Safe construction and deformation monitoring method of tunnels through inclined rock formations in pumped storage power stations

Abstract

The present invention relates to the technical field of pumped-storage power stations, and specifically to a method for safe construction and deformation monitoring of a tunnel that passes through an inclined rock formation in a pumped-storage power station; the starting port of the tunnel construction is set on the low-inclination side, and the exit is set on the high-inclination side; a combined steel ring is used to support the excavated rock formation layer, wherein the inclined steel ring is set at an angle and its inclination direction is consistent with the inclination direction of the inclined rock formation and completely covers the rock formation layer, and the combined positive steel ring is perpendicular to the axis of the tunnel; the inclined steel ring is used to reduce the uneven displacement between the inclined rock formations, and the combined positive steel ring can improve the strength and supporting capacity of the inclined steel ring. The present invention first constructs a large-diameter tunnel, and then sets a tunnel for actual water flow inside it, and constructs a gravel buffer layer between the two. The gravel buffer layer can dilute the uneven creep of the inclined rock formation and reduce the displacement difference between the steel sleeves. Later, corrective measures can be taken according to the actual displacement monitoring situation.

Description

Technical Field

[0001] The present invention relates to the technical field of pumped storage power stations, and in particular to a method for safe construction and deformation monitoring of a tunnel passing through an inclined rock layer in a pumped storage power station. Background Art

[0002] A pumped-storage power station primarily consists of an upper reservoir, a lower reservoir, and a tunnel connecting the two. Water from the lower reservoir is pumped to the upper reservoir using electricity generated during off-peak periods. During peak periods, water is released from the upper reservoir to the lower reservoir for power generation. The upper and lower reservoirs of a pumped-storage power station are typically constructed within naturally formed valleys or abandoned open-pit mines, thus reducing the construction workload associated with the reservoirs. Once the locations of the upper and lower reservoirs are determined, the location of the connecting tunnel is significantly limited. Some tunnels may need to traverse entire small peaks or hillocks. Due to geological activity, many rock formations have inclined dips. Tunnel construction along the dip direction of these strata is susceptible to geological risks. Specifically, due to varying lithology, including density and strength, adjacent strata can experience uneven creep displacement into the tunnel, resulting in uneven axial variations in tunnel cross-sectional dimensions. This can damage tunnel support and create safety hazards. Summary of the Invention

[0003] In response to the above technical problems, the present invention proposes a method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations. The pumped storage power station tunnel is constructed along the inclination direction, comprising the following steps:

[0004] a. The starting point of the tunnel construction should be set on the low-inclination side, and the exit should be set on the high-inclination side;

[0005] b. Excavate the tunnel from the starting point toward the exit. After each complete excavation of a rock layer, use a combination of steel rings to support the excavated complete rock layer. The combination of steel rings includes an inclined steel ring and a combined positive steel ring. Both the inclined steel ring and the combined positive steel ring are circular steel rings with a certain width. The inclined steel ring is arranged at an angle, and its inclination direction is consistent with the inclination direction of the inclined rock layer, and completely covers the excavated complete rock layer. The combined positive steel ring is perpendicular to the axis of the tunnel. The inclined steel ring and the combined positive steel ring are connected and fixed at the horizontal bisector of the tunnel.

[0006] c. Filling the lower portion of the tunnel with crushed stone, and then laying an anti-deformation steel sleeve on top of the crushed stone. The anti-deformation steel sleeve comprises several steel sleeve sections, with adjacent steel sleeves connected by bellows; the axial centerline of the anti-deformation steel sleeve is parallel to the axial centerline of the tunnel; filling the space between the tunnel and the anti-deformation steel sleeve with crushed stone to form a crushed stone buffer layer; sealing the annular space between the tunnel and the anti-deformation steel sleeve at the starting point and the exit, thereby sealing the crushed stone buffer layer;

[0007] d. A displacement monitoring device is installed on each section of the steel sleeve to monitor the displacement changes of each section of the steel sleeve.

[0008] Preferably, in step b, the inclined steel ring and the combined straight steel ring are integrally formed.

[0009] Preferably, in step b, independent positive steel rings are used for support at the starting port and the exit, wherein the independent positive steel ring is a circular steel ring having a certain width, and the independent positive steel ring is perpendicular to the axis of the tunnel.

[0010] Preferably, in step b, connecting bars are used to connect adjacent independent positive steel rings and combined steel rings, and combined steel rings and combined steel rings, and concrete is sprayed to cover the tunnel excavation wall and the independent positive steel rings and combined steel rings.

[0011] Preferably, in step b, if the positions of the independent positive steel ring and the combined steel ring overlap at the starting port and the exit, the independent positive steel ring and the combined steel ring are fixedly connected together.

[0012] Preferably, in step c, reinforcing ribs are welded to the outer wall of the steel sleeve, and the reinforcing ribs include axial reinforcing ribs and annular reinforcing ribs that are crisscrossed.

[0013] Preferably, in step c, the anti-deformation steel sleeve is eccentrically arranged downward in the tunnel.

[0014] Preferably, in step d, when the displacement change difference between two adjacent steel sleeve sections exceeds a set threshold, measures are taken to make corrections.

[0015] Preferably, in step d, the following measures are taken for correction: grouting reinforcement is performed from the adjacent steel sleeve to the crushed stone buffer layer outside the adjacent steel sleeve.

[0016] Preferably, in step d, the following measures are taken for correction: first, part of the gravel in the gravel buffer layer outside the adjacent steel sleeves is released, and then the positions of the two sections of the steel sleeves are corrected to reduce the difference in displacement change.

[0017] The key technical means and beneficial effects of the present invention are:

[0018] 1. The present invention sets the starting point of tunnel construction on the low-inclination side and the exit on the high-inclination side. During tunnel construction, when the construction reaches a certain inclined rock layer, more gravity of the inclined rock layer is supported by the small hill on the high-inclination side where the tunnel is not constructed, thereby reducing tunnel deformation and facilitating later support.

[0019] 2. The present invention adopts a combined steel ring to support the excavated complete rock layer, wherein the inclined steel ring is arranged at an angle and its inclination direction is consistent with the inclination direction of the inclined rock layer, and completely covers the excavated complete rock layer. The combined positive steel ring is perpendicular to the axis of the tunnel, and the inclined steel ring and the combined positive steel ring are connected and fixed at the horizontal bisector of the tunnel; the inclined steel ring is mainly used to reduce the uneven displacement between the inclined rock layers. The combined positive steel ring can improve the strength and supporting capacity of the inclined steel ring on the one hand, and strengthen the support of the rock layer in the tunnel on the other hand.

[0020] 3. The construction of the pumped-storage water channel in this invention is divided into two layers: an inner and outer tunnel. First, a large-diameter tunnel is constructed. Within this tunnel, a tunnel for actual water flow, i.e., a deformation-resistant steel sleeve, is then installed. A gravel buffer layer is constructed between the two. This layer dilutes the uneven creep of the inclined rock formation and reduces the displacement differences between the steel sleeves. Later, corrective measures can be taken based on actual displacement monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the inclined cross section of the pumped storage power station tunnel of the present invention;

[0022] Figure 2 This is a schematic cross-sectional view of the tunnel of the pumped storage power station according to the present invention;

[0023] Figure 3 It is a schematic diagram of the inclined cross section of the water tunnel of the pumped storage power station of the present invention.

[0024] In the figure, 1-hill; 2-inclined rock layer; 21-rock layer surface; 3-starting point; 4-exit; 5-independent positive steel ring; 6-combined steel ring; 61-inclined steel ring; 62-combined positive steel ring; 7-connecting reinforcement; 8-tunnel; 91-steel sleeve; 92-axial reinforcement; 93-annular reinforcement; 10-anti-deformation steel sleeve; 11-gravel buffer layer; 12-corrugated pipe. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] like Figure 1As shown in the figure, there is a hillock 1 that the pumped-storage power station tunnel 8 of the present invention needs to pass through. The rock strata of the hillock 1 are inclined due to geological activities. When the tunnel 8 passes through the hillock 1 along the inclination, the adjacent inclined rock strata 2 may produce uneven creep displacement into the tunnel 8, causing the cross-sectional dimensions of the tunnel 8 to vary unevenly along the axial direction (i.e., the strike direction). The dislocation position is located at the rock layer 21 between the inclined rock strata 2. In response to this, the present invention proposes a method for safe construction and deformation monitoring of a pumped-storage power station tunnel passing through inclined rock strata to solve the above technical problems. The axial direction of the tunnel 8 of the pumped-storage power station is consistent with the inclination of the inclined rock strata 2. The pumped-storage power station tunnel is constructed along the inclination, including the following steps:

[0027] a. Figure 1 As shown, the starting port 3 of the tunnel 8 is set on the low-inclination side, and the exit 4 is set on the high-inclination side. In this way, when the tunnel 8 is constructed, when the construction reaches a certain inclined rock layer 2, more of the gravity of the inclined rock layer is supported by the hillock 1 on the high-inclination side where the tunnel 8 is not constructed.

[0028] b. Excavate a tunnel 8 from the starting port 3 toward the exit 4, and use an independent positive steel ring 5 for support at the starting port 3. The independent positive steel ring 5 is a circular steel ring with a certain width, and the independent positive steel ring 5 is perpendicular to the axis of the tunnel 2; after each complete excavation of a rock layer 21, a combined steel ring 6 is used to support the excavated complete rock layer 21. The combined steel ring 6 consists of an inclined steel ring 61 and a combined positive steel ring 62. The inclined steel ring 61 and the combined positive steel ring 62 are both circular steel rings with a certain width. The inclined steel ring 61 is tilted and its tilt direction The inclined direction is consistent with the inclined rock layer 2, and the complete rock layer layer 21 excavated is completely covered. The combined positive steel ring 62 is perpendicular to the axis of the tunnel 2. The inclined steel ring 61 and the combined positive steel ring 62 are connected and fixed at the horizontal bisector of the tunnel. Preferably, the inclined steel ring 61 and the combined positive steel ring 62 are integrally formed. When the construction reaches the exit 4, the independent positive steel ring 5 is used for support. The adjacent independent positive steel rings 5 ​​and the combined steel ring 6, and the combined steel ring 6 and the combined steel ring 6 are connected by connecting bars 7, and the tunnel excavation wall and the independent positive steel rings 5 ​​and the combined steel ring 6 are sprayed with concrete.

[0029] The complete excavation of a rock layer 21 means that the excavated tunnel completely exposes a rock layer; if the independent positive steel ring and the combination steel ring 5 and 6 overlap at the starting port 3 and the exit 4, the independent positive steel ring and the combination steel ring 5 and 6 can be fixedly connected together, such as Figure 1 Exit;

[0030] c. Figure 2-3As shown, part of the crushed stone is filled into the lower part of the tunnel 8, and then an anti-deformation steel sleeve 10 is laid on the upper part of the crushed stone, a water passage is formed inside the anti-deformation steel sleeve 10, the anti-deformation steel sleeve 10 includes a plurality of steel sleeve sections 91, adjacent steel sleeves 91 are connected by a bellows 12, and reinforcement ribs are welded on the outer wall of the steel sleeve 91, the reinforcement ribs include axial reinforcement ribs 92 and annular reinforcement ribs 93 that are crisscrossed; the axial center line of the anti-deformation steel sleeve 10 is parallel to the axial center line of the tunnel 8; crushed stone is filled between the tunnel 8 and the anti-deformation steel sleeve 10 to form a crushed stone buffer layer 11 together with the crushed stone that has been filled; the annular space between the tunnel 8 and the anti-deformation steel sleeve 10 is closed at the starting port 3 and the outlet 4, thereby closing the crushed stone buffer layer 11; preferably, the axial center line of the anti-deformation steel sleeve 10 is located directly below the axial center line of the tunnel 8, that is, the anti-deformation steel sleeve 10 is eccentrically arranged downward in the tunnel 8;

[0031] d. A displacement monitoring device is provided on each section of the steel sleeve 91 to monitor the displacement changes of each section of the steel sleeve 91; when the displacement change difference between two adjacent sections of the steel sleeve 91 exceeds a set threshold, corrective measures are taken; for example, grouting reinforcement is performed from the two sections of the steel sleeve 91 to the external gravel buffer layer 11 thereof, so that the external gravel buffer layer 11 of the two sections of the steel sleeve 91 is reinforced into a whole, thereby improving the ability to resist deformation; or, first, some gravel is released from the external gravel buffer layer 11 of the two sections of the steel sleeve 91, and then the position of the two sections of the steel sleeve 91 is corrected to reduce the displacement change difference.

[0032] 1. The present invention sets the starting port 3 for the construction of the tunnel 8 on the low-inclination side and the exit 4 on the high-inclination side. During the construction of the tunnel 8, when the construction reaches a certain inclined rock layer 2, more of the gravity of the inclined rock layer is supported by the hillock 1 on the high-inclination side where the tunnel 8 is not constructed, thereby reducing the deformation of the tunnel 8 and facilitating the later support.

[0033] 2. The present invention adopts a combined steel ring 6 to support the excavated complete rock layer 21, wherein the inclined steel ring 61 is inclined and its inclination direction is consistent with the inclination direction of the inclined rock layer 1, and completely covers the excavated complete rock layer 21, the combined positive steel ring 62 is perpendicular to the axis of the tunnel 2, and the inclined steel ring 61 and the combined positive steel ring 62 are connected and fixed at the horizontal bisector of the tunnel; the inclined steel ring 61 is mainly used to reduce the uneven displacement between the inclined rock layers 2, and the combined positive steel ring 62 can, on the one hand, improve the strength and supporting capacity of the inclined steel ring 61, and on the other hand, can strengthen the support of the rock layer in the tunnel.

[0034] 3. The construction of the water passage for pumped storage in this invention is divided into two layers: an inner and outer layer. First, a large-diameter tunnel 8 is constructed. Then, within it, a tunnel for actual water flow, namely, a deformation-resistant steel sleeve 10, is installed. A gravel buffer layer 11 is constructed between the two. Gravel buffer layer 11 can dilute the uneven creep of the inclined rock layer 2 and reduce the displacement difference between the steel sleeves 91. Later, corrective measures can be taken based on actual displacement monitoring.

[0035] Of course, the above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above-mentioned embodiments. It should be noted that all equivalent substitutions and obvious deformation forms made by any technician familiar with this field under the guidance of this specification fall within the substantive scope of this specification and should be protected by the present invention.

Claims

1. A method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations. The pumped storage power station tunnel is constructed along the inclination direction, which is characterized by: The steps include: a. The starting point of the tunnel construction should be set on the low-inclination side, and the exit should be set on the high-inclination side; b. Excavate the tunnel from the starting point toward the exit. After each complete excavation of a rock layer, use a combination of steel rings to support the excavated complete rock layer. The combination of steel rings includes an inclined steel ring and a combined positive steel ring. Both the inclined steel ring and the combined positive steel ring are circular steel rings with a certain width. The inclined steel ring is arranged at an angle, and its inclination direction is consistent with the inclination direction of the inclined rock layer, and completely covers the excavated complete rock layer. The combined positive steel ring is perpendicular to the axis of the tunnel. The inclined steel ring and the combined positive steel ring are connected and fixed at the horizontal bisector of the tunnel. c. Filling the lower portion of the tunnel with crushed stone, and then laying an anti-deformation steel sleeve on top of the crushed stone. The anti-deformation steel sleeve comprises several steel sleeve sections, with adjacent steel sleeves connected by bellows; the axial centerline of the anti-deformation steel sleeve is parallel to the axial centerline of the tunnel; filling the space between the tunnel and the anti-deformation steel sleeve with crushed stone to form a crushed stone buffer layer; sealing the annular space between the tunnel and the anti-deformation steel sleeve at the starting point and the exit, thereby sealing the crushed stone buffer layer; d. A displacement monitoring device is installed on each section of the steel sleeve to monitor the displacement changes of each section of the steel sleeve.

2. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 1 is characterized in that: In step b, the inclined steel ring and the combined straight steel ring are formed as one piece.

3. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 1 is characterized in that: In step b, independent positive steel rings are used for support at the starting point and the exit. The independent positive steel ring is a circular steel ring with a certain width, and the independent positive steel ring is perpendicular to the axis of the tunnel.

4. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 3 is characterized in that: In step b, connecting bars are used to connect adjacent independent positive steel rings and combined steel rings, and combined steel rings and combined steel rings, and concrete is sprayed to cover the tunnel excavation wall and the independent positive steel rings and combined steel rings.

5. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 3 is characterized in that: In step b, if the independent positive steel ring and the combined steel ring overlap at the starting port and the exit, the independent positive steel ring and the combined steel ring are fixedly connected together.

6. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 1, characterized in that: In step c, reinforcing ribs are welded to the outer wall of the steel sleeve, and the reinforcing ribs include axial reinforcing ribs and annular reinforcing ribs that are crisscrossed.

7. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 1, characterized in that: In step c, the anti-deformation steel sleeve is eccentrically arranged downward in the tunnel.

8. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 1, characterized in that: In step d, when the displacement change difference between two adjacent steel sleeve sections exceeds a set threshold, measures are taken to make corrections.

9. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 8, characterized in that: In step d, the following correction measures are taken: grouting reinforcement is performed from the adjacent steel sleeve to the crushed stone buffer layer outside it.

10. The method for safe construction and deformation monitoring of a pumped storage power station tunnel passing through inclined rock formations according to claim 8, characterized in that: In step d, the following measures are taken to make corrections: first, some gravel in the gravel buffer layer outside the adjacent steel sleeves is released, and then the positions of the two sections of steel sleeves are corrected to reduce the difference in displacement changes.

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