CN210507566U - Test device for bearing capacity test of stiff composite pile - Google Patents
Test device for bearing capacity test of stiff composite pile Download PDFInfo
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- CN210507566U CN210507566U CN201921325589.7U CN201921325589U CN210507566U CN 210507566 U CN210507566 U CN 210507566U CN 201921325589 U CN201921325589 U CN 201921325589U CN 210507566 U CN210507566 U CN 210507566U
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Abstract
The utility model discloses a test device for bearing capacity test of a stiff composite pile, which belongs to the technical field of test in foundation engineering and comprises a backing ring, a cushion block, a high-strength inner core, a cement soil outer core, a press machine, a displacement meter, a data storage system and a data wire; the displacement meter is connected with the data storage system through a data line, and the press machine is connected with the data storage system through a data line. The press machine comprises a loading system and a press machine support, wherein the press machine support comprises a support bottom plate and an upper supporting frame, the support bottom plate is of a circular structure, and the diameter of the simulated soil layer is more than or equal to 3 times of the diameter of the cement soil outer core. The utility model discloses under the condition of indoor test, the on-the-spot condition of composite pile has been simulated to a very big degree to the stress mode of analysis composite pile on the basis of predecessor's research, the destruction mode of composite pile is researched out to the pertinence adoption loading mode, provides data support for the theory of strength nature composite pile.
Description
Technical Field
The utility model belongs to the technical field of test in the foundation engineering, concretely relates to test device of strength nature composite pile bearing capacity test.
Background
The stiff composite pile is a new composite pile type which is stressed together by inserting the core pile into the cement-soil mixing pile before the initial setting of the cement-soil mixing pile. Therefore, pile side friction resistance is inevitably generated between the inner core and the outer core, and between the outer core and the soil body around the pile, the pile side friction resistance is measured mainly by a side resistance characteristic value, and the ultimate load force born by a unit pile body is the standard value obtained by dividing the maximum static load test pressure by the safety factor of 2.0. The existing and commonly used pile body side resistance test technology is more traditional, and the conventional method pile body side resistance test method is divided into two methods.
One method for testing the pile load in site engineering is to embed a steel bar stress meter in the pile body, load a vertical load or a horizontal load on the pile top, measure the axial stress of the pile body, the deformation of the pile top and the load, and indirectly obtain the lateral resistance of the pile body through calculation and analysis. The most obvious defect of the method is that the side resistance of the pile body is obtained through the difference and analysis of the axial force of the pile body and the load of the pile top, the side resistance of the pile body of the pile soil contact surface cannot be directly measured, the error of the analysis result and the actual side resistance exertion rule of the pile body can be caused by the assumption in the calculation, and the action rule of the side resistance of the pile body cannot be truly reflected.
The other method for testing the pile body side resistance is a direct shear test of the pile soil contact surface in the laboratory, the method can accurately and precisely perform the test and monitor the change of the side resistance, but the experimental conclusion has errors due to the fact that the pile soil contact surface in the laboratory is not in line with the engineering field.
Therefore, it is necessary to improve the design of the existing test method, otherwise the theoretical development of the stiff composite pile is bound to be limited. Based on this, the utility model provides a test device of compound stake bearing capacity test of strength nature.
Disclosure of Invention
To the above-mentioned technical problem who exists among the prior art, the utility model provides a test device of strength nature composite pile bearing capacity test has overcome the not enough of prior art. Under the condition of indoor tests, the field condition of the composite pile is simulated to a great extent, the stress mode of the composite pile is analyzed on the basis of the previous research, the loading mode is adopted in a targeted manner, the damage mode of the composite pile is researched, and data support is provided for the theory of the stiff composite pile.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
the utility model provides a test device of compound stake bearing capacity test of strength nature which characterized in that: the device comprises a backing ring, a cushion block, a high-strength inner core, a cement soil outer core, a simulation soil layer, a press machine, a displacement meter, a data storage system and a data line; the displacement meter is connected with a data storage system through a data line, and the press machine is connected with the data storage system through the data line;
the press machine comprises a loading system and a press machine support, wherein the press machine support comprises a support bottom plate and an upper supporting frame, the support bottom plate is of a circular structure, the support bottom plate is made of cast iron, the Rockwell hardness of the support bottom plate is 50-60HRC, the upper supporting frame is made of high-hardness alloy, and the bending strength of the upper supporting frame is greater than 300kN/mm2；
The diameter of the simulated soil layer is more than or equal to 3 times of the diameter of the outer core of the cement soil, the type of the simulated soil layer is layered soft soil or medium hard soil, and the N value of the standard penetration test impact number of the simulated soil layer is not more than 80.
Preferably, the backing ring is made of cast iron, the Rockwell hardness is 40-50HRC, the outer diameter of the backing ring is larger than or equal to the diameter of a simulated soil layer, the inner diameter of the backing ring is larger than or equal to the diameter of the high-strength inner core, the part of the inner diameter of the backing ring, which is larger than the diameter of the high-strength inner core, does not exceed half of the difference between the diameter of the cement soil outer core and the diameter of the high-strength inner core, and the height of the backing ring is 5-10 cm.
Preferably, the cushion block is made of cast iron, the Rockwell hardness is 40-50HRC, the diameter of the cushion block is smaller than or equal to the diameter of the high-strength inner core, the part, smaller than the diameter of the high-strength inner core, of the cushion block is not more than one eighth of the diameter of the high-strength inner core, and the height of the cushion block is 5-10 cm.
Preferably, the material of high strength inner core is concrete, and the concrete strength grade is not less than C50.
Preferably, the cement soil outer core is made of ordinary portland cement, a soil body, an expanding agent and water, wherein the content of the ordinary portland cement accounts for 10% -20% of the volume of the whole stiff composite pile, the doping amount of the expanding agent is 0% -10% of the doping amount of the cement, the doping amount of the water is 5% -20% of the volume of the whole stiff composite pile, and the unconfined compressive strength of the cement soil is greater than or equal to 10 MPa.
Preferably, the displacement meters are arranged in two groups, each group comprises two displacement meters, the first group is arranged on a square rigid steel sheet tightly attached to the cushion block, and the two displacement meters are symmetrically distributed around the center point of the cushion block; the second group is arranged on a square rigid steel sheet tightly attached to the cement soil outer core, the two displacement meters are symmetrically distributed about the central point of the cement soil outer core, the thickness of the rigid steel sheet is 1-3mm, the side length of the rigid steel sheet is 3-5cm, the precision of the displacement meters is 0.001mm, and the measuring range is not less than 100 mm.
Preferably, the type of the simulated soil layer can be layered single mucky soil, artificial filling soil, clay powder, red clay, fine sand powder, coarse medium sand or a combination of a plurality of soil bodies.
The utility model discloses the beneficial technological effect who brings:
(1) the utility model discloses a vertical side resistance of pile body can be surveyed to the test device, has realized the experimental test of on-the-spot pile side resistance, has overcome the error that traditional on-the-spot load test method's indirect calculation derived pile body side resistance and the unreal test result of laboratory configuration stake soil contact surface sample. (2) The vertical load loading system adopts high-strength telescopic shaft force rod loading, the method of respectively controlling the size of the shaft force through the shaft force loading unit can achieve the purpose of applying micro vertical shaft force increment steps and finely adjusting the vertical load in real time, and meanwhile, the plurality of displacement meters can monitor vertical settlement in real time and reflect the degree of exertion of the vertical side resistance of the pile. (3) The utility model discloses an effect is that the device simple structure, convenient to use, easily transport, repeatedly usable need not actually try the stake, and the cost is few, and the expense is low, and efficiency is more high, can simulate foundation soil and at the actual atress deformation situation under the foundation pile effect, can provide the relevant parameter of stake resistance before foundation pile design construction to supplementary shear modulus, the compression modulus isoparametric that provides foundation soil.
Drawings
Fig. 1 is the structural schematic diagram of the stiffness composite pile lateral resistance testing device of the utility model.
Fig. 2 is the structure schematic diagram of the pressure machine in the stiffness composite pile side resistance testing device of the utility model.
Wherein, 1-backing ring; 2-cushion block; 3-high strength inner core; 4-a cement soil outer core; 5-simulating a soil layer; 6-a press machine; 7-a displacement meter; 8-a data storage system; 9-a data line; 10-a loading system; 11-press frame.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments:
example 1:
application the utility model relates to a strength nature composite pile side resistance test equipment is experimental, and the size of each part of model stake is: the diameter of the concrete inner core is 200mm, the height of the concrete inner core is 500mm, the diameter of the cement outer core is 500mm, and the height of the cement outer core is 500 mm.
As shown in fig. 1-2, a test device for bearing capacity test of a stiff composite pile is characterized in that: the device comprises a backing ring 1, a cushion block 2, a high-strength inner core 3, a cement soil outer core 4, a simulation soil layer 5, a press machine 6, a displacement meter 7, a data storage system 8 and a data line 9; the displacement meter is connected with a data storage system 8 through a data line 9, and the press machine 6 is connected with the data storage system 8 through the data line 9;
the press machine 6 comprises a loading system 10 and a press machine support 11, wherein the press machine support 11 comprises a support base plate and an upper supporting frame, the support base plate is of a circular structure and is made of cast iron, the Rockwell hardness of the support base plate is 50HRC, the upper supporting frame is made of high-hardness alloy, and the bending strength of the upper supporting frame is 300kN/mm2；
The diameter of the simulated soil layer 5 is equal to 3 times of the diameter of the cement soil outer core 4, the type of the simulated soil layer 5 is layered soft soil, and the N value of the standard penetration test impact number of the simulated soil layer 5 is 40.
Preferably, the backing ring 1 is made of cast iron, the Rockwell hardness is 40HRC, the outer diameter of the backing ring 1 is larger than or equal to the diameter of the simulated soil layer 5, the inner diameter of the backing ring 1 is larger than or equal to the diameter of the high-strength inner core 3, the part of the inner diameter of the backing ring 1, which is larger than the diameter of the high-strength inner core 3, does not exceed half of the difference between the diameter of the cement soil outer core 4 and the diameter of the high-strength inner core 3, and the height of the backing ring 1 is 5 cm.
Preferably, the cushion block 2 is made of cast iron, the Rockwell hardness is 40HRC, the diameter of the cushion block 2 is equal to that of the high-strength inner core 3, and the height of the cushion block 2 is 5 cm.
Preferably, the high-strength inner core 3 is made of concrete, and the strength grade of the concrete is not less than C50.
Preferably, the cement soil outer core 4 is composed of ordinary portland cement, a soil body, an expanding agent and water, wherein the content of the ordinary portland cement accounts for 12% of the volume of the whole stiff composite pile, the doping amount of the expanding agent is 0.5% of the doping amount of the cement, the doping amount of the water is 10% of the volume of the whole stiff composite pile, and the unconfined compressive strength of the cement soil is equal to 10 MPa.
Preferably, the displacement meters 7 are arranged in two groups, each group comprises two displacement meters 7, the first group is arranged on a square rigid steel sheet tightly attached to the cushion block 2, and the two displacement meters 7 are symmetrically distributed about the central point of the cushion block 2; the second group is arranged on a square rigid steel sheet tightly attached to the cement soil outer core 4, the two displacement meters 7 are symmetrically distributed about the central point of the cement soil outer core 4, the thickness of the rigid steel sheet is 1mm, the side length of the rigid steel sheet is 3cm, the precision of the displacement meters 7 is 0.001mm, and the measuring range is not less than 100 mm.
Preferably, the kind of the simulated soil layer 5 is a layered single mucky soil.
Example 2:
application the utility model relates to a strength nature composite pile side resistance test equipment is experimental, and the size of each part of model stake is: the diameter of the concrete inner core is 250mm, the height of the concrete inner core is 500mm, the diameter of the cement outer core is 500mm, and the height of the cement outer core is 500 mm.
As shown in fig. 1-2, a test device for bearing capacity test of a stiff composite pile is characterized in that: the device comprises a backing ring 1, a cushion block 2, a high-strength inner core 3, a cement soil outer core 4, a simulation soil layer 5, a press machine 6, a displacement meter 7, a data storage system 8 and a data line 9; the displacement meter is connected with a data storage system 8 through a data line 9, and the press machine 6 is connected with the data storage system 8 through the data line 9;
the press machine 6 comprises a loading system 10 and a press machine support 11, wherein the press machine support 11 comprises a support base plate and an upper supporting frame, the support base plate is of a circular structure and is made of cast iron, the Rockwell hardness of the support base plate is 50HRC, the upper supporting frame is made of high-hardness alloy, and the bending strength of the upper supporting frame is 350kN/mm2；
The diameter of the simulated soil layer 5 is equal to 4 times of the diameter of the cement soil outer core 4, the type of the simulated soil layer 5 is selected from layered medium-hard soil, and the N value of the standard penetration test impact number of the simulated soil layer 5 is 60.
Preferably, the backing ring 1 is made of cast iron, the Rockwell hardness is 50HRC, the outer diameter of the backing ring 1 is equal to the diameter of the simulated soil layer 5, the inner diameter of the backing ring 1 is equal to the diameter of the high-strength inner core 3, and the height of the backing ring 1 is 7 cm.
Preferably, the cushion block 2 is made of cast iron, the rockwell hardness is 50HRC, the diameter of the cushion block 2 is smaller than that of the high-strength inner core 3, the part of the cushion block 2, the diameter of which is smaller than that of the high-strength inner core 3, is one sixteenth of the diameter of the high-strength inner core 3, and the height of the cushion block 2 is 5 cm.
Preferably, the high-strength inner core 3 is made of concrete, and the strength grade of the concrete is C60.
Preferably, the cement soil outer core 4 is composed of ordinary portland cement, a soil body, an expanding agent and water, wherein the content of the ordinary portland cement accounts for 15% of the volume of the whole stiff composite pile, the doping amount of the expanding agent is 1% of the doping amount of the cement, the doping amount of the water is 12% of the volume of the whole stiff composite pile, and the unconfined compressive strength of the cement soil is equal to 10 MPa.
Preferably, the displacement meters 7 are arranged in two groups, each group comprises two displacement meters 7, the first group is arranged on a square rigid steel sheet tightly attached to the cushion block 2, and the two displacement meters 7 are symmetrically distributed about the central point of the cushion block 2; the second group is arranged on a square rigid steel sheet tightly attached to the cement soil outer core 4, the two displacement meters 7 are symmetrically distributed about the central point of the cement soil outer core 4, the thickness of the rigid steel sheet is 1mm, the side length of the rigid steel sheet is 3cm, the precision of the displacement meters 7 is 0.001mm, and the measuring range is not less than 100 mm.
Preferably, the type of the simulated soil layer 5 is layered coarse medium sand.
The utility model relates to a test device of compound stake bearing capacity test of strength nature under the condition of indoor test, the site conditions of compound stake has been simulated to the very big degree to the atress mode of compound stake of analysis on the basis of predecessor's research, the destruction mode of compound stake is researched out to the corresponding adoption loading mode, provides data support for the theory of the compound stake of strength nature.
Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and the changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention also belong to the protection scope of the present invention.
Claims (6)
1. The utility model provides a test device of compound stake bearing capacity test of strength nature which characterized in that: the device comprises a backing ring, a cushion block, a high-strength inner core, a cement soil outer core, a simulation soil layer, a press machine, a displacement meter, a data storage system and a data line; the displacement meter is connected with a data storage system through a data line, and the press machine is connected with the data storage system through the data line;
the press machine comprises a loading system and a press machine support, wherein the press machine support comprises a support bottom plate and an upper supporting frame, the support bottom plate is of a circular structure, the support bottom plate is made of cast iron, the Rockwell hardness of the support bottom plate is 50-60HRC, the upper supporting frame is made of high-hardness alloy, and the bending strength of the upper supporting frame is greater than 300kN/mm2；
The diameter of the simulated soil layer is more than or equal to 3 times of the diameter of the outer core of the cement soil, the type of the simulated soil layer is layered soft soil or medium hard soil, and the N value of the standard penetration test impact number of the simulated soil layer is not more than 80.
2. The test device for the bearing capacity test of the stiff composite pile according to claim 1, wherein the backing ring is made of cast iron, the Rockwell hardness is 40-50HRC, the outer diameter of the backing ring is larger than or equal to the diameter of a simulated soil layer, the inner diameter of the backing ring is larger than or equal to the diameter of the high-strength inner core, the part of the inner diameter of the backing ring, which is larger than the diameter of the high-strength inner core, is not more than half of the difference between the diameter of the cement soil outer core and the diameter of the high-strength inner core, and the height of the backing ring is 5-10 cm.
3. The test device for the bearing capacity test of the stiff composite pile according to claim 1, wherein the cushion block is made of cast iron, the Rockwell hardness is 40-50HRC, the diameter of the cushion block is smaller than or equal to the diameter of the high-strength inner core, the part of the cushion block, the diameter of which is smaller than the diameter of the high-strength inner core, is not more than one eighth of the diameter of the high-strength inner core, and the height of the cushion block is 5-10 cm.
4. The test device for testing the bearing capacity of the stiff composite pile according to claim 1, wherein the high-strength inner core is made of concrete, and the strength grade of the concrete is not less than C50.
5. The test device for the bearing capacity test of the stiff composite pile according to claim 1, wherein the displacement meters are two groups, two in each group, the first group is arranged on a square rigid steel sheet tightly attached to the cushion block, and the two displacement meters are symmetrically distributed about the center point of the cushion block; the second group is arranged on a square rigid steel sheet tightly attached to the cement soil outer core, the two displacement meters are symmetrically distributed about the central point of the cement soil outer core, the thickness of the rigid steel sheet is 1-3mm, the side length of the rigid steel sheet is 3-5cm, the precision of the displacement meters is 0.001mm, and the measuring range is not less than 100 mm.
6. The test device for testing bearing capacity of a stiff composite pile according to claim 1, wherein the type of the simulated soil layer can be layered single mucky soil, artificial filling, silty clay, red clay, silty fine sand, coarse medium sand or a combination of multiple soil bodies.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110344456A (en) * | 2019-08-15 | 2019-10-18 | 北京中岩大地科技股份有限公司 | A kind of experimental rig and its application method of stiff composite pile test of bearing capacity |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110344456A (en) * | 2019-08-15 | 2019-10-18 | 北京中岩大地科技股份有限公司 | A kind of experimental rig and its application method of stiff composite pile test of bearing capacity |
| CN110344456B (en) * | 2019-08-15 | 2024-08-09 | 北京中岩大地科技股份有限公司 | Test device for testing bearing capacity of stiff composite pile and application method of test device |
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