A construction method for controlling the risk of pipe jacking machine entering a hole and heading for pipe jacking construction

Abstract

The application provides a construction method for controlling the risk of hole entering and head planting of a pipe jacking machine suitable for pipe jacking construction, steps 1) reinforcing treatment of soil bodies at the starting end and receiving end of the pipe jacking machine construction is performed by using double-pipe rotary jet grouting piles; step 2) the soil bodies in the region to be constructed are detected and classified, and different jacking postures are performed according to the different compressibilities of the soil bodies at the starting end of the pipe jacking machine: the posture of the pipe jacking machine is lifted by 0-1 cm for jacking at the starting end when the compressibility is low; the posture of the pipe jacking machine is lifted by 2-3 cm for jacking at the starting end when the compressibility is medium; and the posture of the pipe jacking machine is lifted by 3-5 cm for jacking at the starting end when the compressibility is high; step 3) the tail of the pipe jacking machine and the front several pipe joints are connected through a lead screw; and step 4) the jacking speed of the pipe jacking machine at the starting section or the receiving section is reduced, and the jacking speed is controlled to be 1 / 5-1 / 3 of the normal jacking speed. The execution of the method can effectively solve the problem of hole entering and head planting in the pipe jacking construction process.

Description

Technical Field

[0001] This invention relates to the field of pipe jacking construction technology, and more specifically, to a construction method applicable to pipe jacking construction that controls the risk of pipe jacking machine head falling during tunnel entry. Background Technology

[0002] Pipe jacking, as a type of underground excavation method, is widely used in the construction of various underground projects because it requires relatively little site area.

[0003] When using the pipe jacking method, the weight of the pipe jacking machine is initially borne by the tunnel portal frame and the starting bracket when it enters and exits the tunnel. After the pipe jacking machine has advanced a certain distance, most of the weight of the machine body will be borne by the soil. Since the soil has a weak bearing capacity, the ground will subside under the action of gravity, causing the front shield of the pipe jacking machine to sink and the tail of the machine to tilt upward, resulting in the phenomenon of head-down.

[0004] Once the pipe jacking machine experiences a head-down phenomenon, it becomes difficult to jack up along the pre-set jacking route.

[0005] In existing technologies, such as CN202210722436.6, "A method to prevent the head from falling during the construction of a slurry pipe jacking machine," it is mentioned that the connection and bracing between the jacking pipe and the pipe section prevent the pipe jacking machine from falling over during long-term operation in soft soil layers.

[0006] However, this method requires a large investment, is difficult to construct, and is not systematic enough, thus failing to fully address the safety issues of pipe jacking construction. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a construction method suitable for pipe jacking construction that controls the risk of pipe jacking machine head falling during tunnel entry, thus solving the problem of head falling.

[0008] To achieve the above objectives, the technical solution adopted by this invention is: a construction method for controlling the risk of pipe jacking machine head collapse during tunnel entry in pipe jacking construction, implemented through the following steps:

[0009] Step 1) Reinforce the soil at the starting and receiving ends of the pipe jacking machine using double-pipe jet grouting piles. The reinforcement length at both the starting and receiving ends shall be greater than or equal to the length L1 of the pipe jacking machine.

[0010] Step 2) The soil in the construction area is tested and classified. Based on the soil compressibility, it is divided into low compressibility, medium compressibility, and high compressibility. The pipe jacking machine adopts different jacking postures at the starting end according to the different soil compressibility:

[0011] When the soil is low compressibility, raise the pipe jacking machine by 0-1cm to start the jacking; when the soil is medium compressibility, raise the pipe jacking machine by 2-3cm to start the jacking; when the soil is high compressibility, raise the pipe jacking machine by 3-5cm to start the jacking.

[0012] Step 3) Connect the tail section of the pipe jacking machine to the first few pipe sections using screws to form a whole, so that the overall center of gravity is shifted backward to balance the weight of the pipe jacking machine head.

[0013] The number of connected pipe sections is determined by the following formula:

[0014] [n] = max(n1, n2)

[0015] Where n1 = L1 / L2, L1 is the length of the pipe jacking machine, and L2 is the length of a single pipe section;

[0016] n2 = G1 / G2, where G1 is the weight of the pipe jacking machine and G2 is the weight of a single pipe section;

[0017] Step 4) Reduce the jacking speed of the pipe jacking machine in the starting or receiving section, and control the jacking speed to 1 / 5 to 1 / 3 of the normal jacking speed.

[0018] Preferably, steel plates are pre-embedded on the inner side of the first few pipe sections connected to the pipe jacking machine, and the pre-embedded steel plates are connected by threaded rods.

[0019] Preferably, the soil compressibility is evaluated using the compressibility coefficient α1-2 corresponding to a pressure range of 100–200 kPa, i.e.:

[0020] Soils with a1-2 < 0.1 MPa are classified as low compressibility soils; soils with a1-2 ≤ 0.1 MPa < 0.5 MPa are classified as medium compressibility soils; and soils with a1-2 ≥ 0.5 MPa are classified as high compressibility soils.

[0021] Preferably, in step 3), the remaining pipe sections are connected by threaded rods.

[0022] Preferably, the pipe jacking machine is 6m long and weighs 180t.

[0023] Preferably, the length of a single pipe section is 1.5m and the weight is 63.1t.

[0024] Preferably, the tail section of the pipe jacking machine is connected to the first four pipe sections via screw rods.

[0025] This invention has significant substantive features and remarkable progress compared to existing technologies. Specifically, this invention reinforces the soil at both the starting and receiving ends, effectively improving the soil's bearing capacity and giving the pipe jacking machine high stability in the prone-to-heading areas at both ends. After passing through the reinforced area, the pipe jacking machine can move forward stably due to the fixed connection between the machine and the preceding pipe sections, reducing the occurrence of head-down phenomena. With the aid of this inertia, the length of the stable stroke is extended. Based on this structural characteristic, the jacking posture can be adjusted according to the different compressibility of the soil. With a lower elevation distance, the pipe jacking machine can continue to jack along the predetermined jacking route after settlement, ensuring the normal progress of the jacking work.

[0026] In addition, the tail section of the pipe jacking machine and the first few pipe sections are connected by screw rods to form a whole, which shifts the center of gravity of the pipe jacking machine to the rear. Combined with the processes in steps 1) and 2), this can effectively reduce the phenomenon of the pipe jacking machine head falling. The inner side of the first four pipe sections is pre-embedded with steel plates, and the pre-embedded steel plates are connected by screw rods, which can effectively enhance its integrity.

[0027] Finally, during the jacking process, reduce the jacking speed of the pipe jacking machine at the starting and receiving ends. The speed should be 1 / 5 to 1 / 3 of the normal jacking speed to reduce the impact on the soil. The attitude of the pipe jacking machine can also be adjusted in a timely manner according to the progress of the pipe jacking machine in the tunnel. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the reinforcement at the transmitting and receiving ends of the present invention.

[0029] Figure 2 This is a schematic diagram of the elevation of the pipe jacking machine according to the present invention.

[0030] Figure 3 This is a schematic diagram of the pipe jacking machine and pipe section connected by a screw rod according to the present invention.

[0031] 1. Reinforced area; 2. Pipe jacking area; 3. Soil outside the pipe jacking area; 4. Pipe jacking machine; 5. Pipe jacking machine starting base; 6. Pipe section; 7. Screw rod. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0033] like Figure 1 As shown, a construction method for controlling the risk of pipe jacking machine head collapse during tunneling, applicable to pipe jacking construction, is implemented through the following steps:

[0034] Step 1) Reinforce the soil at both the starting and receiving ends of the pipe jacking machine 4 using double-tube jet grouting piles, such as... Figure 1In the reinforcement area 1 shown, the reinforcement length at both the starting end and the receiving end is greater than or equal to the length L1 of the pipe jacking machine. In this embodiment, the pipe jacking machine is 6m long and weighs 180t, so the reinforcement length is also 6m. Figure 1 In the diagram, the pipe jacking area 2 and the soil outside the pipe jacking area 3 show the overall operation of the pipe jacking machine 4.

[0035] Step 2) The soil in the construction area is tested and classified. Based on the soil compressibility, the soil is divided into low compressibility, medium compressibility, and high compressibility. The soil compressibility is evaluated using the compressibility coefficient α1-2 corresponding to the pressure range of 100-200 kPa, i.e.:

[0036] Soils with a1-2 < 0.1 MPa are classified as low compressibility soils; soils with a1-2 ≤ 0.1 MPa < 0.5 MPa are classified as medium compressibility soils; and soils with a1-2 ≥ 0.5 MPa are classified as high compressibility soils.

[0037] The pipe jacking machine employs different jacking postures at the starting end depending on the soil compressibility:

[0038] When the soil is low compressibility, raise the pipe jacking machine by 0-1cm to start the jacking; when the soil is medium compressibility, raise the pipe jacking machine by 2-3cm to start the jacking; when the soil is high compressibility, raise the pipe jacking machine by 3-5cm to start the jacking.

[0039] like Figure 2 As shown, x cm represents the height (in cm) that the pipe jacking machine 4 is raised relative to the starting base 5 of the pipe jacking machine.

[0040] Step 3) as Figure 3 As shown, the tail section of the pipe jacking machine 4 and the first few pipe sections 6 are connected by screws 7 to form a whole, so that the center of gravity of the whole is shifted backward to balance the weight of the pipe jacking machine head.

[0041] The number of connected pipe sections is determined by the following formula:

[0042] [n] = max(n1, n2)

[0043] Where n1 = L1 / L2, L1 is the length of the pipe jacking machine, and L2 is the length of a single pipe section;

[0044] n2 = G1 / G2, where G1 is the weight of the pipe jacking machine and G2 is the weight of a single pipe section;

[0045] In this embodiment, the length of a single pipe section is 1.5m and the weight is 63.1t. Calculations show that the shield tail 4 of the pipe jacking machine can be connected to the first four pipe sections 6 via threaded rods. Steel plates are pre-embedded on the inner side of the first few pipe sections connected to the pipe jacking machine, and these pre-embedded steel plates are connected to each other via threaded rods. The remaining pipe sections are then connected to each other via threaded rods.

[0046] Step 4) Reduce the jacking speed of the pipe jacking machine in the starting or receiving section, and control the jacking speed to 1 / 5 to 1 / 3 of the normal jacking speed.

[0047] After setting the operating parameters of the pipe jacking machine according to the above parameters, the pipe jacking machine can be controlled to move along the predetermined route, starting from the starting end and ending at the receiving end.

[0048] Finally, it should be noted that: the preferred embodiments of this patent have been described in detail above, but this patent is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this patent.

Claims

1. A construction method for controlling the risk of pipe jacking machine head collapse during tunneling, applicable to pipe jacking construction, characterized in that: This will be implemented through the following steps: Step 1) Reinforce the soil at the starting and receiving ends of the pipe jacking machine using double-pipe jet grouting piles. The reinforcement length at both the starting and receiving ends shall be greater than or equal to the length L1 of the pipe jacking machine. Step 2) The soil in the construction area is tested and classified. Based on the soil compressibility, it is divided into low compressibility, medium compressibility, and high compressibility. The pipe jacking machine adopts different jacking postures at the starting end according to the different soil compressibility: When the soil is low compressibility, raise the pipe jacking machine by 0-1cm to start the jacking; when the soil is medium compressibility, raise the pipe jacking machine by 2-3cm to start the jacking; when the soil is high compressibility, raise the pipe jacking machine by 3-5cm to start the jacking. Step 3) Connect the tail section of the pipe jacking machine to the first few pipe sections using screws to form a whole, so that the overall center of gravity is shifted backward to balance the weight of the pipe jacking machine head. The number of connected pipe sections is determined by the following formula: [n] = max(n1, n2) Where n1 = L1 / L2, L1 is the length of the pipe jacking machine, and L2 is the length of a single pipe section; n2 = G1 / G2, where G1 is the weight of the pipe jacking machine and G2 is the weight of a single pipe section; Step 4) Reduce the jacking speed of the pipe jacking machine in the starting or receiving section, and control the jacking speed to 1 / 5 to 1 / 3 of the normal jacking speed.

2. The construction method for controlling the risk of pipe jacking machine head collapse during tunneling, applicable to pipe jacking construction according to claim 1, is characterized in that: The first few pipe sections connected to the pipe jacking machine have steel plates pre-embedded on their inner sides, and the pre-embedded steel plates are connected to each other by threaded rods.

3. The construction method for controlling the risk of pipe jacking machine head collapse during tunnel entry in pipe jacking construction according to claim 2, characterized in that: The soil compressibility is evaluated using the compressibility coefficient α1-2 corresponding to a pressure range of 100–200 kPa, i.e.: Soils with a1-2 < 0.1 MPa are classified as low compressibility soils; soils with a1-2 ≤ 0.1 MPa < 0.5 MPa are classified as medium compressibility soils; and soils with a1-2 ≥ 0.5 MPa are classified as high compressibility soils.

4. The construction method for controlling the risk of pipe jacking machine head collapse during tunneling, applicable to pipe jacking construction according to claim 3, is characterized in that: In step 3), the remaining pipe sections are connected by threaded rods.

5. The construction method for controlling the risk of pipe jacking machine head collapse during tunneling, applicable to pipe jacking construction according to claim 4, is characterized in that: The pipe jacking machine is 6m long and weighs 180t.

6. The construction method for controlling the risk of pipe jacking machine head collapse during tunnel entry in pipe jacking construction according to claim 5, characterized in that: Each pipe section is 1.5m long and weighs 63.1t.

7. The construction method for controlling the risk of pipe jacking machine head collapse during tunneling, applicable to pipe jacking construction according to claim 6, is characterized in that: The tail section of the pipe jacking machine is connected to the first four pipe sections via threaded rods.

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