A mold for making a non-through closed rough joint specimen and a method for making the specimen

Abstract

The present invention provides a mold for making a non-through closed rough joint specimen and a specimen making method, comprising: a shell having a housing cavity with a material injection port formed at the top; a prefabricated rubbing plate placed in the housing cavity along the length direction of the shell and dividing the internal space of the housing cavity into a first chamber and a second chamber distributed on the left and right; the prefabricated rubbing plate is made into an integral structure by 3D printing, comprising: a rock bridge portion arranged along the width direction of the shell and completely dividing the first chamber into two sub-chambers, and the rock bridge portion has a gap toward the second chamber; a rubbing plate portion, comprising a first rubbing plate and a second rubbing plate, the first rubbing plate and the second rubbing plate having joint surfaces on a side close to the second chamber, and different joint roughness and joint continuity are formed inside the specimen by two groups of the joint surfaces. Through the disclosure of the present invention, the replication of a rock structure closer to the natural state is achieved, so that the test results can better reflect the actual stress state and failure process of the engineering rock mass.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel surrounding rock control, and more particularly to a manufacturing mold for a non-through closed rough joint sample and a sample manufacturing method. Background Art

[0002] Currently, in the fields of mining and geotechnical engineering, rock bridges are widely distributed in engineering rock masses, making their failure evolution process highly gradual and sudden. In addition, there are many irregular joint surfaces in the rock mass. The existence of these joint surfaces determines the nonlinearity and anisotropy of the mechanical properties of the rock mass, which in turn makes the rock mass properties inherently uncertain. In addition, research on the interaction between rock bridges and joint surfaces is very scarce. Therefore, the production of closed discontinuous joints that are more consistent with natural rock masses has become the basis for solving the above problems. Since the distribution of natural rock joints and fissures is relatively scattered, it is impossible to accurately obtain accurate mechanical parameters. It is often necessary to use highly plastic materials such as cement to prefabricate rock-like materials, and the test samples need to be made into specimens with specific joint roughness and joint continuity to conduct relevant experimental research. The preparation of such rock samples is particularly important.

[0003] Current specimen preparation molds and methods typically reduce pore openings to approximate closed joints, or employ splitting methods to create rock-like specimens. This makes it difficult to create closed joints with a specific joint roughness and continuity. This, to a certain extent, limits systematic experimental research. Furthermore, specimen preparation molds are often cumbersome to disassemble and inconvenient to clean.

[0004] To address these technical issues, the present invention provides a mold and method for fabricating specimens with non-through, closed, rough joints. This mold and method demonstrate significant economic efficiency, ease of operation, mass production capabilities, and precise control of joint roughness and continuity, making them of great value for studying the properties of rock materials containing non-continuous joints. Summary of the Invention

[0005] The purpose of the present invention is to disclose a mold and a method for making non-penetrating closed rough joint samples, which effectively solves the current situation that non-penetrating closed rough jointed rock masses with specific joint roughness and joint continuity cannot be made in existing sample making methods, and the problem that the operation of making samples using the making mold is too cumbersome, and realizes the casting of non-penetrating closed jointed rock samples with specific joint roughness and joint continuity, effectively improves the accuracy and integrity of the samples, and makes the operation process simpler.

[0006] To achieve the above object, the present invention provides a mold for making a non-through closed rough joint specimen, comprising:

[0007] The shell has a receiving cavity with a material injection port formed at the top;

[0008] A prefabricated extension plate is placed in the accommodating cavity along the length direction of the shell, and divides the internal space of the accommodating cavity into a first chamber and a second chamber, so as to form a joint surface between the cast samples;

[0009] It is characterized in that the prefabricated rubbing plate is manufactured into an integral structure by 3D printing, including:

[0010] a rock bridge portion, arranged along the width direction of the shell, and completely dividing the first chamber into two sub-chambers, and the rock bridge portion has a gap toward the second chamber;

[0011] The rubbing plate portion includes a first rubbing plate and a second rubbing plate. The first rubbing plate and the second rubbing plate are both located on the center line of the accommodating cavity and distributed on both sides of the rock bridge portion along the length direction of the accommodating cavity. The first rubbing plate and the second rubbing plate have joint surfaces on the side close to the second cavity. Different joint roughness and joint continuity are formed inside the sample through two groups of joint surfaces.

[0012] As a further improvement of the present invention, the prefabricated rubbing plate can be used to produce joint surfaces with different joint roughness and different joint continuity through 3D printing.

[0013] As a further improvement of the present invention, a serrated protrusion is provided on a side of the notch facing the second cavity.

[0014] As a further improvement of the present invention, the housing includes:

[0015] Base plate, two long side plates and two wide side plates, and fixing connectors;

[0016] The two long side panels and the two wide side panels are symmetrically spaced and fixed on the bottom plate, and enclose a rectangular accommodating cavity;

[0017] The fixed connection member comprises:

[0018] Two sets of connecting bolts are symmetrically arranged on both sides of the long side plates, used to connect and fix the two long side plates, with both ends of the connecting bolts respectively passing through the bolt holes opened in the center of the outer ends of the two long side plates and fixed by nuts;

[0019] A first fixing seat arranged at the center of the outer top ends of the two long side panels;

[0020] a second fixing seat arranged on the bottom plate and located below the first fixing seat;

[0021] a rotatable connecting rod connecting the first fixing base and the second fixing base;

[0022] The rotating connecting rod is in an inverted T shape, with the bottom end passing through the second fixing seat to form a rotating connection, and the top end being fixed to the first fixing seat through a nut.

[0023] As a further improvement of the present invention, two first grooves are provided on the bottom plate in a spaced-apart parallel manner along the length direction, and the first grooves are provided for the bottom ends of the long side panels to be embedded in. Second grooves are provided at both ends of the opposite side of the long side panels, and the second grooves are provided for the side ends of the wide side panels to be embedded in.

[0024] As a further improvement of the present invention, a positioning structure is further included for limiting and fixing the prefabricated extension plate during the pouring process of the second cavity.

[0025] As a further improvement of the present invention, the positioning structure is four supporting legs, which are arranged in the first cavity and fixed between the four corners of the prefabricated rubbing board and the shell, respectively, for supporting the prefabricated rubbing board in the width direction.

[0026] The present invention also discloses a method for manufacturing a non-through closed rough joint sample based on a manufacturing mold for a non-through closed rough joint sample, comprising the following steps:

[0027] S1, pouring the prepared cement mortar into the second chamber, and after the test block solidifies and takes shape, removing the prefabricated rubbing board and applying a water-repellent red synthetic resin emulsion paint on the joint surface of the test block to complete the first part of the sample;

[0028] S2, pouring cement mortar into the remaining space in the shell to form the sample into a predetermined size, and demoulding after solidification to complete the second part of the sample;

[0029] S3, place the sample in a constant temperature and humidity curing box for standard curing, and complete the preparation after polishing.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) A mold for making non-through closed rough joint specimens uses 3D printing to produce joint surfaces with specific joint roughness and joint continuity, effectively solving the problem that joint surfaces generated by splitting cannot be quantified and replicated. Compared with existing technologies, this technology can achieve the replication of rock structures that are closer to the natural state in the laboratory, so that the test results can better reflect the actual stress state and failure process of the engineering rock mass.

[0032] (2) A serrated protrusion is provided on the side of the notch of the rock bridge portion facing the second cavity, which ensures that during the test of the specimen, the end of the specimen corresponding to the protrusion will not slip, causing damage to the specimen and thus affecting the test data.

[0033] (3) The specimen preparation method adopts a two-time casting method to achieve complete closure of the joint surface and the problems of joint roughness and joint continuity. Since the specimen relies on the long side plate, wide side plate and bottom plate in the two castings, the flatness of the specimen is guaranteed, avoiding the bias phenomenon caused by unevenness during the test and affecting the test results, and can better simulate the stress state of constant normal load in the natural state.

[0034] (4) After the first part was poured, a water-repellent red synthetic resin emulsion paint was applied to the joint surface, ensuring that the second part would not bond with the joint surface of the first part after pouring, thereby ensuring that the strength of the joint surface is completely provided by the rough concave and convex parts of the joint surface, eliminating the influence of the cohesion generated by the bonding of the joint surface.

[0035] (5) The various parts of the mold can be completely disassembled and separated, which is easy to assemble and use, and is conducive to cleaning and storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A three-dimensional diagram of a mold for making a non-through closed rough joint specimen according to the present invention;

[0037] Figure 2 This is a three-dimensional diagram of a prefabricated rubbing plate in a mold for making a non-through closed rough joint specimen of the present invention;

[0038] Figure 3 This is a top view of the rubbing plates with different joint roughness and different joint continuity of the mold for making non-through closed rough joint specimens of the present invention, indicating that rubbing plates with different roughness and continuity can be made according to the test plan, where JRC represents the joint roughness and k represents the joint continuity.

[0039] In the figure: 1. Base plate; 2. Long side plate; 3. Wide side plate; 4. Connecting bolts; 5. Rotating connecting rod; 6. Second fixing seat; 7. First fixing seat; 8. Nut; 9. Prefabricated rubbing plate; 10. Support leg; 91. Joint surface; 92. Rock bridge part; 911. First rubbing plate; 912. Second rubbing plate; 920. Notch; 921. Protrusion. DETAILED DESCRIPTION

[0040] The present invention is described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in this field based on these embodiments are all within the scope of protection of the present invention.

[0041] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0042] In the description of this application, it should be understood that the terms "first," "second," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first," "second," etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0043] Please refer to Figures 1 to 3 A specific embodiment of a mold for making a non-through closed rough joint specimen of the present invention is shown.

[0044] Ginseng Figure 1 As shown, a mold for making non-through closed rough joint specimens includes: a shell, the shell has a accommodating cavity with an injection port formed at the top; the shell includes: a bottom plate 1, two long side plates 2 and two wide side plates 3, and a fixed connecting piece; the two long side plates 2 and the two wide side plates 3 are symmetrically fixed on the bottom plate 1 and enclosed to form a rectangular accommodating cavity; two first grooves are opened on the bottom plate 1 along the length direction, and the first groove is for the bottom end of the long side plate 2 to be embedded, and second grooves are opened at both ends of the opposite side of the long side plate 2, and the second grooves are for the side ends of the wide side plate 3 to be embedded.

[0045] The fixed connection parts include: two sets of connecting bolts 4, symmetrically arranged on both sides of the long side plates 2, used to connect and fix the two long side plates 2, with the two ends of the connecting bolts 4 respectively passing through the bolt holes opened in the center of the outer ends of the two long side plates 2 and fixed by nuts 8; a first fixing seat 7 arranged in the center of the top end of the outer sides of the two long side plates 2; a second fixing seat 6 arranged on the bottom plate 1 and located below the first fixing seat 7; a rotating connecting rod 5 connecting the first fixing seat 7 and the second fixing seat 6; the rotating connecting rod 5 is in an inverted T shape, and the bottom end passes through the second fixing seat 6 to form a rotating connection, and the top end is fixed to the first fixing seat 7 by a nut 8. Two second fixing seats 6 are arranged in parallel, and a through hole is opened in the same axis. The rotating connecting rod 5 is passed through the through holes on the two second fixing seats 6, and by setting fixing bolts at both ends, the top end of the rotating connecting rod 5 is connected to the first fixing seat 7 at the same time, and the nut 8 is tightened to complete the production of the shell.

[0046] Ginseng Figure 2As shown, the prefabricated rubbing plate 9 is placed in the accommodating cavity along the length direction of the shell, and divides the internal space of the accommodating cavity into a first chamber and a second chamber to form a joint surface 91 between the cast samples; the prefabricated rubbing plate 9 is made into an integral structure by 3D printing, including: a rock bridge portion 92, which is arranged along the width direction of the shell and completely divides the first chamber into two sub-chambers, and the rock bridge portion 92 is provided with a gap 920 toward the second chamber; a rubbing plate portion, including a first rubbing plate 911 and a second rubbing plate 912, the first rubbing plate 911 and the second rubbing plate 912 are both located on the center line of the accommodating cavity and distributed on both sides of the rock bridge portion 92 along the length direction of the accommodating cavity, the first rubbing plate 911 and the second rubbing plate 912 have a joint surface 91 on the side close to the second chamber, and different joint roughness and joint continuity are formed inside the sample through two groups of joint surfaces 91.

[0047] The support legs 10 are arranged in the first cavity and fixed between the four corners of the prefabricated rubbing plate 9 and the shell to support the prefabricated rubbing plate 9 in the width direction. The prefabricated rubbing plate 9 can be made into joint surfaces 91 with different joint roughness and different joint continuity by 3D printing. Figure 3 The continuity of the joint is calculated as the ratio of the length of the joint to the total length. The continuity is changed by changing the length of the intermediate rock bridge 92. A serrated protrusion 921 is provided on the side of the notch 920 facing the second cavity.

[0048] The present invention also discloses a method for manufacturing a non-through closed rough joint specimen based on a mold for manufacturing a non-through closed rough joint specimen, comprising the following steps: S1, pouring a pre-prepared cement mortar into a second chamber, and after the specimen is solidified and formed, taking out the prefabricated rubbing plate 9, and applying a water-proof red synthetic resin emulsion paint on the joint surface 91 of the specimen to complete the first part of the specimen; S2, pouring cement mortar into the remaining space in the shell to form the specimen into a predetermined size, and demolding after solidification to complete the second part of the specimen; S3, placing the specimen in a constant temperature and humidity curing box for standard curing, and polishing it to complete the preparation.

[0049] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A mold for making a non-through closed rough joint specimen, comprising: The shell has a receiving cavity with a material injection port formed at the top; A prefabricated extension plate is placed in the accommodating cavity along the length direction of the shell, and divides the internal space of the accommodating cavity into a first chamber and a second chamber, so as to form a joint surface between the cast samples; It is characterized in that the prefabricated rubbing plate is manufactured into an integral structure by 3D printing, including: a rock bridge portion arranged along the width direction of the housing and completely dividing the first chamber into two sub-chambers, the rock bridge portion having a notch formed toward the second chamber; and a serrated protrusion provided within the notch on a side facing the second chamber; A rubbing plate portion, comprising a first rubbing plate and a second rubbing plate, wherein the first rubbing plate and the second rubbing plate are both located on the center line of the accommodating cavity and are distributed on both sides of the rock bridge portion along the length direction of the accommodating cavity, and the first rubbing plate and the second rubbing plate have joint surfaces on a side close to the second cavity, and different joint roughness and joint continuity are formed inside the specimen through the two groups of joint surfaces; It also includes a positioning structure, which is arranged in the accommodating cavity and is used to limit and fix the prefabricated extension plate during the pouring process of the second cavity.

2. A mold for making a non-through closed rough joint specimen according to claim 1, characterized in that: The prefabricated rubbing plate can be used to produce joint surfaces with different joint roughness and different joint continuity through 3D printing.

3. The mold for making a non-through closed rough joint specimen according to claim 1, characterized in that: The housing comprises: Base plate, two long side plates and two wide side plates, and fixing connectors; The two long side panels and the two wide side panels are fixedly mounted on the bottom plate at symmetrical intervals and enclose a rectangular accommodating cavity; The fixed connection member comprises: Two sets of connecting bolts are symmetrically arranged on both sides of the long side plates, used to connect and fix the two long side plates, with both ends of the connecting bolts respectively passing through the bolt holes opened in the center of the outer ends of the two long side plates and fixed by nuts; A first fixing seat arranged at the center of the outer top ends of the two long side panels; a second fixing seat arranged on the bottom plate and located below the first fixing seat; a rotatable connecting rod connecting the first fixing base and the second fixing base; The rotating connecting rod is in an inverted T shape, with the bottom end passing through the second fixing seat to form a rotating connection, and the top end being fixed to the first fixing seat through a nut.

4. A mold for making a non-through closed rough joint specimen according to claim 3, characterized in that: Two first grooves are arranged in parallel and spaced apart along the length direction on the bottom plate, and the bottom ends of the long side plates are embedded in the first grooves. Second grooves are respectively provided at the two ends of the opposite side of the long side plates, and the side ends of the wide side plates are embedded in the second grooves.

5. The mold for making a non-through closed rough joint specimen according to claim 1, characterized in that: The positioning structure is four supporting legs, which are arranged in the first cavity and fixed between the four corners of the prefabricated rubbing plate and the shell, and are used to support the prefabricated rubbing plate in the width direction.

6. A method for producing a non-penetrating closed rough joint sample based on a production mold for a non-penetrating closed rough joint sample according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, pouring the prepared cement mortar into the second chamber, and after the test block solidifies and takes shape, removing the prefabricated rubbing board and applying a water-repellent red synthetic resin emulsion paint on the joint surface of the test block to complete the first part of the sample; S2, pouring cement mortar into the remaining space in the shell to form the sample into a predetermined size, and demoulding after solidification to complete the second part of the sample; S3, place the sample in a constant temperature and humidity curing box for standard curing, and complete the preparation after polishing.

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