CN110331743B - Test device and test method for testing bearing performance of enlarged head of pile end of static drilling root planting pile - Google Patents
Test device and test method for testing bearing performance of enlarged head of pile end of static drilling root planting pile Download PDFInfo
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- 230000003068 static effect Effects 0.000 title claims abstract description 39
- 238000005553 drilling Methods 0.000 title claims abstract description 38
- 238000012360 testing method Methods 0.000 title claims abstract description 37
- 238000010998 test method Methods 0.000 title claims abstract description 13
- 239000002689 soil Substances 0.000 claims abstract description 69
- 239000004576 sand Substances 0.000 claims abstract description 51
- 239000002002 slurry Substances 0.000 claims abstract description 36
- 239000004568 cement Substances 0.000 claims abstract description 34
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 18
- 239000010959 steel Substances 0.000 claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000011148 porous material Substances 0.000 claims abstract description 12
- 229910000838 Al alloy Inorganic materials 0.000 claims abstract description 5
- 238000003466 welding Methods 0.000 claims abstract description 4
- 238000002347 injection Methods 0.000 claims abstract 3
- 239000007924 injection Substances 0.000 claims abstract 3
- 239000007788 liquid Substances 0.000 claims description 16
- 238000013461 design Methods 0.000 claims description 10
- 230000001105 regulatory effect Effects 0.000 claims description 10
- 238000005429 filling process Methods 0.000 claims description 7
- 239000011521 glass Substances 0.000 claims description 2
- 238000000034 method Methods 0.000 description 14
- 238000011160 research Methods 0.000 description 7
- 238000010276 construction Methods 0.000 description 6
- 238000006073 displacement reaction Methods 0.000 description 6
- 230000001788 irregular Effects 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
Abstract
The invention discloses a test device and a test method for testing the bearing performance of an enlarged head of a pile end of a static drilling root planting pile. The device comprises a model box, a loading plate, a counter-force beam, a loading motor, a circular die, an air compressor and a slurry storage tank. The model box is formed by welding steel plates, sand is filled in the model box, and a pore water pressure sensor, a soil pressure sensor and a circular die are buried in the sand; the circular mold is formed by combining two semicircular aluminum alloy plates through bolt connection; the slurry storage tank is a circular barrel for storing cement soil slurry, the slurry storage tank, the air compressor and the model box are connected through a slurry injection pipe, and the slurry injection pipe stretches into a space reserved by the circular mold; the loading plate is placed on the upper surface of the sand layer, and the jack is used for applying the overlying pressure to simulate different stress levels; the static drilling root planting model pile in the model box can be loaded through the loading motor. The device has reasonable structure and simple operation, and provides an effective means for researching the bearing performance of the enlarged head of the pile end of the static drilling root planting pile.
Description
Technical Field
The invention relates to a test device for researching pile end bearing performance in the field of geotechnical engineering, in particular to a test device and a test method for testing pile end expanding head bearing performance of a static drilling root planting pile, which can be used for researching pile bearing characteristics of the static drilling root planting pile when sand relative densities are different, pile end expanding head diameters are different, pile end cement soil strengths are different, grouting pressures are different and coating pressures are different.
Background
Along with the rapid development of urban construction in China, projects such as high-speed railways, large-span bridges, complex underground infrastructures and the like of super high-rise buildings appear, and the requirements on foundation bearing capacity are high. Pile foundations are widely applied to foundation engineering as a main foundation form, and the pile foundations currently applied to practical engineering mainly comprise prestressed pipe piles and bored piles, however, the two pile types have some defects in practical engineering application.
Soil squeezing effect and noise pollution can be generated in the traditional prestressed pipe pile construction process, a large amount of slurry can be generated in the bored pile construction process, and the problems of slurry discharge and slurry pollution are widely paid attention to society. In recent years, with the accumulation of practical engineering experience of pile foundation engineering and the deep theoretical research, the pile foundation is on some new pile foundations. The static drilling root planting pile is a novel combined pile foundation consisting of a prestressed pipe pile and cement soil around the pile, the soil squeezing effect cannot be generated in the construction process, and most of slurry in drilling is mixed with cement slurry to form cement soil after being stirred, so that the discharge amount of the slurry is greatly reduced. The static drilling root planting pile is successfully applied to southeast coastal areas in China at present, and great social and economic benefits are obtained. Because the construction process of the static drilling root planting pile is different from that of the traditional pile foundation, and the pile end of the static drilling root planting pile is provided with a cement soil expansion head, the pile end bearing performance of the static drilling root planting pile is different from that of the traditional pile foundation, and the pile end bearing capacity of the static drilling root planting pile cannot be calculated by the existing pile end bearing capacity calculation formula. The pile end bearing characteristics of the static drilling root planting pile are researched by combining a model test, and a theoretical basis is provided for the design of the static drilling root planting pile in actual engineering.
At present, the research on the bearing performance of the pile end is mainly based on field tests and model tests, and is mainly based on traditional prestressed pipe piles and bored piles. In the research of pile end bearing performance in the field test, pile end bearing force is mainly converted based on the reading of a pile body steel bar stress meter near the pile end or is directly measured by a pile end soil pressure sensor buried at the pile end; the displacement measurement of the pile end is very difficult, and the estimation is mainly carried out according to the pile top displacement and the pile body compression; the research on pile end bearing performance in the field test at present is mainly based on prestressed pipe piles, bored piles and post-grouting bored piles at the pile ends. The grouting pipe is pre-buried in the pile end position in the pile end post grouting bored pile, grouting is carried out in the pile end position through the pre-buried grouting pipe after pile foundation construction is finished, the injected slurry is cement paste, the grouting body is irregular in shape, and the pile end bearing performance is quite complex. The research on pile end bearing performance in the model test is mainly based on the traditional prestressed pipe pile and the bored pile and the pile end post grouting bored pile, and a relatively accurate pile end load displacement relation curve can be obtained in the model test, however, the shape of a grouting body at the pile end position of the pile end post grouting bored pile in the model test is also irregular, the discreteness of pile end bearing capacity is larger, and the pile end bearing performance is unstable.
At present, the research on the bearing performance of the pile end of the Yu Jing root drilling and planting pile is very little, the pile end of the static root drilling and planting pile is provided with a uniformly stirred cement-soil enlarging head, the bearing performance of the pile end is different from that of the traditional prestressed pipe pile and the traditional bored pile, the pile end bearing performance of the pile end post-grouting bored pile is similar to that of the static root drilling and planting pile, however, the pile end in the pile end post-grouting bored pile is directly injected with cement paste, the cement paste is irregular in shape, the bearing performance of the pile end is unstable, and the difference of the ultimate bearing capacity of the pile end is larger; the shape of the enlarged head of the cement soil at the pile end position of the static drilling root planting pile is regular (cylindrical), the cement soil is fully stirred, the strength is uniform, and the pile end has stable bearing performance and higher bearing capacity. Therefore, the method has very important significance in researching the bearing performance of the pile end of the static drilling root planting pile. However, the existing field test and model test cannot simulate the bearing performance of the enlarged head of the pile end of the static drilling root planting pile.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a test device and a test method for testing the bearing performance of the enlarged head of the static drilling root planting pile end, and the device can be used for simulating the relative compactness of soil bodies of different pile ends, different stress levels, different diameters of the enlarged head of the pile end and the bearing characteristics of the pile bearing of the static drilling root planting pile under different grouting pressures, and can ensure that the shape of the enlarged head of the pile end is similar to that of the enlarged head of the pile end of the static drilling root planting pile in actual engineering.
The technical scheme adopted for solving the technical problems is as follows:
test device of static root of boring pile end enlarged footing bearing performance of planting of test, its characterized in that: comprises a model box, a loading plate, a counter-force beam, a loading motor, a round die, an air compressor and a slurry storage tank,
the model box is formed by welding steel plates, I-steel is welded on the side surface and the bottom of the model box to increase the rigidity of the model box, and a steel support is welded on the bottom of the model box; a sand layer is filled in the model box; a plurality of soil pressure sensors and a plurality of pore water pressure sensors are embedded in the sandy soil layer;
a circular mold is embedded in the sandy soil layer; the circular mold is a hollow cylinder and is formed by combining two semicircular aluminum alloy plates through bolt connection, and a reserved space is formed in the circular mold; the center of the model box is also provided with a model pile which is hung on the counter-force beam, and the pile end of the model pile is positioned at the center of a reserved space in the circular die;
the loading plate is a square plate with a through hole in the center and is arranged on the sand layer, and the model pile penetrates through the through hole; two steel cushion blocks are arranged above the loading plate and symmetrically distributed on two sides of the loading motor, and a jack is arranged above each steel cushion block;
the counter-force beam is welded on the model box and is propped against the upper end of the jack; the loading motor is positioned above the model pile and is fixed on the counter-force beam;
the slurry storage tank is internally provided with liquid cement soil which is uniformly stirred, and is provided with a pressure release valve, a pressure regulating switch and a grouting pipe; the grouting pipe is provided with a grouting valve, the end part of the grouting pipe is required to be buried in a reserved space, and liquid cement soil is injected into the reserved space;
the air compressor is provided with a through air pipe, a pressure gauge and a pressure regulating switch are arranged on the through air pipe, and the air pipe is used for inputting air pressure into the pulp storage tank.
In the above technical scheme, further, the ratio of the side length of the model box to the diameter of the circular die is not less than 10.
Further, the ratio of the distance between the bottom of the circular mold and the bottom of the mold box to the diameter of the circular mold is not less than 10.
Further, the jack loads the sand layer through the loading plate, and different stress levels are simulated.
Further, the diameter of the model pile is smaller than that of the circular mould.
Further, the limiting loading value of the loading motor is 200kN, and the stroke is 100mm.
Further, the diameter of the central round hole of the loading plate is the same as that of the model pile.
Further, the side wall of the slurry storage tank is made of transparent organic glass, and volume scales are marked on the side wall.
Further, the cement soil sample is stirred uniformly in the slurry storage tank, the water content of the cement soil sample exceeds the liquid limit water content, and the cement soil sample is in a liquid state.
The invention also provides a test method for researching the bearing performance of the enlarged head of the pile end of the static drilling root planting pile by adopting the device, which comprises the following steps:
filling sand in a model box, embedding a soil pressure sensor, a pore water pressure sensor and a circular mold in the filling process, embedding a grouting pipe into a reserved space, placing a model pile in the center of the model box, fixing the model pile on a counter-force beam, enabling the pile end of the model pile to be positioned in the center of the reserved space in the circular mold, plugging the bottom of the model pile, and closing the top end of the circular mold; when the filling height of the sand is the same as the top height of the circular mould, an air compressor and a slurry storage tank are installed, liquid cement soil which is uniformly stirred is filled in the slurry storage tank, the air compressor is regulated to enable the slurry storage tank to reach a designed grouting pressure value, the designed grouting pressure is maintained, grouting is started in a reserved space, and the circular mould is slowly taken out of the sand while grouting, so that the reserved space of the circular mould is filled with the liquid cement soil slurry, and a pile end expansion head is formed; filling a sand layer with the thickness of 20-50cm on the top of the sand layer after grouting is finished for 7-28 days, covering a loading plate on the upper surface of the filled sand layer, and applying an overlying pressure to the sand layer by a jack to ensure that the applied overlying pressure value reaches a design pressure value and maintains stability; and loading the model pile by a loading motor 28-90 days after grouting.
Compared with the prior art, the invention has the beneficial effects that:
1. in the invention, a circular mould is adopted to reserve a cement soil grouting space in the sand filling process, and cement soil which is uniformly stirred is injected into the reserved space, so that the form of the pile end expansion head is similar to that of a static drilling root pile planting pile end expansion head in actual engineering.
2. The compactness of the filled sandy soil can be changed according to the requirements, the influence of different compactness of the sandy soil layer at the pile end on the bearing performance of the pile end of the static drilling root planting pile can be studied, the grouting pressure and the pressure dissipation rule in the sandy soil layer can be measured by the pore water pressure sensor embedded in the sandy soil layer, and the soil pressure dissipation rule in the soil body at the pile end can be measured by the soil pressure sensor embedded in the sandy soil layer.
3. The diameter of the embedded circular die can be adjusted, so that the diameter of the pile end expansion head can be changed; simultaneously, the air compressor and the grouting tank can adjust grouting pressure.
4. 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.
5. According to the invention, the static drilling root planting model pile is loaded by adopting the loading motor, so that the test requirements of the research on the bearing performance of the pile end of the static drilling root planting model pile under the conditions of different sand compactness, different overlying pressure (stress level), different enlarged head diameters and different grouting pressure can be met.
Drawings
FIG. 1 is a model box test chart;
FIG. 2 is a schematic view of a loadboard;
FIG. 3 is a top view of a circular mold;
FIG. 4 is a test chart of a test device for the study of the bearing performance of the enlarged head of the pile end of a complete static drilling root planting pile;
in the figure: the hydraulic grouting device comprises a model box 1, I-steel 1-1, a steel support 1-2, a sand layer 1-3, a soil pressure sensor 1-4, a pore water pressure sensor 1-5, a model pile 1-6, a reserved space 1-7, a loading plate 2, a rigid cushion block 2-1, a jack 2-2, a counter-force beam 3, a loading motor 4, a round die 5, semicircular aluminum alloy plates 5-1,5-2, bolts 5-3, an air compressor 6, a pressure gauge 6-1, a pressure regulating switch 6-2, a gas pipe 6-3, a slurry storage tank 7, a pressure release valve 7-1, a pressure regulating switch 7-2, a grouting valve 7-3, a grouting pipe 7-4 and liquid cement soil 7-5.
Detailed Description
The invention will be further described with reference to the drawings and examples.
As shown in fig. 4, the invention relates to a test device for testing pile end expansion head bearing performance of static drilling root planting pile, which can simulate the relative compactness of soil bodies at different pile ends, different stress levels, different pile end expansion head diameters and different grouting pressures, and comprises seven parts, namely a model box 1, a loading plate 2, a counter-force beam 3, a loading motor 4, a circular die 5, an air compressor 6 and a slurry storage tank 7.
The square model box 1 is formed by welding steel plates, I-steel 1-1 is welded at the top, the bottom and the middle of the side surface of the model box respectively, two I-steel 1-1 are welded at the bottom of the model box to increase the overall rigidity of the model box, and the side length and the height of the model box 1 are 2m; filling a sand layer 1-3 with a certain compactness in the model box 1; the sand layers 1-3 are filled by adopting different methods according to the design compactness requirement; the sand layer filling method is a sand rain method (when the design compactness is smaller) and a layering ramming method (when the design compactness is larger); the soil pressure sensor 1-4 and the pore water pressure sensor 1-5 are embedded in the sand layer 1-3 in the filling process, and the soil pressure sensor 1-4 and the pore water pressure sensor 1-5 are respectively embedded at 0m,0.5m and 1.0m depth below the bottom of the circular mold 5; the soil pressure sensor 1-4 is used for measuring the soil pressure of the pile end soil body, and the pore water pressure sensor 1-5 is used for measuring grouting pressure and pressure dissipation rules in the sandy soil layer; in the filling process of the sand layers 1-3, a circular mold 5 is pre-buried at the position of the expansion head of the designed pile end; the circular mold 5 is formed by connecting and combining two semicircular aluminum alloy plates 5-1 and 5-2 through bolts 5-3, the diameter of the circular mold 5 can be adjusted according to test requirements, and can be set to be 1.5 times, 2.0 times, 2.5 times and 3.0 times of the diameter of the model pile 1-6; the center of the model box 1 is provided with a model pile 1-6, the pile end of the model pile 1-6 is required to be positioned at the center of a space 1-7 reserved by a circular die 5, the diameter of the model pile 1-6 is 50mm, and the length of the model pile is 1000mm; the counterforce beam 3 is welded on the model box; the loading motor 4 is positioned above the model piles 1-6 and is fixed on the counter-force beam 3; the loading plate 2 is a square plate with a through hole in the center and is arranged on the sand layer 1-3, and the diameter of a central round hole of the loading plate 2 is the same as that of a through hole at the top of the round die 5; two rigid cushion blocks 2-1 are symmetrically distributed on two sides of a loading motor 4 above the loading plate 2, two jacks 2-2 are respectively arranged above the rigid cushion blocks 2-1, and the upper ends of the jacks 2-2 and the counter-force beams 3 are propped against each other to apply an overlying pressure to a sand layer; two rigid cushion blocks 2-1 are symmetrically distributed on two sides of a loading motor 4 above the loading plate 2, the air compressors 6 input air pressure into the slurry storage tank 7 through an air pipe 6-3, a pressure gauge 6-1 and a pressure regulating switch 6-2 are arranged on the air pipe, and the grouting pressure value can be controlled within the range of 0.5-3 MPa; the slurry storage tank 7 is internally provided with liquid cement soil which is uniformly stirred, and the slurry storage tank 7 is provided with a pressure release valve 7-1 and a pressure regulating switch 7-2 which are connected with a model box through a grouting pipe 7-4; the grouting pipe 7-4 is provided with a grouting valve 7-3, the end part of the grouting pipe is required to be buried into a space 1-7 reserved by the circular mold 5, and the liquid cement soil is required to be injected into the reserved space 1-7, and the volume of the liquid cement soil in the grouting tank 7 is required to be more than 1.5 times of the volume of the reserved space 1-7.
The working process of the invention is as follows: firstly, filling a sand layer 1-3 with a certain compactness in a model box 1, when the compactness of the sand layer is smaller in design requirement, preparing the sand layer 1-3 by adopting a sand rain method, obtaining the compactness of the soil body with the design requirement by controlling the drop distance between the bottom of a sand falling device and the surface of a test soil body, and when the compactness of the sand layer with the design requirement is larger, filling the sand layer by adopting a layering ramming method, and obtaining the compactness of the soil body with the design requirement by adopting a method of controlling the dry density and the volume of the sand layer; the method comprises the steps that in the filling process of a sand layer 1-3, a soil pressure sensor 1-4 and a pore water pressure sensor 1-5 are embedded in the sand layer, and the soil pressure of a pile end soil body and the grouting pressure in the sand layer and a pressure dissipation rule are measured respectively; in the sand layer filling process, a circular mold 5 is pre-buried at the position of the expansion head of the designed pile end; the center of the model box 1 is provided with a model pile 1-6, and the pile end is required to be positioned at the center of a space 1-7 reserved by the round die 5; injecting a cement soil sample into the reserved space 1-7 through a grouting pipe 7-4 by using an air compressor 6 and a grouting tank 7, taking out the circular mold 5 from the sand layer during grouting, and testing pore water pressure data at intervals during grouting and after grouting is finished; filling a sand layer with the thickness of 20cm after cement soil is maintained for 7 days, then arranging a loading plate 2 on the sand layer, arranging a rigid cushion block 2-1 and a jack 2-2 above the loading plate 2, and applying an overlying pressure to the sand layer by propping the upper end of the jack against a counterforce beam 3; after the cement soil sample is maintained for 28 days, a static load test is carried out on the model pile through the loading motor 4, the load and the displacement applied by the loading motor 4 can be automatically read and stored, and the soil pressure of the pile end soil body, the dissipation rule thereof and the pile end load displacement relative displacement relationship can be measured in the test.
Claims (6)
1. A test method for researching the bearing performance of an enlarged head of a pile end of a static drilling root planting pile is characterized by comprising the following steps: the test device based on the test of the pile end enlarged head bearing performance of the static drilling root planting pile is realized, the test device comprises a model box (1), a loading plate (2), a counter-force beam (3), a loading motor (4), a circular mold (5), an air compressor (6) and a slurry storage tank (7),
the model box (1) is formed by welding steel plates, I-steel (1-1) is welded on the side surface and the bottom of the model box to increase the rigidity of the model box, and a steel support (1-2) is welded on the bottom of the model box; the sand layer (1-3) is filled in the model box (1); a plurality of soil pressure sensors (1-4) and a plurality of pore water pressure sensors (1-5) are embedded in the sandy soil layer (1-3);
a circular mold (5) is embedded in the sandy soil layer (1-3); the circular mold (5) is a hollow cylinder and is formed by connecting and combining two semicircular aluminum alloy plates (5-1, 5-2) through bolts (5-3), and a reserved space (1-7) is formed in the circular mold; the center of the model box (1) is also provided with a model pile (1-6), the model pile (1-6) is hung on the counter-force beam (3), and the pile end of the model pile (1-6) is positioned at the center of a reserved space (1-7) in the circular die (5);
the loading plate (2) is a square plate with a through hole in the center and is arranged on the sand layer (1-3), and the model piles (1-6) penetrate through the through hole; two steel cushion blocks (2-1) are arranged above the loading plate (2), the steel cushion blocks (2-1) are symmetrically distributed on two sides of the loading motor (4), and a jack (2-2) is arranged above each steel cushion block (2-1);
the counterforce beam (3) is welded on the model box (1), and the counterforce beam (3) is propped against the upper end of the jack (2-2); the loading motor (4) is positioned above the model piles (1-6) and is fixed on the counter-force beam (3);
the slurry storage tank (7) is internally provided with liquid cement soil which is uniformly stirred, and the slurry storage tank (7) is provided with a pressure release valve (7-1), a pressure regulating switch (7-2) and a slurry injection pipe (7-4); the grouting pipe (7-4) is provided with a grouting valve (7-3), the end part of the grouting pipe (7-4) is required to be buried in the reserved space (1-7), and liquid cement soil is injected into the reserved space (1-7);
the air compressor (6) is provided with a through air pipe (6-3), a pressure gauge (6-1) and a pressure regulating switch (6-2) are arranged on the through air pipe, and the air pipe (6-3) is used for inputting air pressure into the pulp storage tank (7);
the jack (2-2) loads the sand layer (1-3) through the loading plate (2) to simulate different stress levels; the diameter of the model pile (1-6) is smaller than that of the circular mould (5);
the cement soil sample in the slurry storage tank (7) is uniformly stirred, the water content of the cement soil sample exceeds the liquid limit water content, and the cement soil sample is in a liquid state
The test method comprises the following steps:
filling sand in a model box (1), embedding a soil pressure sensor (1-4), a pore water pressure sensor (1-5) and a circular mold (5) in the filling process, embedding a grouting pipe (7-4) into a reserved space (1-7), placing a model pile (1-6) in the center of the model box (1), fixing the model pile (1-6) on a counter-force beam (3), enabling the pile end of the model pile (1-6) to be positioned in the center of the reserved space (1-7) in the circular mold (5), plugging the bottom of the model pile, and closing the top end of the circular mold (5); when the sand filling height is the same as the top of the circular mould (5), an air compressor (6) and a slurry storage tank (7) are arranged, liquid cement soil (7-5) which is uniformly stirred is filled in the slurry storage tank (7), the air compressor (6) is regulated to enable the slurry storage tank (7) to reach a designed grouting pressure value, the designed grouting pressure is maintained, grouting is started in the reserved space (1-7), and the circular mould (5) is slowly taken out from the sand while grouting, so that the liquid cement soil slurry fills the reserved space (1-7) of the circular mould (5) to form a pile end expansion head; filling a sand layer with the thickness of 20-50cm on the top of the sand layer after grouting is finished for 7-28 days, covering the upper surface of the filled sand layer (1-3) with a loading plate (2), and applying an overlay pressure to the sand layer through a jack (2-2) to enable the applied overlay pressure value to reach a design pressure value and maintain stability; and loading the model pile by a loading motor (4) after grouting is completed for 28-90 days.
2. The test method for researching the bearing performance of the enlarged footing of the pile end of the static drilling root planting pile according to claim 1, wherein the ratio of the side length of the model box (1) to the diameter of the circular mould (5) is not less than 10.
3. The test method for researching the bearing performance of the enlarged footing of the static drill root pile tip according to claim 1, wherein the ratio of the distance between the bottom of the circular mold (5) and the bottom of the model box (1) to the diameter of the circular mold (5) is not less than 10.
4. The test method for researching the bearing performance of the enlarged footing of the pile end of the static drilling root planting pile according to claim 1, wherein the limit loading value of the loading motor (4) is 200kN, and the stroke is 100mm.
5. The test method for researching the bearing performance of the enlarged footing of the pile end of the static drilling root planting pile according to claim 1, wherein the diameter of the central round hole of the loading plate (2) is the same as the diameter of the model pile (1-6).
6. The test method for researching the bearing performance of the enlarged head of the pile end of the static drilling root planting pile according to claim 1, wherein the side wall of the slurry storage tank (7) is made of transparent organic glass, and the side wall is marked with volume scales.
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| CN111622273B (en) * | 2020-05-08 | 2021-04-23 | 浙江大学 | Test device and test method for simulating pile foundation bearing performance of precast pile filled with discrete drainage materials around |
| CN111622277B (en) * | 2020-06-01 | 2021-05-07 | 浙江大学 | Test device and test method for simulating influence of pile end cavities on bearing performance of pile foundation |
| CN112982509B (en) * | 2021-02-24 | 2021-11-26 | 浙江大学 | Construction method of pre-stressed anchor cable axial force transmission rule mathematical model in composite stratum based on field drawing test |
| CN113356228B (en) * | 2021-06-18 | 2022-04-29 | 武汉理工大学 | Mixing test device for foundation pit supporting structure simulation |
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