CN110398400B - 3D printing reconstruction method of fractured structure rock mass and fractured structure rock mass - Google Patents

3D printing reconstruction method of fractured structure rock mass and fractured structure rock mass Download PDF

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CN110398400B
CN110398400B CN201910592802.9A CN201910592802A CN110398400B CN 110398400 B CN110398400 B CN 110398400B CN 201910592802 A CN201910592802 A CN 201910592802A CN 110398400 B CN110398400 B CN 110398400B
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rock mass
fractured
printing
rock
natural
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CN110398400A (en
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夏英杰
张传庆
单治钢
周辉
高阳
刘宁
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Wuhan Institute of Rock and Soil Mechanics of CAS
PowerChina Huadong Engineering Corp Ltd
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Wuhan Institute of Rock and Soil Mechanics of CAS
PowerChina Huadong Engineering Corp Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B33Y10/00—Processes of additive manufacturing
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    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00—Data acquisition or data processing for additive manufacturing
    • B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
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    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
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    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
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    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
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    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
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Abstract

The invention relates to a 3D printing reconstruction method of a fracture structure rock mass and the fracture structure rock mass, which mainly comprises the following steps: determining the mechanical property and the destructive property of rock blocks in the rock mass with the natural fracture structure; determining the shearing and stretching mechanical properties and the destruction characteristics of a structural plane in the natural fractured rock mass; determining the mechanical property similarity ratio of the rock mass and the structural surface of the 3D-printed reconstructed fractured structure rock; selecting a rock 3D printing material and ensuring similarity; selecting a 3D printing material and designing a structure; and 3D modeling and outputting of the fractured rock mass. The 3D printing reconstruction method can accurately reconstruct the fractured structure rock mass with a complex structure, and on the basis, destructive tests of the fractured structure rock mass with completely consistent structures under different mechanical boundary conditions can be carried out.

Description

3D printing reconstruction method of fractured structure rock mass and fractured structure rock mass
Technical Field
The invention relates to the technical field of geotechnical engineering, in particular to a 3D printing reconstruction method of a fracture structure rock mass and the fracture structure rock mass.
Background
For rock engineering, engineering design and corresponding safety measures need to be made according to the mechanical properties of fractured rock masses. The fractured rock mass is composed of rock blocks and structural planes, and is relatively complex. Therefore, the reconstruction of the fractured rock mass has important influence on engineering design and safety and stability evaluation.
However, for the current mechanical test of the fractured structure rock mass, the fracture of the fractured structure rock mass sample in the test enables the test to have one-time characteristics, so that the mechanical characteristics of the fractured structure rock mass with completely consistent structures under different mechanical boundary conditions cannot be obtained in the mechanical test, and the mechanical characteristics of the fractured structure rock mass and the related change rules thereof are inaccurate.
Disclosure of Invention
The invention provides a 3D printing reconstruction method of a fractured structure rock mass and the fractured structure rock mass, solves the technical problem that the mechanical properties of the fractured structure rock mass with completely consistent structures under different mechanical boundary conditions cannot be obtained in the existing mechanical test, realizes the mechanical test of the expandable fractured structure rock mass with completely consistent structures under different stress levels, finally obtains the mechanical and destructive characteristics of the rock mass with the same fractured structure, and provides a guidance technical effect for the related design of rock mass engineering.
The invention provides a 3D printing reconstruction method of a fracture structure rock mass and the fracture structure rock mass, which comprises the following steps:
carrying out uniaxial compression mechanical test on the rock mass in the natural fracture structure rock mass to obtain the stress-strain mechanical property and the failure property of the rock mass;
carrying out shearing and tensile tests on a structural surface in a natural fractured structure rock mass to obtain the structural surface shearing and tensile mechanical properties and destruction characteristics of the fractured structure rock mass;
determining the mechanical property similarity ratio of the rock mass and the structural surface of the 3D-printed reconstructed fractured structure rock;
selecting a rock 3D printing material and ensuring similarity;
selecting a 3D printing material and designing a structure;
and 3D modeling and outputting of the fractured rock mass.
Preferably, the uniaxial compression mechanical test of the rock mass in the natural fractured rock mass comprises the following steps: carrying out uniaxial compression test of the wall rock mass, wherein:
the shape of the test rock block core can be selected to be a cylinder, the diameter of the test rock block core is 50mm, and the height of the test rock block core is 100 mm;
and (4) drawing a stress-strain curve of the rock mechanical test, and analyzing the damage characteristics of the rock core of the rock.
Preferably, the shear and tensile test of the structural plane in the natural fractured structural rock mass comprises the following steps:
carrying out a shearing test on the structural plane of the natural fractured structure rock mass, and determining the shearing mechanical property and the destruction characteristic of the structural plane of the fractured structure rock mass;
and carrying out a tensile test on the structural surface of the natural fractured structure rock mass, and determining the tensile mechanical property and the failure characteristic of the structural surface of the fractured structure rock mass.
Preferably, the determining of the mechanical property similarity ratio of the rock mass and the structural surface in the fractured rock mass comprises the following steps:
carrying out an on-site bearing plate test and a true triaxial test on the natural fractured structure rock mass, and determining the strength, the elastic modulus and the deformation of the natural fractured structure rock mass;
measuring the density of the natural fracture structure rock mass;
determining the similarity ratio of the physical and mechanical properties of the 3D printed reconstructed fractured structure rock mass and the natural fractured structure rock mass according to a similarity ratio formula, wherein the similarity ratio formula is as follows:
Figure BDA0002116604370000021
in the formula, CiIs the similarity ratio of the corresponding physical mechanical properties of i, wherein i is the category of the physical mechanical properties, and comprises: stress (σ), elastic modulus (E), density (γ), sample side length (L), Poisson's ratio (upsilon) and strain (ε), the iRSThe i is the category of the physical mechanical properties of the reconstructed fractured structure rock massCJBsIs the category of the physical and mechanical properties of the natural fractured rock mass,
Cσ＝CE(2)，
Cε＝Cυ＝1 (3)，
Cσ＝Cγ·CL(4)。
preferably, the rock mass 3D printing material comprises: photosensitive resin, gypsum, ceramics, epoxy resin, and the like.
Preferably, after the 3D rock block printing material is determined, similarity verification is carried out on the mechanical and destructive characteristics of the 3D rock block printing material through a uniaxial compression test, so that the brittle failure characteristics and the mechanical characteristics of the 3D printing reconstructed fractured structure rock mass and the natural fractured structure rock mass are similar.
Preferably, the selection of the structural surface 3D printing material and the structural design include:
the structural surface of the 3D printing reconstructed fractured structure rock mass is designed by adopting a net structure;
three-dimensional point cloud data are obtained by three-dimensionally scanning the wall surface fluctuation degree of the rock mass with the natural fracture structure;
completing structural surface wall surface structure printing of the 3D printing reconstructed fracture structure rock mass according to the mesh structure design and the three-dimensional point cloud data;
and carrying out shearing and tensile tests on the structural plane of the 3D printing reconstructed fractured structure rock mass, and verifying the effectiveness of the 3D printing reconstructed fractured structure rock mass network structure design through similarity comparison of test results.
Preferably, the structural surface of the 3D-printed fractured rock mass adopts a net structure design, and the specific method comprises the following steps:
if the reconstitution size is
Figure BDA0002116604370000031
The cross-sectional area of the cylinder is:
Figure BDA0002116604370000041
in the formula: stotalIs the cross-sectional area in mm2；DtotalIs the cross section diameter in mm;
if Fullcure 720 (photosensitive resin) is adopted as the material of the reconstruction structure surface (tensile strength is 40MPa) in the 3D printing reconstruction process, the tensile strength ratio R of the net structure and the Fullcure 720 on the whole section isnetComprises the following steps:
Figure BDA0002116604370000042
the total area S of the net structure of the rock mass structural planenetComprises the following steps:
Snet＝Rnet·Stotal＝0.002×1962.5＝3.93mm2(7)
if the diameter D of the connecting point of the net structure is setpoint0.2mm, the area S of each connection pointpointComprises the following steps:
Figure BDA0002116604370000043
the number N of web connection points required in the cross-sectionpointComprises the following steps:
Figure BDA0002116604370000044
if the mesh structure connection point is squareArranged in a pattern such that the spacing between the connection points is LpointCan be calculated as:
Figure BDA0002116604370000045
in the aspects of 3D printing reconstruction fracture structure rock mass structural surface shearing mechanics and destruction characteristics, 3D scanning is required to be carried out on a natural rock mass structural surface, and 3D point cloud data of the wall surface fluctuation degree of the reconstruction fracture structure rock mass structural surface are obtained;
and reconstructing the rock mass structural plane on the basis of the selection of the rock mass material on the wall surface of the structural plane and the 3D scanning point cloud data by adopting a 3D printing technology.
Based on the same inventive concept, the application also provides a fractured structure rock mass which is prepared by the 3D printing reconstruction method of the fractured structure rock mass.
The 3D printing reconstruction method of the fractured structure rock mass and the fractured structure rock mass provided by the application at least have the following technical effects or advantages:
the application provides a 3D printing reconstruction method of a fracture structure rock mass and the fracture structure rock mass, which can accurately reconstruct a complex fracture structure rock mass, and realize accurate reconstruction of the geometry and mechanics of the complex fracture structure rock mass by adopting a 3D printing method after accurately measuring the rock mass strength and the shearing and tensile mechanical properties of a structural surface of the complex fracture structure rock mass through physical tests. In the reconstruction process, through mechanical test tests, 3D printing related materials of the rock mass with the reconfigurable complex fracture structure are selected, and the finally generated fracture structure rock mass is consistent with the rock mass with the natural fracture structure. Therefore, on the basis, destructive tests of fractured structure rock masses with completely consistent structures under different mechanical boundary conditions can be carried out, the one-time problem of the natural fractured structure rock mass destructive tests is solved, the cognition of the mechanics and destructive characteristics of the complex fractured structure rock mass can be improved, and references are provided for related engineering design and stability evaluation of the fractured structure rock mass. Therefore, the technical problem that the mechanical properties of the fractured structure rock mass with completely consistent structures under different mechanical boundary conditions cannot be obtained in a mechanical test in the prior art is effectively solved, the mechanical test of the fractured structure rock mass with completely consistent structures under different stress levels can be developed, the mechanical and destructive properties of the same fractured structure rock mass can be finally obtained, and the technical effect of guidance is provided for the related design of rock engineering.
Drawings
Fig. 1 is a schematic flow chart of a 3D printing reconstruction method for a fractured rock mass according to an embodiment of the present invention;
FIG. 2 is a shear stress-shear displacement curve diagram of a rock mass structural plane with a natural fracture structure provided by an embodiment of the invention;
FIG. 3 is a tensile stress-strain curve of a structural plane of a rock body with a natural fracture structure according to an embodiment of the present invention;
FIG. 4 is a diagram of internal structural defects of a rock mass structural plane of a natural fracture structure according to an embodiment of the present invention;
FIG. 5 is a graph of the stress-strain relationship of a 3D printed material for reconstructing a rock mass structure provided by an embodiment of the invention;
fig. 6 is a schematic diagram of a network structure of a reconstructed fracture structure rock mass structural plane provided by an embodiment of the invention.
Detailed Description
The embodiment of the application provides a 3D printing reconstruction method of a fractured structure rock mass and the fractured structure rock mass, solves or partially solves the technical problem that the mechanical properties of the fractured structure rock mass with completely consistent structures under different mechanical boundary conditions cannot be obtained in the existing mechanical test, realizes the mechanical test of the fractured structure rock mass with completely consistent structures under different stress levels, finally obtains the mechanical and destructive properties of the same fractured structure rock mass, and provides a guiding technical effect for the related design of rock engineering.
In order to achieve the purpose, the technical scheme adopted by the application is as follows:
1. determining the mechanical and destructive characteristics of rock masses in natural fractured rock masses, comprising:
obtaining the standard size of the rock mass with a natural fracture structure
Figure BDA0002116604370000061
Obtaining uniaxial compressive strength and strain corresponding to the uniaxial compressive stress-strain curve of the rock sample;
summary of Standard dimensions
Figure BDA0002116604370000062
Failure characteristics of rock specimens.
2. Determining the shearing, stretching and destroying characteristics of the structural plane in the natural fracture structure rock mass, which comprises the following steps:
acquiring the shearing mechanical characteristics of a structural plane of a natural fracture structure rock mass with standard size (100mm multiplied by 100mm) under the normal stress condition, wherein the shearing mechanical characteristics comprise a shearing stress-shearing displacement curve;
optionally, the normal stress of the shear test may be set to 5 MPa;
summarizing the failure characteristics of the shear test;
obtaining standard size
Figure BDA0002116604370000063
Obtaining uniaxial tensile strength and strain corresponding to the uniaxial tensile stress-strain curve of a structural surface in the natural fractured rock mass;
and summarizing the tensile failure characteristics of the rock mass structural plane with the natural fracture structure.
3. Determining the mechanical property similarity ratio of the rock mass and the structural surface of the 3D printed reconstructed fractured structure:
because the indoor mechanical test needs to be carried out after the reconstruction of the fractured structure rock mass sample, the size of the fractured structure rock mass sample needs to meet the relevant requirements of the indoor test, and therefore the physical mechanical property similarity ratio of the rock mass and the structural surface of the accurately reconstructed fractured structure rock mass needs to be determined, and the method mainly comprises the following steps: strength, modulus of elasticity, density, side length dimension, poisson's ratio, strain, and the like.
4. Rock 3D printing material selection and similarity guarantee:
the 3D printing materials which can be used for reconstructing the fractured rock mass and rock mass structure at present mainly comprise photosensitive resin, gypsum, ceramic, epoxy resin and the like, and the related materials most suitable for reconstructing the rock mass structure are selected according to the physical and mechanical properties of the related materials.
In the material selection process, mechanical tests of different materials can be carried out, the physical and mechanical properties of related materials are obtained, and whether the similarity requirements are met or not is judged.
5. Selecting a 3D printing material and designing a structure:
according to the tensile and shear mechanics characteristics of the fracture structure rock mass structural plane, preliminarily selecting a 3D printing material applicable to a reconstructed structural plane, wherein the printing material needs to meet high brittleness characteristics:
(1) in terms of tensile mechanics and failure characteristics:
selecting a 3D printing material suitable for a reconstructed structural surface according to a tensile test result and a damage characteristic of a structural surface of a rock body with a natural fracture structure;
optionally, if the tensile strength of the 3D printing reconstructed structural surface is not consistent with that of the natural fracture structure rock structural surface, the 3D printing reconstructed structural surface can be designed by adopting a net structure to meet the tensile strength requirement.
(2) In terms of shear mechanics and failure characteristics:
3D scanning is carried out on the rock structural plane of the natural fracture structure, and 3D point cloud data of the fluctuation degree of the wall surface of the reconstructed rock are obtained;
and reconstructing a structural surface wall structure on the basis of wall rock block material selection and 3D scanning point cloud data by adopting a 3D printing technology.
6. 3D modeling and outputting of a fractured rock mass:
on the basis of structural surface design and material selection, corresponding 3D printing equipment is selected, and then the method is adopted to model and output structures such as rock blocks, structural surfaces and the like of the rock mass sample with the complex fracture structure.
According to the content, in the 3D printing reconstruction process of the rock sample with the complex fracture structure, after the rock strength, the wall surface fluctuation degree, the shearing and stretching mechanical properties of the rock sample with the complex fracture structure are accurately measured through physical tests, the 3D printing method is adopted, and the accurate geometrical and mechanical reconstruction of the rock sample with the complex fracture structure is realized. In the reconstruction process, through mechanical test, 3D printing related materials of the rock mass with the reconfigurable complex fracture structure are selected, and finally the generated fracture structure rock mass is consistent with the natural rock mass structure. On the basis, destructive tests of fractured structure rock masses with completely consistent structures under different mechanical boundary conditions can be carried out, the one-time problem of the destructive tests of the natural fractured structure rock masses is solved, the cognition of the mechanics and destructive characteristics of the complex fractured structure rock masses can be improved, and references are provided for related design and stability evaluation of rock mass engineering.
The 3D printing reconstruction method of a fractured rock mass according to the present application will be described in detail by the following embodiments,
referring to the attached drawing 1, the 3D printing reconstruction method for the fractured rock mass provided by the embodiment includes the following steps:
step 101, determining mechanical properties and destructive properties of rock masses in the natural fracture structure rock mass.
In order to obtain the physical mechanics and destructive characteristics of the rock mass of the natural fractured structure rock mass, uniaxial compression mechanical tests need to be carried out on the rock core with the standard size of the rock mass.
In particular, the core may be shaped as a cylinder with a diameter of 50mm and a height of 100 mm.
Moreover, in order to solve the problem of discreteness of the mechanical test result of the rock core, a certain number of rock cores can be tested, and then the average value of the mechanical characteristics and related parameters of the rock cores is calculated and used as the basis for reconstructing the rock mass structure in the fractured rock mass through 3D printing.
Alternatively, the number of the cylindrical cores of the rock mass may be selected to be 5.
After the uniaxial compression test of the core is completed, test results need to be summarized, namely a stress-strain curve of a mechanical test is drawn, and the damage characteristics of the core are analyzed.
Specifically, in this example, the stress-strain relationship curve is plotted with the stress in the test result as the vertical axis and the strain as the horizontal axis, and the average uniaxial compressive strength of the core is 149.6 MPa;
the failure mode of the core was then analyzed, and in this example, the failure mode of each core was brittle failure.
And 102, determining the shearing and stretching mechanical properties and the destruction characteristics of the structural plane in the natural fracture structural rock mass.
In order to determine the shearing and tensile mechanical properties and the failure characteristics of the structural plane in the natural fracture structure rock mass, firstly, a direct shearing test is carried out on the rock mass structural plane;
specifically, in the process of developing a direct shear test, the standard size of the structural surface can be selected to be 100mm × 100mm × 100 mm;
optionally, the normal stress of the shear test can be set to 5MPa, and finally a shear stress-shear displacement curve of the natural fracture structure rock mass structural plane shown in fig. 2 is obtained;
then, acquiring the shear stress under a set normal stress condition from the shear stress-shear displacement curve of the structural surface, and using the shear stress-shear displacement curve as a mechanical basis of the structural surface of the 3D printing reconstructed fractured structure rock mass;
and then, according to the shearing test result of the structural plane, summarizing the damage characteristics of the structural plane of the natural fracture structure rock body under the direct shearing condition.
After the shear mechanics characteristics and the failure characteristics of the rock mass structural plane are obtained, the tensile mechanics and the failure characteristics of the rock mass structural plane need to be determined.
In order to obtain the tensile mechanics and the destructive characteristics of the structural surface of the rock body with the natural fracture structure, the structural surface can be subjected to a direct tensile test.
Optionally, when the structural surface is subjected to a tensile test, the tensile test can be performed in a mode of changing from tensile to compressive;
then, drawing a tensile stress-strain curve of the structural surface to obtain the tensile strength characteristic of the structural surface as shown in fig. 3;
and then, according to the structural surface tensile test result, summarizing the failure characteristics of the structural surface of the natural fracture structure rock mass under the direct tensile condition.
And 103, determining the mechanical property similarity ratio of the 3D printed reconstructed fracture structure rock mass and the structural surface.
Firstly, carrying out an on-site bearing plate test and a true triaxial test of a natural fractured structure rock mass to obtain the mechanical properties of the natural fractured structure rock mass such as strength, elasticity/deformation modulus, deformation and the like, and simultaneously measuring the physical properties of a rock mass sample such as density and the like;
optionally, the diameter of the on-site bearing plate is 50.5cm, and the sample size of the fracture structure rock body true triaxial test is 50cm × 50cm × 100 cm;
on the basis of determining the size of the fractured rock mass sample, further determining the density of the sample, and performing density measurement on the sample by adopting a mass volume method;
then, determining the similarity ratio of the physical and mechanical properties of the corresponding structure of the rock structural plane with the accurately reconstructed fracture structure, wherein the method comprises the following steps:
Figure BDA0002116604370000101
in the formula, CiI is a similarity ratio of the corresponding physical and mechanical properties, i is a category of the physical and mechanical properties, and i includes: stress (. sigma.), modulus of elasticity (E), density (. gamma.), side length (L) of the specimen, Poisson's ratio (. nu.) and strain (. epsilon.), iRSIs the category of the physical mechanical properties of the reconstructed fractured rock mass iCJBsThe method is the category of the physical and mechanical properties of the natural structure rock mass sample.
According to the similarity principle, the similarity ratio of the physical and mechanical properties of the related structure of the fractured rock mass needs to meet the following requirements:
Cσ＝CE(2)
Cε＝Cυ＝1 (3)
further, the similarity relationship between stress and specimen edge length should satisfy:
Cσ＝Cγ·CL(4)
optionally, if the densities of the 3D-printed reconstructed fractured structure rock mass and the natural fractured structure rock mass are close to or consistent with each other, that is: cγWhen 1, then:
Cσ＝CL(5)
the similarity relation between the reconstructed fractured structure rock mass suitable for 3D printing and the site in-situ test is given by a formula 5.
In this embodiment, the diameter size of the in-situ test bearing plate on site is 50.5cm, and if the side length of the 3D-printed reconstructed fractured structure rock mass satisfying the indoor mechanical test is 10cm, the corresponding size similarity ratio is as follows: cL＝50.5/10≈5；
Meanwhile, in order to ensure the accurate reconstruction of the crack structure rock mass, the mechanical properties of the components of each structure of the rock mass, such as rock blocks, structural planes and the like, also meet the similarity ratio.
And 104, selecting a 3D printing material of the rock block and ensuring the similarity.
As mentioned above, the 3D printing materials that can be used to simulate the rock structure at present mainly include photosensitive resin, gypsum, ceramic, epoxy resin, etc., and it is necessary to select the relevant materials that are most suitable for reconstructing the rock structure according to the physical and mechanical properties of the relevant materials.
In the embodiment, through comparison of mechanical and destructive characteristics of various materials, a photosensitive resin material is selected as a 3D printing material for reconstructing a rock structure;
further, performing similarity verification on the 3D printing material of the rock block;
optionally, the core size of the rock mass used for verification may be selected as
Figure BDA0002116604370000111
Further, the verification test is a uniaxial compression test;
further, considering the defectiveness of the internal structure of the natural rock block (as shown in fig. 4), a corresponding defect structure can be added inside the 3D printing sample so as to satisfy the brittle failure characteristics and the mechanical similarity relationship;
in this embodiment, the stress-strain relationship curve of the obtained 3D rock mass printing material is shown in fig. 5, and the mechanical properties and failure modes thereof satisfy the requirements related to similarity.
And 105, selecting a structural surface 3D printing material and designing a structure.
Specifically, according to the tensile test result and the damage characteristic of the rock mass structural plane with the natural fracture structure, selecting a 3D printing material suitable for reconstructing the rock mass structural plane;
further, the selection of the 3D printing material of the structural surface is in accordance with the main characteristics of low strength and high brittleness;
optionally, if the tensile strength of the 3D printed reconstructed rock mass structural plane and the tensile strength of the natural rock mass structural plane do not satisfy the similarity relationship, the 3D printed reconstructed structural plane may be designed to have a mesh structure to satisfy the tensile strength requirement thereof, as shown in fig. 6.
Specifically, in this embodiment, the design process of the mesh structure is as follows:
if the reconstitution size is
Figure BDA0002116604370000121
The cross-sectional area of the cylinder is:
Figure BDA0002116604370000122
in the formula: stotalIs the cross-sectional area in mm2；DtotalIs the cross section diameter in mm;
if in the 3D printing reconstruction process, Fullcure 720 (photosensitive resin) is adopted as the 3D printing material (tensile strength is 40MPa) of the reconstruction structural surface, the tensile strength ratio R of the net-shaped structure and the Fullcure 720 on the whole section isnetComprises the following steps:
Figure BDA0002116604370000123
the total area S of the net structure of the rock mass structural planenetIs composed of
Snet＝Rnet·Stotal＝0.002×1962.5＝3.93mm2(8)
If the diameter D of the web-like structure connecting points is set in fig. 6point0.2mm, the area S of each connection pointpointComprises the following steps:
Figure BDA0002116604370000124
the number N of web connection points required in the cross-sectionpointComprises the following steps:
Figure BDA0002116604370000125
if the network connection points are arranged in a square, the spacing L between the connection pointspointCan be calculated as:
Figure BDA0002116604370000126
further, in the aspects of 3D printing of shear mechanics and destruction characteristics of the reconstructed fractured structure rock mass, 3D scanning needs to be carried out on a structural surface of the natural fractured structure rock mass, and 3D point cloud data of the fluctuation degree of the wall surface of the reconstructed fractured structure rock mass are obtained;
and then, reconstructing a rock mass structure surface by adopting a 3D printing technology on the basis of selecting a rock mass material of the fracture structure rock mass and the 3D scanning point cloud data.
And 106, 3D modeling and outputting of the fractured rock mass.
Specifically, on the basis of related structure design and material selection of the fractured structure rock mass, corresponding 3D printing equipment is determined, and then the fractured structure rock mass is modeled and output according to the method.
According to the embodiment, the 3D printing reconstruction method for accurately reconstructing the rock mass with the complex fracture structure and the rock mass with the fracture structure provided by the application determine the mechanical characteristics of the structural plane of the complex rock mass on the basis of the shearing and tensile test of the structural plane of the natural rock mass and the mechanical test of the rock mass; and then, respectively selecting 3D printing materials of the corresponding structure of the reconstructed fractured structure rock mass by calculating the similarity ratio of the physical and mechanical properties of the corresponding structure of the 3D printed reconstructed fractured structure rock mass, and simultaneously adopting a net structure design and accurate reconstruction and output on a rock mass structural plane. According to the method, the accurate reconstruction of the rock mass with the complex fracture structure can be realized by adopting a 3D printing technology, a plurality of fracture structure rock masses with completely consistent structures can be generated, further, destructive tests of the fracture structure rock masses with completely consistent structures under different mechanical boundary conditions can be carried out, the one-off problem of the conventional rock mass mechanical test damage is solved, and the mechanical characteristics of the fracture structure rock masses with completely consistent structures are obtained. Therefore, the method can improve the understanding of the mechanical properties and the failure rule of the rock mass with the complex fracture structure, and provides reference for the related design and safety and stability evaluation of rock mass engineering.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (7)

1. A3D printing reconstruction method of a fractured rock mass is characterized by comprising the following steps:
carrying out uniaxial compression mechanical test on the rock mass in the natural fracture structure rock mass to obtain the stress-strain mechanical property and the failure property of the rock mass;
carrying out shearing and tensile tests on a structural surface in a natural fractured structure rock mass to obtain the structural surface shearing and tensile mechanical properties and destruction characteristics of the fractured structure rock mass;
determining the mechanical property similarity ratio of the rock mass and the structural surface of the 3D-printed reconstructed fractured structure rock;
selecting a rock 3D printing material and ensuring similarity;
selecting a 3D printing material and designing a structure;
3D modeling and outputting of a fractured rock mass;
structural surface 3D prints material selection and structural design, includes:
the structural surface of the 3D printing reconstructed fractured structure rock mass is designed by adopting a net structure;
three-dimensional point cloud data are obtained by three-dimensionally scanning the wall surface fluctuation degree of the rock mass with the natural fracture structure;
completing structural surface wall surface structure printing of the 3D printing reconstructed fracture structure rock mass according to the mesh structure design and the three-dimensional point cloud data;
carrying out shearing and tensile tests on the structural surface of the 3D printing reconstructed fractured structure rock mass, and verifying the effectiveness of the 3D printing reconstructed fractured structure rock mass network structure design through similarity comparison of test results;
the structural surface of the fractured rock mass is designed by adopting a net structure, and the specific method comprises the following steps:
if the reconstitution size is
Figure FDA0002450060050000012
The standard size structural surface sample of (2), the cross-sectional area of the standard size structural surface sample is:
Figure FDA0002450060050000011
in the formula: stotalIs the cross-sectional area in mm2；DtotalIs the cross section diameter in mm;
if Fullcure 720 is adopted as the material of the reconstruction structure surface in the 3D printing reconstruction process, and the tensile strength of the material is 40MPa, the tensile strength ratio R of the net-shaped structure and the Fullcure 720 on the whole section isnetComprises the following steps:
Figure FDA0002450060050000021
the total area S of the net structure of the rock mass structural planenetComprises the following steps:
Snet＝Rnet·Stotal＝0.002×1962.5＝3.93mm2(7)
if the diameter D of the connecting point of the net structure is setpoint0.2mm, the area S of each connection pointpointComprises the following steps:
Figure FDA0002450060050000022
the number N of web connection points required in the cross-sectionpointComprises the following steps:
Figure FDA0002450060050000023
if the network connection points are arranged in a square, the spacing L between the connection pointspointCan be calculated as:
Figure FDA0002450060050000024
in the aspects of 3D printing reconstruction fracture structure rock mass structural surface shearing mechanics and destruction characteristics, 3D scanning is required to be carried out on a natural rock mass structural surface, and 3D point cloud data of the wall surface fluctuation degree of the reconstruction fracture structure rock mass structural surface are obtained;
and reconstructing the rock mass structural plane on the basis of the selection of the rock mass material on the wall surface of the structural plane and the 3D scanning point cloud data by adopting a 3D printing technology.
2. The 3D printing reconstruction method of the fractured structure rock mass according to claim 1, wherein the uniaxial compression mechanical test is performed on the rock mass in the natural fractured structure rock mass, and the method comprises the following steps: carrying out uniaxial compression test of the wall rock mass, wherein:
the test rock block core is cylindrical, the diameter of the test rock block core is 50mm, and the height of the test rock block core is 100 mm;
and (4) drawing a stress-strain curve of the rock mechanical test, and analyzing the damage characteristics of the rock core of the rock.
3. The 3D printing reconstruction method of the fractured structure rock mass according to claim 1, wherein the shear and tensile test of the structural surface in the natural fractured structure rock mass comprises the following steps:
carrying out a shearing test on the structural plane of the natural fractured structure rock mass, and determining the shearing mechanical property and the destruction characteristic of the structural plane of the fractured structure rock mass;
and carrying out a tensile test on the structural surface of the natural fractured structure rock mass, and determining the tensile mechanical property and the failure characteristic of the structural surface of the fractured structure rock mass.
4. The 3D printing reconstruction method of the fractured structural rock mass according to claim 1, wherein the step of determining the mechanical property similarity ratio of the rock mass and the structural surface in the fractured structural rock mass comprises the following steps:
carrying out an on-site bearing plate test and a true triaxial test on the natural fractured structure rock mass, and determining the strength, the elastic modulus and the deformation of the natural fractured structure rock mass;
measuring the density of the natural fracture structure rock mass;
determining the similarity ratio of the physical and mechanical properties of the 3D printed reconstructed fractured structure rock mass and the natural fractured structure rock mass according to a similarity ratio formula, wherein the similarity ratio formula is as follows:
Figure FDA0002450060050000031
in the formula, CiIs the similarity ratio of the corresponding physical mechanical properties of i, wherein i is the category of the physical mechanical properties, and comprises: stress (σ), elastic modulus (E), density (γ), sample side length (L), Poisson's ratio (upsilon) and strain (ε), the iRSThe i is the category of the physical mechanical properties of the reconstructed fractured structure rock massCJBsIs the category of the physical and mechanical properties of the natural fractured rock mass,
Cσ＝CE(2)，
Cε＝Cυ＝1 (3)，
Cσ＝Cγ·CL(4)。
5. the 3D printing reconstruction method of a fractured-structure rock mass according to claim 1, wherein the rock mass 3D printing material comprises: photosensitive resin, gypsum, ceramic, epoxy resin.
6. The 3D printing reconstruction method of the fractured structure rock mass according to claim 1, wherein after the 3D printing material of the rock mass is determined, similarity verification is carried out on mechanical and destructive characteristics of the 3D printing material of the rock mass through a uniaxial compression test, so that the brittle and destructive characteristics and the mechanical characteristics of the 3D printing reconstruction fractured structure rock mass and the natural fractured structure rock mass are similar.
7. A fractured structure rock mass, which is prepared by the 3D printing reconstruction method of the fractured structure rock mass according to any one of claims 1 to 6.
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