CN114315228A - Preparation method of polyurethane-cured calcareous sand triaxial sample - Google Patents
Preparation method of polyurethane-cured calcareous sand triaxial sample Download PDFInfo
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- CN114315228A CN114315228A CN202111361357.9A CN202111361357A CN114315228A CN 114315228 A CN114315228 A CN 114315228A CN 202111361357 A CN202111361357 A CN 202111361357A CN 114315228 A CN114315228 A CN 114315228A
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- calcareous sand
- polyurethane
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- calcareous
- triaxial
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Abstract
The invention discloses a preparation method of a triaxial sample of polyurethane cured calcareous sand, which can realize convenient preparation of the triaxial sample of the polyurethane cured calcareous sand and comprises the following steps: screening and elutriating calcareous sand particles; drying the treated calcareous sand particles; mixing and stirring the dried calcareous sand and the polyurethane white liquid; mixing and stirring a mixture of calcareous sand and polyurethane white liquor and polyurethane black liquor; and (5) carrying out layered compaction sample preparation and sample maintenance. The method is convenient and fast to operate, simple in process, capable of effectively improving the mechanical behavior of the calcareous sand, providing a new technology and a new idea for the treatment of the calcareous sand foundation in the island engineering, and high in practical engineering application value.
Description
Technical Field
The invention relates to a geotechnical engineering research method, in particular to a preparation method of a polyurethane solidified calcareous sand triaxial sample, and belongs to the field of civil engineering.
Background
With the continuous development of the reef island engineering, various reef island engineering structures are gradually built in the south China sea field, and the calcareous sand is widely applied as a main foundation material and a building material in the process of carrying out the reef island engineering construction in the south China sea field. Due to the special biological cause of the calcareous sand, the mechanical behavior and the physical characteristics of the calcareous sand are greatly different from those of the common land-source sand. In terms of basic physical and mechanical characteristics, the calcareous sand has the undesirable characteristics of low crushing strength, strong permeability, high compression and the like; for practical engineering, the calcareous sand as a foundation material has the characteristics of too small bearing capacity, too remarkable uneven settlement and the like. In the island engineering construction process, certain reinforcement treatment is necessary for calcareous sand foundations to avoid the occurrence of engineering safety problems.
At present, many scholars try to perform curing treatment on calcareous sand by different modes, such as cement curing treatment, biological curing treatment and the like. Although different curing modes can improve the mechanical behavior characteristics of the calcareous sand part, the whole effect is not ideal, and the main reasons are that the curing process is complex and the practical engineering application value is low. As a novel polymer curing material, the polyurethane can effectively enhance the bonding among particles, so that the overall strength performance of the granular material is obviously enhanced, the reaction time is short, and the operation mode is convenient. In addition, the polyurethane has better water resistance and lower pollution, so the environmental pollution can be reduced by adopting the polyurethane for curing improvement. Therefore, the invention provides the sample preparation method which is convenient to operate and simple in process flow aiming at the polyurethane solidified calcareous sand.
Disclosure of Invention
The invention aims to provide a convenient and feasible preparation method of a triaxial sample of polyurethane solidified calcareous sand, which aims to effectively improve the mechanical behavior of the calcareous sand and provide a new technology and a new idea for the treatment of calcareous sand foundation in island engineering.
In order to achieve the purpose, the specific technical scheme of the invention is as follows:
a preparation method of a polyurethane solidified calcareous sand triaxial sample comprises the following steps:
a. pretreatment of calcareous sand particles: taking out a certain amount of calcareous sand, removing calcareous sand particles with the particle size larger than 2mm, putting the rest calcareous sand particles into a container, injecting distilled water, and carrying out elutriation treatment;
b. drying calcareous sand particles: placing the elutriated calcareous sand particle sample on a steel tray, and placing the elutriated calcareous sand particle sample in a constant-temperature oven for drying treatment;
c. mixing and stirring the calcareous sand and the polyurethane white liquid: placing the dried calcareous sand particles into a container, injecting polyurethane white liquid into the container, and uniformly stirring to obtain a mixture of the calcareous sand and the polyurethane white liquid;
d. adding polyurethane black liquor: injecting polyurethane black liquor with certain quality into a container, and quickly and uniformly stirring to obtain a calcareous sand polyurethane condensate;
e. and (3) compacting and sample preparation in a layered manner: layering and compacting the obtained cured calcareous sand polyurethane in a cylindrical sample preparation device according to the specified dry density to obtain a triaxial sample of the solidified calcareous sand polyurethane;
f. and (3) sample maintenance: and placing the obtained triaxial sample of the polyurethane solidified calcareous sand in a constant temperature and humidity curing box for curing.
Further, in the step a, impurities such as algae residues and mud in the calcareous sands are removed in the elutriation process.
Further, in the step b, the temperature of the constant-temperature oven is 105 ℃, and the drying time is 48 h.
Further, in step c, the stirring time should be less than or equal to 60 s.
Further, in the step d, the mass ratio of the added polyurethane black liquor to the added white liquor is 1: 1.
further, in step d, the stirring time should be less than or equal to 30 s.
Further, in the step e, the diameter of the cylindrical sample preparation device is 3.91cm, the height of the cylindrical sample preparation device is 8cm, the sample is totally divided into five layers to be compacted, the height of each layer is 1.6cm, after one layer is compacted, the surface layer of the sample is scraped by using a soil picking knife, and the preparation interval time of each compacted layer is less than or equal to 20 s.
Further, in the step f, the curing temperature is 25 ℃, the humidity is 90%, and the curing time is 3 days.
Compared with the prior art, the invention has the following beneficial technical effects:
1. the preparation method of the polyurethane-cured calcareous sand triaxial sample provided by the invention can be used for conveniently realizing the calcareous sand curing treatment, effectively improving the mechanical behavior of the calcareous sand and improving the shear strength.
2. The method provided by the invention is oriented to the practical engineering problem, can effectively solve the problems of high brittleness, obvious uneven settlement and the like easily occurring in the calcareous sand foundation, and provides an effective and feasible new technology and a new thought for treating the calcareous sand foundation in the island engineering.
3. The method provided by the invention is convenient to operate, simple in process flow, beneficial to popularization and application of actual engineering and high in actual engineering value.
Drawings
FIG. 1 is a flow chart of a preparation method of a triaxial sample of polyurethane-solidified calcareous sand;
FIG. 2 is a diagram of a three-axis sample of polyurethane cured calcareous sand provided in an embodiment of the present invention;
FIG. 3 is a triaxial shear stress strain plot according to an embodiment of the present invention.
Claims (8)
1. A preparation method of a polyurethane solidified calcareous sand triaxial sample is characterized by comprising the following steps:
a. pretreatment of calcareous sand particles: taking out a certain amount of calcareous sand, removing calcareous sand particles with the particle size larger than 2mm, putting the rest calcareous sand particles into a container, injecting distilled water, and carrying out elutriation treatment;
b. drying calcareous sand particles: placing the elutriated calcareous sand particle sample on a steel tray, and placing the elutriated calcareous sand particle sample in a constant-temperature oven for drying treatment;
c. mixing and stirring the calcareous sand and the polyurethane white liquid: placing the dried calcareous sand particles into a container, injecting polyurethane white liquid into the container, and uniformly stirring to obtain a mixture of the calcareous sand and the polyurethane white liquid;
d. adding polyurethane black liquor: injecting polyurethane black liquor with certain quality into a container, and quickly and uniformly stirring to obtain a calcareous sand polyurethane condensate;
e. and (3) compacting and sample preparation in a layered manner: layering and compacting the obtained cured calcareous sand polyurethane in a cylindrical sample preparation device according to the specified dry density to obtain a triaxial sample of the solidified calcareous sand polyurethane;
f. and (3) sample maintenance: and placing the obtained triaxial sample of the polyurethane solidified calcareous sand in a constant temperature and humidity curing box for curing.
2. The method for preparing the triaxial sample of the polyurethane-solidified calcareous sand as claimed in claim 1, wherein in the step a, impurities such as algae residues and mud in the calcareous sand are removed in the elutriation process.
3. The method for preparing the triaxial sample of the polyurethane-cured calcareous sand according to claim 1, wherein in the step b, the temperature of the constant-temperature oven is 105 ℃ and the drying time is 48 hours.
4. The method for preparing the triaxial sample of the polyurethane-solidified calcareous sand according to claim 1, wherein in the step c, the stirring time is less than or equal to 60 s.
5. The method for preparing the triaxial sample of the polyurethane-cured calcareous sand according to claim 1, wherein in the step d, the mass ratio of the added polyurethane black liquor to the added white liquor is 1: 1.
6. the method for preparing the triaxial sample of the polyurethane-solidified calcareous sand according to claim 1, wherein in the step d, the stirring time is less than or equal to 30 s.
7. The method for preparing the triaxial sample of the polyurethane solidified calcareous sand according to claim 1, wherein in the step e, the diameter of the cylindrical sample preparation device is 3.91cm, the height of the cylindrical sample preparation device is 8cm, the sample is divided into five layers and compacted, the height of each layer is 1.6cm, after one layer is compacted, the surface layer of the sample is scraped by using a soil picking knife, and the preparation interval time of each compacted layer is less than or equal to 20 s.
8. The method for preparing the triaxial sample of the polyurethane-cured calcareous sand according to claim 1, wherein in the step f, the curing temperature is 25 ℃, the humidity is 90%, and the curing time is 3 days.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111361357.9A CN114315228A (en) | 2021-11-17 | 2021-11-17 | Preparation method of polyurethane-cured calcareous sand triaxial sample |
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| CN202111361357.9A CN114315228A (en) | 2021-11-17 | 2021-11-17 | Preparation method of polyurethane-cured calcareous sand triaxial sample |
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| CN114315228A true CN114315228A (en) | 2022-04-12 |
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| CN202111361357.9A Withdrawn CN114315228A (en) | 2021-11-17 | 2021-11-17 | Preparation method of polyurethane-cured calcareous sand triaxial sample |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115075221A (en) * | 2022-07-15 | 2022-09-20 | 中国科学院武汉岩土力学研究所 | Quick curing method for calcareous sand |
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2021
- 2021-11-17 CN CN202111361357.9A patent/CN114315228A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115075221A (en) * | 2022-07-15 | 2022-09-20 | 中国科学院武汉岩土力学研究所 | Quick curing method for calcareous sand |
| CN115075221B (en) * | 2022-07-15 | 2023-03-14 | 中国科学院武汉岩土力学研究所 | Quick curing method for calcareous sand |
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Application publication date: 20220412 |