Deep surrounding rock-fluidized medium collaborative bearing mechanical model construction method

Abstract

The invention discloses a deep surrounding rock-fluidized medium collaborative bearing capacity mechanical model construction method which comprises the following steps: S1, constructing a surrounding rock nonlinear strength model: based on a generalized Hoek-Brown criterion, introducing a confining pressure-plastic shear strain negative exponential function relationship, and establishing a deep surrounding rock nonlinear strength criterion considering a post-peak softening characteristic; and S2, establishing a fluidization medium constitutive model, wherein the viscoelastic parameters of the grouting body are obtained through an indoor rheological test. The invention relates to the field of underground engineering mechanics. According to the deep surrounding rock-fluidized medium collaborative bearing mechanical model construction method, by establishing a mechanical model considering the surrounding rock post-peak softening characteristic, the fluidized medium rheological characteristic and the interface nonlinear behavior, the mechanical behavior in the deep surrounding rock-fluidized medium collaborative bearing process can be described more accurately, and compared with a traditional model, the construction method has the advantages that the construction efficiency is improved, and the construction cost is reduced. The accuracy and reliability of a calculation result are greatly improved, and a more reliable theoretical basis is provided for stability analysis of deep underground engineering.

Description

Technical Field

[0001] This invention relates to the field of underground engineering mechanics, specifically to a method for constructing a collaborative bearing mechanics model of deep surrounding rock and fluidized medium. Background Technology

[0002] In the process of deep underground engineering construction and resource extraction, as the mining depth continues to increase, the deep surrounding rock is in a complex environment of high ground stress, high osmotic pressure and high temperature. Its mechanical behavior exhibits significant nonlinearity, discontinuity and time correlation. Traditional surrounding rock mechanics models are difficult to accurately describe the deformation and failure process of deep surrounding rock under complex conditions. In particular, when the surrounding rock undergoes fluidization, the interaction between the surrounding rock and the fluidized medium makes the mechanical behavior more complex. Existing research has several shortcomings in constructing mechanical models for the collaborative bearing capacity of deep surrounding rock and fluidized media. For example, the description of the strength characteristics of the surrounding rock does not fully consider the post-peak softening process; the constitutive relationship of the fluidized media is not accurately described, failing to adequately reflect its rheological properties such as shear thinning; and when dealing with the contact interface between the surrounding rock and the fluidized media, there is a lack of effective theories and methods to describe the nonlinear behavior and damage evolution process of the interface. Furthermore, existing numerical calculation methods and platforms are difficult to implement multi-physics coupling analysis in simulating the collaborative bearing capacity of deep surrounding rock and fluidized media, failing to meet the actual needs of complex working conditions in deep underground engineering. Therefore, this invention provides a method for constructing a mechanical model for the collaborative bearing capacity of deep surrounding rock and fluidized media. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for constructing a collaborative bearing mechanics model of deep surrounding rock and fluidized medium. This method solves the problem that traditional surrounding rock mechanics models are unable to accurately describe the deformation and failure process of deep surrounding rock under complex conditions in deep underground engineering, especially the complex mechanical behavior when the surrounding rock interacts with the fluidized medium. This includes the existing models' insufficient description of the softening of the surrounding rock after the peak, the rheological properties of the fluidized medium, and the nonlinear behavior of the interface, as well as the difficulty of numerical calculation methods and platforms in realizing multi-physics coupling analysis.

[0004] To achieve the above objectives, the present invention provides a method for constructing a collaborative bearing capacity mechanical model of deep surrounding rock and fluidized medium, comprising the following steps: S1. Constructing a nonlinear strength model for surrounding rock: Based on the generalized Hoek-Brown criterion, a negative exponential function relationship between confining pressure and plastic shear strain is introduced to establish a nonlinear strength criterion for deep surrounding rock that considers post-peak softening characteristics. S2. Establish constitutive model of fluidized medium: obtain viscoelastic parameters of grout body through indoor rheological tests, and describe its shear thinning characteristics in combination with Bingham fluid model; S3. Define the nonlinear contact interface: Based on fractal geometry theory, establish the roughness-bond strength relationship of the surrounding rock-medium interface, and introduce a damage factor to describe the interface debonding process. S4. Construct a collaborative bearing mechanics model: Treat the surrounding rock, fluidized medium and interface as a unified system, and solve the stress-strain field distribution through an elastoplastic contact iterative algorithm; S5. Develop a numerical computing platform: Based on the ABAQUS / UMAT interface, realize model parameterization input and dynamic simulation.

[0005] Preferably, the nonlinear strength model of the surrounding rock satisfies:

[0006] in, , Principal stress, The uniaxial compressive strength of intact rock. , The rock mass integrity coefficient. The softening coefficient is... This refers to plastic shear strain.

[0007] Preferably, the constitutive model of the fluidized medium satisfies:

[0008] in, For shear stress, For yield stress, To achieve plastic viscosity, Shear rate, , These are rheological parameters.

[0009] Preferably, the contact nonlinear interface satisfies:

[0010] in, For the interfacial shear strength, , For interfacial cohesion and friction angle, For damage factors, 0 ≤ ≤1.

[0011] Preferably, the elastoplastic contact iterative algorithm includes: initial stress field assignment, determination of plastic zone expansion in surrounding rock, updating of medium rheological displacement, iterative solution of interface contact force, and convergence criterion.

[0012] in, For the maximum contact force increment, For maximum contact force, For convergence accuracy.

[0013] Preferably, the numerical computation platform supports multiphysics coupling, including: a. Thermo-mechanical coupling: Considering the influence of the temperature field on the curing of the medium during the grouting process; b. Seepage-stress coupling: Based on Biot theory, this describes the weakening effect of pore water pressure on the effective stress of the surrounding rock.

[0014] Preferably, the model parameter calibration is obtained through the following experiments: c. Surrounding rock: Uniaxial compressive strength test, triaxial compression test, Brazilian splitting test; d. Medium: Wave velocity test, rheometer shear test, curing time-strength curve test; e. Interface: Direct shear test, laser scanning roughness measurement, structural surface observation, borehole RQD measurement.

[0015] Preferably, the model is applicable to deep engineering projects with a burial depth ≥ 800m and a ground stress ≥ 20MPa, and the fluidized medium has a curing time ≤ 24h and a compressive strength ≥ 5MPa.

[0016] Beneficial effects This invention provides a method for constructing a collaborative bearing capacity mechanical model of deep surrounding rock and fluidized medium. Compared with existing technologies, it has the following advantages: 1. The proposed method for constructing a mechanical model for the coordinated bearing capacity of deep surrounding rock and fluidized medium, by establishing a mechanical model that considers the softening characteristics of the surrounding rock after the peak, the rheological characteristics of the fluidized medium, and the nonlinear behavior of the interface, can more accurately describe the mechanical behavior in the coordinated bearing capacity process of deep surrounding rock and fluidized medium. Compared with traditional models, it greatly improves the accuracy and reliability of the calculation results and provides a more reliable theoretical basis for the stability analysis of deep underground engineering.

[0017] 2. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model supports multi-physics coupling analysis, such as thermo-mechanical coupling and seepage-stress coupling, through a numerical calculation platform based on the ABAQUS / UMAT interface. This method can realistically simulate complex physical processes in deep underground engineering, such as the influence of temperature changes on medium solidification during grouting and the influence of groundwater seepage on the stress state of the surrounding rock. This makes the simulation results more consistent with actual engineering conditions and provides more comprehensive technical support for engineering design and construction.

[0018] 3. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model is applicable to deep engineering projects under specific conditions (burial depth ≥ 800m, ground stress ≥ 20MPa, fluidized medium solidification time ≤ 24h, compressive strength ≥ 5MPa). It can accurately analyze the characteristics of such projects, has strong practicality, and helps to improve the scientific nature of deep underground engineering design and construction, reduce engineering risks, and save engineering costs. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the operation of the method for constructing a collaborative bearing mechanics model of deep surrounding rock and fluidized medium according to the present invention. Detailed Implementation

[0020] 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 scope of protection of the present invention.

[0021] Please see Figure 1 The present invention provides a technical solution: A method for constructing a collaborative bearing capacity mechanical model of deep surrounding rock and fluidized medium includes the following steps: S1. Constructing a nonlinear strength model for surrounding rock: Based on the generalized Hoek-Brown criterion, a negative exponential function relationship between confining pressure and plastic shear strain is introduced to establish a nonlinear strength criterion for deep surrounding rock that considers post-peak softening characteristics. This criterion can more accurately describe the strength changes of deep surrounding rocks under complex stress states, especially the softening behavior in the post-peak stage, providing a more reliable theoretical basis for analyzing the deformation and failure of surrounding rocks.

[0022] S2. Establish constitutive model of fluidized medium: obtain viscoelastic parameters of grout body through indoor rheological tests, and describe its shear thinning characteristics in combination with Bingham fluid model; This constitutive model can accurately reflect the mechanical response of fluidized media at different shear rates, providing a reasonable mathematical description for simulating the flow and load-bearing process of fluidized media.

[0023] S3. Define the nonlinear contact interface: Based on fractal geometry theory, establish the roughness-bond strength relationship of the surrounding rock-medium interface, and introduce a damage factor to describe the interface debonding process. This method can effectively take into account the nonlinear behavior and damage evolution of the interface, and accurately simulate the interaction process between the surrounding rock and the fluidized medium.

[0024] S4. Construct a collaborative bearing mechanics model: Treat the surrounding rock, fluidized medium and interface as a unified system, and solve the stress-strain field distribution through an elastoplastic contact iterative algorithm; This algorithm can comprehensively consider the mechanical properties of the surrounding rock, fluidized medium and interface, and achieve accurate calculation of the mechanical behavior of the entire cooperative bearing system.

[0025] S5. Develop a numerical computing platform: Based on the ABAQUS / UMAT interface, realize model parameterization input and dynamic simulation.

[0026] This numerical computing platform supports multi-physics coupling, including thermo-mechanical coupling, which is used to consider the influence of the temperature field on the solidification of the medium during the grouting process; and seepage-stress coupling, which describes the weakening effect of pore water pressure on the effective stress of the surrounding rock based on Biot theory, thereby enabling more realistic simulation of the complex working conditions of deep underground engineering.

[0027] In this embodiment of the invention, the nonlinear strength model of the surrounding rock satisfies:

[0028] in, , Principal stress, The uniaxial compressive strength of intact rock. , The rock mass integrity coefficient. The softening coefficient is... This refers to plastic shear strain.

[0029] Where s reflects the degree of rock mass fragmentation (value range 0 to 1). This is a parameter for correcting the curvature of the strength envelope; the rock mass integrity coefficient refers to the value in the Hoek-Brown criterion. , Parameters are used to quantify the degree of rock mass fragmentation and structural features.

[0030] In this embodiment of the invention, the constitutive model of the fluidized medium satisfies:

[0031] in, For shear stress, For yield stress, To achieve plastic viscosity, Shear rate, , These are rheological parameters.

[0032] In this embodiment of the invention, the contact nonlinear interface satisfies:

[0033] in, For the interfacial shear strength, , For interfacial cohesion and friction angle, For damage factors, 0 ≤ ≤1.

[0034] In this embodiment of the invention, the elastoplastic contact iterative algorithm includes: initial stress field assignment, determination of plastic zone expansion in surrounding rock, updating of medium rheological displacement, iterative solution of interface contact force, and convergence criterion.

[0035] in, For the maximum contact force increment, For maximum contact force, For convergence accuracy.

[0036] In this embodiment of the invention, the numerical computation platform supports multiphysics coupling, including: a. Thermo-mechanical coupling: Considering the influence of the temperature field on the curing of the medium during the grouting process; b. Seepage-stress coupling: Based on Biot theory, this describes the weakening effect of pore water pressure on the effective stress of the surrounding rock.

[0037] By establishing the relationship between temperature and the mechanical properties of the medium, thermo-mechanical coupling analysis is achieved, which accurately simulates the changes in the mechanical properties of the medium during the grouting process. By establishing the coupling relationship between the seepage equation and the stress equation, seepage-stress coupling analysis is achieved, taking into account the influence of groundwater on the stability of the surrounding rock.

[0038] In this embodiment of the invention, the model parameters need to be calibrated through the following experiments: c. Surrounding rock: Uniaxial compressive strength test, triaxial compression test, Brazilian splitting test; d. Medium: Wave velocity test, rheometer shear test, curing time-strength curve test; e. Interface: Direct shear test, laser scanning roughness measurement, structural surface observation, borehole RQD measurement.

[0039] Triaxial compression tests and Brazilian splitting tests were conducted to obtain the mechanical parameters of the surrounding rock, such as elastic modulus, Poisson's ratio, compressive strength, and tensile strength, which were used to determine the parameters in the nonlinear strength model of the surrounding rock. Rheometer shear tests and curing time-strength curve tests were conducted to obtain the viscoelastic parameters, yield stress, plastic viscosity, etc. of the fluidized medium, as well as the change law of strength with time during the curing process of the medium, which were used to establish a constitutive model of the fluidized medium. Direct shear tests and laser scanning roughness measurements were conducted to obtain parameters such as interface cohesion, friction angle, and roughness, which were used to define the nonlinear contact interface.

[0040] In this embodiment of the invention, the model is applicable to deep engineering projects with a burial depth ≥ 800m and a ground stress ≥ 20MPa, and the solidification time of the fluidized medium is ≤ 24h and the compressive strength is ≥ 5MPa.

[0041] In summary: By establishing a mechanical model that considers the softening characteristics of the surrounding rock after the peak, the rheological characteristics of the fluidized medium, and the nonlinear behavior of the interface, and developing a corresponding numerical calculation platform, we can achieve accurate simulation of the collaborative bearing process of deep surrounding rock and fluidized medium, providing more accurate and effective theoretical tools and technical means for stability analysis and support design of deep underground engineering.

[0042] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for constructing a collaborative bearing capacity mechanical model of deep surrounding rock and fluidized medium, characterized in that, Includes the following steps: S1. Constructing a nonlinear strength model for surrounding rock: Based on the generalized Hoek-Brown criterion, a negative exponential function relationship between confining pressure and plastic shear strain is introduced to establish a nonlinear strength criterion for deep surrounding rock that considers post-peak softening characteristics. S2. Establish constitutive model of fluidized medium: obtain viscoelastic parameters of grout body through indoor rheological tests, and describe its shear thinning characteristics in combination with Bingham fluid model; S3. Define the nonlinear contact interface: Based on fractal geometry theory, establish the roughness-bond strength relationship of the surrounding rock-medium interface, and introduce a damage factor to describe the interface debonding process. S4. Construct a collaborative bearing mechanics model: Treat the surrounding rock, fluidized medium and interface as a unified system, and solve the stress-strain field distribution through an elastoplastic contact iterative algorithm; S5. Develop a numerical computing platform: Based on the ABAQUS / UMAT interface, realize model parameterization input and dynamic simulation.

2. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model according to claim 1, characterized in that: The nonlinear strength model of the surrounding rock satisfies: ； in, , Principal stress, The uniaxial compressive strength of intact rock. , The rock mass integrity coefficient. The softening coefficient is... This refers to plastic shear strain.

3. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model according to claim 1, characterized in that: The constitutive model of the fluidized medium satisfies: ； in, For shear stress, For yield stress, To achieve plastic viscosity, For shear rate, , These are rheological parameters.

4. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model according to claim 1, characterized in that: The contact nonlinear interface satisfies: ； in, For the interfacial shear strength, , For interfacial cohesion and friction angle, For damage factors, 0 ≤ ≤1.

5. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model according to claim 1, characterized in that: The elastoplastic contact iterative algorithm includes: initial stress field assignment, determination of plastic zone expansion in surrounding rock, updating of medium rheological displacement, iterative solution of interface contact force, and convergence criterion. ； in, For the maximum contact force increment, For maximum contact force, For convergence accuracy.

6. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model according to claim 1, characterized in that: The numerical computation platform supports multiphysics coupling, including: a. Thermo-mechanical coupling: Considering the influence of the temperature field on the curing of the medium during the grouting process; b. Seepage-stress coupling: Based on Biot theory, this describes the weakening effect of pore water pressure on the effective stress of the surrounding rock.

7. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model according to claim 1, characterized in that: The model parameters need to be calibrated through the following experiments: c. Surrounding rock: Uniaxial compressive strength test, triaxial compression test, Brazilian splitting test; d. Medium: Wave velocity test, rheometer shear test, curing time-strength curve test; e. Interface: Direct shear test, laser scanning roughness measurement, structural surface observation, borehole RQD measurement.

8. The method for constructing a deep surrounding rock-fluidized medium co-bearing mechanical model according to claim 1, characterized in that: The model is applicable to deep engineering projects with a burial depth ≥ 800m and ground stress ≥ 20MPa, and the fluidized medium has a curing time ≤ 24h and a compressive strength ≥ 5MPa.

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