Construction method and construction equipment for precision-controlled vertical tunneling deep and large vertical shaft

Abstract

The application discloses a construction method and construction equipment for precision control of a vertical tunneling type deep and large vertical shaft, and relates to the technical field of deep and large vertical shaft construction. When a deep and large vertical shaft is constructed by using a traditional open cut method or a caisson method, there are problems of difficult control of a sinking posture, large side friction resistance, poor structural integrity and insufficient process coordination. The application comprises the following steps: performing foundation reinforcement and constructing a top ring beam; installing a prefabricated steel blade foot ring and a starting pipe piece provided with a sensing and grouting system; installing a suspension system and a vertical tunneling host; starting the host to perform cutting, simultaneously controlling shaft sinking through the suspension system, and synchronously injecting drag reduction mud outside the shaft wall; sinking a pipe piece height every time, assembling a new pipe piece at a shaft head, and cyclically operating until a design depth; and finally performing underwater bottom sealing and wall back grouting replacement. The technical scheme realizes accurate dynamic control of the sinking posture of the shaft, reduces the side wall friction resistance, ensures the structural integrity and waterproofness, has high construction precision, good safety, high efficiency and small influence on the surrounding environment.

Description

Technical Field

[0001] This invention relates to the field of deep shaft construction technology, and in particular to a construction method and equipment for precision-controlled vertical excavation of deep shafts. Background Technology

[0002] As urban underground space development moves towards greater depth and scale, the demand for large-diameter (typically 16 meters or more) and deep (over 50 meters) shafts for applications such as rail transit, integrated utility tunnels, underground storage tanks, and energy transmission is increasing. These deep and large shafts are often located in urban built-up areas with complex surrounding environments, high groundwater levels, and variable geological conditions, placing extremely high demands on the safety, precision, efficiency, and environmental friendliness of construction technologies.

[0003] Traditional methods for constructing deep vertical shafts mainly include open-cut excavation and caisson methods. Open-cut excavation requires excavating large-area foundation pits, involves significant support work, and causes substantial disturbance to the surrounding soil. Furthermore, its implementation in urban centers often faces challenges such as difficulties in land acquisition and demolition, and significant traffic congestion. While caisson methods involve underground construction, the lateral friction between the shaft wall and the soil increases dramatically and non-linearly with depth when sinking ultra-deep shafts, leading to difficulties in sinking. Simultaneously, sudden sinking and tilting are prone to occur during sinking, making attitude control and correction difficult, resulting in high construction risks.

[0004] To overcome the limitations of traditional methods, mechanical shaft construction technology has emerged. It uses specialized shaft excavation equipment to achieve mechanized operations for excavation, slag removal, and support, and has advantages such as fast construction speed, fewer workers, and relatively high safety. However, existing mechanical methods still face several key technical bottlenecks when applied to ultra-large diameter and ultra-deep vertical shafts: First, as the weight and depth of the shaft increase, maintaining the dynamic balance and vertical accuracy of the massive shaft during the sinking process becomes extremely difficult. The coordination of the suspension system's force system and the matching control between the ground reaction force are complex, easily leading to shaft deviation. Second, the high ground stress and high water pressure environment at depth result in enormous frictional resistance between the shaft wall and the surrounding soil, which is difficult to overcome by self-weight alone, leading to low sinking efficiency or even stagnation. Third, the deep water and soil pressure poses a severe challenge to the shaft wall structure, especially the rigidity, waterproof sealing, and long-term stability of weak links such as the launching and receiving sections. Fourth, the overlapping operations of multiple processes such as tunneling, slag removal, segment assembly, backfill grouting, and attitude measurement result in insufficient system integration and intelligent collaborative control, affecting overall construction efficiency and accuracy.

[0005] Therefore, there is an urgent need for a deep and large vertical shaft construction method that can achieve high-precision vertical control, effectively reduce sinking resistance, ensure overall structural safety, and realize intelligent collaboration of multiple processes. Summary of the Invention

[0006] The technical problem to be solved and the technical task proposed by this invention is to improve and refine existing technical solutions, and to provide a construction method and equipment for precision-controlled vertical excavation of deep shafts, so as to achieve high precision, high safety and high efficiency in the construction of deep shafts, and to effectively control the impact on the surrounding environment. To this end, this invention adopts the following technical solution.

[0007] A method for constructing a precision-controlled vertical excavation deep shaft, characterized by the following steps: 1) Construction foundation reinforcement piles, bored piles and reinforced concrete top ring beams, with embedded parts pre-embedded in the top ring beams to connect the suspension system and the main lifting system; 2) Install prefabricated steel blade foot rings on the inner side of the top ring beam, and install multiple rings of prefabricated concrete starting section segments on them to form the starting section well wall. The main unit fixing seat is preset on the inner wall of the starting section segment. 3) Install the suspension system and sinking unit on the top ring beam and connect them with the steel cutting edge foot ring. Hoist the vertical tunneling main unit into the well and fix it to the main unit fixing seat. Install the ground supporting system. 4) Start the vertical tunneling machine to cut the soil at the bottom of the well and remove the slag through the mud circulation system. At the same time, control the suspension system and sinking unit to lower the steel strands to sink the well. Simultaneously, inject drag-reducing mud into the outside of the well wall to form a mud sleeve. 5) After each ring of tunnel segments is lowered to a certain height, new precast tunnel segments are assembled at the wellhead and connected to the already lowered well casing. Repeat steps 4) and 5) until the design depth is reached. 6) After the shaft is lowered into place, clean the bottom of the shaft and use the guide pipe method to pour underwater sealing concrete; 7) Inject cement slurry into the mud jacket from bottom to top through the grouting holes of the tunnel lining to replace the drag-reducing mud; 8) Drain the water from the well and construct the inner lining wall and base slab.

[0008] This method effectively solves the core problems in the construction of deep and large vertical shafts, such as difficulty in controlling the shaft attitude, high sinking resistance, insufficient structural integrity, and poor coordination among multiple processes, through a continuous process of "foundation reinforcement - initial installation - tunneling and sinking - segment extension - final sealing". It achieves safety, precision and efficiency in the construction process.

[0009] As a preferred technical means: In step 1), the foundation reinforcement piles are multi-ring triaxial mixing piles, arranged in a combination of shallow and deep layers. The shallow reinforcement zone is within 3m below the ground surface, and the deep reinforcement zone is from 3m below the ground surface to a predetermined depth. The bored piles are evenly distributed around the perimeter of the well shaft. This combination of shallow and deep reinforcement allows for differentiated treatment of soil at different depths, forming a continuous and dense three-dimensional water-stop curtain that effectively isolates groundwater. The evenly distributed tension piles provide a stable foundation for the top ring beam and subsequent equipment, and can reliably resist the buoyancy of groundwater during construction and use, ensuring structural stability in the initial stage.

[0010] As a preferred technical means: In step 2), the steel cutting edge ring is composed of multiple steel cutting edges spliced ​​circumferentially. It has an internal cavity filled with concrete, a grout stop plate on its lower outer side, and a monitoring slot for installing an earth pressure sensor on its lower inner side. This allows for real-time monitoring of the soil pressure at the cutting edge. After the initial segment is assembled, concrete is backfilled into the cavity of the steel cutting edge ring. The splicing design facilitates transportation and installation; the concrete backfilling of the internal cavity significantly increases the counterweight at the beginning of the wellbore, improving stability during the initial sinking phase; the grout stop plate on the outer side effectively prevents drag-reducing mud from flowing into the well from the bottom, ensuring a safe working environment; and the earth pressure sensor installed in the monitoring slot on the inner side enables real-time monitoring of the earth pressure at the cutting edge, providing crucial data support for sinking control.

[0011] As a preferred technical means: In step 4), the vertical tunneling machine is equipped with a dual-axis tilt sensor, and a skewing tube is installed on the shaft wall for real-time monitoring of the shaft's verticality. When the monitoring data deviates from the preset value, the sinking attitude is corrected by adjusting the tension of each steel strand in the suspension system or by using directional over-excavation. A closed-loop attitude control system of "monitoring-feedback-control" is constructed, which can sense the shaft's tilt in real time and dynamically, and achieve precise and rapid correction by actively applying correction force or by local over-excavation to reduce drag, thereby controlling the vertical accuracy of the shaft within an extremely high standard.

[0012] As a preferred technical means: In step 4), the drag-reducing mud injected into the outer side of the well wall is bentonite slurry, the injection pressure is 0.2MPa-0.5MPa, and the injection volume is controlled at 2-3 times the construction voids. The bentonite slurry can form a stable and lubricated "mud sleeve" outside the well wall, transforming the solid friction between the well wall and the soil into liquid friction, significantly reducing side friction resistance; the clearly defined pressure and injection volume control range ensures that the mud sleeve can be formed completely and continuously, effectively reducing drag without damaging the formation due to excessive pressure or resulting in poor performance due to insufficient grouting.

[0013] As a preferred technical means: In step 5), a hand hole is provided on the outer arc surface of the precast segment. The connecting bolt is inserted into the hand hole from the outside and tightened. After tightening, the hand hole is sealed with filling material. Multiple sealing and water-stopping components are provided between the segments. All connection operations are carried out on the outside of the segment, eliminating the need for high-strength bolt operations inside the narrow well shaft, which greatly improves the safety and construction efficiency of the assembly operation and reduces the labor intensity of workers.

[0014] As a preferred technical means, the sealing and water-stopping components include multiple EPDM rubber sealing gaskets and water-swellable water-stop strips installed between the segment circumferential joints. Sand-blocking strips are installed on the water-facing side of the sealing gaskets. The segments are connected by diagonal bolts, and the segment rings are connected by long bolts. These multiple sealing lines constitute a reliable joint waterproofing system, effectively resisting high water pressure at depth. The sand-blocking strips prevent mud and sand from intruding into the sealing surface. The combination of diagonal and long bolts ensures the strength and integrity of the segment ring and longitudinal joint connections, allowing the well wall structure to evenly withstand enormous water and soil pressure.

[0015] As a preferred technical approach: In step 6), the underwater sealing concrete is poured using the tremie pipe method, with multiple tremie pipes symmetrically arranged. During the pouring process, the depth of the tremie pipes embedded in the concrete is maintained at 2m-4m. The symmetrical arrangement ensures that the concrete can be evenly distributed throughout the entire bottom area of ​​the well; strictly controlling the embedment depth of the tremie pipes in the concrete can effectively prevent mud entrapment during the pouring process, ensuring that the bottom sealing concrete is poured in a uniform, dense, and layer-free manner, forming a reliable bottom seal and load-bearing structure.

[0016] As a preferred technical approach: In step 7), grouting replacement is carried out using a bottom-up relay grouting method, with the grouting pressure controlled between 0.3 MPa and 0.8 MPa. Relay grouting ensures that the cement grout completely and thoroughly replaces the drag-reducing mud in the annular gap, avoiding leaving voids; reasonable pressure control ensures that the grout fully fills the structural voids, forming a permanent reinforcement layer, while also preventing excessive pressure from damaging the segment structure.

[0017] A method for constructing a precision-controlled vertical tunneling deep shaft includes a precision-controlled vertical tunneling deep shaft construction equipment, comprising: Vertical tunneling machine, used for cutting the soil at the bottom of the well; The mud-water separation station is connected to the slurry discharge pipeline of the vertical tunneling machine and is used to separate the slag and soil from the mud-water. The suspension system and sinking unit are connected between the top ring beam and the steel blade foot ring, and are used to control the sinking speed and attitude of the well shaft; The hydraulic station and power supply cabinet provide power to the entire system; Pipeline transport unit for transporting water, electricity, slurry, and gas; The main winch is used for hoisting equipment and tunnel segments; The control room is used to centrally monitor and control the tunneling, sinking, grouting, and assembly processes. It realizes the mechanization, automation, and intelligent linkage of core processes such as tunneling, slag removal, sinking, attitude control, segment assembly, and backfill grouting, and is a key material guarantee for the efficient, precise, and safe implementation of the aforementioned construction methods.

[0018] Beneficial effects: 1. By integrating the collaborative operation mode of "active control of suspension system" and "milling by vertical tunneling host", a closed-loop attitude control system was constructed. The suspension system can accurately control the sinking speed and force balance, and the tunneling host has directional over-excavation capability. Combined with real-time tilt angle and inclination monitoring, dynamic and real-time correction can be achieved during the sinking process. This method strictly controls the verticality deviation of ultra-large diameter and ultra-deep vertical shafts to within 8‰, effectively solving the major technical problems of easy deviation and difficult correction in traditional caisson method, and realizing high-precision and controllable sinking of deep and large vertical shafts.

[0019] 2. By adopting the technology of "synchronous injection of high-performance drag-reducing mud", bentonite slurry with a specific ratio is continuously injected into the annular gap outside the well wall through the grouting holes of the segments while the well is sinking, forming a complete and stable "mud sleeve". This mud sleeve transforms the solid friction between the well wall and the soil into liquid lubrication, reducing the side friction resistance by about 30%-50%, which greatly reduces the side friction resistance of ultra-deep sinking. This overcomes the sinking difficulty or stagnation caused by the nonlinear increase of friction resistance with increasing depth, and ensures the feasibility of ultra-deep sinking.

[0020] 3. A composite lining structure of "precast concrete segments + grouting replacement" is adopted. The factory-precast segments have high precision and strength, and the joints are equipped with multiple elastic sealing gaskets and water-swellable strips, ensuring reliable waterproofing. After sinking, pressure grouting from bottom to top replaces the temporary drag-reducing mud with a permanent cement grout reinforcement layer. This reinforcement layer not only fills the structural voids but also bonds tightly with the stratum, forming a uniform load-bearing arch, which greatly improves the overall rigidity, impermeability, and long-term stability of the well wall structure under deep, high water and soil pressure.

[0021] 4. Key processes such as tunneling, muck removal, segment assembly, attitude control, and backfill grouting are highly integrated into a dedicated equipment system, and centrally monitored and coordinated through a central control room. This changes the traditional extensive operation mode of multiple trades relying on manual labor, improves the level of mechanization, integration, and intelligence in construction, and realizes the streamlined and standardized construction process. Mechanized tunneling and assembly significantly improve construction efficiency and safety, while intelligent monitoring and control ensure construction accuracy and reliability, reducing safety risks and reliance on skilled workers.

[0022] 5. By deploying multiple sensors on the cutting edge, segments, and equipment, and combining them with an automated control system, real-time sensing and feedback of key parameters such as sinking attitude, ground pressure, and grouting pressure were achieved. Construction decisions shifted from relying on experience-based judgment to being data-driven, enabling rapid and accurate responses to complex geological conditions. This achieved visualization, predictability, and controllability of the construction process, representing the development direction of intelligent construction in underground engineering.

[0023] 6. The fully underground mechanical tunneling process eliminates the need for large-scale open excavation, occupies a small area, and minimizes interference with surface traffic and surrounding buildings, significantly reducing the impact on the surrounding environment. The simultaneously formed mud jacket and subsequent cement slurry reinforcement layer effectively support the soil around the shaft, reducing stratum loss and settlement. The mud-water circulation system enables the closed-loop transportation and treatment of excavated soil, avoiding dust and mud spillage, making it environmentally friendly and particularly suitable for the construction of deep and large vertical shafts in environmentally sensitive areas such as urban centers. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the construction method process of the present invention.

[0025] Figure 2 This is a longitudinal cross-sectional schematic diagram of the well shaft structure under the construction state of the present invention.

[0026] Figure 3 This is a schematic diagram of the operation of the precision-controlled vertical tunneling deep shaft construction equipment in this invention.

[0027] Figure 4 This is a schematic diagram of the steel blade foot ring in this invention.

[0028] In the diagram: 1. Top ring beam; 101. First embedded part; 102. Second embedded part; 2. Segment; 3. Drilled pile; 4. Steel cutting edge foot ring; 401. Monitoring groove; 402. Grout stop plate; 403. Reinforcing rib plate; 404. Sleeve; 405. Shear pin; 406. Pouring hole; 407. Wide pouring waist hole; 408. Top surface vent; 409. Ventilation hole between slabs; 5. Triaxial mixing pile; 6. Water level gauge; 7. Vertical tunneling machine; 8. Slurry separation station; 9. Suspension system and sinking unit; 10. Hydraulic station and power cabinet; 11. Pipeline transportation unit; 12. Control room. Detailed Implementation

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0030] This embodiment uses the construction of a working shaft in a power tunnel project as an example to illustrate the construction method of the present invention in detail. The working shaft has an excavated inner diameter of 18.2m, a wall thickness of 0.7m, and a designed depth of 38.6m, and is constructed using a precision-controlled vertical excavation process.

[0031] This embodiment describes a construction method for a precision-controlled vertical tunneling deep shaft, implemented using precision-controlled vertical tunneling deep shaft construction equipment, such as... Figure 3 As shown, the device includes: Vertical tunneling machine 7 is used to cut the soil at the bottom of the well; The mud-water separation station 8 is connected to the slurry discharge pipeline of the vertical tunneling host 7 and is used to separate the slag and soil from the mud-water. The suspension system and sinking unit 9 are connected between the top ring beam 1 and the steel blade foot ring 4, and are used to control the sinking speed and attitude of the well shaft; The hydraulic station and power cabinet 10 provide power to the entire system; Pipeline transport unit 11 is used to transport water, electricity, mud and gas; The main winch is used for hoisting the equipment and tunnel segment 2; Control room 12 is used to centrally monitor and control the tunneling, sinking, grouting and assembly processes.

[0032] like Figure 1 The diagram shows the process flow of the construction method of the present invention. The following is a detailed description of each step.

[0033] S1: Foundation reinforcement and construction of top ring beam 1 like Figure 2 As shown, this step follows the construction logic of "first foundation reinforcement and core support, then perimeter enclosure". First, the foundation reinforcement of the three-axis mixing piles 5 and the construction of the bored piles 3 are carried out, followed by the construction of the top ring beam 1.

[0034] Construction of Tri-axis Mixing Piles 5: At the location of the shaft to be constructed, φ850@600 (the diameter of a single tri-axis mixing pile is 850mm, and the center-to-center spacing between piles is 600mm) tri-axis mixing piles 5 are used to reinforce the foundation within a 3-meter radius around the shaft and to a certain depth below the bottom of the shaft. A "deep and shallow combination" arrangement is adopted, with the area within 3m below the ground surface being the weak reinforcement zone, and the area from 3m below to 19.9m being the strong reinforcement zone. The tri-axis mixing piles 5 use P.O42.5 grade ordinary Portland cement with a cement content of 20%, a water-cement ratio controlled at 1.2-1.5, and a slurry specific gravity of 1.29-1.37g / cm³. During construction, after the pile driver is in place, the verticality is adjusted to below 1 / 200, the sinking speed is controlled at 0.5-0.8m / min, and the lifting speed is controlled at 0.5-1.5m / min. After the drill rod is driven to the design elevation, mixing and grouting continue for 1-2 minutes to ensure thorough mixing of the soil at the pile bottom with the cement grout. Then, the drill rod is rotated in the opposite direction to raise it until it is about 50cm from the ground or at the design elevation of the pile top, at which point the grouting pump is shut off. The three-axis mixing pile 5 uses a skip-driving method to ensure the continuity of the reinforcement and the construction quality of the joints, forming a continuous and dense three-dimensional water-stop curtain.

[0035] Construction of Bored Shaft 3: After the triaxial mixing pile 5 reaches a certain strength, the construction of bored shaft 3 will proceed immediately. Sixteen φ1000 bored shaft 3s, each 55m long, will be constructed around the shaft perimeter as pull-out piles, evenly distributed along the shaft's outer edge to resist groundwater buoyancy and provide foundation support for subsequent equipment. During the construction of bored shaft 3, a water level gauge 6 for monitoring groundwater levels must be pre-embedded simultaneously. Bored shaft 3 will be constructed using a mud-wall drilling process, with the mud specific gravity controlled at 1.25-1.30 and the viscosity at 18-22s. After drilling, the quality of the borehole will be inspected using a borehole caliper and inclinometer to ensure verticality is less than 1 / 200 and sediment thickness is no more than 200mm. The reinforcing cage will be fabricated in sections on-site, with the main reinforcement using 10d single-sided full welding. The allowable deviation for the main reinforcement spacing is ±10mm, and the allowable deviation for the stirrup spacing is ±20mm. Underwater concrete pouring uses a φ200mm guide pipe. The initial pouring volume ensures that the guide pipe is buried in the concrete to a depth of not less than 1m. Pouring is carried out continuously, and the pipe is pulled out as it is poured. The burial depth of the guide pipe is maintained at 2m-4m.

[0036] Construction of Top Ring Beam 1: A reinforced concrete top ring beam 1 with dimensions of 3m × 3m, an inner diameter of 18.4m, and an outer diameter of 24.4m is constructed at the top of the reinforced area. Before construction, a working pit with a depth of 3.25m is excavated, and a 25cm thick plain concrete cushion layer is poured. The pile heads of bored piles 3 are removed, and the pile head reinforcement is bent into a trumpet shape to connect with the top ring beam 1. The top ring beam 1 is pre-embedded with a first embedded part 101 for connecting the suspension system and a second embedded part 102 for connecting the main engine lifting system. At the same time, a ring of Type IV Larssen steel sheet piles with a pile length of 12m is driven around the perimeter for retaining stability. In this example, the main engine lifting system is an integrated system including the main engine winch, the suspension system, and the sinking unit 9.

[0037] S2: Installation of cutting edge ring and starting structure Steel cutting edge foot ring 4 installation: Prefabricated steel cutting edge foot ring 4 is installed on the inner side of the top ring beam 1. The steel cutting edge foot ring 4 is composed of 8 steel cutting edges spliced ​​together circumferentially, such as... Figure 4As shown, the cross-section is wedge-shaped, with a 60° cutting angle on the inner side of the bottom of the steel cutting edge, which facilitates cutting the soil and guiding the well shaft to sink vertically. The interior is equipped with a cavity for filling with concrete. By pouring concrete into the cavity, the counterweight at the bottom of the well shaft is increased, improving the sinking stability. At the same time, a reinforcing rib plate 403 is installed in the cavity to ensure structural rigidity. The top is equipped with longitudinal bolt holes, shear pin holes, and a pre-embedded sleeve 404 for connecting with the starting section segment 2 and the shear pin 405 to ensure the integrity of the circumferential and longitudinal connections. The steel cutting edge ring 4 is equipped with a φ150 pouring hole 406 and a 60mm wide pouring waist hole 407 for pouring cavity concrete. The top of the steel cutting edge ring 4 has four top surface vent holes 408 between every two radial ribs and 100mm radius inter-plate vent holes 409 between the circumferential ribs to ensure compact pouring. A rubber grout stop plate 402 is installed on the lower outer side of the steel cutting edge ring 4 to prevent drag-reducing mud from entering the well from the bottom. A monitoring groove 401 is installed on its lower inner side for installing an earth pressure sensor to monitor the earth pressure at the cutting edge in real time. The radial thickness of the steel cutting edge ring 4 is greater than the thickness of the starting segment segment 2. Its inner surface is flush with the inner surface of the starting segment segment 2, while its outer surface protrudes beyond the outer surface of the starting segment segment 2. During installation, the steel cutting edge is lifted into the working pit one by one using a crane, positioned and assembled, riveted together into a ring, welded and fixed, and then subjected to flaw detection.

[0038] Installation of the starting segment 2: Three rings of precast concrete starting segments 2 are installed sequentially on the steel cutting edge ring 4. Each ring of segment 2 consists of 8 segments 2 assembled circumferentially. The segment 2 is 2m wide and 0.7m thick, with a concrete strength grade of C60 and a permeability grade of P12. First, the first ring of starting segments 2 is assembled on the cutting edge ring and secured with circumferential bolts. Then, the second ring of starting segments 2 is assembled with staggered joints, with the joints of adjacent segments 2 offset from the first ring by 18°. The third ring of starting segments 2 is then assembled with staggered joints in the same manner. The inner wall of the starting segment 2 is pre-installed with a main unit mounting base for installing the subsequent vertical tunneling main unit 7.

[0039] Two EPDM rubber gaskets and water-swellable sealing strips are installed between the circumferential joints of segment 2. A sand-blocking strip is installed on the water-facing side of the outer gasket to ensure waterproofing of the joint. The two segments are connected by T39 oblique bolts, and the rings are connected by M48 long bolts. Hand holes are provided on the outer arc surface of precast segment 2. Bolts are inserted from the outside of segment 2 and tightened in the hand holes. After tightening, the hand holes are filled with quick-setting cement.

[0040] After the initial segment 2 is installed, concrete is backfilled into the cavity of the steel blade foot ring 4 to increase the counterweight at the bottom of the shaft and improve stability during sinking.

[0041] S3: Installation of precision-controlled vertical tunneling equipment for deep shaft construction. This equipment includes a suspension system, a vertical tunneling main unit 7, and a ground support system. Installation of the suspension system and sinking unit: A suspension system consisting of eight sets of 500t hydraulic jacks and steel strands, along with the linked sinking unit, is installed on the top ring beam 1. The eight suspension units are evenly distributed around the circumference of the top ring beam 1. Each suspension unit is connected to anchors on the steel cutting edge foot ring 4 via steel strands. The steel strands enter through the upper outer groove on the outer side of the steel cutting edge foot ring 4 and exit through the lower inner groove, forming a reliable connection. The sinking unit is equipped with a hydraulic system that works in conjunction with the main unit to assist in controlling the sinking speed and attitude of the wellbore. After installation, pre-tightening and trial lifting are performed to verify the system's stability.

[0042] Vertical tunneling machine (VTOL) main unit 7 installation: The VTOL main unit 7 is hoisted into the shaft by a main unit winch. The main unit winch is responsible for the lifting, lowering, and hoisting operations of the tunneling machine and its components, ensuring safety during the installation process. The main unit is the core equipment for shaft excavation, including a cutting system, a propulsion system, and a support system, used for efficient cutting and rock breaking of the soil at the bottom of the shaft. The VTOL main unit 7, assembled on the ground, is hoisted into the shaft as a whole, and the movable seat on the main unit support arm is connected to the main unit fixed seat pre-embedded in the inner wall of the starting segment 2 and locked in place. This VTOL main unit 7 is a customized piece of equipment, with an alloy cutting head installed on the milling head, capable of performing upward, downward, and rotational movements to complete the excavation of the entire shaft cross-section.

[0043] Ground Support System Installation: Subsequently, the ground support system is installed, including: a slurry separation station 8, used to separate solid particles from the tunneling slurry, ensuring the cleanliness of the circulation system and improving construction efficiency; a sinking unit equipped with a hydraulic system connected to the main unit, used to control the settlement of the tunneling equipment, ensuring shaft stability, preventing collapse, and improving construction safety; a hydraulic station and power cabinet 10, used to provide hydraulic power and electrical control, ensuring the normal operation of the tunneling machine and efficient construction; a pipeline delivery unit 11, used to deliver water, electricity, slurry, and gas, maintaining the normal operation of the tunneling machine and ensuring construction continuity; and a control room 12, used to monitor and control the tunneling process, realizing automated operation and improving construction intelligence and safety. All hydraulic and electrical pipelines are connected, and the entire machine is commissioned.

[0044] S4: Precision control of vertical tunneling and synchronous sinking Excavation: The vertical tunneling machine 7 is started. The milling head of the vertical tunneling machine 7 cuts the soil at the bottom of the well in a preset sequence, with each cut depth controlled at 80mm-100mm. The cut soil is mixed with the mud in the well and transported by the slag discharge pump through the slurry discharge pipeline to the surface mud-water separation station 8 for separation. In the mud circulation system, the slag discharge pump is driven by a 150kW variable frequency drive, which can achieve a constant torque output of 5-50Hz, and the pump outlet flow rate adjustment range is 0-800m³ / h. The slurry inlet pump is adjusted synchronously to maintain a stable liquid level in the well, keep the pressure in the well balanced with the groundwater pressure, and ensure that the mud level in the well is not lower than the groundwater level by 1m.

[0045] Sinking Control: After completing one cutting stroke, the steel strand is released at a speed of 10mm / min-20mm / min through coordinated control of the suspension system and the sinking unit. The weight of the shaft and equipment causes the entire structure to sink by the same stroke. During this process, the vertical tunneling host 7 is equipped with a dual-axis tilt sensor, and an inclinometer is installed on the shaft wall. The verticality of the shaft is monitored in real time through the dual-axis tilt sensor and the inclinometer. If deviation occurs, the tension of the steel strand on the deviated side in the suspension system is adjusted, or the sinking unit provides auxiliary downward pressure on the opposite side of the deviation for dynamic correction. At the same time, the shaft attitude is adjusted by controlling the release of the steel strand to ensure that the vertical accuracy of the shaft is controlled within 8‰.

[0046] Simultaneous grouting: While the well is sinking, bentonite slurry with a specific gravity of 1.05-1.10 and a viscosity of 22s-30s is injected into the outer gap of the wellbore at a pressure of 0.2MPa-0.5MPa through the grouting holes pre-reserved on the initial section and subsequent standard rings, forming a mud sleeve to effectively reduce side friction. The grouting pressure is dynamically adjusted according to the real-time monitoring of formation pressure and wellbore sinking resistance to ensure the continuity and integrity of the mud sleeve. The grouting volume is controlled at 2-3 times the construction voids until the bentonite slurry overflows from the wellhead.

[0047] S5: Segment 2 Assembly and Structural Extension Once the submersion depth reaches the height of segment 2 (2m), excavation is halted. The new precast standard segment 2 is then transported in sections to the shaft opening using the main winch, where assembly workers assemble it on the shaft platform. During assembly, segment 2 is first positioned, circumferential bolts are inserted and initially tightened. After the entire ring is formed, longitudinal bolts are inserted to connect the newly assembled segment 2 ring to the previous segment 2 ring. All bolts are inserted through the manholes on the outside of segment 2 and tightened to the designed torque using a pneumatic wrench. After tightening, the manholes are filled with quick-setting cement to ensure a tight seal.

[0048] Repeat steps S4 and S5 for tunneling, sinking, and assembly, assembling one ring of segment 2 every 2 meters of sinking, until the shaft sinks to the designed depth of 38.6 meters. Throughout the sinking process, drag-reducing mud is continuously injected through the pre-set grouting holes of the third ring of segment 2 to ensure the integrity of the mud sleeve on the outside of the shaft wall.

[0049] S6: Bottom reinforcement and sealing construction After the shaft is lowered into place, the bottom of the shaft is cleaned using the milling head of the vertical tunneling machine 7, removing silt and debris from the cutting edge. Then, underwater sealing concrete is poured using the tremie method through the shaft opening pouring platform, with a sealing thickness of 6m. The concrete strength grade is C20, the slump is controlled at 220mm-240mm, and retarders and micro-expansion agents are added, with an initial setting time of not less than 6 hours.

[0050] During pouring, six guide pipes with an inner diameter of 300mm are symmetrically arranged, with the guide pipes inserted to a depth of 0.3m-0.4m from the base surface. During the concrete pouring process, the guide pipes are kept buried at a depth of 2m-4m. The concrete spreads outwards during the pouring process, filling the excavated area and forming a solid bond with the steel cutting edge ring 4, the starting segment 2, and the surrounding strata.

[0051] S7: Backwall Grouting Replacement After the bottom sealing concrete reaches its design strength, cement grout with a water-cement ratio of 1:1 is injected from bottom to top into the gaps on the outer side of the well wall through the grouting holes reserved on the precast segment 2, replacing the previously injected bentonite slurry. During grouting replacement, a plunger pump is used for grouting, and the grouting pressure is controlled at 0.3MPa-0.8MPa.

[0052] The grouting sequence proceeds from bottom to top. Grouting begins at the grouting holes of the third ring segment 2. Once the grout reaches the eighth ring segment 2, grouting continues in the eighth ring, progressing upwards until grout appears at the ground level. During the grouting process, pressure sensors monitor the grouting pressure in real time to prevent excessive pressure from damaging the segment 2 structure. The grouting volume is controlled at 110%-130% of the theoretical structural voids to ensure the gaps are completely and densely filled with cement grout.

[0053] S8: Internal Structure Construction After the grouting slurry behind the wall solidifies, the vertical tunneling machine 7 is lifted out of the working face and then lifted vertically upward along the shaft until it is completely lifted out of the shaft.

[0054] A high-powered water pump was used to drain the accumulated water from the well shaft, creating a dry working environment. A reinforced concrete base slab, 2m thick, was constructed on the bottom sealing structure, with the reinforcing bars connected to the pre-embedded connectors within the first ring segment 2. Finally, an inner lining wall was constructed on the inner wall of the well shaft, connected to the precast segment 2 via pre-embedded connectors to form a composite lining structure, completing the internal structure construction of the shaft.

[0055] Thus, the construction of the precision-controlled vertical excavation deep shaft in this embodiment is completed.

[0056] The above are specific embodiments of the present invention, which demonstrate the outstanding substantive features and significant progress of the present invention. Based on the actual needs of use, equivalent modifications in shape, structure, etc., can be made to it according to the teachings of the present invention, and all such modifications are within the scope of protection of this solution.

Claims

1. A construction method for a precision-controlled vertical excavation deep shaft, characterized in that, Includes the following steps: 1) Construction foundation reinforcement piles, bored piles and reinforced concrete top ring beams, with embedded parts pre-embedded in the top ring beams to connect the suspension system and the main lifting system; 2) Install prefabricated steel blade foot rings on the inner side of the top ring beam, and install multiple rings of prefabricated concrete starting section segments on them to form the starting section well wall. The main unit fixing seat is preset on the inner wall of the starting section segment. 3) Install the suspension system and sinking unit on the top ring beam and connect them with the steel cutting edge foot ring. Hoist the vertical tunneling main unit into the well and fix it to the main unit fixing seat. Install the ground supporting system. 4) Start the vertical tunneling machine to cut the soil at the bottom of the well and remove the slag through the mud circulation system. At the same time, control the suspension system and sinking unit to lower the steel strands to sink the well. Simultaneously, inject drag-reducing mud into the outside of the well wall to form a mud sleeve. 5) After each ring of tunnel segments is lowered to a certain height, new precast tunnel segments are assembled at the wellhead and connected to the already lowered well casing. Repeat steps 4) and 5) until the design depth is reached. 6) After the shaft is lowered into place, clean the bottom of the shaft and use the guide pipe method to pour underwater sealing concrete; 7) Inject cement slurry into the mud jacket from bottom to top through the grouting holes of the tunnel lining to replace the drag-reducing mud; 8) Drain the water from the well and construct the inner lining wall and base slab.

2. The construction method for a precision-controlled vertical excavation deep shaft according to claim 1, characterized in that: In step 1), the foundation reinforcement piles are multi-ring triaxial mixing piles, and the arrangement is a combination of shallow and deep layers. The area within 3m below the ground is the shallow reinforcement zone, and the area from 3m below the ground to the preset depth is the deep reinforcement zone. The bored piles are evenly distributed around the perimeter of the well.

3. The construction method for a precision-controlled vertical excavation deep shaft according to claim 1, characterized in that: In step 2), the steel cutting edge ring is made up of multiple steel cutting edges spliced ​​together circumferentially. It has a cavity filled with concrete inside, a grout stop plate on its lower outer side, and a monitoring groove for installing a soil pressure sensor on its lower inner side to monitor the soil pressure at the cutting edge in real time. After the initial segment is assembled, concrete is backfilled into the cavity of the steel cutting edge ring.

4. The construction method for a precision-controlled vertical excavation deep shaft according to claim 1, characterized in that: In step 4), the vertical tunneling machine is equipped with a dual-axis tilt sensor and a skewing tube on the well wall to monitor the verticality of the well in real time. When the monitoring data deviates from the preset value, the sinking attitude is corrected by adjusting the tension of each steel strand in the suspension system or by using directional over-excavation.

5. The construction method for a precision-controlled vertical excavation deep shaft according to claim 1, characterized in that: In step 4), the drag-reducing mud injected into the outside of the well wall is bentonite slurry, the grouting pressure is 0.2MPa-0.5MPa, and the grouting volume is controlled at 2-3 times the building voids.

6. The construction method for a precision-controlled vertical excavation deep shaft according to claim 1, characterized in that: In step 5), a hand hole is provided on the outer arc surface of the precast segment. The connecting bolt is inserted into the hand hole from the outside and tightened. After tightening, the hand hole is sealed with filling material. Multiple sealing and water-stopping components are provided between the segments.

7. The construction method for a precision-controlled vertical excavation deep shaft according to claim 6, characterized in that: The sealing and water-stopping components include multiple EPDM rubber gaskets and water-swellable water-stop strips installed between the circumferential joints of the pipe segments. Sand-blocking strips are installed on the water-facing side of the gaskets. The pipe segments are connected by diagonal bolts, and the pipe segment rings are connected by long bolts.

8. The construction method for a precision-controlled vertical excavation deep shaft according to claim 1, characterized in that: In step 6), the underwater sealing concrete is poured using the tremie pipe method. Multiple tremie pipes are arranged symmetrically, and the depth of the tremie pipes embedded in the concrete is maintained at 2m-4m during the pouring process.

9. The construction method for a precision-controlled vertical excavation deep shaft according to claim 1, characterized in that: In step 7), grouting replacement is carried out using a bottom-up relay grouting method, with the grouting pressure controlled between 0.3MPa and 0.8MPa.

10. A construction device for implementing the construction method of a precision-controlled vertical excavation deep shaft as described in any one of claims 1-9, characterized in that, include: Vertical tunneling machine, used for cutting the soil at the bottom of the well; The mud-water separation station is connected to the slurry discharge pipeline of the vertical tunneling machine and is used to separate the slag and soil from the mud-water. The suspension system and sinking unit are connected between the top ring beam and the steel blade foot ring, and are used to control the sinking speed and attitude of the well shaft; The hydraulic station and power supply cabinet provide power to the entire system; Pipeline transport unit for transporting water, electricity, slurry, and gas; The main winch is used for hoisting equipment and tunnel segments; The control room is used to centrally monitor and control the tunneling, sinking, grouting, and assembly processes.

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