阅读说明：本技术 一种用于高拱坝动力模型试验的相似材料及其制备方法 (Similar material for high arch dam power model test and preparation method thereof ) 是由 曹茂森 魏庆阳 李翼飞 胡帅涛 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种用于高拱坝动力模型试验的相似材料及其制备方法,涉及模型试验领域。所述相似材料的原材料包括：重晶石砂、重晶石粉、粉煤灰、水泥和水,所述原材料按质量比为：重晶石砂45-55份、重晶石粉25-35份、粉煤灰7-15份、水泥1-5份和水6-13份。制备时,先将重晶石砂和重晶石粉混合,然后再将粉煤灰和水泥混合并干拌,水分为两次加入。这种相似材料具有初凝时间长,力学参数的可调节范围较广的特点,原材料来源广泛、无毒无害、价格低廉,在高拱坝动力模型试验领域具有大规模应用的前景。(The invention discloses a similar material for a high arch dam dynamic model test and a preparation method thereof, and relates to the field of model tests. The raw materials of the similar material comprise: the material comprises the following raw materials in percentage by mass: 45-55 parts of barite sand, 25-35 parts of barite powder, 7-15 parts of fly ash, 1-5 parts of cement and 6-13 parts of water. During preparation, barite sand and barite powder are mixed, then fly ash and cement are mixed and dry-mixed, and water is added twice. The similar material has the characteristics of long initial setting time and wide adjustable range of mechanical parameters, has wide raw material source, no toxicity, no harm and low price, and has a large-scale application prospect in the field of high arch dam power model tests.)

1. A similar material for a dynamic model test of a high arch dam, wherein raw materials for preparing the similar material comprise: barite sand, barite powder, fly ash, cement and water; wherein the mass ratio of the raw materials is as follows: 35-55 parts of barite sand, 25-45 parts of barite powder, 7-15 parts of fly ash, 1-6 parts of cement and 6-13 parts of water.

2. A similar material for high arch dam dynamic model test as claimed in claim 1, wherein the barite sand has a particle size of 2-4mm and specific gravity of 4.0-4.2g/cm³。

3. The similar material for the dynamic model test of the high arch dam as claimed in claim 1, wherein the barite powder has a particle size of 0.1-0.2mm and a specific gravity of 4.3-4.5g/cm³。

4. A similar material for high arch dam dynamic model test as claimed in claim 1, wherein the quality grade of the fly ash is two grade, and the fineness requirement is that the residue of the sieve with 45 μm square hole is not more than 25%.

5. A similar material for high arch dam dynamic model test as claimed in claim 1, wherein said cement is M32.5 cement.

6. A method for preparing a similar material for a high arch dam dynamic model test according to claim 1, comprising the steps of:

step 1, weighing barite sand, barite powder, fly ash, cement and water with corresponding mass respectively by using an electronic scale according to the mass ratio of raw materials;

step 2, pouring the barite sand, the barite powder, the fly ash and the cement weighed in the step 1 into a stirrer;

step 3, starting the stirrer for dry mixing, and uniformly stirring the materials poured in the step 2; pouring half of the water weighed in the step 1 into the stirrer, and stirring; then pouring the rest half amount of the water weighed in the step 1 into the stirrer, and stirring again;

step 4, filling the mixture uniformly stirred in the step 3 into an inner surface layer, uniformly coating the mixture on an engine oil plastic mould for forming, vibrating on a vibrating table until the surface layer of the test piece uniformly discharges water, and stopping vibrating;

step 5, standing the material formed in the step 4 for 24 hours at normal temperature and normal humidity, demolding by using an air pump with the pressure not more than 0.3Mpa, obtaining a test piece after demolding, and maintaining the test piece for 48 hours;

and 6, after the maintenance of the test piece is finished, testing the mechanical property of the test piece on an electronic universal testing machine with the range not greater than 100KN, and acquiring the mechanical property parameters of the similar material prepared under the mixing ratio.

7. The preparation method according to claim 6, wherein in the step 2, the weighed barite sand and barite powder are added into the stirrer, and then the fly ash and the cement are poured into the stirrer simultaneously.

8. The preparation method according to claim 6, wherein the specific process of step 3 is to start the stirrer, dry-mix the mixture for 3 minutes at a rotation speed of 80rad/min, and stir the poured material in step 2 uniformly; pouring half amount of the water weighed in the step 1 into the stirrer, and stirring for 2 minutes at a speed of 50 rad/min; the remaining half amount of the water weighed in step 1 was poured into the mixer and stirred again for 3 minutes at a speed of 60 rad/min.

9. The method according to claim 6, wherein the parameters of the vibration table in step 4 are a vibration frequency of 50-60Hz and an amplitude of 1-2 mm.

10. The method according to claim 6, wherein the curing conditions after the mold release in step 5 are curing in an environment having a temperature of 18 to 22 ℃ and a humidity of 93 to 97%.

Technical Field

The invention relates to the field of model tests, in particular to a similar material for a high arch dam dynamic model test and a preparation method thereof.

Background

With the further development of hydropower resources in China, a plurality of arch dams with different heights of 200 meters or even 300 meters are being built or planned to be built in the southwest region of China. In the areas, the earthquake probability is high, the intensity is high, and the earthquake resistance problem is one of the most challenging problems in the construction process of the high arch dam. The anti-seismic problem of the high arch dam is researched, the whole process behavior of the dam under the action of an earthquake is often required to be observed, and therefore, the dynamic model test based on the vibrating table is an important method for researching the mechanical behavior and the dam body behavior of the high arch dam under the action of earthquake load.

The dynamic model test is to reduce the prototype engineering to the physical model that the laboratory can bear on the premise of satisfying the similar conditions, and to reverse the rules in the prototype engineering by researching the rules of the model. For projects such as high arch dams, the seismic problem needs to be researched to meet the similarity criterion of gravity and inertia force, namely lambda_ρλ_L＝λ_EWherein λ is_ρDensity scale, λ, representing prototypes and models_EIntensity scale, λ, representing prototypes and models_LRepresenting the geometric scale of the prototype and model. The difficulty in developing the high arch dam model test is that the geometric scale of the prototype and the model is particularly large, so that the requirements of similar materials on low strength and high density are difficult to meet by common materials.

At present, rock mass similar materials with better performance appear in the field of geotechnical engineering, but the scale difference of a prototype and a model in the geotechnical engineering is far less than that in the field of high arch dams, and raw materials for preparing the similar materials are not easy to obtain and have higher cost. Not only few similar materials used for high arch dam model tests are difficult to completely meet the requirements of similar conditions, so that the development of the high arch dam dynamic model test similar material with wide material source and simple manufacturing process is extremely urgent.

Disclosure of Invention

Based on the defects of the prior art, the technical problem to be solved by the invention is to provide a similar material for a high arch dam power model test and a preparation method thereof, so as to meet the requirements of the high arch dam power model test based on a vibration table.

In order to solve the technical problems, the invention provides a similar material for a high arch dam dynamic model test and a preparation method thereof, and the specific technical scheme is as follows:

the invention provides a material for preparing a high arch dam, which comprises the following raw materials: barite sand, barite powder, fly ash, cement and water. The mass ratio of the raw materials is as follows: 35-55 parts of barite sand, 25-45 parts of barite powder, 7-15 parts of fly ash, 1-6 parts of cement and 6-13 parts of water.

Furthermore, the raw material for preparing the high arch dam similar material provided by the invention has the advantages that the grain diameter of the barite sand is 2-4mm, and the specific gravity is 4.0-4.2g/cm³。

Furthermore, the raw material for preparing the high arch dam similar material provided by the invention has the advantages that the grain diameter of the barite powder is 0.1-0.2mm, and the specific gravity is 4.3-4.5g/cm³。

Furthermore, the raw material for preparing the high arch dam similar material provided by the invention has the quality grade of two-grade fly ash, and the fineness requirement that the residue is not more than 25% according to a 45-micron square-hole sieve.

Further, the invention provides a raw material for preparing a high arch dam similar material, and the cement is M32.5 cement.

The invention also discloses a preparation method of the similar material for the high arch dam dynamic model test, which comprises the following steps:

step 1, weighing barite sand, barite powder, fly ash, cement and water with corresponding mass according to weight proportion by using an electronic scale.

And 2, pouring the barite sand, the barite powder, the fly ash and the cement weighed in the step 1 into a stirrer.

Step 3, starting the stirrer for dry mixing, and uniformly stirring the materials poured in the step 2; pouring half of the water weighed in the step 1 into a stirrer and stirring; then, the remaining half of the water weighed in step 1 was poured into the mixer and stirred again.

And 4, filling the mixture uniformly stirred in the step 3 into an inner surface layer uniformly-coated engine oil plastic mould, vibrating on a vibrating table until the surface layer of the test piece uniformly discharges water, and stopping vibrating.

And 5, standing the material formed in the step 4 for 24 hours at normal temperature and normal humidity, demolding by using an air pump with the pressure not more than 0.3Mpa, demolding to obtain a test piece, and curing the test piece for 48 hours.

And 6, after the maintenance of the test piece is finished, testing the mechanical property of the test piece on an electronic universal testing machine with the range not greater than 100KN, and acquiring the mechanical property parameters of the similar material prepared under the mixing ratio.

Further, the preparation method comprises the step 2 of firstly adding the weighed barite sand and barite powder into a stirrer, and then simultaneously pouring the fly ash and the cement into the stirrer.

Further, step 3 of the preparation method is that the stirrer is started, and is dry-mixed for 3 minutes at the speed of 80rad/min, and the materials poured in the step 2 are uniformly stirred; pouring half of the water weighed in the step 1 into a stirrer, and stirring for 2 minutes at a speed of 50 rad/min; the remaining half of the water weighed in step 1 was poured into the mixer and stirred again for 3 minutes at a speed of 60 rad/min.

Furthermore, in the step 4 of the preparation method, the parameters of the vibration table are that the vibration frequency is 50-60Hz, and the amplitude is 1-2 mm.

Further, the curing condition after demolding in step 5 of the preparation method is curing in an environment with the temperature of 18-22 ℃ and the humidity of 93% -97%.

By adopting the technical means, compared with the prior art, the invention has the following advantages:

1. the barite sand is used as a coarse aggregate, the barite powder is used as a fine aggregate, and the specific gravity of the two materials reaches 4.0g/cm³Therefore, the prepared similar material has higher density and can fully meet the requirements of similar conditions.

2. The cementing material is low-strength cement with the mark M32.5, and the dosage of the low-strength cement is larger than that of high-strength cement, so that the defect of large difference of different areas of the mixture caused by uneven stirring is avoided. The introduction of fly ash replaces a portion of the cement and therefore similar materials are produced which have very low strength whilst maintaining good workability.

3. The initial setting time of the similar material prepared by the invention is more than 60 minutes, and compared with the traditional materials used for model tests, such as gypsum and the like, the initial setting time of which is very short, the similar material prepared by the invention has enough forming time for carrying out the model tests.

4. The compressive strength of the similar material prepared by the invention is between 0.2 and 5MPa, the tensile strength is between 5 and 500KPa, the elastic modulus is between 8 and 400MPa, the adjustable range of mechanical parameters is wider, and the applicability to different engineering requirements is strong.

5. The raw materials used by the invention have wide sources, no toxicity, no harm and low price, and have the prospect of large-scale application.

Drawings

Fig. 1 is a diagram of the raw materials used in the present invention for making a high arch dam-like material.

Fig. 2 is a failure pattern diagram of a test piece of a high arch dam-like material prepared in the present invention.

Fig. 3 is a graph showing the splitting and compression curves of a crowned dam-like material in example 1 of the present invention.

Fig. 4 is a graph showing the splitting and compression curves of a crowned dam-like material in example 2 of the present invention.

Detailed Description

The present invention is further described with reference to the following specific embodiments and the attached drawings, it is to be understood that these embodiments are merely illustrative of the present invention and not restrictive of the scope of the invention, and that various equivalent modifications of the present invention by those skilled in the art after reading the present invention fall within the scope of the appended claims:

the invention provides a high arch dam similar material for a dynamic model test and a preparation method thereof, and as shown in figure 1, barite sand, barite powder, fly ash, cement and water are selected as raw materials. According to the requirements of a specific model test, the high arch dam similar material meeting the physical and mechanical properties under the similar requirements is obtained by adjusting the mass mixing ratio of the raw materials. The raw materials for preparing the high arch dam similar material comprise the following components in parts by mass: 35-55 parts of barite sand and barite25-45 parts of stone powder, 5-15 parts of fly ash, 1-6 parts of cement and 6-13 parts of water. Wherein the barite sand has a particle size of 2-4mm and a specific gravity of 4.0-4.2kg/m³(ii) a The barite powder has a particle size of 0.1-0.2mm and a specific gravity of 4.3-4.5kg/m³(ii) a The quality grade of the fly ash is two grades, and the fineness requirement is that the residue is not more than 25 percent according to a 45-micron square-hole sieve; the cement is M32.5 cement.

Example 1:

weighing 51.1 parts of barite sand, 25.6 parts of barite powder, 7.9 parts of fly ash, 5.6 parts of cement and 9.8 parts of water according to the weight proportion by using an electronic scale; firstly, pouring the weighed barite sand into a stirrer, then pouring the weighed barite sand into the stirrer, and finally pouring the weighed fly ash and cement into the stirrer simultaneously; starting the stirrer, dry-mixing the barite sand, the barite powder, the fly ash and the cement material poured into the stirrer for 3 minutes at the speed of 80rad/min, pouring half of the weighed water into the stirrer, stirring for 2 minutes at the speed of 50rad/min, and finally pouring the remaining half of the weighed water into the stirrer, and stirring for 3 minutes again at the speed of 60 rad/min; and (3) putting the uniformly stirred mixture into a plastic mould with an inner surface layer uniformly coated with engine oil, vibrating on a vibrating table according to the vibration frequency of 50-60Hz and the amplitude of 1-2mm until the surface layer uniformly discharges water, and stopping vibrating. Standing the formed material at normal temperature and humidity for 24 hours, demoulding by using an air pump with the pressure not more than 0.3Mpa, and curing for 48 hours in an environment with the temperature of 18-22 ℃ and the humidity of 93-97 percent after demoulding. And after the maintenance of the test piece is finished, performing mechanical property test on the test piece on an electronic universal testing machine with the range not greater than 100KN, and acquiring the mechanical property parameters of the prepared similar material at the mixing ratio. Fig. 2 is a view showing a failure mode of a prepared test piece of the high arch dam-like material.

Under the mass mixing ratio, the mechanical properties of the finally tested similar material are as follows: the density was 2627.50kg/m³The compression strength is 2.05MPa, the tensile strength is 139.40KPa, the elastic modulus is 162.90MPa, the initial setting time is 80min, and the method is suitable for model test of a 300-meter high arch dam cast by C30 concrete in a prototype under the condition of strictly controlling the similarity of the elastic modulusAnd (6) testing. Referring to fig. 3, the comparative materials have a distinct thread elastic phase during cleaving and a better approximate thread elastic phase during compression. The splitting and compressive stress-strain curves of the similar material are very similar to the stress-strain curve of an actual concrete material, and the similar material has good similarity.

Example 2:

weighing 36.5 parts of barite sand, 36.5 parts of barite powder, 14.2 parts of fly ash, 1.4 parts of cement and 11.4 parts of water by using an electronic scale; firstly, pouring the weighed barite sand into a stirrer, then pouring the weighed barite sand into the stirrer, and finally pouring the weighed fly ash and cement into the stirrer simultaneously; starting the stirrer, dry-mixing the barite sand, the barite powder, the fly ash and the cement material poured into the stirrer for 3 minutes at the speed of 80rad/min, pouring half of the weighed water into the stirrer, stirring for 2 minutes at the speed of 50rad/min, and finally pouring the remaining half of the weighed water into the stirrer, and stirring for 3 minutes again at the speed of 60 rad/min; and (3) putting the uniformly stirred mixture into a plastic mould with an inner surface layer uniformly coated with engine oil, vibrating on a vibrating table according to the vibration frequency of 50-60Hz and the amplitude of 1-2mm until the surface layer uniformly discharges water, and stopping vibrating. Standing the formed material at normal temperature and humidity for 24 hours, demoulding by using an air pump with the pressure not more than 0.3Mpa, and curing for 48 hours in an environment with the temperature of 18-22 ℃ and the humidity of 93-97 percent after demoulding. And after the maintenance of the test piece is finished, performing mechanical property test on the test piece on an electronic universal testing machine with the range not greater than 100KN, and acquiring the mechanical property parameters of the prepared similar material at the mixing ratio.

Under the mass mixing ratio, the mechanical properties of the finally tested similar material are as follows: the density was 2512.33kg/m³The compression strength is 0.38MPa, the tensile strength is 7.56KPa, the elastic modulus is 9.54MPa, the initial setting time is 65min, and the method is suitable for a model test of a 200-meter high arch dam cast by C30 concrete in a prototype under the condition of strictly controlling similar compression strength. Referring to FIG. 4, the comparative materials have a distinct linear elastic phase during cleaving and also have a better linear elastic phase during compressionApproximately the linear elastic phase. The splitting and compressive stress-strain curves of the similar material are very similar to the stress-strain curve of an actual concrete material, and the similar material has good similarity. By combining the embodiment 1 and the embodiment 2, the similar material has the advantage of wide material property adjusting range compared with other existing materials, and has a wider application prospect.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.