Shield tunnel construction method based on heat source to enhance stability of soft soil layer

Abstract

This invention proposes a shield tunnel construction method based on heat source enhancement of the stability of weak soil layers, comprising the following steps: S1, determining the range of the weak soil layer requiring reinforcement, and deploying drilling equipment above the weak soil layer to drill holes in the weak soil layer; S2, assembling a heating and drying device, placing the heating and drying device into the drill hole, and operating the fan and heating device. The fan blows air into the drill hole through a connecting pipe to dry the surface of the drill hole, while the heating device heats the weak soil layer around the drill hole, raising its temperature until a reinforced area is formed; S3, after the weak soil layer reinforcement is completed, the heating and drying device is removed from the drill hole, and the shield machine tunnels through the reinforced soil layer to carry out tunnel construction. This invention can effectively enhance the stability of weak soil layers, pre-control the instability and deformation of weak soil layers caused by shield tunnel construction, and provide a guarantee for the safety of underground engineering construction in relevant weak soil layers.

Description

Technical Field

[0001] This invention relates to the field of underground engineering technology, specifically to a shield tunnel construction method based on heat source to enhance the stability of soft soil layers. Background Technology

[0002] Coastal cities in my country are widely covered with soft soils of varying depths and thicknesses, including saturated clay, silty clay, and silty clay (thickness ranging from 3 to 30 meters, burial depth from 2 to 20 meters). These soils are characterized by high compressibility, low shear strength, and high sensitivity. Constructing underground rail transit projects in such geological areas can easily lead to large-scale landslides and deformation of the surrounding rock, endangering the lives of construction workers and causing significant economic losses to the city. Therefore, effectively controlling the deformation and damage of soft soil layers under tunnel construction disturbances is of significant theoretical importance and guiding significance for the design and construction of tunnels in soft soil layers. To this end, a shield tunneling method based on heat source enhancement to improve the stability of soft soil layers was developed, providing technical assurance for the safety of shield tunneling in soft soil layers. Summary of the Invention

[0003] To address the problems existing in the background technology, effectively enhance the stability of weak soil layers, and effectively pre-control the instability and deformation of weak soil layers caused by shield tunnel construction, this invention proposes a shield tunnel construction method based on heat source to enhance the stability of weak soil layers. The method includes construction equipment, which comprises drilling equipment, a heating and drying device, and a shield machine. The shield machine has a cutterhead at its front end, and a wear-resistant dust suppressant is placed in front of the cutterhead. The heating and drying device comprises multiple heating sections, each with a connecting pipe. The multiple heating sections are connected sequentially, and the connecting pipes are interconnected. A fan is connected to the connecting pipe at the top of the heating and drying device. Both the fan and the heating devices are connected to an electrical energy source. The construction method includes the following steps: S1. Determine the range of the weak soil layer that needs to be reinforced, set up drilling equipment above the weak soil layer, and use the drilling equipment to drill holes in the weak soil layer. S2. Assemble the heating and drying device, place the heating and drying device into the borehole, and operate the fan and heating device. The fan blows air into the borehole through the connecting pipe to dry the surface of the borehole. The heating device heats the borehole, raising the temperature of the soft soil layer around the borehole until a reinforced area is formed. S3. After the weak soil layer is reinforced, the heating and drying device is removed from the borehole, and the tunnel boring machine tunnels through the reinforced soil layer to carry out tunnel construction.

[0004] Preferably, the heating device includes a cylindrical iron-containing container and an electromagnetic coil. The iron-containing container has a hollow structure, and the electromagnetic coil is disposed inside the hollow of the iron-containing container. The electromagnetic coil is connected to an electrical energy device, and the connecting pipe is inserted into the iron-containing container.

[0005] Preferably, the multiple iron-containing containers are divided into a top iron-containing container, a bottom iron-containing container, and multiple middle iron-containing containers. The bottom of the top iron-containing container and the middle iron-containing containers are provided with insertion ports, and the top of the bottom iron-containing container and the middle iron-containing containers are provided with insertion heads. The insertion heads and insertion ports are connected to the electromagnetic coils in the iron-containing containers they are in. The insertion heads and insertion ports of two adjacent iron-containing containers in the heating and drying device are inserted and matched.

[0006] Preferably, the connecting pipe inserted into the iron-containing container at the top is a top connecting pipe, the connecting pipe inserted into the iron-containing container at the bottom is a bottom connecting pipe, and the connecting pipe inserted into the iron-containing container in the middle is a middle connecting pipe. The inner walls of the bottom connecting pipe and the middle connecting pipe are both provided with internal threads, and the outer walls of the bottom of the top connecting pipe and the middle connecting pipe are both provided with external threads. The stroke length of the external threads is the same as that of the internal threads. The bottom connecting pipe is fixedly connected to the bottom iron-containing container, the top iron-containing container and the top connecting pipe are slidably connected, the length of the top connecting pipe is greater than the length of the top iron-containing container, and the length of the top connecting pipe greater than the length of the top iron-containing container is the stroke length of the external thread; the middle iron-containing container and the middle connecting pipe are slidably connected, the length of the middle connecting pipe is greater than the length of the middle iron-containing container, and the length of the middle connecting pipe greater than the length of the middle iron-containing container is the stroke length of the external thread; The top outer walls of both the top connecting pipe and the middle connecting pipe are fixedly provided with baffles, and the top of both the iron-containing container at the top and the iron-containing container in the middle are provided with baffle grooves that match the shape and position of the baffles. In the heating and drying device, two adjacent connecting pipes are connected by a mating external thread and an internal thread, and after the connecting pipes are connected, the baffle is located in the baffle groove.

[0007] Preferably, there are two insertion ends, which are symmetrically located on both sides of the inner hole of the iron-containing container and are located in the same radial direction on the iron-containing container. The number and position of the insertion ports correspond to the number of insertion ends.

[0008] Preferably, the drilling layout is a plum blossom pattern, with a spacing of 30-50cm between adjacent drilling holes and a hole diameter of 100-120mm.

[0009] Preferably, the drilling equipment is a down-the-hole drill, and the drilling equipment uses a rotary or impact method during drilling.

[0010] The beneficial effects of this invention are as follows: 1. This invention can effectively enhance the stability of weak soil layers, realize the reinforcement of weak soil layers, and provide safety assurance for underground engineering construction.

[0011] 2. This invention can effectively prevent and control the instability and deformation of soft soil layers caused by shield tunnel construction, ensuring tunnel construction safety and surrounding rock stability. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the drilling state during the present invention; Figure 2 This is a schematic diagram of the borehole distribution state of the present invention; Figure 3 This is a schematic diagram of the heating and drying device of the present invention. Figure 4 This is a cross-sectional view of the top-heated air-drying device of the present invention; Figure 5 This is a cross-sectional view of the intermediate heating and drying device of the present invention; Figure 6 This is a cross-sectional view of the bottom heating and drying device of the present invention; Figure 7 This is a top view of the heating and drying device of the present invention; Figure 8 This is a schematic diagram of the working state when the present invention reinforces a weak soil layer; Figure 9 This is a side view of the cutter head structure of the present invention; Figure 10 This is a front view of the cutter head structure of the present invention.

[0013] Numbered in the diagram: 1. Soft soil layer; 2. Drilling equipment; 3. Drill hole; 4. Power energy device; 5. Cable; 6. Connecting pipe; 61. Top connecting pipe; 62. Middle connecting pipe; 63. Bottom connecting pipe; 64. External thread; 65. Internal thread; 7. Baffle; 8. Heating device; 81. Iron-containing container at the top; 82. Iron-containing container in the middle; 83. Iron-containing container at the bottom; 84. Electromagnetic coil; 9. Insertion end; 10. Insertion port; 11. Tunnel boring machine; 12. Reinforcement area; 13. Wear-resistant dust suppressant; 14. Cutterhead; 15. Fan. Detailed Implementation

[0014] To make the present invention clearer and more understandable, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the given embodiments are only one implementation method and do not represent all embodiments.

[0015] In this article, terms such as "upper," "lower," "inner," and "outer" are established based on the positional relationships shown in the attached drawings. Depending on the attached drawings, the corresponding positional relationships may also change. Therefore, they should not be interpreted as an absolute limitation on the scope of protection.

[0016] Combined with appendix Figure 1-10 This invention proposes a shield tunnel construction method based on heat source to enhance the stability of soft soil layer 1. The method includes construction equipment, which includes drilling equipment 2, heating and drying device and shield machine 11. The shield machine 11 is equipped with a cutterhead 14 at the front end. A large amount of wear-resistant dust suppressant 13 is provided in front of the cutterhead 14. The wear-resistant dust suppressant 13 protects the cutter head 14 and reduces dust. The shield tunneling machine 11 is a construction equipment commonly used in subway tunnel construction. Generally, an earth pressure balance shield tunneling machine is selected in soft soil layer 1. The heating and drying device includes multiple heating devices 8, each of which is equipped with a connecting pipe 6. After the multiple heating devices 8 are connected in sequence, the multiple connecting pipes 6 are connected. The connecting pipe 6 at the top of the heating and drying device is connected to a fan 15. The opening of the connecting pipe 6 at the bottom of the heating and drying device is the air outlet. During air drying, the fan 15 blows air into the connecting pipe 6, and the air is blown out from the air outlet. After the heating and drying device is inserted into the borehole 3, the air will flow from the bottom of the borehole 3 to the top of the borehole 3 to achieve air drying of the inner wall of the borehole 3. The fan 15 and the heating device 8 are both connected to an electric power device 4, which supplies power to the fan 15 and the heating device 8. The electric power device 4 is an electrical device that can provide energy, such as a generator or battery. Specifically, the electric power device 4 is connected to the electromagnetic coil 84 and the fan 15 through a cable 5. The construction method includes the following steps: S1. Determine the range of the weak soil layer 1 that needs to be reinforced, install drilling equipment 2 above the weak soil layer 1, and use drilling equipment 2 to drill holes in the weak soil layer 1. S2. Assemble the heating and drying device and place it into the borehole 3. The fan 15 and the heating device 8 work. The fan 15 blows air into the borehole 3 through the connecting pipe 6 to dry the surface of the borehole 3. The heating device 8 heats the borehole 3, raising the temperature of the soft soil layer 1 around the borehole 3 until the reinforcement area 12 is formed. Drying and heating can be carried out simultaneously. Since the moisture in the soft soil layer 1 may evaporate during the heating process, the air blown out by the connecting pipe 6 can carry away the moisture generated during the heating process, avoiding secondary wetting of the soil layer by moisture, which would affect the reinforcement effect of the soil layer. After the reinforcement of the weak soil layer 1 is completed, the heating and drying device is removed from the borehole 3, and the tunnel boring machine 11 tunnels through the reinforced soil layer to carry out tunnel construction.

[0017] Specifically, the heating device 8 includes a cylindrical iron-containing container and an electromagnetic coil 84. The iron-containing container has a hollow structure, and the electromagnetic coil 84 is placed inside the hollow of the iron-containing container. The electromagnetic coil 84 is connected to the power energy device 4. When the electromagnetic coil 84 is energized, it generates heat energy, and the iron-containing container rapidly heats up (the heating temperature is 600℃-900℃) and conducts heat, continuously transferring heat to the soft soil layer 1 around the borehole 3. Under the action of temperature, the soft soil produces a temperature effect, that is, the water content inside the soft soil rapidly decreases, its compressive strength increases, and its stability is enhanced; the connecting pipe 6 is inserted into the iron-containing container.

[0018] Specifically, the multiple iron-containing containers are divided into a top iron-containing container 81, a bottom iron-containing container 83, and multiple middle iron-containing containers 82. The bottom of the top iron-containing container 81 and the middle iron-containing container 82 are provided with an insertion port 10, and the top of the bottom iron-containing container 83 and the middle iron-containing container 82 are provided with an insertion end 9. The insertion end 9 and the insertion port 10 are connected to the electromagnetic coil 84 in the iron-containing container they are in. The insertion end 9 and the insertion port 10 of two adjacent iron-containing containers in the heating and drying device are plugged in and matched. The insertion end 9 and the insertion port 10 are copper wire connectors and copper wire interfaces, respectively, used to connect the electromagnetic coils 84 in the two adjacent iron-containing containers.

[0019] Specifically, the connecting pipe 6 inserted into the iron-containing container 81 at the top is the top connecting pipe 61, the connecting pipe 6 inserted into the iron-containing container 83 at the bottom is the bottom connecting pipe 63, and the connecting pipe 6 inserted into the iron-containing container 82 in the middle is the middle connecting pipe 62. The inner walls of the top ends of the bottom connecting pipe 63 and the middle connecting pipe 62 are provided with internal threads 65, and the outer walls of the bottom ends of the top connecting pipe 61 and the middle connecting pipe 62 are provided with external threads 64. The external threads 64 and the internal threads 65 have the same stroke length. The bottom connecting pipe 63 is fixedly connected to the bottom iron-containing container 83. The top iron-containing container 81 and the top connecting pipe 61 are slidably connected. The length of the top connecting pipe 61 is greater than the length of the top iron-containing container 81. The length of the top connecting pipe 61 greater than the length of the top iron-containing container 81 is the stroke length of the external thread 64. The middle iron-containing container 82 and the middle connecting pipe 62 are slidably connected. The length of the middle connecting pipe 62 is greater than the length of the middle iron-containing container 82. The length of the middle connecting pipe 62 greater than the length of the middle iron-containing container 82 is the stroke length of the external thread 64. The top outer walls of the top connecting pipe 61 and the middle connecting pipe 62 are both fixedly provided with baffles 7, and the top iron-containing container 81 and the middle iron-containing container 82 are both provided with baffle 7 grooves that match the shape and position of the baffles 7. In the heating and drying device, two adjacent connecting pipes 6 are connected by the mating threads of external thread 64 and internal thread 65, and the baffle 7 is located in the groove of the baffle 7 after the connecting pipes 6 are connected.

[0020] Specifically, step S2 involves inserting the insertion end 9 at the top of the bottom iron-containing container 83 into the insertion port 10 at the bottom of the middle iron-containing container 82. At this time, the top of the middle connecting pipe 62 in the middle iron-containing container 82 extends out of the middle iron-containing container 82. Tightening the middle connecting pipe 62, the middle connecting pipe 62 is fixedly connected to the bottom connecting pipe 63 through the cooperation of the internal thread 65 and the external thread 64. After the middle connecting pipe 62 is fixedly connected to the bottom connecting pipe 63, the baffle 7 at the top of the middle connecting pipe 62 is located in the groove of the baffle 7 at the top of the middle iron-containing container 82. The baffle 7 can axially limit the middle iron-containing container 82, so that the middle iron-containing container 82 is fixed between the baffle 7 and the bottom iron-containing container 83. Similarly, multiple sections of the middle iron-containing container 82 are connected in accordance with the above principle, and the top iron-containing container 81 is installed in the last section to complete the assembly of the heating and drying device. The prefabricated structure of the heating and drying device can meet the requirements of different drilling depths. After use, it can be disassembled section by section and recycled for reuse, which improves the flexibility of construction. In addition, if the heating and drying device is too long, it will be inconvenient to store and transport. The prefabricated structure can improve the convenience of storage and transportation.

[0021] Specifically, there are two insertion ends 9, which are symmetrically located on both sides of the inner hole of the iron-containing container and are located in the same radial direction on the iron-containing container. The number and position of the insertion ports 10 correspond to the number and position of the insertion ends 9.

[0022] Specifically, the boreholes 3 are arranged in a plum blossom pile pattern, the distance between two adjacent boreholes 3 is 30-50cm, the diameter of the boreholes 3 is 100-120mm, the position and elevation deviation of the boreholes 3 is no more than 10cm, and the depth of the boreholes 3 is determined by the reinforcement depth of the weak soil layer 1.

[0023] Specifically, the drilling equipment 2 is a down-the-hole drill, and the drilling equipment 2 uses a rotary method or an impact method when drilling.

[0024] The above embodiments merely illustrate the basic principles and characteristics of the present invention, but are not limited to these embodiments. It should be understood that those skilled in the art can make various changes and modifications to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A shield tunnel construction method based on heat source to enhance the stability of soft soil layers, characterized in that: The construction equipment includes drilling equipment (2), a heating and drying device and a tunnel boring machine (11). The tunnel boring machine (11) has a cutterhead (14) at the front end and a wear-resistant dust suppressant (13) in front of the cutterhead (14). The heating and drying device includes multiple heating devices (8). Each heating device (8) has a connecting pipe (6). After the multiple heating devices (8) are connected in sequence, the multiple connecting pipes (6) are connected. The connecting pipe (6) at the top of the heating and drying device is connected to a fan (15). The fan (15) and the heating device (8) are both connected to an electric power source (4). The construction method includes the following steps: S1, determine the range of the weak soil layer (1) that needs to be reinforced. S2. Drilling equipment (2) is installed above the weak soil layer (1), and the drilling equipment (2) is used to drill holes (3) in the weak soil layer (1); S2. Assemble the heating and drying device, put the heating and drying device into the hole (3), and the fan (15) and heating device (8) work. The fan (15) blows air into the hole (3) through the connecting pipe (6) to dry the surface of the hole (3). The heating device (8) heats the hole (3) to raise the temperature of the weak soil layer (1) around the hole (3) until a reinforced area (12) is formed; S3. After the weak soil layer (1) is reinforced, the heating and drying device is taken out from the hole (3), and the shield machine (11) tunnels through the reinforced soil layer to carry out tunnel construction; The heating device (8) includes a cylindrical iron-containing container and an electromagnetic coil (84). The iron-containing container has a hollow structure. The electromagnetic coil (84) is set inside the hollow of the iron-containing container. The electromagnetic coil (84) is connected to the power energy device (4). The connecting pipe (6) is inserted into the iron-containing container. The multi-section iron-containing container is divided into a top iron-containing container (81), a bottom iron-containing container (83), and a multi-section middle iron-containing container (82). The bottom of the top iron-containing container (81) and the middle iron-containing container (82) are provided with an insertion port (10). The top of the bottom iron-containing container (83) and the middle iron-containing container (82) are provided with an insertion end (9). The insertion end (9) and the insertion port (10) are connected to the electromagnetic coil (84) in the iron-containing container. The insertion end (9) and the insertion port (10) of two adjacent iron-containing containers in the heating and drying device are inserted and matched. The connecting pipe (6) inserted into the iron-containing container (81) at the top is the top connecting pipe (61), the connecting pipe (6) inserted into the iron-containing container (83) at the bottom is the bottom connecting pipe (63), and the connecting pipe (6) inserted into the iron-containing container (82) at the middle is the middle connecting pipe (62); the inner walls of the top ends of the bottom connecting pipe (63) and the middle connecting pipe (62) are provided with internal threads (65), and the outer walls of the bottom ends of the top connecting pipe (61) and the middle connecting pipe (62) are provided with external threads (64), the external threads (64) and the internal threads (65) have the same stroke length; the bottom connecting pipe (63) is fixedly connected to the iron-containing container (83), the iron-containing container (81) at the top and the top connecting pipe (61) are slidably connected, and the length of the top connecting pipe (61) is greater than the length of the iron-containing container (81). The length of the top connecting pipe (61) is longer than the length of the top iron-containing container (81), which is the stroke length of the external thread (64). The middle iron-containing container (82) and the middle connecting pipe (62) are slidably connected. The length of the middle connecting pipe (62) is greater than the length of the middle iron-containing container (82). The length of the middle connecting pipe (62) is greater than the length of the middle iron-containing container (82), which is the stroke length of the external thread (64). The top outer wall of the top connecting pipe (61) and the middle connecting pipe (62) are both fixedly provided with baffles (7). The top of the top iron-containing container (81) and the middle iron-containing container (82) are both provided with baffle grooves that match the shape and position of the baffles (7). In the heating and drying device, two adjacent connecting pipes (6) are connected by the mating threads of the external thread (64) and the internal thread (65). After the connecting pipes (6) are connected, the baffles (7) are located in the baffle groove.

2. The shield tunnel construction method based on heat source to enhance the stability of weak soil layers according to claim 1, characterized in that: There are two insertion ends (9), which are symmetrically located on both sides of the inner hole of the iron-containing container and are located in the same radial direction on the iron-containing container. The number and position of the insertion ports (10) correspond to the number and position of the insertion ends (9).

3. The shield tunnel construction method based on heat source to enhance the stability of weak soil layers according to claim 1, characterized in that: The drill holes (3) are arranged in a plum blossom pattern, with a spacing of 30-50cm between two adjacent drill holes (3) and a diameter of 100-120mm.

4. The shield tunnel construction method based on heat source to enhance the stability of weak soil layers according to claim 1, characterized in that: The drilling equipment (2) is a down-the-hole drill, and the drilling equipment (2) uses a rotary method or an impact method when drilling.

Images