Mold for making rock-like material containing internal prefabricated cracks and method for making cracks

Abstract

The application discloses a kind of preparation of the mold of internal prefabricated crack rock-like material and crack preparation method, mold includes rock-like sample mold (1), bottom die (2) and prefabricated crack mold (3), the rock-like sample mold (1) includes first side mold (11) and second side mold (12), side mold center is equipped with positioning long round hole (13), positioning bolt (14) can be fixed thereon, its outside is provided with angle height mark (15);The prefabricated crack mold (3) includes threading platform (33), for fixing cotton thread (34), after water injection freezing, ice prefabricated crack (37) with the cotton thread (34) is made, the cotton thread (34) at its two ends is tied on the positioning bolt (14) at different positions of the rock-like sample mold (1), that is, different angle and interval prefabricated crack can be formed.The application has simple structure, is easy to use, and is suitable for making rock-like sample with different prefabricated crack number, angle and interval.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geotechnical engineering, and more particularly relates to a mold for manufacturing rock material containing internal prefabricated cracks and a crack manufacturing method. BACKGROUND

[0002] Rock mass is widely used as an engineering material in engineering structures such as buildings, roads, bridges, tunnels and dam bodies. However, cracks often exist inside the rock mass. The cracks of different sizes inside the rock mass expand and penetrate under external force, causing the rupture of the rock mass and the destruction and instability of the engineering structure, which has an impact on the engineering. Therefore, the research on the cracks inside the rock mass and the expansion mechanism thereof is of great significance for preventing and controlling the rupture of the rock mass and the destruction of the engineering structure.

[0003] At present, indoor tests are mainly used to study the expansion mechanism of cracks inside the rock mass. By manufacturing different rock samples, the initiation, expansion and penetration mechanism of cracks under different conditions can be systematically studied to provide basic data for understanding the rock mass failure process. Therefore, the manufacturing of rock samples containing internal cracks is crucial. In the prior art, the original rock sample is cut to form, and then the internal cracks are manufactured, such as the patent document with publication number CN201710116338.7, which provides a manufacturing method of internal prefabricated cracks of rock samples, comprising the following steps: step one, cutting of the rock sample; step two, crack manufacturing: prefabricated crack processing is performed using a machine tool or a water jet, drilling is performed on the two end faces of the sample unit, i.e. the cutting faces of the rock sample, and then cracks are formed; step three, splicing of the sample unit; step four, curing of the spliced sample: after splicing is completed, normal pressure evaporation curing is adopted, after curing is completed, the spliced sample is placed and air dried under natural conditions, and then the high-strength cement protruding from the surface of the spliced sample is removed using fine sandpaper or a wet cloth. This method is low in cost and convenient to manufacture, and can be mass-produced. However, the prefabricated crack manufacturing method is a cutting method, which has high requirements for cutting machinery and high manufacturing cost of the sample. Moreover, the final rock sample is spliced by high-strength cement, which has an impact on the integrity of the rock sample, and the manufacturing of the intact rock sample is difficult. For example, the patent document with publication number CN201410019613.X discloses a true triaxial rock sample crack prefabrication device, which can adjust the size of the clamping body to manufacture cracks of a predetermined number, position, size and angle on the true triaxial rock sample, and can meet the requirements of different rock sample sizes and different crack prefabrication schemes, facilitating the experimental research on the multi-crack expansion and penetration failure mechanism of the rock. The present application has the advantages of simple structure, reasonable design, convenient use, efficient and feasible crack manufacturing, and is particularly suitable for the crack prefabrication of soft rock true triaxial rock samples. However, one transparent mold is consumed for the manufacturing of one sample, which has a large consumption of molds and high cost. Moreover, the prefabricated cracks are through cracks, rather than non-penetrating cracks.

[0004] With the proposal of similar principles, researchers began to use similar materials of rock (such as gypsum, concrete) to simulate the development and penetration mechanism of internal cracks of rock. For example, the patent document with publication number CN202110832252.0 discloses a kind of adjustable rock-like material fracture prefabrication device, including base fixing mechanism, material filling mechanism and variable fracture positioning adjusting mechanism, base fixing mechanism includes base and base assembly;Material filling mechanism includes bearing seat and filling mold;The filling mold is a rectangular cylinder with adjustable length and width;Variable fracture positioning adjusting mechanism includes fracture positioning plate, fracture body assembly and fracture positioner, the number of fracture body assembly and fracture positioner is determined by the number of rock-like material fracture preparation, fracture body assembly is vertically arranged between fracture positioning plate and bearing seat, and the bottom of fracture body assembly is detachably connected with the recess intersection point of bearing seat.This application can prefabricate cracks of different lengths, widths, numbers, spacings and pattern sizes for rock-like materials, providing convenience for sample preparation in rock mechanics tests.However, the device is achieved by setting fracture bodies, which has a certain influence on the study of crack propagation and penetration mechanism.In the prior art, a large number of samples are needed for rock mechanics tests, and there are many difficulties in sampling and preparing rock samples.In similar material samples, mica sheets, iron sheets and other solid substances are usually used to simulate cracks, which have certain limitations, such as greater influence on the study of crack propagation and penetration mechanism, and the existing mold technology has problems such as large mold consumption, high production cost, insufficient precision, inflexible design and use of mold, and difficulty in meeting the needs of crack simulation of different angles, numbers and spacings.In order to more accurately simulate and study the behavior of internal cracks of rock, it is necessary to accurately control the number, spacing and angle of cracks, and the existing technology cannot meet this demand. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a mold for making rock-like material containing internal prefabricated cracks and a crack making method, which can prefabricate cracks that meet different test requirements through a prefabricated crack mold, fix the prefabricated cracks on positioning bolts at different positions through the angle and height markings of the rock-like sample mold and the positioning bolts, and pour similar materials in the cavity of the mold to form rock-like samples containing prefabricated cracks of different numbers, angles and spacings.

[0006] In order to achieve the above purpose, according to one aspect of the present application, a mold for making rock-like material containing internal prefabricated cracks is provided, which includes a rock-like sample mold for making similar material samples, a bottom mold and a prefabricated crack mold for making prefabricated cracks, wherein,

[0007] The rock-like sample mold comprises a first side mold and a second side mold, both of which are provided with a positioning long circular hole at the center position, and a positioning bolt is fixed on the positioning long circular hole; and an angle height mark is arranged outside the positioning long circular hole according to the number, angle and interval of the prefabricated cracks.

[0008] The prefabricated crack mold comprises a water containing device and a water injection channel, and a threading platform is arranged at the joint of the water containing device and the water injection channel, the threading platform is a cylinder provided with a notch, and is used for fixing a cotton thread; the prefabricated crack mold is frozen after water injection, and the prefabricated crack with the cotton thread is formed; the cotton thread at both ends of the prefabricated crack is tied to the positioning bolt at different positions of the rock-like sample mold, and the similar material is poured into the cavity of the rock-like sample mold, so that the rock-like sample with different numbers, angles and intervals of prefabricated cracks is formed.

[0009] Further, the rock-like sample mold further comprises a first baffle and a second baffle, which are used for closing the positioning long circular hole on the first side mold and the second side mold to form a pouring cavity closed on the side, and the cotton thread passes through the middle of the first baffle and the second baffle.

[0010] Further, the rock-like sample mold further comprises a fastening belt used for fastening the top and bottom ends of the rock-like sample mold.

[0011] Further, the contact part of the first side mold and the second side mold is respectively designed as a concave-convex groove with a width and a height of 1mm-5mm, so as to ensure that the splicing part is tight and does not leak mortar.

[0012] Further, the bottom mold comprises a circular groove used for placing the first side mold and the second side mold of the rock-like sample mold.

[0013] Further, the prefabricated crack mold further comprises a thickness mark arranged on the inner side wall of the water containing device, which is used for determining the thickness of the prefabricated crack.

[0014] Further, the prefabricated crack mold further comprises a crack baffle used for adjusting the water level in the water containing device by adjusting the opening of the crack baffle according to the test requirement.

[0015] Further, the rock-like sample mold can be a cylinder or a cuboid or a shape adjusted according to the test requirement.

[0016] Further, the shape of the prefabricated crack mold is adjusted according to the test requirement, and is matched with the rock-like sample mold.

[0017] According to another aspect of the present application, a crack making method of a rock-like material with internal prefabricated cracks is provided, which is realized by using the mold for making a rock-like material with internal prefabricated cracks, and comprises the following steps:

[0018] S100:Preparation of similar materials of rock sample;

[0019] S200:Preparation of pre-crack by pre-crack mold, first, the fine cotton thread is threaded through the threading platform, then the crack baffle is installed, then water is injected in the center of the pre-crack mold, the water level reaches the required thickness mark, and the injection is stopped, the whole pre-crack mold is placed in the refrigerator for freezing, after freezing, the pre-crack mold is taken out together with the fine cotton thread, the pre-crack is obtained, then the pre-crack is placed in the refrigerator for freezing, and the same method can be used to make different thickness pre-cracks for standby;

[0020] S300:According to the number, angle and spacing of the designed pre-crack, the angle height mark is determined by calculation, the positioning bolt is screwed into the positioning long hole for fixation on the first side mold according to the angle mark, then the positioning bolt is screwed into the positioning long hole and fixed at another position according to the height mark, then the fine cotton thread on the pre-crack is tied to the positioning bolt, and the first baffle and the second baffle of the first side mold are immediately installed, the same operation is performed on the second side mold; while tying the fine cotton thread, the first side mold and the second side mold are slowly spliced along the slot, and the spliced rock-like mold is placed in the circular groove of the bottom mold and fastened with the fastening belt to form a pouring cavity;

[0021] S400:Pouring similar materials into the cavity, and after vibration, curing and demolding, uniaxial and triaxial rock-like samples containing different numbers, angles and spacings of internal real pre-cracks can be obtained.

[0022] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0023] 1. The pre-crack mold of the present application can accurately make pre-cracks of different thicknesses through thickness marks, and since the pre-crack is made of ice, the real pre-crack is formed in the rock sample, which is more valuable for studying the real internal crack propagation mechanism of rock mass;

[0024] 2. The rock-like sample mold structure of the present application can fix the ice pre-crack on the positioning bolt at different positions by setting the angle height mark and the positioning bolt on the mold, and pour similar materials in the mold cavity, so as to make uniaxial and triaxial samples containing different pre-crack angles, different pre-crack spacings and different pre-crack numbers, which is simple in operation, improves the test efficiency and reduces the sample preparation time and difficulty;

[0025] 3. The rock-like sample mold of the present application can not only be made into a cylindrical shape, but also can be made into a cubic shape, so as to meet the requirements of true triaxial test and different shaped rock samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the three-dimensional structure of a mold for making a rock-like material with internal prefabricated cracks according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of a rock sample mold according to an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the three-dimensional structure of the bottom mold according to an embodiment of the present invention;

[0029] Figure 4 This is a right side view of the first side mold without the baffle installed in the embodiment of the present invention;

[0030] Figure 5 This is a right side view of the first side mold when the baffle is installed in the embodiment of the present invention;

[0031] Figure 6 Schematic diagram of the three-dimensional structure of the prefabricated crack mold according to an embodiment of the present invention;

[0032] Figure 7 This is a prefabricated crack after the embodiment of the present invention is completed;

[0033] Figure 8 A cross-sectional view of a prefabricated crack installed in a rock-like specimen mold according to an embodiment of the present invention;

[0034] Figure 9 The angle marking production principle of the embodiment of the present invention is as follows;

[0035] Figure 10 The principle of manufacturing the height mark of the embodiment of the present invention is shown;

[0036] Figure 11 Schematic diagram of a method for producing a rock-like material containing internal prefabricated cracks according to an embodiment of the present invention.

[0037] In all the drawings, the same reference numerals represent the same technical features, specifically: 1-type rock sample mold, 11-first side mold, 12-second side mold, 13-positioning oblong hole, 14-positioning bolt, 15-angle height mark, 16-fastening belt, 17-first baffle, 18-second baffle, 2-bottom mold, 21-circular groove, 3-prefabricated crack mold, 31-water holding device, 32-water injection channel, 33-threading platform, 34-fine cotton thread, 35-thickness mark, 36-crack baffle, 37-prefabricated crack. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the present application with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0039] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0040] In addition, if the embodiments of the present application involve descriptions of "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes and should not be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features with "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the realization of a person skilled in the art, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0041] In this patent, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0042] As Figures 1-8As shown, the embodiment of the present application provides a mold for making rock-like material with internal prefabricated cracks, which comprises a rock-like sample mold 1, a bottom mold 2 and a prefabricated crack mold 3. The rock-like sample mold 1 is installed in the groove of the bottom mold 2 to form a similar material pouring cavity. The prefabricated crack mold 3 can be used to make ice prefabricated cracks with different thicknesses. According to the design of the number, angle and spacing of the prefabricated cracks, the position of the ice prefabricated cracks on the rock-like sample mold 1 is adjusted and fixed, and then the similar material is poured to form a rock-like sample with internal prefabricated cracks. The uniaxial and triaxial compression test samples with different prefabricated crack angles, different prefabricated crack spacings and different prefabricated crack numbers are realized. The prefabricated crack mold is used to realize the purpose of making real prefabricated cracks, so it is more valuable for studying the real rock mass internal crack propagation mechanism. Among them,

[0043] As shown in Figure 3 , the bottom mold 2 for making rock samples is a stainless steel plate with a length of 100 mm, a width of 100 mm and a thickness of 10 mm. A circular groove 21 with an outer diameter of 60 mm (diameter), an inner diameter of 50 mm (diameter) and a depth of 8 mm is arranged at the center of the bottom mold 2 for placing the rock-like sample mold 1.

[0044] As shown in Figure 2 , the rock sample model with prefabricated cracks made by the embodiment of the present application has a cylindrical shape with a diameter of 50 mm and a height of 100 mm. The rock-like sample mold 1 comprises a first side mold 11, a second side mold 12, a positioning long circular hole 13, a positioning bolt 14, an angle height mark 15, a fastening belt 16, a first baffle 17 and a second baffle 18. The first side mold 11 and the second side mold 12 are semicircular grooves with a thickness of 10 mm and a length of 108 mm. The inner diameter (diameter) of the groove is 50 mm. The first side mold 11 and the second side mold 12 can be spliced to form a cylinder with an inner cavity size of 50 mm in diameter and 108 mm in height. The contact parts are designed with concave-convex parts with a width and height of 5 mm to ensure tight splicing without leakage. After splicing, the first side mold 11 and the second side mold 12 are placed in the circular groove 21 at the center of the bottom mold 2, and the top and bottom ends are fastened with the fastening belt 16. In this way, a cylinder with an inner cavity size of 50 mm in diameter and 100 mm in height is formed, i.e. the shape of a standard cylindrical sample. The first side mold 11 and the second side mold 12 are provided with the positioning long circular hole 13 with a width of 5 mm and a length of 80 mm at the center, on which the positioning bolt 14 can be fixed. The angle height mark 15 is arranged outside the positioning long circular hole 13. By setting the angle height mark 15 of the first side mold 11 and the angle height mark 15 of the second side mold 12, and then screwing the positioning bolt 14 into the set angle height mark, the number, angle and spacing of the prefabricated cracks can be controlled, so as to form prefabricated cracks with different numbers, angles and spacings.

[0045] As Figure 6 , 7 shown, the prefabricated crack mold 3 includes water container 31, water injection channel 32, threading platform 33, cotton thread 34, thickness identifier 35, crack baffle 36 and prefabricated crack 37;

[0046] The water container 31 is a cylindrical water container with an inner diameter (diameter) of 10 mm, an outer diameter of 12 mm and a height of 8 mm, and two water injection channels 32 with a width of 2 mm and a length of 15 mm are connected to both sides of the water container 31. The material of the water container 31 and the water injection channel 32 is stainless steel, and the thickness is 2 mm, which is used to form a cylindrical prefabricated crack 37 by injecting water. A crack baffle 36 and a threading platform 33 with a diameter of 1 mm and a height of 8 mm are respectively arranged at the junction of the water container 31 and the water injection channel 32. The crack baffle 36 can form a complete cylindrical water container with the water container 31. The threading platform 33 is a cylindrical body with a partial gap, which is mainly used to facilitate the fixation of the cotton thread 34 to realize the integration of the cotton thread 34 and the prefabricated crack 37. The prefabricated crack 37 is a cylindrical ice piece with a diameter of 10 mm and a height of 5 mm. The thickness identifier 35 is arranged on the inner side wall of the water container 31. The thickness of the cylindrical ice piece prefabricated crack can be adjusted by adjusting the opening of the crack baffle 36 to adjust the water level in the water container 31, and the thickness required for the test can be determined by checking the thickness identifier 35. The specific shape of the cylindrical ice piece prefabricated crack can also be adjusted by adjusting the shape of the mold.

[0047] As Figure 8 shown, by tying the cotton thread 34 on the prefabricated crack 37 to the positioning screw 14 at different positions of the first side mold 11 and the second side mold 12, and then installing the first baffle 17 and the second baffle 18 on both sides of the positioning long circular hole 13 of the first side mold 11 and the second side mold 12 to close the side plate, a single-axis, triaxial rock sample containing different number, angle and spacing prefabricated cracks can be made by pouring similar materials in the mold pouring cavity. The cotton thread 34 can pass through the middle of the first baffle 17 and the second baffle 18.

[0048] In combination Figures 1-8 , as Figure 11 shown, the present application proposes a method for making internal prefabricated crack rock material, which is a single-axis, triaxial rock sample containing different number, angle and spacing prefabricated cracks prepared by the above mold. The specific steps are as follows:

[0049] S100: prepare similar materials for rock sample;

[0050] S200: Using a prefabricated crack mold to make a prefabricated crack, first, pass a thin cotton thread through a threading platform, then install a crack baffle, then inject water into the center of the prefabricated crack mold, stop injecting water after the water level reaches the required thickness mark, put the entire prefabricated crack mold into a refrigerator and freeze it, after freezing, put the prefabricated crack mold into warm water for a few seconds, take out the prefabricated crack together with the thin cotton thread to obtain a prefabricated crack, and then put the prefabricated crack into a refrigerator and freeze it for later use. By following this method, prefabricated cracks of various thicknesses can be made for later use;

[0051] S300: According to the number, angle, and spacing of the designed prefabricated cracks, the angle height mark is determined by calculation, and the positioning bolts are screwed into the positioning oblong holes on the first side mold according to the angle mark to fix them. Then, after selecting another position according to the height mark, the positioning bolts are screwed into the positioning oblong holes and fixed. Then, the fine cotton thread on the prefabricated cracks is tied to the positioning bolts, and the first baffle and the second baffle of the first side mold are immediately installed. The same operation is performed on the second side mold; while tying the fine cotton thread, the first side mold and the second side mold are slowly spliced ​​together along the notch, and the spliced ​​rock sample mold is placed in the circular groove of the bottom mold and fastened with a fastening belt to form a casting cavity;

[0052] S400: Similar materials are poured into the cavity, and after vibration, curing and demolding, uniaxial and triaxial rock samples with real prefabricated cracks in different numbers, angles and spacings can be obtained.

[0053] The following further discloses a specific embodiment of the present invention based on a method for producing a rock material containing internal prefabricated cracks.

[0054] An embodiment 1 of the present invention:

[0055] like Figure 9 As shown, this embodiment of the present invention provides a method for producing a rock material containing internal prefabricated cracks, specifically using the above mold to prepare a rock sample containing a prefabricated crack with a single angle A, and the specific steps include:

[0056] S100: Prepare similar materials for rock samples;

[0057] S200: using a prefabricated crack mold to make a prefabricated crack, first passing a thin cotton thread through a threading platform, then installing a crack baffle, then injecting water into the center of the prefabricated crack mold, stopping the water injection after the water level reaches the required thickness mark, placing the entire prefabricated crack mold in a refrigerator to freeze, after freezing, placing the prefabricated crack mold in warm water for a few seconds, taking out the prefabricated crack together with the thin cotton thread to obtain a borneol prefabricated crack, and then placing the prefabricated crack in a refrigerator to freeze for standby use. The same method can be used to make prefabricated cracks of various thicknesses for standby use;

[0058] S300: first according to the angle mark principle to determine the angle mark on the first side mold and the second side mold, the principle of making the angle mark is: the angle A is the angle between the prefabricated crack and the horizontal X direction, the inner diameter of the rock sample mold is 50mm, the mold center is the boundary, then the distance between the two ends of the prefabricated crack is 50mm x tan A on the first side mold and the second side mold, and the angle mark is made on the first side mold and the second side mold;

[0059] In the first side mold, first according to the angle mark, the positioning bolt is screwed into the positioning long round hole for fixation, then the ice piece prefabricated crack is taken out from the refrigerator, the fine cotton line 34 on the prefabricated crack is tied on the positioning bolt, and the first baffle and the second baffle of the first side mold are immediately installed; similarly, in the second side mold, according to the angle mark, the positioning bolt 14 is screwed into the positioning long round hole for fixation, then the fine cotton line at the other end of the ice piece prefabricated crack is tied on the positioning bolt of the second side mold, the first baffle and the second baffle of the second side mold 12 are immediately installed, the fine cotton line is tied at the same time, and the first side mold and the second side mold are slowly spliced along the slot, and the length of the fine cotton line on both sides of the prefabricated crack should be kept consistent during the process, so that the prefabricated crack is guaranteed to be in the center position of the rock sample, then the spliced first side mold and second side mold are placed in the circular groove of the bottom mold and the similar rock sample mold is fastened at the top and bottom ends with a fastening belt, forming a pouring cavity containing a prefabricated crack.

[0060] S400: pour the similar material into the cavity, and after vibration, curing and demolding, a uniaxial and triaxial rock sample containing a single internal prefabricated crack with an angle A can be obtained.

[0061] Another embodiment 2 of the application:

[0062] As Figure 10 shown, in this embodiment of the application, a method for making a rock sample containing an internal prefabricated crack is provided, specifically, a uniaxial and triaxial rock sample containing different angles E, F and a distance D between them is prepared by using the above-mentioned mold, and the specific steps include:

[0063] S100: preparing similar material of rock sample;

[0064] S200: using a prefabricated crack mold to make a prefabricated crack, first threading the fine cotton line through the threading platform, then installing the crack baffle, then pouring water in the center of the prefabricated crack mold, stopping pouring when the water level reaches the required thickness mark, placing the entire prefabricated crack mold in the refrigerator for freezing, after freezing, taking out the prefabricated crack together with the fine cotton line after soaking in warm water for a few seconds, obtaining an ice piece prefabricated crack, then placing the prefabricated crack in the refrigerator for standby, and multiple prefabricated cracks with different thicknesses can be prepared for standby.

[0065] S300: first according to the angle height mark principle to determine the angle height mark on the first side mold and the second side mold, the principle of making the angle height mark is: the angle E, F is the angle between the prefabricated crack and the horizontal X direction, the interval refers to the distance between the centers of the two prefabricated cracks in the vertical direction Y, the inner diameter of the mold is 50mm, the interval of the two prefabricated cracks is D, the two angles are E and F, and E is greater than F, then the interval G of the two is D-25*(tanE-tanF) on the first side mold and the second side mold, in the first side mold, first according to the angle mark, screw the positioning bolt into the positioning long circular hole and fix, then select another position according to the height mark, screw the positioning bolt into the positioning long circular hole and fix, then take out two pieces of ice sheet prefabricated crack from the refrigerator, tie the cotton thread on the prefabricated crack to the positioning bolt respectively, and immediately install the first baffle and the second baffle of the first side mold; similarly, in the second side mold, first according to the angle mark, screw the positioning bolt into the positioning long circular hole and fix, then select another position according to the height mark, screw the positioning bolt into the positioning long circular hole and fix, tie the cotton thread on the other end of the two pieces of prefabricated crack to the positioning bolt of the second side mold, immediately install the first baffle and the second baffle of the second side mold, tie the cotton thread at the same time, splice the first side mold and the second side mold along the slot, pay attention to ensure that the length of the cotton thread on both sides of the prefabricated crack should be consistent during the process, so as to ensure that the prefabricated crack is in the center position of the rock sample, then place the spliced first side mold and the second side mold in the circular groove of the bottom mold and fasten the rock-like sample mold top and bottom end with the fastening belt, to form a pouring cavity containing two prefabricated cracks.

[0066] S300: pour similar material into the cavity, and after vibration, curing and demolding, a uniaxial and triaxial rock-like sample containing two internal real prefabricated cracks with angles E and F and interval D can be obtained.

[0067] According to some specific embodiments of the present application, according to different test requirements, the rock-like sample mold is made into a cuboid shape, so that the obtained rock-like sample is a cuboid with a size of 50mm*50mm*100mm.

[0068] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A mold for making a rock-like material containing an internal preformed crack, characterized by, It comprises a rock-like sample mold (1) for making a similar material sample, a bottom mold (2), and a prefabricated crack mold (3) for making a prefabricated crack, wherein, The rock-like sample mold (1) comprises a first side mold (11) and a second side mold (12), both of which are provided with a positioning long circular hole (13) at the center position, and a positioning bolt (14) is fixed thereon, and an angle height mark (15) is provided outside the positioning long circular hole (13) according to the number, angle and spacing of the prefabricated cracks designed; The prefabricated crack mold (3) comprises a water containing device (31) and a water injection channel (32), and a threading platform (33) is arranged at the joint thereof, the threading platform (33) is a cylinder with a notch for fixing a fine cotton thread (34), and after water is injected into the prefabricated crack mold (3) and frozen, a prefabricated crack (37) with the fine cotton thread (34) is formed, and by tying the fine cotton thread (34) at both ends of the prefabricated crack (37) to the positioning bolts (14) at different positions of the rock-like sample mold (1), pouring similar material into the cavity of the rock-like sample mold (1) can form a rock-like sample containing prefabricated cracks with different number, angle and spacing.

2. A mold for making a rock-like material containing an internal prefabricated crack according to claim 1, characterized by The rock-like sample mold (1) further comprises a first baffle (17) and a second baffle (18) for closing the positioning long circular hole (13) on the first side mold (11) and the second side mold (12) to form a pouring cavity closed on the side, and the fine cotton thread (34) passes through the middle of the first baffle (17) and the second baffle (18).

3. A mold for making a rock-like material containing an internal prefabricated crack according to claim 2, characterized in that, The rock-like sample mold (1) further comprises a fastening band (16) for fastening the top and bottom ends of the rock-like sample mold (1).

4. A mold for making a rock-like material containing an internal prefabricated crack according to claim 3, characterized in that, The contact parts of the first side mold (11) and the second side mold (12) are respectively designed with a concave-convex groove with a width and height of 1mm-5mm to ensure that the spliced parts are tightly sealed and do not leak grout.

5. A mold for making a rock-like material containing an internal prefabricated crack according to claim 4, characterized in that, The bottom mold (2) comprises a circular groove (21) for placing the first side mold (11) and the second side mold (12) of the rock-like sample mold (1).

6. A mold for making a rock-like material containing an internal prefabricated crack according to claim 5, characterized in that, The prefabricated crack mold (3) further comprises a thickness mark (35) arranged on the inner side wall of the water containing device (31) for determining the thickness of the prefabricated crack.

7. A mold for making a rock-like material containing an internal prefabricated crack according to claim 6, characterized in that, The prefabricated crack mold (3) further comprises a crack baffle (36), and the water level in the water containing device (31) is adjusted by adjusting the opening of the crack baffle (36) according to the test requirements.

8. A mold for making a rock-like material containing an internal prefabricated crack according to claim 7, characterized by The rock-like sample mold (1) is a cylinder or a cuboid or a shape adjusted according to test requirements.

9. A mold for making a rock-like material containing an internal prefabricated crack according to claim 8, characterized in that, The shape of the prefabricated crack mold (3) is adjusted according to test requirements and matches the rock-like sample mold (1).

10. A method for making a rock-like material having internal preformed cracks, using a mold for making a rock-like material having internal preformed cracks as claimed in claim 9, characterized in that, It comprises the following steps: S100: preparing similar material of rock sample; S200: The prefabricated crack is made by using the prefabricated crack mold. First, the cotton thread is threaded through the threading platform, then the crack baffle is installed, then water is injected in the center of the prefabricated crack mold, the water level reaches the required thickness mark, and then the water injection is stopped. Put the whole prefabricated crack mold into the refrigerator for freezing, and after freezing, put the prefabricated crack mold into warm water for a few seconds, then take out the prefabricated crack together with the cotton thread, get the prefabricated crack, then put the prefabricated crack into the refrigerator for freezing, and use the same method to make different thickness prefabricated cracks for standby; S300: According to the number, angle and spacing of the prefabricated cracks, the angle height mark is determined by calculation, the positioning bolt is screwed into the positioning long circular hole for fixation on the first side mold according to the angle mark, then the positioning bolt is screwed into the positioning long circular hole and fixed at another position according to the height mark, then the cotton thread on the prefabricated crack is tied on the positioning bolt, and immediately install the first baffle and the second baffle on the first side mold, and the same operation is performed on the second side mold; While tying the cotton thread, slowly splice the first side mold and the second side mold along the slot, and place the spliced rock-like mold in the circular groove of the bottom mold and fasten it with the fastening belt to form a pouring cavity; S400: Pour similar materials into the cavity, and after vibration, curing and demolding, uniaxial and triaxial rock-like samples containing different numbers, angles and spacings of internal real prefabricated cracks can be obtained.

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