CN204101552U - Clay differential contraction stress measuring instrument - Google Patents

Clay differential contraction stress measuring instrument Download PDF

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Publication number
CN204101552U
CN204101552U CN201420557907.3U CN201420557907U CN204101552U CN 204101552 U CN204101552 U CN 204101552U CN 201420557907 U CN201420557907 U CN 201420557907U CN 204101552 U CN204101552 U CN 204101552U
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China
Prior art keywords
sample
clay
capsule
contraction stress
differential contraction
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Expired - Fee Related
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CN201420557907.3U
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Chinese (zh)
Inventor
谈云志
喻波
李典庆
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China Three Gorges University CTGU
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China Three Gorges University CTGU
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Abstract

A kind of clay differential contraction stress measuring instrument, be provided with the capsule be placed in sample in sample box, capsule is connected with pore water pressure sensor by water service pipe; Sample box is placed on meausring apparatus; Meausring apparatus is connected with data collector by signal wire with pore water pressure sensor.Experimental technique is, makes sample; Connect measuring instrument, obtain the change of moisture content in sample contraction process by meausring apparatus, the differential contraction stress being obtained sample by pore water pressure sensor changes; When pore water pressure keeps invariable, terminate experiment; Clay differential contraction stress experiments of measuring is realized by above-mentioned steps.The utility model provides by arranging capsule in sample, coordinate high precision pore water pressure sensor, the differential contraction stress data of clay sample can be obtained, coordinate accurate meausring apparatus, the utility model can also obtain change of moisture content in clay contraction process and differential contraction stress change between relation.

Description

Clay differential contraction stress measuring instrument
Technical field
The present invention relates to Geotechnical Engineering field, especially a kind of clay differential contraction stress measuring instrument.
Background technology
Swell-shrink characteristic clay (as swelled ground, red clay) has the bad water Li Tezheng such as water-swellable, dehydration shrinkage, and the breathing feature grasping such special clay carries out the element task of engineering design, construction.At present, the index describing cohesive soil expansion behavior has free swelling rate, there is (no) lotus expansivity and bulging force; But the index describing cohesive soil shrinkage characteristic then only has line shrinkage and body shrinkage, and ungauged regions power.And clay water loss shrinkage cracking is one of key factor of bringing out the catastrophe of swell-shrink characteristic clay engineering.Obviously, be difficult to realize by the cracking behaviors of the drawdown deformation prediction soil body, differential contraction stress is then the parameter carrying out judging that whether clay ftractures.But the measuring method of bulging force and convergent force has significant difference, the former outside expansion deformation, therefore directly can be measured by expansion back-pressure or force snesor; The latter belongs to toe-in, does not also have ready-made method and instrument to apply so far.
Summary of the invention
Technical matters to be solved by this invention is to provide a kind of clay differential contraction stress measuring instrument, can determine cohesive soil differential contraction stress, and the change of moisture content that can obtain in clay contraction process and differential contraction stress change between corresponding relation and the estimated value of contraction.
For solving the problems of the technologies described above, the technical solution adopted in the present invention is: a kind of clay differential contraction stress measuring instrument,
At least one end face of sample box is open, and be provided with the capsule be placed in sample in sample box, capsule is connected with pore water pressure sensor by water service pipe;
Sample box is placed on meausring apparatus;
Meausring apparatus is connected with data collector by signal wire with pore water pressure sensor.
Heated base is provided with in the bottom of sample box.
Adherent layer is provided with at sample box inwall.
Described capsule becomes column, through sample, and the two ends of capsule are respectively equipped with water inlet end screw plug and water side screw plug, and water side screw plug is provided with the second valve, and water inlet end screw plug is connected with water service pipe.
Water service pipe is provided with VERTICAL TUBE, and VERTICAL TUBE is provided with the first valve, and water service pipe is provided with the 3rd valve between VERTICAL TUBE joint and pore water pressure sensor.
Described water service pipe is supported on bracing frame.
A kind ofly above-mentioned clay differential contraction stress measuring instrument is adopted to carry out the method for testing:
One, sample is made;
Two, fill liquid in the capsule in sample, and be communicated with pore water pressure sensor by water service pipe;
Three, sample box entirety is placed on meausring apparatus, pore water pressure sensor is connected with data collector with meausring apparatus;
Four, obtain the change of moisture content in sample contraction process by meausring apparatus, the differential contraction stress being obtained sample by pore water pressure sensor changes;
When pore water pressure keeps invariable, terminate experiment;
Clay differential contraction stress experiments of measuring is realized by above-mentioned steps.
When making compacting sample, in sample box, apply adherent layer, below capsule position, first place mat one deck soil sample, installs capsule after pressing, inserts multiple ring lobe plate in capsule, and multiple ring lobe plate is coated on outside support column;
Support column reaches in sample box areole, and is formed with the hole of sample box sidewall and be sealed and matched, and covers remaining soil sample, with sampling machine compacting above capsule;
Extract support column and ring lobe plate out, be installed into water end (W.E.) screw plug and water side screw plug, filling liquid in capsule, obtained the sample of compacting by above-mentioned steps.
When making native cream sample, to capsule-filling liquid, two ends water inlet end screw plug and water side screw plug shutoff, in sample box, apply adherent layer, after clay furnishing soil cream, in sample box, pour a part of native cream into, capsule is installed, water inlet end screw plug and water side screw plug stretch out the sidewall of sample box, bring the native cream of residue into, with doctor blade.
Bottom sample box, arrange heated base, heating-up temperature is up to 30 ~ 35 DEG C;
Water service pipe arranges VERTICAL TUBE, and the first valve is set in VERTICAL TUBE, by VERTICAL TUBE, water is injected in capsule during experiment, and in experimentation, close the first valve.
A kind of clay differential contraction stress measuring instrument provided by the invention, by arranging capsule in sample, coordinate high precision pore water pressure sensor, the differential contraction stress data of clay sample can be obtained, coordinate accurate meausring apparatus, device of the present invention can also obtain change of moisture content in clay contraction process and differential contraction stress change between relation.Clay differential contraction stress measuring instrument low cost of manufacture of the present invention, is beneficial to making, and operation steps is easy to realize, and measuring accuracy is high, both can measure the differential contraction stress of viscosity soil sample, also can estimate that the liquid shrinkable of sample becomes.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described:
Fig. 1 is the one-piece construction schematic diagram of measuring instrument in the present invention.
Fig. 2 is the structural representation of sampling machine.
Fig. 3 is the structural representation of capsule in the present invention.
Fig. 4 is the cross sectional representation of capsule and ring lobe plate in the present invention, support column.
In figure: sample box 1, adherent layer 101, heated base 2, sample 3, capsule 4, water inlet end screw plug 41, water side screw plug 42, ring lobe plate 43, support column 44, meausring apparatus 5, water service pipe 6, the first valve 7, second valve the 8, three valve 9, VERTICAL TUBE 10, pore water pressure sensor 11, data collector 12, pressure head 13, bracing frame 14, reaction frame 15, hydraulic cylinder 16.
Embodiment
Embodiment 1:
As in Fig. 1, a kind of clay differential contraction stress measuring instrument, at least one end face of sample box 1 is open, sample box 1 upper surface exploitation in this example, moisture in order to sample 3 in sample box 1 evaporates, be provided with the capsule 4 be placed in sample 3 in sample box 1, be filled with liquid in capsule 4, capsule 4 is connected with pore water pressure sensor 11 by water service pipe 6; Pore water pressure sensor 11 minimum resolution in this example can reach 1kPa.
Sample box 1 is placed on meausring apparatus 5; Meausring apparatus 5 in this example adopts electronic balance, and weighing precision is 0.001g, and range is about 5kg.The data of evaporation capacity are sent in real time by meausring apparatus 5.
Meausring apparatus 5 and pore water pressure sensor 11 are electrically connected with data collector 12 by signal wire.
In preferred scheme, be provided with heated base 2 in the bottom of sample box 1.Structure thus, accelerates the velocity of evaporation of sample 3.Adopt low power heating film in this example, heating-up temperature is up to 30 ~ 35 DEG C.
In preferred scheme, be provided with adherent layer 101 at sample box 1 inwall.Structure thus, can not affect the contraction of sample 3.Adherent layer 101 can adopt vaseline, or other materials, such as, lubricate butter.
Preferred scheme is as in Fig. 3, described capsule 4 one-tenth column, through sample 3, the two ends of capsule 4 are respectively equipped with water inlet end screw plug 41 and water side screw plug 42, the sidewall of water inlet end screw plug 41 and the through sample box 1 of water side screw plug 42, water side screw plug 42 is provided with the second valve 8, and water inlet end screw plug 41 is connected with water service pipe 6.Structure thus, is convenient to the installation of capsule 4, is also convenient to filling liquid in capsule 4.
Preferred scheme is as in Fig. 1, and water service pipe 6 is provided with VERTICAL TUBE 10, and VERTICAL TUBE 10 is provided with the first valve 7, and water service pipe 6 is provided with the 3rd valve 9 between VERTICAL TUBE 10 joint and pore water pressure sensor 11.The VERTICAL TUBE 10 arranged is convenient to add water in water service pipe 6 when testing, thus is convenient to water to join in capsule 4.
Preferred scheme is as in Fig. 1, and described water service pipe 6 is supported on bracing frame 14.The bracing frame 14 arranged keeps balance for making water service pipe 6, thus the weight change of sample box 1 can not be affected, namely when sample 3 evaporates, water service pipe 6 is not locked, thus can slide along bracing frame 14, be convenient to whole water service pipe 6 like this and all adopt hard material, in order to avoid soft water service pipe 6 self-expanding affects measuring accuracy.
Embodiment 2:
A kind ofly above-mentioned clay differential contraction stress measuring instrument is adopted to carry out the method for testing:
The principle of work of apparatus of the present invention fills liquid by capsule 4 and water service pipe 6, such as distilled water, clay sample generation dehydration shrinkage under spontaneous evaporation or low heated at constant temperature effect, contraction process causes the change of soil sample inner structure, produce differential contraction stress simultaneously, by the topping up body capsule of extruded sample inside, thus differential contraction stress is conducted in pore water pressure sensor 11, thus obtain the differential contraction stress that sample produces in contraction process.Meanwhile, utilize accurate meausring apparatus 5 can measure the change of water cut in sample contraction process, thus obtain the rule of differential contraction stress and change of moisture content in the whole contraction process of sample.
Experiment concrete steps are as follows:
One, sample 3 is made;
Soil sample water cut w is configured according to test plan, optionally, when making compacting sample, in sample box 1, apply adherent layer 101, first place mat one deck soil sample below capsule 4 position, after flattening, capsule 4 is installed, insert multiple ring lobe plate 43 in capsule 4, in this example, be 3, between ring lobe plate 43, be provided with chamfering along vertical edge edge, to form the breach that is positioned at inwall, be convenient to the taking-up of ring lobe plate 43.Multiple ring lobe plate 43 is coated on outside support column 44, as shown in Figure 4, before inserting, smears vaseline at ring lobe plate 43 and support column 44 outside surface, so that sample makes rear taking-up ring lobe plate 43 and support column 44;
Support column 44 reaches in sample box 1 areole, and is formed with the hole of sample box 1 sidewall and be sealed and matched, and covers remaining soil sample, with sampling machine compacting, as shown in Figure 2 above capsule 4; Sample box 1 is placed in reaction frame 15, and pressure head 13 is placed in sample box 1, is provided with the hydraulic cylinder 16 for upper top below sample box 1.During compacting, first artificial precompressed pressure head 13 makes sample 3 be compacted to a certain degree, then sample box 3 entirety is put into reaction frame 15, primer fluid cylinder pressure 16, and when after pressure head 13 lower end lateral margin and sample box 3 edge contact, sample compacting completes.After stopping pressurization, maintain 2 ~ 3 minutes, prevent sample resilience.After sample preparation completes, extract support column 44 and ring lobe plate 43 out, be installed into water end (W.E.) screw plug 41 and water side screw plug 42, filling liquid in capsule 4, obtained the sample of compacting by above-mentioned steps.
When making native cream sample, to capsule 4 filling liquid, two ends water inlet end screw plug 41 and water side screw plug 42 shutoff, in sample box 1, apply adherent layer 101, after clay furnishing soil cream, in sample box 1, pour a part of native cream into, capsule 4 is installed, water inlet end screw plug 41 and water side screw plug 42 stretch out the sidewall of sample box 1, bring the native cream of residue into, with doctor blade.
Two, fill liquid in the capsule 4 in sample 3, and be communicated with pore water pressure sensor 11 by water service pipe 6;
Preferably, water service pipe 6 arranges VERTICAL TUBE 10, and the first valve 7 is set in VERTICAL TUBE 10, by VERTICAL TUBE 10, water is injected in capsule 4 during experiment, and in experimentation, close the first valve 7.
Three, sample box 1 entirety is placed on meausring apparatus 5, pore water pressure sensor 11 is connected with data collector 12 with meausring apparatus 5; And data are reset, start to record data.
Preferably, arrange heated base 2 bottom sample box 1, and be placed on meausring apparatus 5 together, heating-up temperature is up to 30 ~ 35 DEG C.
Four, obtain the change of moisture content in sample 3 contraction process by meausring apparatus 5, the differential contraction stress being obtained sample 3 by pore water pressure sensor 11 changes;
For compacting sample, after sample preparation, sample box 1 is placed on heated base 2, and is placed on meausring apparatus 5 together; Water inlet end screw plug 41 is communicated with water service pipe 6, water service pipe 6 is provided with VERTICAL TUBE 10, the second valve 8 is provided with at water side screw plug 42, VERTICAL TUBE 10 is provided with the first valve 7, water service pipe 6 is provided with the 3rd valve 9, preferred VERTICAL TUBE 10 keeps balance by bracing frame 14, and more preferably pore water pressure sensor 11 and water service pipe 6 are all placed on meausring apparatus 5, to guarantee the weight change that accurate weighing sample 3 evaporates.
Open the first valve 7, close the second valve 8 and the 3rd valve 9, distilled water is enable to enter in columniform capsule 4, and filled, connect pore water pressure sensor 11 again, and open the 3rd valve 9, make the fractional flooding not having water-filling in water service pipe 6, can adjustment first valve 7, second valve 8 be passed through, guarantee in water service pipe 6 and capsule 4 not bubbles; After above-mentioned steps completes, close the first valve 7, second valve 8, open the 3rd valve 9.Open heated base 2, meausring apparatus 5 and data collector 12, and data are reset, start to record data; When pore water pressure is invariable, test can be terminated; After terminating test, store data; The data of Collect jointly and basic data, obtain the differential contraction stress of respective samples and the estimated value of contraction.
For native cream sample owing to being connected with water service pipe 6 by columniform capsule 4 when sample preparation, therefore only need Bonding pressure sensor 7, all the other operation stepss are consistent with the operation steps of compacting sample.
Clay differential contraction stress experiments of measuring is realized by above-mentioned steps.
The above embodiments are only the preferred technical solution of the present invention; and should not be considered as restriction of the present invention; the technical scheme that protection scope of the present invention should be recorded with claim, the equivalents comprising technical characteristic in the technical scheme of claim record is protection domain.Namely the equivalent replacement within the scope of this improves, also within protection scope of the present invention.

Claims (6)

1. a clay differential contraction stress measuring instrument, is characterized in that:
At least one end face of sample box (1) is open, and be provided with the capsule (4) be placed in sample (3) in sample box (1), capsule (4) is connected with pore water pressure sensor (11) by water service pipe (6);
Sample box (1) is placed on meausring apparatus (5);
Meausring apparatus (5) is connected with data collector (12) by signal wire with pore water pressure sensor (11).
2. a kind of clay differential contraction stress measuring instrument according to claim 1, is characterized in that: be provided with heated base (2) in the bottom of sample box (1).
3. a kind of clay differential contraction stress measuring instrument according to claim 1, is characterized in that: be provided with adherent layer (101) at sample box (1) inwall.
4. a kind of clay differential contraction stress measuring instrument according to claim 1, it is characterized in that: described capsule (4) becomes column, through sample (3), the two ends of capsule (4) are respectively equipped with water inlet end screw plug (41) and water side screw plug (42), water side screw plug (42) is provided with the second valve (8), and water inlet end screw plug (41) is connected with water service pipe (6).
5. a kind of clay differential contraction stress measuring instrument according to claim 1, it is characterized in that: water service pipe (6) is provided with VERTICAL TUBE (10), VERTICAL TUBE (10) is provided with the first valve (7), and water service pipe (6) is provided with the 3rd valve (9) between VERTICAL TUBE (10) joint and pore water pressure sensor (11).
6. a kind of clay differential contraction stress measuring instrument according to claim 5, is characterized in that: described water service pipe (6) is supported on bracing frame (14).
CN201420557907.3U 2014-09-26 2014-09-26 Clay differential contraction stress measuring instrument Expired - Fee Related CN204101552U (en)

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Application Number Priority Date Filing Date Title
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104316670A (en) * 2014-09-26 2015-01-28 三峡大学 Clay shrinkage stress measuring instrument and experimental method
CN106441671A (en) * 2016-09-14 2017-02-22 青海省交通科学研究院 Liquid-filled soil stress test device and test method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104316670A (en) * 2014-09-26 2015-01-28 三峡大学 Clay shrinkage stress measuring instrument and experimental method
CN104316670B (en) * 2014-09-26 2016-08-24 三峡大学 Clay shrinkage stress measuring instrument and experimental technique
CN106441671A (en) * 2016-09-14 2017-02-22 青海省交通科学研究院 Liquid-filled soil stress test device and test method

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CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20150114

Termination date: 20150926

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