CN117669081A - A design method for arch dam foundation excavation - Google Patents

Abstract

The invention discloses an arch dam foundation excavation design method, belongs to the technical field of water conservancy and hydropower engineering, and can solve the problems that the existing arch dam excavation design is long in time and difficult to control in excavation slope ratio. The method comprises the following steps: s1, creating an excavation surface at the upper part of a dam top on a terrain geological model of an arch dam site area according to a three-dimensional model of an arch dam body; s2, constructing a layered excavation datum line from the elevation of the bottom surface of the dam body to the elevation of the top surface of the dam body on the terrain geological model, and creating a dam body excavation surface according to the layered excavation datum line; s3, creating a dam foundation excavation model according to the upper excavation surface of the dam top and the dam body excavation surface. The method is used for designing the arch dam foundation excavation model.

Description

A design method for arch dam foundation excavation

Technical field

The invention relates to an arch dam foundation excavation design method and belongs to the technical field of water conservancy and hydropower engineering.

Background technique

As a commonly used dam type in hydropower projects, arch dams are widely used in various water conservancy and hydropower projects and play a huge role in the development of the national economy. Arch dams are generally built in mountain canyons with steep river bank slopes, complex topographic and geological conditions, and complex body shapes of the arch dams. Foundation excavation has always been the focus and difficulty of arch dam design.

The existing technology usually uses three-dimensional software modeling or CAD software for excavation design, which has the following shortcomings: 1. The arch dam foundation is excavated using the radial section method. The excavation section needs to determine the geological conditions according to the arch dam shape and draw it. Excavation design can only be carried out after the geological profile is obtained. When the shape of the arch dam changes, the geological profile needs to be redrawn and then the excavation design is carried out. This requires multiple coordination between the designer and geological experts, and the design work time will be significantly increased. 2. The radial cross-section excavation method is inconvenient to control the excavation slope ratio. The slope in the cross-section excavation diagram is inconsistent with the designed slope and is not the excavation direction designed for slope excavation. 3. Traditional excavation methods cannot coordinate the excavation slope as a whole, and the coordination and control of the excavation slope are not intuitive.

Contents of the invention

The invention provides an arch dam foundation excavation design method, which can solve the problems that the existing arch dam excavation design requires a long time and the excavation slope ratio is difficult to control.

The invention provides an arch dam foundation excavation design method, which method includes:

S1. Based on the three-dimensional model of the arch dam body, create an excavation surface for the upper part of the dam crest on the topographic and geological model of the arch dam site area;

S2. Construct a layered excavation baseline from the bottom elevation of the dam to the top elevation of the dam on the topographic geological model, and create a dam excavation surface based on the layered excavation baseline;

S3. Create a dam foundation excavation model based on the upper excavation surface of the dam crest and the dam body excavation surface.

Optionally, after S3, the method further includes:

The excavation slope ratio in the dam foundation excavation model is adjusted according to the topographic geological model to obtain an updated dam foundation excavation model.

Optionally, before S1, the method further includes:

Draw a three-dimensional model of the dam body based on the design parameters of the arch dam, and draw a topographic and geological model of the arch dam site area based on the geological data of the dam site area.

Optional, the S1 is specifically:

Based on the three-dimensional model of the dam body and the geological data of the dam site area, the cross-section method was used to create the upper excavation surface of the dam crest on the topographic geological model of the arch dam site area.

Optionally, in S2, a layered excavation baseline from the bottom elevation of the dam to the top elevation of the dam is constructed on the topographic geological model, specifically:

Determine the excavation profile of the dam body on the elevation of the dam bottom surface, as well as the excavation layer height and excavation slope ratio of layered excavation;

According to the excavation contour of the dam body and the excavation layer height and excavation slope ratio of the layered excavation, the layered excavation baseline of each layer of excavation surface is determined.

Optionally, according to the excavation contour of the dam body and the excavation layer height and excavation slope ratio of the layered excavation, determine the layered excavation baseline of each layer of excavation surface, specifically as follows:

The excavation contour of the dam body is used as the base line of the bottom excavation, and the excavation level of the upper layer of excavation surface is determined based on the base line of the bottom layer of excavation and the excavation layer height and excavation slope ratio of the upper layer of excavation surface. dig edge;

According to the excavation edge line and the reserved horse road width, a layered excavation datum line for the upper layer of excavation surface is formed, and the layered excavation datum line is used as the bottom layer excavation datum line, and each layer is determined layer by layer in turn. The layered excavation datum line for the excavation face.

Optionally, in S2, creating a dam excavation surface based on the hierarchical excavation baseline includes:

Correspondingly connect the turning points on the excavation edge line of each layer of excavation surface with the turning points on the corresponding bottom excavation baseline to form the guide line of each layer of excavation surface;

Create a dam excavation surface based on the layered excavation baseline and the guide line.

Optionally, create a dam excavation surface based on the layered excavation baseline and the guide line, specifically including:

Form an excavation slope surface according to the layered excavation baseline and the guide line;

The horse track surface is formed by filling, and the horse track surface is joined with the excavation side slope surface to form the dam body excavation surface.

Optionally, adjust the excavation slope ratio in the dam foundation excavation model according to the topographic geological model to obtain an updated dam foundation excavation model, specifically:

The layered excavation baseline in the dam foundation excavation model is adjusted according to the excavation surface cut by the topographic geological model to obtain an updated dam foundation excavation model.

Optionally, the rock layer weathering types of the topographic geological model are divided into strongly weathered layer, weak weathered layer and lightly weathered layer from top to bottom.

The beneficial effects produced by this invention include:

(1) The arch dam foundation excavation design method provided by the present invention constructs a layered excavation datum line from the bottom surface of the dam body to the top surface through plane layering to create the dam body excavation surface. The present invention changes the traditional method of using radial sections to design arch dam foundation excavation, and can design the excavation surface by combining the geological two-dimensional plan view of the arch dam site area and the three-dimensional geological weathering model. In addition, for arch dams, both the longitudinal and horizontal excavation slopes will change and are related to each other. Therefore, the present invention facilitates the overall adjustment of the excavation surface through parametric design of the hierarchical excavation baseline, and can quickly form an excavation surface. Dig in and see the overall effect after adjustment, which greatly improves design quality and efficiency.

(2) The arch dam foundation excavation design method provided by the present invention establishes a horizontal layered excavation reference line to facilitate construction setting out and control the excavation slope ratio, and better integrates design drawings and construction, thereby accelerating the construction progress. At the same time, the present invention uses three-dimensional entity classification for excavation to directly check the rationality of the slope design from the color of the excavation surface, thereby facilitating the adjustment of the slope design.

Description of drawings

Figure 1 is a flow chart of the arch dam foundation excavation design method based on the CATIA platform provided by the embodiment of the present invention;

Figure 2 is a schematic diagram of a three-dimensional terrain geological model provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of a three-dimensional model of a dam provided by an embodiment of the present invention;

Figure 4 is a schematic diagram of the excavation surface creation of the dam crest and abutment slope provided by the embodiment of the present invention;

Figure 5 is a schematic diagram of the layered excavation baseline and guide lines provided by the embodiment of the present invention;

Figure 6 is a schematic diagram of the excavation surface of the upper part of the dam crest and the excavation surface of the dam body provided by the embodiment of the present invention;

Figure 7 is a schematic diagram of excavation adjustment provided by the embodiment of the present invention;

Figure 8 is a schematic diagram of the overall effect after excavation is completed according to the embodiment of the present invention.

Parts and reference number list:

1. Geological drilling points; 2. Topographic surface; 3. Strong weathering lower limit surface; 4. Weak weathering lower limit surface; 5. Strong weathering layer; 6. Weak weathering layer; 7. Slightly weathered layer; 8. Three-dimensional model of dam body ; 9. Top of arch dam; 10. Bottom of arch dam; 11. Top of right dam abutment; 12. Top of left dam abutment; 13. Baseline of slope excavation; 14. Normal profile of excavation section; 15. Upper part of dam crest Excavation surface; 16. Baseline of the bottom of the arch dam model; 17. Dam base elevation datum; 18. Dam excavation outline; 19. First layer of horse track elevation datum; 20. First layer excavation edge line; 21. Guide line; 22. First layer excavation datum line; 23. Excavation surface at the top of the left abutment; 24. Excavation surface at the top of the right abutment; 25. Dam body excavation surface; 26. Layered excavation datum line; 27. Adjust the projection distance of the front and rear baselines; 28. Dam foundation excavation result surface; 29. Left dam abutment excavation result surface; 30. Right dam abutment excavation result surface; 31. Horse road excavation result surface; 32. Breeze excavation Excavation slope; 33. Excavation slope with weak weathering; 34. Excavation slope with strong weathering.

Detailed ways

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

An embodiment of the present invention provides an arch dam foundation excavation design method, as shown in Figures 1 to 8. The method includes:

S1. Based on the three-dimensional model 8 of the arch dam body, create an excavation surface 15 for the upper part of the dam crest on the topographic and geological model of the arch dam site area.

Before S1, the method further includes:

Draw a three-dimensional model of the dam body based on the design parameters of the arch dam8, and create a topographic and geological model of the arch dam site area based on the geological data of the dam site area. Among them, the terrain geological model is created based on the rock layer weathering type, which is divided into strongly weathered layer 5, weak weathered layer 6 and lightly weathered layer 7 from top to bottom.

The topographic and geological model of the dam site area is jointly created through the terrain surface and the three-dimensional geological weathering surface of the dam foundation established based on the previous geological survey results. CATIA spline curves are used to form the arch dam baseline in layers and form a three-dimensional model of the dam body8.

Figure 2 is a schematic diagram of a three-dimensional terrain geological model provided by an embodiment of the present invention. As shown in Figure 2, the geological drilling point 1 is the data provided by geological exploration; the terrain surface 2 is a curved surface generated using point clouds on the CATIA platform; strong weathering The lower limit surface 3 and the weakly weathered lower limit surface 4 are surfaces generated by using the GOCAD software to fit the point cloud results based on the measured data of the geological survey holes, and then using the CATIA platform; the strongly weathered layer 5 is the middle surface between the terrain surface 2 and the strong weathering lower limit surface 3 The weakly weathered layer 6 is the rock mass between the strong weathering lower limit curved surface 3 and the weakly weathered lower limit curved surface 4; the slightly weathered layer 7 is the part of the rock mass below the weakly weathered lower limit curved surface 4.

Figure 3 is a schematic diagram of the three-dimensional model 8 of the dam body provided by the embodiment of the present invention. As shown in Figure 3, the top 9 of the arch dam is the plane where the highest point of the three-dimensional model 8 of the dam body is; the bottom surface 10 of the arch dam is the plane where the lowest point of the three-dimensional model 8 of the dam body is; the top 11 of the right abutment is the plane where the top 9 of the arch dam is. The right end position of the water flow direction; the left dam abutment 12 is the left end position of the arch dam crest 9 along the flow direction.

S1 is specifically:

According to the three-dimensional model of the dam body8 and the current geological conditions of the dam site area, the cross-section method was used to create the excavation surface of the upper part of the dam crest15 on the topographic geological model of the arch dam site area.

Obtain the topographic and geological model of the arch dam site area and the three-dimensional model of the arch dam body8. The excavation design above the dam crest should be combined with the road layout, and the slope excavation design parameters should be determined according to the geological conditions and relevant design specifications. The section method is used to create the excavation surface 15 on the upper part of the dam crest.

Figure 4 is a schematic diagram of the excavation surface creation of the dam crest and abutment slope provided by the embodiment of the present invention. As shown in Figure 4, the slope excavation baseline 13 is the slope excavation baseline designed based on the actual layout of the project, and is used as a guide line to form the excavation surface; the excavation section normal profile 14 is the design of the excavation site Section, including slope excavation slope height, slope, horse path and other related design parameters; the excavation surface 15 on the upper part of the dam top is made by using the sweep command in CATIA, using the excavation section normal profile 14 as the section sketch and the side slope excavation Digging baseline 13 is the surface generated by the guide line.

S2. Construct a layered excavation baseline 26 from the bottom elevation of the dam to the top elevation of the dam on the topographic geological model, and create the dam excavation surface 25 based on the layered excavation baseline 26.

According to the excavation plan, starting from the elevation of the dam bottom surface, the arch dam excavation baseline (i.e., the layered excavation baseline 26) is established according to the plane layering method. Based on the layered excavation baseline 26, the dam body excavation is created with a multi-section command. Side 25.

Specifically include:

(1) Determine the dam excavation profile 18 on the dam bottom elevation, as well as the excavation layer height and excavation slope ratio for layered excavation.

(2) According to the excavation contour 18 of the dam body and the excavation layer height and excavation slope ratio of the layered excavation, determine the layered excavation baseline 26 of each layer of excavation surface. Among them, the dam excavation profile 18 and the excavation layer height and excavation slope ratio of layered excavation must meet relevant specifications and construction condition requirements.

Specifically:

The dam body excavation contour 18 is used as the bottom excavation datum line, and the excavation edge line of the upper layer excavation surface is determined based on the bottom excavation datum line and the excavation layer height and excavation slope ratio of the upper layer excavation surface.

According to the excavation edge line and the width of the reserved horse road, a layered excavation datum line 26 of the upper layer of excavation surface is formed, and the layered excavation datum line 26 is used as the bottom layer excavation datum line, and each layer of excavation is determined layer by layer. The layered excavation datum line 26 on the surface.

In practical applications, the excavation outline of the lowest layer of the dam is first determined18, and then the excavation layer height and slope ratio are initially determined based on the topography of the dam abutment and geological weathering conditions, and the excavation edge line of the upper layer is formed in a broken line. On this basis, a horse track is left to form the base excavation baseline of the next layer, and so on to complete the layered excavation baseline 26 of the arch dam foundation.

(3) Correspondingly connect the turning points on the excavation edge line of each layer of excavation surface with the turning points on the corresponding bottom layer excavation baseline to form the guide line 21 of each layer of excavation surface.

First determine the base line of the excavation boundary from the bottom surface 10 of the arch dam (using a polyline), and then establish the base line of the excavation boundary at that elevation at the first layer of horse road elevation datum 19 based on the height of the excavation platform, that is, the first layer of excavation. Side line 20, the distance of this excavation side line is determined according to the geological weathering type and converted into a horizontal distance according to the excavation slope ratio to determine the position of the excavation boundary baseline of this layer. After the excavation datum line is completed, use this as a basis to complete the excavation boundary datum line of the bridleway according to the designed bridleway width, which will be used as the bottom excavation datum line for the next layer of excavation, and so on to complete the layered excavation datum below the dam top. To determine the line 26, finally based on the design of the excavation boundary baseline, the upper and lower points of the turning point of the polyline are connected correspondingly as the guide line 21 for the excavation to form the excavation surface. According to the direction of each guide line, the effective slope ratio of the excavation is further controlled. , and facilitate later excavation optimization design.

(4) Create the dam excavation surface 25 based on the layered excavation reference line 26 and the guide line 21.

Specifically, it includes: first forming the excavation slope surface according to the layered excavation reference line 26 and the guide line 21; then forming the horse track surface by filling, and joining the horse track surface and the excavation side slope surface to form the dam body excavation surface 25.

Figure 5 is a schematic diagram of the layered excavation reference line 26 and the guide line 21 provided by the embodiment of the present invention. Referring to Figure 5, the base line 16 at the bottom of the arch dam model is the outline of the arch dam bottom surface 10; the elevation datum plane 17 of the dam bottom surface is the elevation surface where the arch dam bottom surface 10 is located, which is used to locate the excavation sketch; The excavation outline 18 is the excavation boundary line designed based on the bottom baseline 16 of the arch dam model. Generally, the range of the arch dam model bottom baseline 16 is smaller than the range included in the dam excavation outline 18. The dam excavation outline 18 and the above-mentioned baseline are both It is in the shape of a broken line to adapt to different spatial relationships; the elevation datum 19 of the first-level horse track is the elevation plane where the first-level horse track is located starting from the elevation datum 17 of the bottom of the dam determined according to the geological conditions and design layout; The excavation edge line 20 is an excavation datum line designed based on the projection relationship between the dam body excavation contours 18. The first layer excavation edge line 20 and the dam body excavation contour 18 form the first layer of excavation through the guide line 21 of the excavation boundary. layer excavation curved surface; the guide line 21 of the excavation boundary is the connection line between the corresponding points of the excavation contour 18 of the dam body and the polyline of the first layer excavation edge line 20, which is used to control the excavation slope ratio;

The first layer of excavation datum line 22 is a boundary datum line designed based on a certain distance offset from the first layer of excavation edge line 20 (the design width of the horse track), and forms a horse path platform with the first layer of excavation edge line 20, and so on. The one-layer excavation baseline 22 serves as the baseline for the next excavation surface, and the creation and surface generation of the excavation baseline below the dam top are completed in sequence; based on the layered excavation baseline 26, layers are created according to CATIA's multi-section command For the excavation surface, use the guide line 21 to control the direction of the excavation, and form the excavation slope in sequence. Then use the curved surface filling command to form the road surface, and finally use the joint command to bond it into a curved surface to form the excavation surface 25 of the dam body below the dam top. .

Figure 6 is a schematic diagram of the upper excavation surface 15 of the dam crest and the excavation surface 25 of the dam body provided by the embodiment of the present invention. As shown in Figure 6, the excavation surface 23 at the top of the left dam abutment is the excavation curved surface above the elevation of the left dam abutment 12, and is used to cut the rock mass on the left side of the arch dam crest 9; the excavation surface at the top of the right dam abutment 24 is the excavation curved surface of the part above the elevation of the right dam abutment 11, which is used to cut the rock mass on the right side of the arch dam crest 9; the dam body excavation surface 25 is the middle part of the arch dam crest 9 and the arch dam bottom surface 10 The excavation curved surface is used to cut the rock mass in the middle part of the arch dam crest 9 and the arch dam bottom 10, and finally complete the foundation excavation of the arch dam.

S3. Create a dam foundation excavation model based on the upper excavation surface 15 of the dam crest and the dam body excavation surface 25.

Further, after S3, the method also includes:

The excavation slope ratio in the dam foundation excavation model was further adjusted and optimized based on the terrain geological model to obtain an updated dam foundation excavation model.

Specifically, according to the excavation image of the preliminary cut terrain geological model, combined with the weathering conditions of the rock mass, the directions of the layered excavation baseline 26 and the guide line 21 in the dam foundation excavation model are further adjusted to obtain the updated dam foundation excavation. Dig the model.

The excavation surface is adjusted according to the geological conditions and the excavation is carried out according to the weathering category. Figure 7 is a schematic diagram of excavation adjustment provided by the embodiment of the present invention. Referring to Figure 7, the layered excavation datum line 26 is the design datum line of each layer including the dam excavation outline 18, the first layer excavation edge line 20, and the first layer excavation datum line 22; before and after adjustment The baseline projection distance 27 is the distance between the baseline projections of the excavation surfaces at each layer, and controls the excavation slope ratio together with the guide line 21 of the excavation boundary. Figure 7 shows that before adjustment, the baseline projection distance of the excavation surface of this layer was 10. After adjusting the excavation baseline, the baseline projection distance of the excavation surface of this layer became 12.5.

According to the dam foundation excavation model formed in step S3 and the weathering categories revealed on the excavation surface, the position of the horizontal excavation baseline (i.e., the layered excavation baseline 26) is continuously adjusted from bottom to top, from the dam abutment to the middle of the river channel as needed. and the direction of the guide line 21 until the excavation slope of each layer is consistent with the geological conditions. The standards that are consistent and reasonable are: the slope connection is smooth, the slope ratio of the segmented excavation is compatible with the weathered geological conditions, and the terrain conditions are suitable.

After the final excavation surface is determined, the excavation update of the arch dam foundation is completed through refreshing, which can effectively save design modification time, improve design work efficiency and product quality, and then count the excavation volume according to actual needs.

Figure 8 is a schematic diagram of the overall effect after excavation is completed according to the embodiment of the present invention. Figure 8 shows the dam foundation excavation result surface 28, the left dam abutment excavation result surface 29, the right dam abutment excavation result surface 30, the horse road excavation result surface 31, the lightly weathered excavation slope surface 32, and the weakly weathered excavation slope surface. Surface 33 and strongly weathered excavation slope 34, the excavation results can be used to draw drawings and calculate engineering quantities. Among them, the slope of the excavation slope from steep to gentle should be the slope of the lightly weathered excavation slope 32 < the slope of the weakly weathered excavation slope 33 < the slope of the strongly weathered excavation slope 34.

First, use the excavation surface 15 on the upper part of the dam crest to complete the excavation above the dam crest according to the weathering category, and then use the CATIA cutting command to complete the excavation entities of different weathering categories according to the excavation surface 25 of the dam body. Based on the completion of the excavation, review the overall excavation to see if it meets the overall design requirements. If adjustments are needed, you can adjust the excavation surface from bottom to top by adjusting the position of the layered excavation guide line, and complete the excavation through the refresh command of CATIA Make adjustments until the design requirements are met. Finally, the measurement commands of CATIA are used to complete the classification engineering quantity statistics.

The present invention constructs the layered excavation reference line 26 from the bottom surface to the top surface of the dam body in a plane layering manner to create the dam body excavation surface 25. The present invention changes the traditional method of using radial sections to design arch dam foundation excavation, and can design the excavation surface by combining the geological two-dimensional plan view of the arch dam site area and the three-dimensional geological weathering model. In addition, for arch dams, both the longitudinal and horizontal directions of the excavation slope will change and are related to each other. Therefore, the present invention facilitates the overall adjustment of the excavation surface through parametric design of the hierarchical excavation baseline 26, and can quickly form Excavate the surface and check the overall effect after adjustment, which greatly improves the design quality and efficiency.

By establishing a horizontal layered excavation reference line 26, the present invention facilitates construction setting out and control of excavation slope ratio, and better integrates design drawings and construction, thereby accelerating construction progress. At the same time, the present invention uses three-dimensional entity classification for excavation to directly check the rationality of the slope design from the color of the excavation surface, thereby facilitating the adjustment of the slope design.

The above are only a few embodiments of the present application, and are not intended to limit the present application in any way. Although the present application is disclosed as above with preferred embodiments, they are not intended to limit the present application. Any skilled person familiar with this field, Without departing from the scope of the technical solution of this application, slight changes or modifications made using the technical content disclosed above are equivalent to equivalent implementation examples and fall within the scope of the technical solution.

Claims (10)

1. An arch dam foundation excavation design method, characterized in that the method includes: S1. Based on the three-dimensional model of the arch dam body, create an excavation surface for the upper part of the dam crest on the topographic and geological model of the arch dam site area; S2. Construct a layered excavation baseline from the dam bottom elevation to the dam top elevation on the topographic geological model, and create a dam excavation surface based on the layered excavation baseline; S3. Create a dam foundation excavation model based on the upper excavation surface of the dam crest and the dam body excavation surface. 2. The method according to claim 1, characterized in that, after the S3, the method further includes: The excavation slope ratio in the dam foundation excavation model is adjusted according to the topographic geological model to obtain an updated dam foundation excavation model. 3. The method according to claim 1, characterized in that, before the S1, the method further includes: Draw a three-dimensional model of the dam body based on the design parameters of the arch dam, and draw a topographic and geological model of the arch dam site area based on the geological data of the dam site area. 4. The method according to claim 1, characterized in that, the S1 is specifically: Based on the three-dimensional model of the dam body and the geological data of the dam site area, the cross-section method was used to create the upper excavation surface of the dam crest on the topographic geological model of the arch dam site area. 5. The method according to claim 1, characterized in that in S2, a layered excavation baseline from the bottom elevation of the dam body to the elevation of the dam top surface is constructed on the topographic geological model, specifically: Determine the excavation profile of the dam body on the elevation of the dam bottom surface, as well as the excavation layer height and excavation slope ratio of layered excavation; According to the excavation contour of the dam body and the excavation layer height and excavation slope ratio of the layered excavation, the layered excavation baseline of each layer of excavation surface is determined. 6. The method according to claim 5, characterized in that the layered excavation of each layer of excavation surface is determined according to the excavation profile of the dam body and the excavation layer height and excavation slope ratio of the layered excavation. Baseline, specifically: The excavation contour of the dam body is used as the base line of the bottom excavation, and the excavation level of the upper layer of excavation surface is determined based on the base line of the bottom layer of excavation and the excavation layer height and excavation slope ratio of the upper layer of excavation surface. dig edge; According to the excavation edge line and the reserved horse road width, a layered excavation datum line for the upper layer of excavation surface is formed, and the layered excavation datum line is used as the bottom layer excavation datum line, and each layer is determined layer by layer in turn. The layered excavation datum line for the excavation face. 7. The method according to claim 6, characterized in that, in S2, creating a dam excavation surface based on the hierarchical excavation baseline specifically includes: Correspondingly connect the turning points on the excavation edge line of each layer of excavation surface with the turning points on the corresponding bottom excavation baseline to form the guide line of each layer of excavation surface; Create a dam excavation surface based on the layered excavation baseline and the guide line. 8. The method according to claim 7, characterized in that creating a dam excavation surface based on the layered excavation baseline and the guide line specifically includes: Form an excavation slope surface according to the layered excavation baseline and the guide line; The horse track surface is formed by filling, and the horse track surface is joined with the excavation side slope surface to form the dam body excavation surface. 9. The method according to claim 2, characterized in that the excavation slope ratio in the dam foundation excavation model is adjusted according to the topographic geological model to obtain an updated dam foundation excavation model, specifically: The layered excavation baseline in the dam foundation excavation model is adjusted according to the excavation surface cut by the topographic geological model to obtain an updated dam foundation excavation model. 10. The method according to claim 1, characterized in that the rock formation weathering types of the topographic geological model are divided into strongly weathered layer, weak weathered layer and lightly weathered layer from top to bottom.