A method and device for preparing a soft and hard interbedded rock sample with an inclination angle

Abstract

The application discloses a preparation method of soft and hard interbedded rock samples with an inclination angle, relates to the technical field of soft and hard interbedded rock samples, and is characterized in that the material mixing ratio of hard rock and soft rock which is the closest to the mechanical property of natural rock is determined by a mechanical property testing method, the pouring time interval of the soft rock and the hard rock is determined by comparison with the shear strength of the natural rock, the soft and hard interbedded rock with the inclination angle is prepared by using a soft and hard interbedded rock preparation device, and the soft and hard interbedded rock samples with different bedding inclination angles and different layer thickness ratios can be prepared. The application further discloses a preparation device of the soft and hard interbedded rock samples with the inclination angle, which is used for realizing the preparation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soft and hard interbedded rock sample, a soft and hard interbedded rock sample preparation method with an inclination angle and a preparation device for realizing the preparation method. BACKGROUND

[0002] Soft and hard interbedded rock mass refers to an interbedded geological structure composed of two or more groups of rock mass with large differences in strength, which is a special rock mass often encountered in the process of tunnel, coal mine and other engineering construction, and is widely distributed in China. Due to the existence of soft rock and interbedded structure surface in soft and hard interbedded rock mass, the mechanical mechanism is complex. Therefore, it is necessary to carry out mechanical research on soft and hard interbedded rock mass, which is of great significance to the excavation of soft and hard interbedded rock mass tunnel and roadway.

[0003] Due to the complex appearance state of natural soft and hard interbedded rock, the interbedded structure surface is not clear, and some mechanical properties of soft and hard interbedded rock mass cannot be obtained by test; the cost of in-situ test on soft and hard interbedded rock mass is too high, and the environment of soft and hard interbedded rock mass tunnel and roadway is complex, so it is difficult to carry out in-situ rock mass test. Therefore, a soft and hard interbedded rock preparation method with different bedding angles and a preparation device for realizing the preparation method are needed, so that the indoor test of soft and hard interbedded rock mass can be carried out smoothly.

[0004] Therefore, in order to smoothly carry out a series of indoor tests of soft and hard interbedded rock, a preparation device with simple preparation method, no secondary processing and ability to prepare soft and hard interbedded rock sample with different inclination angles is needed, so as to realize the preparation method of soft and hard interbedded rock sample with different inclination angles, and prepare soft and hard interbedded rock with clear interbedded structure surface boundary, clear appearance state and good homogeneity. SUMMARY

[0005] The first object of the present application is to provide a soft and hard interbedded rock sample preparation method with an inclination angle, which can quickly prepare soft and hard interbedded rock with clear interbedded structure surface boundary, clear appearance state and good homogeneity; the second object of the present application is to provide a soft and hard interbedded rock sample preparation device with an inclination angle to realize the above preparation method.

[0006] The technical solution for realizing the object of the present application is:

[0007] A soft and hard interbedded rock sample preparation method with an inclination angle, comprising the following steps:

[0008] S1: determining the mixing ratio of soft rock and hard rock based on the mechanical properties of natural soft rock and hard rock;

[0009] S2: determining the pouring time interval of soft rock and hard rock based on the test data of natural bedding structure surface shear test;

[0010] S3: using a soft and hard interbedded rock preparation device to prepare a soft and hard interbedded rock sample with an inclination angle;

[0011] The soft and hard interbeded rock preparation device comprises:

[0012] a base horizontally arranged to support the device;

[0013] a rotating base connected to one end of the base at an angle and adjustable in angle;

[0014] a mold frame fixedly connected to the rotating base and having a transparent mold detachably connected inside;

[0015] a vibrator fixedly connected to the bottom of the rotating base;

[0016] The step S3 specifically comprises:

[0017] S31: preparing soft rock and hard rock materials according to the mixing ratio of the soft rock and hard rock materials determined in step S1;

[0018] S32: adjusting the angle of the rotating base to the inclination angle required to be prepared, marking a plurality of scale lines vertically on the transparent mold according to the set bedding thickness, and then placing the transparent mold into the mold frame;

[0019] S33: pouring the hard rock material to the first scale line, turning on the vibrator, and turning off the vibrator after the concrete is compacted; after the interval of the optimal pouring interval time in step S2, continuously pouring the soft rock material layer to the second scale line, turning on the vibrator, and turning off the vibrator after the soft rock material is compacted; then repeating the above operation,

[0020] S34: performing demolding and curing treatment after the soft rock material and the hard rock material are both solidified.

[0021] The specific operation of determining the mixing ratio of the soft rock and hard rock materials in step S1 is as follows:

[0022] S11: selecting mudstone and sandstone standard samples to perform a mechanical property test to obtain the mechanical property parameters thereof;

[0023] S12: preparing a plurality of groups of soft rock and hard rock samples to obtain the mechanical property parameters thereof, comparing the mechanical parameters of the soft rock and hard rock samples with those of the mudstone and sandstone standard samples, and obtaining the material mixing ratio of the soft rock and hard rock samples with the closest mechanical property parameters as the material mixing ratio of the soft rock and hard rock materials.

[0024] In step S1, the material mixing ratio of the soft rock is:

[0025]

[0026] The material mixing ratio of the hard rock is:

[0027]

[0028] The step S2 of determining the pouring interval of soft rock and hard rock is realized by the following specific operation:

[0029] S21, a single shear test is performed on the natural rock with bedding to obtain the shear strength of the bedding structure surface of the natural rock;

[0030] S22, the soft rock and hard rock materials are prepared according to the material mixing ratio determined in step S1, and at least two groups of soft-hard interbedded rock samples are poured with the soft rock and the hard rock, and the pouring interval time of the soft rock and the hard rock in each group of samples is different;

[0031] S23, a single shear test is performed on the sample in step S22 to obtain the shear strength of the bedding structure surface of the sample, which is compared with the shear strength of the bedding structure surface of the natural rock in step S21, and the sample with the most similar shear strength is selected, and the pouring interval time of the sample is set as the optimal pouring interval time.

[0032] The specific operation of pouring the soft-hard interbedded rock sample in step S22 is as follows:

[0033] S221, the soft rock and hard rock materials are prepared according to the material mixing ratio determined in step S1;

[0034] S222, a plurality of groups of soft-hard interbedded rock samples are prepared, wherein the pouring interval time of the soft rock and the hard rock of the sample is in an arithmetic progression, and the pouring method of the sample is as follows:

[0035] The hard rock material is poured into the transparent mold, the vibrator is started after the transparent mold is filled to half, the vibrator is turned off after the material is compacted, and the soft rock / hard rock material is continuously poured after the initial setting time of the hard rock material / soft rock material is reached, and the vibrator is turned off after the concrete is compacted.

[0036] In order to realize the preparation of soft-hard interbedded rock with different bedding angles, the angle of the rotating base can be adjusted within the range of 0°-90°.

[0037] A soft-hard interbedded rock sample preparation device with an angle, for realizing the soft-hard interbedded rock sample preparation method, comprising:

[0038] A base is horizontally arranged to support the device;

[0039] A rotating base is connected to one end of the base at an angle and the angle is adjustable;

[0040] A mold holder is fixedly connected to the rotating base, and a transparent mold is detachably connected inside the mold holder;

[0041] A vibrator is fixedly connected to the bottom of the rotating base.

[0042] According to one specific embodiment, the vibrator is located directly below the transparent mold when the transparent mold is connected to the rotating base. The transparent mold is a hexahedral structure including a mold box and an upper cover in a split design, the top of the mold box is provided with two symmetrical side edges with flanges, the upper cover is provided with a slot matched with the flanges, and a bolt or screw is arranged on the upper cover above the slot, and the bottom of the bolt or screw is press-connected with the flanges of the mold box. The rotating base adjusts the angle with the base through an adjusting knob, and the adjusting knob is provided with an angle adjusting scale line.

[0043] The present application has the following technical effects:

[0044] 1. Soft and hard interbedded rock samples with different interbedding angles and different layer thickness ratios can be prepared: soft and hard interbedded rock samples with specified angles can be prepared by adjusting the adjusting knob, and soft and hard interbedded rock samples with different layer thickness ratios can be prepared by marking the interbedding structure surface position on the transparent mold.

[0045] 2. The optimal mixing ratio of soft rock and hard rock materials is determined based on the mechanical properties of natural soft rock and hard rock, which can most truly restore the mechanical properties of natural soft and hard interbedded rock.

[0046] 3. Based on the test data of natural interbedding structure surface shear test, the mechanical properties of the soft and hard interbedded structure surface of the natural soft and hard interbedded rock can be most truly restored.

[0047] 4. Soft and hard interbedded rock samples with different interbedding angles and homogeneous lithology can be prepared: when pouring the soft and hard interbedded rock material, the internal porosity of the soft and hard interbedded rock sample can be effectively reduced and the homogeneity of the sample can be improved by the vibrator.

[0048] 5. Soft and hard interbedded rock samples with different interbedding angles can be prepared at one time, and the preparation device is easy to disassemble and reassemble, and can be reused. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The structure diagram of the soft and hard interbedded rock preparation device of the embodiment;

[0050] Figure 2 The structure diagram of the transparent mold of the embodiment;

[0051] 1, base; 2, rotating base; 3, mold frame; 4, transparent mold; 41, mold box; 42, upper cover; 5, vibrator. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work are within the protection scope of the present application.

[0053] S1: determining the material mixing ratio of soft rock and hard rock based on the mechanical properties of natural soft rock and hard rock;

[0054] Before preparing the soft-hard interbedded rock with different bedding angles, the material mixing ratio of soft rock and hard rock is determined:

[0055] S11: selecting mudstone and sandstone standard samples to perform mechanical property tests and obtain the mechanical property parameters thereof.

[0056] Selecting 100*100*100mm mudstone and sandstone samples to perform uniaxial compression tests, setting the loading speed as 50N / s, loading the samples, and obtaining the mechanical property parameters of the mudstone and sandstone samples, such as uniaxial compressive strength, elastic modulus, cohesion, internal friction angle and other data, as the basis for determining the material mixing ratio. The mechanical properties of mudstone and sandstone are shown in Table 1.

[0057] Table 1: Mechanical properties of mudstone and sandstone

[0058]

[0059] S12: making multiple groups of soft rock and hard rock samples and obtaining the mechanical property parameters thereof, comparing the mechanical parameters of the soft rock and hard rock samples with those of the mudstone and sandstone standard samples, and obtaining the material mixing ratio of the soft rock and hard rock samples with the closest mechanical property parameters as the material mixing ratio of soft rock and hard rock. Based on the mechanical properties of the sandstone and mudstone samples obtained in the previous step, the material component content of soft rock and hard rock is adjusted, and five groups of soft rock and hard rock samples are respectively made, wherein the material mixing ratio of soft rock is shown in Table 2, and the material mixing ratio of hard rock is shown in Table 3. The size of the samples is 100*100*100mm.

[0060] Table 2: Material mixing ratio of soft rock

[0061]

[0062] Table 3: Material mixing ratio of hard rock

[0063]

[0064] After the above samples are cured for 28 days according to the standard, uniaxial compression tests are respectively performed on the soft rock and hard rock samples, a loading speed of 50 N / s is set, the samples are loaded, and the mechanical property parameters of each sample of the soft rock and the hard rock, uniaxial compressive strength, elastic modulus, Poisson's ratio, cohesive force, internal friction angle and other data are obtained, wherein the mechanical property parameters of the soft rock and the hard rock are shown in Table 4.

[0065] Table 4 Mechanical properties of soft rock and hard rock

[0066]

[0067] Based on the similarity theory, the mechanical property parameters of the test piece and the standard sample of the soft rock and the hard rock are compared, that is, Table 4 is compared with Table 1, the optimal material mix ratio of the soft rock and the hard rock is determined respectively, and the material mix ratio of the fifth group of test pieces is determined as the set material mix ratio by comparing the mechanical properties of the mudstone and the sandstone, see Table 5 for details.

[0068] Table 5 Optimal material mix ratio of soft rock and hard rock

[0069]

[0070] S2: The pouring time interval of the soft rock and the hard rock is determined based on the test data of the natural bedding structure surface shear test;

[0071] S21, a single shear test is performed on the natural rock containing bedding, and the shear strength of the natural bedding structure surface is obtained;

[0072] The mechanical properties of the bedding structure surface have a significant influence on the mechanical properties of the soft and hard interbedded rock mass, and the mechanical properties of the bedding structure surface are considered, a single shear test is performed on the natural rock containing bedding, and the shear strength of the natural bedding structure surface is obtained.

[0073] S22, the soft rock and hard rock materials are prepared according to the material mix ratio determined in step S1, and at least two groups of soft and hard interbedded rock samples are prepared using the soft rock and hard rock materials;

[0074] A soft and hard interbedded rock sample with a size of 100mm*100mm*100mm, a soft rock thickness of 50mm and a hard rock thickness of 50mm is taken as an example for introduction, and the pouring steps of the soft and hard interbedded rock sample are as follows:

[0075] S221, the soft rock and hard rock materials are prepared according to the material mix ratio determined in step S1, and the material mix ratio of the soft rock and the hard rock is shown in Table 5.

[0076] The soft rock and hard rock materials are respectively prepared by a mixer. A small amount of water is added to wet the cylinder wall. The soft rock or hard rock material (except for the accelerator) is gradually added, and water is added at the same time. The mixer is started. After 1-3 minutes of stirring, the water reducing agent is added, and the stirring is continued until the specified time. The accelerator is added 0.5 minutes before the end of the stirring. After the stirring is completed, the prepared soft rock and hard rock materials are poured out for standby.

[0077] S222, a plurality of soft rock and hard rock interbedded soft and hard interbedded rock samples are prepared, wherein the pouring time intervals of the soft rock and the hard rock of the sample form an arithmetic sequence increasing;

[0078] In this embodiment, n+1 groups of soft and hard interbedded rock samples are prepared, wherein the pouring time intervals T n of the soft rock and the hard rock of the sample 初 +(n-1)t, n∈N, wherein T 初 represents the initial setting time of the hard rock, and t represents the time increment; in this embodiment, T 初 is about 1 hour, and the time increment t can be arbitrarily set, such as 1 h, 30 min, 50 min, etc. The pouring method of the sample is as follows:

[0079] As shown in Figure 2 , the mold box of the transparent mold is a cube with an inner length, width and height of 100 mm, which is assembled by transparent acrylic plates.

[0080] By adjusting the rotating knob to the 0° scale line, the rotating base angle is adjusted to 0°. A 50 mm scale line is marked on the outer wall of the transparent acrylic mold with a erasable pen. After the inner wall of the transparent acrylic mold is smeared with vaseline, it is placed in the mold frame.

[0081] The hard rock material / soft rock is poured into the mold to the 50 mm scale line. After the hard rock material is compacted, the vibrator is turned off. After the concrete reaches the initial setting time H 初 , the soft rock / hard rock material is continuously poured. After the mold is full, the vibrator is turned on. After the concrete is compacted, the vibrator is turned off. In this embodiment, the time increment is set to 1 h. The above steps are repeated, and the pouring interval time is set to H 初 +1 hour, H 初 +2 hours, H 初 +3 hours, H 初 +4 hours, H 初 +5 hours, …, H 初 +n hours, a total of n+1 groups of samples are prepared. After the preparation is completed, the sample is cured according to the GB / T 50081-2002 standard.

[0082] S23, a single shear test is performed on the sample described in step S22 to obtain the shear strength of the stratification structure surface of the sample, which is compared with the shear strength of the stratification structure surface of the natural rock described in step S21, and the sample with the shear strength closest to the shear strength of the natural rock is selected, and the pouring interval time of the sample is set as the optimal pouring interval time.

[0083] The above sample is standard cured for 28 days, and then a single shear test is performed on each sample to obtain the shear strength of the stratification structure surface of each sample, which is compared with the shear strength of the stratification structure surface of the natural rock described in step S21, and the sample with the shear strength closest to the shear strength of the natural rock is selected and marked, and then the pouring interval time of the sample is recorded, and the pouring interval time of the sample is set as the optimal pouring interval time.

[0084] S3: A soft and hard interbedded rock sample with an inclination angle is prepared by using a soft and hard interbedded rock preparation device

[0085] In order to realize the preparation method of the present application, a soft and hard interbedded rock preparation device with an inclination angle is designed, and the specific structure is shown in Figure 1 Figure 1 The structure diagram of the soft and hard interbedded rock preparation device of the embodiment.

[0086] The soft and hard interbedded rock preparation device comprises:

[0087] The base 1 is horizontally arranged and used for supporting the device;

[0088] The rotating base 2 is connected with one end of the base 1 and arranged at an angle, and the angle is adjustable;

[0089] The mold frame 3 is fixedly connected on the rotating base 2, and the transparent mold 4 is detachably connected in the mold frame 3;

[0090] The vibrator 5 is fixedly connected at the bottom of the rotating base 2.

[0091] After the soft and hard interbedded rock preparation device is manufactured, and the mixing ratio and pouring interval time of the soft and hard rock layers are determined, the following will take the interbedded rock of mudstone and sandstone with an inclination angle of 45° and a soft rock layer thickness and a hard rock layer thickness of 10mm as an example for introduction:

[0092] S31, first, the soft rock and hard rock materials are prepared according to the operation of step S221.

[0093] S32, the angle of the rotating base is adjusted to 45° with the base, and the horizontal scale line is marked on the transparent mold at an interval of 10mm along the vertical direction at an interval of 10mm, and then the mold frame is put into the mold frame;

[0094] ​First, the knob is rotated to the 45° scale line, and the rotating base is adjusted to 45°. Then, the transparent mold outer wall is marked with a horizontal scale line at an interval of 10 mm in the vertical direction using an erasable pen. Finally, the transparent mold is placed in the mold frame after being smeared with Vaseline.

[0095] S33, pour the hard rock / soft rock material to the first scale line, turn on the vibrator, and turn off the vibrator after the concrete is compacted. After the optimal pouring interval time described in step S23, continue pouring the soft rock / hard rock material to the second scale line, turn on the vibrator, and turn off the vibrator after the soft rock material is compacted. The pouring work is repeated as described above.

[0096] When the soft rock or hard rock material is poured to the opening of the transparent mold, the upper cover is installed on the mold box from the low side in a plug-in manner to prevent the soft rock or hard rock material from leaking out of the mold box. The above operation is repeated until the pouring work is completed.

[0097] S34, the transparent acrylic mold is removed, and the concrete is demolded after solidification. After 28 days of curing in a standard environment, the 45°-angled rock with soft and hard interbedding of 10 mm thick is prepared.

[0098] According to one specific embodiment, referring to Figure 1 The vibrator 5 is located directly below the transparent mold 4 when it is connected to the rotating base 2.

[0099] Referring to Figure 2 The transparent mold 4 is a hexahedral structure, including a mold box 41 and an upper cover 42 designed in two parts. The top of the mold box 41 is provided with two symmetrical side edges with flanges. The upper cover 42 is provided with a slot matched with the flanges. The upper cover 42 above the slot is provided with a bolt or screw. The bottom of the bolt or screw is in pressure contact with the flanges of the mold box 41. Specifically, the acrylic plates constituting the mold box are assembled by splicing.

[0100] The rotating base 2 adjusts the angle with the base 1 through an adjusting knob, which is provided with an angle adjustment scale line. Specifically, the rotating base and the base are adjusted in angle through a gear mechanism or a wheel train transmission.

Claims

1. A method for preparing a soft-hard interbedded rock sample with an inclination angle, characterized in that, The method comprises the following steps: S1: determining the material mixing ratio of soft rock and hard rock based on the mechanical properties of natural soft rock and hard rock; S2: determining the pouring interval of soft rock and hard rock based on the test data of natural bedding structural plane shear test; S21, single-surface shear test is performed on the natural rock containing bedding, and the shear strength of the natural rock bedding structure plane is obtained; S22, soft rock and hard rock materials are prepared according to the material mixing ratio determined in step S1, and at least two groups of soft-hard interbedded rock samples are poured with the soft rock and hard rock, and the pouring interval time of the soft rock and hard rock in each group of samples is different; S23, single-surface shear test is performed on the sample in step S22, the shear strength of the bedding structure plane of the sample is obtained, and the shear strength is compared with the shear strength of the natural rock bedding structure plane in step S21, and the sample with the most similar shear strength is selected, and the pouring interval time of the sample is set as the optimal pouring interval time; S3: preparing a soft-hard interbedded rock sample with an inclination angle by using a soft-hard interbedded rock preparation device; The soft-hard interbedded rock preparation device comprises: a base (1) horizontally arranged for supporting the device; a rotating base (2) connected with one end of the base (1) and arranged at an angle, and the angle is adjustable, the rotating base (2) adjusts the angle with the base (1) by adjusting a knob, and the knob is provided with an angle adjustment scale line; a mold frame (3) fixedly connected with the rotating base (2), and a transparent mold (4) is detachably connected in the mold frame (3); a vibrator (5) fixedly connected with the bottom of the rotating base (2); The step S3 specifically comprises: S31, preparing soft rock and hard rock materials according to the material mixing ratio of soft rock and hard rock determined in step S1; S32, adjusting the angle of the rotating base to the inclination angle required for preparation by rotating the adjusting knob, and vertically marking a plurality of scale lines on the transparent mold according to the set bedding thickness, and then placing the transparent mold into the mold frame; S33, pouring the hard rock material to the first scale line, starting the vibrator (5), and closing the vibrator (5) after the concrete is compacted; after the optimal pouring interval time in step S2, continue to pour the soft rock material layer to the second scale line, start the vibrator (5), and close the vibrator (5) after the soft rock material is compacted, and then repeat the above operation until all rock layers are poured; S34, taking out the transparent acrylic mold, and performing demolding and curing treatment after the soft rock material and the hard rock material are solidified.

2. The method of claim 1, wherein, The specific operation of determining the material mixing ratio of soft rock and hard rock in step S1 is as follows: S11, selecting mudstone and sandstone standard samples to perform mechanical property test and obtain the mechanical property parameters; S12, preparing a plurality of soft rock and hard rock samples and obtaining the mechanical property parameters, comparing the mechanical parameters of the soft rock and hard rock samples with the mechanical parameters of the mudstone and sandstone standard samples, and obtaining the material mixing ratio of the soft rock and hard rock samples with the most similar mechanical property parameters as the material mixing ratio of the soft rock and hard rock.

3. The method according to claim 1 or 2, characterized in that, In step S1, the material mixing ratio of the soft rock is: The material mixing ratio of the hard rock is: 。 4. The method of claim 1, wherein, The specific operation of pouring the soft-hard interbedded rock sample in step S22 is as follows: S221, preparing soft rock and hard rock materials according to the material mixing ratio determined in step S1; S222, a plurality of soft rock, hard rock interbedded soft and hard interbedded rock sample is prepared, wherein the interval between the pouring time of the soft rock and the hard rock of the sample is an arithmetic sequence increasing, and the pouring method of the sample is as follows: The hard rock material is poured into the transparent mold, the vibrator is started after half of the capacity of the transparent mold, the vibrator is closed after the material is compacted, and after the hard rock material / soft rock material reaches the initial setting time, the soft rock / hard rock material is continuously poured until the mold is full, and then the vibrator is closed after the concrete is compacted.

5. The method of claim 1, wherein, The angle of the rotating base (2) is adjusted within the range of 0-90 degrees.

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