CN211849649U

CN211849649U - Centrifugal model test device for measuring vertical and horizontal limit bearing capacity of pile foundation

Info

Publication number: CN211849649U
Application number: CN202020236265.2U
Authority: CN
Inventors: 刁红国; 王新泉; 崔允亮; 张天赐
Original assignee: Zhejiang University City College ZUCC
Current assignee: Zhejiang University City College ZUCC
Priority date: 2020-03-02
Filing date: 2020-03-02
Publication date: 2020-11-03
Anticipated expiration: 2030-03-02

Abstract

The utility model relates to a centrifugal model test device for measuring vertical and horizontal limit bearing capacity of a pile foundation, which comprises a model box, a transverse bracket, a first model pile, a second model pile, a first hydraulic jack, a second hydraulic jack, a first servo valve, a second servo valve, a vertical displacement sensor, a horizontal displacement sensor and model soil; the model box is divided into a main body test box and an auxiliary test box through a partition plate and an adjustable support, the transverse support is erected above the model box and comprises a long truss and a short truss, and a first base plate and a second base plate are arranged on the long truss. The utility model has the advantages that: the utility model discloses a vertical displacement sensor can directly survey the pile bolck subsides and pile body axial force distribution law under the vertical load effect at different levels with pasting the first model stake that has the foil gage, draws load-settlement curve and subsides-time curve etc. the accuracy obtains the vertical resistance to compression ultimate bearing capacity of pile foundation.

Description

Centrifugal model test device for measuring vertical and horizontal limit bearing capacity of pile foundation

Technical Field

The utility model relates to a geotechnique centrifugal model test field, concretely relates to survey centrifugal model test device of vertical and horizontal limit bearing capacity of pile foundation.

Background

Aiming at the problem of complex geotechnical engineering, the most commonly adopted test means at present comprise a field test, a scale model test, a geotechnical centrifugal model test and the like. Since soil is a material closely related to a gravity field, the properties of the soil body are also shown as stress dependence. Therefore, the geotechnical engineering centrifugal model test (overweight centrifugal model test) can improve the self weight of the model to be basically the same as that of a prototype through the centripetal acceleration generated by the high rotation of the centrifugal machine, can truly simulate the existence of a gravity field, reappear the actual stress state of engineering, shows the advantage of better conforming to the prototype property than the normal gravity small-foot model test, is the most advanced and effective test method recognized at present, and is increasingly and widely applied to the scientific research of geotechnical engineering.

At present, when a geotechnical problem related to a pile is researched by adopting a geotechnical centrifugal model test, the stress state of the pile foundation is always required to be considered. For example, when the problem of a pile foundation in projects such as a pile-supported embankment and a high-rise building is researched, the vertical acting load generated by a building (structure) on the upper part of the pile foundation needs to be considered; when the pile foundation problem in projects such as retaining walls and offshore wharfs is researched, the horizontal acting load generated by the factors such as wind power, sea waves and earthquakes borne by the pile foundation needs to be considered. When studying pile foundation problems such as pier abutment, passive pile, need consider the vertical effect load and the horizontal effect load of pile foundation simultaneously. Therefore, before relevant research is carried out by adopting a geotechnical centrifugal model test, the vertical and horizontal limit bearing capacity of the pile foundation needs to be determined, and then the stress state of the pile foundation is judged. Therefore, it is necessary to develop a centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming not enough among the prior art, providing a survey centrifugal model test device of vertical and horizontal limit bearing capacity of pile foundation, can adopt the scale model true simulation single pile vertical resistance to compression static load test and single pile horizontal static load test under the super high gravity state, the data is true reliable.

The centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation comprises a model box, a transverse support, a first model pile, a second model pile, a first hydraulic jack, a second hydraulic jack, a first servo valve, a second servo valve, a vertical displacement sensor, a horizontal displacement sensor and soil for a model; the model box is divided into a main body test box and an auxiliary test box by a clapboard and an adjustable support, the transverse bracket is erected above the model box, the transverse support comprises a long truss and a short truss, a first base plate and a second base plate are arranged on the long truss, the first model pile and the second model pile respectively comprise a pile body adhered with a semiconductor strain gauge and a pile cap arranged at the top of the pile body, the first hydraulic jack and the second hydraulic jack both comprise oil cylinders, pistons, oil inlet valves and oil return valves, the top of the model box is provided with a first servo valve, a second servo valve and a monitoring camera, the first servo valve and the second servo valve respectively comprise an oil inlet valve, an oil return valve and a control valve, the vertical displacement sensor and the horizontal displacement sensor respectively comprise a clamp block, a waveguide tube and a movable magnetic ring, and the model is horizontally paved in the main body test box by soil.

Preferably, the method comprises the following steps: the adjustable support comprises a turnbuckle, a rotary rod and a supporting seat, the rotary rod is arranged in the middle of the turnbuckle, and the supporting seats are arranged at two ends of the turnbuckle; the adjustable support is supported between the wall of the model box and the clapboard.

Preferably, the method comprises the following steps: the long truss of the transverse support spans across the model box, the short trusses are welded at two ends of the long truss, and the short trusses are anchored in sliding grooves in the top of box walls through bolts.

Preferably, the method comprises the following steps: the pile body is a hollow aluminum alloy pipe structure with the bottom sealed, the outer side of the pile body is evenly coated with a layer of epoxy resin glue for protecting the semiconductor strain gauge, and the top of the pile body is tightly connected with the pipe cap through screws.

Preferably, the method comprises the following steps: the semiconductor strain gauges are vertically distributed at equal intervals along the pile body, two pairs of semiconductor strain gauges in the same cross section are symmetrically adhered to two sides of the pile body, and the wires sequentially penetrate through the pile body micropores and the U-shaped holes at the bottom of the pipe cap and then are gathered into a bundle and finally connected to a data acquisition instrument hung on the side wall of the model box.

Preferably, the method comprises the following steps: two pairs of semiconductor strain gauges in the same cross section of the first model pile and the second model pile are connected through a Wheatstone bridge, and the semiconductor strain gauges in each pair on the same side of the first model pile and the second model pile are respectively in a vertical crossing and parallel distribution mode.

Preferably, the method comprises the following steps: the oil cylinder of the first hydraulic jack is vertically fixed in a first base plate on the transverse support, the first base plate transversely slides along a sliding groove of the long truss, the lower end of a piston of the first hydraulic jack is connected with a vertical extension rod which is adhered with a vertical pressure sensor, and the vertical extension rod and the first model pile are positioned on the same central axis; and an oil cylinder of the second hydraulic jack is horizontally fixed on a base in the auxiliary test box, the right side of a piston of the second hydraulic jack is connected with a horizontal extension rod which is pasted with a horizontal pressure sensor, and a U-shaped cushion block is arranged between the horizontal extension rod and the left pile body of the second model pile.

Preferably, the method comprises the following steps: the oil inlet valve and the oil return valve of the first servo valve are correspondingly connected with the oil inlet valve and the oil return valve of the first hydraulic jack through oil pipes, the oil inlet valve and the oil return valve of the second servo valve are correspondingly connected with the oil inlet valve and the oil return valve of the second hydraulic jack through oil pipes, and the control valve is connected to the data acquisition instrument through a lead.

Preferably, the method comprises the following steps: the wave guide of vertical displacement sensor and horizontal displacement sensor passes through anchor clamps piece and connecting rod vertical fixation respectively on first backing plate and second backing plate, and vertical displacement sensor's activity magnetic ring supports on the horizontal rib plate surface on vertical extension rod and along with its synchronous motion, and horizontal displacement sensor's activity magnetic ring supports on the right side pile body of the second model pile of earth's surface department.

The utility model has the advantages that:

1. the utility model discloses a scale model can effectively simulate the vertical resistance to compression static test of single pile and the horizontal static test of single pile, and the bearing performance of pile foundation is truly reappeared, can prevent to apply the skew and the displacement measurement error of load through the accurate positioning that slides, and data is true and reliable, provides the scientific foundation for the stress state who judges the pile foundation.

2. The utility model discloses a vertical displacement sensor can directly survey the pile bolck subsides and pile body axial force distribution law under the vertical load effect at different levels with pasting the first model stake that has the foil gage, draws load-settlement curve and subsides-time curve etc. the accuracy obtains the vertical resistance to compression ultimate bearing capacity of pile foundation.

3. The utility model discloses a horizontal displacement sensor and paste the second model stake that has the foil gage can directly survey pile bolck corner and pile body moment of flexure distribution law under the horizontal load effect at different levels, calculates pile body flexography, draws horizontal force-time-effect point displacement relation curve and horizontal force-displacement gradient relation curve etc. the accuracy obtains the critical and ultimate bearing capacity of pile foundation level.

Drawings

FIG. 1 is a front view of a centrifugal model test apparatus.

FIG. 2 is a top view of a centrifugal model test apparatus.

Fig. 3 is a schematic structural view of the adjustable support.

Fig. 4 is a schematic structural diagram of the x-axis direction, the y-axis direction and the cross section of the pile body of the first model pile (wherein, fig. a is the schematic structural diagram of the x-axis direction of the first model pile, fig. b is the schematic structural diagram of the y-axis direction of the first model pile, and fig. c is the schematic structural diagram of the cross section 1-1 of the first model pile).

Fig. 5 is a schematic structural diagram of the x-axis direction, the y-axis direction and the cross section of the pile body of the second model pile (wherein, fig. a is the schematic structural diagram of the x-axis direction of the second model pile, fig. b is the schematic structural diagram of the y-axis direction of the second model pile, and fig. c is the schematic structural diagram of the cross section 2-2 of the second model pile).

Fig. 6 is a schematic view of a method for attaching a strain gauge to a first model pile and a second model pile (where fig. a is a schematic view of the method for attaching a strain gauge to a first model pile, and fig. b is a schematic view of the method for attaching a strain gauge to a second model pile).

Fig. 7 is an enlarged schematic view of region a of fig. 1.

Fig. 8 is an enlarged schematic view of region B of fig. 1.

Fig. 9 is a schematic view of the installation of the centrifugal model test apparatus on the geotechnical centrifuge.

Description of reference numerals: 1-model box, 2-transverse support, 3-first model pile, 4-second model pile, 5-first hydraulic jack, 6-second hydraulic jack, 7-first servo valve, 8-second servo valve, 9-vertical displacement sensor, 10-horizontal displacement sensor, 11-model soil, 12-partition board, 13-adjustable support, 14-main test box, 15-auxiliary test box, 16-long truss, 17-short truss, 18-semiconductor strain gauge, 19-pile body, 20-pile cap, 21-oil cylinder, 22-piston, 23-oil inlet valve, 24-oil return valve, 25-control valve, 26-clamp block, 27-waveguide tube, 28-movable magnetic ring, 29-basket screw, 30-rotating rod, 31-supporting seat, 32-bolt, 33-epoxy resin adhesive, 34-screw, 35-wire, 36-pile body micropore, 37-U-shaped hole, 38-data acquisition instrument, 39-vertical extension rod, 40-base, 41-horizontal extension rod, 42-U-shaped cushion block, 43-connecting rod, 44-cross rib plate, 45-first cushion plate, 46-second cushion plate, 47-chute, 48-vertical pressure sensor, 49-horizontal pressure sensor, 50-monitoring camera, 51-geotechnical centrifuge, 52-hanging basket platform and 53-counterweight.

Detailed Description

The present invention will be further described with reference to the following examples. The following description of the embodiments is merely provided to aid in understanding the invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can be further modified and modified, and such modifications and modifications also fall within the protection scope of the appended claims.

The utility model provides a survey centrifugal model test device of vertical and horizontal limit bearing capacity of pile foundation, this embodiment use the friction type stake in the homogeneity soil layer as the research object, and concrete implementation method includes following step:

the method comprises the following steps:

as shown in fig. 1 and 2, a partition plate 12 made of aluminum alloy is installed in a model box 1 to divide the model box into a main body test box 14 and an auxiliary test box 15, and a plurality of adjustable supports 13 shown in fig. 3 are uniformly installed in the auxiliary test box 15 and supported between the box wall and the partition plate 12. Adjusting a rotating rod 30 of the adjustable support 13 until the partition plate 12 keeps vertical and stable, and finally sealing gaps among the partition plate 12, the box wall and the box bottom by using glass cement.

Step two:

manufacturing a first model pile 3: as shown in fig. 4, the pile body 19 is made of a hollow aluminum alloy tube, pile body micropores 36 with the diameter of 1/10 are uniformly punched on two sides of the pile body 19 in the y-axis direction from top to bottom, and the pile bottom is sealed. The aluminum alloy pile cap 20 has a circular solid upper portion and a hollow circular lower portion. The round solid body is provided with a U-shaped hole 37 along the lower left of the x-axis direction and communicated with the hollow round tube. The outer diameter of the hollow circular tube is consistent with the inner diameter of the aluminum alloy tube of the pile body, so that the pile cap 20 is just embedded in the pile body 19.

Along the y-axis direction, a pair of semiconductor strain gauges 18 is perpendicularly and crossly stuck below the pile body micropores 36 on two sides of the pile body 19, and the marked lead 35 penetrates through the pile body micropores 36 and then penetrates out of the U-shaped hole 37 along the inside of the pile body. Two pairs of semiconductor strain gauges 18 of the same cross section are connected by a wheatstone bridge as shown in fig. 6 a. After the wires 35 are completely threaded out of the U-shaped holes 37 and converged, the screws 34 on both sides of the pile body 19 are tightened to strengthen the connection with the pile cap 20, and then a layer of epoxy resin glue 33 for protecting the semiconductor strain gauge 18 is uniformly coated on the outer side of the pile body. And finally, calibrating the axial force of the pile body on a testing machine to obtain a relation curve of the axial force and the voltage of the pile body at different cross sections.

Manufacturing a second model pile 4: as shown in fig. 5, pile body micropores 36 with a diameter of 1/10 are uniformly drilled from top to bottom on two sides of the pile body 19 in the x-axis direction, and a U-shaped hole 37 is drilled on the left lower part of the circular solid body of the pile cap 20 along the x-axis direction and is communicated with the hollow circular tube.

Along the x-axis direction, a pair of semiconductor strain gauges 18 are pasted below the pile body micropores 36 on both sides of the pile body 19 in parallel. Two pairs of semiconductor strain gauges 18 of the same cross section are connected by a wheatstone bridge as shown in fig. 6 b. After the wires 35 all pass through the pile body micropores 36 and pass out of the U-shaped holes 37 along the inside of the pile body to be converged, the screws 34 on the two sides of the pile body 19 are screwed down, and then a layer of epoxy resin glue 33 for protecting the semiconductor strain gauge 18 is uniformly coated on the outer side of the pile body. And finally, calibrating the bending moment of the pile body on a testing machine to obtain a relation curve between the bending moment of the pile body and the voltage at different cross sections.

Step three:

according to the design positions of the first model pile 3 and the second model pile 4, dimension scales are marked on the inner wall of the main body test box 14 to serve as reference lines, the first model pile 3 and the second model pile 4 are positioned and installed by adopting a temporary fixing device, and a horizontal ruler assists in ensuring the verticality of the first model pile 3 and the second model pile 4. As shown in fig. 7, the semiconductor strain gauge 18 of the second model pile 4 should be aligned with the horizontal load application direction to ensure that the pile body bending moment is measured. The first model pile 3 and the second model pile 4 are located on the same horizontal line, and the pile distance is not suitable to be smaller than 6 times of the pile diameter, so that mutual influence caused by pile group effect is avoided. Subsequently, the soil 11 for a model is layered and uniformly laid by a sand rain method or the like. Finally, a first servo valve 7, a second servo valve 8 and a monitoring camera 50 are installed on the top of the model box 1, the angle of the camera is adjusted to cover most of the main body test box 14, and a data acquisition instrument 38 is installed on the outer side of the model box 1 in a hanging mode.

Step four:

as shown in fig. 1, 2 and 8, the cylinder 21 of the first hydraulic jack 5 is vertically fixed in the first pad 45, and the lower end of the piston 22 is connected to the vertical extension rod 39 to which the vertical pressure sensor 48 is attached. The transverse support 2 longitudinally slides along a sliding groove 47 at the top of the box wall of the model box 1 (in the y-axis direction), and meanwhile, the first backing plate 45 transversely slides along the sliding groove 47 of the long truss 16 (in the x-axis direction) until the vertical extension rod 39 of the first hydraulic jack 5 and the first model pile 3 are positioned on the same central axis. Subsequently, the short truss 17 and the first backing plate 45 are fixed by using the bolts 32, the oil inlet valve 23 and the oil return valve 24 of the first hydraulic jack 5 and the first servo valve 7 are correspondingly connected by using oil pipes, and the control valve 25 of the first hydraulic jack 5 is connected to the data acquisition instrument 38 by a lead.

Step five:

as shown in fig. 1, 2 and 7, the oil cylinder 21 of the second hydraulic jack 6 is horizontally installed on the base 40 in the auxiliary test box 15, the right end of the piston 22 is connected with the horizontal extension rod 41 adhered with the horizontal pressure sensor 49, so that the piston and the second model pile 4 are positioned at the same horizontal line, and the U-shaped cushion block 42 is tightly attached to the left side of the pile body, so as to prevent the epoxy resin adhesive 33 on the surface layer of the pile body from being damaged by direct contact stress. And then, correspondingly connecting the oil inlet valve 23 and the oil return valve 24 of the second hydraulic jack 6 and the second servo valve 8 by adopting oil pipes, and simultaneously connecting the control valve 25 of the second hydraulic jack 6 to a data acquisition instrument 38 through a lead. In order to prevent the oil pipe and the lead from being pulled apart during high-speed rotation, a binding belt is adopted for binding and fixing.

Step six:

as shown in fig. 9, the mold box 1 is moved to the right hand cradle platform 52 of the geotechnical centrifuge 51. As shown in FIGS. 1 and 2, the vertical displacement sensor 9 and the horizontal displacement sensor 10 are calibrated and installed, when the depth of the movable magnetic ring 28 embedded into the waveguide 27 changes, the voltage of the sensors also changes, and the pile top settlement and horizontal displacement can be calculated through the linear relation between the displacement and the voltage obtained through calibration.

As shown in fig. 1 and 8, the waveguide 27 of the vertical displacement sensor 9 is vertically fixed on the first backing plate 45 through the clamp block 26 and the connecting rod 43, and the movable magnetic ring 28 abuts against the surface of the cross rib 44 on the vertical extending rod 39 and moves synchronously therewith. After the vertical extension rod 39 is contacted with the pile cap 20, the pile top settlement of the first model pile 3 under the action of vertical loads at all levels can be measured.

As shown in fig. 1 and 7, two horizontal displacement sensors 10 are arranged in parallel up and down at the pile body adjacent to the second model pile 4 on the ground surface, so that the pile top rotating angle under the action of horizontal loads at all levels can be calculated. The waveguide 27 is vertically fixed on a second backing plate 46 through a clamp block 26 and a connecting rod 43, and the movable magnetic ring 28 abuts against the right side of the pile body 19 of the second model pile 4.

Step seven:

as shown in fig. 9, according to the total weight and moment balance relationship of the model box 1, a counterweight 53 is calculated and fixed on a basket hanging platform 52 at the left side of the geotechnical centrifuge 51. After debugging and checking are correct, the geotechnical centrifuge 51 is started to gradually accelerate to rotate to the required gravity acceleration, and the working state of the centrifuge is monitored in real time. And (3) starting the first hydraulic jack 5 and the second hydraulic jack 6 by using a remote computer through the control valves 25 of the first servo valve 7 and the second servo valve 8 respectively, and carrying out a vertical compression static load test of the first model pile 3 and a horizontal static load test of the second model pile 4 by adopting a slow maintenance load method respectively.

For the vertical compression-resistant static load test of the first model pile 3, as shown in fig. 1, after the first hydraulic jack 5 is started, the vertical extension rod 39 slowly moves downwards, and the movable magnetic ring 28 of the vertical displacement sensor 9 synchronously moves downwards along with the vertical extension rod; when the vertical extension rod 39 contacts the pile cap 20, the reading of the vertical pressure sensor 48 begins to change, and the reading of the vertical displacement sensor 9 is recorded as an initial value; subsequently, the vertical extension rod 39 continues to move downwards to apply vertical load step by step, the pile foundation is settled, and changes of the vertical pressure sensor 48 and the vertical displacement sensor 9 are recorded in the process.

For the horizontal static load test of the second model pile 4, as shown in fig. 1, the reading of the horizontal displacement sensor 10 is recorded as an initial value before the second hydraulic jack 6 is started; after starting, the horizontal extension rod 41 slowly moves to the right until contacting with the U-shaped cushion block 42, and the reading of the horizontal pressure sensor 49 begins to change; subsequently, the horizontal extension rod 41 continues to move right to apply horizontal load step by step, the pile body is horizontally displaced, and changes of the horizontal pressure sensor 49 and the horizontal displacement sensor 10 are recorded in the process.

Step eight:

according to the regulations of the relevant specifications on the slow maintenance load method, the geotechnical centrifuge 51 is closed when the test reaches the load termination condition. Processing test data of the first model pile 3, drawing a load-settlement curve, a settlement-time curve and the like, and determining the vertical compression resistance limit bearing capacity of the single pile; processing test data of the second model pile 4, drawing a horizontal force-time-action point displacement relation curve, a horizontal force-displacement gradient relation curve and the like, analyzing pile top corner and pile body bending moment distribution rules under the action of horizontal loads at all levels, calculating pile body deflection deformation, and determining single-pile horizontal critical bearing capacity, ultimate bearing capacity and the like.

Claims

1. The centrifugal model test device for measuring the vertical and horizontal limit bearing capacity of the pile foundation is characterized by comprising a model box (1), a transverse support (2), a first model pile (3), a second model pile (4), a first hydraulic jack (5), a second hydraulic jack (6), a first servo valve (7), a second servo valve (8), a vertical displacement sensor (9), a horizontal displacement sensor (10) and model soil (11); the model box (1) is divided into a main body test box (14) and an auxiliary test box (15) through a partition plate (12) and an adjustable support (13), the transverse support (2) is erected above the model box (1), the transverse support (2) comprises a long truss (16) and a short truss (17), a first base plate (45) and a second base plate (46) are arranged on the long truss (16), the first model pile (3) and the second model pile (4) respectively comprise a pile body (19) adhered with a semiconductor strain gauge (18) and a pile cap (20) arranged at the top of the pile body, the first hydraulic jack (5) and the second hydraulic jack (6) respectively comprise an oil cylinder (21), a piston (22), an oil inlet valve (23) and an oil return valve (24), a first servo valve (7), a second servo valve (8) and a monitoring camera (50) are arranged at the top of the model box (1), the first servo valve (7) and the second servo valve (8) comprise oil inlet valves (23), oil return valves (24) and control valves (25), the vertical displacement sensor (9) and the horizontal displacement sensor (10) comprise clamp blocks (26), waveguide tubes (27) and movable magnetic rings (28), and the model is horizontally paved in a main body test box (14) by soil (11).

2. The centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation according to claim 1, wherein the adjustable support (13) comprises a turnbuckle (29), a rotary rod (30) and a support seat (31), the rotary rod (30) is arranged in the middle of the turnbuckle (29), and the support seats (31) are arranged at two ends of the turnbuckle (29); the adjustable support (13) is supported between the wall of the model box (1) and the clapboard (12).

3. The centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation according to claim 1 is characterized in that the long trusses (16) of the transverse support (2) span the model box (1), the short trusses (17) are welded at two ends of the long trusses (16), and the short trusses (17) are anchored in the sliding grooves (47) at the top of the box walls through bolts (32).

4. The centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation according to claim 1, characterized in that the pile body (19) is a hollow aluminum alloy pipe structure with a sealed bottom, the outer side of the pile body (19) is uniformly coated with a layer of epoxy resin glue (33) for protecting the semiconductor strain gauge (18), and the top of the pile body (19) is fixedly connected with the pile cap (20) through a screw (34).

5. The centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation according to claim 1, characterized in that the semiconductor strain gauges (18) are vertically distributed at equal intervals along the pile body (19), two pairs of semiconductor strain gauges (18) in the same cross section are symmetrically adhered to two sides of the pile body, and the lead (35) sequentially passes through the pile body micropores (36) and the U-shaped holes (37) at the bottom of the pile cap (20) and then is gathered into a bundle and finally connected to the data acquisition instrument (38) suspended on the side wall of the model box (1).

6. The centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation according to claim 1, characterized in that the two pairs of semiconductor strain gauges (18) of the first model pile (3) and the second model pile (4) in the same cross section are connected by a Wheatstone bridge, and the semiconductor strain gauges (18) of each pair on the same side of the first model pile (3) and the second model pile (4) are respectively arranged in a vertically crossing and mutually parallel distribution mode.

7. The centrifugal model test device for measuring the vertical and horizontal limit bearing capacity of the pile foundation according to claim 1, wherein the oil cylinder (21) of the first hydraulic jack (5) is vertically fixed in a first base plate (45) on the transverse support (2), the first base plate (45) slides transversely along a sliding groove (47) of the truss frame (16), the lower end of a piston (22) of the first hydraulic jack (5) is connected with a vertical extension rod (39) adhered with a vertical pressure sensor (48), and the vertical extension rod (39) and the first model pile (3) are positioned on the same central axis; the hydraulic control system is characterized in that an oil cylinder (21) of the second hydraulic jack (6) is horizontally fixed on a base (40) in the auxiliary test box (15), a horizontal extension rod (41) adhered with a horizontal pressure sensor (49) is connected to the right side of a piston (22) of the second hydraulic jack (6), and a U-shaped cushion block (42) is arranged between the horizontal extension rod (41) and the left pile body of the second model pile (4).

8. The centrifugal model test device for measuring the vertical and horizontal limit bearing capacity of the pile foundation according to claim 1, wherein the oil inlet valve (23) and the oil return valve (24) of the first servo valve (7) are correspondingly connected with the oil inlet valve (23) and the oil return valve (24) of the first hydraulic jack (5) through oil pipes, the oil inlet valve (23) and the oil return valve (24) of the second servo valve (8) are correspondingly connected with the oil inlet valve (23) and the oil return valve (24) of the second hydraulic jack (6) through oil pipes, and the control valve (25) is connected to the data acquisition instrument (38) through a lead.

9. The centrifugal model test device for measuring the vertical and horizontal ultimate bearing capacity of the pile foundation according to claim 1, characterized in that the wave guide (27) of the vertical displacement sensor (9) and the horizontal displacement sensor (10) are respectively and vertically fixed on a first backing plate (45) and a second backing plate (46) through a clamp block (26) and a connecting rod (43), the movable magnetic ring (28) of the vertical displacement sensor (9) abuts against the surface of a cross rib plate (44) on the vertical extension rod (39) and moves synchronously therewith, and the movable magnetic ring (28) of the horizontal displacement sensor (10) abuts against the right pile body of the second model pile (4) on the ground surface.