Hydraulic tunnel vertical shaft structure applied to soil rock stratum and construction method

Abstract

The invention discloses a hydraulic tunnel vertical shaft structure applied to a soil rock stratum and a construction method.The vertical shaft structure comprises a vertical shaft body, a plurality of row piles are arranged on the periphery of the vertical shaft body, a plurality of rock stress testing drill holes are formed in the periphery of the row piles, and rock stress sensors with different depths are arranged in the rock stress testing drill holes; the rock stress sensor is connected with the controller through a signal line, a bottom plate is arranged at the bottom of the vertical shaft body, and a reinforced concrete wall is arranged on the bottom plate and extends to a soil layer. A plurality of waist beams for supporting the row piles are sequentially arranged on the soil layer in the depth direction. A combined structure system of the upper-section row piles and the lower-section underground reinforced concrete wall is innovatively adopted, combined stress is achieved through rigid connection of combined parts, and the combined structure is precisely matched with the stratum characteristics of the upper covering soil layer and the lower I / II / III type stable surrounding rock.

Description

Technical Field

[0001] This invention relates to the structure and construction method of vertical shafts for hydraulic tunnels in soil and rock strata, belonging to the field of water conservancy engineering technology. Background Technology

[0002] For water conservancy projects in karst areas, the vertical shafts for water intake tunnels, pumping stations, and surge chambers; the launching and receiving shafts for shield tunnels; and the working and receiving shafts for pipe jacking tunnels are often ultra-deep. The geology typically consists of a soil layer from the surface down, ranging from several meters to tens of meters in thickness, or even deeper. Below this soil layer is usually a rock layer, with complex geological conditions, varying rock types, and abundant groundwater. The deeper the shaft, the greater the external water pressure and lateral rock pressure. Supporting ultra-deep shafts in such soil and rock strata presents a significant challenge. Current technology uses underground reinforced concrete walls for support, but this involves simultaneous excavation and support. The soil layer and poor surrounding rock conditions are prone to collapse, sometimes even before support can be applied, posing a high construction safety risk. Pile support is also problematic for ultra-deep shafts tens or even hundreds of meters deep. Single-row piles have low stiffness and insufficient bearing capacity, while double-row piles are expensive. Therefore, there is an urgent need for a vertical shaft structure and construction method for water conservancy projects to solve the above-mentioned technical problems. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a vertical shaft structure and construction method for hydraulic tunnels in soil and rock strata, solving the technical problems of support structure and construction of ultra-deep vertical shafts with overlying soil layers above and rock strata below.

[0004] Technical Solution: To solve the above-mentioned technical problems, the present invention provides a construction method for a vertical shaft structure of a hydraulic tunnel applied in soil and rock strata, comprising the following steps: (1) GPS and total station were used to lay out the center coordinates of the shaft, the location of the piles and the location of the monitoring holes, and control piles were set up and protected; the pile positions were marked according to the pile spacing, and the thickness of the overburden layer and the distribution of the rock layer were checked in the survey report; (2) Move the rotary drilling rig to the pile position, adjust the machine body to be level, align the center of the drill bit with the pile position mark, install the casing, and drill to the designed depth according to the principle of "drilling from shallow to deep and in stages". Use a borehole measuring instrument to check the hole diameter; use the mud circulation method to clean the hole and remove rock powder and sediment from the bottom of the hole. (3) The steel bars shall be fabricated in the steel bar processing yard according to the design drawings, with the main bar spacing deviation ≤10mm and the stirrup spacing deviation ≤20mm; (4) Steel pipes are used, and concrete is injected into the pipes through a concrete pump for continuous pouring. The initial pouring volume ensures that the pipes are buried in the concrete for ≥1.2m. During subsequent pouring, the burial depth of the pipes is controlled at 2-6m. The pipes are gradually raised as the pouring progresses to complete the pile foundation pouring and the concrete is cured. (5) After the concrete strength of the pile reaches 70% of the design strength, remove the laitance and excess concrete at the top of the pile to expose the fresh concrete surface and clean the reinforcing steel at the pile head. (6) Mark out the axis and elevation control line of the cap beam, use steel and wood formwork, apply release agent to the inside of the formwork, weld the cap beam reinforcement to the reserved reinforcement of the pile, set the stirrup densification zone according to the design, use C35 concrete, pour and compact in layers, and cover and cure in time after pouring. (7) At 1.5m on the outer wall of the pile, mark the location of the monitoring holes according to the design spacing, symmetrically distributed with the pile. Drill the holes with a drilling rig, with a diameter of 200-500mm and a depth to the design elevation of the bottom plate of the shaft. Record the distribution of rock strata during the drilling process and compare and correct it with the exploration report. (8) Sensor binding: Bind the multi-point rock stress gauge of one hole to the outer wall of the grouting pipe according to the design spacing. Mark the sensor cable with numbers. Slowly insert the grouting pipe with the bound sensor into the bottom of the hole. Use a grouting pump to grout the pipe opening at low pressure. The grout overflows from the plum blossom-shaped grout outlet of the pipe wall and gradually fills the gap in the hole. Observe the hole opening during the grouting process. When pure grout overflows from the hole opening and there are no air bubbles, continue grouting for 3-5 minutes. (9) After grouting is completed, the hole is sealed and the grout is naturally cured for 72 hours. After the grout strength reaches 70% of the design strength, the sensor is started to collect initial data and record the original stress and displacement reference values. (10) Layered excavation shall be adopted, with each layer having an excavation depth of ≤2m. When the depth reaches the first wainscoting construction, the well wall soil and rock at the wainscoting installation location shall be cleaned, and the reinforcing bars shall be tied according to the wainscoting design drawings. The wainscoting reinforcing bars shall be welded to the reserved reinforcing bars of the pile, with a welding length of ≥10d. Steel and wood formwork shall be used, and the formwork support shall be made of tie bolts + steel pipe scaffolding. The formwork joints shall be tight, and C35 concrete shall be used. The concrete shall be poured in layers and vibrated to compact it. After the pouring is completed, it shall be covered and cured for no less than 7 days. (11) Following the above process, continue excavating layer by layer to the design elevation of the next wainscoting, and construct the second, third and so on until the last wainscoting is completed; the spacing between wainscotings is according to the design value, and rock stress and displacement data are read in real time during the excavation process; (12) Excavation to below the overburden layer: Continue excavation in layers until the excavation reaches 1.0m below the interface between the overburden layer and the rock layer. Construct according to the design drawings of the interlocking beam. Use steel and wood formwork. The formwork support uses tie bolts + steel pipe scaffolding. The formwork joints are tight. Use C35 concrete. Pour in layers and vibrate to compact. After pouring, cover and cure for no less than 7 days. (13) Excavate the lower rock layer, carry out well wall anchor bolt and steel mesh spray anchor construction until the preset depth is reached, and set the bottom plate at the bottom; (14) Construction of the first layer of wall from the bottom plate upwards. Tie the well wall reinforcement according to the wall design drawings. Use standard steel formwork. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, check the axis, elevation and verticality. Use C40 impermeable concrete. Pour the concrete in layers through the concrete pump. Cover and moisturize the concrete within 12 hours after the concrete is poured. Remove the formwork after the concrete strength reaches 70% of the design strength. (15) Construct the second, third and so on reinforced concrete walls in sequence. Before constructing each section of the wall, clean the concrete bonding surface of the previous section of the wall until the entire structure is completed.

[0005] As a preferred option, in step (7), when the surrounding rock category is Class I, Class II, or Class III, the borehole design depth is taken as the depth of the overburden layer plus the shaft diameter, and the shaft diameter is the maximum distance between two points on the cross-section of the shaft. Preferably, in step (7), when the surrounding rock category is Class IV or Class V, the borehole design depth is taken as the shaft design depth plus the shaft diameter, and the shaft diameter is the maximum distance between two points on the shaft cross-section.

[0006] Preferably, step (13) specifically involves: (131) Excavate the lower rock layer to a depth of one unit, keeping the well wall flat during the excavation process; (132) Drill holes using a pneumatic rock drill at the designed spacing, with the hole depth as designed, and slowly insert the anchor rod into the hole, with the exposed length of the anchor rod ≥ 500 mm; (133) M30 cement grout was used to inject grout into the hole through the grouting pipe. After the grouting was full, the hole was sealed and cured for 7 days. (134) Steel mesh processing: φ6-φ8 steel bars are used and processed into steel mesh according to the design spacing. The overlap length of the mesh is ≥200mm. The mesh is tied and laid tightly against the well wall and welded to the exposed end of the anchor rod. The protective layer thickness of the mesh is ≥50mm. The mesh is laid flat and without loosening or sagging. (135) Concrete preparation: C25 shotcrete is used, and a wet shotcrete machine is used for spraying. The spraying sequence is from bottom to top, and the layers are sprayed. The vibration function of the shotcrete machine is used to ensure that the concrete is dense. Water curing is carried out within 12 hours after spraying, and the curing time is not less than 7 days. (136) Collect rock stress gauge data synchronously and compare it with preset data. If the stress value exceeds 10%, add two rows of anchor rods to the next layer. If the stress value is less than 80%, reduce one row of anchor rods to the next layer. (137) After each layer is excavated, the axis and diameter of the well wall are checked with a total station. The deviation is controlled within ±50mm. Repeat steps (131)-(137).

[0007] Preferably, step (14) consists of the following steps: (141) Read the rock stress gauge data in real time and compare it with the preset data. If the stress value exceeds the preset value by 10%, increase the concrete strength grade; if the stress value is within the preset range, construct according to the original design. (142) Construction of the first layer of wall from the bottom slab upwards. The wall reinforcement is tied according to the wall design drawings. Standard steel formwork is used. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, the axis, elevation and verticality are checked. C40 impermeable concrete is used. It is poured in layers by concrete pump. The concrete is covered and moisturized within 12 hours after the concrete is poured. The formwork is removed after the concrete strength reaches 70% of the design strength.

[0008] Preferably, in step (142) or step (15), rock-embedded anti-buoyancy components are installed on the shaft wall, with a circumferential net spacing of 3 meters. The rock-embedded anti-buoyancy components are wedge-shaped reinforced concrete structures, embedded in the rock layer to a depth ≥1.5m, with a cross-sectional dimension of 500×800mm. The rock-embedded anti-buoyancy components are integrally cast with the reinforced concrete wall of the shaft, with a circumferential net spacing of 3 meters and a longitudinal spacing according to the design value.

[0009] Preferably, step (13) specifically involves: (131) Excavate the lower rock layer to a depth of one unit, keeping the well wall flat during the excavation process; (132) Drill holes using a pneumatic rock drill at the designed spacing, with the hole depth as designed, and slowly insert the anchor rod into the hole, with the exposed length of the anchor rod ≥ 500 mm; (133) M30 cement grout was used to inject grout into the hole through the grouting pipe. After the grouting was full, the hole was sealed and cured for 7 days. (134) Steel mesh processing: φ6-φ8 steel bars are used and processed into steel mesh according to the design spacing. The overlap length of the mesh is ≥200mm. The mesh is tied and laid tightly against the well wall and welded to the exposed end of the anchor rod. The protective layer thickness of the mesh is ≥50mm. The mesh is laid flat and without loosening or sagging. (135) Concrete preparation: C25 shotcrete is used, and a wet shotcrete machine is used for spraying. The spraying sequence is from bottom to top, and the layers are sprayed. The vibration function of the shotcrete machine is used to ensure that the concrete is dense. Water curing is carried out within 12 hours after spraying, and the curing time is not less than 7 days. (136) Collect rock stress gauge data synchronously and compare it with preset data. If the stress value exceeds 5%, add two rows of anchor rods to the next layer. If the stress value is less than 80%, reduce one row of anchor rods to the next layer. (137) After each layer is excavated, the axis and diameter of the well wall are checked with a total station. The deviation is controlled within ±50mm. Repeat steps (131)-(137).

[0010] Preferably, step (14) consists of the following steps: (141) If the stress value exceeds the preset value by 5%, the concrete strength grade shall be increased; if the stress value is within the preset range, construction shall be carried out according to the original design. (142) Construction of the first layer of wall from the bottom slab upwards. The wall reinforcement is tied according to the wall design drawings. Standard steel formwork is used. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, the axis, elevation and verticality are checked. C40 impermeable concrete is used. It is poured in layers by concrete pump. The concrete is covered and moisturized within 12 hours after the concrete is poured. The formwork is removed after the concrete strength reaches 70% of the design strength.

[0011] Preferably, in step (14) or (15), the piles and the underground reinforced concrete wall are welded together with reinforcing bars.

[0012] A vertical shaft structure for hydraulic tunnels in soil and rock strata includes a shaft body, a plurality of piles surrounding the shaft body, and a plurality of rock stress testing boreholes surrounding the piles. Rock stress sensors at different depths are installed in the rock stress testing boreholes, and the rock stress sensors are connected to a controller via signal lines. The piles pass through soil, Class IV and Class V surrounding rock strata in sequence. A base plate is installed at the bottom of the shaft body, and a reinforced concrete wall is installed on the base plate, extending to the upper soil layer. A plurality of waist beams supporting the piles are installed in sequence along the depth direction in the soil layer. The reinforced concrete wall is anchored to the Class I, Class II and Class III surrounding rock strata by rock-embedded anti-buoyancy components.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following advantages: 1. Pile-wall type shaft: Adapted to soil and rock strata in a layered manner, it innovatively adopts a combined structural system of "upper section piles + lower section underground reinforced concrete wall". Through rigid connection at the joint, it achieves joint stress and is precisely adapted to the strata characteristics of "upper overburden soil layer + lower Class I / II / III stable surrounding rock". The upper overburden soil layer has complex geological conditions and poor stability. Reliable lateral support is formed first through piles, which ensures the safety of construction personnel and machinery during shaft excavation from the root. The lower Class I / II / III surrounding rock has good integrity and strong self-stabilizing ability. The construction logic of "excavating to the bottom of the shaft first, and then pouring the underground reinforced concrete wall as a whole" is adopted. There is no need for temporary support at the same time, which greatly reduces the time of cross-operation. While ensuring the support effect, it significantly saves construction time and project investment.

[0014] 2. Rock-embedded anti-buoyancy components: The underground reinforced concrete wall is equipped with protruding rock-embedded anti-buoyancy components. Through a structural design that is embedded within the rock, these components leverage their high rigidity and strong anti-buoyancy bearing capacity. This forms a triple anti-buoyancy system: the shear force of the protruding rock-embedded components + the pull-out force of the upper piles + the overall weight of the shaft structure. This system works synergistically to resist groundwater buoyancy, resulting in superior anti-buoyancy stability. Compared to conventional anchor bolt anti-buoyancy solutions, this rock-embedded anti-buoyancy component does not rely on long-term contact between the anchor bolt and groundwater, fundamentally avoiding the problems of anchor bolt corrosion and aging failure under groundwater erosion. This achieves long-term stable anti-buoyancy performance and meets the stringent requirements of long-term underwater service in hydraulic engineering projects.

[0015] 3. Real-time monitoring of rock stress: During the shaft excavation process, the deformation caused by rock unloading is captured in real time by stress gauges embedded in the rock strata. Surrounding rock stress and displacement data are simultaneously collected and fed back to the design end, accurately verifying the rationality of the rock lateral pressure load adopted in the initial design. If a deviation is found between the design load and the actual working conditions, it can be dynamically corrected by increasing the thickness of the underground reinforced concrete wall, optimizing the reinforcement amount, or increasing the concrete strength grade, ensuring that the shaft structure's bearing capacity accurately matches the actual stress. Conversely, design parameters can be optimized to avoid waste caused by excessive reinforcement. This truly realizes full-process control of underground structures from "data acquisition - dynamic design - dynamic construction," ensuring the long-term safety and stability of the shaft structure from a technical perspective, while improving the accuracy of design and construction.

[0016] 4. Full-Section Pile Adaptation Solution: Specifically designed to solve the challenges of supporting ultra-deep fractured rock, this solution addresses the complex strata of an overlying soil layer and underlying Class IV / V fractured rock. The piles extend below the bottom of the shaft, forming an integrated structure with the lower underground reinforced concrete wall. The continuously arranged piles provide full-area lateral support to the overlying soil layer and fractured rock, effectively constraining the large deformation and collapse risks of Class IV / V rock, providing comprehensive safety assurance for shaft excavation operations. This also avoids interference between temporary support and excavation, significantly shortening the construction period. After the shaft is excavated to the bottom, the poured underground reinforced concrete wall tightly integrates with the full-section piles, forming a high-strength, high-rigidity composite support system. This not only meets the stringent requirements of ultra-deep shafts for ultimate bearing capacity, deformation control, and safety stability but also successfully overcomes the technical challenges of supporting ultra-deep shafts in such adverse strata. Attached Figure Description

[0017] Figure 1 This is a plan view of the vertical shaft structure of the crown beam layer of the present invention.

[0018] Figure 2 This is a plan view of the vertical shaft structure of the waist beam layer of the present invention.

[0019] Figure 3 This is a schematic diagram of the vertical shaft in Example 1.

[0020] Figure 4 This is a three-dimensional schematic diagram of the vertical shaft in Example 1.

[0021] Figure 5 This is a schematic diagram of the vertical shaft in Example 2.

[0022] Figure 6 This is a detailed drawing of the connection between the wainscoting and the pile.

[0023] In the diagram: 11. Support beam; 12. Monitoring hole; 13. Pile top cap beam; 14. Pile piles; 15. Grouting pipe; 16. Waist beam; 17. Pile top cap beam; 18. Locking beam; 19. Rebar sleeve; 20. Underground reinforced concrete wall; 21. Anchor bolt; 22. Shotcrete; 23. Base plate; 24. Rock-embedded anti-buoyancy component; 25. Waist beam longitudinal reinforcement; 26. Waist beam stirrups; 27. Waist beam. Detailed Implementation

[0024] The invention will now be further described with reference to the accompanying drawings. Example

[0025] According to the survey report, the rock strata in this embodiment are classified as Class I, Class II, and Class III rock strata.

[0026] A construction method for a vertical shaft structure of a hydraulic tunnel applied in soil and rock strata includes the following steps: (1) GPS and total station were used to lay out the center coordinates of the shaft, the location of the piles and the location of the monitoring holes, and control piles were set up and protected; the pile positions were marked according to the pile spacing, and the thickness of the overburden layer and the distribution of the rock layer were checked in the survey report; (2) Move the rotary drilling rig to the pile position, adjust the machine body to be level, align the center of the drill bit with the pile position mark, install the casing, and drill to the designed depth according to the principle of "drilling from shallow to deep and in stages". After drilling to the designed depth, use a borehole measuring instrument to check the hole diameter. The designed drilling depth is the depth of the overburden layer plus the diameter of the shaft. The diameter of the shaft is the maximum distance between two points on the cross-section of the shaft. Use the mud circulation method to clean the hole and remove rock powder and sediment from the bottom of the hole. (3) Fabricate steel bars according to the design drawings at the steel bar processing yard; (4) Steel pipes are used, and concrete is injected into the pipes by a concrete pump for continuous pouring. During subsequent pouring, the burial depth of the pipes is controlled at 2-6m. The pipes are gradually raised as the pouring progresses to complete the pile pouring and the concrete is cured. (5) After the concrete strength of the pile reaches 70% of the design strength, remove the laitance and excess concrete at the top of the pile to expose the fresh concrete surface and clean the reinforcing steel at the pile head. (6) Mark out the axis and elevation control line of the cap beam, use steel and wood formwork, apply release agent to the inside of the formwork, weld the cap beam reinforcement to the reserved reinforcement of the pile, set the stirrup densification zone according to the design, use C35 concrete, pour and compact in layers, and cover and cure in time after pouring. (7) At 1.5m on the outer wall of the pile, mark the location of the monitoring holes according to the design spacing, symmetrically distributed with the pile. Drill the holes with a drilling rig, with a diameter of 200-500mm and a depth to the design elevation of the bottom plate of the shaft. Record the distribution of rock strata during the drilling process and compare and correct it with the exploration report. (8) Sensor binding: Bind the multi-point rock stress gauge of one hole to the outer wall of the grouting pipe according to the design spacing. Mark the sensor cable with numbers. Slowly insert the grouting pipe with the bound sensor into the bottom of the hole. Use a grouting pump to grout the pipe opening at low pressure. The grout overflows from the plum blossom-shaped grout outlet of the pipe wall and gradually fills the gap in the hole. Observe the hole opening during the grouting process. When pure grout overflows from the hole opening and there are no air bubbles, continue grouting for 3-5 minutes. (9) After grouting is completed, the hole is sealed and the grout is naturally cured for 72 hours. After the grout strength reaches 70% of the design strength, the sensor is started to collect initial data and record the original stress and displacement reference values. (10) Layered excavation shall be adopted, with each layer having an excavation depth of ≤2m. When the depth reaches the first wainscoting construction, the well wall soil and rock at the wainscoting installation location shall be cleaned, and the reinforcing bars shall be tied according to the wainscoting design drawings. The wainscoting reinforcing bars shall be welded to the reserved reinforcing bars of the piles. Steel and wood formwork shall be used, with tight formwork joints. C35 concrete shall be used, and it shall be poured and vibrated to compact it in layers. After pouring, it shall be covered and cured for no less than 7 days. (11) Following the above process, continue excavating layer by layer to the design elevation of the next wainscoting, and construct the second, third and so on until the last wainscoting is completed; the spacing between wainscotings is according to the design value, and rock stress and displacement data are read in real time during the excavation process; (12) Excavation to below the overburden layer: Continue excavation in layers until the excavation reaches 1.0m below the interface between the overburden layer and the rock layer. Construct according to the design drawings of the interlocking beam. Use steel and wood formwork. The formwork support uses tie bolts + steel pipe scaffolding. The formwork joints are tight. Use C35 concrete. Pour in layers and vibrate to compact. After pouring, cover and cure for no less than 7 days. (13) Excavate the lower rock layer, carry out well wall anchor bolt and steel mesh spray anchor construction until the preset depth is reached, and set the bottom plate at the bottom; The specific steps (13) are as follows: (131) Excavate the lower rock layer to a depth of one unit, keeping the well wall flat during the excavation process; (132) Drill holes using a pneumatic rock drill at the designed spacing, with the hole depth as designed, and slowly insert the anchor rod into the hole, with the exposed length of the anchor rod ≥ 500 mm; (133) M30 cement grout was used to inject grout into the hole through the grouting pipe. After the grouting was full, the hole was sealed and cured for 7 days. (134) Steel mesh processing: φ6-φ8 steel bars are used and processed into steel mesh according to the design spacing. The overlap length of the mesh is ≥200mm. The mesh is tied and laid tightly against the well wall and welded to the exposed end of the anchor rod. The protective layer thickness of the mesh is ≥50mm. The mesh is laid flat and without loosening or sagging. (135) Concrete preparation: C25 shotcrete is used, and a wet shotcrete machine is used for spraying. The spraying sequence is from bottom to top, and the layers are sprayed. The vibration function of the shotcrete machine is used to ensure that the concrete is dense. Water curing is carried out within 12 hours after spraying, and the curing time is not less than 7 days.

[0027] (136) Collect rock stress gauge data synchronously and compare it with the preset data. If the stress value exceeds 10%, add two rows of anchor rods to the next layer. If the stress value is less than 80%, reduce one row of anchor rods in the next layer. Otherwise, process the anchor rods according to the number of rows in the previous layer. (137) After each layer is excavated, the axis and diameter of the well wall are checked with a total station. The deviation is controlled within ±50mm. Repeat steps (131)-(137).

[0028] (14) Construction of the first layer of wall from the bottom plate upwards. Tie the well wall reinforcement according to the wall design drawings. Use standard steel formwork. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, check the axis, elevation and verticality. Use C40 impermeable concrete. Pour the concrete in layers through the concrete pump. Cover and moisturize the concrete within 12 hours after the concrete is poured. Remove the formwork after the concrete strength reaches 70% of the design strength. (141) Read the rock stress gauge data in real time and compare it with the preset data. If the stress value exceeds the preset value by 10%, the concrete strength grade shall be increased when constructing the next layer; if the stress value is within the preset range, construction shall be carried out according to the original design. (142) Construction of the first wall layer from the bottom slab upwards. In the construction of each wall layer, rock-embedded anti-buoyancy components are set up. The well wall reinforcement is tied according to the wall design drawings. Standard steel formwork is used. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, the axis, elevation and verticality are checked. C40 impermeable concrete is used. It is poured in layers by concrete pump. After the concrete is poured, it is covered and moisturized for 12 hours. After the concrete strength reaches 70% of the design strength, the formwork is removed. The rock-embedded anti-buoyancy component is a wedge-shaped reinforced concrete structure. The depth of embedding into the rock layer is ≥1.5m. The cross-sectional size is 500×800mm. HRB400 grade φ25mm main reinforcement and φ8mm stirrups are used. The rock-embedded anti-buoyancy component is integrally poured with the well wall reinforced concrete wall. The circumferential net spacing is 3 meters. The longitudinal spacing is as designed. (15) Construct the second, third and so on reinforced concrete walls in sequence. Before constructing each section of the wall, clean the concrete bonding surface of the previous section of the wall until the entire structure is completed.

[0029] Using the above process, the constructed shaft structure is as follows: Figure 1 , 2 As shown in Figures 3 and 4, a vertical shaft structure for hydraulic tunnels applied in soil and rock strata includes a shaft body, a plurality of piles surrounding the shaft body, a plurality of rock stress testing boreholes surrounding the piles, rock stress sensors at different depths installed in the rock stress testing boreholes, the rock stress sensors being connected to a controller via signal lines, the piles sequentially penetrating the soil layers, a base plate being installed at the bottom of the shaft body, a reinforced concrete wall being installed on the base plate extending into the soil layers, a plurality of waist beams and support beams being sequentially installed along the depth direction in the soil layers, and a plurality of support beams being installed along the depth direction of the reinforced concrete wall, the reinforced concrete wall being anchored to Class I, Class II and Class III surrounding rock strata by rock-embedded anti-buoyancy components. Example

[0030] According to the survey report, the rock strata in this embodiment are Class IV and Class V surrounding rocks.

[0031] A construction method for a vertical shaft structure of a hydraulic tunnel applied in soil and rock strata includes the following steps: (1) GPS and total station were used to lay out the center coordinates of the shaft, the location of the piles and the location of the monitoring holes, and control piles were set up and protected; the pile positions were marked according to the pile spacing, and the thickness of the overburden layer and the distribution of the rock layer were checked in the survey report; (2) Move the rotary drilling rig to the pile position, adjust the machine body to be level, align the center of the drill bit with the pile position mark, install the casing, and drill to the designed depth according to the principle of "drilling from shallow to deep and in stages". Use a borehole measuring instrument to check the hole diameter; use the mud circulation method to clean the hole and remove rock powder and sediment from the bottom of the hole. (3) Fabricate according to the design drawings at the steel bar processing plant; (4) Steel pipes are used, and concrete is injected into the pipes by a concrete pump for continuous pouring. During subsequent pouring, the burial depth of the pipes is controlled at 2-6m. The pipes are gradually raised as the pouring progresses to complete the pile pouring and the concrete is cured. (5) After the concrete strength of the pile reaches 70% of the design strength, remove the laitance and excess concrete at the top of the pile to expose the fresh concrete surface and clean the reinforcing steel at the pile head. (6) Mark out the axis and elevation control line of the cap beam, use steel and wood formwork, apply release agent to the inside of the formwork, weld the cap beam reinforcement to the reserved reinforcement of the pile, set the stirrup densification zone according to the design, use C35 concrete, pour and compact in layers, and cover and cure in time after pouring. (7) At 1.5m on the outer wall of the pile, mark the location of the monitoring holes according to the design spacing, symmetrically distributed with the pile. Drill the holes with a drilling rig, with a diameter of 200-500mm and a depth to the design elevation of the bottom plate of the shaft. Record the distribution of rock strata during the drilling process and compare and correct it with the exploration report. (8) Sensor binding: Bind the multi-point rock stress gauge of one hole to the outer wall of the grouting pipe according to the design spacing. Mark the sensor cable with numbers. Slowly insert the grouting pipe with the bound sensor into the bottom of the hole. Use a grouting pump to grout the pipe opening at low pressure. The grout overflows from the plum blossom-shaped grout outlet of the pipe wall and gradually fills the gap in the hole. Observe the hole opening during the grouting process. When pure grout overflows from the hole opening and there are no air bubbles, continue grouting for 3-5 minutes. (9) After grouting is completed, the hole is sealed and the grout is naturally cured for 72 hours. After the grout strength reaches 70% of the design strength, the sensor is started to collect initial data and record the original stress and displacement reference values. (10) Layered excavation shall be adopted, with each layer having an excavation depth of ≤2m. When the depth reaches the first wainscoting construction, the well wall soil and rock at the wainscoting installation location shall be cleaned, and the reinforcing bars shall be tied according to the wainscoting design drawings. The wainscoting reinforcing bars shall be welded to the reserved reinforcing bars of the piles. Steel and wood formwork shall be used, with tight formwork joints. C35 concrete shall be used, and it shall be poured and vibrated to compact it in layers. After pouring, it shall be covered and cured for no less than 7 days. (11) Following the above process, continue excavating layer by layer to the design elevation of the next wainscoting, and construct the second, third and so on until the last wainscoting is completed; the spacing between wainscotings is according to the design value, and rock stress and displacement data are read in real time during the excavation process; (12) Excavation to below the overburden layer: Continue excavation in layers until the excavation reaches 1.0m below the interface between the overburden layer and the rock layer. Construct according to the design drawings of the interlocking beam. Use steel and wood formwork. The formwork support uses tie bolts + steel pipe scaffolding. The formwork joints are tight. Use C35 concrete. Pour in layers and vibrate to compact. After pouring, cover and cure for no less than 7 days. (13) Excavate the lower rock layer, carry out well wall anchor bolt and steel mesh spray anchor construction until the preset depth is reached, and set the bottom plate at the bottom; The specific steps (13) are as follows: (131) Excavate the lower rock layer to a depth of one unit, keeping the well wall flat during the excavation process; (132) Drill holes using a pneumatic rock drill at the designed spacing, with the hole depth as designed, and slowly insert the anchor rod into the hole, with the exposed length of the anchor rod ≥ 500 mm; (133) M30 cement grout was used to inject grout into the hole through the grouting pipe. After the grouting was full, the hole was sealed and cured for 7 days. (134) Steel mesh processing: φ6-φ8 steel bars are used and processed into steel mesh according to the design spacing. The overlap length of the mesh is ≥200mm. The mesh is tied and laid tightly against the well wall and welded to the exposed end of the anchor rod. The protective layer thickness of the mesh is ≥50mm. The mesh is laid flat and without loosening or sagging. (135) Concrete preparation: C25 shotcrete is used, and a wet shotcrete machine is used for spraying. The spraying sequence is from bottom to top, and the layers are sprayed. The vibration function of the shotcrete machine is used to ensure that the concrete is dense. Water curing is carried out within 12 hours after spraying, and the curing time is not less than 7 days.

[0032] (136) Collect rock stress gauge data synchronously and compare it with preset data. If the stress value exceeds 5%, add two rows of anchor rods to the next layer. If the stress value is less than 80%, reduce one row of anchor rods to the next layer. (137) After each layer is excavated, the axis and diameter of the well wall are checked with a total station. The deviation is controlled within ±50mm. Repeat steps (131)-(137).

[0033] (14) Construction of the first layer of wall from the bottom plate upwards. Tie the well wall reinforcement according to the wall design drawings. Use standard steel formwork. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, check the axis, elevation and verticality. Use C40 impermeable concrete. Pour the concrete in layers through the concrete pump. Cover and moisturize the concrete within 12 hours after the concrete is poured. Remove the formwork after the concrete strength reaches 70% of the design strength. The specific steps of step (14) are as follows: (141) If the stress value exceeds the preset value by 5%, the concrete strength grade shall be increased when constructing the next layer; if the stress value is within the preset range, construction shall be carried out according to the original design. (142) Construction of the first layer of wall from the bottom slab upwards. The piles and underground reinforced concrete walls are connected by welding. The well wall reinforcement is tied according to the wall design drawings. Standard steel formwork is used. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, the axis, elevation and verticality are checked. C40 impermeable concrete is used. It is poured in layers by concrete pump. The concrete is covered and moisturized within 12 hours after the concrete is poured. The formwork is removed after the concrete strength reaches 70% of the design strength.

[0034] (15) Construct the second, third and so on reinforced concrete walls in sequence. Before constructing each section of the wall, clean the concrete bonding surface of the previous section of the wall until the entire structure is completed.

[0035] Using the above process, the constructed shaft structure is as follows: Figure 1 , 2As shown in Figures 5 and 6, a vertical shaft structure for hydraulic tunnels applied in soil and rock strata includes a shaft body, a plurality of piles arranged around the shaft body, a plurality of rock stress testing boreholes arranged around the piles, rock stress sensors at different depths arranged in the rock stress testing boreholes, the rock stress sensors being connected to a controller via signal lines, the piles sequentially passing through soil and rock layers and extending to a bottom plate, a bottom plate being provided at the bottom of the shaft body, a reinforced concrete wall being provided on the bottom plate and extending to the upper soil layer; a plurality of waist beams and support beams supporting the piles are sequentially arranged along the depth direction in the soil layer, and a plurality of support beams are arranged along the depth direction of the reinforced concrete wall.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A construction method for a vertical shaft structure of a hydraulic tunnel applied in soil and rock strata, characterized in that, Includes the following steps: (1) GPS and total station were used to lay out the center coordinates of the shaft, the location of the piles and the location of the monitoring holes, and control piles were set up and protected; the pile positions were marked according to the pile spacing, and the thickness of the overburden layer and the distribution of the rock layer were checked in the survey report; (2) Move the rotary drilling rig to the pile position, adjust the machine body to be level, align the center of the drill bit with the pile position mark, install the casing, and drill to the designed depth according to the principle of "drilling from shallow to deep and in stages". Use a borehole measuring instrument to check the hole diameter; use the mud circulation method to clean the hole and remove rock powder and sediment from the bottom of the hole. (3) Fabricate according to the design drawings at the steel bar processing plant; (4) Steel pipes are used, and concrete is injected into the pipes by a concrete pump for continuous pouring. During subsequent pouring, the burial depth of the pipes is controlled at 2-6m. The pipes are gradually raised as the pouring progresses to complete the pile pouring and the concrete is cured. (5) After the concrete strength of the pile reaches 70% of the design strength, remove the laitance and excess concrete at the top of the pile to expose the fresh concrete surface and clean the reinforcing steel at the pile head. (6) Mark out the axis and elevation control line of the cap beam, use templates, apply release agent to the inside of the templates, weld the cap beam reinforcement to the reserved reinforcement of the pile, set the stirrup densification zone according to the design, pour and compact in layers, and cover and cure in time after pouring; (7) At 1.5m on the outer wall of the pile, mark the location of the monitoring holes according to the design spacing, symmetrically distributed with the pile. Drill the holes with a drilling rig, with a diameter of 200-500mm and a depth to the design elevation of the bottom plate of the shaft. Record the distribution of rock strata during the drilling process and compare and correct it with the exploration report. (8) Sensor binding: Bind the multi-point rock stress gauge of one hole to the outer wall of the grouting pipe at the designed spacing. Mark the sensor cable with numbers. Slowly insert the grouting pipe with the bound sensor into the bottom of the monitoring hole. Use a grouting pump to grout the pipe opening at low pressure. The grout overflows from the plum blossom-shaped grout outlet of the pipe wall and gradually fills the gap in the hole. Observe the hole opening during the grouting process. When pure grout overflows from the hole opening and there are no air bubbles, continue grouting for 3-5 minutes. (9) After grouting is completed, the hole is sealed and the grout is naturally cured for 72 hours. After the grout strength reaches 70% of the design strength, the sensor is started to collect initial data and record the original stress and displacement reference values ​​as preset data. (10) Layered excavation shall be adopted, with each layer having an excavation depth of ≤2m. When the depth reaches the first wainscoting construction, the well wall soil and rock at the wainscoting installation location shall be cleaned, and the reinforcing bars shall be tied according to the wainscoting design drawings. The wainscoting reinforcing bars shall be welded to the pre-reserved reinforcing bars of the piles. Steel and wood formwork shall be used, with tight formwork joints. The concrete shall be poured in layers and vibrated to compact it. After the pouring is completed, it shall be covered and cured for no less than 7 days. (11) Following the above process, continue excavating layer by layer to the design elevation of the next wainscoting, and construct the second, third and so on until the last wainscoting is completed; the spacing between wainscotings is according to the design value, and rock stress and displacement data are read in real time during the excavation process; (12) Excavate to below the overburden layer: Continue to excavate in layers until the excavation reaches 1.0m below the interface between the overburden layer and the rock layer. Construct according to the design drawings of the interlocking beam. Use steel and wood formwork. The formwork support uses tie bolts + steel pipe scaffolding. The formwork joints are tight. The concrete is poured in layers and vibrated to compact. After pouring, cover and cure for no less than 7 days. (13) Excavate the lower rock layer, carry out well wall anchor bolt and steel mesh spray anchor construction until the preset depth is reached, and set the bottom plate at the bottom; (14) Construction of the first layer of wall from the bottom plate upwards. Tie the well wall reinforcement according to the wall design drawings. Use standard steel formwork. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, check the axis, elevation and verticality. Use impermeable concrete. Pour the concrete in layers through the concrete pump. Cover and moisturize the concrete within 12 hours after pouring. Remove the formwork after the concrete strength reaches 70% of the design strength. (15) Construct the second, third and so on reinforced concrete walls in sequence. Before constructing each section of the wall, clean the concrete bonding surface of the previous section of the wall until the entire structure is completed.

2. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 1, characterized in that: In step (2), when the surrounding rock type is Class I, Class II, or Class III, the borehole design depth is taken as the depth of the overburden layer plus the diameter of the shaft.

3. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 1, characterized in that: In step (2), when the surrounding rock category is Class IV or Class V, the borehole design depth is taken as the shaft design depth plus the shaft diameter.

4. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 2, characterized in that, The specific steps (13) are as follows: (131) Excavate the lower rock layer to a depth of one unit, keeping the well wall flat during the excavation process; (132) Drill holes using a pneumatic rock drill at the designed spacing, with the hole depth as designed, and slowly insert the anchor rod into the hole, with the exposed length of the anchor rod ≥ 500 mm; (133) Cement grout is used to inject grout into the hole through the grouting pipe. After the grout is fully injected, the hole is sealed and cured for 7 days. (134) Steel mesh processing: φ6-φ8 steel bars are used and processed into steel mesh according to the design spacing. The overlap length of the mesh is ≥200mm. The mesh is tied and laid tightly against the well wall and welded to the exposed end of the anchor rod. The protective layer thickness of the mesh is ≥50mm. The mesh is laid flat and without loosening or sagging. (135) Concrete preparation: Shotcrete is used, and wet shotcrete is used. The shotcrete is sprayed from bottom to top and in layers. Vibration is carried out using the built-in vibration function of the shotcrete machine to ensure that the concrete is dense. Water curing is carried out within 12 hours after the shotcrete is completed, and the curing time is not less than 7 days. (136) Collect rock stress gauge data synchronously and compare it with preset data. If the stress value exceeds 10%, add two rows of anchor rods to the next layer. If the stress value is less than 80%, reduce one row of anchor rods to the next layer. (137) After each layer is excavated, the axis and diameter of the well wall are checked with a total station. The deviation is controlled within ±50mm. Repeat steps (131)-(137).

5. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 2, characterized in that, The specific steps of step (14) are as follows: (141) Read the rock stress gauge data in real time and compare it with the preset data. If the stress value exceeds the preset value by 10%, increase the concrete strength grade when constructing the next layer. If the stress value is within the preset range, proceed with construction according to the original design. (142) Construction of the first layer of wall from the bottom slab upwards. The wall reinforcement is tied according to the wall design drawings. Standard steel formwork is used. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, the axis, elevation and verticality are checked. Anti-seepage concrete is used. It is poured in layers by concrete pump. The concrete is covered and moisturized within 12 hours after the concrete is poured. The formwork is removed after the concrete strength reaches 70% of the design strength.

6. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 5, characterized in that, In step (142) or step (15), rock-embedded anti-buoyancy components are installed on the wall of the shaft, and the net circumferential spacing of the rock-embedded anti-buoyancy components is 3 meters.

7. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 3, characterized in that, The specific steps (13) are as follows: (131) Excavate the lower rock layer to a depth of one unit, keeping the well wall flat during the excavation process; (132) Drill holes using a pneumatic rock drill at the designed spacing, with the hole depth as designed, and slowly insert the anchor rod into the hole, with the exposed length of the anchor rod ≥ 500 mm; (133) M30 cement grout was used to inject grout into the hole through the grouting pipe. After the grouting was full, the hole was sealed and cured for 7 days. (134) Steel mesh processing: φ6-φ8 steel bars are used and processed into steel mesh according to the design spacing. The overlap length of the mesh is ≥200mm. The mesh is tied and laid tightly against the well wall and welded to the exposed end of the anchor rod. The protective layer thickness of the mesh is ≥50mm. The mesh is laid flat and without loosening or sagging. (135) Concrete preparation: Shotcrete is used, and wet shotcrete is used. The shotcrete is sprayed from bottom to top and in layers. Vibration is carried out using the built-in vibration function of the shotcrete machine to ensure that the concrete is dense. Water curing is carried out within 12 hours after the shotcrete is completed, and the curing time is not less than 7 days. (136) Collect rock stress gauge data synchronously and compare it with preset data. If the stress value exceeds 5%, add two rows of anchor rods to the next layer. If the stress value is less than 80%, reduce one row of anchor rods to the next layer. (137) After each layer is excavated, the axis and diameter of the well wall are checked with a total station. The deviation is controlled within ±50mm. Repeat steps (131)-(137).

8. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 7, characterized in that, The specific steps of step (14) are as follows: (141) If the stress value exceeds the preset value by 5%, the concrete strength grade shall be increased; if the stress value is within the preset range, construction shall be carried out according to the original design. (142) Construction of the first layer of wall from the bottom slab upwards. The wall reinforcement is tied according to the wall design drawings. Standard steel formwork is used. The formwork height is as designed. The formwork is tightly spliced. After the formwork is installed, the axis, elevation and verticality are checked. Anti-seepage concrete is used. It is poured in layers by concrete pump. The concrete is covered and moisturized within 12 hours after the concrete is poured. The formwork is removed after the concrete strength reaches 70% of the design strength.

9. The construction method for vertical shaft structures of hydraulic tunnels applied to soil and rock strata according to claim 3, characterized in that, In step (14) or (15), the piles and the underground reinforced concrete wall are connected by welding.

10. A vertical shaft structure for hydraulic tunnels applied in soil and rock strata as described in claim 2 or 3, characterized in that: The structure includes a shaft body, with several piles surrounding the shaft body. Several rock stress testing boreholes are located around the piles, and rock stress sensors at different depths are installed in the rock stress testing boreholes. The rock stress sensors are connected to a controller via signal lines. The piles pass through soil layers, Class IV and Class V surrounding rock strata in sequence. A base plate is installed at the bottom of the shaft body, and a reinforced concrete wall is installed on the base plate, extending to the upper soil layer. Several waist beams supporting the piles are installed in sequence along the depth direction in the soil layer. The reinforced concrete wall is anchored to the Class I, Class II and Class III surrounding rock strata by rock-embedded anti-buoyancy components.

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