CN109736364B - Calcareous sand pile foundation model test system capable of simulating wind wave torsion action - Google Patents

Abstract

The invention discloses a calcareous sand pile foundation model test system capable of simulating wind wave torsion action, and relates to the field of rock-soil mechanical tests. The structure of the invention is as follows: the torsional load applying unit (900) comprises a left connecting rod (910), a torsional load left half part (920), a torsional load right half part (930) and a right connecting rod (940); the torsional load left half part (920) and the torsional load right half part (930) are respectively arranged on two sides of the pile foundation pressure chamber unit (200); is connected with the upper-back type bracket (111) through a left connecting rod (910) and a right connecting rod (930) arranged at the upper part of the upper-back type bracket; the gear (0510) is connected with the model pile upper cap (051) of the model pile (050) through a torsion fixing screw (0511). The system is used for measuring the ultimate bearing capacity of the pile foundation and simulating the settlement and bearing characteristics of the pile foundation under the horizontal torsion environmental load in the service process of the pile foundation.

Description

Calcareous sand pile foundation model test system capable of simulating wind wave torsion action

Technical Field

The invention relates to the field of rock-soil mechanical tests, in particular to a calcareous sand pile foundation model test system capable of simulating the wind wave torsion action.

Background

The implementation and the promotion of the marine island engineering construction in China are vital to the economic, military and civil career of China; various engineering geological problems are encountered in the process of carrying out island reef engineering construction, and pile foundation engineering is a common treatment means for foundation treatment in island reef construction. In the pile foundation engineering, the bearing capacity of the pile foundation is generally required to be detected and analyzed, so that the ultimate bearing capacity of the pile foundation is determined, and meanwhile, the influence of environmental load in a service environment on the safety and stability of the pile foundation is also required to be considered. On one hand, for the construction of the bearing capacity of the pile foundation, a pile testing method is commonly adopted in the engineering; the method is characterized in that a low-speed load maintaining method of a pile foundation static load test is adopted, and the pile test in the actual engineering is time-consuming and labor-consuming; however, the engineering building in the marine environment often needs to bear dynamic load with a certain frequency, so that the safety is required to perform pile foundation engineering tests in both dynamic and static loads. The dynamic load test pile is characterized in that the load needs to be repeatedly loaded and unloaded. During the test of actual engineering pile usually adopt the mode of heavy object pile pressure to apply the load to the pile foundation, if carry out the sound load pile foundation engineering test of certain cycle number, its manpower, material resources cost are higher. On the other hand, the pile foundation in the marine dynamic environment can usually obtain the natural environment load data in the environment through an observation method, but how to better simulate the application of the environment load is very challenging work, especially the calcareous sand pile base model test related to the marine environment. For example, an island pile foundation located in a marine environment is often acted by various wind and wave power loads, however, the wind and wave power loads often have the characteristics of changeable size and direction, even changeable acting points, and meanwhile, the repeated water level lifting of waves can also cause the change of soil body strength, so that the bearing capacity of the pile foundation is influenced, and how to better simulate the wind and wave loads is a very important thing. In the engineering test pile, it is very difficult to realize the simulation of the environmental load by some loading mode. And the indoor model test adopts similar principle, through certain reduced scale proportion, develops the pile foundation test in the model case, and the pile foundation model test can better analysis relevant conclusion to confirm and judge the relevant law that the pile foundation bore. The conventional geotechnical model box generally has a certain size and better effect; the method is characterized in that an indoor model test mode is usually adopted to simulate the pile foundation environmental load, in the collection of parameters, model box tests are usually carried out through detection means such as embedding sensors, and the model box tests are gradually accepted by people through years of practice methods and are improved, more environmental load factors can be considered, the parameters are convenient to collect, and the workload can be greatly reduced. At present, the triaxial test device for the pile foundation model is a new way and direction by utilizing the triaxial, and the triaxial test device for the pile foundation model is developed by utilizing an indoor small geotechnical test device, so that the triaxial test device has the advantages of accurate sample installation, small workload, convenient data acquisition and the like.

Disclosure of Invention

The invention aims to provide a calcareous sand pile foundation model test system capable of simulating the wind wave torsion action, which can simulate the stress state of a model pile under a confining pressure state in a triaxial pressure chamber, apply upper constant static load to the model pile so as to determine the ultimate bearing capacity of the model pile, can simulate the actions of various environmental loads such as wind, wave and the like on the pile, such as the actions of multidirectional torsion loads on the pile, and can apply a cyclic load and static loads with different sizes to the model pile so as to simulate a real engineering load state.

The purpose of the invention is realized by the following steps:

specifically, the system comprises a test object, namely a pile foundation unit;

the device is provided with a bracket, a pile foundation pressure chamber unit, a dynamic and static load applying unit, a strain control unit, a water pressure loading unit, a power source unit, a soil consolidation stress ratio applying unit, a torsional load applying unit, a data acquisition instrument and a computer;

the torsion load applying unit comprises a left connecting rod, a torsion load left half part, a torsion load right half part and a right connecting rod;

the left torsional load half part and the right torsional load half part are respectively arranged on two sides of the pile foundation pressure chamber unit; the upper part of the upper connecting rod is provided with a left connecting rod and a right connecting rod which are connected with the upper returning bracket; the gear is connected with the model pile upper cap of the model pile through a torsion fixing screw;

the left half part of the torsional load is formed by sequentially connecting a left air cylinder, a 1 st left torsional pressure sensor, a left torsional T-shaped iron ruler and a left rack, and a torsional left 1 st displacement meter and a torsional left 2 nd displacement meter are respectively arranged at two ends of the left torsional T-shaped iron ruler;

the right half part of the torsional load is formed by sequentially connecting a right cylinder, a2 nd right torsional pressure sensor, a right torsional T-shaped iron ruler and a right rack, and a torsional right 3 rd displacement meter and a torsional right 4 th displacement meter are respectively arranged at two ends of the right torsional T-shaped iron ruler.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the method comprises the following steps that firstly, a soil foundation part and model piles jointly form a pile foundation unit as a detection object of a system, and a water pressure loading unit and a consolidation stress ratio applying unit can simulate the soil stress state in the natural environment of the pile foundation unit more truly and are closer to the application environment of the engineering pile foundation;

the dynamic and static load applying unit and the torsional load applying unit in the system can respectively apply different types of loads on the model pile through switching, so that multifunctional load application is realized, the multiple types of loads in the service environment of the pile foundation are complete in function, and the operation switching is convenient and fast;

the system is provided with a universal sensor, the output end of the universal sensor is connected with a data acquisition instrument in order to acquire corresponding data parameters, and the data acquisition instrument stores the acquired data in a computer, so that the analysis is more precise and accurate.

In a word, the system comprises a function part and a detection part, wherein the function part comprises the self stress state of the pile foundation unit in the environment, then a multifunctional load is applied to the pile foundation unit, and the stress and vertical settlement parameters of the pile foundation unit are detected through embedded sensors and other general elements, so that the system is a multifunctional, convenient and quick pile foundation model test system; the method is used for measuring the ultimate bearing capacity of the pile foundation and simulating the settlement and bearing characteristics of the pile foundation under the conditions of environmental load and engineering load applied to the service process of the pile foundation.

Drawings

FIG. 1 is a block diagram of the architecture of the present system;

FIG. 2 is a schematic structural diagram of the present system;

fig. 3 is a schematic structural diagram of a pile foundation unit 000;

fig. 4 is a schematic structural view of a model pile 050;

figure 5 is an exploded schematic view of the model post 050;

FIG. 6 is a schematic structural view of the stent 100;

fig. 7 is a block diagram of a pile foundation pressure chamber unit 200; fig. 8 is a cross-sectional view of pile foundation pressure chamber unit 200;

fig. 9 is a schematic view of the pile foundation pressure chamber unit 200; FIG. 10 is a schematic view of the structure of the chassis 230;

FIG. 11 is a schematic view of the structure of the seal 240; fig. 12 is an installation schematic of pile foundation pressure chamber unit 200;

fig. 13 is a schematic structural view of the dynamic and static load applying unit 300;

fig. 14 is an installation schematic view of the dynamic and static load applying unit 300;

fig. 15 is a sectional view of the dynamic and static load applying unit 340;

fig. 16 is a schematic structural view of the strain control unit 500;

fig. 17 is a schematic structural view of the water pressure loading unit 600;

fig. 18 is an operation principle diagram of the water pressure loading unit 600;

fig. 19 is a schematic structural view of the power source unit 700; fig. 20 is a schematic view of the power source unit 700;

fig. 21 is a schematic structural view of a consolidation stress ratio applying unit 800;

FIG. 22 is a schematic diagram of the structure of the pressure application module 830;

fig. 23 is an installation schematic of pile foundation pressure chamber unit 200;

fig. 24 is a block diagram showing the structure of a torsional load applying unit 900;

fig. 25 is a schematic structural view of the torsional load applying unit 900;

FIG. 26 is a schematic view of the structure of the torsional load left half 920;

FIG. 27 is a schematic view of the structure of the torsional load right half 940;

FIG. 28 is a diagram illustrating detection of a force condition.

In the figure:

000, the number of the pile foundation units,

010-pile side soil, 020-pile end soil, 030-rubber membrane, 040-soil sample cap,

050-a model pile,

051-upper cap of model pile, 052-pin, 0531-left half part of model pile,

0532-the right half part of the model pile, 054-the lower cap of the model pile, 055-the soil pressure box,

056-strain gauge, 057-wire outlet, 058-level bar, 059-potentiometer, 0510-gear,

0511-twisting the fixing screw.

100-a support, wherein the support is provided with a plurality of brackets,

110-a clip-shaped bracket, wherein,

111-top-return type support; 112-middle-clip type bracket; 113-lower clip type bracket;

120-lead screw;

130-a support plate;

140 — slide.

200-a pile foundation pressure chamber unit,

220-an upper glass cover, wherein,

221-an upper glass cover is covered on the disk surface,

222-a glass cylinder, the glass cylinder,

223-the lower disc surface of the upper glass cover,

224-a fixed lead screw, which is fixed,

225-fixing nut;

230-a base plate, wherein the base plate is provided with a plurality of grooves,

231-the 1 st confining pressure hole, 232-the 2 nd confining pressure hole,

233-1 st hole, 234-2 nd hole;

240-the sealing member or members-are,

241-convex sealing body, 242-1 st sealing ring, 243-2 nd sealing ring, and 244-circular nut.

300-a dynamic and static load applying unit,

310-a dynamic and static cylinder;

320-dynamic and static dowel bars.

330-the support baffle is arranged on the upper surface of the frame,

331-1 st press-pull supporting diaphragm,

332-2 nd press-and-pull support baffle,

333-3 rd press-pull supporting partition board,

334-pressing and pulling the vertical screw rod,

335-pressing and pulling the locking nut;

340-pressing and pulling the movable bearing sleeve,

341-pressing and pulling the double-sided groove,

342-a convex body is pulled upwards,

343-vertically pressing down the bottom end bearing,

344 — vertically pull up the bottom end bearing;

350-electronic compass.

500-a strain control unit, the strain control unit,

510-a stepper motor; 520-motor drive; 530 — a motor controller; 540 — a carrier disc;

550-strain connection plate.

600-a water pressure loading unit, wherein,

610-confining pressure pore water pressure cylinder; 620-pore pressure water pressure cylinder; 630-confining pressure hole water adding cylinder;

640-a hole pressure hole water adding cylinder; 650-confining pressure hole pipe barrel; 660-hole pressing hole pipe barrel;

670-confining pressure hole piston rod; 680, pressing the hole piston rod; 690-base plate.

700-power source unit

710 — an air compressor;

7201. 7202-1 st, 2 nd four-way valve;

7203. 7204 three-way valves 1, 2;

7301. 7302, … … 7308-No. 1, 2 … … 8 pressure regulating valves;

7401. 7402 electromagnetic valves 1 and 2;

7501. 7502, 7503, 7504-1 st, 2 nd, 3 rd, 4 th electric proportional valve;

7601. 7602, 7603, 7604-1 st, 2 nd, 3 rd, 4 th signal generator;

7701. 7702 time relay 1, 2;

7801. 7802-1 st, 2 nd power supply.

800-consolidation stress ratio applying unit,

810-a pressure transmission bracket;

820-stress ratio connection plate;

830-the pressure-applying module(s),

831-pressure cylinder, 832-pressure sensor, 833-T-shaped iron ruler,

8341-1 st displacement meter, 8342-2 nd displacement meter.

900-torsional load applying unit

910-left connecting rod;

920-left half of torsional load

921 — left cylinder; 922-1 st left torsion pressure sensor; 9231-twist left 1 st displacement gauge;

9232-twist left 2 nd displacement gauge; 924-left twisting the T-shaped iron ruler; 925-left rack;

930-right connecting rod;

940-torsional load right half

941-right cylinder; 942 — 2 nd right torsion pressure sensor;

9431-twist right 3 rd displacement gauge; 9432-twist right 4 th displacement gauge;

944-right twisting the T-shaped iron rule; 945-right rack.

1000-data acquisition instrument.

1100-computer.

Detailed Description

The following detailed description is made with reference to the accompanying drawings and examples:

first, the structure of this system

1. General of

As shown in fig. 1 and 2, the system comprises a test object, namely a pile foundation unit 000;

the device is provided with a support 100, a pile foundation pressure chamber unit 200, a dynamic and static load applying unit 300, a strain control unit 500, a water pressure loading unit 600, a power source unit 700, a soil consolidation stress ratio applying unit 800, a torsional load applying unit 900, a data acquisition instrument 1000 and a computer 1100;

the position and connection relation is as follows:

the bracket 100 is provided with upper, middle and lower return brackets 111, 112 and 113;

a dynamic and static load applying unit 300, a hammering load applying unit 400 and a torsion load applying unit 900 are respectively arranged below the upward-downward type bracket 111;

a pile foundation pressure chamber unit 200 is arranged on the middle-back type support 112, and a pile foundation unit 000 is arranged in the pile foundation pressure chamber unit 200;

a strain control unit 500 and a soil consolidation stress ratio application unit 800 are arranged below the middle-back type support 112;

a water pressure loading unit 600 is arranged on the lower returning bracket 113;

the power source unit 700 arranged outside the bracket 100 is respectively communicated with the dynamic and static load applying unit 300, the water pressure loading unit 600, the soil consolidation stress ratio applying unit 800 and the torsional load applying unit 900 through pipe barrels to provide power;

the water pressure loading unit 600 is communicated with the pile foundation pressure chamber unit 200 through a pipe barrel to provide pore water pressure and soil body external confining pressure;

the dynamic and static load applying unit 300, the strain control unit 500, the soil consolidation stress ratio applying unit 800 and the torsional load applying unit 900 are respectively connected with the pile foundation pressure chamber unit 200 to provide various loads;

the support 100 is also externally provided with a data acquisition instrument 1000 and a computer 1100, and the pile foundation pressure chamber unit 200, the data acquisition instrument 1000 and the computer 1100 are sequentially connected to acquire test data.

The working mechanism is as follows:

the pile foundation unit 000 is a detection object of the system, and mainly comprises calcareous sand (pile foundation consisting of model piles) of marine island reefs in China;

the stent 100 is the support of the present system;

the pile foundation pressure chamber unit 200 is a test site of a pile foundation unit 000;

the water pressure loading unit 600 and the dynamic and static load applying unit 300 provide a basic working environment for water pressure loading and dynamic and static load application to the pile foundation unit 000;

the strain control unit 500, the soil consolidation stress ratio applying unit 800 and the torsional load applying unit 900 are special working environments for providing hammering load, strain control, soil consolidation stress ratio and torsional load application for the pile foundation unit 000 respectively, namely simulating the working environment of marine island reefs in China;

power source unit 700 is a power source that provides power to a load;

various sensors are provided in the pile foundation unit 000 to collect data, and the data is analyzed by the data collector 1000 and the computer 1100.

2. Functional unit

0) Pile foundation unit 000

As shown in fig. 3, the pile foundation unit 000 is a test object of the present system, and includes pile side soil 010, pile end soil 020, rubber membrane 030, soil sample cap 040, and model pile 050;

the soil sample cap 040, the pile side soil 010 and the pile end soil 020 are sequentially connected into a cylinder, the outer wall of the cylinder is wrapped with a rubber film 030, and the soil sample cap 040 and the pile side soil 010 are sequentially inserted into the lower portion of the model pile 050.

(1) Pile side soil 010

The side soil 010 is calcareous sandy soil with the soil particle size of 0.075-5mm and the relative compactness of 0.55;

(2) pile tip soil 020

The pile tip soil 020 is prepared by mixing cement, gypsum and calcareous sandy soil according to the weight ratio of 3: 2: 5, preparing the cemented calcareous sand;

(3) rubber film 030

The rubber film 030 is a common member.

(4) Soil sample cap 040

The soil sample cap 040 is an annular cap having a hole in the middle.

(5) Model pile 050

As shown in fig. 4 and 5, the model pile 050 comprises a model pile upper cap 051, a pin 052, a model pile left half part 0531, a model pile right half part 0532, a model pile lower cap 054, a soil pressure box 055, a strain gauge 056, a wire outlet hole 057, a level ruler 058, a potentiometer 059, a gear 0510 and a torsion fixing screw 0511;

the model pile 050 is an aluminum alloy cylinder, standard threads are lathed on the inner walls of two ends of the cylinder, and then the center of the cylinder is split in a wire cutting mode to form a model pile left half part 0531 and a model pile right half part 0532;

the model pile left half part 0531 and the model pile right half part 0532 are connected together through a pin 052 to form a fixed body;

the model pile upper cap 051 and the model pile lower cap 054 are respectively of a lower convex structure and an upper convex structure, are respectively positioned at the top and the bottom of the model pile 050 and are lathed with threads, and the combined model pile 050 is fixed through the threads;

the strain gauge 056 is stuck on the inner wall of the model pile left half 0531 and the model pile right half 0532, and the soil pressure box 055 is placed in the model pile lower cap 214;

the lead wire positioned at the end part of the strain gauge 056 is led out from a wire outlet hole 057 arranged on the left half part 0531 of the model pile and is connected with the data acquisition instrument 1000;

the soil pressure cell 055 adopts a bottom outlet mode, a lead is led out from a wire outlet hole in the center of a lower cap 054 of the model pile, passes through the upper part, is led out from a wire outlet hole 217 formed in the left half part 2131 of the model pile, and is connected with the data acquisition instrument 1100;

and a torsion fixing screw 0511 penetrates through a gear 0510 and one end of a level ruler 058 to be fixedly connected with the center of a model pile upper cap 051, the other end of the level ruler 058 is connected with a potentiometer 059, and the potentiometer 059 is fixed on the support 100 through a magnetic gauge stand.

The working principle is as follows: the strain gauge 056 is used for measuring the pile body strain of the model pile 050, the soil pressure box 055 is used for measuring the pressure change of pile end soil 020 at the lower cap 054 of the model pile, and the electric displacement meter 059 is used for measuring the vertical settlement at the upper cap 051 of the model pile.

1) Support 100

As shown in fig. 6, the bracket 100 includes a clip-shaped bracket 110, a lead screw 120, a support plate 130, and a slide 140;

the clip type bracket 110 includes an upper clip type bracket 111, a middle clip type bracket 112 and a lower clip type bracket 113;

the bracket 100 is connected with the support plate 130 through the clip bracket 110, the lead screw 120 to form a whole; the slide rail 140 is provided on the rising-falling type bracket 111.

The working principle is as follows: the upper-back type bracket 111, the middle-back type bracket 112 and the lower-back type bracket 113 are connected through the lead screw 120 and fixed by nuts to form a basic stable structure of the whole system, can bear the pressure required by the test and keep the stability of the whole system; the supporting plate 130 is provided with a hole so that the strain control unit 500 is not subjected to frictional damping by the clip bracket 110 when working, and the supporting plate 130 is provided with a groove so that the consolidation stress ratio applying unit 800 and the strain control unit 500 are switched; the purpose of chute 140 is to ensure the perpendicularity of the drop of ramming module 460 while reducing the frictional damping to which it is dropped.

2) Pile foundation pressure chamber unit 200

As shown in fig. 7, 8 and 9, the pile pressure chamber unit 200 includes an upper glass cover 220, a bottom plate 230 and a sealing member 240;

the upper glass cover 220 and the lower plate 230 are connected up and down to form a container in which the pile foundation unit 000 is installed, and the space between the model piles 050 and the upper glass cover 220 is sealed by a sealing member 240.

(1) Upper glass cover 220

As shown in fig. 8, 9 and 12, the upper glass cover 220 is a transparent glass cover, and is used for bearing confining pressure exerted by water between rubber membranes 030 in the pile foundation unit 000, so that confining pressure of external soil is simulated to be exerted on the pile foundation unit 000, and a closed environment is provided.

The upper glass cover 220 comprises an upper glass cover upper disc surface 221, a glass cylinder 222, an upper glass cover lower disc surface 223, a fixed screw rod 224 and a fixed nut 225;

the upper glass cover upper plate surface 221, the glass cylinder 222 and the upper glass cover lower plate surface 223 are integrated through a fixed screw rod 224 and a fixed nut 225.

(2) Chassis 230

As shown in fig. 10, the base plate 230 is a disk having a three-step shape, and is provided with a 1 st confining pressure hole 231, a2 nd confining pressure hole 232, a 1 st confining pressure hole 233, and a2 nd confining pressure hole 234.

The working principle is as follows: the water pressure loading unit 600 provides confining pressure required by the test through the 1 st confining pressure hole 231 (water inlet), the pile foundation unit 000 is located in the rubber film 030, the 2 nd confining pressure hole 232 serves as a water outlet, and confining pressure of the pile foundation unit 000 is simulated for the rubber film 030 through water pressure; the water outlet of the 1 st hole pressure hole 233 is used for providing water pressure for the pile foundation unit 000 through the bottom water pressure loading unit 600; the 2 nd hole pressure hole 234 functions as a water inlet.

(3) Seal 240

As shown in fig. 11 and 12, the sealing member 240 includes a convex sealing body 241, a 1 st sealing ring 242, a2 nd sealing ring 243, and a circular nut 244;

the convex sealing body 241 is connected with the upper disc surface 221 of the upper glass cover through a round nut 244, and a clip groove with a certain depth is lathed inside the convex sealing body 241 and is used for installing a 1 st sealing ring 242 and a2 nd sealing ring 243;

the 1 st and 2 nd seal rings 242 and 243 are common members that function as seals and lubricates and allow the soil sample cap 040 to slide therein.

3) Dynamic and static load applying unit 300

The dynamic and static load applying unit 300 includes a dynamic and static cylinder 310 and a dynamic and static dowel bar 320 connected up and down.

The moving and static air cylinder 310 is tightly connected with the upward-returning type bracket 111 of the bracket 100 through a nut; the movable end of the movable and static cylinder 310 is connected with a movable and static dowel bar 320.

The moving and static air cylinder 310 is a universal part and is of the type CDQ2KB25-30DM, and the working principle of the moving and static air cylinder is that a piston rod is arranged at one end, air is supplied from one side of the piston and is gathered to generate air pressure, the air pressure pushes the piston to generate thrust to extend out, and the thrust returns by virtue of a spring or self weight.

The lower part of the cylinder 320 is connected with a press-pull movable bearing sleeve 340;

the lower rod of the air cylinder 320 is provided with threads as shown in figure 13, figure 14 and figure 15, and is connected with the upper grooves of the press-pull double-sided grooves 341 through threads,

The 342 upward-pulling convex body sequentially passes through 344 the vertical upward-pulling bottom end bearing, the second pressing-pulling supporting clapboard 332, the vertical downward-pressing bottom end bearing 343 and 341 to be fixedly connected with the groove below the pressing-pulling double-sided groove, so as to form a whole.

As shown in fig. 14, the supporting partition 330 includes a first press-pull supporting partition 331, a second press-pull supporting partition 332, a third press-pull supporting partition 333, a press-pull vertical screw 334, and a press-pull locking nut 335;

the first pressing and pulling support partition 331, the second pressing and pulling support partition 332 and the third pressing and pulling support partition 333 are fixedly connected by a pressing and pulling vertical screw rod 334 and a pressing and pulling locking nut 335 to form a herringbone support partition 330;

the electronic compass 350 is located 332 on the second pressure-pull support spacer;

the torsion nut 0511 sequentially penetrates through the gear 0510 and the third pressing and pulling support partition plate 333 to be connected with an upper cap 051 of the model pile 050;

the vertical pull-up bottom end bearing 344 and the vertical push-down bottom end bearing 343 are universal parts, and are used for providing the middle of a contact surface which is relatively stressed, releasing the horizontal constraint of the contact surface and enabling the contact surface to freely and horizontally rotate;

(3) press-pull movable bearing set 340

As shown in fig. 15, the press-pull movable bearing kit 340 includes a press-pull double-sided groove 341, a pull-up protrusion 342, a vertical press-down bottom end bearing 343, and a vertical pull-up bottom end bearing 344;

the dynamic and static dowel bars 320 are connected with the pull-up convex body 342 through the double-sided groove 341;

the working principle is as follows:

3-214, the supporting partition 330 comprises a first press-pull supporting partition 331, a second press-pull supporting partition 332, a third press-pull supporting partition 333, a press-pull vertical screw 334, and a press-pull locking nut 335;

the supporting partition plates 330 are connected into a whole through a pressing and pulling vertical screw rod 334, first, second and third supporting partition plates 331, 332 and 333, and a pressing and pulling locking nut 335.

A complex body formed by the dynamic and static air cylinder 310, the dynamic and static dowel bar 320 and the vertical pressing bottom end bearing 343 is arranged on the first pressing and pulling support plate 331;

a pneumatic vibration hammer 350 is arranged on the second tension and compression support plate 332;

a model pile 050 is arranged below the third tension-compression support plate 333;

the air pressure of the power source unit 700 enters the dynamic and static air cylinders 310, the air pressure presses the dynamic and static dowel bars 320 downwards, the dowel bars stretch out when being pressed downwards, the vertical pressing bottom end bearing 343 applies the pressure on the second pressing and pulling support partition plate 332, the pressure is further transmitted to the model piles 050, and meanwhile, the vertical pressing bottom end bearing 343 cannot limit the model piles to twist.

The air pressure of the power source unit 700 enters the dynamic and static air cylinders 310, the air pressure pulls the static dowel bar 320 upwards, the dowel bar stretches out when being pressed downwards, the 344 vertical pull-up bottom end bearing applies pressure to the 1 st press-pull supporting partition plate 331, the force is further transmitted to the model pile 050 through the 3 rd press-pull supporting partition plate 331, and meanwhile, the 344 vertical pull-up bottom end bearing does not limit the torsion of the model pile.

The electronic compass 350 is positioned on the second pressure-pull supporting clapboard 332 and can record reading;

5) strain control unit 500

As shown in fig. 16, the strain control unit 500 includes a stepping motor 510, a motor driver 520, a motor controller 530, a carrier disc 540, and a strain connection plate 550;

the connection relation is as follows:

the motor controller 530, the motor driver 520, the stepping motor 510, the strain connecting plate 550 and the bearing disc 540 are connected in sequence;

the strain connection plate 550 is connected with the hollow bracket 112 of the bracket 100 by bolts and nuts.

(1) Stepping motor 510

The stepping motor 510 is a general-purpose part, and is an MLA20 linear stepping motor, which is an open-loop control element that converts an electrical pulse signal into a linear displacement; under the condition of non-overload, the rotating speed and the stopping position of the motor only depend on the frequency and the pulse number of the pulse signal and are not influenced by the load change, namely, a pulse signal is added to the stepping motor 510, and the stepping motor 510 rotates by a stepping angle; the existence of this linear relationship, coupled with the characteristic that the stepping motor 510 has only periodic error and no accumulated error, makes the control with the stepping motor in the control fields of speed, position, etc. very simple.

(2) Motor driver 520

The motor driver 520 is a universal component, is selected from 42BYG34-401, and is an actuating mechanism for converting electric pulse into angular displacement.

(3) Motor controller 530

The motor controller 530 is a universal component, and the model is selected to be DMA8600048, and the motor controller is used for sending out uniform electric pulse signals.

(4) Load bearing disk 540

The dummy pile pressure chamber unit 200 is connected to the bearing disk 540, and the strain rate can be controlled by controlling the rising rate of the bearing disk 540 and thus the rising rate of the dummy pile pressure chamber unit 200.

(5) Strain connection plate 550

The strain connection plate 550 is connected with the hollow bracket 112 of the bracket 100 by bolts and nuts.

Working principle of the strain control unit 500:

the strain control unit 500 is slid by moving the left and right positions of the strain connecting plate 550, the strain connecting plate 550 is connected with the middle-back type bracket 112 of the bracket 100 through bolts and nuts, and the bolts and nuts need to be screwed off when sliding is needed; the motor controller 530 controls the motor 510 by controlling the motor driver 520, and the motor 510 extends upward so as to control the rate of ascent of the carrier puck 540 and thus the rate of ascent of the model pile pressure chamber unit 200 to control the strain rate.

6) Water pressure loading unit 600

As shown in fig. 17, the water pressure loading unit 600 includes a confining pressure pore water pressure cylinder 610, a pore pressure pore water pressure cylinder 620, a confining pressure pore water adding cylinder 630, a pore pressure pore water adding cylinder 640, a confining pressure pore pipe barrel 650, a pore pressure pore pipe barrel 660, a confining pressure pore piston rod 670, a pore pressure pore piston rod 680 and a bottom plate 690;

the confining pressure pore water pressure cylinder 610, the confining pressure pore piston rod 670, the confining pressure pore water adding cylinder 630 and the confining pressure pore pipe barrel 650 are sequentially connected;

the pore pressure pore water pressure cylinder 620, the pore pressure pore piston rod 680, the pore pressure pore water adding cylinder 640 and the pore pressure pore pipe barrel 660 are sequentially connected;

the bottom plate 690 serves as a support body of the water pressure loading unit 600.

The water adding cylinder 630 and the pipe barrel 650 of the confining pressure hole are filled with water; the inside of the port-pressure-hole-watering cylinder 640 and the port-pressure-hole tube 660 are filled with water.

The confining pressure hole water pressure cylinder 610, the pore pressure hole water pressure cylinder 620, the confining pressure hole water adding cylinder 630 and the pore pressure hole water adding cylinder 640 are universal parts, the types of the confining pressure hole water pressure cylinder are CDQ2KB25-30DM, the working principle of the confining pressure hole water adding cylinder is that a piston rod is arranged at one end, air supply energy accumulation is carried out from one side of a piston to generate air pressure, and the air pressure pushes the piston to generate thrust to extend out and return by a spring or dead weight.

The working principle of the water pressure loading unit 600 is as follows:

as shown in fig. 18, when the confining pressure hole water pressure cylinder 610 moves to the right for exhausting, the confining pressure hole water adding cylinder 630 is driven to absorb water through the confining pressure hole piston rod 670, then the confining pressure hole water pressure cylinder 610 absorbs air to drive the confining pressure hole water adding cylinder 630 to push water, so that external pressure is applied to the outer surface of the rubber film 030 in the pile base unit 000 in the upper glass cover 220, and the pressure of the surrounding soil body received by the real soil body is simulated;

when the pore pressure pore water pressure cylinder 620 exhausts, the pore pressure pore water adding cylinder 640 is driven to absorb water through the pore pressure pore piston rod 680, then the pore pressure pore water pressure cylinder 620 inhales to drive the pore pressure pore water adding cylinder 640 to push water, and therefore internal pore water pressure is applied to the calcium sand in the rubber film 030 in the pile foundation unit 000.

The confining pressure hole water adding cylinder 630 and the hole pressure hole water adding cylinder 640 need to repeatedly absorb water and push water before water pressure is applied so as to discharge gas in the hole pressure hole water adding cylinder 640, the hole pressure hole pipe barrel 660, the confining pressure hole water adding cylinder 630 and the confining pressure hole pipe barrel 650.

6) Power source unit 700

As shown in fig. 19 and 20, the power source unit 700 includes an air compressor 710, 1 st and 2 nd four- way valves 7201 and 7202, 1 st and 2 nd three- way valves 7203 and 7204, 1 st and 2 nd 2 … … 8 th pressure regulating valves 7301, 7302 and … … 7308, 1 st and 2 nd electromagnetic valves 7401 and 7402, 1 st, 2 nd, 3 nd and 4 th electric proportional valves 7501, 7502, 7503 th and 7504, 1 st, 2 nd, 3 th and 4 th signal generators 7601, 7602, 7603 and 7604, 1 st and 2 nd time relays 7701 and 7702, and 1 st and 2 nd power supplies 7801 and 7802; connected by a tube.

The parts are all universal parts.

The air compressor 710 is 800Wx4-620L in model number, and is mainly used for providing compressed air with certain pressure, and the peak value of the output air pressure range is usually 0-0.7 Mpa; an air compressor outlet is provided on the air compressor 710.

The type of the pressure regulating valve is AR2000-02, the pressure regulating valve is mainly used for regulating the output gas pressure value of the air compressor, the pressure regulating valve is provided with a pressure regulating valve air inlet and a pressure regulating valve air outlet, and the pressure regulating valve air inlet is connected with the air compressor air outlet.

The electromagnetic valve is N4V210-08 in model and is provided with an air inlet and an air outlet, and the air outlet of the electromagnetic valve is connected with the air inlet of the air cylinder and is used for controlling the on-off of air flow.

The time relay is of a type of a quality ohm dragon H3Y-2 or a time relay H3Y-2-C AC220H3Y-4 and a DC24V12V8, and is mainly used for realizing power on and power off through parameters set manually and controlling the time of the power on and power off.

The signal generator is in the model of SIN-C702, and is used for outputting a voltage signal which changes along with the waveform according to artificial parameter setting, for example, the function signal generator 760 used in the invention can output voltage signals with different waveforms such as sine waveform, linear waveform and sawtooth waveform.

Working principle of power source unit 700:

the pressure generated by the air compressor 710 flows to the 1 st and 2 nd four- way valves 7201 and 7202 and the 1 st and 2 nd three- way valves 7203 and 7204 through pipe cylinders, and then the output pressure is controlled by the 1 st and 2 nd 2 … … 8 th pressure regulating valves 7301, 7302 and … … 7308; the output and interruption of the pressure of the air flow flowing to the control part by the 1 st and 2 nd electromagnetic valves 7401 and 7402; the time of power-on and power-off is controlled by the 1 st and 2 nd time relays 7701 and 7702. The required pressure is provided to the experimental cylinder through the above functional components.

8) Consolidation stress ratio applying unit 800 (pull-up load unit 800)

As in fig. 21, consolidation stress ratio application unit 800 includes a pressure transfer bracket 810, a stress ratio connection plate 820, and a pressure application module 830;

the position and connection relation is as follows:

the pressure transmission bracket 810 is provided with a groove connected with the pressure applying module 830, and a stress ratio connecting plate 820 is arranged above the pressure applying module 830; the stress ratio connecting plate 820 is connected with the hollow bracket 112 through bolts and nuts.

(1) Pressure transmission bracket 810

As shown in fig. 21 and 12, the pressure transmission bracket 810 is rectangular, and a hole slightly larger than the diameter of the model pile 050 and slightly smaller than the diameter of the soil sample cap 040 is formed in the middle of the pressure transmission bracket 810 and connected with the soil sample cap 040;

(2) stress ratio connecting plate 820

The stress ratio connection plate 820 is a rectangular plate.

(3) Pressure application module 830

As shown in fig. 22, the pressure application module 830 includes an air cylinder 831, a pressure sensor 832, a T-shaped iron rule 833 and 1 st and 2 nd displacement meters 8341 and 8342;

the position and connection relation is as follows:

the cylinder 831, the pressure sensor 832 and the T-shaped iron rule 833 are connected in sequence, and the 1 st and 2 nd displacement meters 8341 and 8342 are respectively arranged at both ends of the T-shaped iron rule 833.

The operation principle of the consolidation stress ratio applying unit 800:

the power source unit 700 provides air pressure adjusted by a 5 th pressure adjusting valve 7305 to the air cylinder 831, so that the air cylinder 831 extends downwards and applies pressure to the pressure transmission bracket 810, and the pressure is transmitted to the model pile 050 through the pressure transmission bracket 810; sliding the position of the consolidation stress ratio applying unit 800 by moving the left and right positions of the stress ratio connecting plate 820, connecting the stress ratio connecting plate 820 and the middle-back type bracket 112 of the bracket 100 through bolts and nuts, and moving to a proper position and screwing the nuts when the consolidation stress ratio is required to be applied; the pressure sensor 832, the 1 st displacement meter 8341 and the 2 nd displacement meter 8342 are connected with the computer 1200, so that pressure and displacement data at various moments can be collected.

As in fig. 21, consolidation stress ratio application unit 800 includes a pressure transfer bracket 810, a stress ratio connection plate 820, and a pressure application module 830;

the position and connection relation is as follows:

the pressure transmission bracket 810 is provided with a groove connected with the pressure applying module 830, and a stress ratio connecting plate 820 is arranged above the pressure applying module 830; the stress ratio connecting plate 820 is connected with the hollow bracket 112 through bolts and nuts.

(1) Pressure transmission bracket 810

As shown in fig. 21 and 12, the pressure transmission bracket 810 is rectangular, and a hole slightly larger than the diameter of the model pile 050 and slightly smaller than the diameter of the soil sample cap 040 is formed in the middle of the pressure transmission bracket 810 and connected with the soil sample cap 040;

(2) stress ratio connecting plate 820

The stress ratio connection plate 820 is a rectangular plate.

(3) Pressure application module 830

As shown in fig. 22, the pressure application module 830 includes an air cylinder 831, a pressure sensor 832, a T-shaped iron rule 833 and 1 st and 2 nd displacement meters 8341 and 8342;

the position and connection relation is as follows:

the cylinder 831, the pressure sensor 832 and the T-shaped iron rule 833 are connected in sequence, and the 1 st and 2 nd displacement meters 8341 and 8342 are respectively arranged at both ends of the T-shaped iron rule 833.

The operation principle of the consolidation stress ratio applying unit 800:

the power source unit 700 provides the air pressure adjusted by the 5 th pressure adjusting valve 7305 to the air cylinder 831, so that the air cylinder 831 extends downwards to apply the pressure to the pressure transmission bracket 810, and the pressure is transmitted to the model pile 050 through the pressure transmission bracket 810; sliding the position of the consolidation stress ratio applying unit 800 by moving the left and right positions of the stress ratio connecting plate 820, connecting the stress ratio connecting plate 820 and the middle-back type bracket 112 of the bracket 100 through bolts and nuts, and moving to a proper position and screwing the nuts when the consolidation stress ratio is required to be applied; the pressure sensor 832, the 1 st displacement meter 8341 and the 2 nd displacement meter 8342 are connected with the computer 1200, so that pressure and displacement data at various moments can be collected.

9) Torsional load application unit 900

As shown in fig. 24, 25 and 11, the torsional load applying unit 900 includes a left connecting rod 910, a torsional load left half 920, a torsional load right half 930, a right connecting rod 940,

the left torsional load half part 920 and the right torsional load half part 930 are respectively arranged on two sides of the pile foundation pressure chamber unit 200; is connected with the upper-returning bracket 111 through a left connecting rod 910 and a right connecting rod 930 arranged at the upper part of the upper-returning bracket; the gear 0510 is connected with a model pile upper cap 051 of the model pile 050 through a torsion fixing screw 0511;

as shown in fig. 26, the left half torsional load part 920 is formed by sequentially connecting a left air cylinder 921, a 1 st left torsional pressure sensor 922, a left torsional T-shaped iron ruler 924 and a left rack 925, wherein a torsional left 1 st displacement meter 9231 and a torsional left 2 nd displacement meter 9232 are respectively arranged at two ends of the left torsional T-shaped iron ruler 924;

as shown in fig. 27, the right torsional load half 940 includes a right cylinder 941, a2 nd right torsional pressure sensor 942, a right torsional T-shaped iron rule 944 and a right rack 945 connected in sequence, and a right torsional 3 rd displacement gauge 9431 and a right torsional 4 th displacement gauge 9432 are respectively disposed at both ends of the right torsional T-shaped iron rule 944.

The operating principle of the torsional load applying unit 900 is:

the power unit 700 provides air pressure regulated by a 3 rd pressure regulating valve 7303 and a 4 th pressure regulating valve 7304 to the left air cylinder 921 and the right air cylinder 941 to enable the left rack 925 and the right rack 945 to move so as to drive the gear 0510 to move and further apply torsional load to the model pile 050; test data was collected by the 1 st left torsional pressure sensor 922, the torsional left 1 st displacement gauge 9231, the torsional left 2 nd displacement gauge 9232, the 2 nd right torsional pressure sensor 942, the torsional right 3 rd displacement gauge 9431 and the torsional right 4 th displacement gauge 9432.

Second, testing method of the system

1. Loading

1) Static load loading

Firstly, pile side soil 010 is configured according to the requirement of a test scheme, the pile side soil 010 is wrapped by a rubber film 030, the lower part of the rubber film 030 is sealed with the base of the chassis 230 by vaseline, and the upper part of the rubber film 030 is sealed with the model pile 050 by vaseline;

disassembling the model pile 050 and attaching strain gauges 056 to the left half part 0531 and the right half part 0532 of the model pile;

thirdly, connecting all units of the system according to the drawing without connecting a tamping module 460; removing the strain control unit 500 and moving the consolidation stress ratio application unit 800 to just below the pile pressure chamber unit 200;

fourthly, the pile foundation pressure chamber unit 200 is filled with water, the air in the pipe barrel 640 is emptied by using the air exhaust operation, and the 1 st pressure regulating valve 7301, the 2 nd pressure regulating valve 7302, the 5 th pressure regulating valve 7305, the 6 th pressure regulating valve 7306 and the 7 th pressure regulating valve 7307 are regulated according to the experiment requirements to control the output pressure;

opening the air compressor 510;

sixthly, controlling solenoid valves 7401, 7402, 7403, 7404 and 7405 of No. 1, No. 2, No. 3, No. 4 and No. 5 according to experimental requirements to control the on-off of air flow;

seventhly, after the test is finished, if no special requirement exists, the 1 st, 2 nd, 5 th, 6 th and 7 th pressure regulating valves 7301, 7302, 7305, 7306 and 7307 are firstly regulated to 0, the air compressor 710 is closed, water in the pile foundation pressure chamber unit 200 is put in, the pile foundation unit 000 is taken out, and the rubber film 030 is dried.

2) Dynamic load loading

Firstly, pile side soil 010 is configured according to the requirement of a test scheme, the pile side soil 010 is wrapped by a rubber film 030, the lower part of the rubber film 030 is sealed with the base of the chassis 230 by vaseline, and the upper part of the rubber film 030 is sealed with the model pile 050 by vaseline;

disassembling the model pile 050 and attaching strain gauges 056 to the left half part 0531 and the right half part 0532 of the model pile;

filling the pile foundation pressure chamber unit 200 with water, evacuating air in the pipe barrel 640 by using an exhaust operation, and adjusting pressure regulating valves 7301, 7302, 7305, 7306, 7307 of No. 1, No. 2, No. 5, No. 6, No. 7 according to experimental requirements to control the output pressure;

fourthly, the air compressor 710 is opened;

controlling the 1 st, 2 nd, 3 th, 4 th and 5 th electromagnetic valves 7401, 7402, 7403 th, 7404 th and 7405 th according to the experimental requirements to control the on-off of the airflow;

sixthly, after the test is finished, if no special requirement exists, the 1 st, 2 nd, 5 th, 6 th and 7 th pressure regulating valves 7301 and 7302 and the valves 7305, 7306 and 7307 are firstly adjusted to 0, the air compressor 710 is closed, water in the pile foundation pressure chamber unit 200 is placed, the pile foundation unit 000 is taken out, and the rubber film 030 is dried.

3) Strain loading

Firstly, pile side soil 010 is configured according to the requirement of a test scheme, the pile side soil 010 is wrapped by a rubber film, the lower part of a rubber sheet 030 is sealed with a base of a chassis 230 by Vaseline, and the upper part of the rubber film 030 is sealed with a model pile 050 by Vaseline;

the model pile 050 is disassembled, and strain gages 056 are attached to the left half portion 0531 and the right half portion 0532 of the model pile;

connecting the units of the system according to a diagram, removing the consolidation stress ratio applying unit 800 without connecting the tamping module 460, moving the strain control unit 500 to the position right below the pile foundation pressure chamber unit 200, and inputting parameters for controlling a strain path required by the test into the motor controller 530;

fourthly, the pile foundation pressure chamber unit 200 is filled with water, and the air of the pipe barrel 640 is emptied by using the air exhaust operation; adjusting the 1 st, 2 nd, 5 th, 6 th and 7 th pressure regulating valves 7301, 7302 th, 57305 th, 7306 th and 7307 th according to the experiment requirements to control the output pressure;

opening the air compressor 710;

sixthly, controlling solenoid valves 7401, 7402, 7403, 7404 and 7405 of No. 1, No. 2, No. 3, No. 4 and No. 5 according to experimental requirements to control the on-off of air flow;

seventhly, after the test is finished, if no special requirement exists, adjusting pressure regulating valves 7301, 7302, 7305, 7306, 7307 of 1 st, 2 nd, 5 th, 6 th, 7 th to 0, closing the air compressor 710, putting water in the model pile pressure chamber 200, taking out the pile foundation unit 000, and drying the rubber film 030.

4) Torsional loading

Firstly, pile side soil 010 is configured according to the requirement of a test scheme, the pile side soil 010 is wrapped by a rubber film 030, the lower part of the rubber film 030 is sealed with the base of the chassis 230 by vaseline, and the upper part of the rubber film 030 is sealed with the model pile 050 by vaseline;

disassembling the model pile 050 and attaching strain gauges 056 to the left half part 0531 and the right half part 0532 of the model pile;

thirdly, connecting all units of the system according to the drawing without connecting a tamping module 460; removing the strain control unit 500 and moving the consolidation stress ratio application unit 800 to just below the pile pressure chamber unit 200; connecting a gear 0511 to the model pile 050;

filling the pile foundation pressure chamber unit 200 with water, evacuating the air in the pipe barrel 640 by using an exhaust operation, and adjusting the 1 st, 2 nd, 3 rd, 4 th, 5 th, 6 th and 7 th pressure regulating valves 7301, 7302 th, 7303 th, 7304 th, 7305 th, 7306 th and 7307 th according to experimental requirements to control the output pressure;

opening the air compressor 710;

sixthly, controlling solenoid valves 7401, 7402, 7403, 7404 and 7405 according to experimental requirements to control on-off of air flow, ensuring equal air pressure in the left air cylinder 921 and the right air cylinder 931 and enabling the model pile 050 to be subjected to torque; wherein the torque is determined by the equation:

M＝2PSr

wherein: p is air pressure, S is the cross-sectional area of the cylinder, and r is the diameter of the gear;

seventhly, after the test is finished, if no special requirement exists, adjusting pressure regulating valves 7301, 7302, 7303, 7304, 7305, 7306, 7307 of 1 st, 2 nd, 3 th, 4 th, 5 th, 6 th, 7 th to 0, turning off the air compressor 710, discharging water in the pile foundation pressure chamber unit 200, taking out the pile foundation unit 000, and drying the rubber film 030.

2. Detection of

As shown in fig. 28, the sensors to which the present system relates include an earth pressure cell 055, a strain gauge 056, an electric displacement meter 059, a 1 st left torsional pressure sensor 922, a torsional left 1 st displacement meter 9231, a torsional left 2 nd displacement meter 9232, a2 nd right torsional pressure sensor 942, a torsional right 3 rd displacement meter 9431, and a torsional right 4 th displacement meter 9432;

each sensor is a universal piece, the output end of each sensor is connected with the input end of the data acquisition instrument 1000, and the output end of the data acquisition instrument 1000 is connected with the input port of the computer 1100.

The computer 1100 obtains the vertical displacement of the potentiometer 059 through the data acquisition instrument 1000, so as to obtain the vertical settlement at the position of the cap 051 on the measured model pile in the test.

The computer 1100 acquires the stress data of the soil pressure box 055 through the data acquisition instrument 1000, so as to acquire the pressure change of the pile end soil 020 at the lower cap 054 of the model pile;

the computer 1100 acquires stress data of the strain gauge 056 through the data acquisition instrument 1000, so as to acquire pile body strain of the model pile 050;

the computer 1100 obtains the torsion left 1 st displacement meter 9231, the torsion left 2 nd displacement meter 9232, the 2 nd right torsion pressure sensor 942, the torsion right 3 rd displacement meter 9431 and the torsion right 4 th displacement meter 9432 through the data acquisition instrument 1000, so as to obtain the torsion force and the torsion displacement of the model pile 050 under the action of the torsion load in the test.

The data acquisition instrument 1000 is a general-purpose component, and is generally a dynamic and static strain data acquisition instrument.

The computer 1100 is a common component.

Claims (1)

1. The utility model provides a calcareous sand pile foundation model test system that can simulate stormy waves twisting action which characterized in that:

comprises a test object, namely a pile foundation unit (000);

the device is provided with a support (100), a pile foundation pressure chamber unit (200), a dynamic and static load applying unit (300), a strain control unit (500), a water pressure loading unit (600), a power source unit (700), a soil consolidation stress ratio applying unit (800), a torsional load applying unit (900), a data acquisition instrument (1000) and a computer (1100);

the bracket (100) is provided with upper, middle and lower return brackets (111), (112) and (113);

a dynamic and static load applying unit (300) and a torsional load applying unit (900) are respectively arranged below the upper-back type bracket (111);

a pile foundation pressure chamber unit (200) is arranged on the middle-back type support (112), and a pile foundation unit (000) is arranged in the pile foundation pressure chamber unit (200);

a strain control unit (500) and a soil consolidation stress ratio application unit (800) are arranged below the middle-back type support (112);

a water pressure loading unit (600) is arranged on the lower-returning bracket (113);

the power source unit (700) arranged outside the bracket (100) is respectively communicated with the dynamic and static load applying unit (300), the water pressure loading unit (600), the soil consolidation stress ratio applying unit (800) and the torsional load applying unit (900) through the pipe barrel;

the water pressure loading unit (600) is communicated with the pile foundation pressure chamber unit (200) through the pipe barrel;

the movable units of the dynamic and static load applying unit (300), the strain control unit (500), the soil consolidation stress ratio applying unit (800) and the torsional load applying unit (900) are respectively connected with the pile foundation pressure chamber unit (200);

a data acquisition instrument (1000) and a computer (1100) are further arranged outside the support (100), and the pile foundation pressure chamber unit (200), the data acquisition instrument (1000) and the computer (1100) are sequentially connected;

the pile foundation unit (000) comprises a model pile (050), the model pile (050) is an aluminum alloy cylinder, standard threads are lathed on the inner walls of two ends of the cylinder, and then the center of the cylinder is split in a linear cutting mode to form a model pile left half part (0531) and a model pile right half part (0532);

the model pile left half part (0531) and the model pile right half part (0532) are connected together through a pin (052) to form a fixed body;

the model pile upper cap (051) and the model pile lower cap (054) are respectively of a lower convex structure and an upper convex structure, are respectively positioned at the top and the bottom of the model pile (050), are turned with threads, and the combined model pile (050) is fixed through the threads;

the strain gauge (056) is stuck on the inner wall of the left half part (0531) and the right half part (0532) of the model pile, and the soil pressure box (055) is arranged in the lower cap (054) of the model pile;

a lead positioned at the end part of the strain gauge (056) is led out from a wire outlet hole (057) arranged on the left half part (0531) of the model pile and is connected with a data acquisition instrument (1000);

the soil pressure cell (055) adopts a bottom outlet mode, a lead is led out from a wire outlet hole in the center of a lower cap (054) of the model pile, passes through the upper part, is led out from a wire outlet hole (057) formed in the left half part (0531) of the model pile, and is connected with the data acquisition instrument (1000);

a torsion fixing screw (0511) penetrates through a gear (0510) and one end of a level ruler (058) to be fixedly connected with the center of a model pile upper cap (051), the other end of the level ruler (058) is connected with a potential displacement meter (059), and the potential displacement meter (059) is fixed on a support (100) through a magnetic meter seat;

the water pressure loading unit (600) comprises a confining pressure hole water pressure cylinder (610), a hole confining pressure hole water pressure cylinder (620), a confining pressure hole water adding cylinder (630), a hole confining pressure hole water adding cylinder (640), a confining pressure hole pipe barrel (650), a hole confining pressure hole pipe barrel (660), a confining pressure hole piston rod (670), a hole confining pressure hole piston rod (680) and a bottom plate (690);

the confining pressure hole water pressure cylinder (610), the confining pressure hole piston rod (670), the confining pressure hole water adding cylinder (630) and the confining pressure hole pipe barrel (650) are sequentially connected;

the pore pressure pore water pressure cylinder (620), the pore pressure pore piston rod (680), the pore pressure pore water adding cylinder (640) and the pore pressure pore pipe barrel (660) are sequentially connected;

the bottom plate (690) serves as a support body of the water pressure loading unit (600);

the torsion load applying unit (900) comprises a left connecting rod (910), a torsion load left half part (920), a torsion load right half part (940) and a right connecting rod (930);

the left torsional load half part (920) and the right torsional load half part (940) are respectively arranged on two sides of the pile foundation pressure chamber unit (200); is connected with the upper-back type bracket (111) through a left connecting rod (910) and a right connecting rod (930) arranged at the upper part of the upper-back type bracket; the gear (0510) is connected with an upper cap (051) of the model pile (050) through a torsional fixing screw (0511);

the left half part (920) of the torsional load is formed by sequentially connecting a left air cylinder (921), a 1 st left torsional pressure sensor (922), a left torsional T-shaped iron ruler (924) and a left rack (925), and a torsional left 1 st displacement meter (9231) and a torsional left 2 nd displacement meter (9232) are respectively arranged at two ends of the left torsional T-shaped iron ruler (924);

the right torsional load half part (940) is formed by sequentially connecting a right cylinder (941), a2 nd right torsional pressure sensor (942), a right torsional T-shaped iron ruler (944) and a right rack (945), and a torsional right 3 rd displacement meter (9431) and a torsional right 4 th displacement meter (9432) are respectively arranged at two ends of the right torsional T-shaped iron ruler (944).

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