The freezing system of shield drive end unit
Technical field
The utility model belongs to shield tunnel reinforcement technique field, is related to exchanging shield ventral brush technology, specially shield tail
The freezing system and exchanging shield ventral brush method in portion.
Background technology
Shield tunnel is just locating the rapid development stage in China, and extensive shield tunnel construction faces many problems, wherein shield
Structure machine is being passed through over long distances rich in water sandy soil or when pebble layer, and shield tail brush is easy to wear, or even is destroyed and caused to leak, therefore
Need to change the shield tail brush for losing sealing function.
One of the technical issues of exchanging shield ventral brush most critical is carried out in soil layer is exactly the waterstop sealing processing to shield tail soil layer,
When construct stratum complicated condition when, this engineering difficulty bigger.Currently used method has chemical consolidation, brine manual pipe jacking
It reinforces and liquid nitrogen manual pipe jacking is reinforced, the wherein liquid nitrogen freezing duration is shorter, and freezing efficiency is reliable, and the liquid nitrogen circulatory system is also opposite
Simply.When using sealing is freezed, it can be divided into prefabricated section of jurisdiction of freezing by the difference of freezing pipe arrangement mode and freeze sealing and section of jurisdiction
Sealing is freezed in upper directly punching, the former the problem of be that the special section of jurisdiction with freezing pipe needs in addition to make, in face of burst
Replacement shield tail brush situation when, ventral brush cannot be carried out immediately and more changed jobs, need the prediction scheme for carrying out exchanging shield ventral brush in advance, for
It speedily carries out rescue work and the higher engineering of construction period does not have practicability.And directly punching freezes sealing and can cope with sudden accident on section of jurisdiction,
It is various to punch flexible form, can be adjusted according to on-site actual situations, main problem, which is freezing hole, to cause forever section of jurisdiction
Long property damage, and the continuity of freezing curtain and uniformity cannot be effectively ensured.
Utility model content
The technical issues of solution:In order to overcome the deficiencies of existing technologies, shield tail can quickly and efficiently be replaced by obtaining one kind
Brush without other punching, blocks drilling, and does not influence section of jurisdiction durability, has no adverse effect to shield tunnel construction stability, this
Utility model provides the freezing system of shield drive end unit.
Technical solution:The freezing system of shield drive end unit, the system comprises liquid nitrogen pipeline and freezing pipe, liquid nitrogen pipelines point
For for nitrogen main pipe and circuit main pipe, respectively with the liquid nitrogen import of freezing pipe and liquid nitrogen outlet;Liquid nitrogen pipeline is set to shield shell
In vivo, freezing pipe is set to shield case inside or outside, and shield tail brush is equipped on the downside of shield shell.
Inbuilt liquid nitrogen pipeline uses arc hollow heat-insulated pipe in the shield shell.
Preferably, freezing pipe is set to shield case inside or outside, including congelation face and adiabatic face, with shield shell
Between by adiabatic face be connected.
Preferably, the section of the freezing pipe is arc, circle or rectangle.It is 50mm to freeze tube section bottom side length degree, high
Degree is 30mm.
Preferably, the section of the freezing pipe be arc, freezing pipe by looped sections be distributed, length be segmented spacing according to
Shield machine diameter is selected.The freezing pipe material is Q345 steel.
The exchanging shield ventral brush method of shield machine described above, includes the following steps:
A, stop shield driving, determine and replace shield tail brush;
B, nitrogen supply unit is marched into the arena, and is connected liquid nitrogen import and liquid nitrogen outlet, is made liquid nitrogen in liquid nitrogen pipeline by liquid nitrogen distributor
It is recycled, makes shield tail freezing soil, form the freezing curtain of sealing on rear side of shield tail brush;
C, after the completion of whole exchanging shield ventral brush, using freezing pipe as defrosting pipeline, forced thaw is carried out;
D, when Frozen Soil Cylinder loses the power that holds around to shield shell, and the soil body and shield are calculated to obtain according to thermometer hole measured temperature
When the temperature of structure shell contact position is in 0 DEG C or more, shield continues to promote.
Advantageous effect:(1) freezing system of shield drive end unit described in the utility model can fast and efficiently realize shield
Drive end unit soil layer freezes, and without in addition being punched on section of jurisdiction, blocking drilling, extends the durability of section of jurisdiction;(2) the utility model
The exchanging shield ventral brush method simple operation, short time limit have no adverse effect to shield tunnel stability.
Description of the drawings
Fig. 1 is that freezing pipe is set to shield hull outside structural schematic diagram, and wherein a is liquid nitrogen inlet side schematic diagram, and b is liquid
Nitrogen exports side schematic diagram;
Fig. 2 is that freezing pipe is set to shield case inside structural schematic diagram;
Fig. 3 is freezing pipe sectional view, wherein a is arc section freezing pipe, and b is circular cross-section freezing pipe, and c cuts for rectangle
Face freezing pipe;
Fig. 4 is liquid nitrogen pipeline schematic cross-section;
Fig. 5 is liquid nitrogen pipeline and freezing pipe joint face schematic diagram;
Fig. 6 is freezing pipe looped sections distribution map;
Fig. 7 is thermometer hole layout drawing on the inside of shield tail;
Fig. 8 is thermometer hole layout drawing on the outside of shield tail;
Wherein, 1- shields shell, 2- is for nitrogen main pipe, 3- freezing pipes, 4- shield tail brushes, the circuits 5- main pipe, 6- liquid nitrogen imports, 7-
Liquid nitrogen exports, the thermal insulation faces 8-, the congelation faces 9-, the sections of jurisdiction 10-, E1~E14- thermometer holes.
Specific implementation mode
Following embodiment further illustrates the content of the utility model, but should not be construed as a limitation of the present invention.
Without departing substantially from the spirit of the present invention and essence, to made by the utility model method, step or condition modification and
It replaces, belongs to the scope of the utility model.Unless otherwise specified, technological means used in embodiment is people in the art
Conventional means known to member.
Embodiment 1
As shown in Figure 1, the freezing system of shield drive end unit, the system comprises liquid nitrogen pipeline and freezing pipe 3, liquid nitrogen pipelines
It is divided into for nitrogen main pipe 2 and circuit main pipe 5, the liquid nitrogen import 6 with freezing pipe 3 and liquid nitrogen outlet 7 respectively is connect.Liquid nitrogen pipeline is set to
In shield shell 1, freezing pipe 3 is set to 1 outside of shield shell, and 1 downside of shield shell is equipped with shield tail brush 4.
Inbuilt liquid nitrogen pipeline 2 uses arc hollow heat-insulated pipe in the shield tail shell 1.
As shown in Figure 1, freezing pipe 3 is set to 1 outside of shield shell, including congelation face 9 and adiabatic face 8, with shield shell
It is connected by adiabatic face 8 between body 1.
As shown in figure 3, the section of the freezing pipe 3 is arc, 3 section bottom edge length of freezing pipe is 50mm, is highly
30mm。
As shown in figure 4, the section of the liquid nitrogen pipeline is arc.
As shown in figure 5, the liquid nitrogen import 6 and liquid nitrogen outlet 7 are distributed in the both sides of freezing pipe 3.
As shown in fig. 6, freezing pipe 3 is distributed by looped sections, length is selected according to shield machine diameter with segmentation spacing.
The freezing pipe material is Q345 steel.
The exchanging shield ventral brush method of shield machine, includes the following steps:
A, stop shield driving, determine and replace shield tail brush 4;
B, nitrogen supply unit is marched into the arena, and connection liquid nitrogen import 6 and liquid nitrogen outlet 7 make liquid in liquid nitrogen pipeline by liquid nitrogen distributor
Nitrogen is recycled, and shield tail freezing soil is made, and the freezing curtain of sealing is formed in 4 rear side of shield tail brush;
C, after the completion of whole shield tail brushes 4 are replaced, using freezing pipe 3 as defrosting pipeline, forced thaw is carried out;
D, when Frozen Soil Cylinder loses the power that holds around to shield shell 1, and according to thermometer hole measured temperature calculate the soil body with
When the temperature of 1 contact position of shield shell is in 0 DEG C or more, shield continues to promote.
Embodiment 2
Shield is carried out to following engineering using the freezing system and exchanging shield ventral brush method of shield drive end unit described in embodiment 1
Ventral brush is replaced:
The stratum that Nanjing Highway Tunnel Construction mainly passes through is very soft sill clay, silty clay folder flour sand, powder
Fine sand layer, Extra-fine sand, gravelly sand, boulder and cobble, siltstone etc., geological conditions is extremely complex along running tunnel, the tunnel bottom soil body
For two water-bearing with high pressure of gravelly sand and cobble, replacing, the swiped through journey risk of shield tail is larger therefore pre-buried by shield tail portion
Freeze pipe device and carry out frozen construction, construction procedure is as follows:
(1) stop shield driving, determine and replace shield tail brush 4, nitrogen supply unit is marched into the arena, connection liquid nitrogen import 6 and liquid nitrogen outlet
7, so that liquid nitrogen in liquid nitrogen pipeline is recycled by liquid nitrogen distributor.The temperature of liquid nitrogen storage tank outlet is controlled -190 DEG C~-170
DEG C, pressure control is advisable in 0.05MPa~0.10MPa, reaches the control of 3 inlet temperature of freezing pipe at -170 DEG C~-150 DEG C, freezes
The control of 3 outlet temperature of pipe is tied at -60 DEG C, pressure control is advisable in 0.05MPa~0.1MPa, and the cut-off on liquid nitrogen storage tank can be used
Valve carries out pressure adjusting, is adjusted into trip temperature with heat sink in every group of circuit.Since liquid nitrogen temperature is extremely low, pipe inside and outside temperature difference compared with
Greatly, scattering and disappearing for cold is easy tod produce, therefore heat-insulated processing must be made to pipeline inner wall.Circuit main pipe does not set heat preservation, after liquid nitrogen gasification
It is directly discharged to outside tunnel in air.
(2) since the tunnel bottom soil body is two water-bearing with high pressure of gravelly sand and cobble, to ensure that different water cut layer freezes
Wall development speed and thickness, set 4 groups of 8 thermometer holes altogether, i.e. E1~E8 monitors frozen temperature field, judges exchanging shield ventral brush opportunity.
It is farinose argillic horizon that wherein E1, E2, which correspond to the soil body,;It is fine sand layer that E3, E4, which correspond to the soil body,;It is gravel layer that E5, E6, which correspond to the soil body,;
It is boulder bed that E7, E8, which correspond to the soil body,.6 temperature measuring points, i.e. E9~E14 are laid on the outside of shield tail in thermometer hole, measuring point spacing is
300mm, hole depth 1.8m, shield tail inside thermometer hole monitor case temperature, hole depth 0.64m;Two thermometer holes and 3 water of freezing pipe in section of jurisdiction
Flat spacing is 500mm and 800mm;Specific Kong Weijian Fig. 7 and Fig. 8.Thermometer hole uses 76 × 5 seamless stainless steels of φ of bottom end seal
Pipe is directly squeezed into.
(3) replacement of shield tail brush 4 freezes acceptance condition and is:Liquid nitrogen freezing time >=10 day, liquid nitrogen freezing effect reach design
It is required that;Speculate that artesian aquifer range frost wall effective thickness reaches 1.8 meters of design requirement according to thermometer hole thermometric, frost wall has
Effect frozen soil mean temperature will reach -20 DEG C and less;Thermometer hole temperature reaches 0 DEG C or less;Emergency preplan of constructing is perfect, and has
Operability;Before shield tail brush 4 is replaced, survey peep hole, anhydrous outflow are pried into four water-bearing layers of shield crossing.
(4) after confirming that three shield tail brushes can all expose, under the protection of Frozen Soil Cylinder, block-by-block removes section of jurisdiction 10.
(5) after section of jurisdiction 10 is removed, the first and second bolt installation shield tail brush 4 is removed, cuts off the welding installation of third road
Shield tail brush 4.The first and second bolt hole of cleaning, cleaning bolt after the completion of shield tail brush 4 is removed.When dismounting from outside to inside, from top to bottom
It removes, takes out the shield tail brush 4 of damage one by one.It scrapes to the place for cutting off out-of-flatness after the old shield tail brush in third road 4 is cut off
Grinding process, so that it is guaranteed that there is no installation out-of-flatness phenomenons when new shield tail brush 4 is installed.
(6) it after the completion of region shield tail brush 4 all installation, welding is removed in section of jurisdiction 10, carries out shield tail grease and smears operation, apply
Fat of putting the oil applies shield tail grease using WR90 type hands.It smears after layered pushes wire brush aside and inserts grease, pay attention to the pressure in grease storehouse
Power situation of change, when grease storehouse, oil pressure reaches 10bar and thinks that shield tail brush 4 reaches design requirement.All installation is complete for domain section of jurisdiction 10
Afterwards, tail seal grease of shield is pumped manually with shield tail grease pump, uncompacted shield tail brush groove and shield tail brush 4 are smeared in filling.
(7) it after the completion of shield tail brush 4 is replaced, needs to carry out forced thaw to frozen soil body, makes shield tail ambient envelope frozen soil body solution
Freeze to ensure that shield continues to promote as early as possible.Directly using step freezing pipe 3 pre-buried on rear side of shield tail steel plate as defrosting pipeline,
It is 0.75m that freezing zone, which is disposed about volume,3Electrical heating hot water circuit case, utilizes 0.5m3Water circulating pump is by 60 DEG C or more in water tank
Hot water circuit is in coil pipe, to achieve the purpose that forced thaw.
(8) according to thermometer hole measured temperature calculate the temperature of the soil body and shield tail shell contact position be in 0 DEG C or more when, shield
Structure can promote again.