Semi-suspension settlement construction method for vertical shaft

Abstract

The invention relates to a vertical shaft semi-suspension settlement construction method which comprises the following steps that S1, a vertical shaft foundation pit with a certain depth is excavated firstly, a blade foot ring is placed in the foundation pit, a shaft wall ring is installed on the blade foot ring, and the blade foot ring is connected with a settlement unit outside a vertical shaft through a pull rope; and S2, the vertical shaft continues to be excavated downwards, the height of the shaft wall ring is increased in good time according to the excavation depth, then the settlement unit controls the blade foot ring and the shaft wall ring to descend towards the bottom of the vertical shaft, and a gap is reserved between the bottom of the blade foot ring and the bottom of the vertical shaft. And S3, when the pulling force applied by the blade foot ring to the settlement unit reaches the maximum bearing threshold value of the settlement unit, the settlement unit controls the blade foot ring to descend towards the bottom of the vertical shaft, so that the bottom of the blade foot ring gradually makes contact with the bottom of the vertical shaft, when the applied pulling force is smaller than the maximum bearing threshold value, the blade foot ring stops descending, and then excavation continues. And S4, the step S3 is repeated until the blade foot ring and the well wall ring descend to the designated depth. The open caisson has the advantages of a pressure open caisson and a suspension open caisson, so that the settlement is safer, and the cost is lower.

Description

Technical Field

[0001] The invention belongs to the technical field of vertical shaft construction, and in particular relates to a vertical shaft semi-suspension settlement construction method. Background Art

[0002] The main methods for constructing vertical shafts, specifically caisson descent, include gravity descent, pressure descent, and suspended descent. Gravity descent relies solely on the weight of the shaft wall during excavation, particularly during excavation of the lower rock and soil. While simple, it can be difficult to control, and is generally used for small, shallow shafts.

[0003] The pressure drop method requires setting up multiple deep anchor cables outside the well in advance. The rock and soil below the well wall are not completely hollowed out. The friction of the anchor cables is used to force the well wall to descend through multiple cylinders. The characteristic is that the controllability during descent is improved. It is suitable for vertical shafts with larger diameters and deeper shafts. In the early stage of vertical shaft descent, the guide length is short and unstable, and the expenses and costs of the anchor cables and pressure system are high.

[0004] The suspended descent method uses steel strands on the ground to hold the shaft wall. The excavated diameter at the bottom of the shaft is larger than the outer diameter of the shaft wall, with an appropriate amount of overexcavation to keep the shaft wall completely suspended. The steel strands are then controlled by a subsidence cylinder to lower the shaft. This method is characterized by a smooth descent and can even be raised when needed. However, due to the limited load-bearing capacity of the cylinder, it is not suitable for large-diameter or deep shafts, generally no larger than 20 meters. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a semi-suspension settlement construction method for a vertical shaft in response to the shortcomings of the existing technologies in terms of their respective applicability, which combines the advantages of both pressure caisson and suspension caisson methods, solves the problems of unstable descent and high cost in the early stage of the pressure settlement method, and solves the problem of poor adaptability of the suspension settlement method to large-diameter deep wells, making the settlement of the vertical shaft safer and lower-cost.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The semi-suspended settlement construction method of the vertical shaft includes the following steps: S1. First, dig a foundation pit of a vertical shaft to a certain depth, place the blade foot ring in the foundation pit of the vertical shaft, install a well wall ring on the upper part of the blade foot ring, and connect the blade foot ring to the settlement unit outside the vertical shaft through a pull rope. The settlement unit can pull the blade foot ring and the well wall ring to move up and down in the vertical shaft.

[0007] S2. Continue to excavate the rock and soil below the shaft and the shaft wall ring, increase the height of the shaft wall ring in a timely manner, and then control the blade ring and the shaft wall ring to descend to the bottom of the shaft with a gap between the bottom of the blade ring and the bottom of the shaft.

[0008] S3. Repeat step S2 until the tension applied by the blade foot ring on the settlement unit reaches the maximum load threshold of the settlement unit. The settlement unit controls the blade foot ring to descend toward the bottom of the shaft, causing the bottom of the blade foot ring to gradually contact the bottom of the shaft until the tension applied by the blade foot ring on the settlement unit is less than the maximum load threshold. The blade foot ring stops descending and then continues to dig the shaft downward.

[0009] S4. Repeat the steps of S3 until the blade foot ring and the well wall ring drop to the specified depth, and then stop digging.

[0010] In order to better realize the present invention, further optimization is made in the above structure. In step S3, the settlement unit is also provided with a minimum load threshold. When the bottom of the blade foot ring contacts the bottom of the shaft, the pulling force applied by the blade foot ring to the settlement unit should be greater than the minimum load threshold and less than the maximum load threshold.

[0011] In order to better realize the present invention, further optimization is made in the above structure, and the diameter of the vertical shaft excavation is larger than the outer diameter of the blade foot ring, so that the shaft wall ring above the blade foot ring will not contact the soil, and the soil will not have resistance to the descent of the shaft wall ring like the pressure settlement method.

[0012] In order to better implement the present invention, further optimization is made in the above structure, and the pull rope is a steel strand.

[0013] In order to better implement the present invention, further optimization is made in the above structure, and the sinking unit controls the retraction and extension of the steel strand through the sinking cylinder.

[0014] In order to better realize the present invention, further optimization is made in the above structure, and multiple sedimentation units are evenly arranged along the circumference of the shaft.

[0015] In order to better realize the present invention, further optimization is made in the above structure, and the vertical shaft is excavated by using multiple underwater tunneling machines.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The semi-suspended settlement construction method for a vertical shaft provided by the present invention combines the advantages of both pressure-drop and suspended descent methods. The maximum bearing capacity of the settlement unit is far less than the maximum weight of the shaft ring, or it can only bear the weight of 1 / 3-1 / 4 of the total length of the shaft ring, which can reduce equipment costs. In the early stages, when the shaft is relatively shallow, settlement can be controlled entirely or largely by steel strands. By using the steel strands as an aid, deflection problems will not occur, and the construction accuracy of the shaft can be effectively improved. When the shaft ring gradually increases in height and its weight exceeds the maximum tension of the settlement unit, the settlement unit cylinder will be pulled down by the shaft ring until the blade ring squeezes the rock and soil at the bottom of the well. Using the rock and soil as support, the blade ring will be subjected to an upward support force from below, bearing part of the weight of the shaft ring, thereby reducing the load and cost of the steel strand settlement unit. Moreover, in the later stages, the bearing capacity of the formation increases, the guide length of the shaft wall also increases, and the descent of the shaft ring will be more stable. Therefore, the semi-settlement method can complete the settlement of large-diameter deep shafts with fewer settlement units. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a top view of the semi-suspended settlement construction of the vertical shaft of the present invention; Figure 2 It is a side sectional view of the semi-suspension settlement construction of the vertical shaft of the present invention.

[0019] In the picture: 1-Shaft wall ring, 2-Blade foot ring, 3-Pull rope, 4-Sinking unit, 5-Underwater tunneling machine. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that, unless otherwise specified, the term "plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front," "rear," "head," "tail," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention depending on the specific circumstances.

[0023] Please combine Figure 1 and Figure 2 The semi-suspended settlement construction method for a vertical shaft provided by the present invention is similar to the suspended settlement method in that the blade ring at the bottom of the shaft wall ring is connected to the settlement unit 4 on the ground through a steel strand. The difference is that in order to reduce equipment costs, the maximum bearing capacity of the settlement unit 4 is much smaller than the maximum weight of the shaft wall, or it can only bear the weight of 1 / 3-1 / 4 of the length of the shaft wall. That is, in the early stage of construction, the construction process is the same as that of the suspended settlement method. In the later stage of construction, when the shaft is longer, the total weight of the shaft wall ring has exceeded the maximum bearing capacity of the settlement unit 4. The excess weight is borne by the soil below, while the total weight of the shaft wall in the suspended settlement method is borne by the settlement unit throughout the entire process.

[0024] The specific steps include: S1. In the preliminary preparation stage, a foundation pit of a vertical shaft of a certain depth is first excavated, and the blade foot ring 2 is placed in the foundation pit of the vertical shaft. A shaft wall ring 1 is installed on the upper part of the blade foot ring 2. The blade foot ring 2 is connected to the settlement unit 4 outside the vertical shaft through a pull rope 3. The pull rope 3 is made of steel wire rope. The settlement unit 4 can pull the blade foot ring 2 and the shaft wall ring 1 up and down in the vertical shaft.

[0025] S2, the fully suspended stage: Shaft excavation continues downward. Settling unit 4 controls blade foot ring 2 and shaft wall ring 1 to descend toward the shaft bottom, leaving a gap between the bottom of blade foot ring 2 and the shaft bottom. Shaft wall ring 1 is completely suspended. At this point, shaft wall ring 1 is relatively short and light, allowing settling unit 4 to lift the entire shaft wall weight, keeping shaft wall ring 1 and blade foot ring 2 completely suspended. This ensures shaft construction accuracy and prevents deflection.

[0026] S3, semi-suspension stage, when the tension applied by the blade foot ring 2 to the settlement unit 4 reaches the maximum load threshold of the settlement unit 4, the settlement unit 4 controls the blade foot ring 2 to descend toward the bottom of the shaft, so that the bottom of the blade foot ring 2 gradually contacts the bottom of the shaft, until the tension applied by the blade foot ring 2 to the settlement unit 4 is less than the maximum load threshold, the blade foot ring 2 stops descending, and then continues to dig the shaft downward, waiting for the next settlement of the blade foot ring 2. The settlement unit 4 is also provided with a minimum load threshold. When the bottom of the blade foot ring 2 contacts the bottom of the shaft, the tension applied by the blade foot ring 2 to the settlement unit 4 should be greater than the minimum load threshold and less than the maximum load threshold to avoid the tension being too small and causing the steel strand to loosen. At this stage, since the height of the well wall ring 1 has increased a lot, its own weight has exceeded the maximum tension of the settlement unit 4. Therefore, the settlement unit 4 only bears part of the pressure of the well wall, and the excess pressure is borne by the ground at the bottom, making the well wall ring 1 in a semi-suspension state.

[0027] Because the verticality of the shaft ring 1 is maintained during the full suspension phase, the guide length of the shaft wall is also extended during the semi-suspension phase. This ensures the verticality of the shaft ring 1 during downward movement, preventing significant deflection and thus ensuring construction accuracy. In the event that the shaft tilts during the settlement phase, the settlement is assisted by the steel strands, preventing rapid and uncontrolled deflection. Even if tilt does occur, it is easily corrected by simply digging more on the side with less settlement.

[0028] S4. Repeat the steps of S3 to ensure that the settlement unit 4 controls the blade foot ring 2 and the shaft wall ring 1 to descend to a distance of about 10CM to the bottom of the shaft each time, control the progress of each construction, and maintain the working pressure of the oil cylinder of the settlement unit 4 between 10-24MPa. The remaining load is borne by the soil under the blade foot ring 2. The automatic control system of the settlement unit 4 determines and starts descending at any time until the blade foot ring 2 and the shaft wall ring 1 descend to the specified depth, and then stops excavation.

[0029] During construction, a certain amount of over-excavation is maintained, that is, the excavated diameter is slightly larger than the outer diameter of the blade foot ring 2, to ensure that the outer wall of the well wall ring 1 above the cutting edge does not contact the soil, so as to reduce the additional friction caused by contact when the well wall ring 1 sinks.

[0030] The sinking unit 4 controls the retraction and extension of the steel strands through a sinking oil cylinder. Multiple sinking units 4 are evenly arranged along the circumference of the shaft, and the weight of the shaft wall ring 1 is distributed through multiple sinking units 4.

[0031] The suspension point on the ground (settlement unit 4) should ensure that at any time, when the supporting force of the lower part is reduced, there is still sufficient tension reserve.

[0032] During the shaft excavation construction, a plurality of underwater tunneling machines 5 are used for excavation.

[0033] In addition, the subsidence unit 4 should always maintain an appropriate descent stroke, and the final 400mm of travel in the subsidence cylinder should be reserved. As the roadheader continuously excavates the rock and soil below the blade foot, the rock and soil support surface gradually decreases, the rock and soil deform, the shaft wall drops slightly, and the oil pressure in the cylinder gradually rises. When the oil pressure approaches 24MPa, the control system opens the subsidence cylinder, and the piston descends with the shaft wall. At this point, the rock and soil bearing capacity gradually increases, and the cylinder pressure gradually decreases until it reaches 20MPa and stops descending. The specific amount of each descent is entirely determined by the oil pressure.

[0034] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. The semi-suspension settlement construction method of the vertical shaft is characterized by: The following steps are involved: S1. First, a foundation pit of a vertical shaft of a certain depth is excavated, and a blade foot ring (2) is placed in the foundation pit of the vertical shaft. A shaft wall ring (1) is installed on the upper part of the blade foot ring (2). The blade foot ring (2) is connected to a settlement unit (4) outside the vertical shaft via a pull rope (3). The settlement unit (4) can pull the blade foot ring (2) and the shaft wall ring (1) to move up and down in the vertical shaft; S2, continue to dig the rock and soil below the vertical shaft and the shaft wall ring (1), increase the height of the shaft wall ring (1) in due time, and then the settlement unit (4) controls the blade foot ring (2) and the shaft wall ring (1) to descend toward the bottom of the vertical shaft, and a gap is left between the bottom of the blade foot ring (2) and the bottom of the vertical shaft; S3, repeating the step of S2 until the tension applied by the blade foot ring (2) to the settlement unit (4) reaches the maximum load threshold of the settlement unit (4), the settlement unit (4) controls the blade foot ring (2) to descend toward the bottom of the shaft, so that the bottom of the blade foot ring (2) gradually contacts the bottom of the shaft, until the tension applied by the blade foot ring (2) to the settlement unit (4) is less than the maximum load threshold, the blade foot ring (2) stops descending, and then continues to dig the shaft downward; S4. Repeat step S3 until the blade foot ring (2) and the well wall ring (1) descend to a specified depth, and then stop excavating.

2. The semi-suspended settlement construction method of a vertical shaft according to claim 1, characterized in that: In step S3, the settlement unit (4) is further provided with a minimum load threshold. When the bottom of the blade foot ring (2) contacts the bottom of the shaft, the tension applied by the blade foot ring (2) to the settlement unit (4) should be greater than the minimum load threshold and less than the maximum load threshold.

3. The semi-suspension settlement construction method of a vertical shaft according to claim 1, characterized in that: The diameter of the vertical shaft excavation is larger than the outer diameter of the blade foot ring (2).

4. The semi-suspended settlement construction method of a vertical shaft according to claim 1, characterized in that: The pull rope (3) is a steel strand.

5. The semi-suspended settlement construction method of a vertical shaft according to claim 4, characterized in that: The sinking unit (4) controls the retraction and extension of the steel strand via a sinking oil cylinder.

6. The semi-suspended settlement construction method of a vertical shaft according to claim 1, characterized in that: A plurality of the sedimentation units (4) are evenly arranged along the circumference of the shaft.

7. The semi-suspended settlement construction method of a vertical shaft according to claim 1, characterized in that: The vertical shaft is excavated using a plurality of underwater tunneling machines (5).

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