CN104831763A - Frost heaving prevention performance test experiment device and method for pile body - Google Patents
Frost heaving prevention performance test experiment device and method for pile body Download PDFInfo
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- CN104831763A CN104831763A CN201510296757.4A CN201510296757A CN104831763A CN 104831763 A CN104831763 A CN 104831763A CN 201510296757 A CN201510296757 A CN 201510296757A CN 104831763 A CN104831763 A CN 104831763A
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Abstract
The invention discloses a frost heaving prevention performance test experiment device and method for a pile body. The frost heaving prevention performance test experiment device comprises a sample cylinder, a cold bathing plate, a fixed support and a base. In order not to limit the frost heaving prevention of the pile body, a central circular hole is formed in the cold bathing plate. The fixed support is formed by assembling a stainless steel annular plate, stainless steel connection rods and a stainless steel circular plate. An annular refrigerating fluid circulation pipe is arranged on the base and provides temperature for the bottom of a sample. Small circular holes are densely distributed in a water-permeable plate on the base. The method includes the steps of placing the sample cylinder in the fixed support, installing the base, filling the sample cylinder with the test pile body and soil materials according to test requirements, placing the cold bathing plate to the top of the sample, connecting the cold bathing plate, a refrigerating fluid outlet of the base and a refrigerating fluid inlet of the base to an external refrigeration device, starting the refrigeration device and a collection device, and starting the test. The frost heaving performance such as frost heaving displacement and frost heaving force of pile foundations in frozen earth areas can be tested indoors, test factors can be controlled, operation is convenient, workloads of site tests are greatly reduced, and the frozen earth testing technical means are further enriched.
Description
Technical field
The present invention relates to a kind of pile body anti_freeze uplift performance test experimental apparatus and experimental technique thereof, belong to indoor geotechnological low-temperature test technical field.
Background technology
The area of ever-frozen ground accounts for 22.3% of China's gross area, and seasonal frozen ground and short-term frozen soil are then throughout more than half China.Be easy to produce lifting by frost phenomenon in seasonal frozen soil region pile foundation, thus cause superstructure to produce uneven change and affect normal use and even destroy.Therefore, in order to develop permafrost region, ensure the stable of permafrost region superstructure, the interaction between research frozen soil and pile foundation, the lifting by frost phenomenon reducing pile foundation has important meaning.
For a long time, the lifting by frost research of pile foundation has two kinds of modes: one is carry out field trial; Two is adopt finite element software to carry out simulation calculation.Field trial expends huge manpower, financial resources, and elapsed cycles is long, and uncontrollable factor is many, poor repeatability, is unfavorable for studying respectively each factor.Finite element software simulation calculation is comparatively large by the impact of fringe conditions, stress and strain model, and different software result of calculation is different, the correctness of result is under suspicion, can not instructs Practical Project.These all cause there is significant limitation to the research of pile foundation anti_freeze uplift.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of convenience simple to operate, efficient, is convenient to pile body anti_freeze uplift performance test experimental apparatus and the experimental technique thereof of control, it can simulate frozen ground regions pile foundation lifting by frost phenomenon completely, greatly reduce the workload of field trial, enrich frozen soil experiment technological means.
For solving the problems of the technologies described above, the technical scheme that this Sample devices is taked is: a kind of pile body anti_freeze uplift performance test experimental apparatus, and its key technology is: it comprises test specimen tube, be located at cryostat dish above the inner sample of test specimen tube, for the fixed support of fixing test specimen tube and the base that is positioned at below sample;
Described test specimen tube comprises organic glass infuser body, be positioned at machine glass infuser with it face organic glass ring flat-plate, be positioned at machine glass infuser with it below plexiglass base plate and the stainless steel larynx hoop playing reinforcement effect that is installed on organic glass stack shell outer wall, described organic glass stack shell bottom is provided with water supplement port and exhaust opening;
Described cryostat dish comprise stainless steel circle box, be positioned at stainless steel circle box in the middle of center hole, be arranged at stainless steel circle box above freezing liquid import and outlet;
Described base comprise be located at pile body bracket below sample successively, in order to simulated groundwater supply porous disc and annular freezing liquid circulation pipe, the freezing liquid import of described annular freezing liquid circulation pipe and freezing liquid outlet extend to test specimen tube outside;
Described fixed support comprises and being positioned at stainless steel ring flat-plate above organic glass ring flat-plate, being positioned at the stainless steel plectane below plexiglass base plate and the stainless steel connecting rod for connecting stainless steel ring flat-plate and stainless steel plectane.
Described stainless steel larynx hoop gathers outside organic glass stack shell, prevents organic glass stack shell from deforming.
Described center hole diameter is greater than sample top diameter.
Described annular freezing liquid circulation pipe is annular copper pipe.
Described porous disc is covered with permeable small sircle hole.
Described pile body bracket is organic glass plectane.
Described pile body bracket diameter slightly larger than pile body base diameter, in order to prevent the soil body from entering bottom pile body, with reach only test pile side to the object of body frost heaving affecting laws.
Experimental technique of the present invention is: be first placed in fixed support by test specimen tube, and bottom mounting seat to test specimen tube, then sample is placed on bracket, and fill soil compaction, again cryostat dish is placed on sample top, connect the freezing liquid import on freezing liquid import on cryostat dish and outlet and base respectively and be exported to external refrigerating plant, connect water supplement port to external geneva water bottle, and self cooling for displacement transducer bath center hole is placed on test pile body top, open refrigerating plant and harvester, start test.
Freezing process of the present invention is unidirectional cooling mode from top to bottom.Before freezing process starts, sample need carry out the process of 12h constant temperature, when temperature is consistent in the soil body, then starts to lower the temperature and opens water supplement port.
The beneficial effect adopting technique scheme to produce is:
1, the present invention is provided with test specimen tube, cryostat dish, fixed support and base, and be placed on by sample on base, overall structure is fairly simple, simple to operate, efficiently facilitates, and result of use is good, effectively simulates the lifting by frost phenomenon of pile foundation.
2, owing to adopting this device can carry out in laboratory, utilize external refrigerating plant precise control of temperature to change, substantially reduce the elapsed time of cyclic test, improve experiment work efficiency; Soil sample when simultaneously also ensure that each test has identical initial temperature, accurately can control the test temperature of each sample, effectively improve the comparative of experimental data.
3, because external refrigerating plant is connected to provide the freezing liquid with steady temperature with base and cryostat dish respectively, thus the object of the soil body being carried out to unidirectional cooling, simulated field soil body Unidirectional Freezing is reached.
4, by arranging water supplement port and exhaust opening, connecting geneva bottle and carrying out moisturizing, the groundwater recharge under simulation Unidirectional Freezing pattern, thus contrast with without groundwater recharge.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention;
Fig. 2 is the schematic diagram of cryostat dish;
Fig. 3 is the schematic diagram of porous disc;
Fig. 4 is the schematic diagram of annular freezing liquid circulation pipe;
Wherein, 1, test specimen tube, 1-1, organic glass stack shell, 1-2, organic glass ring flat-plate, 1-3, stainless steel larynx hoop, 1-4, plexiglass base plate, 1-5, water supplement port, 1-6, exhaust opening; 2, cryostat dish, 2-1, stainless steel circle box, 2-2, center hole, 2-3, freezing liquid import, 2-4, freezing liquid export; 3, fixed support, 3-1, stainless steel ring flat-plate, 3-2, stainless steel connecting rod, 3-3 stainless steel plectane; 4, base, 4-1, pile body bracket, 4-2, porous disc, 4-3, annular freezing liquid circulation pipe, 4-4, freezing liquid import, 4-5, freezing liquid export, and 5, sample; 6, the soil body.
Detailed description of the invention
Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.
See accompanying drawing 1-accompanying drawing 4, the present embodiment comprises test specimen tube 1, be located at cryostat dish 2 above the inner sample of test specimen tube 15, for the fixed support 3 of fixing test specimen tube 1 and the base 4 that is positioned at below sample 5;
Described test specimen tube 1 comprises organic glass infuser body 1-1, is positioned at the organic glass ring flat-plate 1-2 above organic glass stack shell 1-1, the plexiglass base plate 1-4 being positioned at machine glass stack shell 1-1 top and bottom and the stainless steel larynx hoop 1-3 playing reinforcement effect be installed on organic glass stack shell 1-1 outer wall, and described organic glass stack shell 1-1 bottom is provided with water supplement port 1-5 and exhaust opening 1-6; Described stainless steel larynx hoop 1-3 gathers outside organic glass stack shell 1-1, prevents organic glass stack shell from deforming.
Described cryostat dish 2 comprises stainless steel circle box 2-1, is positioned at the middle center hole 2-2 of stainless steel circle box 2-1, is arranged at the freezing liquid import 2-3 above stainless steel circle box 2-1 and exports 2-4; Described center hole 2-2 diameter is greater than sample 5 top diameter, prevents from having an impact to the displacement of pile body.
Described base 4 comprise be located at pile body bracket 4-1 below sample 5 successively, to extend to test specimen tube 1 in order to the porous disc 4-2 of simulated groundwater supply and annular freezing liquid circulation pipe 4-3, the freezing liquid import 4-4 of described annular freezing liquid circulation pipe 4-3 and freezing liquid outlet 4-5 outside; Described annular freezing liquid circulation pipe 4-3 is annular copper pipe.Wherein pile body bracket 4-1 is poly (methyl methacrylate) plate, diameter slightly larger than sample 5 base diameter, in order to prevent the soil body from entering bottom sample 5, to reach the object of only test sample 5 side direction body frost heaving affecting laws, porous disc 4-2 is covered with permeable small sircle hole, in order to simulated groundwater supply.
Described fixed support 3 comprises and being positioned at stainless steel ring flat-plate 3-1 above organic glass ring flat-plate 1-2, being positioned at the stainless steel plectane 3-3 below plexiglass base plate 1-4 and the stainless steel connecting rod 3-2 for connecting stainless steel ring flat-plate 3-1 and stainless steel plectane 3-3.The present invention can in lifting by frost performances such as indoor test permafrost region pile foundation lifting by frost displacement, lifting by frost power.
Below by embodiment, experimental technique of the present invention is described.
Embodiment 1
Under closed not supplying water condition, the lifting by frost displacement performance test implementation process of pile body is:
Base 4 to be mounted to bottom test specimen tube 1 and to be placed in fixed support 3, then namely sample 5(is tested pile body) be placed on pile body bracket 4-1, and fill soil compaction by test requirements document, period layered arrangement temperature pick up, again cryostat dish 2 is placed on sample 5 top, external refrigerating plant connected respectively the freezing liquid import 2-3 on cryostat dish 2 and export 2-4 to reach the effect of Control Assay 5 head temperature, external refrigerating plant is connected respectively freezing liquid import 4-4 on base 4 and freezing liquid outlet 4-5 to reach the effect of Control Assay 5 bottom temp, close water supplement port 1-5 and exhaust opening 1-6 simultaneously, and self cooling for displacement transducer bath center hole 2-2 is placed on sample 5 top, open refrigerating plant and harvester, start test.After end to be tested, take cryostat dish 2 away and carry out tearing sample open, finally complete test.Wherein, described refrigerating plant is for providing the cryogenic thermostat cryostat of the freezing liquid of steady temperature, and described harvester is DT80 data acquisition unit, can the data such as collecting temperature, displacement.Described refrigerating plant and harvester adopt existing product, and the refrigerating plant in embodiment 2 and harvester are with embodiment 1.
Embodiment 2
Opening wide the lifting by frost power performance test implementation process of pile body under supplying water condition is:
Base 4 to be mounted to bottom test specimen tube 1 and to be placed in fixed support 3, then sample 5 is placed on pile body bracket 4-1, and fill soil compaction by test requirements document, period layered arrangement temperature pick up, pressure sensor, again cryostat dish 2 is placed on sample 55 top, external refrigerating plant connected respectively the freezing liquid import 2-3 on cryostat dish 2 and export 2-4 to reach the effect of Control Assay 5 head temperature, external refrigerating plant is connected respectively freezing liquid import 4-4 on base 4 and freezing liquid outlet 4-5 to reach the effect of Control Assay bottom temp, water supplement port 1-5 is connected with geneva bottle, and self cooling for pressure sensor bath center hole is placed on test pile body top, open water supplement port 1-5 and exhaust opening 1-6, exhaust opening 1-6 is closed when liquid level and porous disc 4-2 flush, and self cooling for position pressure sensor bath center hole 2-2 is placed on test pile body top, place high-strength steel sheet at pressure sensor end face simultaneously, and weld together with fixed support 3, prevent that putting pile body is subjected to displacement.Open refrigerating plant and harvester, start test.After end to be tested, take cryostat dish 2 away and carry out tearing sample open, finally complete test.
Claims (10)
1. a pile body anti_freeze uplift performance test experimental apparatus, is characterized in that: it comprises test specimen tube (1), be located at the cryostat dish (2) of inner sample (5) top of test specimen tube (1), for fixing test specimen tube (1) fixed support (3) and be positioned at the base (4) of sample (5) below;
Described test specimen tube (1) comprises organic glass infuser body (1-1), be positioned at organic glass ring flat-plate (1-2) above organic glass stack shell (1-1), be positioned at the plexiglass base plate (1-4) below machine glass stack shell (1-1) and be installed on the stainless steel larynx hoop (1-3) playing reinforcement effect on organic glass stack shell (1-1) outer wall, and described organic glass stack shell (1-1) bottom is provided with water supplement port (1-5) and exhaust opening (1-6);
Described cryostat dish (2) comprises stainless steel circle box (2-1), is positioned at the middle center hole (2-2) of stainless steel circle box (2-1), is arranged at the freezing liquid import (2-3) above stainless steel circle box (2-1) and exports (2-4);
Described base (4) comprise be located at sample (5) below successively pile body bracket (4-1), in order to the porous disc (4-2) of simulated groundwater supply and annular freezing liquid circulation pipe (4-3), the freezing liquid import (4-4) of described annular freezing liquid circulation pipe (4-3) and freezing liquid outlet (4-5) extend to test specimen tube (1) outside;
Described fixed support (3) comprises the stainless steel ring flat-plate (3-1) being positioned at organic glass ring flat-plate (1-2) top, the stainless steel plectane (3-3) being positioned at plexiglass base plate (1-4) below and stainless steel connecting rod (3-2) for connecting stainless steel ring flat-plate (3-1) and stainless steel plectane (3-3).
2. a kind of pile body anti_freeze uplift performance test experimental apparatus according to claim 1, is characterized in that: described stainless steel larynx hoop (1-3) is gathered in organic glass stack shell (1-1) outside.
3. a kind of pile body anti_freeze uplift performance test experimental apparatus according to claim 1, is characterized in that: described center hole (2-2) diameter is greater than sample (5) top diameter.
4. a kind of pile body anti_freeze uplift performance test experimental apparatus according to claim 1, is characterized in that: described annular freezing liquid circulation pipe (4-3) is annular copper pipe.
5. a kind of pile body anti_freeze uplift performance test experimental apparatus according to claim 1, is characterized in that: described porous disc (4-2) is covered with permeable small sircle hole.
6. a kind of pile body anti_freeze uplift performance test experimental apparatus according to claim 1, is characterized in that: described pile body bracket (4-1) is organic glass plectane.
7. a kind of pile body anti_freeze uplift performance test experimental apparatus according to claim 6, is characterized in that: described pile body bracket (4-1) diameter is slightly larger than pile body base diameter.
8. the experimental technique of the pile body anti_freeze uplift performance test experimental apparatus described in any one of claim 1-7, it is characterized in that: first test specimen tube (1) is placed in fixed support (3), and mounting seat (4) is to test specimen tube (1) bottom, then sample (5) is placed on bracket (4-1), and fill earth material (6) compacting, again cryostat dish (2) is placed on sample (5) top, connect freezing liquid import (2-3) and the freezing liquid import (4-4) exported on (2-4) and base (4) in cryostat dish (2) respectively and export (4-5) to external refrigerating plant, connect water supplement port (1-5) to external geneva water bottle, and self cooling for displacement transducer bath center hole (2-2) is placed on test pile body top, open refrigerating plant and harvester, start test.
9. the experimental technique of pile body anti_freeze uplift performance test experimental apparatus according to claim 8, is characterized in that: the freezing process of the method is unidirectional cooling mode from top to bottom.
10. the experimental technique of pile body anti_freeze uplift performance test experimental apparatus according to claim 9, is characterized in that: before freezing process starts, and sample need carry out the process of 12h constant temperature, when temperature is consistent in the soil body, then starts to lower the temperature and opens water supplement port (1-5).
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| CN115876579A (en) * | 2022-08-25 | 2023-03-31 | 中国科学院西北生态环境资源研究院 | Creep test method for pile-frozen soil shear sample |
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