CN103332885A - Blanc fixe cementitious rock soil-like material and method for making simulative rock from the blanc fixe cementitious rock soil-like material - Google Patents

Abstract

The invention relates to a barite powder cemented rock-soil similar material and a method for making a simulated rock mass, belonging to the technical field of rock-soil material simulation in geomechanical model tests. The similar material consists of barite powder as an aggregate and bentonite as an auxiliary material. And the diluted glue mixed with 107 glue and water constitutes a mixture; the method includes: using similar materials to make water-cement ratio-shear strength f curves, calculating the wet density of similar materials in different batches and using each batch of mixtures to make simulated rock Small block specimens: This similar material has the characteristics of low cost, non-toxic, and easy to process and make small blocks, which can well meet the requirements of similar materials for geomechanical model tests; at the same time, use this similar material to make simulated rock The body does not affect the model masonry process, and the production is rapid, which can greatly speed up the progress of the model test. It is especially suitable for the model test field of small block masonry.

Description

Barite powder cemented rock-soil similar material and method for making simulated rock mass

technical field

The invention belongs to the technical field of simulation technology of rock-soil materials in geomechanical model tests, and in particular relates to a novel rock-soil similar material and a method for making simulated rock masses, which are used for geomechanical model tests involving engineering fields such as water conservancy, transportation, and mining. It is suitable for the simulation of medium and medium geotechnical materials, and is especially suitable for small block model tests.

Background technique

Geomechanical model tests can simulate the characteristics of engineering structures, and can also approximate the influence of geological factors such as rock mass faults on engineering stability, so it plays an extremely important role in the design of water conservancy, mining, tunnels, etc. Applications.

According to the objective requirement of the similarity rate between engineering practice and model test, the geomechanics model test has relatively high requirements on the mechanical properties of similar materials for simulating the dam body and the surrounding foundation rock medium. For example, the geomechanics model test requires that the similarity ratio of all dimensionless quantities (strain, internal friction angle, friction coefficient, Poisson's ratio, etc.) of similar materials be 1, and the elastic modulus, stress-strain curve, strength and so on must meet similar conditions. Therefore, similar materials with low elastic modulus (minimum 2mpa) and high strength and high density are often required for testing; moreover, the geological conditions of the same project are quite different, that is, the elastic modulus and density of geotechnical materials are quite different. The mold span is 2mpa-100mpa; in addition, the production and use of similar materials also have non-toxic, low-cost requirements. Therefore, the research and development of similar materials for geomechanical model tests has always been a research hotspot and difficulty in model tests. Relevant scientific research institutions at home and abroad continue to carry out research and development of similar materials. Various new similar materials emerge in endlessly, but few of them can fully meet these requirements. required material.

In the 1980s, Wuhan University of Water Resources and Electric Power invented a similar material mixed with barite powder, film iron powder and rosin alcohol, referred to as MIB material; the elastic modulus of this material can be adjusted according to the thickness of the film, but The neoprene of the iron powder adhesive contains toluene, which is harmful to the human body. Tsinghua University invented a similar material composed of magnetite concentrate powder, river sand, binder gypsum or cement (NIOS) in the early 21st century. This material has stable properties, large capacity, and low price, but it is dry, The maintenance time is long, and the material cannot be reused. Shandong University applied for iron crystal sand cemented rock-soil similar material and its preparation method in 2005, application number 200510104581.4, publication number CN1792990A, the mechanical properties of this material are relatively good, and the cost is low, but it uses quartz sand as the main bone It is not suitable for fine masonry of small blocks.

Contents of the invention

The purpose of the present invention is to solve the current problem of lacking a similar material that satisfies the similarity requirements of geomechanical model tests and is low-cost, non-toxic and easy to process. A barite powder cemented rock-soil similar material is specially proposed. And the method for making simulated rock mass, this similar material has the characteristics of low cost, non-toxic, easy to process and make small blocks, which can well meet the requirements of similar materials for geomechanical model tests; at the same time, use this similar material to make simulated rock The body does not affect the model masonry process, and the production is rapid, which can greatly speed up the progress of the model test. It is especially suitable for the model test field of small block masonry.

A kind of barite powder cemented rock-soil similar material that the present invention proposes is characterized in that, this similar material is aggregate by barite powder, bentonite is auxiliary material, and the dilute glue that 107 glue mixes with water forms mixture; Wherein, The mass ratio of barite powder, bentonite and diluted glue is 11-13:0.25-0.35:1; the mass ratio of 107 glue to water glue in diluted glue is 1:1.5 to 1:6;

The method for making a simulated rock mass using the above-mentioned similar materials is characterized in that the method comprises the following steps:

1) Determine the water-to-binder ratio of diluted glue by shear test: make 4 groups of cubes with the same density, barite powder, bentonite, and diluted glue in the same mass ratio, but with different mass ratios of 107 glue and water in the diluted glue Each group of small test pieces contains four test pieces with the same mixture ratio and glue ratio; for each group of four test pieces, four different vertical loads are used to conduct direct push method shear tests, and four kinds of test pieces are measured. The ultimate shear force of the test piece under different pressure loads; use the least squares method to fit the vertical compressive stress-ultimate shear stress of the same glue ratio, and obtain the shear strength f (that is, the slope f) of the group of small test pieces ; Then the shear strength f of each group is fitted into different water-cement ratio-shear strength f curves;

2) Use uniaxial compression material test to determine the density-elastic modulus curve of similar materials: 4 batches of mixtures are used, and each batch of mixtures is tested separately for the batch of materials. The specific method is as follows: each batch At least 8 groups of cylindrical specimens with different wet densities were made from the mixed material, and each group of specimens contained 4 identical specimens; after each specimen was dried, a uniaxial compression test was performed, and the 4 test specimens in each group were calculated respectively. The average wet density and average elastic modulus of the piece; according to the test data, the wet density-elastic modulus curve of the batch of mixture specimens is made;

3) Calculate the water-binder ratio and wet density of the simulated materials in each part of the model: Calculate the shear strength and elastic modulus required by the similar materials in each part of the model according to the similar proportions of the original design data and the model test, and then according to steps 1) and 2) Determine the water-binder ratio and wet density of similar materials in batches corresponding to each part of the model based on the test results:

4) Make small block specimens of simulated rock mass: select the corresponding batch of mixture according to the position of the simulated rock mass, and then calculate a The mass of the mixture required for the small block test piece; weigh the mixture of this quality and pour it into the pressure forming machine, and press the mixture into the required wet density small block test piece; after the small block is pressed After drying for 2-3 days, according to the shape of each part of the simulated rock mass, select the corresponding batch of small blocks, and build an experimental model of the simulated rock mass block by block.

Features and effects of the present invention:

This similar material uses barite powder as aggregate, bentonite as auxiliary material, 107 glue and water as binder. Among them, barite powder is used to increase the bulk density of the material; bentonite has an obvious effect on reducing the elastic modulus, and its properties are stable; the diluted glue after watering 107 glue in a certain proportion is used as a binder to ensure the shear strength of the material ; This material is especially suitable for simulating brittle materials such as rock mass and concrete, and can ensure that the two most important factors that affect the simulation effect of similar materials - the shear strength and elastic modulus of similar materials well meet the similarity ratio. After the test, the material can be ground into powder for the next test, saving cost.

When making this material, it is only necessary to change the mass ratio and density of 107 glue and water glue in the diluted glue and the density of the small block specimens simulating rock mass, so that it can simulate a very wide elastic modulus range of rock mass, which can meet the requirements of geological conditions. The mechanical model test simulates various common rock masses and dam materials with different mechanical properties. The material and manufacturing process are particularly suitable for the needs of the small block masonry method, and are easy to cut and convenient for masonry. In addition, this material has the following advantages: low material cost; the model made of this material is not easily damaged by the laboratory environment, has stable chemical and physical properties, and has no toxic and side effects; it is easy to finely simulate small blocks; it can greatly speed up the process of model testing. schedule. The material can be reused without affecting the test accuracy. This similar material is especially suitable for the model test field of small block masonry.

Description of drawings

Figure 1 is a typical strain-stress curve of a similar material of the present invention;

Fig. 2 is the mixture density-elastic modulus curve of the present embodiment.

Detailed ways

Barite powder cemented rock-soil similar material that the present invention proposes and preparation method are described in detail as follows in conjunction with accompanying drawing and embodiment:

The similar material of the present invention is aggregate by barite powder, and bentonite is auxiliary material, and the diluted glue that 107 glues and water mixes constitutes mixture; Wherein, the mass ratio of barite powder, bentonite and diluted glue is 11-13:0.25- 0.35:1; the mass ratio of 107 glue to water glue in diluted glue is 1:1.5 to 1:6;

Similar material manufacturing method of the present invention comprises the following steps:

1) Determine the water-to-binder ratio of diluted glue by shear test: make 4 groups of cubes with the same density, barite powder, bentonite, and diluted glue in the same mass ratio, but with different mass ratios of 107 glue and water in the diluted glue Each group of small test pieces contains four test pieces with the same mixture ratio and glue ratio; for each group of four test pieces, four different vertical loads are used to conduct direct push method shear tests, and four kinds of test pieces are measured. The ultimate shear force of the test piece under different pressure loads; use the least squares method to fit the vertical compressive stress-ultimate shear stress of the same glue ratio, and obtain the shear strength f (that is, the slope f) of the group of small test pieces ; Then the shear strength f of each group is fitted into different water-cement ratio-shear strength f curves;

2) Use uniaxial compression material test to determine the density-elastic modulus curve of similar materials: (the model of geomechanical model test is generally divided into 4 parts, and each part uses the same batch of mixture, that is, the model of geomechanical model test generally shares Use 4 batches of mixtures); adopt 4 batches of mixtures, each batch of mixtures is respectively carried out the material test of this batch, the specific method is as follows: each batch of mixtures is produced at least 8 A group of cylindrical specimens with different wet densities, each group of specimens contains 4 identical specimens; each specimen is subjected to a uniaxial compression test after drying, and the average wet density and the average Elastic modulus; according to the test data, make the wet density-elastic modulus curve of the batch of mixture specimens;

3) Calculate the water-binder ratio and wet density of the simulated materials in each part of the model: Calculate the shear strength and elastic modulus required by the similar materials in each part of the model according to the similar proportions of the original design data and the model test, and then according to steps 1) and 2) Determine the water-binder ratio and wet density of similar materials in batches corresponding to each part of the model based on the test results:

4) Make small block specimens of simulated rock mass: select the corresponding batch of mixture according to the position of the simulated rock mass, and then calculate a The mass of the mixture required for the small block test piece; weigh the mixture of this quality and pour it into the pressure forming machine, and press the mixture into the required wet density small block test piece; after the small block is pressed After drying for 2-3 days, according to the shape of each part of the simulated rock mass, select the corresponding batch of small blocks, and build an experimental model of the simulated rock mass block by block.

Principle of the present invention:

The invention mainly makes the elastic modulus and shear strength of similar materials meet the requirement of similarity ratio. The reasons are as follows:

In the geomechanics model test, the shear strength of the simulated material has a great influence on the test results, and the compressive strength has a certain positive correlation with the shear strength, and its influence on the results is small; so the shear strength is the main simulation of the simulated material. factor. Most of the geomechanics model tests use the overload method to pressurize, that is, the impact of material density on test results is less than that of material elastic modulus, and the elastic modulus and density of materials also have a certain positive correlation; therefore, the present invention does not Directly consider the influence of the actual rock mass density on the test results, and use the same proportion of materials (barite powder, bentonite, diluted glue mass ratio 12:0.3:1), and simulate the difference of the elastic modulus by simulating the density of the material.

This similar material can simulate the rock mass with elastic modulus range of (14mpa-480mpa), bulk density of 1.6-2.2t/m ³ , and compressive strength of 0.1-0.8mpa. The materials are similar (Figure 1 is the typical stress-strain curve of the simulated material, the horizontal axis is the strain value, and the vertical axis is the stress value), which can meet the requirements of the geomechanics model test for various common rock mass and dam materials with different mechanical properties. simulation.

Example

The present invention is illustrated below with a certain arch dam model test, the size similarity ratio of this arch dam model test is 250, the elastic modulus similarity ratio is 250, and the f similarity ratio is 1; each part distribution of the barite powder cemented novel rock mass similar material Ratio: The basic mass ratio of barite powder, bentonite and diluted glue is 12:0.3:1. The method of using barite powder to cement rock-soil similar materials and making simulated rock mass in this embodiment includes using shear test to determine the water-binder ratio of diluted glue, using uniaxial compression material test to determine the density-elastic modulus curve of similar materials, Calculate the water-binder ratio and wet density of the simulated materials for each part of the model, and make 4 parts of the small block specimens that simulate the rock mass.

The arch dam prototype and model test data of the present embodiment are as shown in Table 1:

Arch dam prototype and model test data form of table 1 present embodiment:

1) Determine the water-to-binder ratio of the diluted glue by shear test: make 4 groups of small cubic specimens with the same density, barite powder, bentonite, and diluted glue with the same mass ratio, but with different mass ratios of 107 glue to water, 4 The mass ratios of 107 glue and water in the group of small test pieces were 1:1.5, 1:2.5, 1:3.5, 1:6 respectively, and each group of small test pieces contained four test pieces with the same proportion and water-cement ratio; For each group of four specimens, use four different vertical loads (vertical compressive stresses are 20kpa, 40kpa, 60kpa, 80kpa respectively) to carry out direct push method shear test, and measure the strength of the specimens under four different pressure loads. Ultimate shear resistance; use the least square method to fit the vertical compressive stress-ultimate shear stress of the same water-binder ratio, and obtain the shear strength f (ie slope f) of the small specimens in this group; The shear strength f is fitted into different water-cement ratio-shear strength f curves, as shown in Table 2;

Table 2 Glue/water mass ratio of diluted glue-shear strength f value table

2) Using uniaxial compression material test to determine the density-elastic modulus curve of similar materials: Divide the arch dam and surrounding slope models in the geomechanics model test into 4 parts for each part, and use the same batch of mixture for each part. That is, there are 4 batches of mixtures; for each batch of mixtures, the material test of this batch is carried out separately, the method is as follows: each batch of mixtures is made at least 8 groups of cylindrical test pieces with different wet densities ( The diameter is 3.9cm, the height is 8cm, the wet density is from 2.2-1.8g/cm ³ , the wet density refers to the density of the newly pressed and undried specimen), each group of specimens contains 4 specimens with the same wet density; After the specimens were dried in the sun, the masses were weighed respectively, and the uniaxial compression test was carried out to calculate the average wet density and average elastic modulus of the 4 specimens in each group; according to the test data, the wet density of the batch of mixture specimens was obtained— —Elastic modulus curve, as shown in Table 3 (mixture wet density-elastic modulus value table), Figure 2 (mixture wet density-elastic modulus curve, the horizontal axis is the mixture wet density, and the vertical axis is the elastic modulus) ( The method of making the cylindrical test piece is as follows: use the pressure forming machine to press the mixed mixture into a rectangular parallelepiped test piece of 4cm*4cm*8cm, and then use two iron flat plates with a diameter of 3.9cm to press the test piece. The upper and lower surfaces, and then manually carved with a knife); according to the test data, the wet density-elastic modulus curve of the batch of mixture specimens is made.

Table 3 Mixture wet density-numeric table of elastic modulus

3) Calculate the water-binder ratio and wet density of the simulated materials in each part of the model: Calculate the shear strength and elastic modulus required by similar materials in each part of the model according to the original data of the design institute and the similar ratio of the model test, and then according to 1) and 2) Determine the water-binder ratio and wet density of similar materials in batches corresponding to each part of the model based on the test results:

4) Make small block specimens of simulated rock mass: select the corresponding batch of mixture according to the different parts of the simulated rock mass, mix and stir the mixture evenly according to the specified ratio; determine the wet density and small block size of the simulated material at this part body test piece shape, calculate the quality of the required mixture of a small block test piece; Small blocks of 12 sizes; Among them, 5cm*5cm*8cm is used to build most of the rock mass of the foundation, 16cm*16cm*8cm is used to build the dam body and boundary, and small blocks of other sizes are used for detailed Part masonry): Weigh the calculated mass of the mixture and pour it into the pressure forming machine, press the mixture into a small block test piece with the required wet density, and proceed to the next small block test piece;

After the small block test piece is pressed and formed, it is aired for 2-3 days, and then it can be built into different parts of the solid model according to the shape of the small block test piece.

Claims (2)

1. a ground barium sulfate cement rock soil phase is characterized in that like material this analog material is aggregate by ground barium sulfate, and wilkinite is subsidiary material, and the dilution glue of 107 glue and water mixing constitutes compound; Wherein, the mass ratio of ground barium sulfate, wilkinite and dilution glue is 11-13:0.25-0.35:1; The mass ratio of the glue of 107 glue and water is that 1:1.5 is to 1:6 in the dilution glue.

2. adopt the method for analog material making simulation rock mass according to claim 1, it is characterized in that this method may further comprise the steps:

1) adopt shearing test to determine the water-cement ratio of dilution glue: it is identical to make 4 groups of density, the quality proportioning of ground barium sulfate, wilkinite, dilution glue is also identical, but 107 glue and quality are than different cubes small specimens in the dilution glue, and every group of small specimen contains the test specimen of four same mixture material proportionings and cement ratio; To four test specimens of every group, use four kinds of vertical loads of difference to carry out straight pushing manipulation shear test respectively, measure the ultimate shearing resistance of test specimen under four kinds of different pressures load situation; Use the vertical compressive stress-ultimate shear stress of the identical cement ratio of least square fitting, obtain the slip resistance f (being slope f) of this group small specimen; Slip resistance f to each group fits to different water-binder ratios-slip resistance f curve again;

2) adopt the uniaxial compression testing of materials to determine analog material density-bullet modular curve: to adopt 4 batches compound, the compound of each batch carries out the testing of materials of this batch respectively, concrete grammar is as follows: the compound of each batch is produced the cylindric test specimen of at least 8 group DIFFERENT WET density, and every group of test specimen contains 4 identical test specimens; Carry out uniaxial compression test after each test specimen dried, calculate the average wet density and the average mould that plays of respectively organizing 4 test specimens respectively; According to testing data, make the wet density of this batch compound test specimen---play modular curve;

3) the test-results glue of the every position of computation model simulation material wet density when: calculate slip resistance that each position analog material of model requires, play mould, again according to step 1) and 2 according to the similar proportion of design starting material and model trial) is determined analog material water-cement ratio and the wet density at corresponding batch of each position of model:

4) make the small blocks test specimen of simulation rock mass: select corresponding batch compound for use according to the position of simulation rock mass, again according to wet density and the small blocks test specimen shape of the simulation rock mass calculation requirement at this position, calculate the quality of a required compound of small blocks test specimen; The compound that takes by weighing this quality is poured in the compression molding press, this compound is pressed into the wet density small blocks test specimen of described requirement; After the small blocks compacting finishes, after airing 2-3 days, according to the shape of each parts of simulation rock mass, select the small blocks of respective batch for use, block-by-block is built into the experimental model of simulation rock mass by laying bricks or stones.

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