Construction method for cutting and taking away foreign matter in front of shield tunnel

Abstract

The invention discloses a construction method for cutting and taking away foreign matters in front of a shield tunnel, which belongs to the technical field of construction, and comprises the following steps: S1, building a hoisting platform beside a dewatering well, mounting a hoisting frame above the hoisting platform, fixing a winch on the upper surface of the hoisting frame through bolts, winding a steel wire traction rope on a winding drum of the winch, the other end of the steel wire traction rope is in bolted connection with a lifting hook, and the lifting hook is moved to the position above the precipitation well; s2, a shield tunnel is formed to communicate with the dewatering well, muck and concrete in the tunnel are cleaned, and cutting equipment is pulled to conduct cutting operation on the cross-shaped impact cone; s3, cutting the cross-shaped impact cone into a plurality of groups of fragments, and welding lifting points on the fragments of each group of cross-shaped impact cone by constructors, so that the size of the cross-shaped impact cone is reduced, the weight and the size of the cross-shaped impact cone during lifting are reduced, damage to a shield tunnel and a precipitation well is reduced, and the construction efficiency is improved. And convenience is provided for the transfer operation after the cross-shaped impact cone is lifted out.

Description

A method for cutting and removing foreign objects in front of a shield tunnel Technical Field

[0001] This invention relates to the field of construction technology, specifically to a method for cutting and removing foreign objects in front of a shield tunnel. Background Technology

[0002] During the tunnel boring machine's (TBM) construction beneath the riverbed, a foreign object was discovered ahead. This object was a cross-shaped impact cone left over from previous bridge construction. Due to its large size and the fact that it was made of high-strength wear-resistant steel, the TBM's cutterhead was unable to cut it, preventing construction workers from carrying out their work and affecting the construction progress. Furthermore, the presence of the cross-shaped impact cone posed a safety hazard to the construction environment, so it was necessary to remove the underwater foreign object.

[0003] Currently, the method for handling underwater foreign objects involves creating a dewatering well above a cross-shaped impact cone in the river channel. This well is connected to the shield tunnel, and water is pumped out. Then, construction workers enter the dewatering well to weld the lifting point of the foreign object. A large lifting device is then used to connect the foreign object to the cross-shaped impact cone and lift it out of the dewatering well. However, because the cross-shaped impact cone is made of high-strength wear-resistant steel, it is quite heavy, which makes it easy for it to collide with the shield tunnel and the dewatering well during lifting. Removing it can easily damage the shield tunnel and the dewatering well. In addition, its large size after lifting makes it inconvenient to transport the cross-shaped impact cone. Therefore, we need to propose a method for cutting and removing foreign objects in front of the shield tunnel. Summary of the Invention

[0004] The purpose of this invention is to provide a method for cutting and removing foreign objects in front of a shield tunnel, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for cutting and removing foreign objects in front of a shield tunnel, comprising the following steps:

[0006] Step S1: Build a hoisting platform next to the dewatering well, install a hoisting frame on the top of the hoisting platform, and bolt a winch to the upper surface of the hoisting frame. A steel wire traction rope is wound on the drum of the winch, and a hook is attached to the other end of the steel wire traction rope. Move the hook to the top of the dewatering well.

[0007] Step S2: Connect the shield tunnel to the dewatering well, clear the slag and concrete inside the tunnel, and pull out the cutting equipment to cut the cross-shaped impact cone.

[0008] Step S3: Cut the cross-shaped impact cone into several groups of fragments, and have construction workers weld lifting points onto each group of cross-shaped impact cone fragments;

[0009] Step S4: Start the winch to unwind the wire rope. The wire rope, along with the hook, enters the dewatering well. The hook moves above the cross-shaped impact cone fragments. Construction workers connect the hook to the lifting point. Start the winch to wind up the wire rope. The wire rope lifts the cross-shaped impact cone fragments out of the dewatering well via the hook.

[0010] For example, in S3, it is necessary to cut the cross blades around the cross-shaped impact cone, measure the size of the cut cross-shaped impact cone fragments with a tape measure, weigh the cross-shaped impact cone fragments with a weighing device, and record the weight and size of each set of cut cross-shaped impact cone fragments.

[0011] For example, the right crossblade is cut three times, and the size and weight of each crossblade fragment are recorded.

[0012] For example, after cutting the right cross flange, steel pipes are immediately used to provide oblique support to the pile head. The steel pipes are at an angle of 60°-65° to the horizontal plane, and the upper end of the steel pipes is rigidly connected to the pile head through a collar-type support hoop.

[0013] For example, the remaining three sets of cross blades are cut by cutting the right cross blade, and after the cutting is completed, steel pipes are used to provide oblique support for the pile head.

[0014] For example, after the cross blade is cut, a chain hoist is used to apply preload to the impact drill bit to balance its own weight and transfer the force, and the original steel pipe support and collar support are removed.

[0015] For example, the impact cone is gradually and slowly lowered to a horizontal position using a chain hoist, and the construction workers fully weld steel lifting points at the top of the impact cone.

[0016] For example, the winch is started to lower the hook into the dewatering well. The construction workers connect the hook to the lifting point of the impact cone, start the winch to wind up the wire rope, and pull the impact cone to the wellhead of the dewatering well through the hook according to the preset path.

[0017] For example, a gantry crane is used to lower the hook into the dewatering well. The construction workers connect the hook of the gantry crane to the lifting point above the impact cone, start the gantry crane to lift the impact cone vertically through the lifting point, and slowly lift it out of the working well to the designated area on the ground.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] This invention provides a method for cutting and removing foreign objects in front of a shield tunnel. By setting up a cutting device, a cross-shaped impact cone can be cut, avoiding the need for a single integrated design and reducing its size. By welding lifting points onto the fragments of the cross-shaped impact cone, a winch can sequentially lift each set of fragments out of the dewatering well using a hook, avoiding the use of large lifting equipment and facilitating the removal of the cross-shaped impact cone. This method reduces the size of the cross-shaped impact cone, decreases its weight and dimensions during lifting, reduces damage to the shield tunnel and dewatering well, and facilitates the transportation of the removed cross-shaped impact cone.

[0020] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0021] Figure 1 is a schematic diagram of the construction steps for cutting and removing foreign objects in front of the shield tunnel according to the present invention.

[0022] Figure 2 is a schematic diagram of the structure of the first piece cut by the right cross wing plate of the present invention;

[0023] Figure 3 is a schematic diagram of the structure of the second piece cut by the right cross wing plate of the present invention;

[0024] Figure 4 is a schematic diagram of the structure of the third piece cut by the right cross wing plate of the present invention;

[0025] Figure 5 is a schematic diagram showing the connection between the dewatering well and the shield tunnel of the present invention;

[0026] Figure 6 is a schematic diagram of the cross-shaped impact cone of the present invention in a shield tunnel;

[0027] Figure 7 is a schematic diagram of the construction of the dewatering well of the present invention;

[0028] Figure 8 is a schematic diagram of the construction of the shield tunnel of the present invention.

[0029] Numbered in the diagram: 1. Cross-shaped impact cone. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please refer to Figures 1-8. This invention provides a method for cutting and removing foreign objects in front of a shield tunnel, including the following steps:

[0032] Step S1: Construct a hoisting platform next to the dewatering well. Install a hoisting frame on top of the hoisting platform. A winch is bolted to the upper surface of the hoisting frame. A steel wire traction rope is wound around the drum of the winch, and a hook is attached to the other end of the steel wire traction rope. Move the hook above the dewatering well. By constructing a hoisting platform next to the dewatering well, a stable support foundation is provided for the hoisting frame, which can effectively avoid safety hazards such as equipment shaking and tipping, and ensure the stability of the hoisting operation. Fix the hoisting frame above the platform. Utilize the rigid fixing characteristics of the bolt connection to ensure that the winch is firmly installed and to prevent equipment displacement during operation. The winch moves the hook by winding and unwinding the steel wire traction rope on the drum, accurately positioning the hook above the dewatering well, preparing for subsequent lifting of foreign objects.

[0033] Step S2: Connect the shield tunnel to the dewatering well, clear the slag and concrete in the tunnel, and pull out the cutting equipment to cut the cross-shaped impact cone. The construction workers enter the shield tunnel connected to the dewatering well with the cutting equipment. The construction workers clear the slag and concrete in the tunnel to prepare for the cutting work of the cross-shaped impact cone, avoid the slag and concrete affecting the cutting process, remove interference, and create a safe and smooth working environment for the cutting process.

[0034] Step S3: Cut the cross-shaped impact cone into several groups of fragments. Construction workers weld lifting points onto each group of cross-shaped impact cone fragments to cut the cross-shaped impact cone and disassemble the entire foreign object into several fragments, reducing the weight of a single lifting operation. Then, construction workers weld lifting points onto the cross-shaped impact cone fragments to facilitate the connection between the cross-shaped impact cone fragments and the lifting hook.

[0035] Step S4: Start the winch to unwind the wire rope. The wire rope, along with the hook, enters the dewatering well. The hook moves above the cross-shaped impact cone fragments. Construction workers connect the hook to the lifting point. Start the winch to wind up the wire rope. The wire rope lifts the cross-shaped impact cone fragments out of the dewatering well via the hook.

[0036] In S3, the cross-shaped impact cone's wing plates need to be cut. The dimensions of the cut cross-shaped impact cone fragments are measured with a tape measure, and the weight of the fragments is weighed using a weighing device. The weight and dimensions of each set of cut cross-shaped impact cone fragments are recorded. Considering the structural characteristics of the cross-shaped impact cone, the wing plates around it are cut first to reduce the weight of a single hoisting. The dimensions of the fragments are measured with a tape measure, and the weight and dimensions of each fragment are recorded to ensure that the fragment specifications meet the hoisting requirements. This effectively solves the problem of the cross-shaped impact cone's excessive weight and difficulty in hoisting it as a whole, reducing the hoisting difficulty and safety risks.

[0037] As shown in Figures 2, 3, and 4, the right cross blade was cut three times, and the size and weight of each cross blade fragment were recorded. Cutting the right cross blade three times further reduced the weight of the fragments. At the same time, the size and weight of the fragments were measured and recorded, which facilitated the rational planning of the hoisting sequence and the load on the hoisting equipment, avoiding hoisting failures caused by inconsistent fragment specifications. The records of the three cuts provided a reference for subsequent operations, ensuring uniform cutting specifications and improving the standardization and consistency of construction.

[0038] In this embodiment, the first piece cut from the right cross blade has dimensions of 350×100×755mm and a weight of 396.375kg; the second piece cut from the right cross blade has dimensions of 334×100×706mm and a weight of 353.706kg; and the third piece cut from the right cross blade has dimensions of 334×100×500mm and a weight of 250.500kg.

[0039] The winch used in this embodiment is a JJK3 model.

[0040] After cutting the right cross flange, steel pipes are immediately used to provide oblique support to the pile head. The steel pipes are at a 60°-65° angle to the horizontal plane, and the upper end of the steel pipes is rigidly connected to the pile head through a collar-type support hoop. When the right cross flange is cut, the pile head loses some of its support force. The steel pipes are used to provide oblique support to the pile head, utilizing the compressive and shear resistance of the steel pipes to provide stable support. The 60°-65° angle between the steel pipes and the horizontal plane maximizes the supporting load-bearing capacity of the steel pipes. At the same time, the upper end of the steel pipes is rigidly connected to the pile head through a collar-type support hoop, enhancing the stability of the support and thus offsetting the stress imbalance of the pile head after cutting. φ48 steel pipes are used.

[0041] The remaining three sets of cross plates were cut using the same cutting method as the right cross plate. After cutting, steel pipes were used to provide oblique support for the pile head. The left cross plate, front cross plate, and rear cross plate were then cut in sequence using the same cutting method as the right cross plate. After each set of cross plates was cut, steel pipes of the same specifications were immediately used to provide oblique support for the pile head to continuously counteract the stress imbalance of the pile head and ensure the stability of the pile head structure throughout the cutting process, facilitating the orderly conduct of subsequent hoisting operations.

[0042] After the cross blade is cut, a chain hoist is used to apply preload to the impact cone to balance its own weight and transfer the force. The original steel pipe support and collar support hoop are removed. After the cross blade is cut, a chain hoist is used to connect it to the impact cone. The chain hoist keeps the impact cone stable. Under balanced force, the original steel pipe support and collar support hoop are removed to avoid the support structure interfering with the subsequent drill bit hoisting.

[0043] By gradually and slowly lowering the impact cone to a horizontal position using a chain hoist, construction workers fully weld steel lifting points at the top of the impact cone. After the impact cone is in a horizontal position, the force on the cone is evenly distributed, facilitating the welding of the lifting points. By utilizing the high-strength connection characteristics of full welding, it is ensured that the lifting points can bear the weight of the cone, preventing safety accidents caused by the lifting points falling off. At the same time, slowly lowering the impact cone using a chain hoist can prevent the cone from colliding with the well wall and damaging the equipment or well structure.

[0044] The winch is started to lower the hook into the dewatering well. The construction workers connect the hook to the lifting point of the impact cone, and the winch is started to wind up the steel wire traction rope. The impact cone is pulled to the wellhead of the dewatering well through the hook along the preset path. The preset path traction can accurately transfer the cone to the wellhead, reduce the deviation during the hoisting process, and improve the hoisting efficiency.

[0045] A gantry crane is used to lower the hook into the dewatering well. Construction workers connect the hook of the gantry crane to the lifting point above the impact cone. The gantry crane is then activated to vertically lift the impact cone through the lifting point, slowly raising and hoisting it out of the working well to the designated area on the ground. The gantry crane is then activated again to vertically lift the impact cone through the lifting point. Utilizing the reasonable force distribution of vertical lifting, the cone is prevented from tilting or colliding. The cone is then slowly raised and hoisted out of the working well to the designated area on the ground, completing the removal of the foreign object.

[0046] The selection and verification of steel rope in this embodiment

[0047] Steel rope selection: According to the principle that "when lifting and hoisting, the safety factor of the steel wire rope should be no less than 6, and the safety factor of the steel wire rope for lifting exceeding a certain scale should be no less than 8; the heaviest component being lifted in this case is about 19.085kN, and considering safety, the safety factor is taken as 8."

[0048] Assuming a steel wire rope with a tensile strength of 1700 N / mm² is selected, according to the formula F=nT×K (F is the tensile force borne by a single steel wire rope, T is the weight of the object being lifted, K is the safety factor, and n is the number of steel wire ropes), if 4 steel wire ropes are used for lifting, then the tensile force borne by a single steel wire rope is F=(19085.22×8) / 4=38170.44N;

[0049] From F = σ × A (where σ is the tensile strength of the wire rope and A is the cross-sectional area of ​​the wire rope), we can obtain A = F / σ = 38170.44 / 1700 = 22.45 mm².

[0050] According to the wire rope specification table, a wire rope with a diameter of 6×37+1 and a diameter d=15mm can be selected (its cross-sectional area can meet the requirements, but the specific requirements need to be determined according to the actual wire rope specification parameters).

[0051] Steel rope calculation: Given the breaking tensile force P of the selected steel wire rope (obtained from the table based on the selected steel wire rope specifications, P=150kN), and the safety factor K=8, then the allowable tensile force of the steel wire rope is... (The tensile force borne by a single wire rope) meets the requirements.

[0052] Selection of lifting lug reinforcement: Considering the weight of the cone head is 1.908t, or 19080N, and based on engineering experience, 18mm diameter steel bars are selected as the lifting lug material. The steel bars have good strength and weldability, meeting general lifting requirements.

[0053] Welding length calculation

[0054] Load calculation: The weight of the cone head is G = 19080N. Considering factors such as the dynamic load factor, assuming the dynamic load factor is K = 1.2, the actual load is N = K × G = 1.2 × 19080 = 22896N.

[0055] Weld strength calculation: The weld leg size hf is determined based on the diameter of the reinforcing bar and the welding process. If the diameter of the reinforcing bar is 18mm, take hf=6mm.

[0056] Strength calculation formula is Where τf is the shear stress of the weld, L is the weld length, and ffw is the design strength value of the weld, which can be taken as 160 N / mm². The strength calculation formula is: where τf is the shear stress of the weld, L is the weld length, and ffw is the design strength value of the weld, which can be taken as 160 N / mm².

[0057] Depend on Substitute, Considering the actual stress conditions, the weld length is taken as L=100mm (double-sided weld).

[0058] Full welding requirements: For full welding, ensure the weld is continuous and full, free from defects such as porosity, slag inclusions, and cracks. During welding, use appropriate welding current, voltage, and speed. For welding reinforcing bars to cones, use E43 welding rods. Before welding, clean the welding area to remove oil, rust, and other impurities. After welding, grind the weld to make its surface smooth.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for cutting and removing foreign objects in front of a shield tunnel, characterized in that, Includes the following steps: Step S1: Construct a hoisting platform next to the dewatering well. Install a hoisting frame on top of the hoisting platform. A winch is bolted to the upper surface of the hoisting frame. A steel wire traction rope is wound on the drum of the winch. A hook is attached to the other end of the steel wire traction rope. Move the hook above the dewatering well. Step S2: Connect the shield tunnel to the dewatering well. Clear the slag and concrete inside the tunnel. Use cutting equipment to cut the cross-shaped impact cone. Step S3: Cut the cross-shaped impact cone into several groups of fragments. Have construction workers weld lifting points onto each group of cross-shaped impact cone fragments. Step S4: Start the winch to unwind the steel wire traction rope. The steel wire traction rope, carrying the hook, enters the dewatering well. Move the hook above the cross-shaped impact cone fragments. Have construction workers connect the hook to the lifting points. Start the winch to wind up the steel wire traction rope. The steel wire traction rope lifts the cross-shaped impact cone fragments through the hook and removes them from the dewatering well.

2. The method for cutting and removing foreign objects in front of a shield tunnel according to claim 1, characterized in that: In S3, the cross blades around the cross-shaped impact cone need to be cut. The size of the cut cross-shaped impact cone fragments is measured with a tape measure, and the weight of the cross-shaped impact cone fragments is weighed with a weighing device. The weight and size of each set of cut cross-shaped impact cone fragments are recorded.

3. The method for cutting and removing foreign objects in front of a shield tunnel according to claim 2, characterized in that: The right crossblade was cut three times, and the size and weight of each crossblade fragment were recorded.

4. The method for cutting and removing foreign objects in front of a shield tunnel according to claim 3, characterized in that: After cutting the right cross flange, immediately use steel pipes to provide oblique support for the pile head. The steel pipes are at an angle of 60°-65° to the horizontal plane, and the upper end of the steel pipes is rigidly connected to the pile head through a collar-type support hoop.

5. The method for cutting and removing foreign objects in front of a shield tunnel according to claim 4, characterized in that: The remaining three sets of cross plates were cut by cutting the right cross plate. After the cutting was completed, steel pipes were used to provide oblique support for the pile head.

6. A method for cutting and removing foreign objects in front of a shield tunnel according to claim 5, characterized in that: After the cross blades are cut, a chain hoist is used to apply preload to the impact drill bit to balance its own weight and transfer the force. The original steel pipe support and the ring-type support hoop are then removed.

7. A method for cutting and removing foreign objects in front of a shield tunnel according to claim 6, characterized in that: By gradually and slowly lowering the impact cone to a horizontal position using a chain hoist, construction workers weld steel lifting points to the top of the impact cone.

8. A method for cutting and removing foreign objects in front of a shield tunnel according to claim 7, characterized in that: The winch is started to lower the hook into the dewatering well. The construction workers connect the hook to the lifting point of the impact cone, start the winch to wind up the steel wire traction rope, and pull the impact cone to the wellhead of the dewatering well through the hook according to the preset path.

9. A method for cutting and removing foreign objects in front of a shield tunnel according to claim 8, characterized in that: A gantry crane is used to lower the hook into the dewatering well. Construction workers connect the hook of the gantry crane to the lifting point above the impact cone, start the gantry crane to lift the impact cone vertically through the lifting point, and slowly lift it out of the working well to the designated area on the ground.

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