1. A pile sinking model test device is characterized by comprising an assembled model box, a test soil body which is filled into the model box and is provided with a layer of color mark layer at intervals of certain depth, a load applying device which is used for applying pressure to the model pile and enabling the model pile to sink into the test soil body, and a monitoring system which is used for monitoring the model pile and the test soil body, wherein the model box comprises:

a first half model chamber in a U shape;

the U-shaped opening side of the second half model chamber is detachably butted with the U-shaped opening side of the first half model chamber;

the transparent baffle is detachably blocked on the U-shaped opening side of the first half model chamber;

and the movable bracket comprises a cross beam which spans above the first half model chamber and is parallel to the transparent baffle, and a horizontal moving device connected with the load applying device is arranged on the cross beam in a sliding mode along the length direction.

2. The pile sinking model test apparatus of claim 1, wherein the bottom end of the first half model chamber is blocked by a bottom plate and a drain valve is provided at the bottom of the first half model chamber.

3. The pile sinking model test apparatus of claim 1, wherein the first and second half model chambers are each formed by axially splicing a plurality of model chamber modules.

4. The pile sinking model test device of claim 1, wherein the outer wall hoop of the first half model chamber is provided with a first U-shaped hoop, the outer wall hoop of the second half model chamber is provided with a second U-shaped hoop corresponding to the position of the first U-shaped hoop, and the opening side of the first U-shaped hoop and the opening side of the second U-shaped hoop are oppositely and outwards formed into connecting lugs for butt joint.

5. The pile sinking model test apparatus of claim 1, wherein said movable support comprises two steel supports fixed relatively to the outer wall of said first half-model chamber, the tops of said two steel supports extending out of said first half-model chamber, and the two ends of said cross beam are fixed to the tops of said two steel supports, respectively.

6. The pile sinking model test apparatus of claim 1, wherein the opposite inner walls of the U-shaped opening side of the first half model chamber are provided with grooves into which the transparent baffles are inserted.

7. A pile sinking model test method is characterized by comprising the following steps:

the assembling model box is used for assembling a U-shaped first half model chamber, and a transparent baffle is sealed at the U-shaped opening side of the first half model chamber;

filling a test soil body in the model box, and arranging a layer of color mark layer at certain intervals;

installing a movable bracket, wherein a cross beam is arranged above the first half model chamber in a crossing manner, a horizontal moving device is arranged on the cross beam in a sliding manner along the length direction, and a load applying device is connected to the horizontal moving device;

and sinking the pile, providing a model pile, applying external load to the pile top of the model pile by using the load applying device to enable the model pile to be sunk into the test soil body, and monitoring the model pile and the test soil body by using a monitoring system in the pile sinking process.

8. A pile sinking model test method is characterized by comprising the following steps:

the assembling model box is used for assembling a U-shaped first half model chamber and a U-shaped second half model chamber, and the U-shaped opening side of the second half model chamber is in butt joint connection with the U-shaped opening side of the first half model chamber;

filling a test soil body in the model box;

installing a movable bracket, wherein a cross beam is arranged above the first half model chamber in a crossing manner, a horizontal moving device is arranged on the cross beam in a sliding manner along the length direction, and a load applying device is connected to the horizontal moving device;

and sinking the pile, providing a model pile, applying external load to the pile top of the model pile by using the load applying device to enable the model pile to be sunk into the test soil body, and monitoring the model pile and the test soil body by using a monitoring system in the pile sinking process.

9. The pile sinking model test method of claim 7 or 8, wherein:

a bottom plate is blocked at the bottom end of the first half model chamber, and a drainage valve is arranged at the bottom of the first half model chamber;

after filling the test soil body and before pile sinking, performing saturation treatment on the test soil body, opening the drainage valve to inject water into the model box under pressure, so that the water body moves from bottom to top of the test soil body until the water body overflows the surface of the test soil body, closing the drainage valve, and standing for a period of time.

10. The pile sinking model test method of claim 8, wherein:

the first half model chamber and the second half model chamber are formed by splicing a plurality of model chamber modules along the axial direction;

and after pile sinking is finished, the model boxes are disassembled layer by layer, and soil around the piles is sampled.

Background

The problem of soft soil foundation can be met in engineering construction of high-rise buildings, large-span bridges, harbor high-pile wharfs, offshore wind turbines and the like, and the problem of how to meet the bearing capacity requirement of buildings (structures) needs to be met. The pile foundation is a foundation form widely adopted in coastal areas, and is widely used for providing vertical bearing capacity for a building foundation with large upper structure scale and weak surface layer and middle layer foundations or an underwater building foundation and providing horizontal bearing capacity for a building bearing horizontal forces such as seismic force, wave force, soil pressure and the like.

In the pile sinking construction process, the continuous injection process of the pile has obvious influence on soil around the pile, and mainly shows soil structure damage, soil deformation and excess pore water pressure response, so that the surrounding environment state of the pile is changed, and the self injection resistance and the bearing capacity aging of the pile foundation are influenced. In addition, when pile group construction is carried out, interaction exists between adjacent pile bodies, and the displacement of soil bodies between piles and the excess pore water pressure have a superposition effect. Therefore, it is necessary to deeply study the deformation and the excess pore water pressure response of the soil body near the continuous penetration stage of the pile body and the consolidation effect of the soil body after the penetration is finished.

At present, the research on pile sinking mainly includes: experimental study, theoretical study, numerical study, and the like. The field test in the experimental research is more in line with the actual situation, but has the defects of high cost, complex field environment, larger test result randomness, poor repeatability and the like. Compared with field tests, the indoor model test has the advantages of controllable test site environment, relatively low cost, repeatability, high test efficiency and the like, and is an effective method for deeply researching the continuous penetration mechanism of the pile body.

However, most of the model boxes adopted in the indoor model test are integral, and only aiming at a certain specific test environment, a single pile sinking mode (such as static pressure, hammering or vibration) and fixed pile body quantity, the model boxes cannot be disassembled and assembled according to test contents and can only be manufactured again, so that the test efficiency is reduced, and meanwhile, the cost control is not facilitated. In addition, because the integral model box can not be disassembled, the soil body around the pile is difficult to sample after the pile sinking model test is finished, and the conventional sampling mode can cause soil sample disturbance and influence the test result.

Disclosure of Invention

In order to solve the problems, the invention provides a pile sinking model test device and a test method.

The invention is realized by the following scheme: a pile sinking model test device comprises an assembled model box, a test soil body which is filled into the model box and is provided with a layer of color mark layers at intervals of certain depth, a load applying device which is used for applying pressure to a model pile and enabling the model pile to sink into the test soil body, and a monitoring system which is used for monitoring the model pile and the test soil body, wherein the model box comprises:

a first half model chamber in a U shape;

the U-shaped opening side of the second half model chamber is detachably butted with the U-shaped opening side of the first half model chamber;

the transparent baffle is detachably blocked on the U-shaped opening side of the first half model chamber;

and the movable bracket comprises a cross beam which spans above the first half model chamber and is parallel to the transparent baffle, and a horizontal moving device connected with the load applying device is arranged on the cross beam in a sliding mode along the length direction.

The pile sinking model test device is further improved in that a bottom plate is sealed at the bottom end of the first half model chamber, and a drainage valve is arranged at the bottom of the first half model chamber.

The pile sinking model test device is further improved in that the first half model chamber and the second half model chamber are formed by splicing a plurality of model chamber modules in the axial direction.

The pile sinking model test device is further improved in that a first U-shaped hoop is hooped on the outer wall of the first half model chamber, a second U-shaped hoop is hooped on the outer wall of the second half model chamber at a position corresponding to the first U-shaped hoop, and the opening side of the first U-shaped hoop and the opening side of the second U-shaped hoop form connecting lugs for butt joint oppositely and outwards.

The pile sinking model test device is further improved in that the movable support comprises two steel supports which are relatively fixed on the outer wall of the first half model chamber, the tops of the two steel supports extend out of the first half model chamber, and two ends of the cross beam are respectively fixed on the tops of the two steel supports.

The pile sinking model test device is further improved in that a groove for inserting the transparent baffle is formed in the opposite inner wall of the U-shaped opening side of the first half model chamber.

The invention also provides a pile sinking model test method, which comprises the following steps:

the assembling model box is used for assembling a U-shaped first half model chamber, and a transparent baffle is sealed at the U-shaped opening side of the first half model chamber;

filling a test soil body in the model box, and arranging a layer of color mark layer at certain intervals;

installing a movable bracket, wherein a cross beam is arranged above the first half model chamber in a crossing manner, a horizontal moving device is arranged on the cross beam in a sliding manner along the length direction, and a load applying device is connected to the horizontal moving device;

and sinking the pile, providing a model pile, applying external load to the pile top of the model pile by using the load applying device to enable the model pile to be sunk into the test soil body, and monitoring the model pile and the test soil body by using a monitoring system in the pile sinking process.

The invention also provides another pile sinking model test method, which comprises the following steps:

the assembling model box is used for assembling a U-shaped first half model chamber and a U-shaped second half model chamber, and the U-shaped opening side of the second half model chamber is in butt joint connection with the U-shaped opening side of the first half model chamber;

filling a test soil body in the model box;

installing a movable bracket, wherein a cross beam is arranged above the first half model chamber in a crossing manner, a horizontal moving device is arranged on the cross beam in a sliding manner along the length direction, and a load applying device is connected to the horizontal moving device;

and sinking the pile, providing a model pile, applying external load to the pile top of the model pile by using the load applying device to enable the model pile to be sunk into the test soil body, and monitoring the model pile and the test soil body by using a monitoring system in the pile sinking process.

The pile sinking model test method of the invention is further improved in that:

a bottom plate is blocked at the bottom end of the first half model chamber, and a drainage valve is arranged at the bottom of the first half model chamber;

after filling the test soil body and before pile sinking, performing saturation treatment on the test soil body, opening the drainage valve to inject water into the model box under pressure, so that the water body moves from bottom to top of the test soil body until the water body overflows the surface of the test soil body, closing the drainage valve, and standing for a period of time.

The pile sinking model test method of the invention is further improved in that:

the first half model chamber and the second half model chamber are formed by splicing a plurality of model chamber modules along the axial direction;

and after pile sinking is finished, the model boxes are disassembled layer by layer, and soil around the piles is sampled.

The present invention includes but is not limited to the following benefits:

1. through the setting of first half model room, second half model room, transparent baffle and mobile device for this mold box can be dismantled, the equipment in a flexible way, can carry out pile sinking half model tests such as static pressure, hammering and vibration or full model test, can carry out the experimental data monitoring of single pile or many piles, possesses visual characteristics, can more audio-visually observe the displacement change of the experimental soil body of pile sinking in-process, and the size of mold box is adjustable, and application scope is wide.

2. The splicing structure form of the multi-model chamber module of the first half model chamber and the second half model chamber makes the disassembly and assembly of the model box more flexible, and after the pile sinking model test is finished, the model box can be disassembled layer by layer, so that the soil around the pile can be conveniently sampled, and the study on the disturbance influence of the pile body injection on the adjacent soil is facilitated.

Drawings

FIG. 1 shows a schematic view of a model box structure of the present invention used in a semi-model test.

Fig. 2 shows a schematic view of a model box structure of the present invention used for full model test.

Figure 3 shows a schematic view of the first U-shaped band of the present invention.

Fig. 4 shows a schematic view of the installation of the monitoring system when performing a single pile sinking half model test using the present invention.

Fig. 5 shows a schematic view of the installation of the monitoring system when performing a double pile sinking semi-model test using the present invention.

Fig. 6 shows a layout of high-speed cameras when a semi-model test is performed by the pile sinking model test method of the present invention.

Detailed Description

The invention provides a pile sinking model test device and a test method, the pile sinking model test device can be flexibly disassembled and assembled, can be suitable for various different test contents, does not need to be manufactured again in each test, improves the test efficiency and saves the cost.

The pile sinking model test device and the test method are further described with specific embodiments in conjunction with the accompanying drawings.

Referring to fig. 1, 2 and 4, fig. 1 shows a schematic diagram of a model box structure when the invention is used for a half model test, fig. 2 shows a schematic diagram of a model box structure when the invention is used for a full model test, and fig. 4 shows a schematic diagram of an installation of a monitoring system when a single-pile driven pile half model test is carried out by using the invention.

A pile sinking model test device comprises an assembled model box 1, a test soil body 2 which is filled into the model box 1 and is provided with a layer of color mark layer 21 at intervals of certain depth, a load applying device 4 which is used for applying pressure to a model pile 3 and leading the model pile 3 to sink into the test soil body 2, and a monitoring system which is used for monitoring the model pile 3 and the test soil body 2, wherein the model box 1 comprises:

a first half model chamber 11 in a U shape;

a U-shaped second mold half chamber 12, the U-shaped opening side of the second mold half chamber 12 being detachably butted against the U-shaped opening side of the first mold half chamber 11;

a transparent baffle 13, wherein the transparent baffle 13 can be detachably blocked on the U-shaped opening side of the first half model chamber 11;

a movable bracket 14, wherein the movable bracket 14 comprises a beam 141 which crosses over the first half mould chamber 11 and is parallel to the transparent baffle 13, and a horizontal moving device 142 connected with the load applying device 4 is arranged on the beam 141 in a sliding way along the length direction.

Specifically, the transparent barrier 13 is tempered glass or a transparent organic glass plate. The first mold half 11 and the second mold half 12 may be made of organic glass. The opposite inner walls of the U-shaped opening side of the first mold half 11 are provided with grooves 113 into which the transparent barrier 13 is inserted. The movable support 14 includes two steel supports 143 fixed to the outer wall of the first half model chamber 11, the tops of the two steel supports 143 extend out of the first half model chamber 11, two ends of the cross beam 141 are fixed to the tops of the two steel supports 143, specifically, the steel supports 143 are U-channel steel frames, the cross beam 141 is an i-beam steel, a reaction frame is formed by the steel supports 143 and the cross beam 141, a guide rail for moving the pulley is installed on the cross beam 141, the horizontal moving device 142 is installed on the guide rail through the pulley, the load applying device 4 is fixed below the horizontal moving device 142, and the horizontal moving device 142 moves to enable the load applying device 4 to move along the cross beam 141 and apply pressure to the model pile 3 below the cross beam 141. Wherein the load applying means 4 is selected according to the test content, such as: when the static pressure pile needs to be simulated, a miniature hydraulic jack can be adopted; when a pile hammer needs to be simulated, a miniature hydraulic hammer is adopted; when the vibration pile needs to be simulated, a miniature vibration hammer can be adopted.

The model box 1 in the pile sinking model test device of the present invention is an assembled structure, which can be assembled into a first model box structure for half model test (as shown in fig. 1) or a second model box structure for full model test (as shown in fig. 2) according to the requirements of the test contents:

for the first mold box structure, it is only necessary to block the transparent baffle 13 on the U-shaped opening side of the first mold half 11, and the second mold half 12 is not necessary. The first model box structure is suitable for application occasions with relatively small test space requirements, and by adopting the first model box structure, the test situation in the box can be directly observed from the outside of the box through the transparent baffle 13, such as a single-pile sinking half-model test shown in fig. 4, and in the pile sinking process, the displacement change of the color mark layer 21 (namely the test soil body 2) can be observed more visually.

For the second type of model box structure, the second half model chamber 12 and the first half model chamber 11 need to be in butt joint connection, a transparent baffle 13 does not need to be blocked, and a model box with relatively large test space is formed by butt joint of the first half model chamber 11 and the second half model chamber 12.

The two types of model box structures can be flexibly selected according to the test requirements.

In a preferred embodiment, the bottom of the first mold half 11 is sealed with a bottom plate 111, and the bottom of the first mold half 11 is provided with a drain valve 112.

Specifically, the bottom plate 111 is made of organic glass, and water is injected into the model box 1 to perform saturation treatment on the test soil 2 during the pile sinking test through the arrangement of the bottom plate 111 and the drain valve 112. Of course, for the second model box structure, the second half model chamber 12 may also be provided with a bottom plate and a water discharge valve, when the first half model chamber 11 and the second half model chamber 12 are butted, two bottom plates should be butted simultaneously, and when the test soil is subjected to saturation treatment, two water discharge valves are used to fill water together, so as to accelerate the time of saturation treatment.

In a preferred embodiment, the first mold half 11 and the second mold half 12 are formed by axially splicing a plurality of mold half modules.

Particularly, concave-convex openings which are matched with each other are arranged between the adjacent model chamber modules (including between the adjacent model chamber modules of the first half model chamber 11, between the adjacent model chamber modules of the second half model chamber 12 and between the adjacent model chamber modules which are butted between the first half model chamber 11 and the second half model chamber 12), so that the splicing is facilitated, and meanwhile, the waterproof performance after the splicing is improved. In order to further improve the waterproof performance, a waterproof gasket can be additionally arranged between the adjacent model chamber modules. Through adopting above-mentioned mosaic structure form for this model box's dismantlement and equipment are more nimble, when the equipment, can dock this first half model room 11 and this second half model room 12 layer by layer earlier, splice from bottom to top in proper order along the axial of model box 1 again, after pile sinking model test, can dismantle this model box top-down layer by layer, are convenient for take a sample to the soil body of pile week, are favorable to studying the disturbance influence of pile body injection to the adjacent soil body.

As a preferred embodiment, referring to fig. 3, fig. 3 shows a schematic structural view of a first U-shaped hoop of the present invention. The outer wall of the first half-mould chamber 11 is hooped with a first U-shaped hoop 114, the outer wall of the second half-mould chamber 12 is hooped with a second U-shaped hoop 121 at a position corresponding to the first U-shaped hoop 114, and the opening side of the first U-shaped hoop 114 and the opening side of the second U-shaped hoop 121 are both relatively outward to form a connecting lug for butt joint.

Through the arrangement of the connecting lug, the first U-shaped hoop 114 can be fixed to the two steel supports 143 on the first half-model chamber 11, and can also be butted to the corresponding second U-shaped hoop 121, so that the two steel supports 143 are fixed more stably, and the first half-model chamber 11 is butted to the second half-model chamber 12 more tightly.

The invention also provides a pile sinking model test method, and by matching with the drawings of 4-6, the drawing of 4 shows the installation schematic diagram of the monitoring system when the invention is adopted to carry out the single-pile sinking half-model test, the drawing of 5 shows the installation schematic diagram of the monitoring system when the invention is adopted to carry out the double-pile sinking half-model test, and the drawing of 6 shows the layout diagram of the high-speed camera when the invention is adopted to carry out the half-model test. The method comprises the following steps:

step 11, assembling the model box 1, assembling a U-shaped first half model chamber 11, and blocking a transparent baffle 13 at the U-shaped opening side of the first half model chamber. A first mold box structure for a half-mold test was formed.

Step 12, filling the test soil 2 in the model box in layers, and arranging a layer of color mark layer 21 (dyeing fine sand can be adopted) at certain intervals. So that the displacement change of the colored sign layer 21 (i.e. the test soil body 2) can be visually observed through the transparent baffle 13 during the pile sinking process.

Step 13, installing the movable bracket 14, installing a beam 141 across above the first half mold chamber 11, installing a horizontal moving device 142 on the beam 141 in a sliding manner along the length direction, and connecting the load applying device 4 to the horizontal moving device 142.

And 14, sinking the pile to provide a model pile 3, applying external load to the top of the model pile 3 by using the load applying device 4 to enable the model pile 3 to sink into the test soil body 2, and monitoring the model pile 3 and the test soil body 2 by using a monitoring system in the pile sinking process.

Specifically, for the multi-pile sinking test, the pile sinking process for the plurality of model piles 3 is sequentially realized by moving the load applying device 4, and the plurality of model piles 3 will be arranged along the length direction of the cross beam 141. The monitoring system is configured according to the monitoring requirement, and in this embodiment, the monitoring system includes a plurality of sensors disposed on the model pile 3 and/or in the test soil 2, a collector 52 for collecting the sensing information of the plurality of sensors, and a computer 51 connected to the collector 52. Wherein, the multiple sensors include strain gauges attached to the model pile 3 at intervals, displacement sensors arranged in the test soil body 2, soil pressure sensors and pore pressure sensors. In the process of filling the test soil body 2, corresponding sensors are arranged as required, when the model pile 3 is provided, the strain gauge is attached to the model pile 3 as required and resin is coated, so that the strain gauge is prevented from being damaged by the test soil body 2 in the pile sinking process, and a waterproof effect is achieved. During pile sinking, the computer 51 collects sensing information (including strain information of the model pile 3 and displacement information, soil pressure information and pore pressure information of the test soil 2) of various sensors in real time in a one-to-one correspondence manner by various collectors 52.

The test method is suitable for a pile sinking half model test, a single-pile sinking half model test (as shown in figure 4) can be carried out, a multi-pile sinking half model test (as shown in figure 5) can also be carried out, and in the pile sinking process, the displacement change of the color mark layer 21 (namely the test soil body 2) can be observed more visually through the transparent baffle 13 besides sensing the displacement change of the test soil body 2 through the displacement sensor. In order to record the observed displacement change in real time, the monitoring system of the present embodiment preferably further comprises a high-speed camera 53, the high-speed camera 53 is arranged outside the mold box and the lens is aligned with the transparent barrier 13 before the pile sinking test is performed, and the displacement change of the color mark layer 21 is recorded by real-time scanning of the high-speed camera 53 when the pile sinking test is performed.

The invention also provides another pile sinking model test method, which comprises the following steps:

step 21, assembling the mold box 1, assembling the U-shaped first mold half 11 and the U-shaped second mold half 12, and connecting the U-shaped opening side of the second mold half 12 and the U-shaped opening side of the first mold half 11 in a butt joint manner. A second mold box configuration was formed for full model testing.

And 22, filling the test soil body 2 in the model box 1.

Step 23, installing the movable bracket 13, installing a beam 141 across above the first half mold chamber 11, installing a horizontal moving device 142 on the beam 141 in a sliding manner along the length direction, and connecting the load applying device 4 to the horizontal moving device 142.

And 24, sinking the pile to provide a model pile 3, applying an external load to the pile top of the model pile 3 by using the load applying device 4 to enable the model pile 3 to sink into the test soil body 2, and monitoring the model pile 3 and the test soil body 2 by using a monitoring system in the pile sinking process.

The test method is suitable for the full-model test of the pile sinking with larger test space requirements, but the test condition in the box cannot be directly observed from the outside of the box. Therefore, in step 21, the second mold half 12 is butted against the first mold half 11 without blocking the transparent barrier 13. In step 22, only the test soil 2 needs to be filled in layers, and the color mark layer 21 does not need to be arranged. In step 24, only the relevant information of the model pile 3 and the test soil 2 is acquired through the sensor and the acquisition instrument 52, and the high-speed camera 53 is not required to be arranged to observe the displacement change of the soil.

As a preferred embodiment:

the bottom end of the first half mould chamber 11 is blocked by a bottom plate 111 and the bottom of the first half mould chamber 11 is provided with a drain valve 112.

After filling the test soil 2 and before pile sinking, performing saturation treatment on the test soil 2, opening the drainage valve 112 to inject water into the model box 1 under pressure, so that the water body moves from bottom to top from the bottom of the test soil 2 until the water body overflows the surface of the test soil 2, closing the drainage valve 112, and standing for 24-48 hours.

As a preferred embodiment:

the first and second mold half chambers 11 and 12 are each formed by axially splicing a plurality of mold chamber modules. When the model box 1 is assembled, the height of the model box 1 is reasonably set according to the final penetration depth of the model pile 3, the model box is assembled, and vaseline is coated on the inner wall of the model box 1 after the model box 1 is assembled and before the test soil 2 is filled.

After pile sinking is finished, the model box 1 is disassembled layer by layer from top to bottom, and soil around the pile is sampled simultaneously, so that the disturbance influence of pile body penetration on adjacent soil is researched.

While the present invention has been described in detail and with reference to the embodiments thereof as illustrated in the accompanying drawings, it will be apparent to one skilled in the art that various changes and modifications can be made therein. Therefore, certain details of the embodiments are not to be interpreted as limiting, and the scope of the invention is to be determined by the appended claims.