A process for making a model of a village house based on similarity theory

Abstract

The application discloses a kind of village house experimental model manufacturing process based on similarity theory, based on the actual size of mining area village house, structure and house building material, experimental platform and model design requirement, determine geometric similarity ratio, mechanical similarity ratio and dynamics similarity ratio parameter;Based on the experimental theory of mining subsidence science similar material model, determine the experimental material of simulated house, use mold to make house model brick of different material proportioning;Mechanical test experiment is carried out to house model brick, and the model brick of the optimal experimental material proportioning is selected as the experimental preferred model brick;Select the cementing material between house model brick, make the masonry model of house model brick, determine the optimal cementing material between house model brick;According to the actual situation of house, according to the geometric similarity ratio and dynamics similarity ratio of house whole, make house model.It lays the experimental foundation for the deformation and damage characteristics research of building in mining influence area, and provides reference for house damage mechanism research and reinforcement maintenance.

Description

Technical Field

[0001] This invention relates to the field of surface movement and deformation simulation technology. Specifically, it relates to a process for fabricating experimental models of village houses based on similarity theory. Background Technology

[0002] Coal resources, as my country's primary energy source, have played a vital role in the process of industrial modernization. However, large-scale coal mining has led to widespread surface subsidence, causing significant disturbance and damage to land resources and surface buildings in mining areas. The safety of these buildings directly impacts the quality of life for people living in mining areas.

[0003] Current research on building damage experiments mainly includes similarity simulation and numerical simulation. Traditional similarity material simulation experiments are devices used to simulate the movement of rock strata and the ground surface. They can only simulate the movement and deformation of rock strata and the ground surface caused by different geological mining conditions and working conditions such as coal seam mining height and width. The geometric scale of similar models is generally 1:200 to 1:800, which is relatively small and has low simulation accuracy, and is usually only used for qualitative analysis. Numerical simulation in model damage studies oversimplifies the loading, deformation, and structure of buildings, and the selection of calculation methods and parameters also has considerable uncertainty, making it difficult to meet the needs of guiding practical mining operations.

[0004] To study the impact of surface movement and deformation on surface buildings and structures, and to better guide mining practices, the most effective research method currently is to conduct simulation experiments using similar building models. Patent CN201920009018.6 has developed a surface movement and deformation simulation experimental platform that can generate three-dimensional surface movement and deformation to simulate the impact of this deformation on buildings in mining areas, with a geometric scale of 1:10 to 1:100. However, research on the building model fabrication process and procedures remains lacking. Therefore, this patent proposes a village building experimental model fabrication process based on similarity theory.

[0005] The invention, disclosed in CN107067944A, is titled "A Real Estate Model Structure and Its Manufacturing Process." It describes a house model structure and its manufacturing process, including a base plate and a foundation model. The foundation models are arranged regularly on the base plate. After silicone rubber slurry is poured into and cured, a mold cavity with the same shape as the foundation model is formed. The process involves preparing the molding materials, preparing the concave mold, preparing the resin slurry, producing the semi-finished product, and painting the model. Real estate models made using this molding method can be mass-produced and are economical. However, while this house model is primarily made using molding and can be scaled down to a certain extent, it does not consider the similarity to the actual house in terms of materials and dynamics. Therefore, it cannot ensure that the simulated experimental platform of the house matches the actual structure's dynamic response and deformation state during construction.

[0006] The invention, with publication number CN114863787A, is titled "A Solid Architectural Model and Its Manufacturing Process." The solid architectural model is manufactured using 3D printing, facilitating assembly and allowing for flexible positioning to achieve a 360-degree display. This solves the problem of existing solid models having a limited display area due to their fixed installation. However, this solid architectural model manufacturing process, based on 3D printing technology, is primarily used for display purposes in urban construction, real estate development, and commercial housing sales. It does not consider the physical and mechanical properties of building materials and structures, making it unsuitable for scientific research on the impact of mining-induced damage to buildings in mining areas. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to provide a process for making a village house experimental model based on similarity theory. Combining the actual size, structure and experimental platform parameters of houses in the mining area, the optimal experimental material ratio and brick bonding material are determined based on similarity theory to make a similar village house experimental model, so as to ensure that the simulation results of the house damage experimental platform are consistent with the physical phenomena such as the dynamic response and deformation state of the actual structure during the mining process.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] A process for constructing an experimental model of village houses based on similarity theory includes the following steps:

[0010] (1) Based on the actual size, structure and building materials of village houses in the mining area, as well as the design requirements of the experimental platform and model, determine the parameters of geometric similarity ratio, mechanical similarity ratio and dynamic similarity ratio;

[0011] (2) Based on the experimental theory of similar material models in mining subsidence science, the experimental materials for simulating houses are determined, and house model bricks with different material ratios are made using molds according to the geometric similarity ratio.

[0012] (3) Conduct mechanical testing experiments on the bricks of the house model, compare the elastic modulus and Poisson's ratio mechanical parameters of the house model and the house prototype, calculate the degree of conformity of mechanical parameters, determine the optimal experimental material ratio, and select the model bricks with the optimal experimental material ratio as the preferred model bricks for the experiment.

[0013] (4) Select the bonding material between the bricks of the house model, make a masonry model of the house model bricks, and conduct mechanical experiments to compare it with the house prototype to determine the optimal bonding material between the bricks of the house model.

[0014] (5) Based on the actual situation of the house, make a house model according to the overall geometric similarity ratio and dynamic similarity ratio of the house.

[0015] The above-mentioned village house experimental model making process based on similarity theory, in step (1), the actual size and structure of the village houses are investigated on site, and the physical and mechanical parameters of the bricks and the mechanical properties of the masonry structure are obtained by consulting the literature;

[0016] The building's structural details include: structural type and materials, whether it is a single-story or multi-story building, and whether it has ring beams and structural columns;

[0017] Physical and mechanical parameters of bricks: elastic modulus and Poisson's ratio; based on the types of bricks surveyed on site, consult the corresponding elastic modulus and Poisson's ratio of the bricks.

[0018] Mechanical properties of masonry structures: tensile strength, compressive strength and shear strength of the structure; based on on-site investigation and consultation of relevant data, the mechanical properties of village house masonry structures were obtained.

[0019] The above-mentioned village house experimental model making process based on similarity theory, in step (1), according to the size and structure of the house survey, the experimental platform and model design requirements, calculate and determine the similarity ratio parameters, including geometric similarity, mechanical similarity and dynamic similarity;

[0020] Geometric similarity requires that the model and the on-site building have similar geometry, with length, width, height, and thickness all maintaining a certain proportion; the geometric similarity ratio 'a' is determined based on the dimensions of the prototype building and the simulation test bench, the specific research objectives, and the accuracy requirements. l ;

[0021]

[0022] In the formula: a l The geometric similarity ratio; l M For model dimensions and length; l H The dimensions and length of the houses in the mining area.

[0023] The above-mentioned village house experimental model manufacturing process based on similarity theory means that the physical and mechanical properties of the house prototype and the brick model, as well as the masonry structure, remain similar.

[0024] Mechanical similarity of model bricks: three similarity conditions are met: similarity ratio of stress, similarity ratio of elastic modulus, and similarity of Poisson's ratio of model bricks;

[0025] Stress in the model brick: The ratio of the stress in the strain curve of the model brick to the stress of the prototype brick is equal to the ratio of its geometric dimensions, i.e., a. σ =a l And the strain values ​​are the same, i.e., a ε =ε M / ε H =1; where: a σ The stress ratio between the model bricks and the prototype bricks of the houses in the mining area; a εε represents the ratio of the strain values ​​of the model bricks to the prototype bricks of the mining area houses. M ε represents the strain value of the model brick; H The strain value of the bricks in the houses in the mining area;

[0026] Similar elastic modulus: The elastic modulus of the model bricks and the prototype bricks of the mining area houses are the same or similar, that is...

[0027] Where E M E represents the elastic modulus of the model brick. H a is the elastic modulus of the bricks used in the mining area. E Elastic modulus ratio;

[0028] Poisson's ratio: The model bricks and the prototype bricks of the mining house have the same Poisson's ratio, that is...

[0029] μ M Where is the Poisson's ratio of the model bricks; μ H Let a be the Poisson's ratio of the bricks used in the mining area's houses. μ This is the ratio of Poisson's ratio;

[0030] Masonry structures share mechanical similarities: similar tensile strength, compressive strength, and shear strength.

[0031] The above-mentioned village house experimental model fabrication process based on similarity theory achieves dynamic similarity: all forces between the masonry house model and the on-site house prototype remain similar; the dynamic similarity ratio a k :

[0032]

[0033] Where, γ M The bulk density of the mixed material in the model is kg / m³. 3 ;γ H The bulk density of the prototype composite material is kg / m³. 3 ;l M For model dimensions and length; l H The dimensions and length of the houses in the mining area.

[0034] The above-mentioned process for constructing a village house experimental model based on similarity theory includes the following in step (2):

[0035] (2-1) Based on the geometric similarity ratio obtained in step (1), a brick mold that conforms to the geometric similarity ratio is made; in the brick mold, the length, width, and height of each brick unit satisfy l=L×a l l and L represent the dimensions of the model bricks and the dimensions of the bricks used to build houses in the mining area, respectively; a l It is the geometric similarity ratio;

[0036] (2-2) Preparation of experimental materials for model bricks: The experimental materials for the model are one or more of lime, cement, red clay and gypsum. The composition and ratio of different experimental materials are selected according to the simulation to adjust the overall strength of the model bricks.

[0037] (2-3) Making model bricks: Mix experimental materials with water in different proportions, and use brick molds to make house model bricks with different material ratios; the specific method for making model bricks is as follows: First, mix the selected model experimental materials with water thoroughly and stir until it becomes a paste, then pour it into the mold, smooth the surface of the mold and ensure that there are no air holes or other impurities in the middle, and let it air dry in a ventilated place; after it is completely dry, carefully take out the small bricks one by one to obtain model bricks with different mechanical strengths.

[0038] The above-mentioned village house experimental model making process based on similarity theory, in step (3), mechanical experiments are conducted on model bricks with different material ratios to obtain the stress-strain curves, elastic modulus and Poisson's ratio of the model bricks; and the actual physical and mechanical properties of the house prototype bricks are compared to determine the degree of conformity between the mechanical parameters of the model bricks under each material ratio condition and the house prototype bricks, to determine the optimal experimental ratio of the material for making the house model bricks, and to select the model bricks made with this material ratio as the preferred model bricks for the experiment;

[0039] The formula for calculating the degree of conformity (k) between the mechanical parameters of the model bricks and the prototype bricks of the house is as follows:

[0040]

[0041] In the formula, k represents the degree of conformity of the mechanical parameters; the smaller the value, the higher the similarity of the mechanical properties between the model bricks and the prototype bricks of the house; E M E represents the elastic modulus of the model brick. H μ is the elastic modulus of the bricks used in mining area houses. M μ is the Poisson's ratio of the model bricks. H ε is the Poisson's ratio of the bricks used in the mining area's houses; M ε represents the strain value of the model brick; H The strain value is the value of the bricks in the houses in the mining area.

[0042] The above-mentioned process for constructing a village house experimental model based on similarity theory includes the following steps in step (4):

[0043] (4-1) Select the bonding material between the bricks and make a masonry wall from the model bricks; the bonding material between the bricks is one or more of the following: paste, clay, glass glue, alcohol glue, fabric glue and cement;

[0044] (4-2) Control the thickness of the bonding material; the thickness of the bonding material between bricks is 1-3 mm;

[0045] (4-3) Conduct mechanical tests on the masonry structure of the model bricks bonded together, and compare the compressive strength R between the prototype house and the model masonry. 压 Tensile strength R 拉 and shear strength τ 剪 Determine the optimal bonding material; conduct mechanical tests in accordance with the "Technical Standard for On-site Testing of Masonry Engineering";

[0046] (4-4) If the on-site building has ring beams and structural columns, the corresponding model structure should be added to the masonry structure before relevant mechanical tests are conducted. During the simulation, depending on the strength of the on-site building structure, iron wire, bamboo sticks or grass stems should be added to the cement and lime mixture to simulate the ring beams and structural columns.

[0047] The above-mentioned process for constructing a village house experimental model based on similarity theory includes the following steps in step (5):

[0048] (5-1) Based on the house prototype, the optimal masonry bonding material, and the geometric similarity ratio, the model house size is calculated. The model bricks are stacked to make a preliminary village house model.

[0049] (5-2) Based on the principle of dynamic similarity, determine whether the model house needs counterweight.

[0050] The above-mentioned village house experimental model making process based on similarity theory, according to the principle of dynamic similarity, determines whether the house model needs counterweight and finally completes the house model making:

[0051] If m M =m H a k Then no counterweight is needed;

[0052] If m M ≠m H a k Therefore, counterweights are needed; the counterweights are evenly applied to the roof or eaves, and the mass of the counterweights is Δ = m. H a k -m M ;

[0053] In the formula, a k For the dynamic similarity ratio, m H The total weight of the prototype house is m. M This refers to the overall weight of the model house.

[0054] The technical solution of the present invention achieves the following beneficial technical effects:

[0055] In view of the current lack of research on the theory and technology of house model making for experimental experiments on damage to houses in mining villages, this invention proposes a village house experimental model making process based on similarity theory and combined with relevant mechanical experiments, including the optimized proportioning and making of model brick materials and the selection process of masonry bonding materials.

[0056] This invention provides a process for fabricating village house experimental models based on similarity theory. Primarily based on the actual house structures in mining areas and experimental platform parameters, combined with similarity theory, the optimal material ratio of the bricks and the masonry bonding material for the experimental model were determined for fabricating the house similarity model. This fabrication process effectively solves the problems of existing house model fabrication processes and procedures in mining area similarity simulation experiments, laying an experimental foundation for the study of building deformation and damage characteristics in mining-affected areas, and providing a reference for the study of house damage mechanisms and reinforcement maintenance.

[0057] In addition to considering the geometric similarity ratio, this application also considers the mechanical similarity ratio between the house prototype and the brick model, and further studies the mechanical and dynamic similarity of the masonry structure after the model bricks are assembled.

[0058] The study investigated the compatibility of parameters such as stress-strain, elastic modulus, and Poisson's ratio of house model bricks with different material ratios. A large amount of experimental data was collected, laying the foundation for exploring the optimal material ratio of model bricks for different types of village houses. At the same time, it is also possible to simulate complex types of village houses by adjusting the combination position of model bricks with different material ratios (for example, in some cases, the structure of the house itself is complex, and the physical and mechanical properties and structure of its upper and lower parts have changed, which can be simulated by adjusting the material ratio and combination method of the model bricks).

[0059] More importantly, this application addresses the impact of the bonding material between the model bricks on mechanical properties. Existing 3D printing or monolithic molding technologies do not require consideration of the bonding material between model bricks. This application selects the optimal brick bonding material by testing and comparing the compressive strength, tensile strength, and shear strength between the prototype house and the model masonry. Furthermore, it considers special house structures with ring beams and structural columns, incorporating wire, bamboo skewers, or grass stems to simulate these structures, thereby maximizing the simulation of actual village houses and laying the foundation for accurate results in subsequent building damage experiments. Attached Figure Description

[0060] Figure 1 Brick-concrete structure village houses in Fengfeng Mining District, Handan City, Hebei Province;

[0061] Figure 2 The manufacturing process of house models;

[0062] Figure 3Mechanical parameters of the house model;

[0063] Figure 4 The experimental simulation diagram shows the development of cracks in the building. A represents the numerical software simulation process, and b represents the model experimental platform simulation process. Detailed Implementation

[0064] The process for constructing an experimental model of village houses based on similarity theory includes the following steps:

[0065] I. Based on the actual dimensions, structure, building materials, and experimental platform and model design requirements of village houses in the mining area, determine the parameters of geometric similarity ratio, mechanical similarity ratio, and dynamic similarity ratio;

[0066] 1. Conduct on-site investigations of the actual dimensions and construction of village houses, and consult relevant documents to obtain the physical and mechanical parameters of bricks and the mechanical properties of masonry structures. Among these, the construction details include: structural type and material (brick and wood, brick and stone, brick and concrete, etc.), whether it is a single-story or multi-story building, and whether it has ring beams and structural columns.

[0067] The most important physical quantities for measuring a material's resistance to deformation are its elastic modulus and Poisson's ratio. Based on the types of bricks surveyed on-site (clay bricks, cement bricks, coal gangue bricks, fly ash bricks, etc.), the corresponding elastic modulus and Poisson's ratio were consulted. It is worth noting that for buildings used for a long time, to more accurately reflect their deformation, the structural and material strengths need to be appropriately reduced based on experimental data.

[0068] A field survey and review of relevant data were conducted to obtain the mechanical properties of the village's masonry structures, mainly including the tensile strength, compressive strength, and shear strength. Table 1, showing the mechanical properties of various types of masonry structures, was created to record these properties.

[0069] Table 1 Mechanical Properties of Masonry Structures of Various Types of Buildings

[0070]

[0071] 2. Based on the dimensions and structure of the houses surveyed on-site, and the design requirements of the experimental platform and model, calculate and determine the similarity ratio parameters.

[0072] In house model damage simulation experiments, scaled-down models are usually used. In order to better reveal the loading response and deformation law of the prototype structure, three types of similarity are mainly considered when designing and making the model: geometric similarity, mechanical similarity, and dynamic similarity.

[0073] (1) The geometric similarity ratio used in house model tests requires that the model and the on-site house have similar geometric shapes, and that their dimensions (length, width, height, and thickness) are in a certain proportion. The geometric similarity ratio a can be determined according to the dimensions of the prototype building and the simulation test platform, the specific research objectives, and the accuracy requirements. l .

[0074]

[0075] In the formula: a l The geometric similarity ratio; l M For model dimensions and length; l H The dimensions and length of the houses in the mining area.

[0076] (2) Mechanical similarity means that the physical and mechanical properties of the house prototype and the brick model, as well as the masonry structure, remain similar.

[0077] Mechanical similarity of model bricks: Suitable model test bricks should meet three main similarity conditions: similarity ratio of stress, similarity ratio of elastic modulus, and similarity of Poisson's ratio of model bricks;

[0078] a. Stress in the model brick: The ratio of the stress in the strain curve of the model brick to the stress of the prototype brick is equal to the ratio of its geometric dimensions, i.e., a σ =a l And the strain values ​​are the same, i.e., a ε =ε M / ε H =1;

[0079] Where: a σ The stress ratio between the model bricks and the prototype bricks of the houses in the mining area; a ε ε is the ratio of the strain values ​​of the model bricks to the prototype bricks of the mining area houses. M ε represents the strain value of the model brick; H The strain value of the bricks in the houses in the mining area;

[0080] b. Similar elastic modulus: The elastic modulus of the model bricks and the prototype bricks of the mining area houses are the same or similar, that is...

[0081]

[0082] Where E M E represents the elastic modulus of the model brick. H a is the elastic modulus of the bricks used in the mining area. E The ratio of elastic modulus;

[0083] c. Similarity in Poisson's ratio: The model bricks and the prototype bricks of the mining area houses have the same Poisson's ratio, that is...

[0084]

[0085] μ M Where is the Poisson's ratio of the model bricks; μ H Let a be the Poisson's ratio of the bricks used in the mining area's houses. μ This is the ratio of Poisson's ratio of the model bricks to the house bricks;

[0086] Mechanical similarity of masonry structures: The mechanical similarity of masonry structures includes the similarity of three parameters: tensile strength, compressive strength and shear strength.

[0087] (3) Dynamic similarity means that all forces between the masonry house model and the prototype house remain similar. The dynamic similarity ratio is a. k :

[0088]

[0089] Where, γ M The bulk density of the mixed material in the model is kg / m³. 3 ;γ H The bulk density of the prototype composite material is kg / m³. 3 ;l M For model dimensions and length; l H The dimensions and length of the houses in the mining area.

[0090] II. Based on the experimental theory of similar material models in mining subsidence physics, the experimental materials for simulating houses were determined, and house model bricks with different material ratios were made using molds according to the geometric similarity ratio.

[0091] 1. Based on the geometric similarity ratio obtained in step one, construct a brick mold that conforms to the geometric similarity ratio; in the brick mold, the length, width, and height of each brick unit satisfy l = L × a l l and L represent the dimensions of the model bricks and the dimensions of the bricks used to build houses in the mining area, respectively. l It is the geometric similarity ratio;

[0092] 2. Prepare the experimental materials for the model bricks:

[0093] In model experiments, the selection of model materials is crucial, as different materials will alter the similarity relationship. Based on the theory of similar material model experiments in mining subsidence physics, the model experimental materials are one or more of lime, cement, laterite, and gypsum. The composition and ratio of different experimental materials are selected according to the simulation results to adjust the overall strength of the bricks.

[0094] For example, lime and cement can be used as model test materials. Lime is the basic aggregate and the main raw material for making bricks, while cement is the strength control material. By changing the proportion of the mixed materials, the overall strength of the model bricks can be adjusted.

[0095] Alternatively, depending on the building's condition, a single model material can be selected to prepare the model bricks.

[0096] Experimental materials should generally meet the following conditions:

[0097] ① Some mechanical properties of the material are similar to those of actual bricks used in houses;

[0098] ②The mechanical properties of the material remained relatively stable during the experiment;

[0099] ③ Changing the material ratio can result in a wide range of variations in the mechanical properties of the materials;

[0100] ④ The raw materials are widely available and inexpensive.

[0101] Red clay and gypsum are good choices for making model bricks because they have good mechanical properties and have been frequently used in previous experiments.

[0102] 3. Making model bricks: Mix experimental materials with water in different proportions, and use brick molds to make house model bricks with different material ratios;

[0103] When making model bricks, first, thoroughly mix experimental materials (lime, cement, red clay, and gypsum) in different proportions with water until a paste is formed. Then, pour the paste into a mold, smooth the surface, and ensure there are no air pockets or other impurities. Let it air dry in a ventilated place. After it is completely dry, carefully remove the small bricks one by one to obtain model bricks with different mechanical strengths. Generally, the ratio of lime to cement is between 1:1 and 10:1.

[0104] 3. Conduct mechanical testing experiments on the bricks of the house model, compare the elastic modulus and Poisson's ratio of the house model with the house prototype, calculate the degree of conformity of the mechanical parameters, determine the optimal experimental material ratio, and select the model bricks with the optimal experimental material ratio as the preferred model bricks for the experiment.

[0105] In the theory of mechanical similarity, there are three similarity parameters: the stress-strain curves of the brick model and the prototype brick are similar, that is, the stress values ​​are similar (a). σ =a l The strain values ​​are the same (a) ε =ε M / ε H =1, the ratio of elastic moduli a E =E M / E H =1. The ratio of Poisson's ratio, a μ =μ M / μ H =1.

[0106] Mechanical experiments were conducted on model bricks with different material ratios to obtain their stress-strain curves, elastic modulus, and Poisson's ratio. These results were then compared with the actual physical and mechanical properties of the prototype bricks on-site. The degree of conformity between the mechanical parameters of the model bricks under each material ratio and the prototype bricks was determined, leading to the identification of the optimal experimental material ratio for the model bricks. Bricks with this optimal material ratio were then selected as the preferred model bricks for the experiment.

[0107] The formula for calculating the degree of conformity (k) between the mechanical parameters of the model bricks and the prototype bricks of the house is as follows:

[0108]

[0109] In the formula, k represents the degree of conformity of the mechanical parameters; the smaller the value, the higher the similarity of the mechanical properties between the model bricks and the prototype bricks of the house; E M E represents the elastic modulus of the model brick. H μ is the elastic modulus of the bricks used in mining area houses. M μ is the Poisson's ratio of the model bricks. H ε is the Poisson's ratio of the bricks used in the mining area's houses; M ε represents the strain value of the model brick; H The strain value is the value of the bricks in the houses in the mining area.

[0110] 4. Select the bonding material between the bricks of the house model, make a masonry model of the house model bricks, and conduct mechanical experiments to compare it with the house prototype to determine the optimal bonding material between the bricks of the house model.

[0111] 1. Select the bonding material between the bricks and use the model bricks to make a masonry wall;

[0112] For the selected model bricks, a suitable inter-brick bonding material needs to be chosen to construct the masonry wall. The inter-brick bonding material is essential for the model bricks to bond together and form masonry. Besides possessing its own adhesive properties, this material must also have a certain affinity with the model bricks. Referring to relevant literature and actual construction project conditions, adhesives such as glue, clay, glass glue, alcohol glue, fabric adhesive, and cement can be selected as alternative bonding materials. Cement mortar can also be used.

[0113] 2. Control the thickness of the bonding material;

[0114] In model experiments, it is also necessary to pay attention to the thickness control of the adhesive material between bricks. The adhesive should be kept as thin as possible to minimize the size effect. In actual engineering, the thickness of mortar between building bricks is generally 8-12mm. In model experiments, the thickness of the adhesive should be reasonably controlled according to the similarity ratio taken, generally 1-3mm, to ensure the rationality of the model experiment.

[0115] 3. Conduct mechanical tests on the masonry structure made of cemented bricks in the model, and compare the compressive strength R between the prototype house and the model masonry. 压 Tensile strength R 拉 and shear strength τ 剪 ,

[0116] Tensile strength, compressive strength, and shear strength tests of the model masonry.

[0117] The loading method throughout the test should be carried out in accordance with the current testing standard "Technical Standard for On-site Testing of Masonry Engineering" in order to obtain experimental results under standard experimental conditions.

[0118] Compressive strength test of model masonry. When testing the compressive strength of model masonry, firstly, a horizontal groove equivalent to the size of a flat top is cut at a certain distance in the vertical direction of the wall. A hydraulic flat top is embedded in each groove and fixed with a self-balancing tie rod. Then, a manual oil pump is used to apply graded loading to the masonry between the grooves until the masonry under pressure fails, and the ultimate compressive strength of the masonry is obtained.

[0119] Tensile strength testing of model masonry. Typically, the tensile strength of model masonry is tested using a tensile test method. The sample is placed in a fixture, one end is fixed, and a tensile force is applied to the other end. The tensile force is gradually increased until the sample breaks. The test should be conducted under controlled environmental conditions to ensure the accuracy of the results.

[0120] Shear strength test of model masonry. To test the shear strength of model masonry, a hole is first drilled in the wall in a direction horizontally adjacent to the measuring point. A shearing device is placed inside the hole, a pad is placed behind the shearing device, a manual oil pump is connected to the shearing device, and then a load is manually applied until the masonry breaks. The shear strength of the masonry is then measured.

[0121] 4. If the building on site has ring beams and structural columns, a corresponding model structure should be added to the masonry structure before relevant mechanical tests are conducted;

[0122] If the building on site has structures such as ring beams and structural columns, these structures should be added at the corresponding locations on the building. Ring beams and structural columns mainly increase the tensile and shear strength of the building. During the simulation, depending on the strength of these structures on the building, wire, bamboo sticks, or grass stems should be added to the cement and lime mixture to simulate these structures.

[0123] After the house with ring beams and structural columns is completed, test the tensile, compressive and shear mechanical properties of the model house. The test process is the same as step 3 in step four.

[0124] 5. Based on the actual condition of the house, construct a house model according to the overall geometric similarity ratio and dynamic similarity ratio.

[0125] 1. Based on the house prototype, the optimal masonry bonding material, and the geometrically similar scale, the model house dimensions are calculated. The model bricks are then stacked to create a preliminary village house model.

[0126] 2. Based on the principle of dynamic similarity, determine whether the model house needs counterweight.

[0127] In masonry structures, the vertical compressive stress caused by gravity loads has a certain impact on the structural stiffness and strength. Therefore, in order to ensure that a small-scale model can accurately reproduce the deformation characteristics of the prototype, the principle of dynamic similarity must be satisfied between the model and the prototype during model experiments.

[0128] Based on the principle of dynamic similarity, it is determined whether counterweight is needed to make the house model, and the house model is finally made.

[0129] If m M =m H a k Then no counterweight is needed;

[0130] If m M ≠m H a k Therefore, counterweights are needed; the counterweights are evenly applied to the roof or eaves, and the mass of the counterweights is Δ = m. H a k -m M ;

[0131] In the formula, a k For the dynamic similarity ratio, m H The total weight of the prototype house is m. M This refers to the overall weight of the model house.

[0132] In this application, a brick-concrete structure house in Fengfeng Mining District, Handan City, Hebei Province is used as an example for the following explanation.

[0133] (1) The study area is located in Fengfeng Mining District, Handan City, Hebei Province. The village has more than 800 households. Most of the houses in the village are single-story brick-concrete structures without ring beams or structural columns. Each household has an independent courtyard with 3 to 5 rooms. The size of a single room is about 5.0*3.0m and the floor height is about 3.5m.

[0134] Based on the survey data of the houses on site and the model design requirements, the geometric similarity ratio 'a' was calculated and determined. l The ratio is 1:30; in mechanical similarity: stress ratio a σ =a l Time strain ratio a ε =1, elastic modulus ratio a E =1, the ratio of Poisson's ratio a μ =1;

[0135] Dynamic similarity ratio ak It is the product of the geometric similarity ratio and the bulk density ratio, and is related to the bulk density of the experimental material used.

[0136] The density ratio of gypsum bricks to that of red clay bricks (in mining areas) is about 1:2, while the density ratio of cement bricks to red clay bricks is about 1:1.

[0137] When selecting gypsum: kinetic similarity ratio a k The ratio is 1:60.

[0138] When using red clay or cement: kinetic similarity ratio a k The ratio is 1:30.

[0139] (2) The experiment used three raw materials—red clay, cement, and gypsum powder—to make bricks for the masonry house model. The adhesives used were alcohol glue, glass glue, and cement. The brick and house making process was as follows: The experimental raw materials were mixed with water and poured into a mold to make bricks (brick size 50mm*30mm*20mm). The bricks were then bonded together according to the geometric similarity ratio to form a masonry wall. The need to add counterweight was determined according to the dynamic similarity ratio to complete the masonry house model.

[0140] (3) Conduct mechanical testing experiments on brick and masonry models, and calculate the degree of conformity between the mechanical parameters of the comparative model and the prototype.

[0141] Table 1

[0142]

[0143] As shown in Table 1, red clay model bricks can be combined with glass glue, plaster model bricks with alcohol glue, and cement bricks with cement to form masonry models. However, other model bricks are incompatible with the adhesives and are difficult to form masonry structures.

[0144] Then, mechanical strength tests were conducted on the masonry structures made of three experimental materials: red clay model bricks with glass glue, plaster model bricks with alcohol glue, and cement bricks with cement.

[0145] pass Figure 3 The mechanical tests shown in the experiment indicate that the mechanical strength of cement bricks combined with cement is too high, while the mechanical strength of red clay model bricks combined with glass glue is too low. The mechanical structure of these two masonry structures does not meet the requirements.

[0146] Only the combination of gypsum bricks and alcohol-based adhesive can achieve the minimum mechanical parameter compliance k. Therefore, the experimental materials of gypsum and adhesive were chosen to be a combination of gypsum and alcohol-based adhesive.

[0147] Furthermore, the optimal simulation materials and manufacturing process for village house models were determined using a 7:1 mixture of gypsum powder and water as aggregate and alcohol glue as binder.

[0148] (4) The development of cracks in the building is observed when the model is subjected to surface tensile deformation. Figure 4 As shown.

[0149] Depend on Figure 4 It can be seen that, Figure 4 The figure 'a' represents the simulation results from numerical simulation software. From left to right, the amount of ground movement and deformation increases. The areas most vulnerable, with increased deformation, are the four corners of doors or windows, the junctions of roofs and walls, and the junctions of walls and the ground. This is consistent with... Figure 4 The simulation effect of the model experimental platform in section b is similar. From left to right, the gaps at the junction of the roof and walls, and at the junction of the walls and the ground, gradually increase, and then all four corners connecting the windows crack. This is consistent with the actual crack distribution on the right side of the site, which all start from the four corners of the windows and connect to the roof and the floor.

[0150] Compared to conventional numerical simulation experiments, this model experiment can not only reflect the location and form of cracks in mining-affected buildings, but also intuitively show the size of cracks and their development process, and has a higher degree of consistency with the actual situation.

[0151] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A process for fabricating an experimental model of village houses based on similarity theory, characterized in that, The steps include the following: (1) Based on the actual size, structure and building materials of village houses in the mining area, and the design requirements of the experimental platform and model, determine the parameters of geometric similarity ratio, mechanical similarity ratio and dynamic similarity ratio; (2) Based on the experimental theory of similar material models in mining subsidence science, determine the experimental materials for simulating houses, and make house model bricks with different material ratios using molds according to the geometric similarity ratio; (3) Conduct mechanical testing experiments on the house model bricks, compare the elastic modulus and Poisson's ratio mechanical parameters of the house model and the house prototype, calculate the mechanical parameter conformity, determine the optimal experimental material ratio, and select the house model bricks with the optimal experimental material ratio as the preferred experimental model bricks. In step (3), mechanical experiments are conducted on model bricks with different experimental material ratios to obtain the stress-strain curves, elastic modulus and Poisson's ratio of the model bricks; and the actual physical and mechanical properties of the prototype bricks are compared to determine the degree of conformity between the mechanical parameters of the model bricks and the prototype bricks under each experimental material ratio condition, the optimal experimental material ratio for making model bricks is determined, and the model bricks made with the optimal experimental material ratio are selected as the preferred experimental model bricks. The degree of conformity of the mechanical parameters between the model brick and the prototype brick k The calculation formula is: ； In the formula, k The smaller the value of the mechanical parameter conformity, the higher the similarity of the mechanical properties between the model brick and the prototype brick. E M The elastic modulus of the model brick; E H The elastic modulus of the prototype brick. μ M The Poisson's ratio of the model bricks; μ H Poisson's ratio of the prototype brick; ε M The strain value of the model brick; ε H The strain value is that of the prototype brick. (4) Select the bonding material between the bricks of the house model, make a masonry model of the house model bricks, and conduct mechanical experiments to compare it with the house prototype to determine the optimal bonding material between the bricks of the house model. (5) Based on the actual situation of the house, make a house model according to the overall geometric similarity ratio and dynamic similarity ratio of the house.

2. The process for fabricating a village house experimental model based on similarity theory according to claim 1, characterized in that, In step (1), the actual size and structure of the village houses were investigated on-site, and the physical and mechanical parameters of the bricks and the mechanical properties of the masonry structure were obtained by consulting relevant materials; The actual dimensions and construction details of village houses include: structural type and materials, whether they are single-story or multi-story buildings, and whether they have ring beams and structural columns; Physical and mechanical parameters of bricks: elastic modulus and Poisson's ratio; based on the types of bricks surveyed on site, consult the corresponding elastic modulus and Poisson's ratio of the bricks. Mechanical properties of masonry structures: tensile strength, compressive strength, and shear strength of the structure; based on on-site investigation and review of relevant data, the mechanical properties of village house masonry structures were obtained.

3. The process for fabricating a village house experimental model based on similarity theory according to claim 1, characterized in that, In step (1), based on the size and structure of the houses surveyed on site, and the design requirements of the experimental platform and model, the similarity ratio parameters are calculated and determined, including the geometric similarity ratio, mechanical similarity ratio, and dynamic similarity ratio. Geometric similarity requires that the model and the on-site building have similar geometry, with length, width, height, and thickness all maintaining a certain proportion. The geometric similarity ratio is determined based on the dimensions of the prototype building and the simulation test bench, the specific research objectives, and the accuracy requirements. a l ; （1）； In the formula: a l It is the geometric similarity ratio; l M The model's length; l H The length is the prototype size.

4. The process for fabricating a village house experimental model based on similarity theory according to claim 3, characterized in that, Dynamic similarity: All forces between the house model and the house prototype remain similar; dynamic similarity ratio a k : ； in, The bulk density of the mixed material in the model is kg / m³. 3 ; The bulk density of the prototype composite material is kg / m³. 3 ; l M The model's length; l H The length is the prototype size.

5. The process for fabricating a village house experimental model based on similarity theory according to claim 1, characterized in that, Step (2) includes the following: (2-1) Based on the geometric similarity ratio obtained in step (1), a brick mold that conforms to the geometric similarity ratio is made; in the brick mold, the length, width, and height of each brick unit satisfy the following conditions. , l , L These are the dimensions of the model brick and the dimensions of the prototype brick, respectively. a l It is the geometric similarity ratio; (2-2) Preparation of experimental materials for model bricks: The experimental materials for the model are one or more of lime, cement, red clay and gypsum. The composition and ratio of different experimental materials are selected according to the simulation to adjust the overall strength of the model bricks. (2-3) Making model bricks: Mix experimental materials with water in different proportions, and use brick molds to make house model bricks with different material ratios; the specific method of making model bricks is as follows: First, mix the selected model experimental materials with water thoroughly and stir until it becomes a paste, then pour it into the mold, smooth the surface of the mold and ensure that there are no air holes or other impurities in the middle, and let it air dry in a ventilated place; after it is completely dry, carefully take out the small bricks one by one to obtain model bricks with different mechanical strengths.

6. The process for fabricating a village house experimental model based on similarity theory according to claim 1, characterized in that, Step (4) includes the following steps: (4-1) Select the bonding material between the bricks of the house model and make masonry walls from the bricks; the bonding material between the bricks of the house model is one or more of the following: paste, clay, glass glue, alcohol glue, fabric glue and cement; (4-2) Control the thickness of the adhesive material between the bricks of the house model; the thickness of the adhesive material between the bricks of the house model is 1-3 mm; (4-3) Conduct mechanical tests on the masonry structure of the model bricks bonded together, and compare the compressive strength between the masonry of the house prototype and the house model. R 压 ,tensile strength R 拉 and shear strength τ 剪 Determine the optimal bonding material between the bricks of the house model; conduct mechanical tests. (4-4) If the on-site house has ring beams and structural columns, add the corresponding model structure to the masonry structure and then conduct relevant mechanical tests; during the simulation, according to the strength of the on-site house structure, add iron wire, bamboo sticks or grass stems to the cement and lime mixture to simulate the ring beams and structural columns.

7. The process for fabricating a village house experimental model based on similarity theory according to claim 4, characterized in that, Step (5) includes the following steps: (5-1) Based on the house prototype, the optimal bonding material between the house model bricks, and the dimensions of the house model calculated according to the geometric similarity ratio, the model bricks are stacked to initially create the house model. (5-2) Based on the principle of dynamic similarity, determine whether the house model needs counterweight.

8. The process for fabricating a village house experimental model based on similarity theory according to claim 7, characterized in that, Based on the principle of dynamic similarity, determine whether the house model needs counterweight, and finally complete the house model construction: like m M = m H a k Then no counterweight is needed; like m M ≠ m H a k Therefore, counterweights are required; the counterweights should be evenly applied to the roof or eaves, and the mass of the counterweights should be [missing information]. ; In the formula, a k For dynamic similarity ratio, m H This refers to the overall weight of the prototype house. m M This refers to the overall weight of the house model.

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