Slope ramp hard rock tunnel core soil reserved excavation construction method

Abstract

The invention discloses a slope ramp hard rock tunnel core soil reserved excavation construction method. The method comprises the following steps that S1, a slope tunnel is divided into N sections in the length direction of the slope tunnel; s2, blasting the tunnel face of the upper step of the first section to reserve hard rock core soil; s2, an upper step is supported; s3, the upper step of the second section continues to be excavated, and meanwhile hard rock core soil is reserved; s4, hard rock core soil and a left middle step are excavated and supported, and a constructor stands on a left lower step for construction operation; s5, excavating a right middle step and supporting; s6, repeating the steps S2-S4 until all the upper steps and the middle steps on the slope tunnel are excavated and supported; s7, a left lower step is excavated and supported; s8, a right lower step is excavated and supported; according to the subway slope section hard rock tunnel construction method, blasting is controlled through shaping, a core rock platform is reserved on an upper platform of a subsurface excavation tunnel, and the problem of a construction operation platform is solved.

Description

Technical Field

[0001] The invention belongs to a dark tunnel excavation construction technology, and in particular relates to a core soil reserved excavation construction method for a ramp hard rock tunnel. Background Art

[0002] For the construction of subway slope section hard rock tunnel, conventional construction methods generally use machinery or ordinary blasting to excavate the tunnel. The construction methods are generally as follows:

[0003] One method is to use a reverse shaft boring machine to dig from the ground to the bottom. The entrance and exit of the subway station of this project is in the central area of ​​the city. The ground location of the entrance and exit is limited and there is no place for the reverse shaft boring machine to operate. In addition, the tunnel curve radius is small (the minimum curve radius R=120), which does not meet the operating conditions for the reverse shaft boring machine.

[0004] One method is to use large equipment such as large breakers and cantilever rock drills to excavate from the inside of the station to the ground. Since the excavation width of the entrance and exit section is 7.2 to 9.4m, the excavation height is 8.4 to 9.6m, and the tunnel centerline has many corners, large equipment cannot excavate at the corners. In addition, the angle between the ramp and the horizontal line is 30°. When large breakers and cantilever rock drills are used for dark excavation on the slope section, the slope surface must slide downward, which makes the operation difficult and the safety risk high. In addition, the tunnel geology is mainly sandstone (natural compressive strength 26 to 42Mpa), and mechanical excavation is difficult.

[0005] Another method is to use drilling and blasting excavation technology, which requires an operating platform. The conventional method is to use a support trolley. Since the angle between the ramp and the horizontal line is 30°, the support trolley is easy to slide down on the ramp and cannot be fixed. Another method is to set up a buckle / ordinary scaffolding pipe operating platform on the slope surface. This method is difficult to set up, inefficient, and personnel are exposed under the rock mass of the unsupported section. The construction safety risk is relatively large, and each cycle bracket installation and removal takes about 5 to 6 hours, which is time-consuming. Summary of the invention

[0006] In order to achieve these purposes and other advantages according to the present invention, a preferred embodiment of the present invention provides a method for core soil reserved excavation construction of a ramp hard rock tunnel, comprising the following steps:

[0007] S1. The slope tunnel is divided into N sections along its length direction, starting from the tunnel entrance, namely the 1st section, the 2nd section, ..... the nth section, ...., the Nth section; the working face of each section of the slope tunnel is divided into upper steps, middle steps and lower steps distributed from top to bottom, the middle steps include the left middle step and the right middle step, and the lower steps include the left lower step and the right lower step;

[0008] S2. Blasting the upper step of the face of the first section of the slope tunnel and reserving hard rock core soil, and supporting the upper step of the first section of the slope tunnel. Construction workers stand on the hard rock core soil of the first section of the slope tunnel to carry out construction work;

[0009] S3. Continue to excavate the upper step of the face of the second section of the slope tunnel, reserve hard rock core soil, and support the upper step of the second section of the slope tunnel. The construction workers stand on the hard rock core soil of the second section of the slope tunnel to carry out construction work;

[0010] S4, excavate the hard rock core soil and the left middle step of the first section of the slope tunnel, and support them. The construction workers stand on the left lower step of the first section of the slope tunnel to carry out construction work;

[0011] S5. Excavate the right middle step of the first section of the slope tunnel and provide support. Construction workers stand on the right lower step of the first section of the slope tunnel to carry out construction work;

[0012] S6, repeat the above S2-S4 until all the upper steps and middle steps on the slope tunnel are excavated;

[0013] S7, excavate the lower left step of the first section of the slope tunnel and provide support, and the construction workers stand on the bottom plate of the first section of the slope tunnel to carry out construction work;

[0014] S8, excavate the lower right step of the first section of the slope tunnel and provide support, and the construction workers stand on the bottom plate of the first section of the slope tunnel to carry out construction work;

[0015] S9. Repeat the above S7-S8 until the slope tunnel is completely excavated.

[0016] In another technical solution, in S2, the upper step of the first section of the slope tunnel is supported, including the following operations: laying steel sections on the inner wall of the tunnel and spraying concrete.

[0017] In another technical solution, the upper surfaces of the left middle step, the right middle step, the left lower step, and the right lower step corresponding to each section of the slope tunnel are all inclined.

[0018] In another technical solution, the inclination angles of the upper surfaces of the left middle step, the right middle step, the left lower step, and the right lower step corresponding to each section of the slope tunnel are all set to enable construction workers to stand.

[0019] In another technical solution, the left middle step and the right middle step corresponding to each section of the slope tunnel have the same height, the lower left step and the lower right step have the same height, and the upper step has the same height as the left middle step and the lower left step.

[0020] In another technical solution, in S2, hard rock core soil is reserved for blasting the face of the first section of the slope tunnel, specifically by excavating blasting holes in the reserved hard rock core soil and transferring explosives to a part of the blasting holes for blasting.

[0021] In another technical solution, the blasting holes are distributed on the tunnel face and are arranged in a circle around the reserved hard rock core soil. The blasting holes include:

[0022] The first auxiliary hole is opened near a circle of reserved hard rock core soil;

[0023] The second auxiliary holes are opened in a circle near the edge of the tunnel face;

[0024] a peripheral eye disposed between the first auxiliary hole and the second auxiliary hole;

[0025] The straight eyelet and the vibration-damping expansion slot are arranged between the first auxiliary hole and the peripheral eye; and the four vibration-damping expansion slots form a square, and one straight eyelet is arranged between the four vibration-damping expansion slots.

[0026] The present invention has at least the following beneficial effects:

[0027] The present invention is aimed at the construction method of subway slope section hard rock tunnel. Through the shaped controlled blasting, the core rock platform is reserved for the dark excavation tunnel, solving the problem of the construction operation platform. This construction method is different from the construction method of reserving core soil under weak surrounding rock. The purpose is to reserve core rock as an artificial operation platform, reduce the construction and dismantling of the operation platform, speed up the construction progress, and achieve obvious social and economic benefits;

[0028] In order to ensure that the core soil of the hard rock tunnel can be reserved, a special blasting design was carried out when blasting and excavating the upper steps, and the straight-eye slotting + vibration reduction holes + micro-error phase vibration reduction blasting construction technology was adopted.

[0029] The specific construction organization of this method is to excavate and support the upper and middle steps in three steps using the short step method. After the upper and middle steps are connected, the lower steps are excavated and supported. This method has the following advantages:

[0030] 1) Construction reduces the installation and disassembly procedures of the working platform and shortens the construction period

[0031] Compared with conventional step blasting, this construction method reduces the number of construction support erection procedures, saves about 5 to 6 hours per cycle, and increases the progress of each cycle by 1 / 4; the excavation and support period for entrances and exits is shortened by 1 / 4.

[0032] 2) Reduce the use of measures and materials, and low construction costs

[0033] This construction method uses core soil as the working platform, eliminating the construction scaffolding process, saving materials used for scaffolding, saving the labor costs of secondary transportation of construction materials on the slope section and scaffolding, and reducing material and labor costs.

[0034] 3) High construction safety

[0035] The one-time excavation height of the slope section is reduced, and the risk factor of personnel working at high altitude is reduced; the scaffolding erection link is reduced. The scaffolding is erected close to the excavation face. There is a risk of falling blocks on the face arch and bare rock surface. Therefore, there is a great safety risk during the scaffolding erection operation period. This construction method can avoid high-risk operations here, speed up the face to enter the support process, complete the excavation and support process as soon as possible, achieve the principle of early closure of support, and better ensure the safety of tunnel construction.

[0036] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a construction schematic diagram of step S2 in the present invention.

[0038] Figure 2 It is a schematic diagram of the construction side of step S3 in the present invention.

[0039] Figure 3 It is a schematic diagram of the construction cross section of step S3 in the present invention.

[0040] Figure 4 It is a schematic side view of the construction of step S6 in the present invention.

[0041] Figure 5 It is a schematic diagram of the construction cross section of step S6 in the present invention.

[0042] Figure 6 It is a schematic side view of the construction of step S7 in the present invention.

[0043] Figure 7 It is a schematic diagram of the construction cross section of step S8 in the present invention.

[0044] Figure 8 It is a schematic diagram of the construction side of step S8 in the present invention.

[0045] Fig. 9 It is a schematic diagram of the distribution of blasting holes in S1 in the present invention. DETAILED DESCRIPTION

[0046] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0047] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0048] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0049] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0050] like Figure 1-9 As shown, a method for core soil reserved excavation construction of a ramp hard rock tunnel of the present invention is characterized by comprising the following steps:

[0051] S1. The slope tunnel is divided into N sections along its length direction, starting from the tunnel entrance, namely the 1st section, the 2nd section, ... the nth section, ..., the Nth section; the working face of each section of the slope tunnel is divided into an upper step 1A, a middle step and a lower step distributed from top to bottom, the middle step includes a left middle step 2A and a right middle step 2B, and the lower step includes a left lower step 3A and a right lower step 3B;

[0052] S2. Blasting the upper step of the tunnel face of the first section of the slope tunnel and reserving hard rock core soil 1C, and supporting the upper step 1A of the first section of the slope tunnel. Construction workers stand on the hard rock core soil of the first section of the slope tunnel to carry out construction work, including erecting frame construction work;

[0053] S3. Continue to excavate the upper step of the face of the second section of the slope tunnel, reserve hard rock core soil, and support the upper step of the second section of the slope tunnel. The construction workers stand on the hard rock core soil of the second section of the slope tunnel to carry out construction work;

[0054] S4, excavate the hard rock core soil and the left middle step 2A of the first section of the slope tunnel, and support them. Then the construction workers stand on the left lower step 3A of the first section of the slope tunnel to carry out construction work;

[0055] S5, excavate the right middle step of the first section of the slope tunnel and support it, then the construction workers stand on the right lower step 3B of the first section of the slope tunnel to carry out construction work;

[0056] S6, repeat the above S2-S4 until all the upper steps and middle steps on the slope tunnel are excavated;

[0057] S7, excavate the lower left step of the first section of the slope tunnel and provide support, and the construction workers stand on the bottom plate of the first section of the slope tunnel to carry out construction work;

[0058] S8, excavate the lower right step of the first section of the slope tunnel and provide support, and the construction workers stand on the bottom plate of the first section of the slope tunnel to carry out construction work;

[0059] S9. Repeat the above S7-S8 until the slope tunnel is completely excavated.

[0060] In the above technical scheme, the upper and middle steps of the entire excavation process are excavated and supported in three steps using the short step method. After the upper and middle steps are connected, the lower steps are excavated and supported. This can reduce the installation and disassembly process of the working platform and shorten the construction period. This construction method reduces the construction support erection process compared to the conventional step blasting method, saving about 5 to 6 hours per cycle, and the progress of each cycle is increased by 1 / 4; the excavation and support period of the entrance and exit is shortened by 1 / 4. Moreover, compared with conventional construction methods, the use of measures materials is reduced and the construction cost is low. This construction method uses core soil as the working platform, eliminates the construction support erection link, and saves the materials used for the support erection, saves the secondary transportation of measures materials in the slope section and the labor cost of the support erection, and reduces the material and labor costs. In addition, the excavation method of the present invention has high construction safety, reduces the one-time excavation height of the slope section, and reduces the risk factor of personnel working at high altitudes; reduces the scaffolding erection link, and the scaffolding erection is close to the excavation face. There is a risk of falling blocks on the face arch and the bare rock surface. Therefore, there is a great safety risk during the scaffolding erection operation period. The construction method can avoid high-risk operations here, speed up the face to enter the support process, complete the excavation and support process as soon as possible, achieve the principle of early closure of support, and better ensure the safety of tunnel construction.

[0061] In another technical solution, in S2, the upper step of the first section of the slope tunnel is supported, including the following operations: laying steel sections on the inner wall of the tunnel and spraying concrete to improve the overall strength and avoid collapse during the construction process.

[0062] In another technical solution, the upper surfaces of the left middle step, the right middle step, the lower left step and the lower right step corresponding to each section of the sloping tunnel are all inclined, and the inclination angles of the upper surfaces of the left middle step, the right middle step, the lower left step and the lower right step corresponding to each section of the sloping tunnel are set so that construction workers can stand, which is convenient for construction workers to work.

[0063] In another technical solution, the left middle step and the right middle step corresponding to each section of the slope tunnel are of the same height, the lower left step and the lower right step are of the same height, and the upper step is of the same height as the left middle step and the lower left step, thereby ensuring overall consistency and facilitating construction.

[0064] In another technical solution, in S2, hard rock core soil is reserved for blasting the face of the first section of the slope tunnel, specifically by excavating blasting holes in the reserved hard rock core soil and transferring explosives to a part of the blasting holes for blasting.

[0065] In another technical solution, the blasting holes are distributed on the tunnel face and are arranged in a circle around the reserved hard rock core soil. The blasting holes include: a first auxiliary hole 3, which is opened in a circle close to the reserved hard rock core soil; a second auxiliary hole 4, which is opened in a circle close to the edge of the tunnel face; a peripheral hole 5, which is arranged between the first auxiliary hole 3 and the second auxiliary hole 4; the straight eyelet groove 1 and the vibration-damping expansion groove hole 2 are arranged between the first auxiliary hole 3 and the peripheral hole 5; and, four of the vibration-damping expansion groove holes 2 form a square, and one straight eyelet groove 1 is arranged between the four vibration-damping expansion groove holes 2.

[0066] This method adjusts the blasting design and adopts shaped controlled blasting to achieve the reserved core rock platform and low-speed blasting on the dark excavation tunnel, solving the problems of difficult support construction operation platform setting and high blasting vibration speed in the excavation of hard rock tunnels in the slope section of the subway. Compared with mechanical excavation or ordinary blasting excavation, this method reduces the construction and dismantling of the working platform, speeds up the construction progress, and reduces the erection of the buckle bracket by about 5 hours per cycle, and increases the progress of each cycle by 1 / 3.

[0067] Taking a 300m long entrance and exit as an example, a sub-unit project shortened the construction period by 4.5 months, saved 1,620 man-days of labor, saved 135 shifts of CAT150 crawler excavators, 135 shifts of tire loaders, and 135 shifts of double-axle dump trucks for entrance and exit operations; one entrance and exit saved 660,266 yuan in direct construction costs, and there were 16 similar entrances and exits in the Chongqing Rail Transit Line 18 North Extension Project, with a total cost saving of 16×660,266=10,564,256 yuan; coupled with the shortened construction period and reduced management fees, the project cost was further reduced; this construction method has a high economic benefit.

[0068] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for core soil reserved excavation construction of a ramp hard rock tunnel, characterized in that: The following steps are involved: S1. The slope tunnel is divided into N sections along its length direction, starting from the tunnel entrance, namely the 1st section, the 2nd section, ..... the nth section, ...., the Nth section; the working face of each section of the slope tunnel is divided into upper steps, middle steps and lower steps distributed from top to bottom, the middle steps include the left middle step and the right middle step, and the lower steps include the left lower step and the right lower step; S2. Blasting the upper step of the face of the first section of the slope tunnel and reserving hard rock core soil, and supporting the upper step of the first section of the slope tunnel. Construction workers stand on the hard rock core soil of the first section of the slope tunnel to carry out construction work; S3. Continue to excavate the upper step of the face of the second section of the slope tunnel, reserve hard rock core soil, and support the upper step of the second section of the slope tunnel. The construction workers stand on the hard rock core soil of the second section of the slope tunnel to carry out construction work; S4, excavate the hard rock core soil and the left middle step of the first section of the slope tunnel, and support them. The construction workers stand on the left lower step of the first section of the slope tunnel to carry out construction work; S5. Excavate the right middle step of the first section of the slope tunnel and provide support. Construction workers stand on the right lower step of the first section of the slope tunnel to carry out construction work; S6, repeat the above S2-S4 until all the upper steps and middle steps on the slope tunnel are excavated; S7, excavate the lower left step of the first section of the slope tunnel and provide support, and the construction workers stand on the bottom plate of the first section of the slope tunnel to carry out construction work; S8, excavate the lower right step of the first section of the slope tunnel and provide support, and the construction workers stand on the bottom plate of the first section of the slope tunnel to carry out construction work; S9. Repeat the above S7-S8 until the slope tunnel is completely excavated.

2. The method for core soil reserved excavation of a ramp hard rock tunnel according to claim 1 is characterized in that: In S2, the upper step of the first section of the slope tunnel is supported, including the following operations: laying steel sections on the inner wall of the tunnel and spraying concrete.

3. The method for core soil reserved excavation of a ramp hard rock tunnel according to claim 1 is characterized in that: The upper surfaces of the left middle step, the right middle step, the left lower step and the right lower step corresponding to each section of the slope tunnel are all inclined.

4. The method for core soil reserved excavation of a ramp hard rock tunnel according to claim 3 is characterized in that: The inclination angles of the upper surfaces of the left middle step, the right middle step, the left lower step, and the right lower step corresponding to each section of the slope tunnel are all set to enable construction workers to stand.

5. The method for core soil reserved excavation of a ramp hard rock tunnel according to claim 3 is characterized in that: The left middle step and the right middle step corresponding to each section of the slope tunnel have the same height, the left lower step and the right lower step have the same height, and the upper step has the same height as the left middle step and the left lower step.

6. The method for core soil reserved excavation of a ramp hard rock tunnel according to claim 1 is characterized in that: In S2, the hard rock core soil is reserved for blasting the face of the first section of the slope tunnel, specifically by excavating blasting holes in the reserved hard rock core soil and transferring explosives to a part of the blasting holes for blasting.

7. The method for core soil reserved excavation of a ramp hard rock tunnel according to claim 6 is characterized in that: The blasting holes are distributed on the tunnel face and are arranged in a circle around the reserved hard rock core soil. The blasting holes include: The first auxiliary hole is opened near a circle of reserved hard rock core soil; The second auxiliary holes are opened in a circle near the edge of the tunnel face; a peripheral eye disposed between the first auxiliary hole and the second auxiliary hole; The straight eyelet and the vibration-damping expansion slot are arranged between the first auxiliary hole and the peripheral eye; and the four vibration-damping expansion slots form a square, and one straight eyelet is arranged between the four vibration-damping expansion slots.

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