CN118278067B - Calculation method of precise control of grouting volume behind dam under high water head conditions - Google Patents

Abstract

The present invention discloses a method for calculating the precise control of grouting injection volume behind a dam under high head conditions, and belongs to the field of reservoir leakage treatment in water conservancy and hydropower engineering. The present invention constructs a quantitative calculation model for grouting volume under high head conditions, based on the grouting diffusion theory and the shear strength theory of the plugging body, and comprehensively considers the main factors that have a significant impact on the grouting volume, such as the head, grouting pipeline, grouting water stop box, plugging body, pore size, and rock micro-crack distribution. The grouting volume can be accurately calculated and controlled, and the problems of inaccurate calculation, serious waste, and lack of theoretical guidance in the past are solved, thereby providing a good theoretical basis for the cost estimation and construction preparation of this technology.

Description

Calculation method of precise control of grouting volume behind dam under high water head conditions

Technical Field

The present invention belongs to the field of reservoir leakage treatment in water conservancy and hydropower engineering, and specifically relates to a method for calculating the amount of grouting accurately controlled behind a dam under high water head conditions.

Background Art

During the construction or long-term operation of water conservancy and hydropower projects, leakage problems often occur through karst pipes, rock pores and rock fissures under high head conditions, especially in karst areas, where the frequency of occurrence is more common. Most leakage channels are connected to river water or reservoir water, and the infiltration ports are generally located underwater or even in deep water areas. It is very difficult to find out the number and location of infiltration ports. Moreover, under high head and high flow rate conditions, whether it is the plugging of the infiltration ports or the plugging in the middle, there are problems such as large engineering volume, high cost, complex construction and long construction period due to the moving water carrying away the plugging materials. During the construction of the project or the commissioning of water storage and operation, leakage problems with high head and large flow are prone to occur, and it is not feasible or ineffective to adopt the entrance or middle plugging. Therefore, the current measures of grouting plugging behind the dam or in the corridor are mostly adopted. However, the biggest problem with this technology is that the grouting volume cannot be accurately measured during grouting, and therefore the grouting cannot be "precisely" controlled according to the grouting volume. During actual construction, the construction workers can only rely on their engineering experience and "feel" to grout, which often results in the grouting volume far exceeding the actual needs of the project, causing huge waste.

The technology of precise control of grouting behind the dam is difficult, and there are many factors that affect the grouting volume, among which the main factors include the head difference between upstream and downstream, the size and distribution of leakage channels, pore distribution, degree of fissure development, flow velocity, rock mass conditions, grouting pressure, etc. The slurry not only needs to fill the leakage pipe itself, but also needs to fill the pores in the rock mass within a certain range around the leakage channel and the micro-cracks within the diffusion range. At the same time, the plugging body is also required to meet the shear strength and stability requirements under high head conditions. Therefore, in order to achieve the purpose of precise control of grouting, the grouting volume that meets the engineering requirements must be accurately calculated.

Under high head conditions, many reservoirs have pipe-type, pore-type or fissure-type leakage behind the dam or in the corridor. Generally, controlled grouting is carried out behind the dam or in the corridor. The key to implementing this technology is to accurately calculate the grouting volume before construction, thereby providing a theoretical basis for cost estimation and construction preparation.

Summary of the invention

In view of the problem that there is no accurate theoretical calculation method for the grouting volume behind the dam or in the corridor under high head conditions (the existing literature fails to fully consider the grouting diffusion radius, pipeline, water stop box, and the grouting consumption of the front arc accumulation area in the leakage pipeline), the purpose of the present invention is to provide a method for calculating the grouting volume behind the dam under high head conditions. The present invention comprehensively considers the main factors that affect the grouting volume, such as water head, grouting pipeline, water stop box (box), plugging body, pore distribution, and rock micro-crack size, and establishes a theoretical model. By calculating the grouting components of each part, the possible grouting volume can be accurately calculated, which solves the problems of inaccurate calculation of grouting (ash consumption), construction following "feelings", and lack of theoretical guidance. The grouting volume calculated according to the method of the present invention can "precisely" control grouting under the premise of ensuring safety, reduce slurry waste, and effectively save engineering investment.

To achieve the above object, the present invention is implemented by the following technical solutions:

A method for calculating the amount of grouting to be accurately controlled behind a dam under high head conditions, characterized in that it comprises the following steps:

S1. Obtain the upstream reservoir water elevation Elevation of leakage channel outlet ;

S2. Get the approximate radius of the leakage channel ;

S3. Obtaining the porosity in the rock mass , and the radius of the larger pores directly connected to the leakage channel With length ;

S4. Determine the diameter of the grouting pipe With length , calculate the volume of the pipeline occupied by the slurry ;

S5, select the appropriate size , , Calculate the volume of the grouting water stop box ;

S6. Based on the acquired upstream reservoir water elevation , Leakage channel outlet elevation and the approximate radius of the leakage channel , calculate the length of the main section of the grouting plugging body With volume ;

S7. After the main section of the grouting plugging body is formed, the slurry will gradually accumulate at the front to form an irregular arc-shaped accumulation area, which is the auxiliary section of the grouting plugging body. Calculate the length of the auxiliary section of the grouting plugging body. With volume ;

S8, based on the radius of the larger pores directly connected to the leakage channel With length , calculate the volume of slurry that fills the larger pores directly connected to the leakage channel ;

S9. Approximate radius of the leakage channel based on the obtained , porosity in rock mass and the length of the main section of the grouting plugging body , calculate the volume of slurry diffused into the micro-cracks of the rock mass ;

S10. Consider the safety factor and summarize the calculation , , , , , ,get ;

S11. Based on the density and , calculate the ash consumption of grouting ;

S12. Determine the amount of ash consumed in grouting Whether the following corresponding relationship is satisfied: When the water leakage behind the dam is Q<0.5m ³ /s, the grouting ash consumption is 50~100t; When the water leakage behind the dam is 0.5m ³ /s<Q<1m ³ /s, the grouting ash consumption is 100~150t; When the water leakage behind the dam Q>1m ³ /s, the grouting ash consumption is 150~200t; if it meets the requirements, it is reasonable and ends; if it does not meet the requirements, it is unreasonable and the above steps are repeated.

Preferably, in step S4, the volume The calculation formula is as follows:

(1)

In formula (1), , are the diameter and length of the grouting pipe respectively.

Preferably, in step S5, the volume The calculation formula is as follows:

(2)

In formula (2), , , They are the length, width and height of the grouting water stop box respectively.

Preferably, in step S6, the length With volume The calculation formula is as follows:

(3)

(4)

In formulas (3) and (4), is the anti-slip stability safety factor; is the density of the water body; , They are the upstream reservoir water elevation and the leakage channel outlet elevation respectively; is the approximate radius of the leakage channel; is the cohesion of the plugging body; It is the effective contact coefficient between the main section of the grouting sealing body and the rock mass.

Preferably, in step S7, the length With volume The calculation formula is as follows:

(5)

(6)

In formulas (5) and (6), is the length of the main section of the grouting plugging body; is the approximate radius of the leakage channel.

Preferably, in step S8, the volume The calculation formula is as follows:

= (7)

= (8)

In equations (7) and (8), N is the number of larger pores directly connected to the leaking pipe; is the radius of the i-th larger pore; is the length of the i-th larger pore; is the volume of slurry filled in the i-th larger pore.

Preferably, in step S9, the volume The calculation formula is as follows:

(9)

(10)

In formulas (9) and (10), is the porosity in the rock mass, R is the diffusion radius, , , They are the dry bulk density, specific gravity and water bulk density of the rock mass respectively.

Preferably, in step S9, the volume The calculation formula is as follows:

(11)

In formula (11), , , , , , They are the volume safety factors corresponding to the volume of the grouting pipeline, the volume of the grouting waterstop box, the volume of the main section of the grouting sealing body, the volume of the auxiliary section of the grouting sealing body, the volume of the slurry diffused into the micro-cracks of the rock mass, and the volume of the slurry filling the larger pores connected to the leakage channel.

Preferably, in step S10, the grouting ash consumption is The calculation formula is as follows:

(12)

In formula (12), is the density of the slurry with corresponding water-cement ratio.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1) The measurement of grouting (ash consumption) under high head conditions is a major problem. The present invention solves the problems of inaccurate calculation, serious waste and lack of theoretical guidance in the past.

2) The present invention comprehensively considers the main factors affecting the calculation of the injection (ash consumption) amount, such as head difference, grouting pipeline, water stop box (box), plugging body, pores, rock microcracks, and accumulation body at the front end of the pipeline, which is more scientific and more in line with the actual situation.

3) The present invention can provide a better theoretical basis for accurately controlling the cost estimation and construction preparation of grouting projects.

4) The grouting volume calculated by the method of the present invention can be “precisely” controlled under the premise of ensuring safety.

Make grouting, reduce slurry waste and save project investment.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a calculation model for accurately controlling the grouting volume behind the dam.

FIG. 2 is a flow chart of the design of the present invention.

In the figure: 1-water retaining structure; 2-rock mass; 3-water body; 4-mountain corridor or foundation pit behind the dam; 5-leakage channel; 6-grouting pipe; 7-grouting water stop box; 8-larger pores; 9-main section of grouting sealing body; 10-auxiliary section of grouting sealing body.

DETAILED DESCRIPTION

The specific implementation modes of the present invention are described below in conjunction with the accompanying drawings so that those skilled in the art can understand the present invention. Obviously, the present invention is not limited to the scope of the specific implementation modes.

As shown in FIGS. 1 and 2 , the present invention provides a method for calculating the amount of grouting accurately controlled behind a dam under high head conditions, comprising the following steps:

S1. Obtain the upstream reservoir water elevation through on-site investigation and data collection Elevation of leakage channel outlet ;

S2. Obtain the approximate radius of the leakage channel 5 by analytical estimation, geological drilling or other geophysical exploration methods. ;

S3. Obtain the porosity of rock mass 2 by consulting engineering geological survey data , and the radius of the larger pore 8 directly connected to the leakage channel 5 With length ;

S4. According to the actual needs of the site, select the grouting pipeline layout and determine the diameter of the grouting pipe 6 With length , calculate the volume of the pipeline occupied by the slurry ;

Among them, the volume The calculation formula is as follows:

(1)

In formula (1), , are the diameter and length of the grouting pipe 6 respectively, which are used to calculate the grouting volume occupied by the pipeline.

S5, according to the outlet water volume of the leakage channel 5, the construction space of the mountain corridor or the foundation pit 4 behind the dam, select the appropriate size respectively , , 7. Calculate the volume of the grouting water stop box. ;

Among them, the volume The calculation formula is as follows:

(2)

In formula (2), , , They are respectively the length, width and height of the grouting water-stopping box 7, which are selected according to the actual situation on site.

S6. According to the current hydraulic tunnel design specifications of the water conservancy or hydropower industry, and in accordance with the shear resistance theory of the plugging body, the anti-sliding stability safety factor Under the requirement of not less than 3.0, calculate the length of the main section 9 of the grouting plugging body Assuming that the leakage channel 5 is cylindrical, the volume of the main section 9 of the grouting plugging body is calculated. ;

Among them, the length With volume The calculation formula is as follows:

(3)

(4)

In formulas (3) and (4), is the anti-slip stability safety factor; is the density of water body 3; , They are the upstream reservoir water elevation and the leakage channel outlet elevation respectively; is the approximate radius of the leakage channel; is the cohesion of the plugging body; It is the effective contact coefficient between the main section of the grouting sealing body and the rock mass, which is generally taken as 0.5~0.7.

S7. After the main section 9 of the grouting plugging body is formed, the slurry will gradually accumulate at the front end to form an irregular arc-shaped accumulation area, which is the auxiliary section 10 of the grouting plugging body. Calculate the length of the auxiliary section 10 of the grouting plugging body. With volume ;

Among them, the length With volume The calculation formula is as follows:

(5)

(6)

In formulas (5) and (6), is the length of the main section of the grouting plugging body; is the approximate radius of the leakage channel; according to formula (6), the volume of the auxiliary section of the grouting plugging body is approximately calculated according to the triangular columnar accumulation form. Calculation.

S8. Under high pressure, the slurry fills the leakage channel 5 and also fills the larger pores 8 directly connected to the leakage pipe. The volume of the slurry that fills the larger pores 8 directly connected to the leakage channel 5 is calculated. ;

Among them, the volume The calculation formula is as follows:

= (7)

= (8)

In equations (7) and (8), N is the number of larger pores directly connected to the leaking pipe; is the radius of the i-th larger pore; is the length of the i-th larger pore; is the volume of slurry filled in the i-th larger pore.

S9. Similarly, under high-pressure grouting conditions, in addition to filling the leakage channel and the larger pores directly connected to the leakage pipe, the slurry will also diffuse into the nearby rock microcracks. Calculate the slurry volume diffused into the rock microcracks ;

Among them, the volume The calculation formula is as follows:

(9)

(10)

In formulas (9) and (10), is the porosity in the rock mass, , , They are the dry bulk density, specific gravity and water bulk density of the rock mass respectively.

S10. Consider the safety factor (margin) and summarize the calculation , , , , , ,get ;

Among them, the volume The calculation formula is as follows:

(11)

In formula (11), , , , , , The volume safety factors are the volume occupied by the grouting pipeline, the volume of the grouting waterstop box, the volume of the main section of the grouting sealing body, the volume of the auxiliary section of the grouting sealing body, the volume of the slurry diffused into the micro-cracks of the rock mass, and the volume of the slurry filling the larger pores connected to the leakage channel, which are generally taken as 2.0~2.5.

S11. Calculate the grouting ash consumption based on the density of the slurry with the corresponding water-cement ratio (e.g. water-cement ratio 3:1, 2:1, 1:1 or 0.5:1). , guide on-site construction.

Among them, the ash consumption of grouting The calculation formula is as follows:

(12)

In formula (12), is the density of the slurry with corresponding water-cement ratio.

S12. Determine the amount of ash consumed in grouting Whether the following corresponding relationship is satisfied: When the water leakage behind the dam is Q<0.5m ³ /s, the grouting ash consumption is 50~100t; When the water leakage behind the dam is 0.5m ³ /s<Q<1m ³ /s, the grouting ash consumption is 100~150t; When the water leakage behind the dam Q>1m ³ /s, the grouting ash consumption is 150~200t; if it meets the requirements, it is reasonable and ends; if it does not meet the requirements, it is unreasonable and the above steps are repeated.

In summary, the present invention constructs a quantitative calculation model for the grouting (ash consumption) amount under high head conditions, based on the grouting diffusion theory and the shear strength theory of the plugging body, and comprehensively considers the main factors that have a significant impact on the grouting (ash consumption) amount, such as the head, grouting pipeline, water stop box, plugging body, pore size, and rock microcrack distribution. The grouting (ash consumption) amount can be accurately calculated and controlled, which solves the problems of inaccurate calculation, serious waste, and lack of theoretical guidance in the past, thereby providing a good theoretical basis for the cost estimation and construction preparation of this technology.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims (2)

1. The method for accurately controlling grouting filling amount after the dam under the condition of high water head is characterized by comprising the following steps of:

S1, acquiring an upstream reservoir Shui Gaocheng H _{Water and its preparation method} and a leakage channel outlet elevation H ₀;

S2, obtaining an approximate radius R _{Blocking up} of the leakage channel;

s3, acquiring the porosity n in the rock mass, and the radius r and the length l of a larger pore directly connected with the seepage channel;

S4, determining the diameter d _Pipe and the length L _Pipe of the grouting pipe, and calculating the volume V _Pipe of the pipeline occupied by the slurry;

s5, selecting proper grouting water stop boxes with the sizes of L _{Box (BW)} 、B _{Box (BW)} 、H _{Box (BW)} respectively, and calculating the volume V _{Box (BW)} of the grouting water stop boxes;

S6, calculating the length L _{Blocking up 1} and the volume V _{Blocking up 1} of the grouting plug body main body section based on the obtained upstream reservoir Shui Gaocheng H _{Water and its preparation method} , the leakage channel outlet elevation H ₀ and the approximate radius R _{Blocking up} of the leakage channel;

S7, after the main body section of the grouting plugging body is formed, slurry is gradually accumulated at the front end to form an irregular arc accumulation area, namely an auxiliary section of the grouting plugging body, and the length L _{Blocking up 2} and the volume V _{Blocking up 2} of the auxiliary section of the grouting plugging body are calculated;

S8, calculating the slurry volume V _{Pores of the material} of the slurry filled in the larger pore directly connected with the leakage channel based on the obtained radius r and length l of the larger pore directly connected with the leakage channel;

S9, calculating the slurry volume V _{Diffusion of} of slurry diffused into the micro-cracks of the rock mass based on the approximate radius R _{Blocking up} of the acquired leakage channel, the porosity n in the rock mass and the length L _{Blocking up 1} of the main body section of the grouting plugging body;

s10, considering safety coefficients, and summarizing and calculating V _Pipe 、V _{Box (BW)} 、V _{Blocking up 1}、V _{Blocking up 2}、V _{Pores of the material} 、V _{Diffusion of} to obtain V _{Total (S)} ;

s11, calculating the grouting ash consumption m _{Ash of ash} based on the density and V _{Total (S)} of the adopted corresponding water-ash ratio slurry;

S12, judging whether the grouting ash consumption m _{Ash of ash} meets the following corresponding relation: when the water leakage quantity Q behind the dam is less than 0.5m ³/s, the grouting ash consumption m _{Ash of ash} is 50-100 t; when the leakage amount of the water body behind the dam is 0.5m ³/s<Q<1m³/s, the grouting ash consumption m _{Ash of ash} is 100-150 t; when the water leakage quantity Q behind the dam is more than 1m ³/s, the grouting ash consumption m _{Ash of ash} is 150-200 t; if yes, the method is reasonable and ended; if not, unreasonably repeating the steps;

In step S4, the calculation formula of the volume V _Pipe is as follows:

V _Pipe ＝1/4×π×d _Pipe ²×L _Pipe (1)

In the formula (1), d _Pipe 、L _Pipe is the diameter and the length of the grouting pipe respectively;

In step S5, the calculation formula of the volume V _{Box (BW)} is as follows:

V _{Box (BW)} ＝B _{Box (BW)} ×L _{Box (BW)} ×H _{Box (BW)} (2)

In the formula (2), L _{Box (BW)} 、B _{Box (BW)} 、H _{Box (BW)} is the length, width and height of the grouting water stop box respectively;

In step S6, the calculation formula of the length L _{Blocking up 1} and the volume V _{Blocking up 1} is as follows:

L _{Blocking up 1}＝K _{Anan (safety)} ρ _{Water and its preparation method} g(H _{Water and its preparation method} -H₀)×π×R _{Blocking up} ²/C'×2π×R _{Blocking up} λ (3)

V _{Blocking up 1}＝π×R _{Blocking up} ²×L _{Blocking up 1} (4)

in the formulas (3) and (4), K _{Anan (safety)} is an anti-slip stable safety coefficient; ρ _{Water and its preparation method} is the density of the water body; h _{Water and its preparation method} 、H₀ is the upstream reservoir Shui Gaocheng and leak path exit elevation, respectively; r _{Blocking up} is the approximate radius of the leak path; c' is the adhesion force of the blocking body; lambda is the effective contact coefficient between the periphery of the main body section of the grouting plugging body and the rock mass;

In step S7, the calculation formula of the length L _{Blocking up 2} and the volume V _{Blocking up 2} is as follows:

L _{Blocking up 2}＝(0.5～0.8)×L _{Blocking up 1} (5)

V _{Blocking up 2}＝1/3×π×R _{Blocking up} ²×L _{Blocking up 2} (6)

In the formulas (5) and (6), L _{Blocking up 1} is the length of the main body section of the grouting plugging body; r _{Blocking up} is the approximate radius of the leak path;

In step S8, the calculation formula of the volume V _{Pores of the material} is as follows:

V _{Pores of the material _i}＝π×r_i ²×l_i (8)

In formulas (7) and (8), N is the number of larger pores directly connected to the leak pipe; r _i is the radius of the ith larger aperture; l _i is the length of the i-th larger aperture; v _{Pores of the material _i} is the volume of slurry filled in the ith larger pore;

In step S9, the calculation formula of the volume V _{Diffusion of} is as follows:

V _{Diffusion of} ＝π×[(R+R _{Blocking up} )²-R _{Blocking up} ²]×L _{Blocking up 1}×n (9)

n＝1-γ_d/Δ_sγ_w (10)

In the formulas (9) and (10), n is the porosity in the rock mass, R is the diffusion radius, and gamma _d、Δ_s、γ_w is the dry volume weight, specific gravity and water volume weight of the rock mass respectively;

In step S10, the calculation formula of the volume V _{Total (S)} is as follows:

V _{Total (S)} ＝K _Pipe V _Pipe +K _{Box (BW)} V _{Box (BW)} +K _{Blocking up 1}V _{Blocking up 1}+K _{Blocking up 2}V _{Blocking up 2}+K _{Diffusion of} V _{Diffusion of} +K _{Pores of the material} V _{Pores of the material} (11)

in the formula (11), K _Pipe 、K _{Box (BW)} 、K _{Blocking up 1}、K _{Blocking up 2}、K _{Diffusion of} 、K _{Pores of the material _i} is the volume safety coefficient corresponding to the volume of the grouting pipeline, the volume of the grouting water stop tank, the volume of the main section of the grouting plugging body, the volume of the auxiliary section of the grouting plugging body, the volume of the grout diffused into the rock micro-cracks, and the volume of the grout filled with larger pores connected with the leakage channel respectively.

2. The method for accurately controlling the grouting filling amount after a dam under the high water head condition according to claim 1, wherein in the step S11, the calculation formula of the grouting ash consumption m _{Ash of ash} is as follows:

m _{Ash of ash} ＝V _{Total (S)} ×ρ _{Secret key} (12)

In formula (12), ρ _{Secret key} is the density of the corresponding cement-to-slurry.