Shield construction method for soft soil stratum, slurry supply system and shield tunneling machine

Abstract

The invention discloses a shield construction method for a soft soil stratum, a mud supply system and a shield tunneling machine, and relates to the technical field of tunnel construction.The shield construction method for the soft soil stratum comprises the steps that a mud pit is excavated beside a shield construction area; adding water and bentonite into the mud pool according to a preset proportion to prepare bentonite slurry, and fermenting the bentonite slurry until the viscosity of the bentonite slurry is greater than preset viscosity; the bentonite slurry in the slurry pool is pumped to a shield tunneling machine; the shield tunneling machine excavates a geologic body according to preset parameters, and the bentonite slurry is sprayed to an excavation face through the shield tunneling machine; wherein the preset parameters comprise the cutter rotating speed, the propelling speed, the thrust and the control torque. By means of the method, instability of the soft soil stratum in the shield construction process on the soft soil stratum can be effectively avoided, and therefore the quality and safety of shield construction are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and particularly relates to a shield construction method, a slurry supply system and a shield machine for soft soil strata. Background Art

[0002] During the shield construction process in soft soil strata, the shield machine slowly advances and gradually penetrates into the soft soil strata for fine excavation of the geological body. When the cutter head of the shield machine cuts and removes the soil, at the moment of excavation, the earth pressure that was originally kept stable by the surrounding soil is rapidly released. This sudden change in pressure causes the original mechanical balance of the soft soil strata to be broken, thereby triggering the instability of the soft soil strata. Specifically, it is manifested as the loosening and deformation of the stratum structure, accompanied by a large amount of sand gushing and water gushing. These phenomena not only seriously interfere with the normal progress of shield construction, reduce the quality of shield construction, but also the sand gushing and water gushing may cause the ground collapse around the construction area, posing a large potential safety hazard and poor safety. Summary of the Invention

[0003] The main object of the present invention is to propose a shield construction method, a slurry supply system and a shield machine for soft soil strata, aiming to solve the technical problems that the instability of the soft soil strata is easily caused during the shield construction process in soft soil strata, resulting in low quality of shield construction and poor safety.

[0004] To achieve the above object, the shield construction method for soft soil strata proposed by the present invention includes:

[0005] Excavate a slurry pit beside the shield construction area;

[0006] Add water and bentonite into the slurry pit according to a preset ratio to prepare bentonite slurry;

[0007] Ferment the bentonite slurry until the viscosity of the bentonite slurry is greater than the preset viscosity;

[0008] Pump the bentonite slurry in the slurry pit to the shield machine;

[0009] The shield machine excavates the geological body according to preset parameters, and sprays the bentonite slurry onto the excavation surface through the shield machine; wherein, the preset parameters include cutter head rotation speed, propulsion speed, thrust, control torque, the cutter head rotation speed is 1.5 r / min to 2 r / min, the propulsion speed is 1 mm / min, the thrust is less than 4000 KN, and the control torque is less than 400 kN·m.

[0010] In an embodiment, the shield construction method is used to excavate the geological body from the starting section to the receiving section;

[0011] The step of adding water and bentonite into the slurry pit according to a preset ratio to prepare bentonite slurry includes:

[0012] When excavating the launching section or the receiving section, add water and bentonite into the slurry pit according to a first ratio to prepare the bentonite slurry; wherein, the first ratio is that water and bentonite are mixed in a ratio of 4:1.

[0013] In one embodiment, the step of adding water and bentonite into the slurry pit according to a preset ratio to prepare bentonite slurry further includes:

[0014] When excavating the position between the launching section and the receiving section, add water and bentonite into the slurry pit according to a second ratio to prepare the bentonite slurry; wherein, the second ratio is that water and bentonite are mixed in a ratio of 6:1.

[0015] In one embodiment, the bentonite is sodium-based bentonite.

[0016] In one embodiment, the preset viscosity is 60 mPa·s.

[0017] The present invention also provides a slurry supply system, which is applied to the shield construction method for soft soil strata described above, and the slurry supply system includes a slurry pit.

[0018] In one embodiment, the slurry supply system further includes a conveying pipeline, a water supply device and a bentonite supply device. The water supply device is used to supply water to the slurry pit, the bentonite supply device is used to supply bentonite to the slurry pit, and the conveying pipeline is used to pump the bentonite slurry in the slurry pit to the shield machine.

[0019] In one embodiment, the water supply device includes a water delivery pipe for inputting water into the slurry pit. The bentonite supply device includes a storage bin and a conveyor belt. The storage bin is used to store the bentonite, and the conveyor belt is used to transport the bentonite to the slurry pit.

[0020] In one embodiment, the slurry supply system further includes a controller. The water delivery pipe is provided with a proportional valve. The controller is used to control the proportional valve to control the flow rate of water input into the slurry pit by the water delivery pipe, and the controller is also used to control the conveying speed of the conveyor belt.

[0021] The present invention also provides a shield machine. The shield construction method for soft soil strata described above is applied to the shield machine. The shield machine includes a plurality of injectors arranged at intervals, and the injectors are used to inject bentonite slurry onto the excavation face.

[0022] The technical solution of the present invention can effectively fill the gaps between soil particles and form a dense mud film by preparing bentonite slurry in a mud pit and spraying it on the excavation surface during the excavation process. This mud film can significantly reduce the permeability coefficient of the geological body, thereby improving the impermeability and bearing capacity of the geological body, effectively inhibiting the instability of the soft soil layer, reducing the occurrence of sand gushing and water gushing phenomena, ensuring the stability and safety of the construction area, and ensuring the quality of shield tunneling construction. By spraying bentonite slurry on the excavation surface, the geological body can also have a lower internal friction angle, thereby reducing the cutter head torque and effectively reducing the wear of the cutter head. Controlling the cutter head rotation speed of the shield machine at 1.5 r / min to 2 r / min, setting the propulsion speed at 1 mm / min, making the thrust less than 4000 KN, and making the control torque less than 400 kN·m can enable the shield machine to excavate the soft soil layer more smoothly, thereby effectively avoiding the instability of the soft soil layer. The shield tunneling construction method for soft soil layers provided by the present invention can effectively avoid the instability of the soft soil layer during the shield tunneling construction process in the soft soil layer, thereby improving the quality and safety of the shield tunneling construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0024] Figure 1 It is a schematic flow chart of an embodiment of the shield tunneling construction method for soft soil layers provided by the present invention;

[0025] Figure 2 For Figure 1 a detailed flow chart of step S200 in

[0026] The realization of the purpose, functional characteristics and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0029] In addition, if there are descriptions such as "first", "second", etc. involved in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, or solution B, or the solution where A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0030] During the shield tunneling construction process in soft soil strata, the shield machine slowly advances and gradually penetrates into the soft soil strata for fine excavation of geological bodies. When the cutterhead of the shield machine cuts and removes the soil, at the moment of excavation of the geological body, the earth pressure that was originally kept stable by the surrounding soil is quickly released. This sudden change in pressure causes the original mechanical balance of the soft soil strata to be broken, thereby triggering the instability phenomenon of the soft soil strata. The specific manifestations are the loosening and deformation of the stratum structure, accompanied by the appearance of a large amount of sand gushing and water gushing. These phenomena not only seriously interfere with the normal progress of shield tunneling construction and reduce the quality of shield tunneling construction, but also the sand gushing and water gushing may cause the collapse of the ground around the construction area, with relatively large potential safety hazards and poor safety.

[0031] The present invention provides a shield tunneling construction method, a slurry supply system and a shield machine for soft soil strata.

[0032] Please refer to Figure 1 , in an embodiment of the present invention, the shield tunneling construction method for soft soil strata includes:

[0033] Step S100, excavate a slurry pit beside the shield tunneling construction area;

[0034] Step S200, add water and bentonite into the slurry pit according to a preset ratio to prepare bentonite slurry;

[0035] Step S300, ferment the bentonite slurry until the viscosity of the bentonite slurry is greater than the preset viscosity;

[0036] Step S400, pumping the bentonite slurry in the slurry pit to the shield machine;

[0037] Step S500, the shield machine excavates the geological body according to preset parameters, and sprays the bentonite slurry onto the excavation face through the shield machine; wherein, the preset parameters include cutter head rotation speed, propulsion speed, thrust, and control torque, the cutter head rotation speed is 1.5 r / min to 2 r / min, the propulsion speed is 1 mm / min, the thrust is less than 4000 KN, and the control torque is less than 400 kN·m.

[0038] The technical solution of the present invention can effectively fill the voids between soil particles and form a dense mud film by using the bentonite slurry prepared in steps S200 to S400 and spraying it onto the excavation face during the excavation process (step S500). This mud film can significantly reduce the permeability coefficient of the geological body, thereby improving the impermeability and bearing capacity of the geological body, effectively inhibiting the instability of the soft soil stratum, reducing the occurrence of sand gushing and water gushing phenomena, ensuring the stability and safety of the construction area, and ensuring the quality of shield construction. By spraying bentonite slurry onto the excavation face, the geological body can also have a lower internal friction angle, thereby reducing the cutter head torque and effectively reducing the wear of the cutter head. Controlling the cutter head rotation speed of the shield machine at 1.5 r / min to 2 r / min, setting the propulsion speed to 1 mm / min, making the thrust less than 4000 KN, and making the control torque less than 400 kN·m can make the shield machine excavate the soft soil stratum more smoothly, thereby effectively avoiding the instability of the soft soil stratum. The shield construction method for soft soil stratum provided by the present invention can effectively avoid the instability of the soft soil stratum during the shield construction process in the soft soil stratum, thereby improving the quality and safety of shield construction.

[0039] Refer to Figure 2 , in an embodiment of the present invention, the shield construction method is used to excavate the geological body from the starting section to the receiving section;

[0040] Step S200 includes:

[0041] Step S210, when excavating the starting section or the receiving section, adding water and bentonite to the slurry pit according to a first ratio to prepare the bentonite slurry; wherein, the first ratio is that water and bentonite are mixed at a ratio of 4:1.

[0042] Specifically, for the bentonite slurry prepared by mixing water and bentonite in a ratio of 4:1, since the geological body is more unstable during shield operation in the receiving section and the starting section, the bentonite slurry prepared in a ratio of 4:1 can form a relatively viscous mud film, effectively avoiding the instability of the soft soil stratum, thereby improving the quality and safety of shield construction.

[0043] Refer toFigure 2 , in an embodiment of the present invention, step S200 further includes:

[0044] Step S220, when excavating the position between the launching section and the receiving section, add water and bentonite into the slurry pit according to a second ratio to prepare the bentonite slurry; wherein, the second ratio is that water and bentonite are mixed in a ratio of 6:1.

[0045] Furthermore, compared with the launching section and the receiving section, the geological body at the position between the launching section and the receiving section is relatively stable. Therefore, a lower ratio can be used to prepare the bentonite slurry, which can meet the requirements of shield construction at the position between the launching section and the receiving section and can effectively save costs.

[0046] In an embodiment of the present invention, the bentonite is sodium-based bentonite, and the sodium-based bentonite has strong plasticity and adhesiveness, which makes the bentonite slurry formed by the sodium-based bentonite have better adhesiveness, thereby effectively preventing the instability of the soft soil stratum.

[0047] In an embodiment of the present invention, the preset viscosity is 60 mPa·s.

[0048] The present invention also proposes a slurry supply system. The slurry supply system is applied to the shield construction method in soft soil strata. The slurry supply system includes a slurry pit. The specific method of the shield construction method in soft soil strata refers to the above embodiments. Since this slurry supply system adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0049] In an embodiment of the present invention, the slurry supply system further includes a conveying pipeline, a water supply device, and a bentonite supply device. The water supply device is used to supply water to the slurry pit, the bentonite supply device is used to supply bentonite to the slurry pit, and the conveying pipeline is used to pump the bentonite slurry in the slurry pit to the shield machine.

[0050] Specifically, through the water supply device and the bentonite supply device, water and bentonite can be continuously supplied to the slurry pit, which is convenient for supply. Thus, the bentonite slurry can be continuously prepared in the slurry pit with high preparation efficiency. After preparation, the bentonite slurry can be pumped to the shield machine through the conveying pipeline, which is simple and convenient.

[0051] In an embodiment of the present invention, the water supply device includes a water delivery pipe for inputting water into the slurry pit. The bentonite supply device includes a storage bin for storing bentonite and a conveyor belt for transporting the bentonite to the slurry pit.

[0052] Specifically, water can be supplied to the mud pit through a water pipe, and bentonite in the storage bin can be transported to the mud pit through a conveyor belt to supply bentonite to the mud pit, which is simple and convenient and effectively reduces the labor intensity of workers.

[0053] In an embodiment of the present invention, the mud supply system further includes a controller. The water pipe is provided with a proportional valve. The controller is used to control the proportional valve to control the flow rate of water input into the mud pit by the water pipe, and the controller is also used to control the conveying speed of the conveyor belt.

[0054] Furthermore, by controlling the proportional valve and the conveyor belt through the controller, proportional control of water and bentonite supplied to the mud pit can be achieved, thereby realizing the automatic preparation of bentonite slurry with a higher degree of automation.

[0055] The present invention also proposes a shield machine. The shield construction method for soft soil strata is applied to this shield machine. The shield machine includes a plurality of injectors arranged at intervals. The injectors are used to inject bentonite slurry onto the excavation face. The specific method of the shield construction method for soft soil strata refers to the above embodiments. Since this mud supply system adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0056] Specifically, through a plurality of injectors, the bentonite slurry can be sprayed onto the excavation face more evenly and comprehensively, thereby more effectively preventing instability during shield tunneling in soft soil strata.

[0057] The above is only an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A shield construction method for soft soil strata, characterized in that: The shield construction method comprises: Excavate a slurry pond next to the shield construction area; Adding water and bentonite in a preset ratio into the mud pool to prepare bentonite slurry; fermenting the bentonite slurry until the viscosity of the bentonite slurry is greater than a preset viscosity; Pumping the bentonite slurry in the mud pool to a shield machine; The shield machine excavates the geological body according to preset parameters, and sprays the bentonite slurry on the excavation surface through the shield machine; wherein the preset parameters include cutter head rotation speed, propulsion speed, thrust, and control torque, the cutter head rotation speed is 1.5r / min~2r / min, the propulsion speed is 1mm / min, the thrust is less than 4000KN, and the control torque is less than 400kN·m.

2. The shield construction method for soft soil strata according to claim 1, characterized in that: The shield construction method is used to excavate the geological body from the starting section to the receiving section; The step of adding water and bentonite in a preset ratio in the mud pool to prepare bentonite slurry comprises: When excavating the starting section or the receiving section, water and bentonite are added to the mud pool in a first ratio to prepare the bentonite slurry; wherein the first ratio is a 4:1 ratio of water to bentonite.

3. The shield construction method for soft soil strata according to claim 2, characterized in that: The step of adding water and bentonite in a preset ratio into the mud pool to prepare bentonite slurry also includes: When excavating the position between the starting section and the receiving section, water and bentonite are added to the mud pool in a second ratio to prepare the bentonite slurry; wherein the second ratio is a 6:1 ratio of water to bentonite.

4. The shield construction method for soft soil strata according to claim 1, characterized in that: The bentonite is sodium bentonite.

5. The shield construction method for soft soil strata according to claim 1, characterized in that: The preset viscosity is 60 mPa·s.

6. A mud supply system, characterized in that: The mud supply system is in the shield construction method for soft soil strata according to any one of claims 1 to 5, and the mud supply system comprises a mud pool.

7. The mud supply system according to claim 6, characterized in that: The mud supply system also includes a conveying pipeline, a water supply device and a bentonite supply device. The water supply device is used to supply water to the mud pool, the bentonite supply device is used to supply bentonite to the mud pool, and the conveying pipeline is used to pump the bentonite slurry in the mud pool to the shield machine.

8. The mud supply system according to claim 7, characterized in that: The water supply device comprises a water pipe, which is used to input water into the mud pool. The bentonite supply device comprises a storage tank and a conveyor belt, which is used to store the bentonite and the conveyor belt is used to convey the bentonite to the mud pool.

9. The mud supply system according to claim 8, characterized in that: The mud supply system also includes a controller. The water pipe is provided with a proportional valve. The controller is used to control the proportional valve to control the flow rate of water input from the water pipe to the mud pool. The controller is also used to control the transmission speed of the conveyor belt.

10. A shield machine, characterized in that: The shield construction method for soft soil strata according to any one of claims 1 to 5 is applied with the shield machine, and the shield machine includes a plurality of injectors arranged at intervals, and the injectors are used to inject bentonite slurry onto the excavation face.

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