Arrangement method of curtain grouting holes at the axis turning point

Abstract

The present invention discloses a layout method for curtain grouting holes at the axis turning point, including: ① calculating the horizontal projection lengths of two adjacent grouting holes on different axes in the plane according to the design value of the curtain grouting bottom line and the inclination angle of the grouting holes, and marking; ② selecting two points between the two adjacent grouting holes as the starting drilling positions of the grouting strengthening holes, and the connecting lines of the grouting strengthening holes and the adjacent grouting holes in the plane are smooth curves; ③ connecting the horizontal projection ends of the two adjacent grouting holes in step one with an arc, trisecting the arc, and the connecting line between the starting drilling position of the grouting strengthening hole and the corresponding trisection point is the horizontal projection of the drilling surface of the grouting strengthening hole; ④ drilling upstream from the starting drilling position of the grouting strengthening hole in its drilling surface, with the drilling angle being the same as that of the two adjacent grouting holes, and the drilling depth being the average value of the depths of the two adjacent grouting holes. The present invention can avoid the leakage of the grouting curtain at the turning point and reduce the seepage of the dam foundation.

Description

Technical Field

[0001] The present invention relates to the technical field of curtain grouting at the abutment of a dam, and particularly to a layout method of curtain grouting holes at the turning point of the axis. Background Art

[0002] In a concrete dam project, a foundation gallery is usually arranged at the part of the dam body near the upstream surface, and a grouting curtain is arranged in the gallery. The inclination angle of the grouting curtain is determined according to the occurrence of the bedrock structural plane, and the number of rows can be determined according to different dam heights. In general, in order to form a closed curtain, the curtain grouting is arranged on the same axis as much as possible, or a connecting curtain is arranged between the upper and lower layers of grouting holes. However, at the abutment of the dam, when the curtain grouting holes are not on the same axis, there will be a problem of spatial connection at the turning point, resulting in a certain empty area. When the curtain grouting cannot form a closed space, it will increase the uplift pressure and seepage volume of the dam foundation, endangering the safety of the dam. Summary of the Invention

[0003] The purpose of the present invention is to provide a layout method of curtain grouting holes at the turning point of the axis to solve the connection problem of curtain grouting holes not on the same axis at the turning point of the axis and make them form a closed curtain.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] The layout method of curtain grouting holes at the turning point of the axis according to the present invention includes

[0006] The first step is to calculate the horizontal projection lengths of two adjacent grouting holes on different axes in the plane according to the design value of the bottom line of the curtain grouting and the inclination angle of the grouting holes, and mark them at their ends;

[0007] The second step is to select two points between the two adjacent grouting holes in the first step as the starting positions of the grouting reinforcement holes. The connecting lines of the grouting reinforcement holes and the adjacent grouting holes in the plane are smooth curves;

[0008] The third step is to connect the marked ends of the horizontal projections of the two adjacent grouting holes in the first step with an arc, and divide the arc into three equal parts. The connecting line between the starting position of the grouting reinforcement hole and the corresponding trisection point is the horizontal projection of the drilling surface of the grouting reinforcement hole;

[0009] The fourth step is to drill upstream from the starting position of the grouting reinforcement hole in its drilling surface. The drilling angle is the same as that of the two adjacent grouting holes, and the drilling depth is the average value of the depths of the two adjacent grouting holes.

[0010] The grouting holes are arranged to incline 3 - 5° upstream.

[0011] The arrangement method of curtain grouting holes at the axis turning point provided by the present invention is particularly applicable to curtain grouting at the dam shoulder. By means of the fan-shaped arrangement structure of curtain grouting holes at the axis turning point, two rows of curtain grouting on different axes are changed into one row, avoiding the leakage of the grouting curtain at the turning point, and truly forming a closed curtain, reducing the seepage of the dam foundation. The curtain grouting described in the present invention usually acts jointly with drainage holes to achieve the purpose of reducing the uplift pressure of the dam foundation behind the grouting curtain and ensuring the stability of the dam. Brief Description of the Drawings

[0012] Figure 1 It is a schematic structural view of the fan-shaped arrangement of the curtain grouting holes described in the present invention. Detailed Embodiment

[0013] The following describes in detail the embodiments of the present invention with reference to the drawings. The present embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific construction processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0014] As Figure 1 shown, in this embodiment, two rows of grouting holes K are arranged in the grouting gallery M. Among them, the first grouting hole 1 and the second grouting hole 2 are connected, and the first grouting hole 2 is located at the end of the first row, and the second grouting hole 2 is located at the beginning of the second row. Therefore, they are connected but not on the same axis. In order to avoid the leakage of the grouting curtain at the turning point, increase the uplift pressure of the dam foundation, and threaten the safety of the dam, two grouting strengthening holes, namely the first grouting strengthening hole 3 and the second grouting strengthening hole 4, are arranged between the first grouting hole 1 and the second grouting hole 2. By means of the two holes, two rows of curtain grouting on different axes are changed into one row, thereby forming a closed curtain, reducing the seepage of the dam foundation. At the same time, under the combined action of the drainage holes, it can truly achieve the reduction of the uplift pressure of the dam foundation behind the grouting curtain and ensure the stability of the dam. (It should be noted that in this embodiment, there are two grouting strengthening holes, and one or more holes can also be set according to specific construction conditions.) Specifically, the arrangement method of the curtain grouting holes at the axis turning point described in the present invention includes

[0015] The first step is to calculate the horizontal projection lengths of two adjacent grouting holes (the first grouting hole 1 and the second grouting hole 2) on different axes in the plane according to the design value of the bottom line of the curtain grouting and the inclination angle of the grouting hole K, and mark at the end of the horizontal projection;

[0016] The second step is to select two points between the first grouting hole 1 and the second grouting hole 2 as the starting drilling positions of the first grouting strengthening hole 3 and the second grouting strengthening hole 4. The connecting lines of the above-mentioned first grouting hole 1, the first grouting strengthening hole 3, the second grouting strengthening hole 4 and the second grouting hole 2 in the plane are smooth curves;

[0017] Step 3: Connect the end marks of the horizontal projections of the first grouting hole 1 and the second grouting hole 2 with an arc R, and trisect the arc R. The connection line between the trisection points of the arc R and the starting positions of the corresponding grouting reinforcement holes is the horizontal projection of the drilling surface of the grouting reinforcement holes.

[0018] Step 4: Drill upstream from the starting positions of the first grouting reinforcement hole 3 and the second grouting reinforcement hole 4 within their respective drilling surfaces. The drilling angle is the same as that of the first grouting hole 1 and the second grouting hole 2 (i.e., inclined 3-5° upstream), and the drilling depth is the average of the depths of the first grouting hole 1 and the second grouting hole 2.

[0019] In Figure 1 , L1 and L2 are the horizontal projection lengths of the first grouting hole 1 and the second grouting hole 2 at the designed depth, b is the distance between the first grouting hole 1 and the second grouting hole 2; d1 and d2 are the horizontal projection lengths of the first grouting reinforcement hole 3 and the second grouting reinforcement hole 4 at the designed depth, b1 is the distance between the first grouting reinforcement hole 3 and the first grouting hole 1, b2 is the distance between the second grouting reinforcement hole 4 and the second grouting hole 2, and α1 and α2 are the inclination angles of the first grouting reinforcement hole 3 and the second grouting reinforcement hole 4 on the horizontal plane.

[0020] It should be noted that in the description of the present invention, terms indicating orientation or positional relationships such as "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

Claims

1. A layout method for curtain grouting holes at the axis turning point, characterized in that: Including First step: According to the design value of the bottom line of the curtain grouting and the inclination angle of the grouting holes, calculate the horizontal projection lengths of two adjacent grouting holes on different axes in the plane, and mark them at their ends; Second step: Select two points between the two adjacent grouting holes in the first step as the starting positions of the grouting reinforcement holes. The connection line between the grouting reinforcement holes and the adjacent grouting holes in the plane is a smooth curve; Third step: Connect the end marks of the horizontal projections of the two adjacent grouting holes in the first step with an arc, and divide the arc into three equal parts. The connection line between the starting position of the grouting reinforcement hole and the corresponding trisection point is the horizontal projection of the drilling surface of the grouting reinforcement hole; Fourth step: Drill upstream from the starting position of the grouting reinforcement hole in its drilling surface. The drilling angle is the same as that of the two adjacent grouting holes, and the drilling depth is the average value of the depths of the two adjacent grouting holes.

2. The layout method of the curtain grouting holes at the axis turning points according to claim 1, characterized in that: The grouting holes are arranged with an upward inclination of 3-5° upstream.

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