Nonlinear seepage velocity testing device and method for rock mass with through cracks

Abstract

The present invention belongs to the field of experimental research on rock seepage, and provides a device and method for testing the non-linear seepage flow velocity of a rock mass with a through crack. The device includes: a water supply part, a piezometric part, a water seepage part, a pore matrix part, a through crack, and a drainage part; the output end of the water supply part is connected to the water seepage part, the water seepage part is connected to the piezometric part and the pore matrix part, and the pore matrix part is filled with a pore matrix; the pore matrix is located on both sides of the through crack, and the through crack is a hollow structure or partially filled; the drainage part includes a number of drainage chambers arranged side by side, and the pore matrix and the through crack are respectively connected to corresponding drainage chambers; the present invention can effectively measure the change of the flow velocity of the rock mass with a through crack at the through crack, can calculate the seepage flow rate with a through crack more accurately, and proposes the variation law of the non-linear seepage flow velocity.

Description

Technical Field

[0001] The present invention belongs to the field of experimental research on rock seepage, and particularly relates to a device and method for testing the non-linear seepage velocity of a rock mass with a through crack. Background Art

[0002] The through and non-through cracks, pipes and pore structures in soil together constitute a complex porous network system. Among them, the through pipe cracks are the main paths for the mutual conversion of groundwater and surface water, an important channel for the hydraulic connection between groundwater and rock and soil masses, and also the boundary conditions often traced by the instability and failure of rock and soil masses.

[0003] Since the microscopic structures of the cracks and pores that make up the porous medium are extremely complex and irregular, in the study of seepage problems, statistical methods are usually adopted macroscopically, that is, mainly studying the average velocity and pressure of fluid flow on the seepage cross-section (the formation cross-section perpendicular to the fluid flow direction), rather than studying the flow conditions in individual cracks and pores.

[0004] Currently, the seepage velocity test mainly measures the velocity of a fixed cross-section, and there is no discussion on exploring the change in seepage velocity with the distance from the through crack. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a device and method for testing the non-linear seepage velocity of a rock mass with a through crack to solve the problems in the prior art. The technical solution adopted by the present invention is as follows:

[0006] A device for testing the non-linear seepage velocity of a rock mass with a through crack includes: a water supply part, a piezometric part, a water seepage part, a pore matrix part, a through crack, and a drainage part;

[0007] The output end of the water supply part is connected to the water seepage part, the water seepage part is connected to the piezometric part and the pore matrix part, and the pore matrix part is filled with pore matrix; the pore matrix is located on both sides of the through crack, and the through crack is a hollow structure or partially filled;

[0008] The drainage part includes a plurality of drainage chambers arranged side by side, and the pore matrix and the through crack are respectively connected to the corresponding drainage chambers.

[0009] Further, the pore matrix part includes an independent box body, a side-through grid plate, and an end grid plate; the independent box body is filled with pore matrix.

[0010] The independent box bodies are divided into two groups, and a plurality of independent box bodies in each group are arranged side by side, and the two groups of independent box bodies are spaced apart to form the through crack;

[0011] The side of the independent box body is fixedly provided with the side through-grid plate, and the end grid plates are arranged at both ends of the independent box body. Both ends of the independent box body are respectively communicated with the water seepage part and the drainage part through the end grid plates; adjacent two independent box bodies are communicated through the side through-grid plate.

[0012] Further, the water seepage part includes a water inlet box body, the water inlet box body is communicated with the water supply part and the pressure measurement part, a water inlet opening is arranged on the side of the water inlet box body, and the water inlet opening is communicated with the end grid plate.

[0013] Further, the drainage part includes a drainage box body, a partition board and a drainage pipe;

[0014] A plurality of the partition boards are arranged in the drainage box body to divide the interior of the drainage box body into a plurality of drainage chambers. A drainage opening is arranged on the side of the drainage box body, and the drainage opening is communicated with the drainage chamber. The plurality of drainage chambers are respectively communicated with the end grid plate and the through crack through the drainage opening in one-to-one correspondence.

[0015] Further, the pressure measurement part includes a piezometer tube, a stop block, a slider, a spring and a piston;

[0016] The piezometer tube is arranged vertically, and its bottom is communicated with the water seepage part. The piston is arranged in the piezometer tube. The piston is of a hollow structure. The slider can slide through the inside of the piston. The top and bottom of the slider are both of a T-shaped structure. The spring is arranged below the T-shaped structure at the top of the slider. The spring is sleeved on the slider. The T-shaped structure at the bottom of the slider abuts against the bottom surface of the piston;

[0017] The slider is provided with a diversion hole with an upward opening, and a through hole communicating with the diversion hole is arranged on the side surface of the slider. The inner wall surface of the piston blocks the through hole. The stop block is arranged above the slider, and a pressure relief hole adapted to the diversion hole is arranged on the stop block;

[0018] When the piston rises until the slider abuts against the stop block, the slider moves downward, so that the through hole moves downward away from the piston, so that the through hole, the diversion hole and the pressure relief hole are communicated with the part of the piezometer tube below the piston;

[0019] The piezometer tube is provided with scale lines for pressure measurement.

[0020] A non-linear seepage flow velocity test method for a rock mass with a through crack includes the following steps:

[0021] Step 1, arrange the test device. The water supply part, the water seepage part, the pore matrix part and the drainage part are communicated in sequence. The water seepage part is communicated with the pressure measurement part. The pore matrix part is filled with pore matrix, and a through crack is arranged;

[0022] Step 2: The water supply part supplies water to the seepage part. The water pressure of the seepage part is observed through the piezometric part, and the water discharge of each drainage chamber is collected. The water volumes of each drainage chamber are successively recorded as V1 、 V2 、 V3 …… V n , and the average flow velocity of the drainage chamber is calculated through the flow rate, and the flow velocity distribution curve is drawn;

[0023] Step 3: After the test, the pore matrix is taken out, and according to the geotechnical test standard, the porosity n and permeability K of the converted pore matrix are measured. Through the measured K and n values and the characteristic dimensions of each part of the model, the flow velocity distribution of the pore matrix is calculated.

[0024] Furthermore, in Step 1, the through crack is a hollow structure or partially filled. When it is partially filled, a plate body is placed in the through crack, and a gap is formed between the plate body and the inner wall surface of the through crack. Particles are filled in this gap, and then the plate body is taken out to form a partially filled through crack.

[0025] Furthermore, in Step 3, the porosity n and permeability K are obtained by the following formula:

[0026] ,

[0027] In the formula: Q is the water volume flowing through the pore matrix part;

[0028] L is the length of the pore matrix;

[0029] A is the cross-sectional area of the pore matrix;

[0030] is the head difference at both ends of the pore matrix, with the unit of m ;

[0031] t is the test period;

[0032] ,

[0033] In the formula: V 0 is the volume of the pore matrix; unit m 3

[0034] m 2 is the mass of the pore matrix in water in the saturated state;

[0035] m 1 is the mass of the pore matrix in the dry state.

[0036] The present invention has the following beneficial effects: The present invention provides a non-linear seepage velocity equivalent test device for simulating a rock mass with a through crack, which is convenient to manufacture, has a simple, economical and repeatable test method. It can effectively measure the change of the seepage velocity of the rock mass with a through crack at the through crack, can accurately calculate the seepage flow rate of the rock mass with a through crack, and proposes the change law of the non-linear seepage velocity. Description of the Drawings

[0037] Figure 1 is a schematic diagram of the principle of the device of the present invention;

[0038] Figure 2 is a schematic diagram of the permeability;

[0039] Figure 3 is a top view of multiple independent boxes;

[0040] Figure 4 is Figure 3 the schematic diagram in the A-A direction in

[0041] Figure 5 is a schematic diagram of the piezometric part;

[0042] Figure 6 is a schematic diagram when the piezometric part is depressurized. Detailed Embodiments

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with Figures 1-6 in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. If not specifically specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0044] As Figure 1 , a non-linear seepage velocity test device for a rock mass with a through crack, comprising: a water supply part 1, a piezometric part 3, a water seepage part 4, a pore matrix part 5, a through crack 6 and a drainage part 7;

[0045] The output end of the water supply part 1 is communicated with the water seepage part 4, the water seepage part 4 is communicated with the piezometric part 3 and the pore matrix part 5, and the pore matrix part 5 is filled with a pore matrix; the pore matrix is located on both sides of the through crack 6, and the through crack 6 is a hollow structure or partially filled;

[0046] The drainage part 7 includes a number of drainage chambers arranged side by side, and the pore matrix and the through crack 6 are respectively communicated with the corresponding drainage chambers.

[0047] The water supply part 1 is a prior art and can be a combination of a water pump and a water tank, outputting a pressurized water source to the water seepage part 4. The pressure measurement part 3 is used to monitor the real-time pressure of the water seepage part 4. The through crack 6 includes two states, namely a hollow structure without internal filling or partial filling. The two states need to be experimented separately. The water supply part 1 can be communicated with the water seepage part 4 through the water inlet pipe 2. Multiple drainage chambers can be respectively communicated with the beaker 9 through the drain pipe 8 to collect drainage.

[0048] In the present invention, a part of the water source directly enters the drainage chamber through the pore matrix or the drainage chamber, and another part of the water source enters the through crack 6 through the pore matrix and then enters the drainage chamber.

[0049] Specifically, referring to Figure 1 , the drainage volumes of multiple drainage chambers are successively divided into V 1, V 2, V 3... V n , the average flow velocity of the drainage chamber is calculated through the flow rate, the flow velocity distribution curve is drawn, and after the experiment, the pore matrix is taken out, and according to the geotechnical test standard, the porosity of the converted pore matrix is measured n and the permeability K . Referring to Figure 2 , the relationship between the permeability K and different drainage chambers, it can be found that the permeability from the pore matrix to the through crack 6 K is a non-linear change: from the pore matrix on both sides to the through crack 6 in the middle, the permeability K increases non-linearly.

[0050] In addition, in specific implementation, the through crack 6 is preferably arranged in the middle position, that is, the same number of pore matrices are distributed on both sides of the through crack 6. The pore matrix can adopt the multi-porosity combined geological unit simulation material in the prior art.

[0051] The present invention provides a non-linear seepage flow velocity equivalent test device for simulating a rock mass with through cracks, which is convenient to manufacture, has a simple, economical and repeatable test method, can effectively measure the change of the flow velocity of the rock mass with through cracks at the through crack, can calculate the seepage flow rate with through cracks more accurately, and proposes the change law of non-linear seepage flow velocity.

[0052] Such as Figures 3-4 , the pore matrix part 5 includes an independent box body 501, a side-through grid plate 502 and an end grid plate 503; the independent box body 501 is filled with the pore matrix.

[0053] The independent boxes 501 are divided into two groups, with multiple of the independent boxes 501 in each group arranged side by side, and the two groups of independent boxes 501 are spaced apart to form the through crack 6;

[0054] The side-through grid plates 502 are fixedly arranged on the sides of the independent boxes 501, and the end grid plates 503 are arranged at both ends of the independent boxes 501. The two ends of the independent boxes 501 are respectively communicated with the water seepage part 4 and the drainage part 7 through the end grid plates 503; adjacent two independent boxes 501 are communicated through the side-through grid plates 502.

[0055] Specifically, the two groups of independent boxes 501 are symmetrically distributed on both sides of the through crack 6. The independent boxes 501 on both sides only have side-through grid plates 502 arranged on the inner sides, while the independent boxes 501 in the middle have side-through grid plates 502 arranged on both sides. Both the side-through grid plates 502 and the end grid plates 503 are of a mesh plate structure or a screen structure. The side-through grid plates 502 of adjacent two independent boxes 501 are in mutual contact.

[0056] Further, the water seepage part 4 includes a water inlet box body 401. The water inlet box body 401 is communicated with the water supply part 1 and the pressure measurement part 3. A water inlet opening 402 is formed on the side of the water inlet box body 401, and the water inlet opening 402 is communicated with the end grid plate 503.

[0057] Further, the drainage part 7 includes a drainage box body 701, a partition plate 702 and a drain pipe 704;

[0058] A plurality of the partition plates 702 are arranged in the drainage box body 701 to divide the interior of the drainage box body 701 into a plurality of drainage chambers. A drainage opening 703 is formed on the side of the drainage box body 701, and the drainage opening 703 is communicated with the drainage chambers. The plurality of drainage chambers are respectively communicated with the end grid plate 503 and the through crack 6 through the drainage opening 703 in a one-to-one correspondence.

[0059] The end grid plates 503 at both ends are respectively communicated with the water inlet opening 402 and the drainage opening 703. The drainage box body 701, the independent box body 501 and the water inlet box body 401 can be fixedly connected by bolts, and sealing coatings are arranged on the joint surfaces among the three box bodies to avoid water leakage. In addition, a sealing rubber strip 504 is arranged at the bottom of the through crack 6, so that the through crack 6 forms a structure with a top opening. The two side walls of the through crack 6 are the walls of the independent box body 501, and the front and rear ends of the through crack 6 are respectively communicated with the water inlet opening 402 and the drainage opening 703.

[0060] During specific implementation, a part of the water source enters the multiple independent boxes 501 and the through cracks 6 from the water inlet opening 402 and is discharged into the drainage chamber through the drainage opening 703; a part of the water source enters the multiple independent boxes 501 from the water inlet opening 402, enters the adjacent independent box 501 from the side-through grid plate 502, and enters the through crack 6 and is discharged into the drainage chamber through the drainage opening 703.

[0061] In addition, the top of the independent box 501 is an open structure, and the tops of the multiple independent boxes 501 are detachably connected with a cover plate 505 to facilitate filling of the pore matrix. The multiple independent boxes 501 can be filled with the same pore matrix or pore matrices with gradually changing pores.

[0062] Such as Figures 5-6 , the piezometric part 3 includes a piezometer tube 301, a stop block 302, a slider 304, a spring 306 and a piston 307;

[0063] The piezometer tube 301 is arranged vertically, its bottom is communicated with the seepage part 4, the piston 307 is arranged in the piezometer tube 301, the piston 307 is of a hollow structure, the slider 304 can slide through the inside of the piston 307, the top and bottom of the slider 304 are both of a T-shaped structure, the spring 306 is arranged below the T-shaped structure at the top of the slider 304, the spring 306 is sleeved on the slider 304, and the T-shaped structure at the bottom of the slider 304 abuts against the bottom surface of the piston 307;

[0064] The slider 304 is provided with a diversion hole 305 with an upward opening, the side of the slider 304 is provided with a through hole 308 communicating with the diversion hole 305, the inner wall surface of the piston 307 blocks the through hole 308, the stop block 302 is arranged above the slider 304, and the stop block 302 is provided with a pressure relief hole 303 adapted to the diversion hole 305;

[0065] When the piston 307 rises until the slider 304 abuts against the stop block 302, the slider 304 moves downward, so that the through hole 308 moves downward away from the piston 307, so that the through hole 308, the diversion hole 305 and the pressure relief hole 303 communicate with the part of the piezometer tube 301 below the piston 307;

[0066] The piezometer tube 301 is provided with scale lines for piezometry.

[0067] When a water source is filled in the water seepage part 4, a certain water pressure is formed. At this time, the water source below the piston 307 in the piezometer tube 301 pushes the piston 307 to move upward. Since the slider 304 is subjected to the upward thrust of the water source and the thrust of the spring 306, the through hole 308 remains in the piston 307, so that the piston 307 rises. After the piston 307 rises to a certain height and remains unchanged, the water pressure remains stable, and the water pressure value can be obtained through the scale line on the piezometer tube 301.

[0068] When the pore matrix or the drain pipe 8 is blocked and the whole device is abnormal, the piston 307 continues to rise until the slider 304 hits the stop block 302, as Figure 6 shown. At this time, the slider 304 moves downward, the spring 306 is compressed, and then the through hole 308 is separated from the piston 307 and is located below the piston 307. At this time, the through hole 308 connects the piezometer tube 301 parts on both sides of the piston 307, so that the water source enters the through hole 308, the diversion hole 305 and the pressure relief hole 303 in sequence from below the piezometer tube 301, and then is discharged from above the piezometer tube 301 to complete the pressure relief.

[0069] The piezometric part 3 of the present invention can complete two functions of piezometry and pressure relief. The stop block 302 can be connected to the inside of the piezometer tube 301 by threads to adjust the height of the stop block 302, so as to adjust the maximum pressure relief value.

[0070] A non-linear seepage velocity test method for rock mass containing through cracks includes the following steps:

[0071] Step 1, arrange the test device. The water supply part 1, the water seepage part 4, the pore matrix part 5, and the drainage part 7 are connected in sequence. The water seepage part 4 is connected to the piezometric part 3. The pore matrix part 5 is filled with pore matrix, and through cracks 6 are set;

[0072] Step 2, the water supply part 1 supplies water to the water seepage part 4, observes the water pressure of the water seepage part 4 through the piezometric part 3, collects the water output of each drainage chamber, and the water volume of each drainage chamber is recorded as V 1, V 2, V 3... V n , calculate the average flow velocity of the drainage chamber through the flow rate, and draw the flow velocity distribution curve;

[0073] Step 3, after the test is completed, take out the pore matrix, and according to the geotechnical test standard, measure and convert the porosity n and permeability K of the pore matrix, and calculate the flow velocity distribution of the pore matrix through the measured K and n values and the characteristic dimensions of each part of the model.

[0074] Furthermore, in step one, the through crack 6 is a hollow structure or partially filled. When it is partially filled, a plate body is placed in the through crack 6, and a gap is formed between the plate body and the inner wall surface of the through crack 6. Particles are filled in this gap, and then the plate body is taken out to form a partially filled through crack 6; the filling material of the through crack 6 is made by mixing standard sand and cementitious materials, and the sand grains are larger in particle size than those of the pore matrix.

[0075] Furthermore, in step three, the porosity n and the permeability K are obtained by the following formulas:

[0076] ,

[0077] where: Q is the amount of water flowing through the pore matrix part;

[0078] L is the length of the pore matrix;

[0079] A is the cross-sectional area of the pore matrix;

[0080] is the head difference at both ends of the pore matrix, with the unit of m ;

[0081] t is the test period;

[0082] ,

[0083] where: V 0 is the volume of the pore matrix; unit m 3

[0084] m2 is the mass of the pore matrix in water in the saturated state;

[0085] m1 is the mass of the pore matrix in the dry state.

[0086] The embodiments described above are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations, variations, modifications, and substitutions made by those of ordinary skill in the art to the technical solutions of the present invention should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A test device for the non-linear seepage flow velocity of a rock mass with through cracks, characterized in that, Comprising: A water supply part (1), a pressure measuring part (3), a seepage part (4), a pore matrix part (5), a through crack (6) and a drainage part (7); The output end of the water supply part (1) is communicated with the seepage part (4), the seepage part (4) is communicated with the pressure measuring part (3) and the pore matrix part (5), and the pore matrix part (5) is filled with a pore matrix; the pore matrix is located on both sides of the through crack (6), and the through crack (6) is a hollow structure or partially filled; The drainage part (7) includes a plurality of drainage chambers arranged side by side, and the pore matrix and the through crack (6) are respectively communicated with corresponding drainage chambers; The pressure measuring part (3) includes a piezometer tube (301), a stop block (302), a slider (304), a spring (306) and a piston (307); The piezometer tube (301) is arranged vertically, its bottom is communicated with the seepage part (4), the piston (307) is arranged in the piezometer tube (301), the piston (307) is a hollow structure, the slider (304) can slide through the inside of the piston (307), the top and bottom of the slider (304) are both T-shaped structures, the spring (306) is arranged below the T-shaped structure at the top of the slider (304), the spring (306) is sleeved on the slider (304), and the T-shaped structure at the bottom of the slider (304) abuts against the bottom surface of the piston (307); The slider (304) is provided with a diversion hole (305) with an upward opening, the side of the slider (304) is provided with a through hole (308) communicating with the diversion hole (305), the inner wall surface of the piston (307) blocks the through hole (308), the stop block (302) is arranged above the slider (304), and the stop block (302) is provided with a pressure relief hole (303) adapted to the diversion hole (305); When the piston (307) rises to the slider (304) abuts against the stop block (302), the slider (304) moves downwards, so that the through hole (308) moves downward away from the piston (307), so that the through hole (308), the diversion hole (305) and the pressure relief hole (303) communicate with the part of the piezometer tube (301) below the piston (307); The piezometer tube (301) is provided with scale lines for pressure measurement.

2. The non-linear seepage flow velocity testing device for a rock mass with a through crack according to claim 1, wherein, The pore matrix part (5) includes an independent box body (501), a side-through grid plate (502) and an end grid plate (503); the independent box body (501) is filled with a pore matrix; The independent box body (501) is divided into two groups, and a plurality of the independent box bodies (501) in each group are arranged side by side, and the two groups of independent box bodies (501) are spaced apart to form the through crack (6); The side of the independent box body (501) is fixedly provided with the side through-grid plate (502), the end grid plates (503) are arranged at both ends of the independent box body (501), and both ends of the independent box body (501) are respectively communicated with the water seepage part (4) and the drainage part (7) through the end grid plates (503); adjacent two independent box bodies (501) are communicated through the side through-grid plate (502).

3. The non-linear seepage velocity testing device for a rock mass with a through crack according to claim 2, wherein The water seepage part (4) includes a water inlet box body (401), the water inlet box body (401) is communicated with the water supply part (1) and the pressure measurement part (3), a water inlet opening (402) is formed on the side of the water inlet box body (401), and the water inlet opening (402) is communicated with the end grid plate (503).

4. The non-linear seepage velocity testing device for a rock mass with a through crack according to claim 2, characterized in that, The drainage part (7) includes a drainage box body (701), a partition plate (702) and a drain pipe (704); A plurality of partition plates (702) are arranged in the drainage box body (701) to divide the interior of the drainage box body (701) into a plurality of drainage chambers. A drainage opening (703) is arranged on the side of the drainage box body (701), the drainage opening (703) is communicated with the drainage chamber, and the plurality of drainage chambers are respectively communicated with the end grid plate (503) and the through crack (6) through the drainage opening (703).

5. A non-linear seepage velocity testing method for rock masses with through cracks, applied to the testing device described in claim 1, characterized in that, It includes the following steps: Step 1, arrange the test device, the water supply part (1), the water seepage part (4), the pore matrix part (5), and the drainage part (7) are communicated in sequence, the water seepage part (4) is communicated with the pressure measurement part (3), the pore matrix part (5) is filled with pore matrix, and a through crack (6) is set; Step 2: The water supply part (1) supplies water to the water seepage part (4). The water pressure of the water seepage part (4) is observed through the pressure measurement part (3), and the water discharge of each drainage chamber is collected. The water volume of each drainage chamber is recorded in sequence as V 1、 V 2、 V 3…… V n , the average flow velocity of the drainage chamber is calculated through the flow rate, and the flow velocity distribution curve is drawn; Step 3: After the test, take out the pore matrix and measure the porosity of the converted pore matrix according to the geotechnical test standards. n and the permeability K . Through the K and n values and the characteristic dimensions of each part of the model, calculate the flow velocity distribution of the pore matrix.

6. The non-linear seepage flow velocity testing method for a rock mass with a through crack according to claim 5, characterized in that In Step 1, the through crack (6) is of a hollow structure or partially filled. When it is partially filled, a plate body is placed in the through crack (6), a gap is formed between the plate body and the inner wall surface of the through crack (6), particles are filled in the gap, and then the plate body is taken out to form a partially filled through crack (6).

7. A method for testing the non-linear seepage flow velocity of a rock mass with a through crack, as described in claim 5, wherein, In step three, the porosity n and the water permeability K are obtained by the following formula: , Wherein: Q is the amount of water flowing through the pore matrix part; L is the length of the pore matrix; A is the cross-sectional area of the pore matrix; is the head difference between both ends of the pore matrix, with the unit of m ; t is the test period; , In the formula: V 0 is the volume of the pore matrix; unit m 3 m2 is the mass of the pore matrix in the saturated state in water; m1 is the mass of the pore matrix in the dry state.

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