Preparation method and preparation device of soft and hard interbedded rock sample with dip angle

Abstract

The invention discloses a preparation method of a soft and hard interbed rock sample with an inclination angle, and relates to the technical field of soft and hard interbed rock mass samples. The pouring time interval of the soft rock and the hard rock is determined by comparing with the shear strength of the natural rock, the soft and hard interbed rock with the dip angle is prepared by adopting the soft and hard interbed rock preparation device, and the soft and hard interbed rock samples with different bedding dip angles and different layer thickness ratios can be prepared. The invention further discloses a device for preparing the soft and hard interbedded rock sample with the dip angle, and the device is used for implementing the preparation method.

Description

Technical Field

[0001] The invention relates to the technical field of soft and hard interbedded rock samples, and provides a method for preparing soft and hard interbedded rock samples with an inclination angle, and a preparation device for realizing the preparation method. Background Art

[0002] Interlayered rock mass refers to an interlayered geological structure composed of two or more groups of rock masses with large differences in lithology strength. It is a special type of rock mass often encountered in the construction of tunnels, coal mines and other projects, and is widely distributed in my country. Due to the presence of soft rock and interlayered structural surfaces in interlayered rock mass, its mechanical mechanism is complex. Therefore, it is very necessary to carry out mechanical research on interlayered rock mass, which is of great significance to the excavation of tunnels and lanes in interlayered rock mass.

[0003] Due to the complex morphology of natural soft and hard interlayered rocks and unclear boundaries of interlayered structural surfaces, some mechanical properties of soft and hard interlayered rock cannot be obtained through experiments; the cost of conducting on-site in-situ tests on soft and hard interlayered rock is too high, and the environment of soft and hard interlayered rock tunnels and lanes is complex, making it difficult to conduct on-site rock tests. Therefore, there is an urgent need for a method for preparing soft and hard interlayered rocks with different bedding inclinations, and a preparation device for implementing the preparation method, so that indoor tests on soft and hard interlayered rock can be carried out smoothly.

[0004] Therefore, in order to smoothly carry out a series of indoor tests on soft and hard interbedded rocks, a preparation device is needed that has a simple preparation method, does not require secondary processing, and can prepare soft and hard interbedded rock samples with different inclinations, so as to realize the preparation method of soft and hard interbedded rock samples with different inclinations and prepare soft and hard interbedded rocks with obvious boundaries of interbedded structural surfaces, clear morphology and good homogeneity. Summary of the invention

[0005] The first purpose of the present invention is to provide a method for preparing soft and hard interlayered rock samples with an inclination angle, which can quickly prepare soft and hard interlayered rocks with obvious interlayer structural surface boundaries, clear morphology and good homogeneity; the second purpose of the present invention is to provide a device for preparing soft and hard interlayered rock samples with an inclination angle to realize the above-mentioned preparation method.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] A method for preparing a soft-hard interbedded rock sample with an inclination angle comprises the following steps:

[0008] S1: Determine the mix ratio of soft rock and hard rock materials based on the mechanical properties of natural soft rock and hard rock;

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

[0010] S3: Prepare soft and hard interbedded rock samples with inclination angles using a soft and hard interbedded rock preparation device;

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

[0012] a base, arranged horizontally, for supporting the device;

[0013] The rotating base is connected to one end of the base and is arranged at an angle, and the angle is adjustable;

[0014] The mold frame is fixedly connected to the rotating base, and the transparent mold is detachably connected to the inside of the mold frame;

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

[0016] The step S3 specifically includes:

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

[0018] S32, adjusting the angle of the rotating base to the desired inclination angle, and vertically marking a number of scale lines on the transparent mold according to the set layer thickness, and then placing the transparent mold into the mold frame;

[0019] S33, pour the hard rock material to the first scale line, turn on the vibrator, and turn off the vibrator after the concrete is dense; after the optimal pouring interval time described in step S2, continue to pour the soft rock material layer to the second scale line, turn on the vibrator, and turn off the vibrator after the soft rock material is dense; then repeat the above operation,

[0020] S34, after both the soft rock material and the hard rock material are solidified, demoulding and curing are performed.

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

[0022] S11, select mudstone and sandstone standard samples, conduct mechanical property tests, and obtain their mechanical property parameters;

[0023] S12, making multiple groups of soft rock and hard rock specimens and obtaining their mechanical property parameters, comparing the mechanical parameters of the soft rock and hard rock specimens with those of mudstone and sandstone standard specimens, and obtaining the material mix ratio of the soft rock and hard rock specimens with the most similar mechanical property parameters as the material mix ratio of the soft rock and hard rock.

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

[0025]

[0026] The mix ratio of hard rock materials is:

[0027]

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

[0029] S21, a single-sided shear test is performed on natural rocks with stratification to obtain the shear strength of the stratification structure plane of the natural rock;

[0030] S22, preparing soft rock and hard rock materials according to the material mix ratio determined in step S1, and using the soft rock and hard rock to cast at least two groups of soft and hard interlayer rock samples, wherein the casting interval time of the soft rock and the hard rock in each group of samples is different;

[0031] S23, perform a single-sided shear test on the sample described in step S22 to obtain the shear strength of the bedding structure surface of the sample, compare it with the shear strength of the natural rock bedding structure surface described in step S21, and select the sample with the closest shear strength, and set the casting interval time of the sample to the optimal casting interval time.

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

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

[0034] S222, preparing multiple groups of soft and hard interlayer rock samples of soft rock and hard rock interlayers, wherein the pouring time intervals of the soft rock and the hard rock of the samples increase in an arithmetic progression, and the pouring method of the samples is as follows:

[0035] Pour the hard rock material into the transparent mould, turn on the vibrator when the transparent mould is half full, turn off the vibrator when the material is dense, wait until the hard rock material / soft rock material reaches the initial setting time, continue pouring the soft rock / hard rock material until the mould is full, then turn on the vibrator, and turn off the vibrator when the concrete is dense.

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

[0037] A device for preparing a sample of soft and hard interbedded rock with an inclination angle, used to implement the method for preparing a sample of soft and hard interbedded rock, comprising:

[0038] a base, arranged horizontally, for supporting the device;

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

[0040] The mold frame is fixedly connected to the rotating base, and the transparent mold is detachably connected to the inside of the mold frame;

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

[0042] According to a specific embodiment, the vibrator is located directly below the transparent mold when it is connected to the rotating base. The transparent mold is a hexahedral structure, including a mold box and an upper cover of separate design, flanges are provided on the two symmetrical sides of the top of the mold box, a slot matching the flange is provided on the upper cover, and bolts or screws are provided on the upper cover above the slot, and the bottom of the bolts or screws are crimped with the flange of the mold box. The rotating base adjusts the angle with the base by adjusting the knob, and the adjusting knob is provided with angle adjustment scale lines.

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

[0044] 1. Able to prepare soft and hard interlayer rock samples with different bedding dips and different layer thickness ratios: soft and hard interlayer rock samples with specified dips can be prepared by adjusting the adjustment knob, and soft and hard interlayer rock samples with different layer thickness ratios can be prepared by marking the position of the interlayer structural surface on the transparent mold.

[0045] 2. The optimal mix 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 realistically restore the mechanical properties of natural soft and hard interlayered rocks.

[0046] 3. Based on the experimental data of shear test on natural bedding structure surface, the mechanical properties of the soft and hard interlayer structure surface of natural soft and hard interlayered rocks can be restored most realistically.

[0047] 4. It can prepare soft and hard interlayered rock samples with low internal material porosity and homogeneous lithology at different bedding angles: When pouring soft and hard interlayered rock materials, vibrating with a vibrator can effectively reduce the internal porosity of the soft and hard interlayered rock samples and improve the homogeneity of the samples.

[0048] 5. It is capable of preparing soft and hard interlayered rock samples with different bedding inclinations at one time, and the preparation device is easy to disassemble and assemble and can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a structural schematic diagram of a device for preparing soft and hard interlayered rocks according to an embodiment;

[0050] Figure 2 It is a structural schematic diagram of a transparent mold of an embodiment;

[0051] 1. Base; 2. Rotating base; 3. Mold rack; 4. Transparent mold; 41. Mold box; 42. Upper cover; 5. Vibrator. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] S1: Determine the mix ratio of soft rock and hard rock materials based on the mechanical properties of natural soft rock and hard rock;

[0054] Before preparing soft and hard interlayered rocks with different bedding angles, determine the material mix ratio of soft rock and hard rock:

[0055] S11, select mudstone and sandstone standard samples, conduct mechanical property tests, and obtain their mechanical property parameters.

[0056] The mudstone and sandstone samples with a size of 100×100×100 mm were selected for uniaxial compression test. The loading speed was set to 50 N / s, and the samples were loaded to obtain the mechanical properties parameters of the mudstone and sandstone samples, such as uniaxial compressive strength, elastic modulus, cohesion, internal friction angle, etc., as the basis for determining the material mix 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, prepare multiple groups of soft rock and hard rock specimens and obtain their mechanical property parameters, compare the mechanical parameters of soft rock and hard rock specimens with those of mudstone and sandstone standard specimens, and obtain the material mix ratio of soft rock and hard rock specimens with the closest mechanical property parameters as the material mix ratio of soft rock and hard rock. Based on the mechanical properties of the sandstone and mudstone specimens obtained in the previous step, the material component contents of soft rock and hard rock are respectively adjusted, and five groups of soft rock and hard rock specimens are prepared respectively. The material mix ratio of soft rock is shown in Table 2, and the material mix ratio of hard rock is shown in Table 3. The size of the specimens is 100×100×100mm.

[0060] Table 2 Mixing ratio of soft rock materials

[0061]

[0062] Table 3 Hard rock material mix ratio

[0063]

[0064] After the above samples were cured for 28 days according to the standard, uniaxial compression tests were carried out on the soft rock and hard rock samples respectively. The loading speed was set to 50 N / s, and the samples were loaded to obtain the mechanical properties parameters of each soft rock and hard rock sample, uniaxial compressive strength, elastic modulus, Poisson's ratio, cohesion, internal friction angle and other data. The mechanical properties parameters of soft rock and 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 properties parameters of the specimens are compared with those of the standard specimens of soft rock and hard rock, that is, Table 4 is compared with Table 1 to determine the optimal material mix ratio of soft rock and hard rock, respectively. By comparing the mechanical properties of mudstone and sandstone, the material mix ratio of the fifth group of specimens is determined to be the set material mix ratio, as shown in Table 5.

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

[0069]

[0070] S2: Determine the pouring time interval between soft rock and hard rock based on the test data of natural bedding structure plane shear test;

[0071] S21, single-sided shear test is performed on natural rocks with stratification to obtain the shear strength of the natural stratification structure plane;

[0072] The mechanical properties of bedding planes have a significant impact on the mechanical properties of soft and hard interlayered rock masses. Considering the mechanical properties of bedding planes, single-sided shear tests were carried out on natural rocks containing bedding to obtain the shear strength of natural bedding planes.

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

[0074] Taking the soft and hard interlayer rock sample with the size of 100mm*100mm*100mm, the soft rock thickness of 50mm and the hard rock thickness of 50mm as an example, the pouring steps of the soft and hard interlayer rock sample are as follows:

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

[0076] Use a mixer to prepare soft rock and hard rock materials respectively. Add a small amount of water to wet the cylinder wall of the mixer, gradually add soft rock or hard rock materials (except accelerator), add water at the same time, turn on the mixer, add water reducer after stirring for 1 to 3 minutes, continue stirring for the specified time, and add accelerator 0.5 minutes before the end of stirring. After the stirring is completed, the prepared soft rock and hard rock materials are taken out for use.

[0077] S222, preparing multiple groups of soft and hard interlayer rock samples with interlayers of soft rock and hard rock, wherein the pouring time intervals of the soft rock and the hard rock of the samples increase in an arithmetic progression;

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

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

[0080] Adjust the rotating knob to the 0° scale line to adjust the angle of the rotating base to 0°, mark the 50mm scale line on the outer wall of the transparent acrylic mold with an erasable pen, apply vaseline on the inner wall of the transparent acrylic mold, and place it in the mold frame.

[0081] Pour the hard rock material / soft rock into the mold until it reaches the 50mm mark, turn on the vibrator, and turn off the vibrator after the hard rock material is dense. 初 After that, continue pouring the soft rock / hard rock material. After the mold is full, turn on the vibrator. After the concrete is dense, turn off the vibrator. In this embodiment, the time increment is set to 1h. Repeat the above steps and set the pouring interval time 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 specimens are prepared. After preparation, the specimens are cured according to GB / T 50081-2002 standard.

[0082] S23, perform a single-sided shear test on the sample described in step S22 to obtain the shear strength of the bedding structure surface of the sample, compare it with the shear strength of the natural rock bedding structure surface described in step S21, and select the sample with the closest shear strength, and set the casting interval time of the sample to the optimal casting interval time.

[0083] The above-mentioned samples are cured for 28 days according to the standard, and then each sample is subjected to a single-sided shear test to obtain the shear strength of the bedding structure surface of each sample, and compared with the shear strength of the natural rock bedding structure surface described in step S21, respectively, to obtain and select the sample with the closest shear strength and mark it, then record the casting interval time of the sample, and set the casting interval time of the sample as the optimal casting interval time.

[0084] S3: Use the soft and hard interbedded rock preparation device to prepare soft and hard interbedded rock samples with inclination

[0085] In order to realize the preparation method of the present invention, a soft and hard interlayer rock preparation device with an inclination angle is designed. The specific structure is shown in Figure 1 As shown, Figure 1 It is a schematic structural diagram of a device for preparing soft and hard interlayered rocks according to an embodiment.

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

[0087] A base 1, arranged horizontally, for supporting the device;

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

[0089] The mold frame 3 is fixedly connected to the rotating base 2, and a transparent mold 4 is detachably connected to the inside thereof;

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

[0091] After the soft and hard interlayer rock preparation device is completed, and the mix ratio of the soft and hard rock layers and the pouring time interval are determined, the following will take the preparation of mudstone and sandstone interlayer rocks with an inclination angle of 45 and a soft rock layer thickness of 10mm and a hard rock layer thickness as an example:

[0092] S31, firstly, prepare soft rock and hard rock materials according to the operation of step S221.

[0093] S32, adjusting the angle of the rotating base to be 45° with the base, marking horizontal scale lines on the transparent mold at intervals of 10 mm in the vertical direction according to the layer thickness of 10 mm, and then placing the transparent mold into the mold frame;

[0094] First, adjust the knob and rotate it to the 45° scale line until the angle of the rotating base is adjusted to 45°; then, use an erasable pen to mark horizontal scale lines on the outer wall of the transparent mold at intervals of 10 mm in the vertical direction; finally, smear Vaseline on the transparent mold and place it in the mold frame.

[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 dense; after the optimal pouring interval time described in step S23, continue to pour 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 dense; repeat the above steps for subsequent pouring work.

[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 lower side in a plug-in manner to prevent the soft rock or hard rock material from leaking out of the mold box. Repeat the above operation until the pouring work is completed.

[0097] S34, the transparent acrylic mold is taken out and demoulding is performed after the concrete solidifies. After curing for 28 days under standard environment, the rock with 45° bedding inclination and 10 mm thick soft and hard interlayers is prepared.

[0098] According to a specific embodiment, see Figure 1 As shown, the vibrator 5 is located directly below the transparent mold 4 when it is connected to the rotating base 2.

[0099] See also Figure 2 As shown, the transparent mold 4 is a hexahedral structure, including a mold box 41 and an upper cover 42 of separate design, flanges are provided on the two symmetrical sides of the top of the mold box 41, and a slot matching the flanges is provided on the upper cover 42. Bolts or screws are provided on the upper cover 42 above the slots, and the bottom of the bolts or screws is crimped with the flanges of the mold box 41. Specifically, the acrylic plates constituting the mold box are assembled by assembling.

[0100] The rotating base 2 is adjusted to an angle with the base 1 by adjusting a knob, and the adjusting knob is provided with an angle adjustment scale line. Specifically, the rotating base and the base are driven by a gear mechanism or a gear train to achieve angle adjustment.

Claims

1. A method for preparing a sample of soft and hard interbedded rock with an inclination angle, characterized in that: The following steps are involved: S1: Determine the mix ratio of soft rock and hard rock materials based on the mechanical properties of natural soft rock and hard rock; S2: Determine the pouring time interval between soft rock and hard rock based on the test data of natural bedding structure plane shear test; S3: Prepare soft and hard interbedded rock samples with inclination angles using a soft and hard interbedded rock preparation device; The soft and hard interbedded rock preparation device comprises: A base (1) is arranged horizontally and is used to support the device; The rotating base (2) is connected to one end of the base (1) and is arranged at an angle, and the angle is adjustable; A mold frame (3) is fixedly connected to the rotating base (2), and a transparent mold (4) is detachably connected to the inside of the mold frame; A vibrator (5) is fixedly connected to the bottom of the rotating base (2); The step S3 specifically includes: S31, preparing soft rock and hard rock materials according to the mix ratio of soft rock and hard rock materials determined in step S1; S32, adjusting the angle of the rotating base to the desired inclination angle, and vertically marking a number of scale lines on the transparent mold according to the set layer thickness, and then placing the transparent mold into the mold frame; S33, pouring the hard rock material to the first scale line, turning on the vibrator (5), and turning off the vibrator (5) after the concrete is dense; after the optimal pouring interval time described in step S2, continue pouring the soft rock material layer to the second scale line, turning on the vibrator (5), and turning off the vibrator (5) after the soft rock material is dense; then repeat the above operation, S34, after both the soft rock material and the hard rock material are solidified, demoulding and curing are performed.

2. The method according to claim 1, characterized in that The specific operation of determining the mix ratio of soft rock and hard rock materials in step S1 is as follows: S11, select mudstone and sandstone standard samples, conduct mechanical property tests, and obtain their mechanical property parameters; S12, making multiple groups of soft rock and hard rock specimens and obtaining their mechanical property parameters, comparing the mechanical parameters of the soft rock and hard rock specimens with those of mudstone and sandstone standard specimens, and obtaining the material mix ratio of the soft rock and hard rock specimens with the most similar mechanical property parameters as the material mix 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 mix ratio of soft rock is: The mix ratio of hard rock materials is:

4. The method according to claim 1, characterized in that The step S2 of determining the pouring time interval of soft rock and hard rock is implemented by the following specific operations: S21, a single-sided shear test is performed on natural rocks with stratification to obtain the shear strength of the stratification structure plane of the natural rock; S22, preparing soft rock and hard rock materials according to the material mix ratio determined in step S1, and using the soft rock and hard rock to cast at least two groups of soft and hard interlayer rock samples, wherein the casting interval time of the soft rock and the hard rock in each group of samples is different; S23, perform a single-sided shear test on the sample described in step S22 to obtain the shear strength of the bedding structure surface of the sample, compare it with the shear strength of the natural rock bedding structure surface described in step S21, and select the sample with the closest shear strength, and set the casting interval time of the sample to the optimal casting interval time.

5. The method according to claim 4, characterized in that The specific operation of pouring the soft and hard interbedded rock sample in step S22 is as follows: S221, preparing soft rock and hard rock materials according to the material mix ratio determined in step S1; S222, preparing multiple groups of soft and hard interlayer rock samples of soft rock and hard rock interlayers, wherein the pouring time intervals of the soft rock and the hard rock of the samples increase in an arithmetic progression, and the pouring method of the samples is as follows: Pour the hard rock material into the transparent mould, turn on the vibrator when the transparent mould is half full, turn off the vibrator when the material is dense, wait until the hard rock material / soft rock material reaches the initial setting time, continue pouring the soft rock / hard rock material until the mould is full, then turn on the vibrator, and turn off the vibrator when the concrete is dense.

6. The method according to claim 1, characterized in that The angle of the rotating base (2) can be adjusted arbitrarily within the range of 0°-90°.

7. A device for preparing a sample of soft and hard interbedded rocks with an inclination angle, characterized in that: The method for preparing a soft-hard interbedded rock sample according to any one of claims 1 to 6 comprises: A base (1) is arranged horizontally and is used to support the device; The rotating base (2) is connected to one end of the base (1) and is arranged at an angle, and the angle is adjustable; A mold frame (3) is fixedly connected to the rotating base (2), and a transparent mold (4) is detachably connected to the inside of the mold frame; The vibrator (5) is fixedly connected to the bottom of the rotating base (2).

8. The method according to claim 7, characterized in that The vibrator (5) is located directly below the transparent mold (4) when it is connected to the rotating base (2).

9. The method according to claim 7, characterized in that: The transparent mold (4) is a hexahedral structure, comprising a mold box (41) and an upper cover (42) of separate design, wherein flanges are provided on two symmetrical sides of the top of the mold box (41), and a slot matching the flanges is provided on the upper cover (42), and bolts or screws are provided on the upper cover (42) above the slots, and the bottom of the bolts or screws is crimped with the flanges of the mold box (41).

10. The method according to claim 7, characterized in that The rotating base (2) is adjusted in angle with the base (1) by means of an adjustment knob, and the adjustment knob is provided with angle adjustment scale lines.

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