CN113686914A - Interface effect test simulation method for coastal soft soil subway communication channel freezing method - Google Patents
Interface effect test simulation method for coastal soft soil subway communication channel freezing method Download PDFInfo
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- G01N25/00—Investigating or analyzing materials by the use of thermal means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/16—Investigating or analyzing materials by the use of thermal means by investigating thermal coefficient of expansion
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
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Abstract
A freezing method interface effect test simulation method for a coastal soft soil subway communication channel is characterized by comprising the following three processes: firstly, building; secondly, interface simulation; thirdly, refrigerating and freezing the soil body; fourthly, detecting and researching soil change; scanning and monitoring the geological condition of the soil body (212) of the freeze-thaw model box (210) in a test period by using an IDS ground penetrating radar (304), and mutually verifying the data obtained by the ground penetrating radar and the monitoring data of the temperature measuring system and the strain gauge system.
Description
Technical Field
The invention belongs to the field of subway tunnels, relates to coastal soft soil subway connecting channel freezing method interface effect test simulation, and is suitable for subway connecting channel freezing method construction interface effect research.
Background
In recent years, with the continuous advance of urbanization, the construction of subway tunnels is particularly rapid. The communication channel is used as a channel with communication, drainage and fire prevention functions and also shows a special position in construction. Usually, the connection channel needs to be reinforced before excavation, and common reinforcing methods include a ground reinforcing method, a grouting reinforcing method in a tunnel and a freezing reinforcing method. Freezing consolidation has been widely used as a common method.
The freezing method is a stratum reinforcing method which freezes water in a stratum into ice by an artificial refrigeration technology, changes natural rock soil into artificial frozen soil, forms a frozen soil curtain, isolates underground water and improves the strength and stability of a soil body. Thus, freezing is particularly useful in coastal soft soil formations that are rich in water. The frozen soil forms a cylindrical closed curtain (frozen soil curtain) between two adjacent tunnels, a plurality of interfaces exist between the boundary of the curtain and the surrounding environment, heat exchange is carried out between the frozen soil and the outside at the interface, so that the cold loss is caused, the temperature field change is caused, the boundary frozen soil is melted seriously, the inner water system and the outer water system of the curtain are communicated, the water-resisting property is invalid, and the phenomena of water seepage, sand gushing and the like are caused when the communication channel is excavated. The long-term cold loss can lead to freezing the reason and move backward continuously, influences the whole stability of curtain, and serious person will cause the contact passageway pore wall to collapse, if inside the tunnel is gushed to soil, forms a large amount of losses, will cause the stratum to sink. It can be seen that the interface effect is an important influencing factor in the freezing method construction.
However, the current freezing method model test equipment cannot study the interface effect of freezing method construction, so that the related study on curtain state change caused by the interface effect is less. Therefore, in order to overcome the defect that the interface effect of freezing method construction cannot be researched by the existing freezing method model test equipment, the coastal soft soil subway communication channel freezing method interface effect test simulation system is invented.
Disclosure of Invention
In order to overcome the defect that the interface effect of freezing method construction cannot be researched by the existing freezing method model test equipment, the invention provides a coastal soft soil subway contact channel freezing method interface effect test simulation system and method, which can effectively avoid the defects of the existing test equipment. The invention can simulate the forming and melting process of the frozen soil curtain in the actual subway communication channel freezing method construction, and has the advantages of high reduction degree, wide application range, simple operation and low manufacturing cost.
Technical scheme
A freezing method interface effect test simulation method for a coastal soft soil subway communication channel is characterized by comprising the following three processes:
firstly, building;
secondly, interface simulation;
thirdly, refrigerating and freezing the soil body;
fourthly, detecting and researching soil change;
wherein:
the building step comprises:
1.1 comprises a freezing and thawing model box (210) which is used for placing a soil body (212) to be tested;
1.2 comprises an inlet and outlet hose, an insulating layer, a cold source emitter, a freezing liquid (105), a refrigerator (108), a computer temperature control panel (109) and a freezing liquid flow control panel (110), wherein the hose, the insulating layer, the cold source emitter and the refrigerator (108) form a loop; the cold source emitter comprises a plurality of freezing pipes (103) which are 8 in number and distributed in a regular octagon shape, and water distributors (104) positioned on two sides, wherein the freezing pipes are connected with the water distributors on the two sides;
1.3, a tunnel model pipe is arranged in the center of the central emitter, and the tunnel model pipe and the central emitter are axially arranged in the freeze-thawing model box;
the interface simulation step comprises:
2.1 constructing an interface simulation system, placing a cold source emitter in a freeze-thaw model box, placing a tunnel model tube made of a steel tube sheet (209) in the freeze-thaw model box, and arranging different heat insulation measure layers on different sections of the tube wall of the tunnel model tube, so that: an inner soil body is distributed between the tunnel model pipe and the freezing pipe (103); the outer soil body is distributed between the sandwich structure of the freeze-thaw model box and the freezing pipe (103); in a freeze-thaw model box, its axial: the tunnel model pipe adopts heat insulation measure layers matched with the A, B, C three-step soil body interface simulation system areas with heat insulation measures reduced step by step in A, B, C three different soil body interface simulation system areas; simultaneously:
2.2, four walls of the freeze-thaw model box are designed into a hollow sandwich structure, a bottom plate is solid, a soil body (212) to be detected is placed in the freeze-thaw model box, the bottom of the soil body is directly contacted with the bottom plate, a heat-preservation filling material (211) is arranged between the soil body and the hollow sandwich wall and then contacted, and the upper part of the soil body is directly contacted with air; forming three-order soil interface simulation systems including A ', B' and C 'in an outer soil body area of the freeze-thaw model box, and respectively matching the three different soil interface simulation systems A', B 'and C' by utilizing an open, solid bottom plate and peripheral interlayer structure of the freeze-thaw model box;
the refrigeration and soil body freezing step comprises the following steps:
3.1 the freezing liquid (105) is produced by the refrigerator (108) and enters a loop, and is sent to the cold source emitter through the loop, the computer temperature control panel (109) is used for controlling the temperature of the freezing liquid (105) so as to control the test environment temperature of the refrigeration system, and the freezing liquid flow control panel (110) is used for controlling the operation of the refrigerator;
3.2 freezing liquid (105) is subjected to freezing by each multi-dimensional interface simulation system constructed by cold source emission in vivo and freezing, the soil body 212 in the freezing and thawing model box 210 is frozen, after the soil body 212 is frozen and looped, the arrangement loop of the freezing pipes 103 is taken as a central loop to form a cylindrical frozen soil curtain with a certain thickness, and frozen soil is distributed on the inner side and the outer side of the central loop;
the soil change detection and research steps comprise
4.1, monitoring the displacement strain of the soil body (212) at each measuring point in the freeze-thaw model box (210) in the whole process by using a strain gauge (305) and a plurality of strain gauges (306) distributed on the interface of the soil body in the test process; at the same time
4.2, utilizing a plurality of temperature measuring probes (302) distributed on the interface of the soil body, and carrying out overall process monitoring on the temperature of the soil body (212) of each measuring point in the freeze-thaw model box (210) by a temperature measuring system in the test process;
4.3IDS ground penetrating radar (304), scanning and monitoring the geological condition of the soil body (212) of the freeze-thaw model box (210) in a test period, and mutually verifying the data obtained by the ground penetrating radar and the monitoring data of the temperature measuring system and the strain gauge system.
A coastal soft soil subway communication channel freezing method interface effect test simulation system is characterized by comprising three subsystems: a refrigeration system, an interface simulation system and a soil body detection system;
the refrigerating system comprises an inlet and outlet hose, an insulating layer, a cold source emitter, a freezing liquid (105), a refrigerator (108), a computer temperature control panel (109) and a freezing liquid flow control panel (110), wherein the hose, the insulating layer, the cold source emitter and the refrigerator (108) form a loop, the freezing liquid (105) is produced by the refrigerator (108) and enters the loop, and is sent into the cold source emitter through the loop, and the cold source emitter is arranged in the interface simulation system; furthermore, the cold source emitter comprises a plurality of freezing pipes (103) which are 8 in number and distributed in a regular octagon shape, and water distributors (104) positioned on two sides, wherein the freezing pipes are connected with the water distributors on the two sides; the computer temperature control panel (109) is used for controlling the temperature of the freezing liquid (105) so as to control the test environment temperature of the refrigerating system, and the freezing liquid flow control panel (110) is used for controlling the operation of the refrigerating machine;
the interface simulation system comprises a freeze-thaw model box (210), wherein the four walls of the freeze-thaw model box are of a hollow sandwich structure, a bottom plate is solid, a soil body (212) to be tested is placed in the freeze-thaw model box, the bottom of the soil body is in direct contact with the bottom plate, a heat-preservation filling material 211 is arranged between the soil body and the hollow sandwich wall and then is in contact with the soil body, and the upper part of the soil body is in direct contact with air;
the interface simulation system also comprises a tunnel model pipe made of a steel pipe sheet (209) and a heat insulation measure layer;
the tunnel model pipe is arranged in the center of the central emitter, and the tunnel model pipe and the central emitter are axially arranged in the freeze-thawing model box;
an inner soil body is distributed between the tunnel model pipe and the freezing pipe (103); the outer soil body is distributed between the sandwich structure of the freeze-thaw model box and the freezing pipe (103);
in a freeze-thaw model box, its axial: the tunnel model pipe adopts heat insulation measure layers matched with the A, B, C three-step soil body interface simulation system areas with heat insulation measures reduced step by step in A, B, C three different soil body interface simulation system areas;
in the outer soil body area of the freeze-thaw model box, three-order soil body interface simulation systems A ', B' and C 'are included, and three different soil body interface simulation systems A', B 'and C' are respectively matched by utilizing an open, solid bottom plate and peripheral interlayer structure of the freeze-thaw model box;
the soil body detection system comprises a temperature measurement system, a strain gauge system and an IDS ground penetrating radar (304);
the strain gauge system comprises a strain gauge (305) and a plurality of strain gauges (306) distributed on the interface of the soil body, and the displacement strain of the soil body (212) at each measuring point in the freeze-thaw model box (210) is monitored in the whole process in the test process;
the temperature measurement system (301) comprises a plurality of temperature measurement probes (302) distributed on the interface of the soil body, and the temperature measurement system monitors the temperature of the soil body (212) of each measurement point in the freeze-thaw model box (210) in the whole process in the test process;
an IDS ground penetrating radar (304) scans and monitors the geological condition of the soil body (212) of the freeze-thaw model box (210) in a test period.
Further, the inlet and outlet hoses comprise a freezing liquid loop hose (101) and a freezing liquid outlet hose (106); the heat preservation layer adopts heat preservation sponge (102) for wrapping up in the outside of business turn over hose.
Further, the freezing liquid (105) is saline water which is the same as the actual engineering.
Further defined, a frozen liquid flow control panel (110) is located on the refrigerator (108) for controlling the flow of the frozen liquid.
The coastal soft soil subway communication channel freezing method interface effect test simulation system provided by the invention is suitable for the subway communication channel freezing method construction interface effect research.
The device has the following advantages:
(1) the device has the advantages of capability of simulating the whole process of forming and melting the frozen soil curtain in subway communication channel freezing method construction in reality and high reduction degree. The device designs and manufactures the copper tunnel model tube and designs the refrigerating system as a cold source for a simulation test. The simulation of the formation of the frozen soil curtain and the whole process of ablation in the actual subway communication channel freezing method construction is realized, and the reduction degree of a simulation test is greatly improved.
(2) The device has the advantage that various interfaces can be simulated in the construction of the subway communication channel freezing method. The device freezes the soil body 212 of the freezing and thawing model box 210 through the refrigerating system 1. After the soil body 212 is frozen and looped, the arrangement loops of the freezing pipes 103 are used as a central ring to form a cylindrical frozen soil curtain with a certain thickness, and frozen soil is distributed on the inner side and the outer side of the central ring.
Frozen soil on inner sideDifferent contacts from the tunnel mould tube are formed: the system comprises a wrapping heat insulation foam steel pipe sheet-soil body interface simulation system, a steel pipe sheet-soil body interface simulation system coated with heat insulation coating, and a steel pipe sheet-soil body interface simulation system;
frozen soil on the outer side:the simulation system is in contact with air to form an air-soil interface simulation system, is in contact with the wall of the model box to form a steel pipe sheet-soil interface simulation system containing a heat-insulating filling material interlayer, and is in contact with the bottom of the model box to form a steel pipe sheet-soil interface simulation system. The simulation of various interfaces of the subway communication channel freezing construction is carried out, and the influence of different interfaces on the frozen soil curtain is explored.
(3) The device has the advantages of wide application range and capability of simulating and researching the interface effect of the freezing method construction of the subway communication channel in various soil layer environments. The device takes the soil body 212 filled in the freeze-thaw model box 210 as a research object to research the interface effect of the subway communication channel freezing method construction. By selecting the land 212 with different physical properties, the simulated soil layer environment is different. The interface effect of the subway communication channel freezing method under different soil layer environments can be simulated by utilizing the soil bodies 212 with different physical properties, and the application range is wide.
(4) The device has the advantages of being capable of achieving multi-dimensional monitoring of soil layer properties in the test process, and achieving cross-phase verification of test obtained data and high in accuracy. The device realizes multi-dimensional monitoring of soil layer properties through the temperature measuring system 301, the strain gauge system and the external IDS ground penetrating radar 304. The data obtained by comparison are mutually verified, so that the multidimensional monitoring of the whole test process is realized, and the test accuracy is improved.
(5) The device has the advantage of simple operation.
Drawings
FIG. 1 is a cross-sectional view of a freeze-thaw model box
FIG. 2 front view of a freeze-thaw model box
FIG. 3 is a side view of a freeze-thaw model box
FIG. 4 is a schematic diagram of the arrangement of strain gauges at section A of a freeze-thaw model box
FIG. 5 is a schematic view of arrangement of strain gauges at section B of a freeze-thaw model box
FIG. 6 is a schematic diagram of the arrangement of strain gauges at section C of a freeze-thaw model box
FIG. 7 is a schematic view of arrangement of temperature measuring points at section A of a freeze-thaw model box
FIG. 8 is a schematic view of arrangement of temperature measuring points at section B of a freezing and thawing model box
FIG. 9 is a schematic view of arrangement of temperature measuring points at section C of a freeze-thaw model box
FIG. 10 is a three-dimensional layout of freezing pipes, water separators and freezing liquid return circuit
FIG. 11 is a schematic view of the test system operating frozen soil curtain diffusion
FIG. 12 is a schematic view of simulation interfaces of A section of a freeze-thaw model box
FIG. 13 is a schematic view of simulation interfaces of B section of a freeze-thaw model box
FIG. 14 is a schematic view of simulation interfaces of C section of a freeze-thaw model box
Detailed Description
As shown in fig. 1 to 14, the interface effect test simulation system for the freezing method of the coastal soft soil subway communication channel mainly comprises three systems:
refrigerating system, interface analog system, soil body detecting system.
The refrigerating system comprises a freezing liquid loop hose 101, a heat preservation sponge 102, a freezing pipe 103, a water separator 104, freezing liquid 105, a freezing liquid outgoing hose 106, a hose joint 107, a refrigerator 108, a computer temperature control panel 109 and a freezing liquid flow control panel 110.
The number of the freezing liquid circuit hoses 101 is two. One is fixed on the refrigerator 108, the other is connected with the water separator 104, one end is connected with the water separator 104, the other end is provided with a hose joint 107, and the two hoses form a freezing liquid loop through the joint before use.
Two heat preservation sponges 102 are respectively wrapped on the outer sides of the freezing liquid loop hose 101 and the freezing liquid outgoing hose 106. The refrigeration effect of the refrigeration system 1 is prevented from being influenced by the refrigeration loss generated in the circulating refrigeration process of the frozen liquid 105.
The freezing pipes 103 are distributed in a regular octagon shape with 8 in total and fixed on the water separator 104.
And the water distributors 104 are two in number and are respectively fixed on two sides of the freezing and thawing model box 210. The frozen liquid 105 flowing out of the refrigerator 108 flows into the water separator 21 through the frozen liquid outgoing hose 106. The water separator 21 is hollow, 8 freezing pipes 103 are communicated with the water separator 104, and freezing liquid 105 flows into the freezing pipes 103 to freeze a surrounding soil body 212 to generate a frozen soil curtain. The frozen liquid 105 then flows out of the frozen liquid loop hose 101 from the water separator 104 on the other side, and finally back into the refrigeration system 108.
The freezing liquid 105 is saline water as in the actual process. Flows out of the refrigerator 108, passes through the freezing liquid outward-passage hose 106, the water separator 104, the freezing pipe 103 and the freezing liquid return hose 101, and finally flows back into the refrigerator 108 to complete a freezing cycle. The temperature is controlled by a computer control temperature panel 109 and the flow is controlled by a frozen liquid flow control panel 110.
The freezing liquid goes to the path hose 106, and the total number is two. One is fixed on the refrigerator 108, the other is positioned in the interlayer of the freezing and thawing model box 210, one end is connected with the water separator 104, the other end is provided with a hose joint 107, and the freezing liquid is formed into a freezing liquid path by the two hoses.
The two hose joints 107 are respectively positioned at two sides of the freezing and thawing model box 210 and are connected with the freezing liquid loop hose 101 and the freezing liquid outward-going hose 106.
The refrigerator 108 is connected with the freezing and thawing model box 210 into a whole through a freezing liquid loop hose. The temperature of the freezing liquid 105 is controlled by the computer control panel 20, and the flow rate of the freezing liquid 105 is controlled by the freezing liquid flow rate control panel 110
A computer temperature control panel 109. Located on the refrigerator 108, controls the temperature of the freezing liquid 105.
And a freezing liquid flow control panel 110 which is located on the refrigerator 108 and controls the flow of the freezing liquid.
An interface simulation system, comprising:
wrapped heat insulation foam steel pipe sheet-soil body interface simulation system ATunnel mould tube comprising an externally wrapped insulating foam 207AA section,Of region A Soil 212, in which the heat insulation foam outside the tunnel model pipe contacts the soil 212;
steel pipe sheet-soil body interface simulation system B coated with heat insulation coatingComprising a tunnel-shaped pipe externally provided with a thermal barrier coating 208Section B、Of region B The soil body 212, the heat insulation coating outside the tunnel model pipe in the area is contacted with the soil body 212;
steel pipe sheet-soil body interface simulation system CIncluding tunnel model tubesC section、COf a region The soil body 212, the tunnel model pipe does not have any heat preservation and insulation measures in the area, directly contacts with the soil body 212;
in addition, the solid bottom plate of the steel freezing and thawing model box 210 is in direct contact with the soil body 212, and also formsSteel pipe sheet-soil body Interface simulation system B'；
The soil 212 within the freeze-thaw model box 210 is formed by direct contact with the outside air at the top of the model boxAir conditioner Gas-soil body interface simulation system C'。
The side wall of the freeze-thaw model box 210 is a hollow steel splint, contains heat-insulating filling material 211, and is formed by the contact of the soil body 212 arranged in the model box and the side wall thereofSimulation system A 'containing heat-insulation filling material interlayer steel pipe sheet-soil body interface'。
Wherein, the steel pipe sheet-soil body interface simulation system C and the air-soil body interface simulation system C'For reference, a comparative simulation system was used.
The soil body detection system comprises a temperature measurement system, a strain gauge system and an IDS ground penetrating radar (304);
the strain gauge system comprises a strain gauge (305) and a plurality of strain gauges (306) distributed on the soil body interface, and the displacement strain of soil bodies (212) at each measuring point in the freeze-thaw model box (210) is monitored in the whole process in the test process.
The temperature measurement system (301) comprises a plurality of temperature measurement probes (302) distributed on the interface of the soil body, and the temperature measurement system monitors the temperature of the soil body (212) of each measurement point in the freeze-thaw model box (210) in the whole process in the test process;
an IDS ground penetrating radar (304) scans and monitors the geological condition of the soil body (9) of the freeze-thaw model box (210) in a test period.
Examples
1. The freeze-thaw model box 210 has an outer diameter of 1000mm × 1000mm × 1000mm and a box wall thickness of 51.5mm, is a hollow steel splint, and is filled with a heat-preservation filling material 211 as a heat-preservation interlayer. The two sides of the hollow clamping plate are respectively provided with a freezing liquid loop hose 101 and a freezing liquid outgoing hose 106. The two water distributors 104 are fixed on the two sides of the freeze-thaw model box 210, which are the same as the hose, and eight freezing pipes 103 are arranged and fixed on the water distributors in a regular octagon shape.
2. And designing a tunnel mold pipe made of a copper pipe sheet 209 with the outer diameter of 10cm and the wall thickness of 5 mm. Dividing the material into three sections along the longitudinal direction:
the first section is an A section, heat insulation foam 207 is adopted for heat preservation, and the foam is arranged on the side wall of the tunnel in a gluing mode and used for simulating and wrapping a heat insulation foam steel pipe sheet-soil body interface.
And the section B adopts a heat insulation coating 208 for heat preservation, and the coating is filled on the side wall of the tunnel and is used for simulating the steel pipe sheet-soil body interface coated with the heat insulation coating.
The section C is a copper pipe sheet 12 without heat preservation measures and is used for simulating the simulation of a steel pipe sheet-soil body interface. Wherein the content of the first and second substances,
the section C is a control group, and the tunnel sections A and B are test groups.
3. And placing the tunnel model pipe into the freezing and thawing model box 210 from the tunnel model reserved hole 213. Before filling the soil body 212, the embedding positions of the temperature measuring probe 302 and the strain gauge 306 are determined. Taking the arrangement of the section A as an example, the tunnel model pipe is divided into 5 rings and 4 lines from the inner wall to the outer wall. As shown in fig. 7, the inner wall of the first ring tunnel, the outer wall of the second ring tunnel, and the third ring are dot connection lines of the freezing pipe 103, and the fourth ring and the fifth ring are arranged at equal intervals. And then four vertical lines in the horizontal and vertical direction are led out from the center of the section of the tunnel, and the intersection point of each line and the ring is the arrangement position of the temperature measuring probe 302 and the strain gauge 306. Likewise, the two sections B and C are so positioned.
4. Selecting a soil body 212 with the property which is approximately the same as that of coastal soft soil, filling the freeze-thaw model box 210 with the soil body 212 in layers from bottom to top to a preset embedding position, embedding the temperature measuring probe 302 and the strain gauge 306 in the soil body, and filling a label on the lead 303 when the soil body is embedded so as to facilitate the recording of the test result at the end. After the mold box is closed, a freezing liquid loop hose 101 and a freezing liquid outward-going hose 106 which are fixed on a refrigerator 108 are respectively connected with hose connectors 107 at two sides of a freezing and thawing mold box 210.
5. The connection of the temperature measuring system and the displacement system is realized through a lead 303, and the recording time interval is set to be 1 min. The computer temperature control panel 109 and the freezing liquid flow control panel 110 are opened, the temperature and the flow of the flowing freezing liquid 105 are set, and constant temperature and constant flow freezing is performed. After the soil body 212 is frozen at the contact interface and is circled, the arrangement circle of the freezing pipes 103 is used as a central ring to form a cylindrical frozen soil curtain with a certain thickness, frozen soil is distributed on the inner side and the outer side of the central ring, as shown in fig. 12, 13 and 14 (in order to more vividly depict each frozen soil interface simulation system, the outer frozen soil curtain circular ring is changed into a regular octagon).Inner side Frozen soilContact with different sections of the tunnel model forms: the system comprises a wrapped heat insulation foam steel pipe sheet-soil body interface simulation system A, a heat insulation coating coated steel pipe sheet-soil body interface simulation system B and a steel pipe sheet-soil body interface simulation system C;
and outside frozen soil:simulation system C for forming air-soil interface by contacting with air’And the simulation system is contacted with the wall of the model box to form a steel pipe sheet-soil interface simulation system containing a heat-insulating filling material interlayerA’And contact with the bottom of the model box to form a steel pipe sheet-soil body interface simulation system B’。
6. And (3) monitoring the temperature of the soil body in real time in the test process, and when the temperatures of all the measuring points reach a stable state, closing the refrigerating machine 108, cutting off the freezing liquid 105 to return, and naturally thawing the soil body 212. Meanwhile, in the freezing period, the stabilization period and the unfreezing period of the test, the IDS ground penetrating radar 304 is used for scanning the state of the soil body 212 in the whole process, and the data obtained by the ground penetrating radar can be verified with the monitoring data of the temperature measuring system 301 and the strain gauge system 305.
Claims (1)
1. A freezing method interface effect test simulation method for a coastal soft soil subway communication channel is characterized by comprising the following three processes:
firstly, building;
secondly, interface simulation;
thirdly, refrigerating and freezing the soil body;
fourthly, detecting and researching soil change;
wherein:
the building step comprises:
1.1 comprises a freezing and thawing model box (210) which is used for placing a soil body (212) to be tested;
1.2 comprises an inlet and outlet hose, an insulating layer, a cold source emitter, a freezing liquid (105), a refrigerator (108), a computer temperature control panel (109) and a freezing liquid flow control panel (110), wherein the hose, the insulating layer, the cold source emitter and the refrigerator (108) form a loop; the cold source emitter comprises a plurality of freezing pipes (103) which are 8 in number and distributed in a regular octagon shape, and water distributors (104) positioned on two sides, wherein the freezing pipes are connected with the water distributors on the two sides;
1.3, a tunnel model pipe is arranged in the center of the central emitter, and the tunnel model pipe and the central emitter are axially arranged in the freeze-thawing model box;
the interface simulation step comprises:
2.1 constructing an interface simulation system, placing a cold source emitter in a freeze-thaw model box, placing a tunnel model tube made of a steel tube sheet (209) in the freeze-thaw model box, and arranging different heat insulation measure layers on different sections of the tube wall of the tunnel model tube, so that: an inner soil body is distributed between the tunnel model pipe and the freezing pipe (103); the outer soil body is distributed between the sandwich structure of the freeze-thaw model box and the freezing pipe (103); in a freeze-thaw model box, its axial: the tunnel model pipe adopts heat insulation measure layers matched with the A, B, C three-step soil body interface simulation system areas with heat insulation measures reduced step by step in A, B, C three different soil body interface simulation system areas; simultaneously:
2.2, four walls of the freeze-thaw model box are designed into a hollow sandwich structure, a bottom plate is solid, a soil body (212) to be detected is placed in the freeze-thaw model box, the bottom of the soil body is directly contacted with the bottom plate, a heat-preservation filling material (211) is arranged between the soil body and the hollow sandwich wall and then contacted, and the upper part of the soil body is directly contacted with air; forming three-order soil interface simulation systems including A ', B' and C 'in an outer soil body area of the freeze-thaw model box, and respectively matching the three different soil interface simulation systems A', B 'and C' by utilizing an open, solid bottom plate and peripheral interlayer structure of the freeze-thaw model box;
the refrigeration and soil body freezing step comprises the following steps:
3.1 the freezing liquid (105) is produced by the refrigerator (108) and enters a loop, and is sent to the cold source emitter through the loop, the computer temperature control panel (109) is used for controlling the temperature of the freezing liquid (105) so as to control the test environment temperature of the refrigeration system, and the freezing liquid flow control panel (110) is used for controlling the operation of the refrigerator;
3.2 freezing liquid (105) is subjected to freezing by each multi-dimensional interface simulation system constructed by cold source emission in vivo and freezing, the soil body 212 in the freezing and thawing model box 210 is frozen, after the soil body 212 is frozen and looped, the arrangement loop of the freezing pipes 103 is taken as a central loop to form a cylindrical frozen soil curtain with a certain thickness, and frozen soil is distributed on the inner side and the outer side of the central loop;
the soil change detection and research steps comprise
4.1, monitoring the displacement strain of the soil body (212) at each measuring point in the freeze-thaw model box (210) in the whole process by using a strain gauge (305) and a plurality of strain gauges (306) distributed on the interface of the soil body in the test process; at the same time
4.2, utilizing a plurality of temperature measuring probes (302) distributed on the interface of the soil body, and carrying out overall process monitoring on the temperature of the soil body (212) of each measuring point in the freeze-thaw model box (210) by a temperature measuring system in the test process;
4.3IDS ground penetrating radar (304), scanning and monitoring the geological condition of the soil body (212) of the freeze-thaw model box (210) in a test period, and mutually verifying the data obtained by the ground penetrating radar and the monitoring data of the temperature measuring system and the strain gauge system.
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| CN202110995474.4A CN113686914A (en) | 2021-08-27 | 2021-08-27 | Interface effect test simulation method for coastal soft soil subway communication channel freezing method |
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