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

Abstract

The invention belongs to the field of experimental research of rock seepage, and provides a non-linear seepage flow velocity testing device and method for rock mass containing through cracks, and the device comprises a water supply part, a pressure measuring part, a water seepage part, a pore matrix part, the through cracks and a drainage part; the output end of the water supply part communicates with the water seepage part, the water seepage part communicates with the pressure measuring part and the pore matrix part, and the pore matrix part is filled with pore matrixes; the pore matrix is located on the two sides of the through crack, and the through crack is of a hollow structure or partially filled; the drainage part comprises a plurality of drainage cavities which are arranged side by side, and the pore matrix and the through cracks are respectively communicated with the corresponding drainage cavities; according to the method, the change condition of the flow velocity of the rock mass with the cut-through crack in the cut-through crack can be effectively measured, the seepage flow containing the cut-through crack can be accurately calculated, and the change rule of the non-linear seepage flow velocity is provided.

Description

Technical Field

[0001] The invention belongs to the field of experimental research on rock seepage, and in particular relates to a nonlinear seepage velocity testing device and method for a rock mass containing through-fractures. Background Art

[0002] The through and non-through cracks, pipes and pore structures in the soil together constitute a complex porous network system. Among them, the through pipe cracks are the main path for the conversion between groundwater and surface water, the important channel for the hydraulic connection between groundwater and rock and soil, and the boundary condition that is often tracked by the instability and failure of rock and soil.

[0003] Since the microstructure of the cracks and pores that make up porous media is extremely complex and irregular, statistical methods are usually used only from a macroscopic perspective when studying seepage problems. That is, the average flow velocity and pressure of the fluid flow on the seepage section (the formation section perpendicular to the fluid flow direction) are mainly studied, rather than studying the flow conditions in individual cracks and pores.

[0004] At present, the seepage velocity test mainly measures the flow velocity of a fixed cross-section, and there has been no discussion on how the seepage velocity varies with the distance from the through-fracture. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a nonlinear seepage velocity testing device and method for a rock mass containing through-fractures to solve the problems in the prior art. The technical solution adopted by the present invention is: A nonlinear seepage velocity testing device for a rock mass with through-cracks, comprising: a water supply part, a pressure measuring part, a water seepage part, a porous matrix part, through-cracks and a drainage part; The output end of the water supply part is connected to the water seepage part, and the water seepage part is connected to the pressure measuring part and the porous matrix part, and the porous matrix part is filled with a porous matrix; the porous 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 plurality of drainage chambers arranged side by side, and the porous matrix and the through cracks are respectively connected with the corresponding drainage chambers.

[0006] Furthermore, the porous matrix part includes an independent box, a side-passing mesh plate and an end mesh plate; the independent box is filled with a porous matrix.

[0007] The independent boxes are divided into two groups, and a plurality of independent boxes in each group are arranged side by side, and the two groups of independent boxes are spaced apart to form the through cracks; The side mesh plate is fixedly arranged on the side of the independent box body, and the end mesh plates are arranged at both ends of the independent box body. The two ends of the independent box body are respectively connected to the seepage part and the drainage part through the end mesh plates; the two adjacent independent boxes are connected through the side mesh plates.

[0008] Furthermore, the water seepage part includes a water inlet box body, the water inlet box body is connected to the water supply part and the pressure measuring part, and a water inlet opening is provided on the side of the water inlet box body, and the water inlet opening is connected to the end grid plate.

[0009] Further, the drainage part includes a drainage box, a partition and a drainage pipe; A plurality of partitions 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 connected to the drainage chamber. The plurality of drainage chambers are connected to the end mesh plates and the through cracks through the drainage openings in a one-to-one correspondence.

[0010] Furthermore, the pressure measuring part includes a pressure measuring tube, a stopper, a slider, a spring and a piston; The pressure measuring tube is arranged vertically, and its bottom is connected to the water seepage part. The piston is arranged in the pressure measuring tube, and the piston is a hollow structure. The slider can slide through the inside of the piston. The top and bottom of the slider are both T-shaped structures. The spring is arranged below the T-shaped structure at the top of the slider, and 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. The slider is provided with a guide hole with an upward opening, a through hole connected to the guide hole is provided on the side of the slider, the inner wall surface of the piston blocks the through hole, the stopper is provided above the slider, and the stopper is provided with a pressure relief hole adapted to the guide hole; When the piston rises until the slider abuts against the stopper, the slider moves downward, causing the through hole to move downward away from the piston, thereby allowing the through hole, the flow guide hole and the pressure relief hole to communicate with the portion of the pressure measuring tube located below the piston; The pressure measuring tube is provided with scale lines for measuring pressure.

[0011] A method for testing nonlinear seepage velocity in a rock mass containing through-fractures comprises the following steps: Step 1: Arrange the test device, connect the water supply part, the water seepage part, the porous matrix part, and the drainage part in sequence, connect the water seepage part to the pressure measurement part, fill the porous matrix part with porous matrix, and set through cracks; Step 2: The water supply part supplies water to the seepage part, and the water pressure of the seepage part is observed by the pressure measuring part, and the water output of each drainage chamber is collected. The water volume of each drainage chamber is recorded as V1, V2 , V3 … V n , calculate the average flow velocity in the drainage chamber through the flow rate, and draw the flow velocity distribution curve; Step 3: After the test, take out the porous matrix and determine the porosity of the converted porous matrix according to the geotechnical test standard. n and water permeability K , which passed the test K and n The velocity distribution of the porous matrix is ​​calculated based on the values ​​and characteristic dimensions of the model.

[0012] Furthermore, in step one, the through crack is a hollow structure or is partially filled. When partially filled, a plate is placed in the through crack to form a gap between the plate and the inner wall of the through crack, and particles are filled in the gap. The plate is then taken out to form a partially filled through crack.

[0013] Furthermore, in step 3, the porosity n and water permeability K Obtained by the following formula: , Where: Q is the amount of water flowing through the porous matrix part; L is the length of the porous matrix; A is the cross-sectional area of ​​the porous matrix; is the hydraulic head difference at both ends of the porous matrix, in units of m ; t The test period; , Where: V 0 is the volume of the porous matrix; the unit m 3 m 2 is the mass of the pore matrix in water at saturation; m 1 is the mass of the porous matrix in dry state.

[0014] The present invention has the following beneficial effects: the present invention proposes a nonlinear seepage velocity equivalent test device for simulating rock masses containing through-fractures, which is easy to manufacture, has a simple, economical and repeatable test method, can effectively measure the change of the velocity of the rock masses containing through-fractures at the through-fractures, can more accurately calculate the seepage flow rate containing through-fractures, and proposes the change law of the nonlinear seepage velocity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram showing the principle of the device of the present invention; Figure 2 It is a schematic diagram of water permeability; Figure 3 It is a top view of multiple independent boxes; Figure 4 yes Figure 3 Schematic diagram of the middle AA direction; Figure 5 It is a schematic diagram of the pressure measurement part; Figure 6 It is a schematic diagram of the pressure measuring part when the pressure is released. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention Figure 1-Figure 6 , the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0017] like Figure 1 , a nonlinear seepage velocity testing device for a rock mass containing through-fractures, comprising: a water supply part 1, a pressure measuring part 3, a water seepage part 4, a porous matrix part 5, through-fractures 6 and a drainage part 7; The output end of the water supply part 1 is connected to the water seepage part 4, and the water seepage part 4 is connected to the pressure measuring part 3 and the porous matrix part 5. The porous matrix part 5 is filled with a porous matrix; the porous 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 portion 7 includes a plurality of drainage chambers arranged side by side, and the porous matrix and the through cracks 6 are respectively connected to the corresponding drainage chambers.

[0018] The water supply part 1 is a prior art, which 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 measuring 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 with no filling inside or a partially filled structure. The two states need to be tested separately. The water supply part 1 can be connected to the water seepage part 4 through the water inlet pipe 2. Multiple drainage chambers can be connected to the beaker 9 through the drainage pipe 8 to collect drainage.

[0019] In the present invention, a part of the water source directly enters the drainage chamber through the porous matrix or the drainage chamber, and another part of the water source enters the through cracks 6 through the porous matrix and then enters the drainage chamber.

[0020] Specifically, refer to Figure 1 , the drainage volume of multiple drainage chambers is divided intoV 1. V 2. V 3…… V n The average flow rate of the drainage chamber is calculated by the flow rate, and the flow rate distribution curve is drawn. After the experiment, the porous matrix is ​​taken out and the porosity of the converted porous matrix is ​​determined according to the geotechnical test standard. n and water permeability K . refer to Figure 2 , water permeability K The relationship between the different drainage cavities shows that the permeability from the pore matrix to the through cracks6 K It is a nonlinear change: from the porous matrix on both sides to the through cracks in the middle, the permeability K Non-linear increase.

[0021] In addition, in specific implementation, the through fracture 6 is preferably arranged in the middle position, that is, an equal number of porous matrices are distributed on both sides of the through fracture 6. The porous matrix can be a multi-porous combined geological unit simulation material in the prior art.

[0022] The present invention proposes a nonlinear seepage velocity equivalent test device for simulating rock masses containing through-fractures, which is easy to manufacture, has a simple, economical and repeatable testing method, can effectively measure the change of the velocity of the rock masses containing through-fractures in the through-fractures, can more accurately calculate the seepage flow rate containing through-fractures, and proposes the change law of the nonlinear seepage velocity.

[0023] like Figure 3-Figure 4 The porous matrix part 5 includes an independent box 501, a side mesh plate 502 and an end mesh plate 503; the independent box 501 is filled with a porous matrix.

[0024] The independent boxes 501 are divided into two groups, and a plurality of independent boxes 501 are arranged side by side in each group, and the two groups of independent boxes 501 are spaced apart to form the through cracks 6; The side-passing mesh plate 502 is fixedly arranged on the side of the independent box 501, and the end mesh plates 503 are arranged at both ends of the independent box 501. The two ends of the independent box 501 are respectively connected to the seepage part 4 and the drainage part 7 through the end mesh plates 503; the two adjacent independent boxes 501 are connected through the side-passing mesh plates 502.

[0025] Specifically, two groups of independent boxes 501 are symmetrically distributed on both sides of the through crack 6. The independent boxes 501 located on both sides are only provided with side-passing mesh panels 502 on the inner side, while the independent box 501 located in the middle is provided with side-passing mesh panels 502 on both sides. The side-passing mesh panels 502 and the end mesh panels 503 are both mesh plate structures or screen structures. The side-passing mesh panels 502 of two adjacent independent boxes 501 are attached to each other.

[0026] Furthermore, the water seepage part 4 includes a water inlet box 401 , which is connected to the water supply part 1 and the pressure measuring part 3 . A water inlet opening 402 is provided on the side of the water inlet box 401 , and the water inlet opening 402 is connected to the end grid plate 503 .

[0027] Furthermore, the drainage part 7 includes a drainage box 701, a partition 702 and a drainage pipe 704; A plurality of partitions 702 are arranged in the drainage box 701, dividing the interior of the drainage box 701 into a plurality of drainage chambers. A drainage opening 703 is arranged on the side of the drainage box 701, and the drainage opening 703 is connected to the drainage chamber. The plurality of drainage chambers are connected to the end mesh plate 503 and the through crack 6 through the drainage opening 703 in a one-to-one correspondence.

[0028] The end grid plates 503 at both ends are connected to the water inlet opening 402 and the drainage opening 703 respectively. The drainage box 701, the independent box 501 and the water inlet box 401 can be fastened by bolts, and a sealing coating is provided on the joint surfaces of the three boxes to prevent water leakage. In addition, a sealing rubber strip 504 is provided at the bottom of the through crack 6, so that the through crack 6 forms a top-opening structure, the two side walls of the through crack 6 are the walls of the independent box 501, and the front and rear ends of the through crack 6 are connected to the water inlet opening 402 and the drainage opening 703 respectively.

[0029] During specific implementation, a portion 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 from the drainage opening 703; a portion of the water source enters the multiple independent boxes 501 from the water inlet opening 402, enters the adjacent independent boxes 501 from the side grid plate 502, and enters the through cracks 6 and is discharged into the drainage chamber through the drainage opening 703.

[0030] In addition, the top of the independent box 501 is an open structure, and the tops of the multiple independent boxes 501 can be detachably connected to the cover plate 505 to facilitate filling of the porous matrix. The multiple independent boxes 501 can be filled with the same porous matrix, or filled with a porous matrix with gradually changing pores.

[0031] like Figure 5-Figure 6The pressure measuring part 3 includes a pressure measuring tube 301, a stopper 302, a slider 304, a spring 306 and a piston 307; The pressure measuring tube 301 is vertically arranged, and its bottom is connected to the water seepage part 4. The piston 307 is arranged in the pressure measuring 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. 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 guide hole 305 with an opening facing upward, a through hole 308 connected to the guide hole 305 is provided on the side of the slider 304, the inner wall surface of the piston 307 blocks the through hole 308, the stopper 302 is provided above the slider 304, and the stopper 302 is provided with a pressure relief hole 303 adapted to the guide hole 305; When the piston 307 rises until the slider 304 abuts against the stopper 302, the slider 304 moves downward, causing the through hole 308 to move downward away from the piston 307, so that the through hole 308, the guide hole 305 and the pressure relief hole 303 are connected to the portion of the pressure measuring tube 301 located below the piston 307; The pressure measuring tube 301 is provided with scale lines for measuring pressure.

[0032] When water is filled into the seepage part 4, a certain water pressure is formed. At this time, the water source in the pressure measuring tube 301 and below the piston 307 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 pressure measuring tube 301.

[0033] When the porous matrix or the drain pipe 8 is blocked, the entire device is abnormal, and the piston 307 continues to rise until the slider 304 hits the stopper 302. Figure 6 At this time, the slider 304 moves downward and the spring 306 is compressed, so the through hole 308 is separated from the piston 307 and is located below the piston 307. At this time, the through hole 308 is connected to the pressure measuring tube 301 on the upper and lower sides of the piston 307, so that the water source enters the through hole 308, the guide hole 305 and the pressure relief hole 303 from the bottom of the pressure measuring tube 301 in turn, and then is discharged from the top of the pressure measuring tube 301 to complete the pressure relief.

[0034] The pressure measuring part 3 of the present invention can perform two functions: pressure measuring and pressure relief. The stopper 302 can be connected to the inside of the pressure measuring tube 301 by threading to adjust the height of the stopper 302, thereby adjusting the maximum pressure relief value.

[0035] A method for testing nonlinear seepage velocity in a rock mass containing through-fractures comprises the following steps: Step 1: Arrange the test device, the water supply part 1, the water seepage part 4, the porous matrix part 5, and the drainage part 7 are connected in sequence, the water seepage part 4 is connected to the pressure measuring part 3, the porous matrix part 5 is filled with porous matrix, and a through crack 6 is set; Step 2: The water supply part 1 supplies water to the water seepage part 4, and the water pressure of the water seepage part 4 is observed by the pressure measuring part 3, and the water output of each drainage chamber is collected. The water volume of each drainage chamber is recorded as V 1. V 2. V 3…… V n , calculate the average flow velocity in the drainage chamber through the flow rate, and draw the flow velocity distribution curve; Step 3: After the test, take out the porous matrix and determine the porosity of the converted porous matrix according to the geotechnical test standard. n and water permeability K , which passed the test K and n The velocity distribution of the porous matrix is ​​calculated based on the values ​​and characteristic dimensions of the model.

[0036] Furthermore, in step one, the through-crack 6 is a hollow structure or is partially filled. When partially filled, a plate is placed in the through-crack 6 to form a gap with the inner wall of the through-crack 6, and particles are filled in the gap. The plate is then taken out to form a partially filled through-crack 6; the filling of the through-crack 6 is made by mixing standard sand and a binder material, and the sand grain size is larger than that of the porous matrix.

[0037] Furthermore, in step 3, the porosity n and water permeability K Obtained by the following formula: , Where: Q is the amount of water flowing through the porous matrix part; L is the length of the porous matrix; A is the cross-sectional area of ​​the porous matrix; is the hydraulic head difference at both ends of the porous matrix, in units of m ; t The test period; , Where: V 0 is the volume of the porous matrix; the unit m 3 m2 is the mass of the pore matrix in water at saturated state; m1 is the mass of the porous matrix in the dry state.

[0038] The embodiments described above are only descriptions of the preferred modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations, modifications, and substitutions made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A nonlinear seepage velocity testing device for a rock mass containing through-fractures, characterized in that: include: Water supply part (1), pressure measurement part (3), water seepage part (4), porous matrix part (5), through-fracture (6) and drainage part (7); The output end of the water supply part (1) is connected to the water seepage part (4), and the water seepage part (4) is connected to the pressure measuring part (3) and the porous matrix part (5), and the porous matrix part (5) is filled with a porous matrix; the porous matrix is ​​located on both sides of the through-crack (6), and the through-crack (6) is a hollow structure or is partially filled; The drainage portion (7) comprises a plurality of drainage chambers arranged side by side, and the porous matrix and the through cracks (6) are respectively connected to corresponding drainage chambers.

2. The nonlinear seepage velocity testing device for rock mass with through fractures according to claim 1, characterized in that: The porous matrix portion (5) comprises an independent box (501), a side mesh plate (502) and an end mesh plate (503); the independent box (501) is filled with a porous matrix; The independent boxes (501) are divided into two groups, and a plurality of the independent boxes (501) are arranged side by side in each group. The two groups of independent boxes (501) are spaced apart to form the through cracks (6); The side-passing mesh plate (502) is fixedly arranged on the side of the independent box (501), and the end mesh plates (503) are arranged at both ends of the independent box (501); the two ends of the independent box (501) are respectively connected to the water seepage part (4) and the drainage part (7) through the end mesh plates (503); and two adjacent independent boxes (501) are connected through the side-passing mesh plates (502).

3. The nonlinear seepage velocity testing device for rock mass with through fractures according to claim 2, characterized in that: The water seepage part (4) comprises a water inlet box (401), the water inlet box (401) being connected to the water supply part (1) and the pressure measuring part (3), a water inlet opening (402) being provided on a side of the water inlet box (401), the water inlet opening (402) being connected to the end grid plate (503).

4. The nonlinear seepage velocity testing device for rock mass with through-fractures according to claim 2, characterized in that: The drainage part (7) comprises a drainage box (701), a partition (702) and a drainage pipe (704); A plurality of partitions (702) are arranged in the drainage box (701), dividing the interior of the drainage box (701) into a plurality of drainage chambers. A drainage opening (703) is arranged on the side of the drainage box (701), and the drainage opening (703) is connected to the drainage chamber. The plurality of drainage chambers are connected to the end mesh plate (503) and the through crack (6) in a one-to-one correspondence through the drainage opening (703).

5. The nonlinear seepage velocity testing device for rock mass with through-fractures according to claim 1, characterized in that: The pressure measuring part (3) comprises a pressure measuring tube (301), a stopper (302), a slider (304), a spring (306) and a piston (307); The pressure measuring tube (301) is arranged vertically, and its bottom is connected to the water seepage part (4). The piston (307) is arranged in the pressure measuring 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). 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 guide hole (305) opening upward, a through hole (308) communicating with the guide hole (305) is provided on the side of the slider (304), the inner wall surface of the piston (307) blocks the through hole (308), the stopper (302) is provided above the slider (304), and the stopper (302) is provided with a pressure relief hole (303) adapted to the guide hole (305); When the piston (307) rises until the slider (304) abuts against the stopper (302), the slider (304) moves downward, causing the through hole (308) to move downward away from the piston (307), thereby allowing the through hole (308), the flow guide hole (305) and the pressure relief hole (303) to communicate with the portion of the pressure measuring tube (301) located below the piston (307); The pressure measuring tube (301) is provided with scale lines for measuring pressure.

6. A method for testing the nonlinear seepage velocity of a rock mass containing through-fractures, applied to the testing device according to claim 1, characterized in that: The following steps are involved: Step 1: Arrange the test device, the water supply part (1), the water seepage part (4), the porous matrix part (5), and the drainage part (7) are connected in sequence, the water seepage part (4) is connected to the pressure measuring part (3), the porous matrix part (5) is filled with porous matrix, and a through crack (6) is set; Step 2: The water supply part (1) supplies water to the water seepage part (4), and the water pressure of the water seepage part (4) is observed by the pressure measuring part (3), and the water output of each drainage chamber is collected. The water volume of each drainage chamber is recorded as V 1. V 2. V 3…… V n , calculate the average flow velocity in the drainage chamber through the flow rate, and draw the flow velocity distribution curve; Step 3: After the test, take out the porous matrix and determine the porosity of the converted porous matrix according to the geotechnical test standard. n and water permeability K , which passed the test K and n The velocity distribution of the porous matrix is ​​calculated based on the values ​​and characteristic dimensions of the model.

7. A nonlinear seepage velocity test method for a rock mass containing through fractures according to claim 6, characterized in that: In step 1, the through crack (6) is a hollow structure or is partially filled. When partially filled, a plate is placed in the through crack (6), and a gap is formed between the plate and the inner wall of the through crack (6). Particles are filled in the gap, and then the plate is taken out to form a partially filled through crack (6).

8. The method for testing nonlinear seepage velocity of a rock mass containing through fractures according to claim 6, characterized in that: In step 3, the porosity n and water permeability K Obtained by the following formula: , Where: Q is the amount of water flowing through the porous matrix part; L is the length of the porous matrix; A is the cross-sectional area of ​​the porous matrix; is the hydraulic head difference at both ends of the porous matrix, in units of m ; t The test period; , Where: V 0 is the volume of the porous matrix; the unit m 3 m2 is the mass of the pore matrix in water at saturated state; m1 is the mass of the porous matrix in the dry state.

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