阅读说明：本技术 盾构机带压开仓前的安全作业方法 (Safe operation method of shield machine before opening under pressure ) 是由 孙振中 孙振川 任颖莹 王发民 陈桥 韩伟锋 王凯 张合沛 秦银平 许华国 李宏 于 2019-10-12 设计创作，主要内容包括：本发明公开了一种盾构机带压开仓前的安全作业方法,包括盾尾密封、泥浆置换、保压和仓内气体置换,本发明盾尾密封工序能够起到盾构机密封保护的作用,有效保证盾尾止水效果,保证后续气压开仓作业的密闭性和防水效果；泥浆置换工序,能够在隧道开挖面形成泥膜,减少气压开仓时气体的泄漏并将地层中的水隔离,使土体稳定,增加地层的气密性效果,确保气压的密封性。保压工序可以检测泥膜的形成效果,确保仓内的压力,保证仓体的密闭性和密封效果；仓内空气置换,能够保证仓内的空气质量,排出仓内的有害气体,保证工作人员的安全,提高带压开仓的安全性。(The invention discloses a safe operation method before shield machine pressure opening, which comprises shield tail sealing, slurry replacement, pressure maintaining and gas replacement in a cabin, wherein the shield tail sealing process can play a role in shield machine sealing protection, effectively ensures the shield tail water stopping effect and ensures the tightness and waterproof effect of subsequent air pressure opening operation; and in the mud replacement process, a mud film can be formed on the tunnel excavation surface, so that the gas leakage is reduced when the cabin is opened under the air pressure, the water in the stratum is isolated, the soil body is stabilized, the air tightness effect of the stratum is improved, and the air pressure tightness is ensured. The pressure maintaining process can detect the forming effect of the mud film, ensure the pressure in the bin and ensure the tightness and sealing effect of the bin body; the air replacement in the bin can ensure the air quality in the bin, discharge harmful gas in the bin, ensure the safety of workers and improve the safety of opening the bin under pressure.)

1. A safe operation method of a shield machine before opening a cabin under pressure is characterized by comprising the following steps:

(1) shield tail seal

Increasing synchronous grouting amount at the opening position of the shield tunneling machine, wherein the synchronous grouting pressure is not more than 1.3 times of the formation pressure; meanwhile, the injection amount of grease at the shield tail is increased, and the shield tail sealing failure caused by the fact that the grouting pressure flows into the shield tail excessively is avoided;

the method comprises the following steps that (1) a hole of a grouting hole on a pipe piece is utilized to carry out supplementary grouting of cement-water glass slurry in a 2-10 ring behind a shield tail, polyurethane is injected from a radial hole of a shield body, and a closed water stop ring is formed outside a shield shell to ensure the filling compactness of the wall back grouting and prevent underground water behind the shield tail from flowing into the front side of a cutter head; after the cement-water glass slurry is refilled, the pressure of the air cushion bin is adjusted to be the opening pressure, and the shield tail water stopping effect is judged through the pressure change and the liquid level change of the slurry bin;

(2) slurry replacement

Injecting the puffed high-viscosity slurry into the excavation bin by adopting a synchronous grouting system of a shield machine, pressing the liquid level of the front air cushion bin to be reduced to 45-50%, keeping the central pressure of the excavation bin equal to the sum of the water and soil pressure of the point, starting to discharge slurry slowly by using a slurry discharge pipe when the liquid level of the air cushion bin is raised to about 70%, reducing the liquid level, continuing to inject new slurry into the excavation bin when the liquid level of the air cushion bin is reduced to 45-50%, and circulating the steps until the high-viscosity slurry is replaced;

(3) pressure maintaining device

After the slurry replacement in the step (2) is finished, starting to rotate the cutter head, controlling the rotation speed of the cutter head to be about 1r/min, and rotating the cutter head for 5-10 r; then, pressure maintaining is started, the pressure is increased by 0.1bar every 30min according to the initial pressure of the center of the excavation bin, the pressure maintaining is started when the final pressure is higher than the initial pressure by about 0.2-0.5 bar, the liquid level is controlled to be about 50%, and the pressure maintaining time is not less than 2 hours;

(4) in-bin gas replacement

High-pressure air is pressed into the air cushion bin by adopting a pressure maintaining system of the shield tunneling machine, an exhaust valve of the pressure maintaining system is opened for exhausting, and gas in the bin is replaced through air inlet-exhaust circulation on the premise of ensuring the pressure of the air cushion bin to be stable; the gas replacement in the bin is not less than 2 h;

before the opening operation, a valve connected with the air cushion bin is required to be opened in the human bin, a portable gas detector is adopted to detect the air quality in the air cushion bin, and the opening operation can be carried out after the air quality meets the requirements of the following table 1;

if the requirements of the table 1 are not met, the operation of the step (3) must be repeated until the air quality in the warehouse meets the standard requirements, and the warehouse can be opened for operation and construction.

2. The safe operation method of the shield machine before opening the warehouse under pressure according to claim 1, characterized in that the synchronous grouting amount is based on achieving the shield tail water stopping effect; if the water stopping effect in the step (1) is not ideal, the hole of the duct piece is opened after the shield tail is discharged to perform polyurethane refilling, so that the sealing effect of the shield tail is ensured.

3. The safe operation method of the shield machine before opening the cabin under pressure according to claim 1, wherein the viscosity of the high-viscosity slurry in the step (2) is 60 s-90 s, and the high-viscosity slurry is left to stand for 24h for puffing after the preparation is completed; the mud displacement is 1.2 times of the volume of the mud in the bin.

4. The safe operation method of the shield machine before opening the cabin under pressure according to claim 3, wherein when the slurry is replaced in the step (2), the pressure in the cabin needs to be higher than the working pressure by 0.2 bar-0.5 bar, the injection pressure of the high-viscosity slurry is not less than the opening pressure, and the pressure in the cabin needs to be kept basically stable in the process of injecting the high-viscosity slurry to replace the slurry in the cabin.

5. The safe operation method of the shield machine before opening the cabin under pressure according to claim 1, characterized in that a pressure holding test is carried out after the step (3): after the high-viscosity slurry is injected, continuously maintaining the pressure for not less than 2h, and rotating the cutter head for 2min every 30min, namely rotating the cutter head for 1min left and right respectively to ensure the forming quality of the mud film; after the pressure maintaining is finished, communicating the muddy water and the air cushion bin, reducing the liquid level to the minimum, standing for a period of time, observing and recording the liquid level and the pressure change in the bin, and if the liquid level and the pressure have no change or have small changes, proving that the film forming quality is good, the muddy water bin has good sealing effect, and can be used for the next operation; otherwise, the film is required to be formed again until a good sealing effect is achieved.

Technical Field

The invention relates to the technical field of shield tunneling, in particular to a safe operation method of a shield tunneling machine before opening a cabin under pressure.

Background

In order to better manage the cutter head and the cutter and serve shield tunneling, the operation process of the shield tunneling machine needs to be purposefully and pertinently opened under pressure. But tunnel shield constructs machine knife dish adopts ordinary pressure tool changing blade dish usually to be furnished with partial cutter wearing and tearing monitoring devices, under the general condition, when monitoring abnormity, cutter wearing and tearing, the staff can direct ordinary pressure change, need not take the area to press into the storehouse, the number of times and the risk of having significantly reduced area pressure open storehouse tool changing. Under special conditions, however, due to the conditions of bin blockage, row stagnation, cutter mud cake formation, abnormal tunneling parameters, cutter clamping, failure of sensors in the bin, failure of a stone crusher and the like caused by stratum geological change, improper tunneling operation or emergency conditions, the bin must be charged under pressure; before entering the warehouse, the preparation work of corresponding personnel, equipment, materials and tools is needed to be done, and the safe and smooth operation of opening the warehouse under pressure is ensured.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a safe operation method before the under-pressure opening of the shield machine, which can improve the safety of the under-pressure opening and enhance the safety guarantee of the under-pressure opening.

In order to solve the technical problems, the invention adopts the following technical scheme:

a safety operation method before shield tunneling machine pressure opening is designed, and comprises the following steps:

(1) shield tail seal

Increasing synchronous grouting amount at the opening position of the shield tunneling machine, wherein the synchronous grouting pressure is not more than 1.3 times of the formation pressure; meanwhile, the injection amount of grease at the shield tail is increased, and the shield tail sealing failure caused by the fact that the grouting pressure flows into the shield tail excessively is avoided;

the method comprises the following steps that (1) a hole of a grouting hole on a pipe piece is utilized to carry out supplementary grouting of cement-water glass slurry in a 2-10 ring behind a shield tail, polyurethane is injected from a radial hole of a shield body, and a closed water stop ring is formed outside a shield shell to ensure the filling compactness of the wall back grouting and prevent underground water behind the shield tail from flowing into the front side of a cutter head; after the cement-water glass slurry is refilled, the pressure of the air cushion bin is adjusted to be the opening pressure, and the shield tail water stopping effect is judged through the pressure change and the liquid level change of the slurry bin;

(2) slurry replacement

Injecting the puffed high-viscosity slurry into the excavation bin by adopting a synchronous grouting system of a shield machine, pressing the liquid level of the front air cushion bin to be reduced to 45-50%, keeping the central pressure of the excavation bin equal to the sum of the water and soil pressure of the point, starting to discharge slurry slowly by using a slurry discharge pipe when the liquid level of the air cushion bin is raised to about 70%, reducing the liquid level, continuing to inject new slurry into the excavation bin when the liquid level of the air cushion bin is reduced to 45-50%, and circulating the steps until the high-viscosity slurry is replaced;

(3) pressure maintaining device

After the slurry replacement in the step (2) is finished, starting to rotate the cutter head, controlling the rotation speed of the cutter head to be about 1r/min, and rotating the cutter head for 5-10 r; then, pressure maintaining is started, the pressure is increased by 0.1bar every 30min according to the initial pressure of the center of the excavation bin, the pressure maintaining is started when the final pressure is higher than the initial pressure by about 0.2-0.5 bar, the liquid level is controlled to be about 50%, and the pressure maintaining time is not less than 2 hours;

(4) in-bin gas replacement

High-pressure air is pressed into the air cushion bin by adopting a pressure maintaining system of the shield tunneling machine, an exhaust valve of the pressure maintaining system is opened for exhausting, and gas in the bin is replaced through air inlet-exhaust circulation on the premise of ensuring the pressure of the air cushion bin to be stable; the gas replacement in the bin is not less than 2 h;

before the opening operation, a valve connected with the air cushion bin is required to be opened in the human bin, a portable gas detector is adopted to detect the air quality in the air cushion bin, and the opening operation can be carried out after the air quality meets the requirements of the following table 1;

if the requirements of the table 1 are not met, the operation of the step (3) must be repeated until the air quality in the warehouse meets the standard requirements, and the warehouse can be opened for operation and construction.

Preferably, the synchronous grouting amount is based on achieving the shield tail water stopping effect; if the water stopping effect in the step (1) is not ideal, the hole of the duct piece is opened after the shield tail is discharged to perform polyurethane refilling, so that the sealing effect of the shield tail is ensured.

Preferably, the viscosity of the high-viscosity slurry in the step (2) is 60 s-90 s, and the high-viscosity slurry is kept stand for 24h for swelling after the preparation is finished; the mud displacement is 1.2 times of the volume of the mud in the bin.

Preferably, when the slurry is replaced in the step (2), the pressure in the bin needs to be higher than the working pressure by 0.2-0.5 bar, the injection pressure of the high-viscosity slurry is not less than the opening pressure, and the pressure in the bin needs to be kept basically stable in the process of injecting the high-viscosity slurry to replace the slurry in the bin.

Preferably, a pressure holding test is carried out after the step (3): after the high-viscosity slurry is injected, continuously maintaining the pressure for not less than 2h, and rotating the cutter head for 2min every 30min, namely rotating the cutter head for 1min left and right respectively to ensure the forming quality of the mud film; after the pressure maintaining is finished, communicating the muddy water and the air cushion bin, reducing the liquid level to the minimum, standing for a period of time, observing and recording the liquid level and the pressure change in the bin, and if the liquid level and the pressure have no change or have small changes, proving that the film forming quality is good, the muddy water bin has good sealing effect, and can be used for the next operation; otherwise, the film is required to be formed again until a good sealing effect is achieved.

The invention has the beneficial effects that:

in the safety operation method before the shield machine is opened under pressure, the shield tail sealing process can play a role in protecting the shield machine, so that the shield tail water stopping effect is effectively ensured, and the tightness and the waterproof effect of the subsequent air pressure opening operation are ensured; and in the mud replacement process, a mud film can be formed on the tunnel excavation surface, so that the gas leakage is reduced when the cabin is opened under the air pressure, the water in the stratum is isolated, the soil body is stabilized, the air tightness effect of the stratum is improved, and the air pressure tightness is ensured. The pressure maintaining process can detect the forming effect of the mud film, ensure the pressure in the bin and ensure the tightness and sealing effect of the bin body; the air replacement in the bin can ensure the air quality in the bin, discharge harmful gas in the bin, ensure the safety of workers and improve the safety of opening the bin under pressure.

Detailed Description

The following examples are given to illustrate specific embodiments of the present invention, but are not intended to limit the scope of the present invention in any way. The apparatus elements referred to in the following examples are, unless otherwise specified, conventional apparatus elements; the industrial raw materials are all conventional industrial raw materials which are sold on the market, if not specifically mentioned.