CN105257309B - In a kind of layer of sand in balancing earth-pressure shielding machine storehouse slip casting tool changing construction method - Google Patents

Abstract

The invention provides a construction method for grouting and tool change in the earth pressure balance shield machine chamber in the sand layer. The steps of the method include: the first step, injecting bentonite mud into the soil chamber; the second step, replacing the soil with air The muck slurry in the bin; the third step, filling the void under pressure; the fourth step, backfilling the soil bin; the fifth step, clearing the bin and changing the tool; the sixth step, resuming the excavation. The invention aims at the problem of earth pressure balance shield machine filling bin and tool change under the condition of no ground reinforcement in the sand layer, avoids the difficult advanced grouting construction operation, clarifies the grouting construction operation mode, and prevents the cement mortar in the screw conveyor Hardening causes equipment damage, which effectively reduces the construction workload; the invention has short construction time, high efficiency and strong safety.

Description

A construction method for grouting and tool change in the chamber of earth pressure balance shield tunneling machine in sand layer

technical field

The invention relates to a construction method in the technical field of tunnel engineering, in particular to a construction method for grouting and tool change in an earth pressure balance shield machine chamber in a sand layer.

Background technique

In recent years, with the continuous advancement of China's urbanization process, the problem of urban traffic congestion has become more and more serious. The construction of subway tunnels can solve or improve the current situation of urban traffic, so it has been widely used. These subway tunnels need to be constructed using the shield method. The earth pressure balance shield method is a fully mechanical construction method commonly used in shield tunneling construction. It uses an earth pressure balance shield machine to cut the soil through the cutter head in front of the shield machine and pass the muck through the screw conveyor. After being transported out of the tunnel, the shield machine is pushed forward under the support of the casing and segments. During the shield tunneling process, it is necessary to continuously cut rock and soil. When cutting hard rock formations, the cutter will cause excessive wear, bursting and jamming, which will damage the structure of the cutter head, affecting normal construction operations, and the cutter needs to be replaced in time. Due to the different geological conditions and surrounding environments of each city, it is necessary to replace the shield machine tool under various geological conditions. The traditional normal pressure tool change method, under pressure tool change method and ground reinforcement tool change method have been widely used in the shield tunneling construction process. However, when the shield machine is in the sand layer, the ground above the excavation surface of the shield machine cannot be reinforced, and the sand layer has poor self-stabilization ability and serious air leakage, there are still many technical difficulties and problems in the construction of shield machine tool replacement. Serious safety hazard. The traditional construction method of shield machine tool replacement is difficult to adopt in the sand layer without ground reinforcement conditions, resulting in the unfavorable situation of difficult tool change of shield machine, low construction efficiency and long construction period.

After searching the literature of the prior art, it was found that the invention patent "[application number is 201210268682.5], the name of the invention: the construction method of shield tunneling tool change under pressure in water-rich silt and silt strata under the railway track", the above-mentioned patent shield machine replacement Knife construction requires the use of high-pressure rotary grouting piles to reinforce the soil at the knife change site, and its application is limited without ground reinforcement. Invention patent "[Application No. 201010554969.5], title of the invention: a method for changing the tool of a shield machine for tunnel construction". warehouse replacement filling, but did not mention the specific replacement filling method and specific replacement filling construction operation method. In this patent, the injection of cement mortar in the soil bin and the output of muck are carried out simultaneously. During the process of replacing the muck in the soil bin with cement mortar, it is impossible to prevent the cement mortar in the screw conveyor from hardening, resulting in equipment damage. This patent uses advanced grouting to reinforce the upper soil of the shield machine, but the advanced grouting process is complicated, the operation is difficult, and the construction speed is slow. Therefore, there is an urgent need for a fast and safe method for tool change of the earth pressure balance shield machine in the sand layer without ground reinforcement.

Contents of the invention

Aiming at the defects in the prior art, the purpose of the present invention is to provide a construction method for grouting and tool change in the earth pressure balance shield machine cabin in the sand layer, which overcomes the inability of the ground to be reinforced and the gas retention capacity of the sand layer in the prior art. Poor, easy to block the grouting port, unclear grouting construction operation method, difficult construction of advance grouting reinforcement and heavy workload and other shortcomings and shortcomings, to realize the safe tool change of the earth pressure balance shield machine under the condition of no ground reinforcement in the sand layer construction.

In order to achieve the above object, the present invention provides a construction method for grouting and tool change in the earth pressure balance shield machine cabin in the sand layer, and the construction method includes the following steps:

The first step is to inject bentonite mud into the soil bin:

Inject bentonite mud into the soil bin through the ball valves located at 3 o'clock and 12 o'clock in the soil bin, and the injection amount of bentonite mud is 10% to 15% of the volume of the soil bin;

The second step is to replace the dregs and mud in the soil bin with air:

Turn the screw conveyor to output the muck slurry in the soil bin until the muck mud is completely discharged, that is, the screw conveyor will no longer output the muck mud; during the process of outputting the muck mud, keep the pressure in the soil bin stable at the first set value ;

The third step is to fill the gap under pressure:

The pressure in the soil bin is kept at the first set value, and the gap between the front shield at the incision ring of the cutter head and the soil body is plugged tightly with cotton wool, and the leakage sealing is used for sealing;

The fourth step, backfilling the soil bin:

(1) Connect the sleeve valve tube to the soil silo through the ball valve on the wall of the soil silo. The arrangement of each ball valve and sleeve valve tube is as follows: the 12-point ball valve is injected with cement mortar; the 10-point ball valve is connected to the sleeve valve tube, and the sleeve valve tube Fix it on the lugs at 11 o'clock and 12 o'clock, and inject grout; the ball valve at 2 o'clock is used to check the grouting of the ball valve at 10 o'clock;

(2) Cement mortar injection: fill the cement mortar from the 12 o'clock ball valve into the soil bin; simultaneously open the 3 o'clock and 9 o'clock ball valves to slowly release the air until the cement mortar is discharged; close the 3 o'clock and 9 o'clock ball valves , continue to add cement mortar, and use the 1-point ball valve to slowly release the air; during the process of replacing the air with cement mortar, keep the pressure in the soil bin at the second set value, and stop injecting cement mortar after the cement mortar fills the soil bin. Close the 1-point ball valve; reverse the screw conveyor after a period of time during the cement mortar filling process to prevent the screw conveyor from getting stuck;

(3) Grout injection: after the initial setting of the cement mortar injected into the soil bin, add cement slurry to the soil bin from the ball valve at 10 o'clock; during the grout injection process, open the pressure relief hole of the man gate to slowly release the air in the bin; After the cement slurry flows out of the 2-point ball valve, stop injecting the slurry;

The fifth step, clearing the warehouse and changing the tool:

From the 24th hour after the completion of backfilling the soil silo, judge the solidification strength of the grout in the soil silo through the pressure relief hole of the man gate every 2 hours. For cement slurry, clean the soil bin and do not chisel the opening of the cutter head at this time; ensure the integrity of the cutter head surface and replace the tool from bottom to top. When changing the tool, install the table firmly, disassemble the bolts and self-locking nuts, and remove the old tool , replace with a new knife, and tighten the bolts;

The sixth step, resume excavation:

After all the cutters on the cutter head of the shield machine are replaced, the shield machine resumes tunneling.

Preferably, in the first step, the bentonite slurry is chemical slurry, and the mixing materials are calcium-based bentonite and water, and the volume ratio of calcium-based bentonite to water is 1:3.

Preferably, in the first step, the point is the azimuth pointed by the hour hand on the dial scale of the clock.

Preferably, in the first step, the ball valve is a valve in which the opening and closing member of the ball is driven by the valve stem and rotates around the axis of the ball valve.

Preferably, in the third step, the cutting ring of the cutter head is a ring-shaped structure with a cutting edge located at the frontmost part of the shield machine, which plays the role of excavation and soil retaining.

Preferably, in the third step, the front shield is located at the front of the shield, and is a cylindrical steel structure, inside which is installed a main driving device for supporting the cutter head and a screw conveyor.

Preferably, in the third step, the plugging spirit is a cement mixture for rapid plugging, which has the characteristics of quick setting, early strength, impermeability, micro-expansion, and non-toxic and harmless.

Preferably, in the fourth step (1), the sleeve valve pipe is a one-way closing device that can only discharge slurry to the outside of the pipe and cannot return slurry to the inside of the pipe. It is composed of a PVC outer pipe, a 6-point galvanized grouting inner Tube, rubber sleeve, sealing ring.

Preferably, in the fourth step (1), the mass ratio of the cement mortar is cement:sand:water=1:a:b, wherein: 0.5≤a≤1.5, 1≤b≤2.

Preferably, in the fourth step (1), the mass ratio of the cement slurry is cement:water=1:1.

Preferably, in the fourth step (3), the pressure relief hole of the man gate is a valve that can be opened and closed according to the pressure, and it is arranged on the upper part of the earth bin partition.

Preferably, in the fifth step, if there is water leakage during the tool change process, it is blocked with cotton wool and leak blocking spirit.

Preferably, in the fifth step, the opening of the cutter head is an opening on the cutter head, which is used to realize chip removal of cutting muck.

Preferably, in the fifth step, the self-locking nut is a self-locking, anti-loosening and anti-vibration nut relying on frictional force.

Preferably, in the second step and the third step: said keeping the pressure in the soil bin stable at a first set value, the first set value is 0.06MPa.

Preferably, in the fourth step: maintaining the pressure in the soil bin at a second set value, the second set value is 0.06-0.07 MPa.

Compared with the prior art, the present invention has the following beneficial effects:

The invention aims at the problem of earth pressure balance shield machine filling and changing tools under the condition of no ground reinforcement in the sand layer, and provides a grouting tool change in the earth pressure balance shield machine chamber suitable for the condition of no ground reinforcement in the sand layer Compared with the existing patented technology, the advanced construction method avoids the difficult advanced grouting construction operation, clarifies the grouting construction operation method, prevents the cement mortar in the screw conveyor from hardening and causes equipment damage, and effectively reduces the construction workload. ; The present invention has short construction time, high efficiency and strong safety.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is a schematic diagram of an earth pressure balance shield machine in the process of outputting dregs and mud in an embodiment of the present invention;

Fig. 2 is the schematic diagram of arrangement of ball valve and sleeve valve pipe in the cement mortar replacement step in the embodiment of the present invention;

Fig. 3 is a schematic diagram of the opening position of the cutter head in the embodiment of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

As shown in Figure 1-3, this embodiment provides a construction method for grouting and tool change in the earth pressure balance shield machine chamber in the sand layer, which is used in a tunnel in Guangzhou; the bottom depth of the shield machine cutter head is 14m underground, The ground above the stop position is an intersection. In order to prevent the structure of the cutter head from being damaged due to excessive wear, bursting and jamming of the cutter, which will affect the normal construction work, it is necessary to adopt the construction method of filling the warehouse and changing the tool to ensure the safe and effective construction of the tool change. The specific construction steps are briefly described as follows:

The first step, construction site geological survey:

Determine the stratum distribution from 6m below the bottom of the shield machine cutter head to the upper ground by consulting the geological survey report; investigate the ground conditions on the upper part of the shield machine cutter head (that is, from the 45° oblique line on the bottom surface of the shield machine cutter head to the surface conditions of existing buildings or structures in the upper part of the range), determine whether there are ground reinforcement conditions;

In this embodiment, the strata from 6m below the bottom of the shield machine cutter head to the upper ground are distributed as a clay layer with a thickness of 5m, a sand layer with a thickness of 10.5m, and a plain fill layer with a thickness of 4.5m. The pan is in the sand layer; the permeability coefficient of the clay layer is 1.5m/d, the permeability coefficient of the sand layer is 10m/d; the permeability coefficient of the plain fill layer is 0.4m/d. The upper ground of the shield machine is an intersection without ground reinforcement conditions.

The second step is to determine the tool change method:

It is determined that the shield machine is located in the sand layer and there is no ground reinforcement condition. Under this condition, the shield machine cannot be changed under normal pressure. At the same time, the gas retention capacity of the sand layer is poor, and the tool change under pressure cannot be performed in the sand layer. Therefore, it is determined to adopt the construction method of grouting and tool change in the earth pressure balance shield machine chamber in the sand layer.

The third step is to inject bentonite mud into the soil bin:

Inject bentonite mud into the soil bin through the ball valves located at 3 o'clock and 12 o'clock in the soil bin. The amount of bentonite mud injected is 15% of the volume of the soil bin, that is, 4.5m ³ .

The fourth step is to replace the dregs and mud in the soil bin with air

Turn the screw conveyor to output the muck slurry in the soil bin until the muck mud is completely discharged, that is, the screw conveyor will no longer output the muck mud; during the process of outputting the muck mud, keep the pressure in the soil bin stable at 0.06MPa, and output the dregs The soil mud process is shown in Figure 1.

The fifth step, filling the gap under pressure:

The pressure in the soil bin is kept at 0.06MPa, and the gap between the front shield at the incision ring of the cutter head and the soil body is tightly plugged with cotton wool, and sealed with the leak-stopping spirit.

The sixth step is to backfill the soil bin, specifically:

(1) Connect the sleeve valve tube to the soil silo through the ball valve on the wall of the soil silo. The arrangement of each ball valve and sleeve valve tube is as follows: the 12-point ball valve is injected with cement mortar; the 10-point ball valve is connected to the sleeve valve tube, and the sleeve valve tube Fix it on the lugs at 11 o’clock and 12 o’clock, and inject grout; the ball valve at 2 o’clock is used to check the grouting of the ball valve at 10 o’clock; the arrangement of the ball valve and sleeve valve pipe is shown in Figure 2.

(2) Cement mortar: the ratio a of sand to cement mass in the cement mortar is 0.75, the ratio b of water to cement mass is 1.18, and the cement mortar is injected into the soil bin from the ball valve at 12 o'clock; at the same time Open the 3 o'clock and 9 o'clock ball valves to slowly release the air until the cement mortar is discharged; close the 3 o'clock and 9 o'clock ball valves, continue to add cement mortar, and use the 1 o'clock ball valve to slowly release the air; replace the air with cement mortar , keep the pressure in the soil silo at 0.06MPa. After the cement mortar fills the soil silo, stop injecting cement mortar and close the 1-point ball valve; reverse the screw conveyor at intervals of 20 minutes during the cement mortar filling process to prevent the screw conveyor from getting stuck .

(3) Grout injection: The cement mortar injected into the soil bin will complete the initial setting after 4 hours, and the cement mortar will be injected into the soil bin from the ball valve at 10 o'clock; during the grout injection process, the man gate pressure relief hole will be opened to slowly release the air in the bin ; After the cement slurry flows out of the ball valve at 2 o'clock, stop injecting the slurry.

The seventh step, clearing the warehouse and changing the tool:

From the 24th hour after the backfilling of the soil silo, judge the solidification strength of the grout in the soil silo through the pressure relief hole of the man gate every two hours. After 72 hours of backfilling the soil silo, the slurry in the earth silo will completely solidify; Remove the solidified cement mortar and cement slurry from the top, and clean the soil bin. At this time, do not chisel the opening of the cutterhead; ensure the integrity of the cutterhead surface and replace the cutter from bottom to top. When changing the cutter, install the table firmly, remove the bolts and Self-locking nut, remove the old knife, replace with a new one, tighten the bolt. When the upper cutter was replaced, there was water seepage from the lower cutter. After using cotton wool to block the water seepage gap of the lower cutter, it was sealed with the plugging spirit, and the water-stopping effect was good. During the process of clearing the warehouse and changing the tool, the face of the pocket is stable, and there is no phenomenon of rising water level. The opening of the cutter head is an opening on the cutter head, which is used to realize the chip removal of cutting muck, and its position is shown in Figure 3.

The eighth step, resume excavation:

After all the cutters on the cutter head of the shield tunneling machine have been replaced, the screw conveyor is tested, and the screw conveyor operates normally, and the shield tunneling machine resumes excavation.

The invention aims at the problem of earth pressure balance shield machine filling and changing tools under the condition of no ground reinforcement in the sand layer, and provides a grouting tool change in the earth pressure balance shield machine chamber suitable for the condition of no ground reinforcement in the sand layer Compared with the existing patented technology, this method avoids the difficult advance grouting construction operation, clarifies the grouting construction operation mode, prevents the cement mortar in the screw conveyor from hardening and causes equipment damage, and effectively reduces the construction cost. Amount of work; the invention has short construction time, high efficiency and strong safety.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (10)

1. a kind of construction method of grouting in the earth pressure balance shield machine storehouse of sand layer and changing tool, it is characterized in that, described construction method comprises the steps: The first step is to inject bentonite mud into the soil bin: Inject bentonite mud into the soil bin through the ball valves located at 3 o'clock and 12 o'clock in the soil bin, and the injection amount of bentonite mud is 10% to 15% of the volume of the soil bin; The second step is to replace the dregs and mud in the soil bin with air: Turn the screw conveyor to output the muck slurry in the soil bin until the muck mud is completely discharged, that is, the screw conveyor will no longer output the muck mud; during the process of outputting the muck mud, keep the pressure in the soil bin stable at the first set value ; The third step is to fill the gap under pressure: The pressure in the soil bin is kept at the first set value, and the gap between the front shield at the incision ring of the cutter head and the soil body is plugged tightly with cotton wool, and the leakage sealing is used for sealing; The fourth step, backfilling the soil bin: (1) Connect the sleeve valve tube to the soil silo through the ball valve on the wall of the soil silo. The arrangement of each ball valve and sleeve valve tube is as follows: the 12-point ball valve is injected with cement mortar; the 10-point ball valve is connected to the sleeve valve tube, and the sleeve valve tube Fix it on the lugs at 11 o'clock and 12 o'clock, and inject grout; the ball valve at 2 o'clock is used to check the grouting of the ball valve at 10 o'clock; (2) Cement mortar injection: fill the cement mortar from the 12 o'clock ball valve into the soil bin; simultaneously open the 3 o'clock and 9 o'clock ball valves to slowly release the air until the cement mortar is discharged; close the 3 o'clock and 9 o'clock ball valves , continue to add cement mortar, and use the 1-point ball valve to slowly release the air; during the process of replacing the air with cement mortar, keep the pressure in the soil bin at the second set value, and stop injecting cement mortar after the cement mortar fills the soil bin. Close the 1-point ball valve; reverse the screw conveyor after a period of time during the cement mortar filling process to prevent the screw conveyor from getting stuck; (3) Grout injection: after the initial setting of the cement mortar injected into the soil bin, add cement slurry to the soil bin from the ball valve at 10 o'clock; during the grout injection process, open the pressure relief hole of the man gate to slowly release the air in the bin; After the cement slurry flows out of the 2-point ball valve, stop injecting the slurry; The fifth step, clearing the warehouse and changing the tool: From the 24th hour after the completion of backfilling the soil silo, judge the solidification strength of the grout in the soil silo through the pressure relief hole of the man gate every 2 hours. Mortar and cement slurry, clean the soil bin, do not chisel the opening of the cutter head at this time; ensure the integrity of the cutter head surface and replace the tool from bottom to top. When changing the tool, install the table firmly, disassemble the bolts and self-locking nuts, remove Replace the old knife with a new one and tighten the bolts; The sixth step, resume excavation: After all the cutters on the cutter head of the shield machine are replaced, the shield machine resumes tunneling. 2. the construction method of grouting in the earth pressure balance shield machine chamber of a kind of sand layer according to claim 1, is characterized in that, in the first step, described bentonite mud is chemical mud, and grouting material Calcium-based bentonite and water, the volume ratio of calcium-based bentonite to water is 1:3. 3. the construction method of grouting in the earth pressure balance shield machine chamber of a kind of sand layer according to claim 1, is characterized in that, in the first step: The point is the position pointed by the hour hand on the scale of the clock dial; The ball valve is a valve in which the opening and closing part of the ball is driven by the valve stem and rotates around the axis of the ball valve. 4. the construction method of grouting and tool change in the earth pressure balance shield machine chamber in a kind of sand layer according to claim 1, is characterized in that, in the third step: The cutting ring of the cutter head is a ring structure with a cutting edge at the frontmost part of the shield machine; The front shield is located at the front of the shield, and is a cylindrical steel structure, inside which is installed a main drive device for supporting the cutter head and a screw conveyor. 5. the construction method of grouting tool change in a kind of earth pressure balance shield machine cabin in sand layer according to claim 1, it is characterized in that, in the 4th step (1): The mass ratio of the cement mortar is cement:sand:water=1:a:b, wherein: 0.5≤a≤1.5, 1≤b≤2; The mass mixing ratio of the cement slurry is cement:water=1:1. 6. The construction method of grouting and tool change in the earth pressure balance shield machine cabin in a kind of sand layer according to claim 1, characterized in that, in the fourth step (1), the sleeve valve pipe is a A one-way closing device that can only discharge slurry to the outside of the tube and cannot return slurry to the inside of the tube. It is composed of a PVC outer tube, a 6-point galvanized grouting inner tube, a rubber sleeve, and a sealing ring. 7. the construction method of grouting tool change in the earth pressure balance shield machine cabin in a kind of sand layer according to claim 1, it is characterized in that, in the 4th step (3), described man gate pressure relief hole is The valve that can be opened and closed according to the pressure is arranged on the upper part of the earth bin partition. 8. The construction method of grouting tool change in the earth pressure balance shield machine cabin in a kind of sand layer according to claim 1, it is characterized in that, in the fifth step, if there is water leakage during the tool change process, use cotton wool and Plugging spirit is used for sealing. 9. The construction method of grouting and tool change in the earth pressure balance shield machine chamber in a sand layer according to claim 1, characterized in that, in the fifth step, the opening of the cutter head is an opening on the cutter head , used to realize chip removal of cutting slag; in the fifth step, the self-locking nut is a self-locking, anti-loosening and anti-vibration nut relying on frictional force. 10. The construction method of grouting and tool change in the earth pressure balance shield machine chamber in a sand layer according to claim 1, characterized in that, in the second step and the third step: said maintaining the pressure in the earth chamber Stable at the first set value, the first set value is 0.06MPa; In the fourth step: maintaining the pressure in the soil bin at the second set value, the second set value is 0.06-0.07 MPa.