CN220978134U - Negative frictional resistance detection test device for pile foundation in collapsible loess - Google Patents
Negative frictional resistance detection test device for pile foundation in collapsible loess Download PDFInfo
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- CN220978134U CN220978134U CN202322716308.3U CN202322716308U CN220978134U CN 220978134 U CN220978134 U CN 220978134U CN 202322716308 U CN202322716308 U CN 202322716308U CN 220978134 U CN220978134 U CN 220978134U
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- 238000012360 testing method Methods 0.000 title claims abstract description 65
- 238000001514 detection method Methods 0.000 title claims abstract description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 89
- 239000002689 soil Substances 0.000 claims abstract description 49
- 238000002474 experimental method Methods 0.000 claims abstract description 25
- 238000001914 filtration Methods 0.000 claims abstract description 18
- 238000005259 measurement Methods 0.000 description 13
- 230000008859 change Effects 0.000 description 6
- 238000004062 sedimentation Methods 0.000 description 4
- 238000004088 simulation Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000007596 consolidation process Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
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- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
The utility model provides a negative frictional resistance detection test device for pile foundations in collapsible loess, which belongs to the technical field of collapsible loess and comprises an experiment box, wherein a yellow soil layer and a water filtering layer are sequentially and horizontally arranged in the experiment box from top to bottom, a plurality of test piles are vertically inserted on the yellow soil layer, stress strain sensors are arranged on the test piles, the lower ends of the test piles are fixed in the yellow soil layer, a water inlet pipe is arranged at the position of the left side of the experiment box, which is positioned below the test piles. Meanwhile, the transitional settlement of the building is prevented, and the safety of the building is improved.
Description
Technical Field
The utility model belongs to the technical field of collapsible loess, and particularly relates to a negative friction resistance detection test device for pile foundations in collapsible loess.
Background
The pile foundation is laid in the soil body, the upper load acts on the pile end pile soil to generate relative displacement under the general condition, the sedimentation rate of the pile surrounding soil is far smaller than the sedimentation rate of the pile, the side friction resistance born by the pile is upward, namely the pile side friction resistance, however, under certain special conditions, the sedimentation rate of the pile surrounding soil is far greater than the sedimentation rate of the pile, the side friction resistance born by the pile is downward, namely the negative friction resistance, and the negative friction resistance has a serious weakening effect on the pile foundation, and particularly in the collapsible loess area.
The collapsible loess is widely distributed in China, is mainly distributed in most areas of Shanxi, shaanxi and Gansu and in the southwest of yellow river, and is found in most areas of Ningxia, qinghai and Hebei, and has low humidity and high porosity in parts of Xinjiang, shandong, liaoning and the like, and has higher general strength and smaller compressibility when not soaked by water, but after soaked by water, the soil structure can be quickly damaged, larger additional sinking is generated, the strength is quickly reduced, and the pile body damage, uneven sinking of the pile foundation and the like can be caused by the downward drag force generated by the negative frictional resistance of the pile side in pile foundation engineering, so that the safety of a building is seriously influenced.
At present, lack the device that can detect pile foundation negative friction resistance and produce the resistance change in collapsible loess on the market for the workman is not just under construction through the experiment in collapsible loess region, leads to pile foundation overlength easily, causes the problem of material waste, not environmental protection, and blindly reduces the stake length, leads to the condition that the transition subsides appears in the building easily, causes the potential safety hazard, consequently, needs a negative friction resistance detection test device of pile foundation in the collapsible loess to solve this problem.
Disclosure of utility model
The utility model aims to provide a negative frictional resistance detection test device for pile foundations in collapsible loess.
In order to achieve the above purpose, the utility model provides a negative frictional resistance detection test device for pile foundations in collapsible loess, which comprises an experiment box, wherein a loess layer and a water filtering layer are sequentially and horizontally arranged in the experiment box from top to bottom, a plurality of test piles are vertically inserted on the loess layer, stress strain sensors are arranged on the test piles, the lower ends of the test piles are fixed in the loess layer, a water inlet pipe is arranged at the left side of the experiment box and positioned below the test piles, and the water inlet pipe is positioned at the position of the loess layer.
Further, the middle lower part in loess intralamellar is equipped with the raceway, raceway one end with the inlet tube intercommunication, and the other end seals the setting, the raceway is located test stake below, evenly offered a plurality of apopores on the lateral wall of raceway.
Furthermore, the water delivery pipe is uniformly paved in the loess layer in an S shape.
Further, a water outlet pipe is arranged at the right side of the experiment box at the water filtering layer.
Further, the left and right inner bottom walls of the experimental box are arranged in a low-inclination mode, and the upper surface of the water filtering layer is kept horizontal.
Further, the right side fixedly connected with vertical bracing piece of experimental box upper surface, the bracing piece upper end rotates and is connected with horizontal telescopic link, the telescopic link is kept away from the bottom of bracing piece one end is equipped with distance sensor.
Further, a plurality of test piles are sequentially arranged according to plum blossom shapes.
Further, the distance between the adjacent test piles is 1.5-2 meters.
The utility model has the advantages that:
1. According to the utility model, through experimental data acquisition and numerical simulation, the resistance change condition and rule of the negative frictional resistance of the test pile in collapsible loess are summarized, so that the designed pile length is reasonably reduced by reducing the pile side frictional resistance when the pile foundation is constructed in a severe collapsible loess area, the consumption of pile body steel bars and concrete is effectively reduced, materials are saved, meanwhile, the transitional settlement of a building is prevented, and the safety of the building is improved.
2. The device can test single piles and group piles, can realize the change rule of the negative friction resistance of pile bodies of the group piles in the collapsible loess consolidation process of uneven load on the group piles, and is used for guiding the actual engineering according to the change rule in the actual engineering.
3. The utility model has simple structure and low test operation difficulty.
The utility model will now be described in detail with reference to the drawings and examples.
Drawings
Fig. 1 is a schematic diagram of the structure of the present utility model.
Fig. 2 is a top view of the structure of the present utility model.
Fig. 3 is a cross-sectional view of a depression structure of the present utility model.
FIG. 4 is a flow chart showing a collapsible loess settlement test according to the present utility model.
Reference numerals illustrate: 1. an experiment box; 2. a layer of yellow soil; 3. a water filtering layer; 4. testing piles; 5. a stress-strain sensor; 6. a water inlet pipe; 7. a water pipe; 8. a water outlet hole; 9. a water outlet pipe; 10. a support rod; 11. a telescopic rod; 12. a distance sensor.
Detailed Description
The following detailed description, structural features and functions of the present utility model are provided with reference to the accompanying drawings and examples in order to further illustrate the technical means and effects of the present utility model to achieve the predetermined objects.
The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
In the description of the present utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "aligned," "overlapping," "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 description of the present utility model 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 operate in a specific orientation, and therefore should not be construed as limiting the present utility model.
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 or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second" may include one or more such features, either explicitly or implicitly; in the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.
Example 1
The embodiment provides a negative frictional resistance detection test device of pile foundation in collapsible loess as shown in fig. 1-4, which comprises an experiment box 1, wherein a yellow soil layer 2 and a water filtering layer 3 are sequentially and horizontally arranged in the experiment box 1 from top to bottom, a plurality of test piles 4 are vertically inserted on the yellow soil layer 2, stress strain sensors 5 are arranged on the test piles 4, the lower ends of the test piles 4 are fixed in the yellow soil layer 2, a water inlet pipe 6 is arranged at the left side of the experiment box 1 and positioned at the yellow soil layer 2, and the water inlet pipe 6 is positioned below the test piles 4.
Further, the middle lower part in the yellow soil layer 2 is provided with a water pipe 7, one end of the water pipe 7 is communicated with the water inlet pipe 6, the other end of the water pipe 7 is closed, the water pipe 7 is positioned below the test pile 4, and a plurality of water outlet holes 8 are uniformly formed in the outer side wall of the water pipe 7.
Further, the water pipe 7 is uniformly laid in the yellow soil layer 2 in an S shape.
Further, a water outlet pipe 9 is arranged at the right side of the experiment box 1 and positioned at the water filtering layer 3.
Further, the inner bottom wall of the experiment box 1 is arranged in a low-right and high-left inclined manner, and the upper surface of the water filtering layer 3 is kept horizontal.
Further, the right side fixedly connected with vertical bracing piece 10 of experimental box 1 upper surface, bracing piece 10 upper end rotation is connected with horizontal telescopic link 11, and the bottom that bracing piece 10 one end was kept away from to telescopic link 11 is equipped with distance sensor 12.
Further, the test piles 4 are sequentially arranged according to the quincuncial shape.
Further, the distance between the adjacent test piles 4 is 1.5-2 m.
A negative friction resistance detection test method for pile foundations in collapsible loess comprises the following steps:
S1: firstly arranging a yellow soil layer 2 and a water filtering layer 3 in an experiment box 1, pre-burying and installing a water conveying pipe 7 at the middle lower part of the yellow soil layer 2, paving the water conveying pipe 7 to be S-shaped, communicating one end of an opening of the water conveying pipe 7 with a water inlet pipe 6 on the experiment box 1, sequentially inserting a plurality of test piles 4 on the yellow soil layer 2 according to a quincuncial shape, and constructing a test site for completing negative friction resistance detection of the test piles 4 in collapsible loess settlement, wherein the interval between adjacent test piles 4 is 1.5-2 meters;
S2: in the experiment, the distance measurement and recording are carried out at a height position above the yellow soil layer 2 through the distance sensor 12, then a water valve at the water inlet pipe 6 is opened, so that water flows into the water pipe 7 through the water inlet pipe 6, uniformly flows out of the water pipe 7 into the yellow soil layer 2 through the water outlet holes 8, the yellow soil layer 2 is sunk downwards after absorbing the water flowing out of the water pipe 7, and the stress caused by the sinking and settlement of the yellow soil layer 2 on the test pile 4 is taken as an input signal by the stress strain sensor 5 on the test pile 4 and is converted into an output signal to be transmitted to a computer system for recording;
s3: when the water quantity flowing out of the water pipe 7 is excessive, the excessive water flows downwards into the water filtering layer 3 and then flows out through the water outlet pipe 9 at the water filtering layer 3, wherein the left and right sides of the inner bottom wall of the experiment box 1 are obliquely arranged, so that the excessive water at the water filtering layer 3 quickly flows to the water outlet pipe 9 and flows out through the water outlet pipe 9;
S4: when the yellow soil layer 2 is settled, measuring the subsidence distance of the yellow soil layer 2 at the position of the same horizontal height by the distance sensor 12, then transmitting the measured distance to a computer system for recording, and after the measurement is finished, recording the subsidence distance of the yellow soil layer 2 by using the first measured distance-the second measured distance = the subsidence distance of the yellow soil layer 2, wherein the distance measurement of the subsidence of the yellow soil layer 2 at the same horizontal height for a plurality of times can be performed on the yellow soil layer 2 by controlling the telescopic rod 11 to telescopic and rotating the telescopic rod 11 and the supporting rod 10, so that the measured data is more accurate;
s5: after the measurement data in the stress strain sensor 5 and the measurement data in the distance sensor 12 are measured and recorded in a computer system, the real-time collected data are simulated through a computer algorithm, and then the simulation test of the negative friction resistance detection of the test pile 4 in collapsible loess settlement is completed.
The working process comprises the following steps:
Before an experiment is carried out, a test site for detecting collapsible loess settlement is firstly constructed, a yellow soil layer 2 and a water filtering layer 3 are arranged in an experiment box 1, a water pipe 7 is pre-buried and installed at the middle lower part of the yellow soil layer 2, the water pipe 7 is paved in an S shape, one end of an opening of the water pipe 7 is communicated with a water inlet pipe 6 on the experiment box 1, a plurality of test piles 4 are sequentially inserted into the yellow soil layer 2 according to a quincuncial shape, the interval between every two adjacent test piles 4 is 1.5-2 meters, and the test site for detecting the negative friction resistance of the test piles 4 in the collapsible loess settlement can be constructed;
in the experiment, the distance measurement and recording are carried out at a height position above the yellow soil layer 2 through the distance sensor 12, then a water valve at the water inlet pipe 6 is opened, so that water flows into the water pipe 7 through the water inlet pipe 6, uniformly flows out of the water pipe 7 into the yellow soil layer 2 through the water outlet holes 8, the yellow soil layer 2 is sunk downwards after absorbing the water flowing out of the water pipe 7, and the stress caused by the sinking and settlement of the yellow soil layer 2 on the test pile 4 is taken as an input signal by the stress strain sensor 5 on the test pile 4 and is converted into an output signal to be transmitted to a computer system for recording; when the water quantity flowing out of the water pipe 7 is excessive, the excessive water flows downwards into the water filtering layer 3 and then flows out through the water outlet pipe 9 at the water filtering layer 3, wherein the left and right sides of the inner bottom wall of the experiment box 1 are obliquely arranged, so that the excessive water at the water filtering layer 3 quickly flows to the water outlet pipe 9 and flows out through the water outlet pipe 9;
After the yellow soil layer 2 is settled, measuring the subsidence distance of the yellow soil layer 2 at the position with the same horizontal height as the first measurement by the distance sensor 12, then transmitting the measured distance to a computer system for recording, and after the measurement is completed, recording the subsidence distance of the yellow soil layer 2 by using the first measured distance-the second measured distance = the subsidence distance of the yellow soil layer 2, wherein the distance measurement of the subsidence of the yellow soil layer 2 at the plurality of different positions of the yellow soil layer 2 can be carried out on the yellow soil layer 2 by the telescopic rod 11, and further, the distance sensor 12 can be transferred to one side far away from the test pile 4 by rotating the telescopic rod 11 when the distance sensor 12 is not needed to be used, and meanwhile, the distance sensor 12 can be respectively used for measuring the distance at different positions with the same horizontal height in the two times, and the distance sensor 12 can be used for carrying out telescopic measurement on the yellow soil layer 2 by itself, so that the subsidence distance measurement of the yellow soil layer 2 at different positions of the same horizontal height can be further enlarged, and the distance sensor 12 can be used for measuring the distance sensor 12 more accurately;
after the measurement data in the stress strain sensor 5 and the measurement data in the distance sensor 12 are measured and recorded in a computer system, the data acquired in real time are simulated through a computer algorithm, and the resistance change value generated by the negative frictional resistance of the pile foundation in collapsible loess is calculated, so that the simulation test of the negative frictional resistance detection of the test pile 4 in collapsible loess settlement is completed.
In summary, the utility model combines the experimental data acquisition and numerical simulation to summarize the resistance change condition and rule of the negative friction resistance of the test pile 4 in collapsible loess, so that the pile foundation of the type is reasonably reduced in design pile length by reducing pile side friction resistance when being constructed in severe collapsible loess areas, thereby effectively reducing the consumption of pile body steel bars and concrete, saving materials, simultaneously avoiding the condition of transitional settlement of a building caused by blindly reducing pile length, and improving the safety of the building.
The foregoing is a further detailed description of the utility model in connection with the preferred embodiments, and it is not intended that the utility model be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the utility model, and these should be considered to be within the scope of the utility model.
Claims (8)
1. Negative friction resistance detection test device of pile foundation in collapsible loess, its characterized in that: including experimental box (1), be equipped with yellow soil layer (2) and drainage layer (3) from last decurrent level in experimental box (1), vertical inserting is equipped with a plurality of test piles (4) on yellow soil layer (2), be equipped with stress strain sensor (5) on test pile (4), the lower extreme of test pile (4) is fixed in yellow soil layer (2), the left side of experimental box (1) is located yellow soil layer (2) department is equipped with inlet tube (6), inlet tube (6) are located test pile (4) below.
2. The negative frictional resistance detection test device for pile foundations in collapsible loess as set forth in claim 1, wherein: the middle lower part in the loess layer (2) is provided with a water delivery pipe (7), one end of the water delivery pipe (7) is communicated with the water inlet pipe (6), the other end of the water delivery pipe is closed, the water delivery pipe (7) is positioned below the test pile (4), and a plurality of water outlet holes (8) are uniformly formed in the outer side wall of the water delivery pipe (7).
3. The negative frictional resistance detection test device for pile foundations in collapsible loess as set forth in claim 2, wherein: the water delivery pipe (7) is uniformly paved in the yellow soil layer (2) in an S shape.
4. The negative frictional resistance detection test device for pile foundations in collapsible loess as set forth in claim 1, wherein: the right side of the experiment box (1) is provided with a water outlet pipe (9) at the position of the water filtering layer (3).
5. The negative frictional resistance detection test device for pile foundation in collapsible loess as set forth in claim 4, wherein: the left and right sides of the inner bottom wall of the experiment box (1) are arranged in a low-inclination mode, and the upper surface of the water filtering layer (3) is kept horizontal.
6. The negative frictional resistance detection test device for pile foundations in collapsible loess as set forth in claim 1, wherein: the right side fixedly connected with vertical bracing piece (10) of experimental box (1) upper surface, bracing piece (10) upper end rotates and is connected with horizontal telescopic link (11), telescopic link (11) are kept away from the bottom of bracing piece (10) one end is equipped with distance sensor (12).
7. The negative frictional resistance detection test device for pile foundation in collapsible loess as set forth in claim 4, wherein: the test piles (4) are sequentially arranged according to a quincuncial shape.
8. The negative frictional resistance detection test device for pile foundation in collapsible loess as set forth in claim 5, wherein: the distance between the adjacent test piles (4) is 1.5-2 meters.
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| CN202322716308.3U CN220978134U (en) | 2023-10-10 | 2023-10-10 | Negative frictional resistance detection test device for pile foundation in collapsible loess |
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| CN202322716308.3U CN220978134U (en) | 2023-10-10 | 2023-10-10 | Negative frictional resistance detection test device for pile foundation in collapsible loess |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117266270A (en) * | 2023-10-10 | 2023-12-22 | 中建新疆建工（集团）有限公司 | A test device and method for detecting negative friction resistance of pile foundations in collapsible loess |
| CN120822435A (en) * | 2025-09-18 | 2025-10-21 | 中煤江南建设发展集团有限公司 | A pile foundation settlement detection method and system for gradual sedimentation |
-
2023
- 2023-10-10 CN CN202322716308.3U patent/CN220978134U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117266270A (en) * | 2023-10-10 | 2023-12-22 | 中建新疆建工（集团）有限公司 | A test device and method for detecting negative friction resistance of pile foundations in collapsible loess |
| CN120822435A (en) * | 2025-09-18 | 2025-10-21 | 中煤江南建设发展集团有限公司 | A pile foundation settlement detection method and system for gradual sedimentation |
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