Dam abutment three-dimensional block stability analysis method based on 3DE

Abstract

The invention discloses a dam abutment three-dimensional block stability analysis method based on 3DE. The method comprises the following steps: constructing a three-dimensional geologic model in a dam abutment area in 3DE; dividing the three-dimensional block body of the dam abutment into discrete block bodies according to the spatial cutting relation of the structural surfaces; the direction of the intersecting line between the side sliding surface and the bottom sliding surface is defined as the possible sliding direction of the dam abutment three-dimensional block; taking the mass center of each discrete block as a starting point, and drawing a vector along the action direction of each type of load; obtaining resultant force vectors of the corresponding discrete blocks in an absolute coordinate system; determining possible sliding force borne by the dam abutment three-dimensional block and normal force of each sliding surface; the possible anti-sliding force borne by the dam abutment three-dimensional block is obtained. According to the method, the block morphology and the load distribution are visually displayed in a three-dimensional form, the possible sliding direction, the possible sliding force and the possible anti-sliding force of the three-dimensional block of the dam abutment can be automatically determined, the calculation efficiency is improved, and the accuracy of a calculation result is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of water conservancy and hydropower engineering, and in particular to a 3DE-based three-dimensional block stability analysis method for a dam abutment. Background Art

[0002] In water conservancy and hydropower projects, dam abutment stability refers to the stability of the rock or soil at the junction of the dam and the mountain (i.e., the abutment) under the effects of natural forces and engineering loads. Arch and gravity dams are primarily analyzed. Dam abutment stability is directly related to dam operational safety. If the abutment fails, it can lead to structural damage, dam failure, and subsequent reservoir water release, with devastating consequences for downstream areas.

[0003] Abutment stability analysis requires clarifying the possible sliding direction, sliding force, and anti-sliding force of the block. This involves two key technical issues: determining the load acting on the block and performing load spatial decomposition. The loads acting on the block primarily include deadweight, hydrostatic pressure, uplift pressure, and seismic inertia. Load spatial decomposition involves decomposing the load acting on the block based on the sliding direction and the normal to the sliding surface to determine the specific values of the sliding force and anti-sliding force.

[0004] In the prior art, the load on a block is generally determined by manual calculation or drawing a force graph to obtain the force magnitude, which is then used as input for stability analysis. However, this method has the following technical problems:

[0005] First, it is inefficient. The process of drawing the three-dimensional block force diagram is cumbersome. Once the boundary conditions such as the water level and the anti-seepage curtain design scheme change, the calculation needs to be re-performed, which is time-consuming and labor-intensive.

[0006] Second, it is not intuitive enough. The manual calculation and drawing methods lack visual support, making it difficult to intuitively display the load distribution, which is not conducive to the judgment and decision-making of engineers.

[0007] In existing technologies, the process of load space decomposition usually relies on programming. By formulating calculation rules, the occurrence (i.e., strike, dip, and inclination) of each structural surface of the block is identified and converted. However, there are the following technical problems:

[0008] First, the programming complexity is high. The programming implementation of load space decomposition requires the formulation of complex calculation rules, which is difficult to develop and is prone to errors due to improper rule design.

[0009] Second, the calculation results are prone to errors. The structural surface attitude has different definition methods (such as the difference between the geological coordinate system and the mathematical coordinate system). In programming implementation, inconsistent definition methods or conversion errors can easily lead to inaccurate decomposition results.

[0010] Third, there is a lack of verifiability. The definition and calculation process of the structural surface attitude are encapsulated in a black box and lack of visual display, making it difficult to judge the reliability of the analysis results. Summary of the Invention

[0011] In response to the shortcomings of the existing technology, the present invention proposes a 3DE-based three-dimensional block stability analysis method for the dam abutment. The method can not only automatically calculate and intuitively display the magnitude and direction of various types of loads and the magnitude and direction of the resultant force applied to each discrete block according to changes in the water level and anti-seepage curtain design scheme; it can also automatically determine the possible sliding direction of the three-dimensional blocks of the dam abutment, and automatically perform load space decomposition on the platform to determine the possible sliding force and possible anti-sliding force of the three-dimensional blocks of the dam abutment, thereby improving the calculation efficiency and ensuring the accuracy of the calculation results.

[0012] To achieve the above objectives, the present invention designs a 3D block stability analysis method for dam abutments based on 3DE, which is particularly characterized by comprising the following steps:

[0013] S1) constructing a three-dimensional geological model of the dam abutment area in 3DE, wherein the three-dimensional geological model includes lithology distribution and structural surface characteristics;

[0014] S2) Based on the 3D geological model, the 3D block of the dam abutment is divided into discrete blocks through the spatial cutting relationship of the structural surface;

[0015] S3) Extract each structural surface of each discrete block in 3DE, and define the side slip surface, bottom slip surface, upstream tensile fracture surface and free surface in each structural surface, and define the intersection direction between the side slip surface and the bottom slip surface as the possible sliding direction of the 3D block of the dam abutment;

[0016] S4) obtaining the centroid of each discrete block and establishing an absolute coordinate system at each centroid; inputting parameters into the 3DE and automatically calculating various types of loads on each discrete block by editing formulas;

[0017] Starting from the centroid of each discrete block, vectors are drawn along the direction of each type of load, and the length of the vector represents the load value, thereby achieving an intuitive display of the magnitude and direction of each type of load;

[0018] S5) superimposing and calculating the load vectors of each type acting on each discrete block to obtain the resultant force vector acting on the corresponding discrete block in the absolute coordinate system;

[0019] S6) establishing a local coordinate system at each mass point, with the Z' direction in the local coordinate system being consistent with the possible sliding direction defined in step S3), decomposing the resultant force vector acting on each discrete block in step S5) and projecting it into the Z' direction and the X'Y' plane, then performing a secondary decomposition on the resultant force components in the X'Y' plane and projecting them onto the normals of the sideslip surface and the bottom slip surface, respectively, where the resultant force component in the Z' direction is the possible sliding force acting on the three-dimensional block of the dam abutment, and the resultant force components in the normal directions of the sideslip surface and the bottom slip surface are the normal forces acting on each sliding surface on the three-dimensional block of the dam abutment;

[0020] S7) The cohesive force and internal friction angle of the side and bottom sliding surfaces are used as input parameters in the 3DE. According to the formula of anti-slip force = normal force of each sliding surface * friction coefficient + area of each sliding surface * cohesive force, the possible anti-slip force on the three-dimensional block of the dam abutment is calculated.

[0021] Furthermore, in S1), constructing a three-dimensional geological model includes the following steps: importing the original landform in the dam shoulder area into 3DE, and establishing a three-dimensional terrain model after the project implementation in combination with the dam shoulder excavation plan; based on the three-dimensional terrain model, importing the spatial distribution information of rock interfaces, faults, and joints, thereby realizing the construction of a three-dimensional geological model.

[0022] Furthermore, in S2), the step of dividing the three-dimensional block of the dam abutment into discrete blocks includes automatically identifying potential unstable blocks through the block theory algorithm in 3DE, and dividing the potential unstable blocks into discrete blocks through the spatial cutting relationship of the structural surface.

[0023] Furthermore, in S3), before extracting each structural surface of each discrete block, it is necessary to intuitively display the spatial position of each discrete block through 3DE and determine the properties of each structural surface of each discrete block.

[0024] Furthermore, in S4), the centroid of each discrete block is obtained based on the measurement function of 3DE, and the X, Y, and Z directions in the absolute coordinate system are determined to correspond to the downstream direction, cross-river direction, and vertical direction in the project, respectively.

[0025] Furthermore, in S4), the various types of loads on each discrete block include gravity, hydrostatic pressure, uplift pressure, seismic inertia force, and arch end force.

[0026] Furthermore, in S4), for the gravity calculation of each discrete block, it is necessary to obtain the volume of each discrete block based on the measurement function of 3DE, define the density of each discrete block as an input parameter, and edit the formula to automatically obtain the block gravity.

[0027] Furthermore, in S5), the step of superimposing and calculating each type of load vector borne by each discrete block includes projecting each type of load vector in the X, Y, and Z directions of the corresponding absolute coordinate system, and superimposing and calculating the components of all types of load vectors, thereby obtaining a resultant force vector representing the corresponding discrete block in the absolute coordinate system.

[0028] Furthermore, in S7), the anti-sliding stability safety factor of the three-dimensional blocks of the dam abutment is obtained according to the anti-sliding stability safety factor = anti-sliding force / sliding force, and the stability of the three-dimensional blocks of the dam abutment is determined by comparing the anti-sliding stability safety factor with the minimum safety factor.

[0029] The advantages of the present invention are:

[0030] 1. Strong visualization support: Based on 3DE technology, this invention intuitively displays block morphology and load distribution in three dimensions, and supports dynamic adjustment of viewing angle and zoom ratio, making it easier for engineers to quickly understand the stress state and analysis results of the 3D blocks of the dam abutment.

[0031] 2. Rapid response to changes in boundary conditions: Based on the 3DE parameterization function, the present invention sets water level, curtain range, uplift pressure reduction coefficient, cohesion, internal friction angle, etc. as input parameters. Once the boundary conditions such as water level and curtain design scheme change, the system can quickly recalculate to meet the needs of multi-condition analysis;

[0032] 3. Significantly improve analysis efficiency and accuracy: This invention uses 3DE technology to achieve unstable block identification, load calculation, and stability analysis, significantly reducing manual intervention and calculation time. The three-dimensional geological model constructed based on 3DE technology can accurately reflect the spatial distribution of rock masses, faults, joints and other geological characteristics, avoiding the errors of traditional two-dimensional simplified methods.

[0033] 4. Seamless integration with 3D forward design: Based on a 3DE platform, this invention can directly utilize data such as terrain, geology, dam, and excavation plans generated during the 3D forward design process, enabling seamless integration and sharing of 3D forward design data. Simultaneously, based on stability analysis results, designers can dynamically adjust design parameters such as the dam abutment excavation plan and anti-seepage curtain layout, achieving closed-loop optimization of design and analysis. Furthermore, the generated stability analysis results can be directly integrated with the digital delivery standards of 3D forward design, meeting the requirements of digital engineering delivery.

[0034] 5. This method defines the intersection direction between the side sliding surface and the bottom sliding surface as the possible sliding direction of the three-dimensional blocks of the dam abutment. It intuitively represents the various types of loads and resultant force vectors acting on each discrete block in an absolute coordinate system, and performs spatial decomposition and calculation of possible sliding forces and possible anti-sliding forces in a local coordinate system. This method is simple to calculate, error-prone, and verifiable.

[0035] 6. Promote technological progress: This invention combines 3DE technology with block theory algorithms to propose a new dam abutment three-dimensional block stability analysis method, which has strong standardization and scalability and can be applied to other rock stability analysis fields (such as slope stability analysis, underground engineering stability analysis, etc.).

[0036] The 3DE-based three-dimensional block stability analysis method for dam abutments of the present invention can, on the one hand, intuitively display the block morphology and load distribution in three-dimensional form according to changes in water level and anti-seepage curtain design scheme, and support dynamic adjustment of viewing angle and scaling ratio; on the other hand, it can automatically determine the possible sliding direction of the three-dimensional blocks of the dam abutment, and automatically perform load space decomposition on the platform to determine the possible sliding force and possible anti-sliding force of the three-dimensional blocks of the dam abutment; the present invention overcomes the limitations of traditional methods through an efficient, accurate and visual analysis method, improves calculation efficiency, ensures the accuracy of calculation results, and promotes technological progress in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of the present invention;

[0038] Figure 2 Schematic diagram of the spatial cutting relationship of the three-dimensional blocks of the dam abutment in an embodiment of the present invention;

[0039] Figures 3a to 3c Schematic diagrams of the three-dimensional blocks of the dam abutment in each surface in an embodiment of the present invention;

[0040] Figure 4 This is the design parameter interface input on the 3DE platform in the embodiment of the present invention;

[0041] Figure 5 Schematic diagram of the three-dimensional hydrostatic pressure and uplift pressure of the three-dimensional block of the dam abutment in an embodiment of the present invention;

[0042] Figure 6 Schematic diagram of the spatial decomposition of the load acting on one of the discrete blocks in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] like Figure 1 As shown, the present invention provides a 3D block stability analysis method for a dam abutment based on 3DE, comprising the following steps:

[0045] S1) Constructing a three-dimensional geological model of the dam abutment area in 3DE, wherein the three-dimensional geological model includes lithology distribution and structural surface characteristics.

[0046] Specifically, constructing a three-dimensional geological model includes the following steps: importing the original landform in the dam abutment area into 3DE, and establishing a three-dimensional terrain model after the project implementation in combination with the dam abutment excavation plan; based on the three-dimensional terrain model, importing the spatial distribution information of lithologic interfaces, faults, and joints, and utilizing the three-dimensional modeling function of 3DE to realize the construction of a three-dimensional geological model.

[0047] S2) Based on the 3D geological model, the 3D block of the dam abutment is divided into discrete blocks through the spatial cutting relationship of the structural surface.

[0048] Specifically, the steps of dividing the three-dimensional block of the dam abutment into discrete blocks include automatically identifying potential unstable blocks through the block theory algorithm in 3DE, and dividing the potential unstable blocks into discrete blocks through the spatial cutting relationship of the structural surface.

[0049] like Figure 2 The figure shows the spatial cutting relationship of the three-dimensional blocks of the dam abutment in this embodiment. Figure 2 In the figure, the fault plane, gently dipping crack plane and dam heel tangent plane downstream of the left dam abutment combine to form a typical sliding block on the left bank.

[0050] S3) Extract the structural surfaces of each discrete block in 3DE, and define the side slip surface, bottom slip surface, upstream tensile fracture surface, and free surface in each structural surface. The intersection direction between the side slip surface and the bottom slip surface is defined as the possible sliding direction of the 3D block of the dam abutment.

[0051] Specifically, before extracting each structural surface of each discrete block, it is necessary to visually display the spatial position of each discrete block through 3DE and determine the properties of each structural surface of each discrete block. In this embodiment, the properties of each structural surface of the discrete block are determined manually.

[0052] In this embodiment, various surfaces are extracted from 3DE, and the fault surface, gently inclined crack surface, dam heel tangent surface, and downstream bank slope are defined as the side slip surface, bottom slip surface, upstream tensile fracture surface, and free surface, respectively, as shown in FIG3 .

[0053] Generally, the upstream water level is much higher than the downstream water level, and the arch end thrust tends to be downstream, so the sliding direction may point downstream along the intersection line.

[0054] S4) obtaining the centroid of each discrete block and establishing an absolute coordinate system at each centroid; inputting parameters into the 3DE and automatically calculating various types of loads on each discrete block by editing formulas;

[0055] Starting from the centroid of each discrete block, vectors are drawn along the direction of each type of load, and the length of the vector represents the numerical value of the load, thereby achieving an intuitive display of the magnitude and direction of each type of load.

[0056] Specifically, the centroid of each discrete block is obtained based on the measurement function of 3DE, and the X, Y, and Z directions in the absolute coordinate system are determined to correspond to the downstream, cross-river, and vertical directions in the project, respectively.

[0057] Specifically, the various types of loads on each discrete block include gravity, hydrostatic pressure, uplift pressure, seismic inertia force, and arch end force.

[0058] For the gravity calculation of each discrete block, it is necessary to automatically obtain the volume of each discrete block based on the measurement function of 3DE and define the density of each discrete block as an input parameter (see Figure 4 The rock mass density in the design parameter input interface is used to automatically calculate the block gravity by editing formula (1). When the discrete block shape changes, 3DE can automatically update the volume measurement results; when the discrete block density changes, the results can be updated by adjusting the input parameters.

[0059] Formula (1) is as follows:

[0060] G=ρ 岩 gV (1)

[0061] Where,

[0062] G represents the gravity of each discrete block,

[0063] ρ 岩 represents the density of each discrete block,

[0064] g represents the acceleration due to gravity, which is 10N / kg.

[0065] V represents the volume of each discrete block.

[0066] In this embodiment, the volume of the typical left bank slider V = 164.74 × 10 4 m 3 , for this project ρ 岩 2250kg / m 3 , edit formula (1) to automatically obtain the block weight G = 10N / kg × 2250kg / m 3 ×164.739×10 4 m 3 =3.71×10 4 MN.

[0067] For the calculation of hydrostatic pressure of each discrete block, define the upstream water level H 上 , downstream water level H 下 For input parameters (see Figure 4The upstream water level and downstream water level in the design parameter input interface are used to establish the corresponding elevation plane, and the intersection points between the upstream water level plane and the crack surface, and the downstream water level plane and the free surface are extracted respectively. The hydrostatic pressure at the intersection point is 0. The hydrostatic pressure at each point is automatically calculated by editing formulas (2) and (3). A vector is drawn along the hydrostatic pressure direction at each point (the length of the vector represents the hydrostatic pressure value), and these are connected in sequence to form a three-dimensional hydrostatic pressure graph. Figure 5 As shown, the volume is measured to obtain the hydrostatic pressure on the fracture surface and the free surface. For the normal water storage level, design flood level, verification flood level and other working conditions of the project, the calculation results under different working conditions can be obtained by adjusting the input parameters.

[0068] Formulas (2) and (3) are as follows:

[0069] Upstream point hydrostatic pressure: P 静 =ρ 水 g(H 上 -H i ) (2)

[0070] Downstream point hydrostatic pressure: P 静 =ρ 水 g(H 下 -H i ) (3)

[0071] Where:

[0072] P 静 represents the hydrostatic pressure at each point,

[0073] ρ 水 represents the density of water,

[0074] g represents the acceleration due to gravity, which is 10N / kg.

[0075] H 上 Indicates the upstream water level,

[0076] H 下 Indicates the downstream water level,

[0077] H i Indicates the elevation of each point, which is the Z coordinate of each point.

[0078] i is the number of each point, which can be named in 3DE according to actual conditions.

[0079] For this embodiment, taking the normal water level + design earthquake condition as an example, H 上 =565m, H 下 = 496m. Calculate the hydrostatic pressure P on the upstream fracture surface 静上 =9.39×10 3 MN, hydrostatic pressure P on the free surface 静下=0MN.

[0080] For the calculation of uplift pressure of each discrete block, the curtain range is established in 3DE according to the curtain grouting design scheme, the curtain reduction effect is considered, and the curtain reduction coefficient α is defined as the input parameter (see Figure 4 The uplift pressure reduction coefficient in the design parameter input interface is used. Extract the intersection points of the curtain and each sliding surface, and edit formulas (4) to (6) to automatically calculate the uplift pressure P at each point. 扬 , draw vectors along the uplift pressure direction at each point (the length of the vector represents the uplift pressure value), and connect them in sequence to form a three-dimensional uplift pressure graph, such as Figure 5 As shown, the volume is measured to obtain the uplift pressure F on the side sliding surface and bottom sliding surface. 扬 ; When the curtain position changes, the intersection between the curtain and each sliding surface is automatically updated, thereby achieving automatic update of the uplift pressure.

[0081] Formulas (4) to (6) are as follows:

[0082] Upstream side lifting pressure: P 扬 =ρ 水 g(H 上 -H i ) (4)

[0083] Downstream side lifting pressure: P 扬 =ρ 水 g(H 下 -H i ) (5)

[0084] Curtain point pressure: P 扬 =αρ 水 g(H 下 -H i ) (6)

[0085] Where:

[0086] P 扬 Indicates the pressure at each point.

[0087] ρ 水 represents the density of water,

[0088] g represents the acceleration due to gravity, which is 10N / kg.

[0089] H 上 Indicates the upstream water level,

[0090] H 下 Indicates the downstream water level,

[0091] H i Indicates the elevation of each point, which is the Z coordinate of each point.

[0092] α is the curtain reduction coefficient,

[0093] i is the number of each point, which can be named in 3DE according to actual conditions.

[0094] In this embodiment, the curtain reduction coefficient α is 0.35, and the uplift pressure P on the side sliding surface is calculated. 扬侧 =1.12×10 3 MN, uplift pressure P on the bottom sliding surface 扬底 =3.51×10 3 MN.

[0095] For the calculation of seismic inertial force of each discrete block, seismic acceleration a and encounter coefficient ζ are defined as input parameters (see Figure 4 The acceleration and encounter coefficient in the design parameter input interface are combined with the discrete block mass m, and formulas (7) to (9) are edited to automatically calculate the seismic inertia force E in the X, Y, and Z directions. For base earthquake, design earthquake, verification earthquake and other working conditions, the calculation results under different working conditions can be obtained by adjusting the input parameters.

[0096] Formulas (7) to (9) are as follows:

[0097] E X =ma=ρ 岩 Va (7)

[0098] E Y =ξ Y ma=ξ Y ρ 岩 Va (8)

[0099] E Z =ξ Z ma=ξ Z ρ 岩 Va (9)

[0100] Where,

[0101] E x represents the earthquake inertia force in the X direction,

[0102] E Y represents the seismic inertia force in the Y direction,

[0103] E Z represents the seismic inertia force in the Z direction,

[0104] m represents the mass of the discrete block,

[0105] a represents the earthquake acceleration,

[0106] ζ Y represents the coincidence coefficient in the Y direction,

[0107] ζ Zrepresents the encounter coefficient in the Z direction,

[0108] ρ 岩 represents the density of each discrete block,

[0109] V represents the volume of each discrete block.

[0110] In this embodiment, under the design earthquake condition, the earthquake acceleration a=0.1g, the Y-direction encounter coefficient ζ Y =0.85,ζ Z =0.65, calculate the earthquake inertia force E in the X direction x =3.71×10 3 MN, earthquake inertia force E in the Y direction Y =3.15×10 3 MN, seismic inertia force E in the Z direction Z =2.41×10 3 MN.

[0111] For each discrete block, the arch end force F 拱 Calculate and define the arch end force F in the X, Y, and Z directions 拱X 、F 拱Y 、F 拱Z The specific values can be obtained by the arch-beam load sharing method or the finite element method. The arch-beam load sharing method can be calculated using ADAO software, and the results can directly give the cross-river arch thrust, the downstream arch thrust and the vertical arch end thrust.

[0112] In this embodiment, starting from the centroid of the discrete block, vectors are drawn along the direction of each load (the length of the vector represents the load value), and the magnitude and direction of the deadweight, hydrostatic pressure, uplift pressure, seismic force, and arch end force are intuitively displayed. Figure 6 As shown, it is a schematic diagram of the spatial decomposition of the load on one of the discrete blocks in the embodiment of the present invention. The yellow line represents the deadweight, the blue line represents the hydrostatic pressure and uplift pressure, and the black line represents the arch end thrust.

[0113] S5) Superimpose and calculate the load vectors of each discrete block to obtain the resultant force F of the corresponding discrete block in the absolute coordinate system. 合 vector.

[0114] Specifically, the step of superimposing and calculating each type of load vector borne by each discrete block includes projecting each type of load vector in the X, Y, and Z directions of the corresponding absolute coordinate system, and superimposing and calculating the components of all types of load vectors to obtain a resultant force vector representing the corresponding discrete block in the absolute coordinate system.

[0115] In this embodiment, Figure 6 As shown, the red line represents the resultant force, F 合=3.38×10 4 MN.

[0116] S6) Establish a local coordinate system at each particle point, and the Z' direction in the local coordinate system is consistent with the possible sliding direction defined in step S3). Decompose the resultant force vector of each discrete block in step S5) and project it into the Z' direction and the X'Y' plane. Then, perform a secondary decomposition on the resultant force components in the X'Y' plane and project them into the normal directions of the side sliding surface and the bottom sliding surface, respectively. The resultant force component in the Z' direction is the possible sliding force S (action effect) on the three-dimensional block of the dam abutment, and the resultant force components in the normal directions of the side sliding surface and the bottom sliding surface are the normal forces T on each sliding surface on the three-dimensional block of the dam abutment.

[0117] In this embodiment, Figure 6 As shown, the green line represents the component forces of the resultant force vector acting on the discrete block, which is decomposed and projected into three directions (Z' direction, sideslip surface, and normal direction of bottom slip surface). The calculated S=1.10×10 4 MN, T 侧 =4.98×10 2 MN, T 底 =3.17×10 4 MN.

[0118] S7) The cohesive force c and internal friction angle φ of the side and bottom sliding surfaces are used as input parameters in the 3DE. According to the formula anti-slip force = normal force of each sliding surface * friction coefficient + area of each sliding surface * cohesive force, the possible anti-slip force on the three-dimensional block of the dam abutment is calculated.

[0119] Preferably, the anti-sliding stability safety factor K is obtained according to the edited formula (10). According to the provisions of the single safety factor method in the "Code for Design of Concrete Arch Dams" (NB / T 10870-2021), the anti-sliding stability safety factor is the ratio of the side and bottom sliding surface anti-sliding force to the sliding force.

[0120] Formula (10) is as follows:

[0121]

[0122] Where,

[0123] K represents the anti-slip stability safety factor,

[0124] T 侧 represents the normal force on the sideslip surface,

[0125] T 底 represents the normal force on the bottom sliding surface,

[0126] φ 侧 represents the internal friction angle of the sideslip surface,

[0127] φ底 represents the internal friction angle of the bottom sliding surface,

[0128] c 侧 Indicates the adhesion of the sliding surface,

[0129] c 底 Indicates the adhesion of the bottom slip surface,

[0130] A 侧 Indicates the area of the sideslip surface, which can be automatically obtained based on the measurement function of 3DE.

[0131] A 底 Indicates the area of the bottom sliding surface, which can be automatically obtained based on the measurement function of 3DE.

[0132] S represents the sliding force.

[0133] The anti-sliding stability safety factor of the three-dimensional blocks of the dam abutment is obtained, and the stability of the three-dimensional blocks of the dam abutment is determined by comparing the anti-sliding stability safety factor with the minimum safety factor.

[0134] In this embodiment, c 侧 =0.84, c 底 =0.84,φ 侧 =30.4,φ 底 =30.4, and the calculated anti-sliding stability safety factor K=3.13.

[0135] According to the requirements of the Code for Seismic Design of Hydraulic Structures in Hydropower Engineering (NB 35047-2015), when the anti-sliding stability limit state design formula is used to check the stability of the abutment rock mass, the partial coefficient of the rock mass material performance is taken as 1.0, while the corresponding structural coefficient γ is taken as 1.0 when the pseudo-static method is used to calculate the seismic load. d It should be 2.7, which is equivalent to the minimum safety factor K min Should be:

[0136] K min =γ0γ d ψ

[0137] Where,

[0138] γ0 is the structural importance coefficient, which is 1.0 for this project with structural safety level I.

[0139] ψ is the design condition coefficient, which is 0.85 for earthquake conditions.

[0140] Therefore, this project K min =2.3, while in this project, K=3.13>K under normal water level + design earthquake conditions min , indicating that the anti-sliding stability and safety of the dam abutment blocks under this working condition meet the requirements of the specifications.

[0141] The 3DE-based three-dimensional block stability analysis method for dam abutments of the present invention can, on the one hand, intuitively display the block morphology and load distribution in three-dimensional form according to changes in water level and anti-seepage curtain design scheme, and support dynamic adjustment of viewing angle and scaling ratio; on the other hand, it can automatically determine the possible sliding direction of the three-dimensional blocks of the dam abutment, and automatically perform load space decomposition on the platform to determine the possible sliding force and possible anti-sliding force of the three-dimensional blocks of the dam abutment; the present invention overcomes the limitations of traditional methods through an efficient, accurate and visual analysis method, improves calculation efficiency, ensures the accuracy of calculation results, and promotes technological progress in related fields.

[0142] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A 3DE-based three-dimensional block stability analysis method for dam abutments, characterized by: The steps include: S1) constructing a three-dimensional geological model of the dam abutment area in 3DE, wherein the three-dimensional geological model includes lithology distribution and structural surface characteristics; S2) Based on the 3D geological model, the 3D block of the dam abutment is divided into discrete blocks through the spatial cutting relationship of the structural surface; S3) Extract each structural surface of each discrete block in 3DE, and define the side slip surface, bottom slip surface, upstream tensile fracture surface and free surface in each structural surface, and define the intersection direction between the side slip surface and the bottom slip surface as the possible sliding direction of the 3D block of the dam abutment; S4) obtaining the centroid of each discrete block and establishing an absolute coordinate system at each centroid; inputting parameters into the 3DE and automatically calculating various types of loads on each discrete block by editing formulas; Starting from the centroid of each discrete block, vectors are drawn along the direction of each type of load, and the length of the vector represents the load value, thereby achieving an intuitive display of the magnitude and direction of each type of load; S5) superimposing and calculating the load vectors of each type acting on each discrete block to obtain the resultant force vector acting on the corresponding discrete block in the absolute coordinate system; S6) establishing a local coordinate system at each mass point, with the Z' direction in the local coordinate system being consistent with the possible sliding direction defined in step S3), decomposing the resultant force vector acting on each discrete block in step S5) and projecting it into the Z' direction and the X'Y' plane, then performing a secondary decomposition on the resultant force components in the X'Y' plane and projecting them onto the normals of the sideslip surface and the bottom slip surface, respectively, where the resultant force component in the Z' direction is the possible sliding force acting on the three-dimensional block of the dam abutment, and the resultant force components in the normal directions of the sideslip surface and the bottom slip surface are the normal forces acting on each sliding surface on the three-dimensional block of the dam abutment; S7) The cohesive force and internal friction angle of the side and bottom sliding surfaces are used as input parameters in the 3DE. According to the formula of anti-slip force = normal force of each sliding surface * friction coefficient + area of each sliding surface * cohesive force, the possible anti-slip force on the three-dimensional block of the dam abutment is calculated.

2. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 1 is characterized by: In S1), constructing a 3D geological model includes the following steps: importing the original landform in the dam abutment area into 3DE, and establishing a 3D terrain model after the project implementation in combination with the dam abutment excavation plan; based on the 3D terrain model, importing the spatial distribution information of lithologic interfaces, faults, and joints, thereby realizing the construction of a 3D geological model.

3. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 2 is characterized by: In S2), the step of dividing the three-dimensional block of the dam abutment into discrete blocks includes automatically identifying potential unstable blocks through the block theory algorithm in 3DE, and dividing the potential unstable blocks into discrete blocks based on the spatial cutting relationship of the structural surface.

4. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 3 is characterized by: In S3), before extracting each structural surface of each discrete block, it is necessary to visually display the spatial position of each discrete block through 3DE and determine the properties of each structural surface of each discrete block.

5. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 1 is characterized by: In S4), the centroid of each discrete block is obtained based on the measurement function of 3DE, and the X, Y, and Z directions in the absolute coordinate system are determined to correspond to the downstream, cross-river, and vertical directions in the project, respectively.

6. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 5 is characterized by: In S4), the various types of loads on each discrete block include gravity, hydrostatic pressure, uplift pressure, seismic inertia force, and arch end force.

7. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 6 is characterized by: In S4), for the gravity calculation of each discrete block, it is necessary to automatically obtain the volume of each discrete block based on the measurement function of 3DE, define the density of each discrete block as an input parameter, and edit the formula to automatically obtain the block gravity.

8. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 1 is characterized by: In S5), the step of superimposing and calculating each type of load vector borne by each discrete block includes projecting each type of load vector in the X, Y, and Z directions of the corresponding absolute coordinate system, and superimposing and calculating the components of all types of load vectors to obtain a resultant force vector representing the corresponding discrete block in the absolute coordinate system.

9. The 3DE-based three-dimensional block stability analysis method for dam abutments according to claim 1 is characterized by: In S7), the anti-sliding stability safety factor of the three-dimensional blocks of the dam abutment is calculated according to the formula: anti-sliding stability safety factor = anti-sliding force / sliding force. The stability of the three-dimensional blocks of the dam abutment is determined by comparing the anti-sliding stability safety factor with the minimum safety factor.

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