CN201649138U - Negative friction resistance testing device of cast-in-place concrete pile in self weight collapse loess - Google Patents
Negative friction resistance testing device of cast-in-place concrete pile in self weight collapse loess Download PDFInfo
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- CN201649138U CN201649138U CN2010201886534U CN201020188653U CN201649138U CN 201649138 U CN201649138 U CN 201649138U CN 2010201886534 U CN2010201886534 U CN 2010201886534U CN 201020188653 U CN201020188653 U CN 201020188653U CN 201649138 U CN201649138 U CN 201649138U
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Abstract
The utility model discloses a negative friction resistance testing device of a cast-in-place concrete pile in self weight collapse loess, comprising a water-immerged test pit positioned on foundation soil, wherein a test pile buried in the foundation soil is arranged in the water-immerged test pit and is provided with a test pile reserving section extending out of the water-immerged test pit, a water tank is arranged around the test pile reserving section, a water pipe for pumping underground water is arranged in the water tank, the upper part of the test pile reserving section is provided with a pile head, a first test pipe and a second test pipe are symmetrically and longitudinally arranged in a pile body of the test pile, a strain test probe capable of sliding along the first test pipe is arranged between a first test ring on the first test pipe and a third test ring, and a strain test probe capable of sliding along the second test pipe is arranged between a second test ring on the second test pipe and the third test ring. Strain test is carried out to the test pile reserving section so that the relation that creep degree changes along with time is obtained, and the creep degree of the test pile reserving section is used for representing the condition of the pile body in the soil, thereby the reliability of the negative friction resistance test of the cast-in-place concrete pile in self weight collapse loess is improved.
Description
Technical field
The utility model relates to a kind of self weight collapse loess place castinplace pile negative friction testing arrangement.
Background technology
Collapsible loess is a kind of special soil, extensively be distributed in northern China, it can sink under the effect of power and water, and wherein self weight collapse loess will be sunk by the water logging bubble under the effect of last earthing gravity pressure, thereby causes the stake in the self weight collapse loess to produce the negative friction effect.Carrying out important building, when structure are built, often needing negative friction is surveyed.In the current method of testing, main method is a pile body stress test method, promptly by the strain of test pile body, by elastic theory reference axis power, thereby obtains negative friction size and two parameters of Depth of Neutral.Its specific practice is, excavating an immersion around test pile tests pits, during test earlier in test pile pile crown hierarchical loading to a certain load, then under this constant load action, immersion tested pits soak, self weight collapse loess is issued in the effect of last earthing gravity pressure and water give birth to heavyly, be embedded in strain testing element in the test pile by test and obtain pile body strain variation in the soil body infall process, calculate the size and the Depth of Neutral of negative friction.Because the infall process of the soil body needs the time of tens days even up to a hundred days, make the pile body concrete be under the action of long-term load, therefore elastic strain except that taking place in concrete, also can creep, calculate pile body axle power if will survey strain by elastic theory, will produce than mistake, need deduction concrete creeping under action of long-term load just can make test result be tending towards actual.At present, how from the actual measurement strain deduction creep and also be not well solved.
The utility model content
The purpose of this utility model is to overcome above-mentioned deficiency of the prior art, and a kind of self weight collapse loess place castinplace pile negative friction testing arrangement is provided.By being reserved section, test pile carries out strain testing, thereby obtaining creep degree concerns over time, represent the situation of pile body in the soil with the creep degree of test pile reservation section, can calculate in the pile body creeping that degree of depth place concrete arbitrarily takes place under action of long-term load by the linearity theory of computation of creeping after having creep degree and concerning over time, improve the reliability of self weight collapse loess place castinplace pile negative friction test.
For achieving the above object, the technical solution adopted in the utility model is: self weight collapse loess place castinplace pile negative friction testing arrangement, comprise that the immersion that is positioned on the foundation soil tests pits, during testing pits, described immersion is provided with the test pile that is embedded in the foundation soil, described test pile has the test pile that stretching out soaks tests pits and reserves section, described test pile is provided with a tank around reserving section, be provided with the water pipe of groundwater abstraction in the described tank, it is pile crown that described test pile is reserved section top, be vertically arranged with first of symmetry in the test pile pile body and survey the pipe and the second survey pipe, the described first survey pipe and second is surveyed pipe and is formed by connecting by several survey pipe units, be provided with the survey ring in described adjacent two junctions of surveying pipe unit, first surveys pipe is provided with the first survey ring that is positioned at test pile reservation section top and is positioned at the 3rd survey ring that test pile is reserved section bottom, second surveys pipe is provided with the second survey ring that is positioned at test pile reservation section top and is positioned at the 4th survey ring that test pile is reserved section bottom, surveying interannular at the described first survey ring and the 3rd is provided with and can surveys the strain testing probe of pipe slip along first, surveying interannular at the described second survey ring and the 4th is provided with and can pops one's head in along the second survey pipe slip strain testing, the survey interannular strain that records by the strain testing probe is the strain that test pile is reserved section concrete, and two strain means of surveying pipe are mean strain.
Above-mentioned self weight collapse loess place castinplace pile negative friction testing arrangement, the length that described test pile is reserved section is 1m.
The utility model compared with prior art has the following advantages: the utility model carries out strain testing by test pile is reserved section, thereby obtaining creep degree concerns over time, represent the situation of pile body in the soil with the creep degree of test pile reservation section, can calculate in the pile body creeping that degree of depth place concrete arbitrarily takes place under action of long-term load by the linearity theory of computation of creeping after having creep degree and concerning over time, to creep and from the actual measurement strain, be deducted, accurately calculate pile body axle power by elastic theory again, improved the reliability of self weight collapse loess place castinplace pile negative friction test, and it is easy to use, easy to utilize.
Below by drawings and Examples, the technical solution of the utility model is described in further detail.
Description of drawings
Fig. 1 is a structural representation of the present utility model.
Fig. 2 reserves the local enlarged diagram of section for the utility model test pile.
Description of reference numerals:
The 1-immersion is tested pits; The 2-test pile is reserved section; The 3-tank;
The 4-motor-pumped well; 5-first surveys ring; 6-well water;
The 7-pile crown; 8-first surveys pipe; Pile body in the 9-soil;
The 10-water pipe; The 11-foundation soil; The 12-test pile;
13-second surveys ring; 14-the 4th surveys ring; 15-the 3rd surveys ring;
16-second surveys pipe.
The specific embodiment
A kind of self weight collapse loess place castinplace pile negative friction testing arrangement as shown in Figure 1, comprise that the immersion that is positioned on the foundation soil 11 tests pits 1, described immersion is tested pits and is provided with the test pile 12 that is embedded in the foundation soil 11 in 1, described test pile 12 has and stretching out test pits 1 test pile of immersion and reserve section 2, the length that described test pile is reserved section 2 can be 1m, described test pile is provided with a tank 3 around reserving section 2, be provided with the water pipe 10 of groundwater abstraction in the described tank 3, it is pile crown 7 that described test pile is reserved section 2 tops, be vertically arranged with first of symmetry in test pile 12 pile bodies and survey the pipe 8 and second survey pipe 16, described first surveys the pipe 8 and second survey pipe 16 survey pipe units by several length 1m is formed by connecting, be provided with the survey ring in described adjacent two junctions of surveying pipe unit, as shown in Figure 2, first surveys the 3rd survey ring 15 that pipe 8 is provided with the first survey ring 5 that is positioned at test pile reservation section 2 tops and is positioned at test pile reservation section 2 bottoms, second surveys the 4th survey ring 14 that pipe 16 is provided with the second survey ring 13 that is positioned at test pile reservation section 2 tops and is positioned at test pile reservation section 2 bottoms, surveying ring the 5 and the 3rd 15 on survey ring described first is provided with and can pops one's head in along the strain testing that the first survey pipe 8 slides, surveying ring the 13 and the 4th 14 on survey ring described second is provided with and can surveys pipe 16 slip strain testings probe along second, the survey interannular strain that records by the strain testing probe is the strain that test pile is reserved section concrete, and two strain means of surveying pipe are mean strain.
The operating principle of the utility model self weight collapse loess place castinplace pile negative friction testing arrangement is: when carrying out the negative friction test,, allow well water 6 overflow and enter the 1 interior maceration bubble self weight collapse loess that freely descends of testing pits that soaks in the well water 6 continual suction tanks 3 in the motor-pumped well 4 by water pipe 10 from tank 3 tops.Simultaneously in carrying out the negative friction test process, pile crown 7 tops are loaded with known dead load effect, can calculate test pile and reserve the compressive stress of section 2 ends, add the mean strain that takes place under the dead load effect that in test pile is reserved section 2, records, can obtain creep degree and concern over time.
Because when carrying out the pile foundation negative friction force test of self weight collapse loess place, foundation soil 11 all is among the immersion of water, just pile body 9 is in the middle of the immersion of water in the soil, so pile body 9 concrete water content are roughly the same in test pile reservation section 2 and the soil; Because the temperature at the following foundation soil 11 of underground certain depth is not subjected to the temperature variable effect, substantially constant, therefore the temperature of pile body 9 and well water 6 is suitable in the soil, with well water 6 uninterrupted injections in the tank 3, to make that the temperature of test pile reservation section 2 is suitable with well water 6, thereby pile body 9 concrete temperature are also suitable in test pile reservation section 2 and the soil.Simultaneously, by the strength grade of concrete (compressive strength is not less than 2.5Nmax/A) of control test pile 12, creeping of can making that the pile body concrete takes place crept for linearity.Because it is roughly the same that test pile is reserved pile body 9 concrete intensity in section 2 and the soil, temperature, water content, test pile reserve the creep degree that records in the section 2 in time variation relation applicable to the calculating of creeping of pile body in the soil 9, to survey and promptly obtain elastic strain after the strain deduction is crept, can calculate test pile axle power according to elastic theory, thereby obtain negative friction size and Depth of Neutral value more accurately.
The above; it only is preferred embodiment of the present utility model; be not that the utility model is imposed any restrictions; every according to the utility model technical spirit to any simple modification, change and equivalent structure transformation that above embodiment did, all still belong in the protection domain of technical solutions of the utility model.
Claims (2)
1. self weight collapse loess place castinplace pile negative friction testing arrangement, comprise the immersion that is positioned on the foundation soil (11) test pits (1), described immersion is tested pits and is provided with the test pile (12) that is embedded in the foundation soil (11) in (1), it is characterized in that: described test pile (12) has and stretching out the test pits test pile of (1) of immersion and reserve section (2), described test pile is reserved section (2) and is provided with a tank (3) on every side, be provided with the water pipe (10) of groundwater abstraction in the described tank (3), it is pile crown (7) that described test pile is reserved section (2) top, be vertically arranged with first of symmetry in test pile (12) pile body and survey the pipe (8) and the second survey pipe (16), the described first survey pipe (8) and second is surveyed pipe (16) and is formed by connecting by several survey pipe units, be provided with the survey ring in described adjacent two junctions of surveying pipe unit, first surveys pipe (8) is provided with the first survey ring (5) that is positioned at test pile reservation section (2) top and is positioned at the 3rd survey ring (15) that test pile is reserved section (2) bottom, second surveys pipe (16) is provided with the second survey ring (13) that is positioned at test pile reservation section (2) top and is positioned at the 4th survey ring (14) that test pile is reserved section (2) bottom, survey ring (5) and the 3rd described first and survey and be provided with between ring (15) and can survey the strain testing probe that pipe (8) slides along first, survey ring (13) and the 4th described second and survey to be provided with between ring (14) to survey and manage (16) slip strain testing and pop one's head in along second.
2. self weight collapse loess according to claim 1 place castinplace pile negative friction testing arrangement is characterized in that: the length that described test pile is reserved section (2) is 1m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201886534U CN201649138U (en) | 2010-05-13 | 2010-05-13 | Negative friction resistance testing device of cast-in-place concrete pile in self weight collapse loess |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201886534U CN201649138U (en) | 2010-05-13 | 2010-05-13 | Negative friction resistance testing device of cast-in-place concrete pile in self weight collapse loess |
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| Publication Number | Publication Date |
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| CN201649138U true CN201649138U (en) | 2010-11-24 |
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| CN2010201886534U Expired - Fee Related CN201649138U (en) | 2010-05-13 | 2010-05-13 | Negative friction resistance testing device of cast-in-place concrete pile in self weight collapse loess |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104099953A (en) * | 2013-04-08 | 2014-10-15 | 同济大学 | Centrifugal model testing device for simulating pressure water head change and stability of foundation pit |
| CN105649120A (en) * | 2016-03-11 | 2016-06-08 | 上海申元岩土工程有限公司 | Method for testing neutral point of negative friction of cast-in-place pile in deep backfilled soil |
| CN106013274A (en) * | 2016-07-06 | 2016-10-12 | 东南大学 | Pile foundation horizontal load comprehensive simulation test device for deep foundation pit excavation unloading field |
| CN106400768A (en) * | 2016-09-12 | 2017-02-15 | 中铁第勘察设计院集团有限公司 | Submerging test method for collapsible loess tunnel |
-
2010
- 2010-05-13 CN CN2010201886534U patent/CN201649138U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104099953A (en) * | 2013-04-08 | 2014-10-15 | 同济大学 | Centrifugal model testing device for simulating pressure water head change and stability of foundation pit |
| CN105649120A (en) * | 2016-03-11 | 2016-06-08 | 上海申元岩土工程有限公司 | Method for testing neutral point of negative friction of cast-in-place pile in deep backfilled soil |
| CN106013274A (en) * | 2016-07-06 | 2016-10-12 | 东南大学 | Pile foundation horizontal load comprehensive simulation test device for deep foundation pit excavation unloading field |
| CN106400768A (en) * | 2016-09-12 | 2017-02-15 | 中铁第勘察设计院集团有限公司 | Submerging test method for collapsible loess tunnel |
| CN106400768B (en) * | 2016-09-12 | 2019-01-11 | 中铁第一勘察设计院集团有限公司 | Collapsible loess tunnel submerging test method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101124 Termination date: 20130513 |