WO2021213098A1

WO2021213098A1 - High-efficiency normal-pressure tool replacement construction method for water-rich sandy cobble stratum

Info

Publication number: WO2021213098A1
Application number: PCT/CN2021/081905
Authority: WO
Inventors: 吕涛; 尹苏江; 孙发全; 佟方硕; 张凯; 李辉; 崔广宇; 刘晓迪; 张惠春; 张彤; 吴健
Original assignee: 中铁九局集团有限公司; 中铁九局集团第四工程有限公司
Priority date: 2021-02-22
Filing date: 2021-03-19
Publication date: 2021-10-28
Also published as: LU501847B1; CN112576267B; CN112576267A

Abstract

A high-efficiency normal-pressure tool replacement construction method for a water-rich sandy cobble stratum. According to the construction method, any two adjacent plain piles (10) are meshed together, such that the reinforcing integrity effect is better. The construction method shows high stratum reinforcing speed and high safety in tool replacement operation, and can shorten the construction period and save on costs. The construction method can reduce noise and vibration, has a low impact on stratum and the surrounding environment, and does not require any slurry operation, thereby making a construction site clean, reducing ground pollution, saving on energy, and meeting green construction standards and requirements.

Description

High-efficiency atmospheric pressure tool change construction method for water-rich sand and pebble formation

Technical field

The invention belongs to the field of drilling into soil layers and rocks, and specifically relates to a high-efficiency normal-pressure tool change construction method for water-rich sand and pebble formations.

Background technique

With the development and application of shield construction in urban rail transit, water-rich sand and gravel stratum is a difficult and challenge for shield construction. Shield construction requires the use of shield machines in the high-end assembly field. The following problems still exist during the construction of the water-rich sand and pebble stratum by the machine: the excavation of the stratum has very serious wear on the tools. If the worn tools are not replaced in time, the service life of the cutter head and the cutter of the shield machine will be affected and the shield will be caused. The excavation parameters of the structure are abnormal, which seriously affects the progress of the construction period. In the prior art, in order to prevent the cave from collapsing during tool replacement, the jet grouting pile and sleeve valve tube grouting technology are often used to reinforce the ground. However, these two stratum reinforcement technologies can only be drilled and cored to monitor the strength of the pile body 28 days after the construction is completed, which seriously affects the construction period; and the above-mentioned reinforcement method uses a large amount of grouting liquid, which causes pollution to the ground and wastes resources.

Therefore, there is a need to provide an improved technical solution for the above-mentioned shortcomings of the prior art.

Summary of the invention

The purpose of the present invention is to provide a high-efficiency normal-pressure tool-changing construction method for water-rich sand and pebble formations, so as to at least solve the problems of long construction period and waste of resources by using jet grouting piles and sleeve valve tube grouting for stratum reinforcement.

In order to achieve the above objectives, the present invention provides the following technical solutions:

A high-efficiency normal-pressure tool change construction method for water-rich sand and pebble formations. The normal-pressure tool change construction method includes the following steps:

Step S1: Determine the tool replacement position in front of the shield machine along the tunneling direction;

Step S2, before the tool change operation, a plurality of water-stop rings are constructed behind the tube segment wall of the shield machine, and the plurality of water-stop rings are continuously constructed, and the plurality of water-stop rings are arranged along the axial direction of the shield machine ；

Step S3, at the determined tool replacement position, construct double-row plain piles, and any two adjacent plain piles are occluded together;

Step S4, turn on the shield machine, cut the cutter head of the shield machine into the pile and stop it;

Step S5, dilute the gas in the earth silo of the shield machine, and open the silo after the gas content in the earth silo meets the requirements;

Step S6: After the operator enters the soil bin, first check the stability of the soil, then check the tool wear, turn the cutter head, turn the tool to be replaced to a working position that is convenient for the operator to replace, and then turn on the tool to be replaced. After the tool is replaced, The soil bin was closed, and the shield machine resumed tunneling.

Beneficial effects:

(1) The normal pressure tool change construction method of the present invention has good operability. Compared with the common method of using jet grouting piles and sleeve valve tube grouting to reinforce the ground, the construction method of the present invention adopts solid piles for reinforcement and has more flexible position selectivity, and any two adjacent solid piles occlude each other. , Which makes the effect of strengthening the integrity better.

(2) The normal pressure tool change construction method of the present invention has little pollution. Compared with the method of using jet grouting piles and sleeve valve pipe grouting to strengthen the ground, this construction method has no noise and vibration, and has little impact on the ground and the surrounding environment. Mud operation makes the construction site clean, reduces ground pollution, saves energy, and meets the requirements of green construction specifications.

(3) The normal pressure tool change construction method of the present invention has a high speed to reinforce the stratum, greatly saves the construction period and saves the cost. Reinforce the stratum by grouting with jet grouting piles and sleeve valve pipes. Generally 28 days after the completion of construction, drilling and coring are started to test the strength of the pile body, while the present invention adopts the plain pile reinforcement to complete the pile strength after 2 to 3 days. Warehouse requirements.

(4) The normal pressure tool change construction method of the present invention has high tool change operation safety. Considering the airtightness of sand and gravel formations, compared with the operation under pressure, the tool change process under normal pressure is safe and reliable, the tool change work is safe, and the safety state of the working environment is significantly improved.

(5) The normal pressure tool changing construction method of the present invention has a short opening and changing tool period. After the pile reinforcement meets the requirements, the tool can be replaced under atmospheric pressure. The tool replacement takes about 3 to 5 days. However, in the prior art, when the mud film is established, it takes about 15 to 25 days for the tool to change into the warehouse under pressure. .

(6) The normal pressure tool change construction method of the present invention has a high economic ratio. The equipment and materials involved in the construction method measures are all conventional engineering machinery and materials, and there is no need to purchase additional expensive equipment and materials. At the same time, compared with the tool change under pressure, the labor cost of the normal pressure tool change is lower.

Description of the drawings

Figure 1 is a flow chart of the normal pressure tool change construction method in an embodiment of the present invention;

Figure 2 is a schematic diagram of the occlusal construction of the plain pile in the embodiment of the present invention;

Figure 3 is a schematic diagram of a double-row plain pile and a shield machine in an embodiment of the present invention;

Figure 4 is a schematic diagram of ventilation before opening a warehouse in an embodiment of the present invention.

In the picture: 10, plain pile; 20, cutter head; 30, shield body; 40, soil bin; 50, foam system; 60, foam pipeline; 70, original pressure holding system pipeline.

Detailed ways

According to a specific embodiment of the present invention, as shown in Figs. 1-4, the present invention provides a high-efficiency normal-pressure tool change construction method for water-rich sand and pebble formations. Quickly reinforce the stratum with plain piles to realize tool inspection and replacement under normal pressure. Plain pile refers to a pure concrete pile without steel bars in the occlusal pile. The normal pressure tool change construction method is used to replace the tools with a large amount of wear under normal pressure. The principle of the atmospheric pressure tool change construction method is that after determining the position of opening and changing the tool, the ground is reinforced by the method of occluding and reinforcing the plain pile. After the cutter head of the shield machine cuts into the pile body, the tool is inspected and replaced. At this time, the tunnel face of the shield machine is a double-row plain pile concrete protection wall, which has good self-stability. The tunnel face contacted by the cutter head can withstand the pressure of the buried deep soil. The shield machine does not need to open the warehouse. Pressure retention can also ensure that the ground does not sink and the tunnel face does not collapse. After the tool replacement process is completed, a comprehensive inspection of the soil bin and the front of the cutter head is carried out, and the tunneling machine will resume tunneling after meeting the requirements. The atmospheric pressure tool change construction method of the present application can perform efficient tool inspection and replacement operations in water-rich sand and pebble formations on the premise of balancing the economy and safety of the tool change operations.

The high-efficiency normal-pressure tool change construction method for water-rich sand and pebble formation includes the following steps:

Step S1: Determine the tool replacement position in front of the shield machine along the tunneling direction.

During the tunneling process of the shield machine, carefully analyze the tunneling parameters of the shield. After discovering the abnormality of the tunneling parameters, immediately analyze the cause of the abnormality to determine whether the tools need to be inspected and replaced. Through the detailed geological report and supplementary geological survey results, understand the plan The geological conditions of the tool-changing position, and a detailed investigation of the surface conditions, along the tunneling direction, determine the tool-changing position in front of the shield machine, and the tool-changing position should avoid buildings (structures), pipelines, and busy roads as much as possible , To reduce the impact on citizens’ lives.

Step S2, before the tool change operation, a plurality of water-stop rings are constructed behind the tube segment wall of the shield machine, and the plurality of water-stop rings are continuously constructed, and the plurality of water-stop rings are along the axial direction of the shield machine Arrangement; behind the wall of the segment is the part outside the outer circumference of the segment, the water stop ring wraps the segment from the circumferential direction, and the water stop ring has a cylindrical structure; the construction of the water stop ring should ensure that the distance between the water stop ring and the shield At least 5 rings away from the tail of the tunneling machine, that is, the water-stop ring closest to the shield machine is at least 5 water-stop ring widths away from the tail of the shield machine to avoid blocking the tail of the shield machine due to grouting during the construction of the water-stop ring; The water-stop ring is constructed to block the subsequent water coming, and the multi-ring water-stop ring is continuously constructed. In this embodiment, three water-stop rings are used for continuous construction to ensure that the water-stop ring has better integrity and better waterproof effect.

In order to prevent the groundwater behind the shield 30 from directly pouring into the cutter head 20 from the shield body 30 when the shield machine is opened for the knife change operation, which affects the knife change operation, it is necessary to effectively isolate the groundwater behind the pipe segment wall. The construction of the water stop ring should ensure that there are 5 rings from the tail of the shield and be constructed continuously for 3 rings. The water stop ring is constructed by injecting double slurry (cement-water glass double slurry) after the pipe segment wall. The slurry ratio meets the cement slurry: water The glass mass ratio is 1:1, the grouting pressure is controlled at 0.2～0.3MPa, the grouting volume is controlled at 2～3m3 per ring, the grouting end standard is double controlled by the grouting pressure and the grouting volume, that is, when grouting When both the pressure and the grouting volume reach the set value range, the grouting can be completed to ensure that the gaps behind the pipe wall are filled tightly and meet the water-stop requirements.

In step S3, at the determined tool replacement position, double-row plain piles 10 are constructed, and any two adjacent plain piles 10 are interlocked with each other.

Protection of the shield machine during the construction of the plain pile 10: Before the construction of the plain pile 10, determine whether the actual position of the plain pile 10 conflicts with the position of the shield machine. The soil bin 40 of the shield machine is filled with bentonite to prevent concrete from being poured in, and concrete is poured In the front of the shield machine cutter head 20, the soil bin 40 and the shield machine shield 30 are driven into a sufficient amount of bentonite to protect the cutter head 20 and shield body 30 from being locked by concrete; pour plain piles 10 During the concrete period, pay attention to the pressure change of the shield soil bin 40 and the volume of concrete pouring at any time. If the pressure of the shield soil bin 40 is found to rise, stop pouring immediately. If the volume is found to be excessive, stop pouring immediately and rotate the shield cutter head 20 Check whether the torque is abnormal. If it is found to be abnormal, immediately inject enough bentonite and pump air to start slagging, and replace the concrete in the warehouse with bentonite.

Construction of plain piles 10, when ground conditions, underground pipelines, and building conditions permit, 15 C20 concrete rotary drilled piles 10 are used to interlock with each other and form two rows of piles directly in front of the cutter head 20. (Ie double-row plain piles 10), forming a protective wall. The diameter of the pile 10 ranges from 1.4 to 1.6m (optionally, 1.4m, 1.5m, 1.6m). , The cutter head of the shield machine cuts into half of the diameter of the pile, and then it stops to open the warehouse and change the tool. The rotary drill is a long auger drill, the specification is SZKL600B.

In this embodiment, the plain piles 10 are double-row plain piles, and a row of plain piles 10 close to the cutter head 20 is constructed first. In order to facilitate cutting and occlusion and reduce the disturbance between adjacent holes during the construction process, jump piles are used for construction, as shown in Figure 2, that is, during construction, the two adjacent plain piles 10 are divided into A pile and B pile, A pile Including A1 pile, A2 pile, A3 pile, A4 pile, B pile includes B1 pile, B2 pile, B3 pile. Construct A1 pile, A2 pile, A3 pile, A4 pile first, then construct B1 pile, B2 pile, B3 pile. The purpose of using jumping piles is to minimize interference between piles and ensure the quality of forming. A pile uses ultra-retarded concrete. It is required that the construction of pile B must be completed before the concrete of pile A is condensed, so that during the construction of pile B, a rotary drilling rig is used to cut the 1/5 diameter intersecting part of adjacent pile A from the vertical direction. Then pour the concrete of pile B to realize the occlusion of pile A and pile B. Two adjacent plain piles 10 are interlocked with each other, which not only makes the overall structural integrity of the double-row plain piles 10 better and more complete, but also compared to the current jet-grouting pile and sleeve valve tube grouting reinforcement technology, the double-row The amount of concrete used for occluding the plain piles 10 with each other is greatly reduced.

The pile 10 is constructed to 1 meter below the bottom of the shield machine at the opening position, and the top of the pile 10 is raised to a position 5 meters above the vault of the shield machine. That is, the bottom of the pile 10 is at least lower than the bottom of the shield machine. 1m, the top of the pile 10 is higher than the top of the shield machine by at least 5m. The space above the pile top of the pile 10 is backfilled with pebble soil. This arrangement can further reduce the amount of concrete used in the pile 10, and there is a certain distance between the top of the pile 10 and the ground, so that the pile 10 will not be affected by the later on the ground. The structure has an impact.

In step S4, the shield machine is turned on, the cutter head 20 of the shield machine is cut into the pile 10 and the machine stops.

In this embodiment, the diameter of the pile 10 is 1.5 m. Turn on the shield machine, and stop when the cutter head 20 of the shield machine cuts into the 1/2 position of the diameter of the first row of pile walls, that is, the cutter head 20 cuts into the pile wall (that is, the double-row plain pile 10) after 75-80 cm and then stops. Warehouse tool change operation. The position deviation of the plain pile 10 is not more than 50mm, the deviation of verticality is not more than 1%, and the position can only be opened after the strength meets the conditions for opening the position.

The cutter head 20 needs to grind the pile (grinding the pile, that is, cutting into the prime pile 10) about 75-80cm. During the pile grinding, the forward speed of the shield machine is strictly controlled to about 5mm/min. The thrust and torque are adjusted according to the actual situation, and the various items are minimized. Parameter, in order to avoid excessive thrust, after the cutter head 20 completely enters the pile, reduce the soil pressure, try to remove the soil in the soil bin 40 as much as possible, prepare for opening, and strengthen monitoring at the ground position to ensure ground safety. control.

Step S5, dilute the gas in the soil bin 40 of the shield machine, and open the bin after the gas content in the soil bin 40 meets the requirements. The gas in the soil bin 40 is discharged to the tail of the shield machine to form a circulating air flow to dilute the gas in the soil bin.

Specifically, the air circulation in the soil bin 40 before opening the warehouse mainly utilizes the foam system 50 of the rotary joint to blow wind into the front of the cutter head 20 through the foam pipe 60, and the original pressure holding system pipeline 70 on the bulkhead of the soil bin 40 It is an exhaust channel, exhausted to the tail part of the shield machine to form a circulation and dilute the gas in the soil bin 40. The gas detector is used for detection. If the gas content exceeds the standard, the gas detector will issue an alarm. After the gas content detection meets the requirements, the gas content requirements are shown in Table 1 below before opening the warehouse. During the tool change operation in the soil bin 40, the air circulation in the soil bin 40 mainly uses the holes on the partition of the soil bin 40 (the water and electricity inlet holes reserved in the original soil bin 40) to blow in the wind, that is, use The holes reserved on the partition of the soil bin 40 are used as air inlets, and the entrance and exit of the soil bin 40 are exhaust ports to form a circulation and ensure the air quality in the soil bin 40. The ventilation in the cave mainly uses the press-in ventilator outside the cave to provide air to form a circulation. While ventilating the cave and the warehouse, gas detection is carried out to ensure the safety of the working environment of the operators.

Table 1 Reference table of gas detection standards

气体种类Gas type	容许最高浓度Allowable maximum concentration	标准限量Standard limit
O ₂ O ₂	19.5％～23％19.5%～23%	≥20≥20
CH ₄ CH ₄	不超过1％Not more than 1%	＜0.75＜0.75
CO ₂ CO ₂	9000mg/m ³ 9000mg/m ³	≤0.5≤0.5
COCO	不超过0.0024％Not more than 0.0024%	≤30≤30
NO _X(氮氧化物) NO _X (nitrogen oxide)	5mg/m ³ 5mg/m ³	≤5≤5
SO ₂ SO ₂	5mg/m ³ 5mg/m ³	≤0.0005≤0.0005
H ₂S H ₂ S	10mg/m ³ 10mg/m ³	≤0.00066≤0.00066
NH ₃ NH ₃	30mg/m ³ 30mg/m ³	≤0.064≤0.064

Step S6: After the operator enters the soil bin 40, first check the stability of the soil, and then check the wear of the tool. Turn the cutter head 20 to rotate the tool to be replaced to a working position that is convenient for the operator to replace. After the tool is replaced, close the soil. In warehouse 40, the shield machine resumes tunneling. That is, after the operator enters the warehouse, first check the stability of the soil, wash the cutter head and the tools on the cutter head with high pressure water under the condition of ensuring safety, measure the wear of the tools with a tool ruler, and replace the worn tools; shield machine After advancing 180-220mm, open the soil bin again to check the tools, tighten the tool fixing bolts again, and the shield machine will resume tunneling; the order of tool inspection is: peripheral hob, side scraper, peripheral center hob, and center knife.

Step S601: Observe the face of the face. According to the unearthed condition of the propelling screw machine, the moisture content of the soil, and the order of unearthed clearing was issued, the soil in the soil bin 40 was lowered to about 2/3 of the warehouse wall, the ball valve on the warehouse wall was opened, and the 1.5-meter-long steel bar was used for inspection holes. Determine the water content and soil conditions in the soil bin 40; use a crowbar to pry open the door of the soil bin 40, observe whether there is water and sand exposed in the gap, and conduct harmful gas detection. After the gas detection meets the opening conditions, the operator opens The gate of the human warehouse arrives in front of the door of the soil warehouse 40. Open the soil warehouse 40. After the door of the soil warehouse 40 is opened, first judge the stability of the tunnel surface and ventilate the soil warehouse 40 for 30 minutes. At the same time, the gas was detected again and the soil stability in front of the cutter head 20 was judged. The operator advanced to the soil bin 40 to observe the geological conditions and other conditions of the tunnel face. The personnel entering the bin must be tied with ropes and pulled by the personnel outside the bin. Tight, pull it out at any time if there are special circumstances.

Step S602, inspection of the tool. After the operator enters the warehouse, check the stability of the soil first. Under the condition of ensuring safety, flush the cutter head 20 and the tools with high pressure water to facilitate the inspection of the tool size. After the tools are clearly exposed, reconfirm the face of the pocket After the stability of the soil, the tool changer enters the soil bin 40 for tool inspection, mainly to check the degree of wear of the tool and whether there is eccentric wear. The inspection order of the tools is the priority inspection order: peripheral hob, side scraper, peripheral hob, center knife. Use the tool ruler to measure the wear of the tool, and make a record to determine the number and location of tool replacement. In the whole process of checking the tools, a special person shall be arranged to observe the stability of the soil at the gate of the pedestrian gate (that is, the position of the gate of the human warehouse). If the soil collapses, immediately notify the warehousing personnel to leave the warehouse, and close the hatch in time and tighten the bolts; Keep the walkie-talkie between the warehouse and the warehouse door. When the operator enters the warehouse, the gas detector is directly placed at the mouth of the soil warehouse to detect harmful gases at all times. After the warehouse is opened, uninterrupted ventilation must be maintained until the opening operation is completed.

In step S603, the tool is replaced. Rotate the tool changed by the cutter head 20 to a suitable working position to facilitate the operation in the cabin of the operator. When the tool is replaced, each tool is removed, one is transported out and the other is replaced, and then the other tool is removed. When removing the tool, Beware of the falling of small pieces, which will affect the progress of the operation and adversely affect the later excavation. After the replacement is completed, turn the cutter head 20, tighten all the tool bolts, clean up the tools and materials used, confirm that they are correct or take out all of them, close the hatch, and complete the tool change work. After the new tool is replaced, the shield machine is advanced 180～220mm (optional, 180mm, 190mm, 200mm, 210mm, 220mm) (at this time, the cutter head 20 of the shield machine is still in the double-row plain pile 10 , To ensure that the ground does not settle and the tunnel face does not collapse) Open the hatch again to check the tools and tighten the bolts; after the tools are processed, perform a comprehensive inspection on the front of the soil bin 40 and the cutter head 20 to avoid tools and debris left behind Inside the soil warehouse 40. After confirmation, close all reserved air supply ports, exhaust ports, valves and warehouse doors. After the closing conditions meet the requirements, the shield machine will resume tunneling. After the shield machine advances 180-220mm, the newly replaced tools are under over-stress, and all the tools are tightened again to ensure the stable fixation of the cutters and ensure that the cutters can have a better use effect when they are firmly fixed.

Ground monitoring is required when opening the warehouse. Specifically, when opening a warehouse for inspection and replacement of tools, in order to understand the ground subsidence in a timely and accurate manner, it is necessary to arrange ground monitoring points at the opening mileage and conduct ground inspections. When the ground subsidence value is found to be abnormal, the monitoring personnel report to the project department in a timely manner. According to the data analysis, the Ministry makes corresponding adjustments and measures. When the warehouse is officially opened for construction, the monitoring frequency is maintained at 4 hours/time, and the project department can make adjustments according to the actual situation. In actual monitoring, the monitoring value reaches 50% of the control standard as the early warning value. When the monitoring value reaches 70% of the control standard, it enters the security alert range. It is necessary to focus on monitoring the area and adopt certain control measures. When the monitoring value reaches the warning value, the measurement group is divided into 2 shifts, and the monitoring frequency is encrypted to once every 2 hours.

Claims

The high-efficiency normal-pressure tool-changing construction method for water-rich sand and pebble formations is characterized in that the normal-pressure tool-changing construction method includes the following steps:

Step S1: Determine the tool replacement position in front of the shield machine along the tunneling direction;

Step S2, before the tool change operation, a plurality of water-stop rings are constructed behind the tube segment wall of the shield machine, and the plurality of water-stop rings are continuously constructed, and the plurality of water-stop rings are arranged along the axial direction of the shield machine ；

Step S3, at the determined tool replacement position, construct double-row plain piles, and any two adjacent plain piles are occluded together;

Step S4, turn on the shield machine, cut the cutter head of the shield machine into the pile and stop it;

Step S5, dilute the gas in the earth silo of the shield machine, and open the silo after the gas content in the earth silo meets the requirements;

Step S6: After the operator enters the soil bin, first check the stability of the soil, then check the tool wear, turn the cutter head, turn the tool to be replaced to a working position that is convenient for the operator to replace, and then turn on the tool to be replaced. After the tool is replaced, The soil bin was closed, and the shield machine resumed tunneling.
The tool change construction method according to claim 1, wherein the water stop ring is formed by grouting, and when the grouting pressure and the grouting amount both reach the set value range, the grouting ends;

The slurry mixing ratio of the water stop ring satisfies the cement slurry: water glass mass ratio of 1:1, the grouting pressure range is 0.2 to 0.3 MPa, and the grouting amount of each water stop ring is in the range of 2 to 3 m 3 ;

The water stop ring closest to the shield machine is at least five widths of the water stop ring from the tail of the shield machine.
The tool change construction method according to claim 1, characterized in that the double-row plain piles are constructed by jumping piles, and the two adjacent plain piles are divided into pile A and pile B. Pile A is constructed first, and pile B is constructed. pile.
The tool change construction method according to claim 3, wherein the A pile adopts ultra-retarded concrete, and the construction of the B pile must be completed before the concrete of the A pile is condensed;

When constructing Pile B, the drilling rig cuts the 1/5-diameter part of the concrete of the adjacent A pile from top to bottom, and then pours the concrete of the B pile to achieve the occlusion of the A pile and the B pile.
The tool change construction method according to claim 3, wherein the bottom of the plain pile is lower than the bottom of the shield machine by at least 1 m, and the top of the plain pile is higher than the top of the shield machine by at least 5 m;

The space above the top of the pile is backfilled with pebble soil.
The tool changing construction method according to claim 3, characterized in that the diameter of the raw pile is in the range of 1.4-1.6m, and the cutter head of the shield machine cuts into half of the diameter of the raw pile and then the machine is shut down for opening and tool change operations.
The tool change construction method according to claim 1, characterized in that, in step S5, the gas in the soil bin is discharged to the tail of the shield machine to form a circulating airflow to dilute the gas in the soil bin.
The tool change construction method according to claim 7, characterized in that, in step S5, during the opening operation, the holes reserved on the baffle of the soil bin are used as air inlets, and the entrance and exit of the soil bin are used as exhaust The air port forms a circulation to ensure the air quality in the soil bin.
The tool changing construction method according to any one of claims 1-8, characterized in that, before pouring the plain piles, a sufficient amount of bentonite is driven into the front of the cutter head of the shield machine, the soil bin and the shield body of the shield machine before pouring the plain piles to avoid The concrete forms a locked state on the cutter head and shield body of the shield machine;

When pouring the plain piles, pay attention to the pressure in the soil bin and the volume of concrete pouring. If the pressure in the soil bin increases or the volume exceeds the volume, stop pouring immediately and turn the shield machine cutter to check whether the torque is abnormal. If any abnormality is found, pour it immediately Sufficient amount of bentonite and aeration start to produce slag to replace the concrete in the soil bin.
The tool change construction method according to any one of claims 1-8, characterized in that, in step S6, after the operator enters the warehouse, first check the stability of the soil, and check the cutter head and the cutter head under the condition of ensuring safety. The tools on the upper part are rinsed with high-pressure water, the wear of the tools is measured with a tool ruler, and the worn tools are replaced; after the shield machine advances 180-220mm, open the soil bin again to check the tools, tighten the tool fixing bolts again, and the shield machine resumes tunneling ；

The order of tool inspection is: peripheral hob, side scraper, peripheral to center hob, and center knife.