A method for predicting grouting intensity in marine adverse geological reef limestone based on porous structure

Abstract

This invention provides a method for predicting the grouting intensity of marine reef limestone with poor pore structure. The method calculates the pore volume of the reef limestone as a percentage of the total reef limestone volume (the reef limestone rock porosity). It categorizes the equivalent diameter of interconnected pores in the reef limestone by size and calculates the volume ratio of each type of interconnected pore. It calculates the porosity of pore particles using the surface area and volume of the pore particles. Based on the porosity, the pore particles are classified, and the sphericity ratio of each type is calculated. The seepage coefficient is calculated based on the reef limestone porosity, the volume ratio of each type of interconnected pore, and the sphericity ratio of each type of pore particle. The flow rate of the grout under different pressures in the reef limestone is calculated using the seepage coefficient. Finally, the tensile strength of the reef limestone is calculated based on the flow rate before and after grouting. This precise permeability analysis reduces construction risks and costs while improving the bearing capacity of the foundation.

Description

Technical Field

[0001] This invention relates to the field of reef limestone detection technology, specifically to a method for predicting the grouting intensity of marine reef limestone with poor pore structure. Background Technology

[0002] With the growth of global energy demand and the deepening of marine resource development, the stability issues of offshore wind power foundations, cross-sea bridge pile foundations, and offshore oil and gas extraction platforms in marine engineering are becoming increasingly prominent.

[0003] By predicting the compressive strength of grout-reinforced reef limestone, engineers can assess and ensure the foundation stability of marine structures such as offshore platforms, bridges, and docks. This is crucial for preventing structural failure under extreme weather conditions or seabed geological shifts. Accurate compressive strength predictions can help design more effective grouting schemes, optimize material usage, reduce material waste, and shorten construction time. This has a direct impact on reducing project costs and improving construction efficiency. Optimizing grouting reinforcement schemes can also reduce disturbances to the marine environment, such as minimizing chemical leaks during the grouting process and protecting marine ecosystems.

[0004] Reef limestone, a common marine geological material, has a complex pore structure and variable permeability, making traditional grouting methods insufficient to meet the growing engineering demands. Therefore, under adverse marine geological conditions, effectively predicting and improving the grouting strength of reef limestone, and developing a rapid identification and prediction method based on pore structure, is of great significance for improving the safety, economy, and environmental friendliness of marine engineering, and has become an urgent technical problem to be solved in the field of marine engineering. Summary of the Invention

[0005] This invention proposes a method for predicting the grouting strength of marine reef limestone with poor geological conditions based on its porous structure, in order to solve the technical problem of how to effectively predict and improve the grouting strength of reef limestone under poor marine geological conditions.

[0006] To address the aforementioned technical problems, this invention provides a method for predicting the grouting intensity of marine adverse geological reef limestone based on its porous structure, comprising the following steps:

[0007] Step S11: Calculate the porosity value of the reef limestone rock as a percentage of the reef limestone rock mass volume.

[0008] Step S12: Classify the equivalent diameters of connected pores in the reef limestone by size and calculate the volume percentage of each type of connected pore;

[0009] Step S13: Calculate the porosity of the pore particles using the surface area and volume of the pore particles;

[0010] Step S14: Classify the porous particles according to the porosity and calculate the sphericity ratio of each type of porous particle;

[0011] Step S15: Calculate the seepage coefficient based on the porosity value of the reef limestone, the volume ratio of various connected pores, and the sphericity ratio of various pore particles;

[0012] Step S16: Calculate the flow rate of grout in the reef limestone under different pressures using the seepage coefficient; calculate the tensile strength of the reef limestone based on the flow rate before and after grouting.

[0013] Preferably, the expression for step S11 is:

[0014]

[0015] In the formula, P is the porosity value of the reef limestone; V0 is the pore volume of the reef limestone; and V is the volume of the reef limestone.

[0016] Preferably, the expression for step S12 is:

[0017]

[0018] In the formula, E q1 E q2 E q3 E q4 E q5 V1, V2, V3, V4, and V5 represent the pore volumes of small, relatively small, medium, relatively large, and large pores in the reef limestone rock, respectively; V0 represents the pore volume of the reef limestone rock.

[0019] Preferably, the expression for step S13 is:

[0020]

[0021] In the formula, M is the porosity; S is the surface area of ​​the pore particles; and v is the volume of the pore particles.

[0022] Preferably, the expression for step S14 is:

[0023]

[0024] In the formula, N1, N2, N3 and N4 represent the proportions of flat, semi-flat, semi-spherical and spherical pore particles in the porosity of the reef limestone, respectively; M1, M2, M3 and M4 represent the volumes of flat, semi-flat, semi-spherical and spherical pore particles, respectively; and V0 represents the pore volume of the reef limestone.

[0025] Preferably, the expression for step S15 is:

[0026]

[0027] In the formula, K is the seepage coefficient of the reef limestone mass; A, B, C, and D are linear coefficients; P is the porosity value of the reef limestone; α i The proportion of connected pores (E) in the pore volume of reef limestone rocks classified by different equivalent diameters qi- Correction factor; β u N represents the sphericity percentage of various porous particles. u Correction factor; n is the number of particles; R n Let b0 be the pore throat radius of the nth grain within the reef limestone rock; b0 be the initial slip factor; μ T ρ is the dynamic viscosity of the slurry at temperature T; p is the pore pressure; μ0 is the dynamic viscosity of the slurry at the reference temperature; T is the current temperature; T0 is the reference temperature; b is the temperature index.

[0028] Preferably, in step S16, the flow rate Q of the slurry under different pressures in the reef limestone is calculated using the following expression:

[0029]

[0030] In the formula, G is the cross-sectional area of ​​the rock during grouting, k1 is the pressure at the grout inlet, k2 is the pressure at the grout outlet, and L is the distance the grout travels.

[0031] Preferably, in step S16, the expression for calculating the tensile strength of the reef limestone is:

[0032]

[0033] In the formula, Q S Q represents the flow rate of the reef limestone rock after grouting. F The flow rate of the reef limestone before grouting; F S F represents the compressive strength of the reef limestone after grouting. F H represents the compressive strength of the reef limestone before grouting; H is the independent variable coefficient; and J is the intercept.

[0034] Preferably, the pore volume, equivalent diameter of connected pores, pore particle surface area, and pore particle volume of the reef limestone are obtained by the following methods:

[0035] Step S21: After sampling the reef limestone, scan the reef limestone.

[0036] Step S22: Use a threshold segmentation method to segment the pores and solid phase;

[0037] Step S23: Perform 3D reconstruction on the segmented image to generate a 3D model of the soil;

[0038] Step S24: Construct a ball-and-stick model, where the ball represents the porous particles and the stick represents the connectivity between the porous particles.

[0039] Preferably, the scan data of the reef limestone is preprocessed, the preprocessing including noise reduction and contrast enhancement.

[0040] The beneficial effects of this invention include at least the following: In practical marine engineering, such as offshore wind power foundations, the pile foundations of cross-sea bridges, and the stability of offshore oil and gas extraction platforms, an accurate understanding of the permeability of seabed reef limestone is essential. Through the pore structure-based calculation method of this invention, the distribution of grouting materials can be predicted and optimized, improving the stability and durability of the structure. For example, in the construction of offshore wind farms, precise permeability analysis allows for the design of grouting schemes more suitable for local geological conditions, thereby reducing construction risks and costs while improving the load-bearing capacity of the wind power foundation. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the parameter acquisition method according to an embodiment of the present invention. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0044] Example 1

[0045] like Figure 1 As shown in the figure, this invention provides a method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure, including the following steps:

[0046] Step S11: Calculate the porosity value of the reef limestone as a percentage of the volume of the reef limestone mass.

[0047] Specifically, in the grouting process of marine reef limestone with poor geological conditions, the permeability coefficient of the rock can reflect the grout penetration effect during the grouting process, and the permeability coefficient of the rock depends on the pore structure inside the rock mass.

[0048] Porosity values ​​P are used to represent unfavorable geological reef limestone, calculated as the ratio of rock mass porosity to rock mass volume:

[0049]

[0050] In the formula: P is the porosity value of the reef limestone, V0 is the pore volume of the reef limestone, and V is the volume of the reef limestone.

[0051] Step S12: Classify the equivalent diameters of the connected pores in the reef limestone by size and calculate the volume percentage of each type of connected pore.

[0052] Specifically, the reef limestone contains both interconnected and isolated pores. The presence of interconnected pores ensures the injection and flow of grout within the pores, while isolated pores cannot be injected with grout. In this embodiment of the invention, the equivalent diameter E of the interconnected pores in the reef limestone is... q Based on size, they are divided into five categories, including small pores (0 < E). q ≤1mm), small pore size (1mm < E) q ≤2mm), mesopores (2mm < E) q ≤3mm), larger pore size (3mm < E) q ≤4mm), large pores (E q >4mm), then calculate the volume percentage of each type of connected pore.

[0053]

[0054] In the formula: E q1 E q2 E q3 E q4 and E q5 V1, V2, V3, V4, and V5 represent the pore volumes of small, relatively small, medium, relatively large, and large pores in the reef limestone rock, respectively. V0 represents the pore volume of the reef limestone rock.

[0055] Step S13: Calculate the porosity of the pore particles using the surface area and volume of the pore particles.

[0056] Specifically, the porous particles in reef limestone exhibit various shapes. A definition of sphericity is introduced, with a particle shape range of 0-1. 1 represents a perfect sphere, meaning the particle's surface area and volume are identical to a sphere of the same volume. This implies the particle's shape is extremely close to an ideal sphere. 0 represents the particle shape furthest from a sphere, typically extremely flat or elongated particles, such as plate-like or columnar particles. The closer the porous particle shape is to 1, the easier the slurry flows. The calculation expression is:

[0057]

[0058] In the formula: M is the porosity, S is the surface area of ​​the pore particles, and v is the volume of the pore particles.

[0059] Step S14: Classify the porous particles according to their porosity and calculate the sphericity percentage of each type of porous particle.

[0060] Specifically, in this embodiment of the invention, the sphericity of the interconnected pore particles in the reef limestone is classified into flat type (0 < M ≤ 0.25), semi-flat type (0.25 < M ≤ 0.5), semi-spherical type (0.5 < M ≤ 0.75), and spherical type reef limestone (0.75 < M ≤ 1), and the sphericity ratio of each pore particle is calculated.

[0061]

[0062] In the formula: N1, N2, N3 and N4 are the proportions of flat, semi-flat, semi-spherical and spherical pore particles in the porosity of reef limestone, respectively; M1, M2, M3 and M4 are the volumes of flat, semi-flat, semi-spherical and spherical pore particles, respectively; and V0 is the pore volume of reef limestone.

[0063] Step S15: Calculate the seepage coefficient based on the porosity of the reef limestone, the volume ratio of various connected pores, and the sphericity ratio of various pore particles.

[0064] Specifically, the seepage coefficient K of the reef limestone mass is calculated as follows.

[0065]

[0066] In the formula, R n Let α be the pore throat radius of the nth grain within the reef limestone rock, where n is the number of grains; i The proportion of connected pores (E) in the pore volume of reef limestone rocks classified by different equivalent diameters qi- Correction factor; β u N represents the sphericity percentage of various porous particles. u The correction factor; A, B, C, and D are the porosity values ​​P and the volume percentage of each type of connected pore E, respectively. qi The sphericity percentage of various porous particles, M u The linear coefficient of the average pore throat radius within the reef limestone rock; b0 is the initial slip factor; μ T ρ is the dynamic viscosity of the slurry at temperature T; p is the pore pressure, representing the pressure acting on the slurry; μ0 is the dynamic viscosity of the slurry at the reference temperature; T is the current temperature; T0 is the reference temperature, usually 25°C; b is the temperature index.

[0067] Step S16: Calculate the flow rate of grout in the reef limestone under different pressures using the seepage coefficient; calculate the tensile strength of the reef limestone based on the flow rate before and after grouting.

[0068] Specifically, the flow rate of the slurry under different pressures in the reef limestone is calculated using the following expression:

[0069]

[0070] In the formula, G is the cross-sectional area of ​​the rock during grouting, k1 is the pressure at the grout inlet, k2 is the pressure at the grout outlet, and L is the distance the grout travels.

[0071] The greater the grout flow during grouting, the larger the volume of grout remaining within the reef limestone after grouting, indicating a better grouting reinforcement effect and higher rock compressive strength. The compressive strength of the reef limestone after grouting is calculated using the following formula to avoid resampling, prevent rock damage, and reduce disturbance.

[0072]

[0073] In the formula, Q S Q represents the flow rate of the reef limestone rock after grouting. F The flow rate of the reef limestone before grouting; F S F represents the compressive strength of the reef limestone after grouting. F H represents the compressive strength of the reef limestone before grouting; H is the independent variable coefficient; and J is the intercept.

[0074] Example 2

[0075] This embodiment provides a method for acquiring parameters, mainly for obtaining the calculation parameters needed in Embodiment 1.

[0076] Specifically, such as Figure 2 As shown, the main steps include: sampling the marine reef limestone with adverse geological conditions; importing the scanned data, such as CT scans or SEM images, into Avizo software; preprocessing the imported images, including denoising and contrast enhancement, to better distinguish the solid phase and pores of the reef limestone; using a threshold segmentation method to separate the pores and solid phases for subsequent analysis; performing 3D reconstruction on the segmented images to generate a 3D model of the soil; and constructing a ball-and-stick model to represent the reef limestone particles and pores, where the ball represents the particle and the stick represents the connectivity between particles.

[0077] By using the ball-and-stick model to represent and model, the parameters of all the reef limestone rocks required in Example 1 can be obtained.

[0078] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; only preferred embodiments of the present invention are illustrated. The descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. As long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0079] It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure, characterized in that: Includes the following steps: Step S11: Calculate the porosity value of the reef limestone rock as a percentage of the reef limestone rock mass volume. Step S12: Classify the equivalent diameters of connected pores in the reef limestone by size and calculate the volume percentage of each type of connected pore; Step S13: Calculate the porosity of the pore particles using the surface area and volume of the pore particles; Step S14: Classify the porous particles according to the porosity and calculate the sphericity ratio of each type of porous particle; Step S15: Calculate the seepage coefficient based on the porosity value of the reef limestone, the volume ratio of various connected pores, and the sphericity ratio of various pore particles; Step S16: Calculate the flow rate of the slurry under different pressures in the reef limestone using the seepage coefficient; The tensile strength of the reef limestone was calculated based on the flow rates before and after grouting.

2. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 1, characterized in that: The expression for step S11 is: ； In the formula, P is the porosity value of the reef limestone; V0 is the pore volume of the reef limestone; and V is the volume of the reef limestone.

3. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 1, characterized in that: The expression for step S12 is: ； In the formula, E q1 E q2 E q3 E q4 E q5 V1, V2, V3, V4, and V5 represent the pore volumes of small, relatively small, medium, relatively large, and large pores in the reef limestone rock, respectively; V0 represents the pore volume of the reef limestone rock.

4. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 1, characterized in that: The expression for step S13 is: ； In the formula, M is the porosity; S is the surface area of ​​the pore particles; and v is the volume of the pore particles.

5. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 1, characterized in that: The expression for step S14 is: ； In the formula, N1, N2, N3 and N4 represent the proportions of flat, semi-flat, semi-spherical and spherical pore particles in the porosity of the reef limestone, respectively; M1, M2, M3 and M4 represent the volumes of flat, semi-flat, semi-spherical and spherical pore particles, respectively; and V0 represents the pore volume of the reef limestone.

6. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 1, characterized in that: The expression for step S15 is: ； In the formula, K is the seepage coefficient of the reef limestone mass; A, B, C, and D are linear coefficients; P is the porosity value of the reef limestone; α i The proportion of connected pores (E) in the pore volume of reef limestone rocks classified by different equivalent diameters qi Correction factor; β u N represents the sphericity percentage of various porous particles. u Correction factor; n is the number of particles; R n Let b0 be the pore throat radius of the nth grain within the reef limestone rock; b0 be the initial slip factor; μ T ρ is the dynamic viscosity of the slurry at temperature T; p is the pore pressure; μ0 is the dynamic viscosity of the slurry at the reference temperature; T is the current temperature; T0 is the reference temperature; b is the temperature index.

7. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 6, characterized in that: In step S16, the flow rate of the slurry under different pressures in the reef limestone is calculated using the following expression. : ； In the formula, G is the cross-sectional area of ​​the rock during grouting, k1 is the pressure at the grout inlet, k2 is the pressure at the grout outlet, and L is the distance the grout travels.

8. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 7, characterized in that: In step S16, the expression for calculating the tensile strength of the reef limestone is: ； In the formula, Q S Q represents the flow rate of the reef limestone rock after grouting. F F represents the flow rate of the reef limestone rock before grouting. S F represents the compressive strength of the reef limestone after grouting. F H represents the compressive strength of the reef limestone before grouting; H is the independent variable coefficient; and J is the intercept.

9. The method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 1, characterized in that: The pore volume, equivalent diameter of connected pores, pore particle surface area, and pore particle volume of the reef limestone were obtained by the following methods: Step S21: After sampling the reef limestone, scan the reef limestone. Step S22: Use a threshold segmentation method to segment the pores and solid phase; Step S23: Perform 3D reconstruction on the segmented image to generate a 3D model of the soil; Step S24: Construct a ball-and-stick model, where the ball represents the porous particles and the stick represents the connectivity between the porous particles.

10. A method for predicting the grouting intensity of marine adverse geological reef limestone based on porous structure according to claim 9, characterized in that: The scan data of the reef limestone are preprocessed, including noise reduction and contrast enhancement.

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