A multi-round composite grouting reinforcement construction method for hollowing out and melting settlement of communication channels

Abstract

The invention discloses a multi-round composite grouting reinforcement construction method for hollowing out and melting settlement defects of a communication channel, wherein the method comprises the following steps: preparing a certain proportion of cement slurry and polymer slurry respectively based on the hollowing out and melting settlement defects formed after the communication channel is constructed by freezing method; checking prefabricated grouting holes and judging whether the grouting holes meet the requirements; installing grouting flower pipes in the grouting holes, debugging the grouting equipment, and performing interval grouting of the cement slurry with a good proportion through the grouting equipment; drilling through the original grouting holes by a drilling rig to form a grouting channel for the polymer slurry, and cleaning the environment around the grouting channel; installing a grouting conduit in the opened grouting channel, debugging the grouting equipment, and performing interval grouting of the polymer slurry with a good proportion through the grouting equipment; repeating the above steps, performing multiple rounds of cyclic grouting, until the filling and reinforcement of the communication channel are completed. The invention aims to solve the problems of melting settlement and hollowing out caused by the existing communication channel freezing method construction.

Description

Technical Field

[0001] The invention relates to the technical field of communication channel disease control, and in particular to a multi-round composite grouting reinforcement construction method for communication channel hollowing and melting settlement diseases. Background Art

[0002] As a connecting channel between the up and down tunnels of the subway, it is subject to the specific functions of the subway. It cannot choose the construction site at will like other tunnel systems. It has a phased setting according to the function and safety design, and is affected by many factors such as the surrounding geological conditions, geological structure, ground building safety, and the safety and stability of the main tunnel. At present, the freezing method is generally used for construction before the excavation of the connecting channel, and it has been applied in the construction of subways in many cities. After the excavation is completed, the frozen area of ​​the connecting channel will gradually thaw. The thawing settlement of frozen soil is a very complex and important problem faced in freezing engineering. The thawing of frozen soil will cause the settlement of the stratum. On the one hand, the melting of frozen soil will cause the settlement of the soil body because the volume of ice turns into water. On the other hand, the melting area will be subjected to a certain pressure and the thawed soil will be drained and consolidated, causing the compaction settlement of the coating.

[0003] At present, cement materials are widely used for grouting to fill cavities and reinforce surrounding soil. Cement as a grouting material has the advantages of high strength, good durability, non-toxicity, odorlessness, convenient material source, and low price. However, there are also many problems. When the cement particle size is large, there are more group particles, and the water-cement ratio is large, the stability of the slurry is poor, it is easy to precipitate water and return to concentration, and it cannot be effectively poured into fine cracks; and when hardening, water precipitation is accompanied, the solid phase volume shrinks, and the bonding strength between the hardened stone and the grouting matrix is ​​reduced, forming a new seepage channel.

[0004] Patent document with application number CN201510407722.3 discloses a construction method for reinforcing a frozen communication channel with a grouting freezing pipe to suppress frost heave and thaw settlement. The freezing pipe is used as a grouting pipe, and the grouting freezing pipe consists of a grouting pipe I and a liquid supply pipe II, wherein the grouting pipe I consists of 3-6 sections, a drill bit III is installed at the end of the first section, and a one-way valve IV is arranged on each side of the pipe body; the liquid supply pipe II is made of two steel pipes cross-welded, and a certain amount of cement slurry is infiltrated into the soil to improve the physical and mechanical properties of the soil, which can suppress the influence of frost heave and thaw settlement on the surrounding strata and buildings during the freezing and reinforcement of the communication channel. The construction steps are construction preparation, positioning and opening holes, grouting, installation of liquid supply pipes, installation of refrigeration systems, and maintenance and startup freezing. The patent document with application number CN202111088776.X discloses a method for controlling freezing, frost heaving and thawing settlement of municipal engineering. Cement soil and limestone are transported to the corresponding positions through grouting holes to form a freezing curtain to suppress the freezing, thawing and thawing settlement caused by the freezing method. Infiltrating a certain amount of cement slurry and lime slurry into the soil is beneficial to improving the physical and mechanical properties of the soil. It can suppress the impact of freezing, thawing and thawing settlement caused by artificial freezing methods on surrounding buildings and strata during reinforcement of municipal engineering ends, connecting channels and tunnels. The above two methods both use cement grouting to solve the freezing and thawing settlement problems caused by freezing construction. On the one hand, small voids cannot be grouted, and on the other hand, the permeability problem cannot be completely solved. Therefore, it is urgent to propose a multi-round composite grouting reinforcement construction method for connecting channel de-hollowing and thawing settlement diseases to fundamentally solve the problems of thawing settlement and de-hollowing caused by freezing construction of connecting channels. Summary of the invention

[0005] The main purpose of the present invention is to provide a multi-round composite grouting reinforcement construction method for connecting channel hollowing and thawing settlement diseases, which aims to solve the problems of thawing settlement and hollowing caused by the existing connecting channel freezing construction method.

[0006] To achieve the above object, the present invention provides a multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel, wherein the method comprises:

[0007] S1. Based on the voiding and melting settlement defects formed after the construction of the connecting channel freezing method, cement slurry and polymer slurry are prepared respectively, and the cement slurry and polymer slurry are transported to the construction site according to the designed grouting volume;

[0008] S2, check the prefabricated grouting hole and determine whether the grouting hole meets the requirements. If the grouting hole does not meet the requirements, re-drill the hole and clean the surrounding environment of the grouting hole;

[0009] S3, installing a grouting flower pipe in the grouting hole, debugging the grouting equipment, and performing interval grouting of the well-proportioned cement slurry through the grouting equipment;

[0010] S4, drilling through the original grouting hole by means of a drilling rig to form a grouting channel for the polymer slurry, and cleaning the surrounding environment of the grouting channel;

[0011] S5. After the hole is opened, a grouting conduit is installed in the grouting hole, and the grouting equipment is debugged, and the polymer slurry with a good ratio is grouted at intervals through the grouting equipment;

[0012] S6. Repeat the above steps and perform multiple rounds of grouting until the filling and reinforcement of the communication channel is completed. After the grouting is completed, the grouting hole is sealed.

[0013] In one of the preferred solutions, the polymer slurry adopts a non-water-reactive polymer material, and the non-water-reactive polymer material includes two polymer prepolymer liquid raw materials A and B.

[0014] In one of the preferred embodiments, the cement slurry includes single-liquid cement slurry and CS double-liquid slurry.

[0015] In one of the preferred solutions, the grade strength of the single-liquid cement slurry and the CS double-liquid slurry is P0.42.5; the water-cement ratio in the single-liquid cement slurry is 0.8:1, and the concentration of water glass in the CS double-liquid slurry is 35-40°Be.

[0016] One of the preferred schemes, the specific steps of installing the grouting flower tube in the grouting hole in step S3 are: inserting a φ32 grouting flower tube into the prefabricated grouting hole, the insertion depth of the grouting flower tube being preferably just enough to pass through the connecting channel structural layer; an anti-return device is provided at the upper end of the hole opening of the grouting flower tube.

[0017] One of the preferred schemes, step S3 of grouting the cement slurry with a good ratio by grouting equipment specifically includes: first filling and grouting the gap in the frozen area in the connecting channel, and the filling grouting uses single-liquid cement slurry; after the filling and grouting is completed, the non-frozen area formed by the gradual thawing of the frozen area in the connecting channel is subjected to melt-sinking grouting, and the melt-sinking grouting is grouting from the inside to the outside in sequence, and single-liquid cement slurry is used from the structural layer to the frozen wall 1 meter outward, and CS double-liquid slurry is used from the frozen wall 1 meter away to the peripheral non-frozen area.

[0018] One of the preferred schemes is that the step S2 of judging whether the grouting holes meet the requirements is as follows: collecting the hole distance between adjacent grouting holes, and judging whether the hole distance is greater than a threshold value; if the hole distance between adjacent grouting holes is greater than the threshold value, re-drilling.

[0019] According to one of the preferred embodiments, the debugging of the grouting equipment includes controlling the grouting pressure of the cement slurry and / or polymer slurry during the grouting process of the grouting equipment.

[0020] One of the preferred solutions is that the depth of the grouting channel in step S4 is preferably just enough to pass through the cement slurry grouting consolidation layer; the hole diameter of the grouting channel is 12 mm, and the hole position deviation of the grouting channel is not more than 3 cm.

[0021] In one of the preferred solutions, the diameter of the grouting conduit is 8 mm, and the length of the grouting conduit is not less than the depth of the grouting channel 5 cm.

[0022] In the above technical scheme of the present invention, the multi-round composite grouting reinforcement construction method for the hollowing out and melting settlement defects of the connecting channel includes preparing cement slurry and polymer slurry respectively based on the hollowing out and melting settlement defects formed after the freezing method construction of the connecting channel, and transporting the cement slurry and polymer slurry to the construction site according to the designed grouting volume; checking the prefabricated grouting holes, and judging whether the grouting holes meet the requirements. If the grouting holes do not meet the requirements, re-drilling and cleaning the surrounding environment of the grouting holes; installing grouting flower pipes in the grouting holes , and debug the grouting equipment, and use the grouting equipment to perform interval grouting with a good ratio of cement slurry; drill through the original grouting hole with a drilling rig to form a grouting channel for polymer slurry, and clean the surrounding environment of the grouting channel; after the channel is opened, install a grouting catheter in the grouting channel, and debug the grouting equipment, and use the grouting equipment to perform interval grouting with a good ratio of polymer slurry; repeat the above steps, perform multiple rounds of grouting until the filling and reinforcement of the communication channel is completed, and after the grouting is completed, the grouting hole is blocked. The present invention uses cement slurry and polymer slurry to alternately grout in layers to solve the problems of melting and sinking and emptying caused by the freezing method construction of the communication channel.

[0023] In the present invention, cement grouting materials are used to fill the cavities formed by the thawed frozen body or the melt settlement and voids between the permanent structure and the frozen body; non-water-reactive polymer materials are used to compact and reinforce the cracks and weak layers existing in the rock layer, soil body, structure and soil rock layer by utilizing their high expansion properties, thereby solving the problems of the cement slurry diffusion range being difficult to control, settling after shrinkage and penetration, and at the same time, with the help of the bonding force generated by the non-water-reactive polymer slurry after solidification, the rock blocks on both sides of the crack are bonded, further improving the stability of the entire communication channel.

[0024] In the present invention, cement and polymer grouting are implemented alternately in progressive layers to form an anti-seepage body composed of dense non-water-reactive polymers to wrap the communication channel, thereby achieving the effect of water blocking and anti-seepage, thereby closing the water flow channel and solving the problem of infiltration. At the same time, cement and polymer grouting materials are safe and environmentally friendly and will not affect the surrounding environment.

[0025] In the present invention, the polymer slurry adopts a non-water-reactive polymer material. The material does not need ready-made water to participate in the chemical reaction. After the two-component material is mixed, it reacts by itself and expands, foams and solidifies. It is suitable for both water environment and waterless environment. The foamed solid has a closed-cell structure and strong waterproofness. It can effectively solve the problem of penetration and can also play a reinforcing role. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 It is a schematic flow chart of a multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel according to an embodiment of the present invention;

[0028] Figure 2 It is a structural schematic diagram of the positional relationship between the grouting holes and the communication channel in the multi-round composite grouting reinforcement construction method for the communication channel hollowing and melting settlement disease according to an embodiment of the present invention;

[0029] Figure 3 It is a side view of the positional relationship between the grouting holes and the communication channel in the multi-round composite grouting reinforcement construction method for communication channel hollowing and melting settlement damage in an embodiment of the present invention.

[0030] Description of Figure Numbers:

[0031] 1. Tunnel; 2. Grouting hole; 3. Communication channel.

[0032] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that all directional indications (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0035] In addition, in the present invention, the descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0036] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] See also Figure 1-3 According to one aspect of the present invention, the present invention provides a multi-round composite grouting reinforcement construction method for hollowing and melting and sinking damage of a communication channel, wherein the method comprises:

[0038] S1. Based on the voiding and melting settlement defects formed after the construction of the connecting channel freezing method, a certain proportion of cement slurry and polymer slurry are prepared respectively, and the cement slurry and polymer slurry are transported to the construction site according to the designed grouting volume;

[0039] S2, check the prefabricated grouting hole 2, and determine whether the grouting hole 2 meets the requirements. If the grouting hole 2 does not meet the requirements, re-drill and clean the surrounding environment of the grouting hole 2;

[0040] S3, installing a grouting flower pipe in the grouting hole 2, and debugging the grouting equipment, and performing interval grouting of the well-proportioned cement slurry through the grouting equipment;

[0041] S4, drilling through the original grouting hole 2 by a drilling rig to form a grouting channel for the polymer slurry, and cleaning the environment around the grouting channel;

[0042] S5. After the hole is opened, a grouting conduit is installed in the grouting hole, and the grouting equipment is debugged, and the polymer slurry with a good ratio is grouted at intervals through the grouting equipment;

[0043] S6. Repeat the above steps and perform multiple rounds of grouting until the filling and reinforcement of the subway communication channel 3 is completed. After the grouting is completed, the grouting hole 2 is sealed.

[0044] Specifically, in this embodiment, the polymer slurry adopts a non-water-reactive polymer material, and the non-water-reactive polymer material includes two polymer prepolymer liquid raw materials A and B. The two polymer prepolymer liquid raw materials A and B are respectively placed in different barrels and transported to the site to prevent chemical reactions. After the two polymer prepolymer liquid raw materials A and B are mixed, they react and expand, foam and solidify to form a closed-cell structure of a foamy solid, thereby sealing the water flow channel, having good waterproof performance, and effectively solving the problem of leakage. The high expansion property of the non-water-reactive polymer material is used to compact and reinforce the cracks and weak layers existing in the rock layer, soil, structure and soil rock layer. When the grouting equipment injects a double group of polymer slurry into the diseased area through the grouting conduit, the polymer slurry reacts rapidly after being injected into the cracks, expands in volume, and diffuses along the pores under the action of the expansion pressure, filling the pores and compacting the soil. After solidification, it forms a colloid, fills the entire crack for reinforcement, closes the water flow channel, and solves the problem of penetration. At the same time, with the help of the bonding force generated by the solidification of the polymer slurry, the rock blocks on both sides of the crack are bonded together, thereby improving the stability of the entire connecting channel 3.

[0045] Specifically, in this embodiment, the cement slurry includes single-liquid cement slurry and CS double-liquid slurry; the grade strength of the single-liquid cement slurry and the CS double-liquid slurry is P0.42.5; the water-cement ratio in the single-liquid cement slurry is 0.8:1, and the concentration of water glass in the CS double-liquid slurry is 35-40°Be; the cement slurry is mainly used to fill the voids formed by the thawed frozen body or the melt settlement and voids between the permanent structure and the frozen body.

[0046] Specifically, in the present embodiment, the grouting hole 2 is prefabricated in the step S2, and it is determined whether the grouting hole 2 meets the requirements. If the grouting hole 2 does not meet the requirements, the hole is re-drilled and the surrounding environment of the grouting hole 2 is cleaned; the grouting hole 2 is pre-set on the communication channel 3, and it is necessary to determine whether the grouting hole 2 meets the grouting requirements before grouting, wherein the determination of whether the grouting hole 2 meets the requirements is specifically as follows: collecting the hole distance between adjacent grouting holes 2, and determining whether the hole distance is greater than a threshold value; if the hole distance between adjacent grouting holes 2 is greater than a threshold value, re-drilling is performed. For newly drilled holes, if the hole spacing is less than or reaches the threshold, the prefabricated grouting holes 2 can be directly used; the threshold is determined by the grouting pressure, the range of diffusion of the grouting slurry and the need to strengthen grouting in some areas. When the hole spacing between adjacent grouting holes 2 is too large, that is, when the hole spacing is greater than the preset threshold, the grouting holes 2 need to be denser; cleaning the surrounding environment of the grouting holes 2 is specifically as follows: when grouting starts, open the plugs or bolt caps on the prefabricated grouting holes 2, and use a jackhammer to drill out the soil, cement and other debris filling the prefabricated grouting holes 2 or the newly drilled grouting holes 2.

[0047] Specifically, in the present embodiment, the grouting tube is installed in the grouting hole 2 in step S3 as follows: a φ32 grouting tube is inserted into the prefabricated grouting hole 2, and the insertion depth of the grouting tube is preferably just enough to pass through the structural layer of the communication channel 3; an anti-return device is provided at the upper end of the orifice of the grouting tube; during the entire grouting process, the grouting tube does not need to be pulled out, and the grouting tube is inserted outward for the next grouting. When any grouting hole 2 is grouting, the grouting holes 2 on the side need to be opened to exhaust air, and the grouting holes 2 are grouted at intervals during grouting; The debugging of the grouting equipment includes controlling the grouting pressure of cement slurry and / or polymer slurry during the grouting process of the grouting equipment. The grouting pressure of cement slurry during the grouting process of the grouting equipment is controlled at 0.3MPa-0.5MPa, and the grouting pressure of polymer slurry during the grouting process of the grouting equipment is controlled at 5MPa-7MPa. During the grouting construction process, in order to prevent accidents caused by instantaneous high pressure, a high-pressure relief safety valve should be installed in front of the pump to relieve pressure in special circumstances where over-pressure grouting may occur. After the grouting starts, the pump pressure is observed in real time.

[0048] Specifically, in the present embodiment, the step S3 of grouting the cement slurry with a good proportion by the grouting equipment specifically includes: first, filling and grouting the gap in the frozen area in the connecting channel 3, and the filling and grouting adopts single-liquid cement slurry; after the filling and grouting is completed, the non-frozen area formed by the gradual thawing of the frozen area in the connecting channel 3 is subjected to melt-sinking grouting, and the melt-sinking grouting is sequentially grouted from the inside to the outside, and the single-liquid cement slurry is adopted from the structural layer to the frozen wall 1 meter outward, and the CS double-liquid slurry is adopted from the frozen wall 1 meter away to the peripheral non-frozen area; the filling and grouting is the post-lining filling and grouting within 3-7 days after the freezing of the connecting channel 3 stops, and the reserved grouting pipe is mainly used to fill and grout the gap between the frozen curtain and the permanent structure, and the melt-sinking grouting adopts the natural thawing method, and the grouting pipe reserved between the frozen curtain and the bypass channel lining is used for melt-sinking compensation grouting.

[0049] Specifically, in this embodiment, in step S3, the grouting volume and pressure are used as control standards to determine the end of cement slurry grouting, and the overflow holes and exhaust holes are observed in real time. After the grouting of the cement slurry is completed, a certain period of pressure maintenance is set.

[0050] Specifically, in the present embodiment, in the step S4, the original grouting hole 2 is drilled through by a drilling rig to form a grouting channel for polymer slurry. The depth of the grouting channel is preferably to pass through the cement slurry grouting consolidation layer. An air compressor is used to blow high-pressure air into the borehole through an air nozzle to remove soil debris in the hole. The aperture of the grouting channel is 12 mm, and the hole position deviation of the grouting channel is not greater than 3 cm; the diameter of the grouting conduit is 8 mm, and the length of the grouting conduit is not less than 5 cm of the grouting channel depth; the injection cap is connected to the grouting conduit with a diameter of 8 mm, and the polymer slurry is grouted by the grouting equipment. The grouting equipment for grouting the polymer slurry is an integrated intelligent double-slurry precision mixing grouting equipment. During the grouting process, the grouting pressure of the polymer slurry is controlled at 5 MPa-7 MPa, and grouting is performed layer by layer from bottom to top. 2. From left to right, adopt the method of skip-hole interval grouting, first inject the alternate holes, and then realize the grouting of polymer slurry in the order of injecting other holes, adopt progressive layered alternating grouting, and determine the end of polymer slurry grouting by setting the grouting amount and pressure of the grouting equipment in advance as the control standard. After the first round of cement slurry and polymer slurry grouting of each grouting hole 2 is completed, multiple rounds of grouting of cement slurry and polymer slurry are carried out until the filling and reinforcement of the entire communication channel 3 are completed. After the grouting is completed, the grouting cap is removed, and each grouting hole 2 of the communication channel 3 is sealed with double-fast cement, and plugged or bolted; the judgment of the end of grouting of the entire communication channel 3 is specifically as follows: during multiple rounds of grouting, the overflow hole and the exhaust hole are observed in real time, and the grouting can be stopped when slurry appears; or when leakage and bulge are found in the surrounding soil and structure, the grouting can be stopped. The stiffness bearing capacity of cement grouting materials is used to implement melting settlement and void filling reinforcement. The high expansion property of polymer grouting materials is used to solve the problems of difficult-to-control diffusion range of cement grouting and settlement after shrinkage. Through progressive multi-round grouting of cement slurry and polymer slurry, a layer of impermeable body composed of dense non-water-reactive polymer can be formed to wrap the connecting channel 3, thereby achieving the effect of water blocking and anti-seepage.

[0051] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage in a communication channel, characterized in that: The method comprises: S1. Based on the voiding and melting settlement defects formed after the construction of the connecting channel freezing method, cement slurry and polymer slurry are prepared respectively, and the cement slurry and polymer slurry are transported to the construction site according to the designed grouting volume; the polymer slurry adopts non-water-reactive polymer materials, and the non-water-reactive polymer materials include two polymer prepolymer liquid raw materials A and B; the cement slurry includes single-liquid cement slurry and CS double-liquid slurry; S2, check the prefabricated grouting hole and determine whether the grouting hole meets the requirements. If the grouting hole does not meet the requirements, re-drill the hole and clean the surrounding environment of the grouting hole; S3, installing a grouting flower pipe in the grouting hole, and debugging the grouting equipment, and performing interval grouting with a well-proportioned cement slurry through the grouting equipment; the step S3 of performing grouting with a well-proportioned cement slurry through the grouting equipment specifically comprises: first filling and grouting the gap in the frozen area in the communication channel, and the filling and grouting adopts a single-liquid cement slurry; after the filling and grouting is completed, performing melt-sinking grouting on the non-frozen area formed by the gradual thawing of the frozen area in the communication channel, and the melt-sinking grouting is grouting from the inside to the outside in sequence, and a single-liquid cement slurry is used from the structural layer to the frozen wall 1 meter outward, and a CS double-liquid slurry is used from the frozen wall 1 meter away to the peripheral non-frozen area; S4, drilling through the original grouting hole by means of a drilling rig to form a grouting channel for the polymer slurry, and cleaning the surrounding environment of the grouting channel; S5. After the hole is opened, a grouting conduit is installed in the grouting hole, and the grouting equipment is debugged, and the polymer slurry with a good ratio is grouted at intervals through the grouting equipment; S6, repeat the above steps, and perform grouting of polymer slurry through grouting equipment. The grouting equipment for grouting polymer slurry is an integrated intelligent double-slurry precision mixed grouting equipment. The grouting pressure of polymer slurry is controlled at 5MPa-7MPa during the grouting process. Grouting is performed layer by layer from bottom to top. For each layer of grouting holes, a skip hole interval grouting method is adopted in the order from left to right. The interlaced holes are injected first, and then the other holes are injected to achieve the grouting of polymer slurry. Progressive layered alternating grouting is adopted, and the grouting amount and pressure are set in advance for the grouting equipment as the control standard to achieve When the polymer slurry grouting is completed, after the first round of cement slurry and polymer slurry grouting is completed for each grouting hole, multiple rounds of cement slurry and polymer slurry grouting are carried out until the filling and reinforcement of the entire communication channel is completed. After the grouting is completed, the grouting cap is removed, and each grouting hole of the communication channel is sealed with double-fast cement, and plugged or bolted. Among them, the judgment of the completion of grouting of the entire communication channel is specifically as follows: during multiple rounds of grouting, the overflow holes and exhaust holes are observed in real time, and the grouting can be stopped when slurry appears, or when leakage and bulge are found in the surrounding soil and structure, the grouting can be stopped.

2. A multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel according to claim 1, characterized in that: The grade strength of the single-liquid cement slurry and the CS double-liquid slurry is P0.42.5; the water-cement ratio in the single-liquid cement slurry is 0.8:1, and the concentration of water glass in the CS double-liquid slurry is 35-40°Be.

3. The multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel according to claim 1 is characterized in that: The specific steps of installing the grouting tube in the grouting hole in step S3 are as follows: inserting a φ32 grouting tube into the prefabricated grouting hole, the insertion depth of the grouting tube being preferably just enough to pass through the connecting channel structure layer; an anti-return device is provided at the upper end of the hole of the grouting tube.

4. The multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel according to claim 1 is characterized in that: In step S2, judging whether the grouting holes meet the requirements is specifically as follows: collecting the hole distance between adjacent grouting holes, and judging whether the hole distance is greater than a threshold; if the hole distance between adjacent grouting holes is greater than the threshold, re-drilling.

5. The multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel according to claim 1 is characterized in that: The debugging of the grouting equipment includes controlling the grouting pressure of the cement slurry and / or polymer slurry during the grouting process of the grouting equipment.

6. The multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel according to claim 1 is characterized in that: The depth of the grouting channel in step S4 is preferably just enough to pass through the cement slurry grouting consolidation layer; the hole diameter of the grouting channel is 12 mm, and the hole position deviation of the grouting channel is not greater than 3 cm.

7. A multi-round composite grouting reinforcement construction method for hollowing out and melting and sinking damage of a communication channel according to claim 6, characterized in that: The diameter of the grouting conduit is 8 mm, and the length of the grouting conduit is not less than the depth of the grouting channel 5 cm.

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