CN110567870B - Pile soil interface friction visualization test device and method - Google Patents
Pile soil interface friction visualization test device and method Download PDFInfo
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- CN110567870B CN110567870B CN201910940989.7A CN201910940989A CN110567870B CN 110567870 B CN110567870 B CN 110567870B CN 201910940989 A CN201910940989 A CN 201910940989A CN 110567870 B CN110567870 B CN 110567870B
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Abstract
A pile soil interface friction visualization test device and a method belong to the technical field of buildings. Pile soil interface friction visual test device, including model box, loading plate, reaction frame, servo loading motor and jack, be provided with model pile and sand layer in the model box, pre-buried a plurality of soil pressure sensor in the sand layer, the reaction frame includes rigid screw rod, reaction beam and first electric lift stand motor, the reaction beam middle part is provided with servo loading motor, servo loading motor lower extreme is fixed with the pressure head for apply pressure to the model pile, simulate the complicated atress condition of model pile, servo loading motor's bilateral symmetry is provided with the jack, is used for applying the overburden pressure to the sand layer. The pile-soil interface friction visualization test device and method are reasonable in structure and simple to operate, and can be used for researching pile-soil contact surface friction characteristics and sand deformation rules of different pile circumferences and pile ends, different sand layer covering pressures, different pile surface roughness and elongation ratios.
Description
Technical Field
The invention relates to the technical field of buildings, in particular to a pile soil interface friction visualization test device and method.
Background
With the rapid development of urban construction in China, a plurality of high-rise and super high-rise buildings appear, and the requirement on foundation bearing capacity is high. Pile foundations are widely applied to foundation engineering as a main foundation form, and along with accumulation of pile foundation engineering actual engineering experience and deep theoretical research, a plurality of novel pile foundations such as extruded and expanded support disc piles, spiral piles, bamboo joint piles, bored soil extruded piles and the like are formed on the foundation of bored piles and precast tubular piles. Long piles in deep soft soil areas are generally friction piles or end bearing friction piles, and pile foundation bearing capacity is mainly provided by side friction resistance. The pile side friction resistance calculation formula given in the conventional pile foundation specification is mainly an empirical formula given based on field test data, and has larger deviation from the actually measured pile side friction resistance value in a plurality of actual projects. The friction performance of pile soil contact surfaces of pile foundations of different types is researched by combining a model test, and a theoretical basis is provided for pile foundation design in actual engineering. A large number of test results show that the pile-soil contact surface form, the pile surface roughness, the pile periphery soil body property and the pile periphery soil body stress level can influence the pile side friction performance, moreover, the pressure born by the pile end surface is complex, and the specific stress condition is difficult to be met by applying pressure to the pile by using vertical pressure alone, so that the method has very important significance in researching the friction characteristics and the sand deformation of different types of pile-soil contact surfaces under the action of different overlying pressures.
At present, research on pile soil contact surfaces is mainly based on field tests and indoor shear tests (direct shear tests and ring shear tests). In the research of pile soil contact surface friction performance in the field test, pile side friction resistance values are mainly converted based on pile shafts measured by pile shaft reinforcing steel bar stress meters or optical fibers, pile soil relative displacement is pile shaft displacement, pile circumference soil displacement is not considered, in addition, soil distribution conditions in actual engineering are complex, and therefore accurate pile side friction resistance pile soil relative displacement relation cannot be obtained. The indoor shear test mainly comprises a pile soil contact surface direct shear test and a ring shear test, the indoor shear test can measure accurate pile soil relative displacement, but the direct shear test and the ring shear test cannot obtain shear stress and pile soil relative displacement at different distances from a pile soil interface, and meanwhile, due to a closed experimental environment, the deformation rule of sand soil cannot be intuitively known, so that the friction characteristic of the pile soil contact surface and the sand soil deformation rule cannot be fully known and seen when the pile soil contact surface friction characteristic and the sand soil deformation rule are analyzed.
Disclosure of Invention
In order to solve the technical problems of field tests and indoor shear tests in the prior art, the invention provides a pile-soil interface friction visualization test device and method capable of simulating the relative compactness of sand soil layers at different pile circumferences and pile ends, different sand soil layer coating pressures, different pile surface roughness and different elongation ratios.
In order to achieve the above object, the technical scheme of the present invention is as follows:
A pile soil interface friction visualization test device comprises a model box, a loading plate, a reaction frame, a servo loading motor and a jack;
The model box is of a cylindrical structure with upper and lower openings and is arranged on the base, a model pile and a sand layer are arranged in the model box, and a plurality of soil pressure sensors are embedded in the sand layer;
The loading plate is a circular plate with a through hole in the center, is arranged above the sand layer and is embedded into the model box;
The reaction frame is fixedly arranged on the base and comprises a rigid screw rod, a reaction beam and a first electric lifting stand column motor, and a servo loading motor is arranged in the middle of the reaction beam and used for applying pressure to the model pile; jacks are symmetrically arranged on two sides of the servo loading motor and used for applying covering pressure to the sand layer;
the servo loading motor and the soil pressure sensor are connected with a computer through a receiving device.
The pile soil interface friction visualization test device further comprises a three-dimensional scanning recognition device, the three-dimensional scanning recognition device comprises an annular frame, a metal detector arranged on the inner side of the annular frame and a second electric lifting stand column motor arranged on two sides of the annular frame, the annular frame is arranged on the outside of the model box, the metal detector is connected with a computer and used for realizing visualization of sand deformation, and the second electric lifting stand column motor is arranged on the rigid screw and used for driving the annular frame to move up and down.
The sand layer comprises a marked sand layer and an unmarked sand layer, metal powder is uniformly doped into the sand in the marked sand layer, the metal powder is arranged around the model pile, and a plurality of soil pressure sensors are uniformly arranged in the marked sand layer.
The soil pressure sensor is vertically arranged or horizontally arranged, the soil pressure sensor is vertically arranged and used for measuring the peripheral soil pressure of the pile, and the soil pressure sensor is horizontally arranged and used for measuring the overlying pressure of the sand layer and the friction force of the pile soil.
The loading mode of the servo loading motor is displacement control or load control, and when load control is adopted, the limit loading value of the servo loading motor is 20kN, and the stroke is 50mm; when displacement control is adopted, the loading speed of the servo loading motor is 0.1-5mm/min.
The servo loading motor is characterized in that a pressure head is fixedly arranged below the servo loading motor, the lower end face of the pressure head is an inclined face, and the upper end face of the model pile is an inclined face matched with the lower end face of the pressure head so that the upper end face of the model pile is attached to the lower end face of the pressure head.
Pile soil interface friction visual test device still includes the flexible chain of a plurality of vertical setting, the flexible chain links firmly with the counter-force beam, the flexible chain is provided with the draw-in groove for fixed soil pressure sensor.
The base comprises a bottom plate and an annular support, the bottom plate is welded above the annular support, and a first annular groove and a second annular groove are sequentially formed in the upper surface of the bottom plate from inside to outside and are respectively used for placing a first partition plate and a second partition plate.
The pile soil interface friction visualization test method adopts the pile soil interface friction visualization test device and comprises the following steps:
Prefabricating a model pile with set slenderness ratio, roughness and pressurizing angle;
Inserting a first partition plate into a first annular groove on the upper surface of the bottom plate, filling a marked sand layer on the bottom plate positioned in the first partition plate to a set height, and placing a model pile on the filled marked sand layer;
Inserting a second partition plate into a second annular groove on the upper surface of the bottom plate, filling a marked sand layer between the first partition plate and the second partition plate to a set position, then extracting the first partition plate, filling an unmarked sand layer between the second partition plate and the inner wall of the model box, and then extracting the second partition plate;
Covering a loading plate on the upper surface of the filled sandy soil layer, applying an overlying pressure to the sandy soil layer by a jack, adjusting the value of the applied overlying pressure by a soil pressure sensor which is embedded in the marked sandy soil layer and horizontally arranged, and after the overlying pressure reaches a set value, driving an annular frame and a metal detector to move up and down by a second electric lifting stand column motor to scan the marked sandy soil layer for the first time, and receiving soil deformation data by a computer and recording; and then, loading the model pile by a servo loading motor, stopping loading after the model pile is loaded to a set value, driving the annular frame and the metal detector to move up and down by a second electric lifting stand column motor to scan the marked sand layer for the second time, and receiving soil deformation data by a computer and recording.
Compared with the prior art, the invention has the beneficial effects that:
1) The compactness of the filled sand layer can be changed according to the test requirement, and the influence of different sand layer compactibility on the friction characteristics of the pile soil contact surface can be studied;
2) According to the invention, the soil pressure sensor pre-buried in the sand layer can measure the horizontal soil pressure and the vertical soil pressure, and the arrangement of the sensors adopts a flexible-chain arrangement method, so that the position stability of the soil pressure sensor is ensured;
3) The model pile is a cylindrical model pile, so that the pile soil shearing surface form is the same as the actual pile soil shearing surface form, and the model box is a cylindrical model box, so that the boundary conditions are similar to those in the actual pile foundation load transmission process, and the reliability of the test result is ensured;
4) The invention adopts the counterforce beam to control the height through the first electric lifting upright post motor, so as to ensure that model piles with different slender ratios finish the test;
5) According to the invention, the pile periphery and the method for completely burying the lower end of the pile into soil are adopted, so that the test device can measure the friction property change between the lower end of the pile and the pile periphery;
6) In the invention, the jack is adopted to apply the overburden pressure to the sandy soil layer, and the overburden pressure can be adjusted by changing the load applied by the jack;
7) According to the invention, the displacement control or load control servo loading motor is adopted to load the pile soil contact surface shear test, so that the requirements of the shear test of various pile soil contact surfaces under various different shear speeds and different load pressures can be met;
8) The annular three-dimensional scanning recognition device adopted in the invention is fixed on the rigid screw rod through the second electric lifting upright motor, and controls the scanning speed to ensure that the marked soil body is sufficiently recognized;
9) The pressure changes of all parts can be displayed in real time through the receiving device and the computer, and the sandy soil deformation condition can be scanned through the three-dimensional scanning and identifying device to obtain a three-dimensional image on the computer, so that real-time observation of experimental data and comparison of sandy soil deformation before and after pile soil friction test are realized;
10 According to the invention, the pressure head with the inclined surface at the lower end face is adopted and matched with the upper end face of the model pile, so that pile soil friction shearing working conditions under different pressure environments can be simulated.
Additional features and advantages of the invention will be set forth in part in the detailed description which follows.
Drawings
FIG. 1 is a schematic structural view of a pile-soil interface friction visualization test device provided by an embodiment of the invention;
Fig. 2 is a schematic diagram of the cooperation of the upper end face of the model pile and the lower end face of the pressure head according to the embodiment of the invention.
Reference numerals in the drawings of the specification include:
1. The model box, 2, the bottom plate, 3, annular support, 4, mark sand layer, 5, unmarked sand layer, 6, soil pressure sensor, 7, loading plate, 8, rigid screw, 9, counter-force beam, 10, second electric lift stand motor, 11, servo loading motor, 12, first electric lift stand motor, 13, annular frame, 14, jack, 15, model stake, 16, pressure head, 17, flexchain.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention.
In the description of the present invention, it should be understood that the terms "longitudinal," "transverse," "vertical," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, mechanical or electrical, or may be in communication with each other between two elements, directly or indirectly through intermediaries, as would be understood by those skilled in the art, in view of the specific meaning of the terms described above.
In order to solve the problems in the prior art, as shown in fig. 1 to 2, the embodiment of the invention provides a pile-soil interface friction visualization test device and method capable of simulating the relative compactness of sand soil layers at different pile circumferences and pile ends, different sand soil layer coating pressures, different pile surface roughness and different slenderness ratios.
As shown in fig. 1 to 2, a pile-soil interface friction visualization test device comprises a model box 1, a loading plate 7, a reaction frame, a servo loading motor 11 and a jack 14. The model box 1 is of a cylindrical structure with upper and lower openings, the model box is arranged on a base, a model pile 15 and a sand layer are arranged in the model box 1, a plurality of soil pressure sensors 6 are embedded in the sand layer and used for measuring horizontal soil pressure and vertical soil pressure of the periphery and the lower end of the model pile 15, the soil pressure sensors 6 are vertically arranged or horizontally arranged, the soil pressure sensors 6 are vertically arranged and used for measuring soil pressure around the pile, the soil pressure sensors 6 are horizontally arranged and used for measuring the overburden pressure of the sand layer and the pile soil friction force, when the soil pressure sensors 6 are used for measuring the overburden pressure of the sand layer, the jacks 14 are adjusted according to the readings of the soil pressure sensors 6, and when the soil pressure sensors 6 are used for measuring the pile soil friction force, the pile soil friction force is obtained by observing the readings of the soil pressure sensors 6 in the process of applying pressure to the model pile 15 by the servo loading motor 11. The sand layer comprises a marked sand layer 4 and an unmarked sand layer 5, the marked sand layer 4 is a sand layer doped with metal powder, namely, the sand in the marked sand layer 4 is uniformly doped with the metal powder, the marked sand layer is arranged around a model pile 15, the unmarked sand layer 5 is a sand layer not doped with the metal powder, the unmarked sand layer is arranged between the marked sand layer and the inner wall of the model box 1, a plurality of soil pressure sensors 6 are uniformly arranged in the marked sand layer 4, and the model pile 15 can be arranged at the axial line of the model box 1. The loading plate 7 is a circular plate with a through hole in the center, is arranged above the sand layer, and is embedded in the model box 1. Pile soil interface friction visual test device still includes the flexible chain 17 of a plurality of vertical setting, and flexible chain 17 links firmly with reaction beam 9, flexible chain 17 is provided with the draw-in groove for fixed soil pressure sensor 6.
In the embodiment, the model box 1 is made of PC endurance plates with the thickness of 10mm, the diameter of the PC endurance plates is 900mm, a marked sand layer 4 and an unmarked sand layer 5 with certain compactness are filled in the model box 1, the compactness of the sand is determined according to experimental requirements, and the annular support 3 is two annular steel plates with the thickness of 50mm, and the height of the annular support is 200mm. The lower end part of the model pile 15 is completely arranged in the sand layer, the model pile 15 is uniformly and fixedly arranged around the model pile 15 through a flexible chain 17, the flexible chain 17 is connected with a top counter-force beam 9 to ensure vertical arrangement, so that the measurement result of the soil pressure sensor 6 has a reference meaning, and the inclined surface of the upper end surface of the model pile 15 is set according to actual engineering requirements, namely the pressurizing angle of the model pile 15 is set. The model of the soil pressure sensor 6 is: BX-1 type, uniformly arranged around the portion of the mold pile 15 located inside the marker sand layer 4.
As shown in fig. 1 to 2, the reaction frame is fixedly arranged on the base, the base comprises a bottom plate 2 and an annular support 3, the bottom plate 2 is welded above the annular support 3, a first annular groove and a second annular groove are sequentially formed in the upper surface of the bottom plate 2 from inside to outside and are respectively used for placing a first partition plate and a second partition plate, and the radial distance between the first partition plate and the second partition plate is less than or equal to 5cm. The reaction frame comprises a rigid screw rod 8, a reaction beam 9 and a first electric lifting stand column motor 12, and the rigid screw rod 8 is fixedly arranged on the bottom plate 2. The middle part of the counter-force beam 9 is provided with a servo loading motor 11 for applying pressure to the model pile 15; jacks 14 are symmetrically arranged on two sides of the servo loading motor 11 and are used for applying an overlying pressure to the sand layer. The loading mode of the servo loading motor 11 is displacement control or load control, and when load control is adopted, the limit loading value of the servo loading motor 11 is 20kN, and the stroke is 50mm; when displacement control is adopted, the loading speed of the servo loading motor 11 is 0.1-5mm/min. The pressure head 16 is fixedly arranged below the servo loading motor 11, the lower end face of the pressure head 16 is an inclined face, the upper end face of the model pile 15 is an inclined face matched with the lower end face of the pressure head 16, so that the upper end face of the model pile 15 is attached to the lower end face of the pressure head 16, the inclination degree of the upper end face of the model pile 15 and the lower end face of the pressure head 16 is set according to experimental requirements, and the pressure head 16 and the model pile 15 can be prefabricated. The servo loading motor 11 and the soil pressure sensor 6 are connected with a computer through a DH-3817 dynamic and static strain testing system.
In this embodiment, two rigid screw rods 8 are symmetrically fixed on the bottom plate 2, the bottom plate 2 is a 50mm thick steel plate, the diameter of the steel plate is 1000mm, the upper parts of the two rigid screw rods 8 are connected with the counter-force beam 9, the servo loading motor 11 is located above the model pile 15 and fixedly connected with the counter-force beam 9, and is used for applying pressure to the cylindrical model pile 15 located at the symmetrical center of the model box 1, the load and displacement applied by the servo motor in the loading process can be collected through the receiving device, and the height of the counter-force beam 9 is controlled through the first electric lifting upright motor 12, so that the model pile 15 with different slender ratios can be tested conveniently. The model piles 15 can be filled in the model box 1 in a pre-buried or cast-in-situ mode, and the upper ends of the two jacks 14 are connected with the counter-force beams 9 and symmetrically arranged on two sides of the servo loading motor 11 for applying covering pressure to the sand layer. The receiving device is a DH-3817 dynamic and static strain testing system, and the data of the soil pressure sensor 6 and the servo loading motor 11 received by the receiving device are transmitted to a computer. The servo loading motor 11 can adopt the prior art to realize displacement control or load control, the servo loading motor 11 is connected with a computer through a receiving device, and the servo loading motor 11 is controlled to apply pressure to the model pile 15 through computer adjustment.
As shown in fig. 1, the pile-soil interface friction visualization test device further comprises a three-dimensional scanning recognition device, wherein the three-dimensional scanning recognition device comprises an annular frame 13, a metal detector arranged on the inner side of the annular frame 13 and a second electric lifting stand column motor 10 arranged on two sides of the annular frame 13, the annular frame 13 is arranged on the outside of the model box 1, the metal detector is connected with a computer and used for realizing visualization of sand deformation, and the second electric lifting stand column motor 10 is arranged on the rigid screw rod 8 and used for driving the annular frame 13 to move up and down.
The marked sand layer 4 is different from the unmarked sand layer 5 in that metal powder is uniformly dispersed in the marked sand layer 4, and the metal powder is used for marking, so that the metal detector can conveniently identify to generate a three-dimensional image. The second electric lifting column motor 10 drives the annular frame 13 and the metal detector to move up and down to scan the marked sand layer 4, so as to record the deformation of the soil body around the pile before and after the test, and meanwhile, the speed of the annular frame 13 moving up and down can be controlled to ensure that the marked sand layer 4 is fully identified.
The pile soil interface friction visualization test method adopts the pile soil interface friction visualization test device and comprises the following steps:
prefabricating a model pile 15 with set slenderness ratio, roughness and pressurization angle;
inserting a first partition board into a first annular groove on the upper surface of the bottom plate 2, filling a marked sand layer 4 on the bottom plate 2 positioned in the first partition board to a set height, preferably 5cm, and placing a model pile 15 on the filled marked sand layer 4;
Inserting a second partition board into a second annular groove on the upper surface of the bottom plate 2, filling a marked sand layer 4 between the first partition board and the second partition board to a set position, then drawing the first partition board, filling an unmarked sand layer 5 between the second partition board and the inner wall of the model box 1, and then drawing the second partition board;
The loading plate 7 is covered on the upper surface of the filled sandy soil layer, the jack 14 is used for applying an overlying pressure to the sandy soil layer, the applied overlying pressure value is adjusted through the reading of the soil pressure sensor 6 which is embedded in the marked sandy soil layer 4 and horizontally arranged, after the overlying pressure reaches a set value, the second electric lifting stand column motor 10 drives the annular frame 13 and the metal detector to move up and down for carrying out first scanning on the marked sandy soil layer 4, and soil deformation data are received and recorded through a computer; then, the servo loading motor 11 is used for loading the model pile 15, after the model pile is loaded to a set value, the loading is stopped, the second electric lifting stand column motor 10 drives the annular frame 13 and the metal detector to move up and down to scan the marked sand soil layer 4 for the second time, and soil deformation data are received and recorded through a computer.
In the invention, the sandy soil layer can be replaced by other soil bodies such as clay, silt, loess and the like so as to carry out corresponding shear tests. Filling sand layers by adopting different methods according to the test compactness requirement, wherein the sand filling method is a sand rain method when the test requirement is that the sand layers are smaller in compactness; when the test requires that the compactness of the sand layer is larger, the sand layer filling method is a layering ramming method.
The invention has reasonable structure and simple operation, can be used for researching the relative compactness of the sand soil layers at different pile peripheries and pile ends, the coating pressure of different sand soil layers, the friction characteristics of pile soil contact surfaces with different pile surface roughness and elongation ratio and the sand deformation rule aiming at different influence factors influencing the friction performance of the pile soil, can also measure the shear stress and the sand deformation condition of the pile soil interface at the set position, and provides an effective means for the visual research of the friction performance of the pile soil contact surfaces.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.
Claims (5)
1. The pile soil interface friction visualization test device is characterized by comprising a model box, a loading plate, a reaction frame, a servo loading motor and a jack;
The model box is of a cylindrical structure with upper and lower openings and is arranged on the base, a model pile and a sand layer are arranged in the model box, and a plurality of soil pressure sensors are embedded in the sand layer;
The loading plate is a circular plate with a through hole in the center, is arranged above the sand layer and is embedded into the model box;
The reaction frame is fixedly arranged on the base and comprises a rigid screw rod, a reaction beam and a first electric lifting stand column motor, and a servo loading motor is arranged in the middle of the reaction beam and used for applying pressure to the model pile; jacks are symmetrically arranged on two sides of the servo loading motor and used for applying covering pressure to the sand layer;
the servo loading motor and the soil pressure sensor are connected with a computer through a receiving device;
The three-dimensional scanning and identifying device comprises an annular frame, a metal detector arranged on the inner side of the annular frame and second electric lifting stand column motors arranged on the two sides of the annular frame, wherein the annular frame is arranged outside the model box, the metal detector is connected with a computer and used for realizing visualization of sand deformation, and the second electric lifting stand column motors are arranged on the rigid screw and used for driving the annular frame to move up and down;
the lower end face of the pressure head is an inclined face, and the upper end face of the model pile is an inclined face matched with the lower end face of the pressure head so as to enable the upper end face of the model pile to be attached to the lower end face of the pressure head;
the soil pressure sensor is characterized by further comprising a plurality of flexible chains which are vertically arranged, wherein the flexible chains are fixedly connected with the counter-force beams and are provided with clamping grooves for fixing the soil pressure sensor;
the sand layer comprises a marked sand layer and an unmarked sand layer, metal powder is uniformly doped into the sand in the marked sand layer, the metal powder is arranged around the model pile, and a plurality of soil pressure sensors are uniformly arranged in the marked sand layer.
2. The pile-soil interface friction visualization test device according to claim 1, wherein the soil pressure sensor is vertically arranged or horizontally arranged, the soil pressure sensor is vertically arranged for measuring pile-periphery soil pressure, and the soil pressure sensor is horizontally arranged for measuring overburden pressure of a sand layer and measuring pile-soil friction force.
3. The pile soil interface friction visualization test device according to claim 1, wherein the loading mode of the servo loading motor is displacement control or load control, and when load control is adopted, the limit loading value of the servo loading motor is 20kN, and the stroke is 50mm; when displacement control is adopted, the loading speed of the servo loading motor is 0.1-5mm/min.
4. The pile soil interface friction visualization test device according to claim 1, wherein the base comprises a bottom plate and an annular support, the bottom plate is welded above the annular support, and a first annular groove and a second annular groove are sequentially formed in the upper surface of the bottom plate from inside to outside and are respectively used for placing a first partition plate and a second partition plate.
5. The pile soil interface friction visualization test method adopting the pile soil interface friction visualization test device according to claim 4 is characterized by comprising the following steps:
Prefabricating a model pile with set slenderness ratio, roughness and pressurizing angle;
Inserting a first partition plate into a first annular groove on the upper surface of the bottom plate, filling a marked sand layer on the bottom plate positioned in the first partition plate to a set height, and placing a model pile on the filled marked sand layer;
Inserting a second partition plate into a second annular groove on the upper surface of the bottom plate, filling a marked sand layer between the first partition plate and the second partition plate to a set position, then extracting the first partition plate, filling an unmarked sand layer between the second partition plate and the inner wall of the model box, and then extracting the second partition plate;
Covering a loading plate on the upper surface of the filled sandy soil layer, applying an overlying pressure to the sandy soil layer by a jack, adjusting the value of the applied overlying pressure by a soil pressure sensor which is embedded in the marked sandy soil layer and horizontally arranged, and after the overlying pressure reaches a set value, driving an annular frame and a metal detector to move up and down by a second electric lifting stand column motor to scan the marked sandy soil layer for the first time, and receiving soil deformation data by a computer and recording; and then, loading the model pile by a servo loading motor, stopping loading after the model pile is loaded to a set value, driving the annular frame and the metal detector to move up and down by a second electric lifting stand column motor to scan the marked sand layer for the second time, and receiving soil deformation data by a computer and recording.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910940989.7A CN110567870B (en) | 2019-09-30 | 2019-09-30 | Pile soil interface friction visualization test device and method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910940989.7A CN110567870B (en) | 2019-09-30 | 2019-09-30 | Pile soil interface friction visualization test device and method |
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| Publication Number | Publication Date |
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| CN110567870A CN110567870A (en) | 2019-12-13 |
| CN110567870B true CN110567870B (en) | 2024-07-30 |
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| CN112160351A (en) * | 2020-09-01 | 2021-01-01 | 温州大学 | Energy pile bearing performance testing device and operation method thereof |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106769478A (en) * | 2017-01-23 | 2017-05-31 | 浙江大学 | A kind of pile-soil interface shearing test device |
| CN108181180A (en) * | 2018-01-19 | 2018-06-19 | 浙江大学 | It is a kind of to simulate the experimental rig and method for causing the variation of negative friction of pile neutral point by ground preloading |
| CN210720113U (en) * | 2019-09-30 | 2020-06-09 | 辽宁工程技术大学 | Pile-soil interface friction visual test device |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU958585A1 (en) * | 1980-06-30 | 1982-09-15 | Государственный институт по проектированию оснований и фундаментов "Фундаментпроект" | Method of measuring the depth of penetration of pile into earth |
| JPS6153911A (en) * | 1984-08-23 | 1986-03-18 | Toa Harbor Works Co Ltd | Device of measuring peripheral surface friction force of pile |
| DE4027020C2 (en) * | 1990-08-27 | 1994-08-25 | Heinrich Liebig Gmbh | Method and device for determining the presence of metallic reinforcement elements in the interior of a concrete component |
| CN201087419Y (en) * | 2007-09-29 | 2008-07-16 | 郑新俊 | Exactly located immersed tube for construction |
| ITUB20155405A1 (en) * | 2015-10-20 | 2016-01-20 | Luca Maritano | RECLAIMING ROPE SYSTEM, THE RISALITY |
| CN105716970B (en) * | 2016-04-26 | 2018-10-09 | 河海大学 | Shaped pile Pile-soil contact face failure mode visual test device and application method |
| CN105699289B (en) * | 2016-04-26 | 2018-08-17 | 河海大学 | A kind of test device and its application method of PCC internal friction |
| CN106596297B (en) * | 2017-03-05 | 2020-10-16 | 南京大学 | Energy pile-soil interface mechanics behavior characteristic test equipment and method |
| CN107036914B (en) * | 2017-06-21 | 2023-07-18 | 辽宁工程技术大学 | Device and method for measuring friction angle of retaining wall and contact soil body interface |
| CN107905202B (en) * | 2017-11-09 | 2019-09-06 | 东南大学 | The migration path of filler detects experimental provision when high rheology weak soil dynamic replacement |
| CN108106949B (en) * | 2017-12-04 | 2023-09-08 | 深圳大学 | Method for in-situ test of shear strength of pile-soil interface and symmetrical direct shear apparatus |
| CN108037022A (en) * | 2017-12-19 | 2018-05-15 | 浙江大学 | A kind of stake Soil Interface shearing test device and test method based on picture catching |
| CN207730580U (en) * | 2018-01-19 | 2018-08-14 | 浙江大学 | A kind of simulation is caused the experimental rig of negative friction of pile neutral point variation by ground preloading |
-
2019
- 2019-09-30 CN CN201910940989.7A patent/CN110567870B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106769478A (en) * | 2017-01-23 | 2017-05-31 | 浙江大学 | A kind of pile-soil interface shearing test device |
| CN108181180A (en) * | 2018-01-19 | 2018-06-19 | 浙江大学 | It is a kind of to simulate the experimental rig and method for causing the variation of negative friction of pile neutral point by ground preloading |
| CN210720113U (en) * | 2019-09-30 | 2020-06-09 | 辽宁工程技术大学 | Pile-soil interface friction visual test device |
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