connecting rod 14 and the fixed pulley inclined rod 16.

[0041] The deflection pulley connecting ring 13 is connected between the deflection pulleys 9, and the deflection pulley connecting ring 13 is fixed on the connecting shaft 11 through the deflection pulley connecting rod 15 and the deflection pulley inclined rod 17.

[0042] The tension sensor 18 is arranged on the main reinforcement 103 at the pile head 102 of the pile 1 to be tested; the displacement sensor 19 is symmetrically installed on both sides of the pile head 102 through the fixed clamp 20, and the lower part is supported on the ground surface through the reference beam 21 and the cushion stone 22.

[0043] It should be noted that the same or similar parts in the embodiment can be mutually referred, and will not be described in detail in the present application.

[0044] Embodiment Three

[0045] As another embodiment, the embodiment three proposes a method for using the uplift pile bearing capacity test system in the embodiment one or two, including the following steps:

[0046] Step 1: Clean and level the ground surface around the tensile pile 1 to be tested. Install two support piers 3 with enlarged base foundations 4 symmetrically on both sides of the tensile pile 1 to be tested. Install steel beams 2 and through jacks 6 on the top of the support piers 3. Adjust the thickness of the pads 5 to ensure the horizontality of the steel beams 2 and make the support piers 3, steel beams 2 and tensile pile 1 to be tested in the same horizontal section.

[0047] Step 2: Construct 6 sets of unit-type pulley blocks and pulley block support frames to form a pulley block device. Fix the pulley block device to the bottom center of the steel crossbeam 2 by welding or other means to ensure that the connecting shaft 11, the through-hole jack 6 and the tensile pile 1 to be tested are on the same central axis.

[0048] Step 3: As Figure 3 As shown, a steel wire rope 10 is installed on the upper hook 702 of the movable pulley 7, then passes upward over the fixed pulley 8, then downward over the movable pulley 7, upward through the steering pulley 9, and finally through the through hole 201 of the steel beam 2 and is anchored at the center of the through-hole jack 6. The length of the steel wire rope 10 is adjusted so that several movable pulleys 7 are suspended on the same horizontal plane.

[0049] Step Four: As Figure 2 As shown, a steel wire rope 10 is installed on the lower hook 703 of the movable pulley 7 to connect it to the main reinforcement 103 at the pile head 102 of the pile to be tested.

[0050] Step 5: Install the tension sensor 18 and the displacement sensor 19. The tension sensor 18 is installed on the main reinforcement 103 at the pile head 102 of the pile to be tested; the displacement sensor 19 is symmetrically installed on both sides of the pile head 102 by fixing clamps 20, and the lower part is supported on the ground surface by the reference beam 21 and the pad stone 22.

[0051] Start the through-hole jack 6 and slowly pull up and tighten the wire rope 10 until the tension sensor 18 changes. This indicates that the upward load has just begun to be applied to the pull-out pile. Pause the through-hole jack 6, zero the tension sensor 18 and the displacement sensor 19, and record the initial readings.

[0052] Step 6: Restart the through-hole jack 6 and apply the upward pull load in stages using the slow-speed sustained load method. The upward pull load at this time includes the upward pull force generated by all unit pulley blocks. After each stage of constant load is stabilized, record the readings of the tension sensor 18 and the displacement sensor 19 simultaneously.

[0053] Example 4

[0054] As another embodiment, this embodiment four presents a more specific method for using the tensile pile bearing capacity testing system, in step three:

[0055] like Figure 3As shown, the unit type pulley block comprises a movable pulley 7, a fixed pulley 8 and a steering pulley 9 located at the same central axis; the movable pulley 7 is externally provided with a wheel frame 701, an upper hook 702 and a lower hook 703.

[0056] As shown in Figure 4 and Figure 5 When the pulley block device is manufactured, first, the six fixed pulleys 8 and the steering pulleys 9 are respectively arranged in a symmetrical ring shape on the fixed pulley connecting ring 14 and the steering pulley connecting ring 15, then the fixed pulley connecting ring 14 and the steering pulley connecting ring 15 are welded on the connecting shaft 11 through the fixed pulley connecting rod 14 and the steering pulley connecting rod 15 respectively, and finally the fixed pulley inclined rod 16 and the steering pulley inclined rod 17 are used to further reinforce and stabilize the support frame.

[0057] After step six, there is still step seven, which is specifically: ending the test after reaching the termination loading condition, drawing the single pile uplift static load test curve according to the uplift load and the uplift displacement, and determining the single pile vertical critical load and the ultimate load of the uplift pile.

[0058] It should be noted that the same or similar parts in this embodiment and example three can be mutually referenced, and will not be described in detail in this application.

[0059] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the various embodiments can be mutually referenced.

Claims

1. A system for testing the bearing capacity of pull-out piles, characterized in that: It includes the anti-pulling pile (1) to be measured, the steel cross beam (2), the pulley block device, the steel wire rope (10), the fixed clamp (20), the reference beam (21) and the cushion stone (22); The pulley block device is arranged between the anti-pulling pile (1) to be measured and the steel cross beam (2), the top of the steel cross beam (2) is provided with a through core jack (6), the pulley block device includes a unit type pulley block and a pulley block support frame; The pulley block support frame is symmetrically provided with a plurality of unit type pulley blocks, the unit type pulley block includes a movable pulley (7), a fixed pulley (8) and a steering pulley (9); The pulley block support frame includes a fixed pulley connecting ring (12) and a steering pulley connecting ring (13); The upper end of the steel wire rope (10) is connected with the through core jack (6), the lower end is wound in the unit type pulley block, the unit type pulley block bottom is connected with the main reinforcement (103) at the pile head (102) of the anti-pulling pile (1) to be measured through the movable pulley (7); The fixed pulley (8) is connected by the fixed pulley connecting ring (12), and the steering pulley (9) is connected by the steering pulley connecting ring (13); The movable pulley (7) is externally provided with a wheel frame (701), an upper hook (702) and a lower hook (703); The upper hook (702) is anchored with the steel wire rope (10), the steel wire rope (10) is sequentially wound through the fixed pulley (8), the movable pulley (7) and the steering pulley (9), the upper end of the steel wire rope (10) is connected with the through core jack (6) after passing through the through hole (201) of the steel cross beam (2); The lower hook (703) is anchored with the steel wire rope (10) and connected with the main reinforcement (103) at the pile head (102) of the anti-pulling pile (1) to be measured; The pulley block support frame includes a connecting shaft (11), a fixed pulley connecting ring (12), a steering pulley connecting ring (13), a fixed pulley connecting rod (14), a steering pulley connecting rod (15), a fixed pulley inclined rod (16) and a steering pulley inclined rod (17); The fixed pulley connecting ring (12) is fixed on the connecting shaft (11) through the fixed pulley connecting rod (12) and the fixed pulley inclined rod (16); The steering pulley connecting ring (13) is fixed on the connecting shaft (11) through the steering pulley connecting rod (13) and the steering pulley inclined rod (17); The connecting shaft (11) is fixed at the center bottom of the steel cross beam (2), and the connecting shaft (11), the through core jack (6) and the anti-pulling pile (1) to be measured are located on the same central axis.

2. The uplift pile capacity testing system of claim 1, wherein: The movable pulley (7), the fixed pulley (8) and the steering pulley (9) in the unit type pulley block are located on the same central axis, the movable pulley (7) is consistent in size with the steering pulley (9), and the diameter of the fixed pulley (8) is less than that of the movable pulley (7).

3. The uplift pile capacity testing system of claim 1, wherein: The two sides of the anti-pulling pile (1) to be measured are symmetrically provided with supporting piers (3), and the supporting piers (3) are provided with expanded base (4) at the bottom; The steel cross beam (2) is horizontally lapped and fixed on the top of the two supporting piers (3) through the cushion block (5), and the supporting pier (3), the steel cross beam (2) and the anti-pulling pile (1) to be measured are located in the same horizontal section.

4. The uplift pile capacity testing system of claim 1, wherein: A tension sensor (18) is arranged on the main reinforcement (103) at the pile head (102) of the pile (1) to be tested; displacement sensors (19) are symmetrically arranged on both sides of the pile head (102) through fixed clamps (20), and the lower parts of the displacement sensors (19) are supported on the ground surface through a reference beam (21) and a cushion stone (22).

5. The method of using a pullout pile capacity testing system of any one of claims 1-4, wherein, The method comprises the following steps: Step one, erecting a steel beam (2) and a through core jack (6) above the pile (1) to be tested; Step two, fixing a pulley block device at the bottom center of the steel beam (2); Step three, anchoring the upper end of the steel wire rope (10) in each unit pulley block in the through core jack (6), and adjusting the length of the steel wire rope (10) to make the movable pulley (7) suspended in the same horizontal plane; Step four, installing the steel wire rope (10) on the lower hook (703) of the movable pulley (7) and connecting it with the main reinforcement (103) at the pile head (102) of the pile (1) to be tested; Step five, installing the tension sensor (18) and the displacement sensor (19), starting the through core jack (6), and tightening the steel wire rope (10) until the tension sensor (18) changes; pausing the through core jack (6), adjusting the tension sensor (18) and the displacement sensor (19) to zero, and recording the initial readings; Step six, starting the through core jack (6) again, and applying the upward load by the slow load maintaining method; after the constant load of each stage is applied and stabilized, the readings of the tension sensor (18) and the displacement sensor (19) are recorded synchronously.

6. The method of using a system for testing the load capacity of an uplift pile according to claim 5, wherein: In the step two, when the pulley block device is made, first, a plurality of fixed pulleys (8) and deflection pulleys (9) are symmetrically arranged on the fixed pulley connecting ring (12) and the deflection pulley connecting ring (13), respectively, then the fixed pulley connecting ring (12) and the deflection pulley connecting ring (13) are welded on the connecting shaft (11) through the fixed pulley connecting rod (14) and the deflection pulley connecting rod (15), respectively, and finally the fixed pulley inclined rod (16) and the deflection pulley inclined rod (17) are further used to reinforce and stabilize the support frame.

7. The method of using a system for testing the load bearing capacity of an uplift pile according to claim 5, wherein: In the step three, the steel wire rope (10) is first fixed on the upper hook (702) of the movable pulley (7), then passes over the fixed pulley (8) upward, then passes over the movable pulley (7) downward, then passes over the deflection pulley (9) upward, and finally penetrates through the through hole (201) of the steel beam (2) and is anchored in the center of the through core jack (6).

8. The method of using a system for testing the load bearing capacity of an uplift pile according to claim 5, wherein: In the step six, the upward load includes the upward force generated by all unit pulley blocks; after the step six is completed, step seven is further included, which is specifically to end the test after the termination loading condition is reached, draw a single pile uplift static load test curve according to the upward load and the upward displacement, and determine the single pile vertical critical load and the ultimate load of the uplift pile.

Images