Construction method of variable-axis vertical shaft in rock mass

Abstract

A construction method of a variable-axis shaft in rock mass relates to underground engineering construction technology, in particular, a method for excavation and support of underground shaft structure. The method constructs a variable-axis shaft including a straight section and a variable-axis section. When the variable-axis section is expanded to the starting position and the ending position, rock benches and outer inclined sections are respectively arranged on the shaft wall at the positions, rock bench locking anchor rods are arranged outside the rock benches, and outer inclined section locking anchor rods are arranged above the outer inclined sections. When excavating, smooth blasting is used for the straight section, smooth blasting is used for the rock bench side, and pre-splitting blasting is used for the outer inclined section. The method has the beneficial effects that the diameter of the straight section of the constructed shaft and the diameter of the variable-axis section do not change, the speed of the slag is reduced by changing the falling trajectory in the variable-axis shaft, energy is lost, and the purpose of energy dissipation is achieved. Moreover, the locking support is arranged on the rock bench and the outer inclined section, the forming quality of the key part of the rock mass is timely protected, and the efficiency of the shaft excavation is improved.

Description

TECHNICAL FIELD

[0001] The application relates to a construction method of a variable-axis type shaft in a rock mass, and particularly relates to a construction method of excavation and support of a shaft structure. BACKGROUND

[0002] At present, the excavation of a shaft is generally carried out by adopting a reverse drilling machine to first construct a guide shaft (generally with a diameter of 1.4-2.5 m) at the center of a pre-excavated shaft, then to expand the diameter to 3.5-4.0 m by a second expansion (by using a cage to expand the diameter from bottom to top), and finally to expand the full section from top to bottom to form a straight shaft. However, when the shaft is used as a slag chute, if the rock strength is low, the shaft bottom and side wall may be subjected to multiple impacts under the action of high potential energy, and thus may be deformed or even damaged, which may affect the safe and stable operation of the chamber to different degrees. Some slag with large particle size may directly impact out of the shaft bottom into the lower tunnel and the expansion area, which may cause great safety hazards to personnel and equipment. SUMMARY

[0003] The application aims to solve the above problems and provides a shaft excavation and support method which can effectively reduce the impact damage energy of a slag chute shaft during the slagging period and control the damage of surrounding rock.

[0004] The application relates to a construction method of a variable-axis type shaft in a rock mass, which comprises the following steps:

[0005] 1) after the guide shaft is formed, the full section of the shaft is expanded from top to bottom, the shaft is excavated into a variable-axis shaft comprising a straight section and a variable-axis section, the axis of the guide shaft is consistent in the straight section and the variable-axis section, and is located at the center of the straight section; when the expansion reaches the starting position of the variable-axis section and the ending position of the variable-axis section, a rock bench and an outer inclined section are arranged on the shaft wall at the positions, rock bench locking anchor rods are arranged outside the rock bench, and outer inclined section locking anchor rods are arranged above the outer inclined section; the rock bench locking anchor rods are 0.5-0.6 m away from the opening of the rock bench, are inclined outward by 10-15 degrees relative to the rock bench, and are arranged at an interval of 0.5-0.8 m; the outer inclined section locking anchor rods are perpendicular to the shaft wall, are arranged 0.5-0.6 m above the starting position of the outer inclined section, and are arranged at an interval of 0.5-0.8 m;

[0006] The rock bench and the outer inclined section are located on the two sides of the axis at the same horizontal plane in the shaft;

[0007] The width L3 of the rock bench is 1.0-1.5 m;

[0008] The length L4 of the outer inclined section is 5-8 m.

[0009] The length L1 of the straight section is 20-30m, and the length L2 of the variable shaft section is 30-50m, and the straight section and the variable shaft section are arranged alternately;

[0010] 2) When excavating, the straight section adopts smooth blasting, and the collapse hole, the main blast hole and the peripheral hole are arranged from the pilot hole outward in sequence, and the detonation sequence is the collapse hole, the main blast hole and the peripheral hole;

[0011] 3) The rock platform side adopts smooth blasting;

[0012] 4) The outer inclined section adopts pre-splitting blasting, and the collapse hole, the main blast hole and the pre-splitting hole are arranged from the pilot hole outward in sequence, and the detonation sequence is the pre-splitting hole, the collapse hole and the main blast hole.

[0013] The collapse hole is 0.3-0.5m away from the edge line of the pilot hole, the hole spacing is 0.3-0.5m, continuous charging is adopted, and the plugging length is 0.6-0.8m.

[0014] The main blast hole is radially arranged along the pilot hole outward, the distance between the adjacent rings is 0.6-1.0m, the spacing increases from the pilot hole outward, continuous charging is adopted, the plugging length is 0.6-0.8m, and the hole spacing is 0.7-1.0m.

[0015] The peripheral hole spacing is 0.4-0.5m, intermittent coupling charging is adopted, and the linear charging density is 75-100g / m.

[0016] The pre-splitting hole spacing is 0.4-0.5m, and the linear charging density is 350-400g / m.

[0017] The rock platform lock hole anchor rod has a length of 2.5-3.5m, an entry of 2.3-3.3m and an exposure of 0.1-0.2m, and is made of a threaded steel bar with a diameter of 25-28.

[0018] The outer inclined section lock hole anchor rod has a length of 2.5-3.5m, an entry of 2.3-3.3m and an exposure of 0.1-0.2m, and is made of a threaded steel bar with a diameter of 25-28.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1) The axis of the pilot hole is consistent in the straight section and the variable shaft section, and is located at the center of the straight section, so that the slag sliding performance of the pilot hole is fully utilized, the pilot hole does not deviate with the change of the section and the amount of slag scraping is large, the excavation and support of the variable shaft section can be efficiently completed, the diameter of the straight section of the built vertical shaft does not change, the speed of the slag is reduced through the change of the falling track in the variable shaft, and the energy is lost, so that the energy dissipation is achieved.

[0021] 2, the mouth of the rock platform and the outer slope segment is set to support the timely protection of the key parts of the rock mass forming quality, improve the vertical shaft excavation efficiency.

[0022] 3, the rock platform side and the outer slope segment side of the variable axis segment are distinguished by using smooth blasting and pre-splitting blasting, even if subjected to multiple blasting disturbances, the damage of surrounding rock is effectively controlled, the rock platform and the outer slope segment are effectively protected, the excavation forming effect is improved, and the safety risk is reduced. The construction of the rock platform and the outer slope segment, part of the slag loses energy by colliding with the residual slag on the rock platform, effectively reduces the impact damage energy of the slag, avoids the strong impact damage of the slag to the vertical shaft side wall and the bottom plate, ensures the safe and stable operation of the chamber, and protects the safety of the construction personnel and equipment. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the present application;

[0024] Figure 2 is a straight segment excavation plane schematic diagram;

[0025] Figure 3 is a variable axis segment starting position excavation plane schematic diagram;

[0026] Figure 4 is an outer slope segment excavation plane schematic diagram;

[0027] Figure 5 is an outer slope segment end position excavation plane schematic diagram;

[0028] Figure 6 is a straight segment excavation blasting hole schematic diagram;

[0029] Figure 7 is a variable axis segment starting position blasting hole schematic diagram;

[0030] Figure 8 is an outer slope segment blasting hole schematic diagram;

[0031] Figure 9 is an outer slope segment end position blasting hole schematic diagram. DETAILED DESCRIPTION

[0032] The present application will be further described below in conjunction with specific embodiments, which are further descriptions of the principles of the present application, and do not limit the present application in any way. The same or similar technology as the present application does not exceed the scope of protection of the present application.

[0033] Referring to Figures 1-5 , a variable axis type vertical shaft construction method in a rock mass, such as Figure 1As shown by the middle arrow, firstly, the lower horizontal tunnel 3 is drilled to the upstream sidewall of the pre-excavated vertical shaft 1, and then the upper horizontal tunnel 2 is drilled to the downstream sidewall of the pre-excavated vertical shaft 1, so that the upper and lower parts of the pre-excavated vertical shaft 1 are fully exposed; using a raise boring machine, a pilot hole 4 with a diameter of 0.25m to 0.3m is constructed from top to bottom at the center position of the pre-excavated vertical shaft 1 as shown by the arrow, and then a pilot shaft 5 with a diameter of 1.4m to 2.5m is constructed from bottom to top as shown by the arrow; the key technology also includes the following steps:

[0034] 1) After the pilot shaft 5 is formed, the vertical shaft 1 is expanded from top to bottom in the direction shown by the arrow. The vertical shaft 1 is excavated according to the design into a variable-axis vertical shaft including a straight section 1.1 and a variable-axis section 1.2. The axis of the pilot shaft 5 is consistent in both the straight section 1.1 and the variable-axis section 1.2, and is located at the exact center of the straight section. When the expansion reaches the starting point AA and the ending point of the variable-axis section, a rock platform 7 and an outer inclined section 8 are respectively set on the shaft wall at these points. A rock platform anchor bolt 9 is set on the outside of the rock platform 7, and an outer inclined section anchor bolt 10 is set above the outer inclined section 8; if Figure 1 , Figure 3 As shown, the rock platform lock anchor 9 is 0.5-0.6m away from the opening of the rock platform, inclined outward at 10-15° to the rock platform, and spaced 0.5-0.8m apart; the outer inclined section lock anchor 10 is perpendicular to the shaft wall, 0.5-0.6m above the starting point of the outer inclined section, and spaced 0.5-0.8m apart.

[0035] 2) such as Figure 6 As shown, during excavation, smooth blasting was used in the straight section 1.1. The guide shaft 5 was used for muck removal. From the guide shaft 5 outwards, caving holes 13, main blasting holes 12, and peripheral holes 11 were arranged sequentially. The caving holes 13 were 0.3–0.5 m from the edge of the guide shaft, with a hole spacing of 0.3–0.5 m, continuously charged, and with a sealing length of 0.6–0.8 m. The main blasting holes 12 radiated outwards in a ring shape along the guide shaft, with a row spacing of 0.6 m–1.0 m from the previous ring. The spacing increased from the inside out of the guide shaft, continuously charged, with a sealing length of 0.6 m–0.8 m and a hole spacing of 0.7 m–1.0 m. The peripheral holes 11 were spaced 0.4 m–0.5 m apart, with intermittent coupled charging and a linear charge density of 75–100 g / m³. The detonation sequence was caving holes 13, main blasting holes 12, and peripheral holes 11.

[0036] 3) such as Figure 7As shown, the rock bench 7 side (the starting part of the variable axis section) uses smooth blasting, and the caving hole 13, the main blast hole 12 and the peripheral hole 11 are arranged outward from the pilot hole 5 in sequence; the caving hole 13 is 0.3-0.5m away from the pilot hole edge line, the hole spacing is 0.3-0.5m, continuous charging, and the plugging length is 0.6-0.8m; the main blast hole 12 is radially arranged in a ring shape outward from the pilot hole, the distance between the upper ring and the interval is 0.6-1.0m, the interval increases outward from the pilot hole, continuous charging, the plugging length is 0.6-0.8m, and the hole spacing is 0.7-1.0m; the peripheral hole 11 has a spacing of 0.4-0.5m, intermittent coupling charging, and the linear charge density is 75-100g / m; the detonation sequence is the caving hole 13, the main blast hole 12 and the peripheral hole 11.

[0037] 4) as shown in Figure 8 、 Figure 9 As shown, the outer inclined section 8 uses pre-splitting blasting, and the caving hole 13, the main blast hole 12 and the pre-splitting hole 14 are arranged outward from the pilot hole 5 in sequence; the caving hole 13 is 0.3-0.5m away from the pilot hole edge line, the hole spacing is 0.3-0.5m, continuous charging, and the plugging length is 0.6-0.8m; the main blast hole 12 is radially arranged in a ring shape outward from the pilot hole, the distance between the upper ring and the interval is 0.6-1.0m, the interval increases outward from the pilot hole, continuous charging, the plugging length is 0.6-0.8m, and the hole spacing is 0.7-1.0m; the pre-splitting hole spacing is 0.4-0.5m, the linear charge density is 350-400g / m; and the detonation sequence is the pre-splitting hole 14→the caving hole 13→the main blast hole 12.

[0038] When the outer inclined section 8 at the end of the variable axis section is constructed, the remaining section is constructed according to the construction method of the straight section.

[0039] The rock bench lock hole anchor rod 9 has a length of 2.5-3.5m, a rock entering length of 2.3-3.3m, and an exposed length of 0.1-0.2m, and is made of a threaded steel bar with a diameter of 25-28.

[0040] The outer inclined section lock hole anchor rod 10 has a length of 2.5-3.5m, a rock entering length of 2.3-3.3m, and an exposed length of 0.1-0.2m, and is made of a threaded steel bar with a diameter of 25-28.

[0041] As shown in Fig. 6, the full-face expansion surface is shown, B-B is the outer inclined section, and C-C is the end of the outer inclined section.

Claims

1. A method for constructing a variable-axis vertical shaft within a rock mass, comprising first penetrating a lower horizontal tunnel (3) to the upstream sidewall of the vertical shaft (1), and then penetrating an upper horizontal tunnel (2) to the downstream sidewall of the vertical shaft (1), thereby exposing the upper and lower parts of the vertical shaft (1); first constructing a pilot hole (4) at the center of the vertical shaft (1), and then constructing a pilot shaft (5); characterized in that... It also includes the following steps: After the pilot shaft (5) is formed, the vertical shaft (1) is excavated from top to bottom across the entire cross section. The vertical shaft (1) is excavated into a variable-axis vertical shaft including a straight section (1.1) and a variable-axis section (1.2). The axis of the pilot shaft (5) is consistent in both the straight section (1.1) and the variable-axis section (1.2), and is located at the exact center of the straight section. When the excavation reaches the starting point (AA) and the ending point of the variable-axis section, the shaft walls at the starting point (AA) and the ending point of the variable-axis section are respectively marked. A rock platform (7) and an outer inclined section (8) are set up. A rock platform locking anchor (9) is set on the outside of the rock platform (7), and an outer inclined section locking anchor (10) is set above the outer inclined section (8). The rock platform locking anchor (9) is 0.5-0.6m away from the opening of the rock platform, inclined outward at 10-15°, and spaced 0.5-0.8m apart. The outer inclined section locking anchor (10) is perpendicular to the shaft wall, 0.5-0.6m above the beginning of the outer inclined section, and spaced 0.5-0.8m apart. During excavation, smooth blasting is used in the straight section (1.1). From the pilot shaft (5) outwards, the collapse hole (13), main blast hole (12) and peripheral hole (11) are arranged in sequence. The detonation sequence is collapse hole (13), main blast hole (12), peripheral hole (11). Smooth blasting was used on the side of the rock platform (7); The outer inclined section (8) adopts pre-splitting blasting. From the pilot shaft (5) outward, the collapse hole (13), the main blast hole (12) and the pre-splitting hole (14) are arranged in sequence. The detonation sequence is pre-splitting hole (14) → collapse hole (13) → main blast hole (12).

2. The method for constructing a variable-axis vertical shaft within a rock mass according to claim 1, characterized in that: The collapse hole (13) is 0.3-0.5m away from the edge of the guide well, the hole spacing is 0.3-0.5m, the explosive charge is continuous, and the plugging length is 0.6-0.8m.

3. The method for constructing a variable-axis vertical shaft within a rock mass according to claim 1, characterized in that the main... The blast holes (12) radiate outward in a ring shape along the guide well, with a spacing of 0.6m to 1.0m between the holes and the previous ring. The spacing increases from the inside to the outside of the guide well. The explosive charge is continuously applied, with a sealing length of 0.6m to 0.8m and a hole spacing of 0.7m to 1.0m.

4. The method for constructing a variable-axis vertical shaft within a rock mass according to claim 1, characterized in that the surrounding... The hole (11) spacing is 0.4m to 0.5m, the explosive is intermittently coupled, and the density of the linear explosive is 75 to 100g / m.

5. The method for constructing a variable-axis vertical shaft within a rock mass according to claim 1, characterized in that: The spacing between pre-cracked holes (14) is 0.4m to 0.5m, and the density of the linear charge is 350m to 400g / m.

6. The method for constructing a variable-axis vertical shaft within a rock mass according to claim 1, characterized in that: The rock platform anchor bolt (9) is 2.5m to 3.5m long, 2.3m to 3.3m into the rock, and 0.1m to 0.2m exposed. It is made of threaded steel bars with a diameter of 25 to 28.

7. The method for constructing a variable-axis vertical shaft within a rock mass according to claim 1, characterized in that: The outer inclined section lock anchor (10) is 2.5-3.5m long, 2.3-3.3m into the rock, and 0.1-0.2m exposed. It is made of threaded steel bars with a diameter of 25-28.

Images