CN115030754A

CN115030754A - Mine-method underground tunnel waterproof curtain and construction method

Info

Publication number: CN115030754A
Application number: CN202210683469.4A
Authority: CN
Inventors: 黄怀宁; 侯宇迪; 惠丽萍; 薛茹镜; 李名淦
Original assignee: Beijing General Municipal Engineering Design and Research Institute Co Ltd
Current assignee: Beijing General Municipal Engineering Design and Research Institute Co Ltd
Priority date: 2022-06-17
Filing date: 2022-06-17
Publication date: 2022-09-09

Abstract

A mine underground tunnel waterproof curtain and a construction method are provided, wherein the construction method comprises the following steps: excavating and penetrating No. 1 and No. 2 cavities on the upper layer of the underground water level to apply a primary support structure; grouting downwards at two outer bottom corners of the No. 1 and No. 2 through caverns to form grouting extending into a water-proof stratum to a certain depth to serve as a two-side wall type waterproof curtain; constructing a transverse grouting body from an upper-layer cavern in a direction perpendicular to the excavation direction at a certain distance from the front of the tunnel face, and entering a water-proof stratum to a certain depth to serve as a transverse wall type water-stopping curtain which is closed with the two side wall type water-stopping curtains; draining groundwater within the range of the waterproof curtain; excavating No. 3 and No. 4 caverns in the underground water to the front of the transverse waterproof curtain; and repeating the construction circulation of 'forming a transverse waterproof curtain, pumping and draining underground water and excavating the cavern' until the 3 or 4 caverns in the underground water are communicated. Compared with the full-section grouting mode, the water stopping construction method reduces a part of unnecessary grouting amount.

Description

Mine-method underground tunnel waterproof curtain and construction method

Technical Field

The invention relates to the technical field of waterproof curtain structures for underground water stop treatment in underground tunnel engineering, in particular to a mine underground tunnel waterproof curtain and a construction method; the waterproof curtain structure and the construction method can be applied to underground tunnel excavation by a mining method.

Background

At present, in the underground tunnel construction process by adopting a mining method, particularly under the condition of a soil stratum, the excavation operation is generally required to be carried out under a waterless state for the consideration of excavation construction safety. Therefore, when the underground tunnel cross section enters the ground water level, the ground water must be treated first. There are two main ways of treating groundwater, precipitation and water stop. The precipitation is generally to pump water through setting up precipitation well, falls the tunnel excavation scope local ground water level below excavation section position. The water stopping is generally realized by forming a water stopping curtain with a certain thickness outside the excavation contour line of the tunnel, preventing underground water from entering the excavation range and performing excavation construction under the obstruction of the water stopping curtain. Precipitation is relatively wasteful of water resources and causes ground settlement risks, often being restricted in use in cities.

The former waterproof curtain is generally formed by underground continuous walls, occlusive piles, jet grouting piles, full-section grouting and the like. Common construction machinery of underground continuous walls, secant piles and jet grouting piles is tall and big, is generally used for open cut construction, and is not suitable for underground tunnel engineering with a mine method with limited space. In recent years, although the use of a specially designed miniaturized machine in a mine-method pilot hole is realized, the pilot hole is generally required to be additionally arranged outside a tunnel section for waterproof curtain construction, so that redundant excavation engineering is generated, the excavation section is widened, and the mine-method construction risk is increased. The full-section grouting is a water-stop curtain form which is more common in underground tunnel engineering of a mine method, and is carried out on a tunnel section entering underground water, so that the slurry extrudes the underground water out of an excavation area, the impermeability coefficient of a soil layer is improved, and a water-resisting layer with a certain thickness is formed outside an excavation contour line. The waterproof curtain slip casting work volume of full section slip casting form is very big, and is the effective water barrier of reality except excavation profile line border, and all the other inside slip casting body are the slip casting that does not have the stagnant water purpose, all are excavated at the excavation in-process, and the cost is higher and there is great waste.

Disclosure of Invention

Aiming at the problems, the waterproof curtain for the underground tunnel by the mining method and the construction method are provided, and the technical problems that the grouting engineering quantity of the waterproof curtain in the full-section grouting mode for the underground tunnel by the mining method is large, the periphery of an excavation contour line is an actual effective waterproof layer, other inner grouting bodies are grouting bodies without the waterproof purpose, the grouting bodies are all excavated in the excavation process, the manufacturing cost is high, and great waste exists are solved.

The technical scheme of the invention is as follows:

the invention discloses a construction method of a mine underground tunnel waterproof curtain, which is characterized by comprising the following steps of:

excavating and penetrating an upper-layer No. 1 cavern 301 and a No. 2 cavern 302 which are positioned at an underground water level, and synchronously constructing a primary support structure of the cavern;

after the upper layer 1 and the upper layer 2 caverns are communicated, grouting downwards at bottom corners of two outer sides of the communicated caverns to form a grouting body which has a certain thickness and extends into the water-proof stratum 1 by a certain depth to serve as a two-side wall type water-stop curtain 201;

step three, applying a transverse grouting body with the same thickness from the upper cavity to the excavation direction and perpendicular to the excavation direction at a certain distance from the front of the tunnel face, and enabling the transverse grouting body to enter a water-proof stratum 1 for a certain depth to serve as a transverse wall type water-stopping curtain 202 which is closed with the wall type water-stopping curtains 201 on the two sides in the previous step; draining groundwater within the range of the waterproof curtain; excavating a No. 3 cavern 401 and a No. 4 cavern 402 in underground water to the front of a transverse waterproof curtain; step (IV), repeating the construction cycle of grouting to form a transverse waterproof curtain, pumping underground water and excavating a cavern in the step (III) until the construction cycle is communicated with No. 3 and No. 4 caverns in the underground water; and (5) dismantling the primary support in sections, paving a waterproof plate, and pouring a permanent secondary lining structure.

The method for constructing the waterproof curtain of the underground tunnel by the mine method comprises the following steps of (I), positioning a cavity 1 and a cavity 2 on the upper layer above an underground water level, reserving core soil when excavating the cavity 301 1 of a pilot tunnel, staggering the upper step and the lower step by 3-5m when excavating by the step method, erecting a steel grating, reinforcing arch springs by adopting locking anchor rods, spraying primary support concrete by hanging nets, and timely constructing a primary support I on the upper layer and grouting the back; after the No. 1 cavern is communicated, excavating a No. 2 cavern 302 of an upper guide tunnel parallel to the No. 1 cavern by the same method, and applying an upper primary support II and back grouting until the No. 2 cavern is communicated; an upper temporary intermediate wall 32 is arranged between the No. 1 cavern and the No. 2 cavern; and an upper temporary inverted arch 33 is constructed at the bottom of the upper pilot tunnel.

The mine method underground tunnel waterproof curtain construction method comprises the following steps that an upper primary support I and an upper primary support II form an upper primary support 31.

The construction method of the underground tunnel waterproof curtain by the mine method is characterized in that in the step (three), the transverse wall type waterproof curtain 202 and the two side wall type waterproof curtains 201 are closed to form a closed vertical wall type waterproof curtain 2, and then underground water in the range of the closed vertical wall type waterproof curtain is pumped out; in the closed vertical wall type waterproof curtain 2, a No. 3 cavern 401 is excavated firstly, core soil is reserved, the upper step and the lower step are staggered by 3-5m during excavation by a step method, a steel grating is erected, a locking anchor rod is adopted to reinforce an arch foot, a net is hung to spray primary support concrete, and the third primary support and the back grouting of the lower layer are constructed in time; when the No. 3 chamber advances by 5-7m, excavating the No. 4 chamber 402 which is parallel to the No. 3 chamber, applying the fourth lower-layer primary support and back grouting until the No. 3 chamber and the No. 4 chamber are excavated to the front of the transverse waterproof curtain 202; a lower temporary intermediate wall 42 is arranged between the No. 3 cavern and the No. 4 cavern.

The construction method of the underground tunnel waterproof curtain by the mining method is characterized in that the step (IV) of grouting to form the transverse waterproof curtain, pumping and draining the underground water and excavating the cavern is a construction step of repeating the step (III) for multiple times.

The construction method of the underground tunnel waterproof curtain by the mining method comprises the following steps that (IV), after a primary support tunnel chamber is communicated, the bottom of a lower temporary middle partition wall is cut off by a section of 5-7m, a tunnel inverted arch waterproof layer is constructed on a lower temporary inverted arch, an inverted arch secondary lining is poured, and a steel bar and waterproof plate joint is reserved; and cutting off a section of 5-7m, removing the residual upper and lower temporary middle bulkheads and upper temporary inverted arches, constructing an arch part and a side wall waterproof layer, pouring a secondary lining structure, sealing to form a ring, and performing secondary lining back grouting in time.

The mine method underground tunnel waterproof curtain is a closed vertical wall type waterproof curtain 2 and comprises a two-side wall type waterproof curtain 201 and a transverse wall type waterproof curtain 202 which are connected in a closed mode; the upper layer pilot tunnel area is a reinforced stratum, an arch-shaped cavern is formed when the upper layer pilot tunnel is positioned above the underground water level, the two side wall type waterproof curtains 201 are arranged downwards and penetrate through the two outer bottom corners of the upper layer pilot tunnel cavern, the bottom of the waterproof curtain enters a waterproof stratum 1 to a certain depth, and the waterproof stratum 1 is a stratum which naturally exists below the underground water level and has a low seepage coefficient; and a transverse wall type waterproof curtain 202 which is arranged transversely from the upper cavity in the same thickness and enters the waterproof stratum 1 by a certain depth is arranged in the same thickness direction, and is connected with the wall type waterproof curtains on the two sides into a whole to form the closed vertical wall type waterproof curtain 2.

The mine method underground tunnel waterproof curtain is characterized in that the two side wall type waterproof curtains 201 and the transverse wall type waterproof curtain 202 are grouting bodies.

The mine method underground tunnel waterproof curtain is characterized in that a plurality of transverse wall type waterproof curtains are arranged at intervals.

The mine underground tunnel waterproof curtain is characterized in that a lower-layer pilot tunnel 4 is arranged below an upper-layer pilot tunnel 3 in the area of the tunnel waterproof curtain; and constructing a tunnel structure in the upper and lower guide holes.

According to the invention, for the mine-method tunnel only allowing the lower section to enter the underground water, a certain range is excavated along two sides of the side wall contour line of the section in a grouting mode by utilizing the upper space of the tunnel not entering the underground water, grouting is vertically performed downwards until the grouting body enters the water-resisting layer, and vertical wall type water-stopping curtains are formed on two sides of the excavated section. And underground water in the tunnel is drained while a lower guide tunnel is excavated through the separation of transverse and longitudinal waterproof curtains to form a tunnel section. When the water stopping construction is achieved, compared with a full-section grouting mode, a part of unnecessary grouting amount is reduced.

Effects of the invention

According to the invention, by utilizing the upper space without entering underground water, a certain range is excavated along the two sides of the side wall contour line of the section in a grouting manner, and grouting is vertically performed downwards until the grouting body enters the water-resisting layer, so that vertical wall type waterproof curtains are formed on the two sides of the excavated section. And underground water in the tunnel is drained while a lower guide tunnel is excavated through the separation of transverse and longitudinal waterproof curtains to form a tunnel section. When the water stopping construction is achieved, compared with a full-section grouting mode, a part of unnecessary grouting amount is reduced.

Drawings

FIG. 1 is a schematic diagram of the step sequence of cross-section construction of step (I) of the present invention,

FIG. 2 is a schematic diagram of the cross-sectional construction process of step (II) of the present invention,

FIG. 3 is a schematic diagram of the step sequence of the step (III) of the construction of the vertical section,

figure 4 is a schematic view of the horizontal cross-section construction process of figure 3,

FIG. 5 is a schematic diagram of the step sequence of the construction of the vertical section in the step (III) of the present invention,

figure 6 is a schematic view of the horizontal cross-section construction process of figure 5,

FIG. 7 is a schematic diagram of the step sequence of the step (III) of the construction of the vertical section,

figure 8 is a schematic view of the horizontal cross-section construction process of figure 7,

figure 9 is a schematic view of the cross-sectional construction process of figure 7,

FIG. 10 is a schematic view of the construction process of the cross section of step (IV) of the present invention,

description of the figure numbering:

the waterproof structure comprises a waterproof stratum 1, a closed vertical wall type waterproof curtain 2, two side wall type waterproof curtains 201, a transverse wall type waterproof curtain 202, an upper layer pilot tunnel 3, a No. 1 cavern 301, a No. 2 cavern 302, an upper layer primary support 31, an upper layer temporary intermediate wall 32, an upper layer temporary inverted arch 33, a lower layer pilot tunnel 4, a No. 3 cavern 401, a No. 4 cavern 402, a lower layer primary support 41, a lower layer temporary intermediate wall 42 and a permanent secondary lining 5.

Detailed Description

For a clearer understanding of the technical solutions of the present invention, the following detailed descriptions of specific embodiments of the present invention are provided with reference to the accompanying drawings.

Referring to fig. 1-10, the invention discloses a construction method of a waterproof curtain of an underground tunnel by a mine method, which is characterized by comprising the following steps:

excavating and penetrating an upper-layer No. 1 cavern 301 and a No. 2 cavern 302 positioned in an underground water level, and synchronously constructing primary support structures of the chambers; referring to fig. 1, the groundwater level is below the bottoms of the No. 1 cavern 301 and the No. 2 cavern 302;

after the upper-layer cavern 1 and the upper-layer cavern 2 are communicated, grouting downwards at bottom corners of two outer sides of the communicated cavern to form a grouting body which has a certain thickness and extends into the water-proof stratum 1 to a certain depth and serves as a two-side wall type water-stopping curtain 201; as shown with reference to figure 2 of the drawings,

step three, as shown in fig. 3 and 4, a transverse grouting body is made from the upper-layer cavern in a certain distance from the front of the tunnel face and in a direction perpendicular to the excavation direction and with the same thickness, enters the water-proof stratum 1 for a certain depth, serves as a transverse wall type water-stopping curtain 202, and is closed with the two side wall type water-stopping curtains 201 in the previous step; referring to fig. 5 and 6, groundwater within the range of the waterproof curtain is pumped out; referring to fig. 7, 8 and 9, excavating a No. 3 chamber 401 and a No. 4 chamber 402 in underground water to the front of a transverse waterproof curtain;

step (four), repeating the construction cycle of 'grouting to form a transverse waterproof curtain, pumping and draining underground water and excavating a cavern' in the step (three) until the construction cycle is communicated with No. 3 and No. 4 caverns in the underground water; and (5) dismantling the primary support in sections, paving a waterproof plate, and pouring a permanent secondary lining structure. As shown with reference to figure 10 of the drawings,

the construction method of the underground tunnel waterproof curtain by the mine method comprises the following steps of (I), positioning an upper layer cavity 1 and a cavity 2 above an underground water level, reserving core soil when the cavity 1 of a pilot tunnel is excavated, staggering upper and lower steps for 3-5m when the cavity 1 of the pilot tunnel is excavated by a step method, erecting a steel grating, reinforcing arch legs by adopting foot locking anchor rods, spraying primary support concrete by using a hanging net, and timely performing first-stage support construction and back grouting on the upper layer; after the No. 1 cavern is communicated, excavating a No. 2 cavern 302 of an upper guide tunnel parallel to the No. 1 cavern by the same method, and applying an upper primary support II and back grouting until the No. 2 cavern is communicated; an upper temporary intermediate wall 32 is arranged between the No. 1 cavern and the No. 2 cavern; constructing an upper temporary inverted arch 33 at the bottom of the upper pilot tunnel; see fig. 1.

The underground tunnel waterproof curtain construction method by the mine method is characterized in that in the step (III), the transverse wall type waterproof curtain 202 and the two side wall type waterproof curtains 201 are closed to form a closed vertical wall type waterproof curtain 2, and then underground water in the range of the closed vertical wall type waterproof curtain is pumped out; in the closed vertical wall type waterproof curtain 2, a No. 3 cavern 401 is excavated firstly, core soil is reserved, the upper step and the lower step are staggered by 3-5m during excavation by a step method, a steel grating is erected, a locking anchor rod is adopted to reinforce an arch foot, a net is hung to spray primary support concrete, and the third primary support and the back grouting of the lower layer are constructed in time; when the No. 3 chamber advances by 5-7m, excavating the No. 4 chamber 402 which is parallel to the No. 3 chamber, applying the fourth lower-layer primary support and back grouting until the No. 3 chamber and the No. 4 chamber are excavated to the front of the transverse waterproof curtain 202; a lower temporary intermediate wall 42 is arranged between the No. 3 cavern and the No. 4 cavern; see fig. 8.

The construction method of the underground tunnel waterproof curtain by the mining method comprises the following steps that (IV), after a primary support tunnel chamber is communicated, the bottom of a lower temporary middle partition wall is cut off by a section of 5-7m, a tunnel inverted arch waterproof layer is constructed on a lower temporary inverted arch, an inverted arch secondary lining is poured, and a steel bar and waterproof plate joint is reserved; and cutting off a section of 5-7m, removing the residual upper and lower temporary middle bulkheads and upper temporary inverted arches, constructing arch parts and side wall waterproof layers, pouring a secondary lining structure, sealing to form a ring, and timely performing secondary lining back grouting, as shown in figure 10.

The mine method underground tunnel waterproof curtain is a closed vertical wall type waterproof curtain 2 and comprises a two-side wall type waterproof curtain 201 and a transverse wall type waterproof curtain 202 which are connected in a closed mode; the upper pilot tunnel area is a reinforced stratum, an arch-shaped cavern is formed when the upper pilot tunnel is positioned above the underground water level, the two side wall type waterproof curtains 201 are arranged downwards by penetrating through two outer side bottom corners of the upper pilot tunnel cavern, the bottom of the waterproof curtain enters a waterproof stratum 1 to a certain depth, and the waterproof stratum 1 is a naturally-existing stratum with a low seepage coefficient below the underground water level; and a transverse wall type waterproof curtain 202 which is arranged transversely from the upper cavity in the same thickness and enters the waterproof stratum 1 by a certain depth is arranged in the same thickness direction, and is connected with the wall type waterproof curtains on the two sides into a whole to form the closed vertical wall type waterproof curtain 2. See fig. 2, 3, 4.

The underground tunnel waterproof curtain adopting the mining method is characterized in that a lower-layer pilot tunnel 4 is arranged below an upper-layer pilot tunnel 3 in the area of the underground tunnel waterproof curtain; and (3) constructing a tunnel structure in the upper and lower guide holes, as shown in figures 9 and 10.

Claims

1. A construction method of a mine underground tunnel waterproof curtain is characterized by comprising the following steps:

excavating and penetrating an upper-layer No. 1 cavern (301) and a No. 2 cavern (302) which are positioned at an underground water level, and synchronously constructing a primary support structure of the cavern;

after the upper-layer cavern 1 and the upper-layer cavern 2 are communicated, grouting downwards at bottom corners of two outer sides of the communicated cavern to form a grouting body with a certain thickness and extending into the water-proof stratum (1) to a certain depth, and using the grouting body as a two-side wall type water-stop curtain (201);

step three, at a certain distance from the front of the tunnel face, applying a transverse grouting body with the same thickness from the upper-layer cavern to the excavation direction, and entering the water-proof stratum (1) for a certain depth to serve as a transverse wall type water-stopping curtain (202) to be closed with the two side wall type water-stopping curtain (201) in the previous step; draining groundwater within the range of the waterproof curtain; excavating a No. 3 cavern (401) and a No. 4 cavern (402) in underground water to the front of a transverse waterproof curtain;

step (four), repeating the construction cycle of 'grouting to form a transverse waterproof curtain, pumping and draining underground water and excavating a cavern' in the step (three) until the construction cycle is communicated with No. 3 and No. 4 caverns in the underground water; and (5) dismantling the primary support in sections, paving a waterproof plate, and pouring a permanent secondary lining structure.

2. The method for constructing the waterproof curtain of the underground tunnel by the mining method according to claim 1, wherein in the step (one), the No. 1 chamber and the No. 2 chamber on the upper layer are positioned above the underground water level, core soil is reserved when the No. 1 chamber (301) of the pilot tunnel is excavated, the upper step and the lower step are staggered by 3-5m when the step method is excavated, a steel grating is erected, a locking anchor rod is adopted to reinforce an arch foot, primary support concrete is sprayed by a hanging net, and primary support one and back grouting on the upper layer are constructed in time; after the No. 1 cavern is communicated, a No. 2 cavern (302) of an upper guide tunnel parallel to the No. 1 cavern is excavated by the same method, and an upper primary support II and back grouting are applied until the No. 2 cavern is communicated; an upper temporary intermediate wall (32) is arranged between the No. 1 cavern and the No. 2 cavern; an upper temporary inverted arch (33) is constructed at the bottom of the upper pilot tunnel.

3. The method for constructing a waterproof curtain for an underground tunnel by a mining method according to claim 2, wherein the first upper primary support and the second upper primary support form an upper primary support (31).

4. The method for constructing a waterproof curtain for an underground tunnel by a mining method according to claim 1, wherein in the step (three), the transverse wall type waterproof curtain (202) is closed with the two side wall type waterproof curtains (201) to form the closed vertical wall type waterproof curtain (2), and then underground water in the range of the closed vertical wall type waterproof curtain is drained; in the closed vertical wall type waterproof curtain (2), firstly, a No. 3 grotto (401) is excavated, core soil is reserved, the upper step and the lower step are staggered by 3-5m during excavation by a step method, a steel grating is erected, a foot-locking anchor rod is adopted to reinforce an arch foot, a net is hung to spray primary support concrete, and the third primary support and the back grouting of the lower layer are constructed in time; when the No. 3 chamber advances by 5-7m, excavating the No. 4 chamber (402) which is parallel to the No. 3 chamber, applying the fourth primary support and the back grouting of the lower layer until the No. 3 chamber and the No. 4 chamber are excavated to the front of the transverse waterproof curtain (202); a lower temporary intermediate wall (42) is arranged between the No. 3 cavern and the No. 4 cavern.

5. The mining underground tunnel waterproof curtain construction method according to claim 1, wherein the grouting to form the transverse waterproof curtain-pumping underground water-excavating the cavern in the step (four) is a construction step of repeating the step (three) for multiple times.

6. The method for constructing the waterproof curtain of the underground tunnel by the mining method according to claim 1, wherein in the step (four), after the primary branch cavern is communicated, the bottom of the lower temporary middle partition wall is cut off by a section of 5-7m, a waterproof layer of an inverted arch of the tunnel is constructed on the lower temporary inverted arch, a second lining of the inverted arch is poured, and a joint of a steel bar and a waterproof board is reserved; and cutting off a section of 5-7m, removing the residual upper and lower temporary middle bulkheads and upper temporary inverted arches, constructing an arch part and a side wall waterproof layer, pouring a secondary lining structure, sealing to form a ring, and performing secondary lining back grouting in time.

7. The mining underground tunnel waterproof curtain of claim 1, which is a closed vertical wall waterproof curtain (2) and comprises two side wall waterproof curtains (201) and a transverse wall waterproof curtain (202) which are connected in a closed mode; the upper layer pilot tunnel area is a reinforced stratum, an arch-shaped cavern is formed when the upper layer pilot tunnel is positioned above the underground water level, the two side wall type waterproof curtains (201) are arranged downwards and penetrate through the bottom corners of the two outer sides of the upper layer pilot tunnel cavern, the bottom of the upper layer pilot tunnel cavern enters a water-proof stratum (1) to a certain depth, and the water-proof stratum (1) is a stratum which naturally exists below the underground water level and has a low seepage coefficient; and a transverse wall type waterproof curtain (202) which is arranged transversely from the upper-layer cavern in the same thickness and enters the waterproof stratum (1) with a certain depth is arranged in the direction perpendicular to the excavation direction, and is connected with the two side wall type waterproof curtains into a whole to form the closed vertical wall type waterproof curtain (2).

8. The minery underground tunnel waterproof curtain of claim 7, wherein the two side wall type waterproof curtains (201) and the transverse wall type waterproof curtain (202) are grouting bodies.

9. The mine underground tunnel waterproof curtain of claim 7, wherein the transverse wall type waterproof curtain is spaced a plurality of times.

10. The minemethod underground tunnel waterproof curtain of claim 7, wherein a lower guide hole (4) is arranged below an upper guide hole (3) in the area inside the tunnel waterproof curtain; and constructing a tunnel structure in the upper and lower guide holes.