Soft soil underground pipeline and pipe gallery slab staggering lifting repairing method

Abstract

The invention discloses a method for lifting and repairing a pipeline and a pipe gallery slab staggering under soft soil, and aims to meet the requirement of grouting pressure design in a slab staggering differential settlement repairing project of an underground large-diameter pipeline and a small-section pipe gallery and improve the grouting repairing effect. According to the method, a mechanical model is established based on a mechanical mechanism existing in a staggered slab pipe joint and a surrounding soil body, and the grouting pressure range of grout is determined; based on the grouting pressure range, a theoretical model of settlement deformation of the soft soil layer below the pipe joint after grouting and compression deformation after solidification of the high polymer grout is established; calculating the slurry height required for lifting the error table pipe joint to a certain height per linear meter; and finally, lifting and repairing of the slab staggering pipe gallery are carried out by adopting a method that a bag is arranged below the pipe joint, high polymer polyurethane is injected inwards for lifting and repairing, and lightweight concrete is filled outwards for reinforcement, so that grouting lifting and repairing of the slab staggering pipe joint in the soft soil area under the condition that the underground pipeline and the underlying foundation soil of the pipe gallery bear safely are achieved. The construction is fast, the economic benefit is high, and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of maintenance and repair of underground structure pipelines and pipe corridors, and relates to the repair technology for the disease of staggered joints of underground pipelines and pipe corridors. Specifically, it relates to a method for repairing the staggered joints of soft soil underground pipelines and pipe corridors by lifting. Background Technique

[0002] With the modernization construction and development of cities, in order to reduce the maintenance costs of various municipal pipelines, improve the integrity of the overall layout of urban projects, and extend the service life of pipelines, the construction scale of urban integrated pipe corridors continues to increase. The underground pipe network is also an important facility for municipal construction and is the basic project for maintaining the normal operation of cities, generally used for sewage discharge, flood prevention, etc. Soft soil strata are a common geological environment, widely distributed in areas such as the Yangtze River Delta and the Pearl River Delta. Soft soil has the characteristics of large void ratio, high natural water content, high compressibility, low strength, small permeability, and high sensitivity. These characteristics cause the underground pipelines and pipe corridors to produce uneven deformation due to the post-construction differential settlement of the soft soil foundation, bringing challenges to the subsequent operation and maintenance.

[0003] Among the operation diseases of pipelines and pipe corridors in soft soil areas, staggered joints are one of the common engineering diseases. The staggered joint parts of pipelines mainly appear at the joints, and the staggered joints of pipe corridors generally occur at the construction joints of pipe corridors. The main reason is that the construction joints of pipe corridors and the joints of pipelines are relatively weak, and coupled with the uneven settlement in soft soil areas, they are displaced under the action of shear stress. When the joints (construction joints) on both sides are displaced simultaneously, differential settlement occurs at both ends of the pipe section at this time, and the pipe section has an overall staggered joint; when a staggered joint appears at one end of the joint (construction joint), the pipe section is inclined and staggered due to local differential settlement. These two types of staggered joint diseases are relatively common in the operation of pipe corridors in soft soil areas. For underground buried pipes, overall staggered joints are common in flat-ended pipes, and inclined staggered joints are common in socket-and-spigot pipes. After the occurrence of staggered joints, it may cause leakage in the pipe corridor and pipelines, resulting in the inability of the pipelines in the pipe corridor to operate normally, and the sewage in the underground pipelines leaks, seriously affecting the lives of the surrounding people. As the pipelines of urban lifelines and the pipe corridors as the pipe accommodation structures need to have high safety and durability. Therefore, the design and development of the technology for treating diseases of underground pipelines and pipe corridors is of great significance for ensuring their operation safety.

[0004] At present, in actual engineering, the trial-and-error method is mostly used to select the grouting pressure for the grouting and lifting repair of the offset of underground structures. There is no clear basis for the selection of the grouting pressure range. It mainly relies on experience to determine a certain value or a certain range, lacking theoretical guidance. As a result, the safe construction conditions for grouting and lifting cannot be guaranteed, nor can the repair effect of grouting and lifting be ensured. In the traditional method of grouting and lifting to repair the offset of underground structures, the grouts selected include ordinary cement grout, water glass, etc. However, these materials have a long curing time and are prone to flow and diffusion in the soil, resulting in serious loss of grout and inability to expand. Therefore, the amount of grout used for cement grouting repair is extremely large, the repair effect is not significant, and the construction period is long, and the use effect of the pipe gallery after repair cannot be guaranteed. Compared with traditional materials, the high-polymer grouting in the lifting and repair expands rapidly in volume and solidifies after a chemical reaction, achieving the purpose of strengthening the foundation, stabilizing and evenly lifting the pipe gallery. Moreover, the high-elastic durability after curing ensures the normal operation of the subsequent pipe gallery. However, in soft soil strata, due to its high permeability and high water content, the grout diffuses severely in the strata after grouting, and the strata settlement and deformation under the pipe gallery are serious, resulting in a large amount of grout used, high repair costs, extremely low grouting efficiency, and unsatisfactory lifting effect. Summary of the Invention

[0005] Object of the Invention: The technical problem to be solved by the present invention is to provide a repair method for the grouting and lifting of the offset of soft soil underground pipelines and pipe galleries in view of the deficiencies of the prior art, to achieve the grouting and lifting repair under the safe bearing conditions of the offset underground pipelines and pipe galleries, improve the grouting technology efficiency and the grouting and lifting effect, and further guide the engineering practice of grouting and lifting to repair the differential settlement of underground pipelines and pipe galleries.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for lifting and repairing the offset of soft soil underground pipelines and pipe galleries, comprising the following steps:

[0008] S1: Establish a mechanical model of the pipe section and the surrounding soil during the lifting process;

[0009] S2: Based on the mechanical model described in step S1, determine the required grouting pressure range when grouting and repairing the offset pipeline and pipe gallery under the pipe section;

[0010] S3: Based on the grouting pressure range in step S2, establish a calculation model for the settlement and deformation of the soil layer under the pipe section and the compression deformation of the high-polymer polyurethane after grouting and the expansion and curing of the grout;

[0011] S4: Based on the calculation model in step S3, obtain the required grout height per linear meter when the offset pipe section is lifted;

[0012] S5: Place the bladder bag under the pipe section, inject high-polymer polyurethane into the bladder bag for lifting and repair, and fill lightweight concrete outside the bladder bag for reinforcement to lift and repair the stepped pipe gallery.

[0013] Specifically, in step S1, the mechanical model of the pipe section and the surrounding soil during the lifting process is established through the following steps:

[0014] S1-1: Determine the load of the overlying soft soil acting on the top surface of the pipe section during the pipe section lifting process :

[0015] S1-2: Determine the self-weight load P of the pipe section acting on the underlying soil layer g ;

[0016] S1-3: Determine the ultimate bearing capacity Q of the foundation of the underlying soil layer of the pipe section u .

[0017] Furthermore, in step S1-1, for a pipe with a circular cross-section in the shape of a cylinder, the load of the overlying soft soil acting on the top surface of the pipe section during the pipe section lifting process is calculated by formula (1):

[0018] (1);

[0019] For a linear pipe gallery with a rectangular cross-section, the load of the overlying soft soil acting on the top surface of the pipe section during its lifting process is calculated by formula (2):

[0020] (2);

[0021] where γ is the effective unit weight of the soil, kg / m³;

[0022] H is the burial depth of the pipe or pipe gallery, m;

[0023] D is the pipe diameter or the width of the pipe gallery, m;

[0024] f is the friction coefficient, which is calculated by the following formula (3):

[0025] (3);

[0026] where φ is the angle of internal friction of the soil, °.

[0027] Furthermore, in step S1-2, the self-weight load P of the pipe section acting on the underlying soil layer g is calculated by the following formula (4):

[0028] (4);

[0029] where ρ is the density of the pipe joint material, kg / m 3 ;

[0030] V is the volume of the pipe joint, m 3 ;

[0031] g is the acceleration due to gravity, m / s 2 ;

[0032] S is the effective cross-sectional area of the pipe joint, m 2 .

[0033] Furthermore, in step S1-3, the ultimate bearing capacity Q of the subsoil under the pipe joint u is calculated by the following formula (5):

[0034] (5);

[0035] In the formula, N q、 N c、 N γ is the ultimate bearing capacity coefficient,

[0036] wherein, N q is calculated by formula (6):

[0037] (6);

[0038] N c is calculated by formula (7):

[0039] (7);

[0040] N γ is calculated by formula (8):

[0041] (8);

[0042] φ is the angle of internal friction of the soil, °;

[0043] c is the cohesion of the soil, kPa;

[0044] γ is the effective unit weight of the soil, kN / m³;

[0045] D is the diameter of the pipe or the width of the pipe gallery, m;

[0046] H is the buried depth of the pipe joint, m.

[0047] Specifically, in step S2, the required grouting pressure range P m when grouting to repair the stepped pipeline gallery under the pipe joint is determined by the following formula (9):

[0048] Q u -Ps -P g ≤P m ≤Q u (9);

[0049] Wherein, Q u is the ultimate bearing capacity of the foundation of the soil layer under the pipe section;

[0050] P g is the self-weight load of the pipe section, kPa;

[0051] is the soil resistance for uplifting the pipe section, kPa;

[0052] P m is the grouting pressure range, kPa;

[0053] Subsequently, further determine the grouting pressure value P mn for grouting under the pipe section, which is the intermediate value within the allowable grouting pressure range and is calculated by Equation (10):

[0054] P mn =(P mmax+ P mmin ) / 2 (10);

[0055] Wherein, P mmax is the maximum allowable grouting pressure calculated in Equation (9), kPa;

[0056] P mmin is the minimum allowable grouting pressure calculated in Equation (9); kPa.

[0057] Specifically, in step S3, establish a calculation model for the settlement deformation of the soil layer under the pipe section and the compression deformation of the polymer grout after grouting and the expansion and curing of the grout, and calculate the final settlement amount of the soft soil foundation layer under the pipe section and the compression deformation amount of the grout body during the grouting and uplifting of the pipe section;

[0058] Among them, the final settlement amount s of the soft soil foundation layer under the pipe section during the grouting and uplifting of the pipe section is calculated through the following steps:

[0059] Calculate the contact stress P at the bottom surface of the misaligned pipe section through Equation (11):

[0060] (11);

[0061] Wherein, is the load acting on the top surface of the pipe section by the overlying soft soil during the uplifting of the pipe section, kPa;

[0062] P g is the self-weight load of the pipe section, kPa;

[0063] P m is the grouting pressure range, kPa;

[0064] Calculate the contact stress at the bottom of the misaligned pipe segment through Equation (12) :

[0065] (12);

[0066] In the formula, is the contact stress at the bottom of the pipe segment, kPa;

[0067] γ is the effective unit weight of the soil, kN / m³;

[0068] H is the buried depth of the pipe segment, m;

[0069] Calculate the total number of settlement soil layers n through Equation (13) as:

[0070] (13);

[0071] In the formula, n is the number of soil layers below the pipe segment;

[0072] is the depth of the soil layer under compression in the th layer, m;

[0073] D is the diameter of the pipeline or the width of the pipe gallery, m;

[0074] Calculate the additional stress at the depth z below the bottom surface of the pipe gallery through Equation (14) :

[0075] (14);

[0076] In the formula, the additional stress at the depth z below the bottom surface of the pipe gallery, kPa;

[0077] is the self-weight stress of the soil from the bottom surface of the pipe segment to the bedrock;

[0078] Calculate the additional stress of the i-th layer of soil under the center point of the bottom surface of the pipe segment through Equation (15) :

[0079] (15);

[0080] In the formula, is the stress coefficient of the i-th layer of compressed soil under the center point of the bottom surface of the pipe segment, and its calculation expression (16) is:

[0081] (16);

[0082] Wherein, m is the ratio of the length of the pipe segment to the diameter of the pipe segment or the width of the pipe gallery, i.e., ,

[0083] is the depth of the i-th layer of soil mass below the bottom surface of the pipe segment and the pipe diameter or the width of the pipe gallery ratio, i.e., ;

[0084] Thus, the settlement amount of the i-th underlying soil layer is calculated through Equation (17) :

[0085] 202411466612X (17);

[0086] Wherein, is the settlement amount of the i-th underlying soil layer below the center point of the bottom surface of the pipe segment, m;

[0087] is the stress coefficient of the i-th layer of compressed soil mass below the center point of the bottom surface of the pipe segment, kPa -1 ;

[0088] e is the void ratio of the i-th layer of soil mass before compression below the center point of the bottom surface of the pipe segment;

[0089] is the additional stress at, kPa;

[0090] is the thickness of the i-th layer of soil below the center point of the bottom surface of the pipe segment;

[0091] Finally, the final settlement amount of the soft soil foundation layer below the pipe segment during grouting lifting is calculated through Equation (18) :

[0092] (18);

[0093] where s i is the settlement amount of the i-th underlying soil layer below the center point of the bottom surface of the pipe segment, m;

[0094] s is the final settlement amount of the soft soil foundation layer below the pipe segment during grouting lifting, m;

[0095] The compression deformation amount of the polymer slurry is obtained through the following steps:

[0096] After the polymer polyurethane expands and cures, due to the self-weight of the pipe segment and the overburden pressure, the slurry is compressed to a certain extent. The total solidification compression amount l p is calculated by multiplying the final grouting height per unit length by the compression amount of the slurry per one-meter expansion and lifting :

[0097] Among them The calculation formula is:

[0098] = (19);

[0099] In the formula, l pi is the compression amount of the slurry per one-meter expansion and lift of the pipe jacking, m / m;

[0100] is the load acting on the top surface of the pipe segment by the overlying soft soil during the lifting process of the pipe segment, kPa;

[0101] P g is the self-weight load of the pipe segment, kPa;

[0102] E is the elastic modulus after the injected slurry is solidified, kPa;

[0103] The total solidification compression of the slurry The calculation formula is:

[0104] = (20);

[0105] is the final injected slurry height per meter, m;

[0106] is the compression amount of the slurry per one-meter expansion and lift of the pipe jacking, m / m.

[0107] Specifically, in step S4, the slurry height required per meter during the lifting of the stepped pipe segment is calculated through the following steps:

[0108] When the engineering requirement is to repair the lifting height of the stepped pipe segment to u, the final grouting height is the sum of the final settlement amount s of the soft soil foundation layer below the pipe segment during grouting and lifting, u, and the total solidification compression of the slurry, that is u + , the expansion rate of the polyurethane slurry is set as n, and the value of n ranges from 0 to 1. When n takes 0, it means the slurry does not expand, and when n takes 1, the volume of the slurry expands to twice the original; in actual engineering, different values of n are taken according to different working conditions. According to engineering experience, generally the value of n ranges from 0 to 1. Combining the above formulas, the slurry height required per meter of the pipe segment when the stepped pipe segment is repaired and lifted to a certain height u is calculated by formula (21):

[0109] ;

[0110] (21);

[0111] where \(l_0\) is the final height of the grout injected per meter, in m;

[0112] \(E\) is the elastic modulus after the injected grout solidifies, in kPa;

[0113] \(n\) is the expansion rate of the polyurethane grouting slurry;

[0114] \(u\) is the lifting height of the misaligned pipe section, in m;

[0115] \(s\) is the final settlement of the soft soil layer below the pipe section during the lifting of the pipe section by grouting, in m.

[0116] Since the expansion effect of the grout is not considered but the compression effect after its solidification is considered, the value of the final grouting height calculated by this method is a conservative value, which can offset the later settlement caused by the release of ground stress to a certain extent.

[0117] Specifically, in step S5, the specific steps of lifting and repairing are as follows:

[0118] S5-1: In the pipeline working condition, drill holes along the center line of the misaligned pipe section. The distance between each row of grouting holes is 0.05 times the length of the pipe section, the diameter of the grouting hole is 0.1 m, and one row is arranged;

[0119] In the pipe gallery repair working condition, drill holes at a distance of 0.25 times the width of the pipe gallery along the center line of the misaligned pipe section. The distance between each row of grouting holes is 0.05 times the length of the pipe section, the diameter of the grouting hole is 0.1 m, and two rows are arranged;

[0120] S5-2: Arrange the bladder bags in the odd-numbered rows of the drilled grouting holes. After the bladder bags and the diversion devices are set up, squeeze out the air in the bags, and then spiral-squeeze and fold the bladder bags and insert them into the grouting holes;

[0121] S5-3: Inject the high-polymer polyurethane grout inward for solidification and expansion for lifting and repairing. During grouting, the grouting pressure is the grouting pressure value \(P\) calculated in step S2 mn; For the underground pipeline working conditions, a grouting machine is used for grouting. After the grouting of the first bag laying hole is completed, polyurethane grouting is carried out in sequence to the next grouting hole for laying the bag, and so on until the grouting is completed. At the same time, the grouting height is selected as the final grouting height l0 calculated according to the parameters in the actual working conditions by using the above formula; For the single-chamber pipe gallery working conditions, two grouting machines are used for grouting simultaneously. Grouting starts from the drill holes in the first row and the first column, and the drill holes in the first row and the third column. After the grouting is completed, immediately grouting is carried out on the grouting holes at the positions of the drill holes (1,2) in the first row and the drill holes (1,4) in the first row. After the grouting in the first column is completed, the grouting machine is continuously transferred to the grouting holes at the positions of the drill holes (3,1) in the third row and the drill holes (3,3) in the third row for grouting. After the polyurethane grouting in the second column is completed, grouting is carried out on the grouting holes at the positions of the drill holes (3,2) in the third row and the drill holes (3,4) in the third row, and so on until the polyurethane slurry grouting process is completed. Among them, the selection of the slurry injection height is the final grouting height l0 calculated according to the parameters in the actual working conditions;

[0122] S5-4: Inject lightweight concrete into the remaining grouting holes; At the same time, when the polyurethane slurry in the bag expands and solidifies, the pipe section is lifted to the required height. At this time, there are gaps between the bags, and the gaps are filled with lightweight concrete.

[0123] Furthermore, the bag grouting device includes a grouting bag, a diversion pipe, a bag outlet pipe and a high-pressure pipe orifice of the grouting machine; A diversion pipe is arranged inside the grouting bag. The part of the diversion pipe located in the grouting bag is evenly provided with slurry diversion holes along the length direction. The end of the diversion pipe extending out of the grouting bag is connected to the bag outlet pipe and sealed with a water tape; The bag outlet pipe is connected to the high-pressure pipe orifice of the grouting machine through a reducing internal thread adapter.

[0124] Beneficial effects:

[0125] The present invention relates to a theoretical model and corresponding repair method for the grouting and lifting of offset underground pipelines and pipe corridors in soft soil. A mechanical model of the offset pipeline, pipe corridor and surrounding soil mass in the soft soil layer is established, and the range of grouting pressure during the grouting and lifting of offset pipe joints is determined. Based on the range of grouting pressure, a theoretical model of the settlement deformation of the soft soil layer under the pipe joint and the compression deformation after the slurry solidifies is established. Based on the above theoretical analysis, a method of laying a bladder and injecting a slurry material, namely high-polymer polyurethane, is proposed for the lifting and repair of offset pipe joints. It meets the safe bearing conditions of the underlying soil mass during the lifting and repair of offset pipe joints, improves the grouting efficiency, and realizes the control of the injection height of the slurry according to the characteristics of the soft soil layer, providing theoretical guidance for the grouting repair of the offset diseases of pipe corridors and pipelines in soft soil areas. By using the spatial constraint of the bladder and the expansibility and durability of the high-polymer polyurethane grouting material, good lifting effects of the offset pipe joints are achieved, meeting the safe operation of the later pipelines and pipe corridors and the normal use of underground pipelines, greatly reducing the dosage of the slurry material, saving costs and shortening the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0126] The following further specific description of the present invention is made in conjunction with the drawings, and the above and / or other advantages of the present invention will become clearer.

[0127] Figure 1 It is a schematic flow chart of a repair method for establishing a theoretical model provided by the present application and applying it to the grouting and lifting of offset underground pipelines and pipe corridors.

[0128] Figure 2 It is a schematic diagram of the mechanical model of the underground pipeline and single-chamber pipe corridor and the surrounding soil mass during the lifting process.

[0129] Figure 3 It is a schematic diagram of the theoretical model of the settlement deformation of the soft soil layer under the pipe joint and the compression deformation of the solidified slurry after grouting.

[0130] Figure 4 It is a schematic diagram of the layout of the bladder and the grouting sequence for the underground pipeline and single-chamber pipe corridor.

[0131] Figure 5 It is a schematic diagram of the grouting bladder device.

[0132] Wherein Figure 5 5-1 is the grouting bladder, 5-2 is the diversion pipe, 5-3 are the slurry diversion holes arranged on the diversion pipe, 5-4 is the water-stop tape, 5-5 is the reducing socket with male thread, 5-6 is the bladder outlet pipe, and 5-7 is the high-pressure nozzle of the grouting machine.

[0133] Figure 6 It is a comparison diagram of the repair of the offset disease of the underground pipeline.

[0134] Figure 7 It is a comparison diagram of the repair of the offset disease of the pipe corridor pipeline.

[0135] Figure 8 It is a schematic diagram of the steps for grouting to lift a sunken underground pipeline. Specific implementation manners

[0136] The present invention can be better understood according to the following embodiments.

[0137] When repairing a sunken pipe joint by grouting and lifting, determine the grouting pressure range to ensure the bearing safety of the underlying foundation while performing the lifting repair. The "trial-and-error method" and "empirical method" in previous projects refer to continuously trying different grouting pressures and relying on the experience of engineers to determine the grouting pressure. These two methods for determining grouting pressure are not universal and cannot accurately determine the grouting pressure range for different geological conditions, resulting in a longer construction time, more manpower and material resources, and low efficiency in the grouting construction process. Using the pipe-soil mechanical theory model to determine the grouting pressure range can directly grout and lift the sunken pipe joint, with higher construction efficiency.

[0138] Due to the characteristics of low strength and high compressibility of the soil in soft soil areas, the ground settlement deformation caused by grouting pressure should be taken into account during the pipeline lifting and repair, otherwise the lifting effect will not be ideal; the grouting material, high-polymer polyurethane, has expansibility and high elastic durability. However, during the expansion and lifting process, the incompletely cured grout will produce a certain amount of compression, although the compression amount is not large, it will also affect the lifting and repair effect to a certain extent. Therefore, when the pipeline needs to be lifted and repaired to a certain height, the compression amount of the underlying foundation settlement and the grout compression amount should be considered, and subsequent supplementary grout is used to achieve an ideal repair effect.

[0139] The existing grouting methods are splitting grouting, compaction grouting, and penetration grouting. Since there is no restraint after the grout is injected, a large amount of grout seeps and overflows, and it cannot accurately act under the sunken pipe joint to play a lifting role, resulting in a large amount of grouting material used and the need for multiple groutings, leading to a long construction time and low construction efficiency in the entire repair process, and a poor repair effect. Therefore, a lifting repair is carried out by arranging a bladder bag under the pipe joint and injecting expandable polyurethane grout, and the injected grout is accurately used for lifting repair, which can save costs, improve construction efficiency, and enhance the repair effect.

[0140] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0141] In an exemplary embodiment, as Figure 1 shown, a method for establishing and applying a theoretical model to the repair of sunken grouting and lifting of soft soil underground pipelines and pipe corridors includes the following steps S1 to S5. Among them:

[0142] S1: Establish the mechanical model of the pipe section and the surrounding soil during the lifting process;

[0143] S2: Based on the mechanical model described in step S1, determine the required grouting pressure range when grouting under the pipe section to repair the stepped pipeline corridor;

[0144] S3: Based on the grouting pressure range in step S2, establish a calculation model for the settlement deformation of the soil layer under the pipe section and the compression deformation of the high-polymer polyurethane grout after grouting and slurry expansion and solidification;

[0145] S4: Based on the calculation model in step S3, obtain the required slurry height per meter when lifting the stepped pipe section;

[0146] S5: Adopt the method of arranging the bladder under the pipe section, injecting high-polymer polyurethane into the bladder for lifting and repair, and filling lightweight concrete outside the bladder for reinforcement to lift and repair the stepped pipeline corridor.

[0147] Specifically, in step S1, the mechanical model of the pipe section and the surrounding soil during the lifting process is established through the following steps:

[0148] S1-1: Determine the load exerted by the overlying soft soil on the top surface of the pipe section during the lifting process of the pipe section :

[0149] S1-2: Determine the self-weight load P exerted by the pipe section on the underlying soil layer g ;

[0150] S1-3: Determine the ultimate bearing capacity Q of the foundation of the soil layer under the pipe section u .

[0151] Based on the load calculation formula, establish the mechanical model of the pipeline corridor and the soft soil during the lifting process, as Figure 2 shown.

[0152] Furthermore, in step S1-1, since the pipe section moves upward relative to the surrounding soft soil during the lifting process, in addition to the self-weight stress of the overlying soil layer, under the action of the soil arch, part of the load on the pipe section and on both sides of the pipe section is attracted to the top surface of the pipe section. Due to the difference in the shapes of the pipeline and the pipeline corridor, the corresponding lifting soil resistance is also different.

[0153] For a pipeline with a circular cross-section in the shape of a cylinder, the load exerted by the overlying soft soil on the top surface of the pipe section during the lifting process of the pipe section is calculated by formula (1):

[0154] (1);

[0155] For a linear pipeline corridor with a rectangular cross-section, the load exerted by the overlying soft soil on the top surface of the pipe section during its lifting process is calculated by formula (2):

[0156] (2);

[0157] Wherein, γ is the effective unit weight of the soil, kg / m³;

[0158] H is the buried depth of the pipeline or pipe gallery, m;

[0159] D is the pipeline diameter or the width of the pipe gallery, m;

[0160] f is the friction coefficient, which is calculated by the following formula (3):

[0161] (3);

[0162] Wherein, φ is the angle of internal friction of the soil, °.

[0163] Furthermore, in step S1-2, the self-weight load P of the pipe segment acting on the underlying soil layer g is calculated by the following formula (4):

[0164] (4);

[0165] Wherein, ρ is the density of the pipe segment material, kg / m 3 ;

[0166] V is the volume of the pipe segment, m 3 ;

[0167] g is the acceleration of gravity, m / s 2 ;

[0168] S is the effective cross-sectional area of the pipe segment, m 2 .

[0169] Furthermore, in step S1-3, the ultimate bearing capacity Q of the underlying soil layer of the pipe segment u is calculated by the following formula (5):

[0170] (5);

[0171] In the formula, N q、 N c、 N γ is the ultimate bearing capacity coefficient,

[0172] Wherein, N q is calculated by formula (6):

[0173] (6);

[0174] N c is calculated by formula (7):

[0175] (7);

[0176] N γ Calculated by formula (8):

[0177] (8);

[0178] φ is the internal friction angle of the soil, °;

[0179] c is the cohesion of the soil, kPa;

[0180] γ is the effective unit weight of the soil, kN / m³;

[0181] D is the pipeline diameter or the width of the pipe gallery, m;

[0182] H is the buried depth of the pipe joint, m.

[0183] Specifically, in step S2, based on the mechanical model, to lift the pipe joint, it is necessary to ensure that the grouting pressure is greater than the sum of the overburden pressure (lifting soil resistance) and the self-weight pressure of the pipe joint, while for the foundation stability, the sum of the overburden pressure (lifting soil resistance), the self-weight of the pipe joint plus the grouting pressure should not be greater than the ultimate bearing capacity of the foundation below it. Under the two limiting conditions of lifting and safety, by solving the simultaneous equations, the allowable range of grouting plus expansion pressure can be obtained, and further the grouting pressure for grouting under the pipe joint can be determined. The required grouting pressure range P for repairing the stepped pipeline and pipe gallery by grouting under the pipe joint m Determined by the following formula (9):

[0184] Q u -P s -P g ≤P m ≤Q u (9);

[0185] In the formula, Q u is the ultimate bearing capacity of the foundation of the soil layer under the pipe joint;

[0186] P g is the self-weight load of the pipe joint, kPa;

[0187] is the load acting on the top surface of the pipe joint by the overlying soft soil during the lifting process of the pipe joint, kPa;

[0188] P m is the grouting pressure range, kPa;

[0189] Subsequently, further determine the grouting pressure value P for grouting under the pipe joint mn , which is the middle value within the allowable grouting pressure range and is calculated by formula (10):

[0190] Pmn =(P mmax+ P mmin ) / 2 (10);

[0191] Wherein, P mmax is the maximum allowable grouting pressure calculated in Equation (9), kPa;

[0192] P mmin is the minimum allowable grouting pressure calculated in Equation (9); kPa.

[0193] Specifically, in step S3, due to the actions of grouting pressure, self-weight of the pipe segment, and overlying soil resistance to uplift, the underlying soil layer beneath the pipe segment will undergo compression settlement as the additional stress increases, and the grout may also undergo certain compressive deformation under vertical loads after solidification; therefore, a theoretical model for soil layer settlement and grout compressive deformation is established, and this model includes the final settlement of the underlying soft soil layer and the compressive deformation of the grout, as Figure 3 shown. A calculation model for settlement deformation of the soil layer beneath the pipe segment and compressive deformation of the polymer grout after grouting and grout expansion and solidification is established through the following steps to calculate the final settlement of the soft soil foundation layer beneath the pipe segment and the compressive deformation of the grout within the allowable grouting pressure range;

[0194] Among them, the final settlement s of the soft soil foundation layer beneath the pipe segment is calculated through the following steps:

[0195] The contact stress P at the bottom surface of the stepped pipe segment is calculated through Equation (11):

[0196] (11);

[0197] Wherein, is the load exerted by the overlying soft soil on the top surface of the pipe segment during the pipe segment uplift process, kPa;

[0198] P g is the self-weight load of the pipe segment, kPa;

[0199] P m is the allowable grouting pressure range, kPa;

[0200] The contact stress at the bottom surface of the stepped pipe segment is calculated through Equation (12) :

[0201] (12);

[0202] Wherein, is the contact stress at the bottom surface of the stepped pipe segment;

[0203] is the contact stress at the bottom surface of the pipe segment, kPa;

[0204] γ is the effective unit weight of the soil mass, kN / m³;

[0205] H is the buried depth of the pipe section, m;

[0206] The total number of settlement soil layers n is calculated by Equation (13) as follows:

[0207] (13);

[0208] In the formula, n is the number of soil layers divided under the pipe section;

[0209] is the depth of the i-th layer of soil mass under compression, m;

[0210] D is the diameter of the pipeline or the width of the pipe gallery, m;

[0211] The additional stress at a depth z below the bottom surface of the pipe gallery is calculated by Equation (14) :

[0212] (14);

[0213] In the formula, the additional stress at a depth z below the bottom surface of the pipe gallery, kPa;

[0214] is the self-weight stress of the soil mass from the bottom surface of the pipe section to the bedrock;

[0215] The additional stress of the i-th layer of soil under the center point of the pipe section bottom surface is calculated by Equation (15) :

[0216] (15);

[0217] In the formula, is the stress coefficient of the i-th layer of compressed soil mass under the center point of the pipe section bottom surface, and its calculation expression (16) is:

[0218] (16);

[0219] In the formula, m is the ratio of the length of the pipe section to the diameter of the pipe section or the width of the pipe gallery, that is ,

[0220] is the depth of the i-th layer of soil mass under the center point of the pipe section bottom surface and the diameter of the pipeline or the width of the pipe gallery ratio, that is ;

[0221] Thus, the settlement of the i-th underlying soil layer is calculated by Equation (17) :

[0222] (17);

[0223] Wherein, is the settlement of the i-th underlying soil layer below the center point of the bottom surface of the pipe segment, in m;

[0224] is the stress coefficient of the i-th compressed soil mass below the center point of the bottom surface of the pipe segment, in kPa -1 ;

[0225] e is the void ratio of the i-th soil layer before compression below the center point of the bottom surface of the pipe segment;

[0226] is the additional stress at, in kPa;

[0227] is the thickness of the i-th soil layer below the center point of the bottom surface of the pipe segment, in m;

[0228] Finally, the ultimate settlement of the soft soil foundation layer below the pipe segment is calculated by Equation (18) :

[0229] (18);

[0230] where s i is the settlement of the i-th underlying soil layer below the center point of the bottom surface of the pipe segment, in m;

[0231] s is the ultimate settlement of the soft soil foundation layer below the pipe segment, in m;

[0232] The compression deformation of the polymer slurry is obtained through the following steps:

[0233] After the polymer polyurethane expands and cures, the slurry is compressed to a certain extent due to the self-weight of the pipe segment and the overburden pressure. Considering the influence of compression on its expansion and lifting effect, a theoretical model of slurry compression deformation is established.

[0234] The theoretical model of slurry compression deformation is based on the following assumptions:

[0235] (1) The slurry does not produce lateral extrusion deformation. Due to the bag placement grouting method proposed in S5, the lateral extrusion deformation of the slurry is small based on this;

[0236] (2) The injected polymer slurry polyurethane is completely cured.

[0237] Based on the above mechanical model and theoretical model, the total compression amount l p is calculated by multiplying the final grouting height per meter by the compression amount of the slurry per one-meter expansion and lift :

[0238] in The calculation formula is:

[0239] = ; (19);

[0240] Where l pi is the amount of compression of the slurry for every meter of expansion and lifting, m / m;

[0241] is the load of the overlying soft soil acting on the top surface of the pipe segment during the pipe segment lifting process, kPa;

[0242] P g is the deadweight load of the pipe segment, kPa;

[0243] E is the elastic modulus of the injected slurry after curing, kPa;

[0244] Total compression The calculation formula is:

[0245] = (20);

[0246] In the formula The grouting height is per meter and the final slurry injection height is Slurry compression at 1 s, m;

[0247] The final slurry injection height per linear meter, m;

[0248] It is the amount of compression of the slurry for every meter of expansion, m / m.

[0249] Specifically, in step S4, the required slurry height per linear meter when the staggered pipe section is lifted is calculated by the following steps:

[0250] When the engineering requirement is to repair the misaligned pipe section, the final grouting height is u. It is the sum of the final settlement s, u of the soft soil layer below and the slurry solidification compression when the pipe segment is grouting and lifting, that is, u+ , the expansion rate of polyurethane slurry is set to n, the value of n is between 0 and 1, when n is 0, it means that the slurry does not expand, when it is 1, the slurry volume expands to twice its original value; in actual engineering, different values ​​of n are taken according to different working conditions. According to engineering experience, the value of n is generally between 0 and 1. Combining the above formulas, formula (21) is obtained to calculate the slurry height required for each linear meter of pipe section when the dislocated pipe section is repaired and lifted to a certain height u:

[0251] ;

[0252] (21);

[0253] In the formula, l0 is the final height of the grout injected per meter, in m;

[0254] E is the elastic modulus after the injected grout solidifies, in kPa;

[0255] n is the expansion rate of the polyurethane in the grouting slurry;

[0256] u is the lifting height of the misaligned pipe section, in m;

[0257] s is the final settlement of the soft soil foundation layer below the pipe section during the grouting and lifting, in m.

[0258] Since the expansion effect of the grout is not considered but the compression effect after its solidification is considered, the value of the final grouting height calculated by this method is a conservative value, which can offset the late settlement caused by the release of the ground stress to a certain extent.

[0259] Among the existing methods for grouting and lifting underground pipelines and the misalignment diseases of pipe galleries, it is further optimized and a method of arranging bladder bags under the pipelines or pipe galleries, injecting high-polymer polyurethane inward for lifting and repair, and filling lightweight concrete outward for reinforcement is proposed to lift and repair the misaligned pipe galleries and misaligned pipelines. For the grouting repair of misalignment, this application will elaborate on the method based on underground large-diameter pipelines and single-chamber pipe galleries as the repair objects. The steps and schematic diagrams of drilling and grouting for lifting and repair are as Figure 8 shown.

[0260] Specifically, in step S5, the lifting and repair are combined with Figure 4 , and the specific steps are as follows:

[0261] S5-1: In the pipeline condition, drill holes along the center line of the misaligned pipe section. The distance between each row of grouting holes is 0.05 times the length of the pipe section, the diameter of the grouting hole is 0.1 m, and one row is arranged.

[0262] In the pipe gallery repair condition, drill holes at a distance of 0.25 times the width of the pipe gallery along the center line of the misaligned pipe section. The distance between each row of grouting holes is 0.05 times the length of the pipe section, the diameter of the grouting hole is 0.1 m, and two rows are arranged; after the bladder bags and the diversion devices are set up, squeeze out the air in the bags, fold the bladder bags by spiral extrusion and insert them into the grouting holes, and then inject polyurethane slurry to solidify and expand for lifting.

[0263] S5-2: Arrange the bladder bags for the odd-numbered rows of grouting holes in the drilled holes. After the bladder bags and the diversion devices are set up, squeeze out the air in the bags, fold the bladder bags by spiral extrusion and insert them into the grouting holes.

[0264] S5-3: Inject the polymer polyurethane slurry inward for curing and swelling to perform lifting and repair. During grouting, the grouting pressure is the grouting pressure value P calculated in step S2. mn ; For the underground pipeline condition, use one grouting machine for grouting. After the first bladder bag layout hole is grouted, proceed to the next grouting hole for polyurethane grouting in sequence until the grouting is completed. At the same time, the grouting height is the final grouting height l0 calculated according to the parameters in the actual condition using the above formula; For the single-chamber pipe gallery condition, use two grouting machines for grouting simultaneously. Start grouting from the drilling holes in the first row and the first column, and the drilling holes in the first row and the third column. After the grouting is completed, immediately grout the grouting holes at the positions of the drilling holes (1,2) and (1,4) in the first row and the second column and the fourth column. After the first column is grouted, continue to transfer the grouting machine to the drilling holes (3,1) and (3,3) in the third row and the first column and the third column for grouting. After the second column of polyurethane grouting is completed, grout the grouting holes at the positions of the drilling holes (3,2) and (3,4) in the third row and the second column and the fourth column. Proceed in this way until the polyurethane slurry grouting process is completed. The selection of the slurry injection height is the final grouting height l0 calculated according to the parameters in the actual condition.

[0265] S5-4: Inject lightweight concrete into the remaining grouting holes; at the same time, when the polyurethane slurry in the bladder bags expands and cures, the pipe joints are lifted to the required height. At this time, there are gaps between the bladder bags, and use lightweight concrete to fill the gaps.

[0266] Furthermore, the bladder bag grouting device is as Figure 5 shown. The bladder bag grouting device includes a grouting bladder bag 5-1, a diversion pipe 5-2, a bladder bag outlet pipe 5-6, and a high-pressure nozzle of the grouting machine 5-7; A diversion pipe 5-2 is built inside the grouting bladder bag 5-1. The part of the diversion pipe 5-2 located in the grouting bladder bag 5-1 is evenly provided with slurry diversion holes 5-3 along the length direction. The end of the diversion pipe 5-2 extending out of the grouting bladder bag 5-1 is connected to the bladder bag outlet pipe 5-6 and sealed with a water tape 5-4; The bladder bag outlet pipe 5-6 is connected to the high-pressure nozzle of the grouting machine 5-7 through a reducing internal thread reducer 5-5.

[0267] When the polyurethane slurry in the bladder bags expands and cures, the pipe joints are lifted to a certain height. At this time, there are certain gaps between the bladder bags. At this time, use lightweight concrete to fill the gaps. After the lightweight concrete cures, it can reinforce the polyurethane slurry used for lifting and repairing the pipe gallery, strengthening the lifting effect.

[0268] It should be noted that during the polyurethane grouting process, it is necessary to ensure the tightness of the grouting bladder, especially at the bladder mouth. Otherwise, some slurry may leak, and after leakage, the slurry in the bladder will concentrate on the leakage side, resulting in a greater lifting force on this side than on the other side. Eventually, the pipe section will tilt after being lifted, affecting the lifting and repair effect of the pipe gallery.

[0269] Figure 6 The comparative schematic diagram of the repair of the offset disease of the underground pipeline is given. Among them, Figure 6 (a) Before repair, due to local differential settlement of soft soil at both ends of a certain pipe section, the two ends are displaced downward, resulting in an offset disease. After using the above grouting method for lifting and repair, from Figure 6 (c) The B-B cross-section diagram of the offset pipe section, it can be seen that after injecting and curing the high polymer and lightweight concrete slurry, the offset pipe section can be lifted and repaired. From Figure 6 (b) The A-A cross-section diagram and (c) the B-B cross-section diagram, it can be seen that the slurry does not flow and diffuse in large quantities like in traditional grouting projects due to the placement of the bladder, but is basically used for the lifting and repair of the pipeline, saving the grouting cost. At the same time, the injection of lightweight concrete strengthens the polyurethane slurry. This method not only ensures the compressive capacity of the slurry for lifting the pipe section, but also maximally solves the problems of long curing time and large slurry loss (excessive grouting pressure will cause splitting of the surrounding soil) caused by using only concrete slurry for grouting and lifting in the offset disease area of soft soil, and also avoids the problem of high material cost caused by using only polyurethane slurry.

[0270] Figure 7 It is the comparative schematic diagram of the repair of the offset disease of the pipe gallery pipeline. It can be seen that taking the repair of the offset of a single-cell pipe gallery as an example, when the slurry is injected, expanded and cured, it can play the role of lifting and repairing the offset pipe gallery. Figure 7 (b) is Figure 7 the A-A cross-section diagram marked in Figure 7 (a), Figure Seven (c) is

[0271] the B-B cross-section diagram marked in (a). It can be seen from the figure that two rows of grouting holes are arranged at the bottom of the single-cell pipe gallery, and the lightweight concrete fills the voids around the polyurethane slurry after curing and expansion, strengthening the lifting slurry. The arrangement of the bladders enables the polyurethane to act on the lifting and repair of the offset pipe section to the greatest extent; the voids between the bladders are filled with lightweight concrete, avoiding the flexural cracking of the concrete material of the pipe gallery, curing the polyurethane slurry and playing the role of strengthening the stability of the lifting system. Make full use of the advantages of both polyurethane and concrete materials and avoid their disadvantages. Use the characteristics of fast curing and high strength after curing of polyurethane to lift the offset pipe section, avoiding the disadvantage of slow curing of the concrete material used in traditional grouting repair; use the advantage of low material cost of the concrete material to fill the voids between the bladders with lightweight concrete, greatly reducing the material cost compared with using only polyurethane slurry.The present invention provides an idea and method for repairing the dislocation and lifting of underground pipelines and pipe corridors in soft soil. There are many methods and ways to specifically implement this technical solution. The above description is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by using the existing technology.

Claims

1. A method for repairing the misalignment of underground pipelines and pipe corridors in soft soil, characterized in that: The steps include: S1: Establish the mechanical model of the pipe segment and surrounding soil during lifting; S2: Determine the required grouting pressure range when grouting is performed below the pipe segment to repair the misaligned pipeline corridor based on the mechanical model described in step S1; S3: Based on the grouting pressure range of step S2, a calculation model for the settlement deformation of the soil layer below the pipe section and the compression deformation of the polymer polyurethane after grouting and slurry expansion and solidification is established; S4: Based on the calculation model of step S3, the required slurry height per linear meter when the wrong pipe section is lifted is obtained; S5: The dislocated pipe gallery is repaired by placing bags under the pipe sections, injecting high polymer polyurethane into the bags for lifting and repairing, and filling the bags with lightweight concrete for reinforcement.

2. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 1 is characterized in that: In step S1, a mechanical model of the pipe segment and the surrounding soil during the lifting process is established through the following steps: S1-1: Determine the load of the overlying soft soil on the top surface of the pipe segment during the lifting process : S1-2: Determine the deadweight load P of the pipe segment acting on the underlying soil layer g ; S1-3: Determine the ultimate bearing capacity Q of the soil layer beneath the pipe segment u .

3. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 2 is characterized in that: In step S1-1, for a cylindrical pipe with a circular cross section, the load of the overlying soft soil acting on the top surface of the pipe segment during the pipe segment lifting process is Calculated by formula (1): (1)； For a linear pipeline corridor with a rectangular cross section, the load of the overlying soft soil acting on the top surface of the pipeline segment during the lifting process is Calculated by formula (2): (2)； Where, γ is the effective density of soil, kN / m³; H is the buried depth of the pipeline or pipe gallery, m; D is the pipeline diameter or the width of the pipe gallery, m; f is the friction coefficient, which is calculated by the following formula (3): (3)； Where φ is the internal friction angle of soil, °.

4. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 2 is characterized in that: In step S1-2, the deadweight load P of the pipe segment acting on the underlying soil layer g It is calculated by the following formula (4): (4)； Where ρ is the density of the pipe material, kg / m 3 ; V is the volume of the tube segment, m 3 ; g is the acceleration due to gravity, m / s 2 ; S is the effective cross-sectional area of ​​the pipe segment, m 2 .

5. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 2 is characterized in that: In step S1-3, the ultimate bearing capacity of the soil layer under the pipe segment is Q u It is calculated by the following formula (5): (5)； Where N q、 N c、 N γ is the ultimate bearing capacity coefficient, Among them, N q Calculated by formula (6): (6)； N c Calculated by formula (7): (7)； N γ Calculated by formula (8): (8)； φ is the internal friction angle of soil, °; c is soil cohesion, kPa; γ is the effective density of soil, kN / m³; D is the pipeline diameter or the width of the pipe gallery, m; H is the buried depth of the pipe joint, m.

6. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 2 is characterized in that: In step S2, the required grouting pressure range P for grouting under the pipe joint to repair the misaligned pipeline gallery is m Determined by the following formula (9): (9)； In the formula, Q u is the ultimate bearing capacity of the foundation of the soil layer beneath the pipe segment; P g is the deadweight load of the pipe segment, kPa; is the load of the overlying soft soil acting on the top surface of the pipe segment during the pipe segment lifting process, kPa; P m is the grouting pressure range, kPa; Then, the grouting pressure value P used for grouting below the pipe section is further determined. mn , which is the middle value within the allowable grouting pressure range, is calculated by formula (10): P mn =(P mmax+ P mmin ) / 2 (10); Where P mmax is the maximum allowable grouting pressure calculated in formula (9), kPa; P mmin is the minimum allowable grouting pressure calculated in formula (9); kPa.

7. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 6 is characterized in that: In step S3, a calculation model for the settlement deformation of the soil layer below the pipe segment and the compression deformation of the polymer slurry after grouting and slurry expansion and solidification is established through the following steps to calculate the final settlement of the soft soil foundation layer below the pipe segment and the compression deformation of the slurry; Among them, the final settlement s of the soft soil layer under the pipe joint is calculated by the following steps: The contact stress P of the bottom surface of the misaligned pipe joint is calculated by formula (11): (11)； In the formula, is the load of the overlying soft soil acting on the top surface of the pipe segment during the pipe segment lifting process, kPa; P g is the deadweight load of the pipe segment, kPa; P m is the grouting pressure range, kPa; The contact stress on the bottom surface of the staggered pipe joint is calculated by formula (12): : (12)； In the formula, is the contact stress on the bottom surface of the pipe segment, kPa; γ is the effective density of soil, kN / m³; H is the buried depth of the pipe joint, m; The total number of settled soil layers n is calculated by formula (13): (13)； In the formula, For the Compression depth of layer soil, m; D is the pipeline diameter or the width of the pipe gallery, m; The additional stress at depth z below the bottom of the tunnel is calculated by formula (14): : (14)； In the formula, Additional stress at depth z below the bottom of the tunnel, kPa; is the soil self-weight stress from the bottom of the pipe section to the bedrock; The additional stress of the i-th layer of soil under the center point of the bottom surface of the pipe segment is calculated by formula (15): : (15)； In the formula, is the stress coefficient of the i-th layer of compressed soil under the center point of the bottom surface of the pipe segment, and its calculation expression (16) is: (16)； Where m is the ratio of the pipe segment length to the pipe segment diameter or the pipe gallery width, that is , is the depth of the i-th soil layer below the center point of the bottom surface of the pipe segment With pipe diameter or pipe gallery width The ratio of ; The settlement of the underlying soil layer under the i-th layer is calculated by formula (17): : (17)； In the formula, is the settlement of the i-th underlying soil layer below the center point of the bottom surface of the pipe segment, m; is the stress coefficient of the i-th layer of compressed soil under the center point of the bottom surface of the pipe segment, kPa -1 ; e is the void ratio of the i-th layer of soil under the center point of the bottom surface of the pipe segment before compression; for Additional stress at , kPa; is the thickness of the i-th soil layer below the center point of the bottom surface of the pipe segment, m; Finally, the final settlement of the soft soil layer below when the pipe segment is grouting and lifting is calculated by formula (18): : (18)； where s i is the settlement of the i-th underlying soil layer below the center point of the bottom surface of the pipe segment, m; The compression deformation of polymer slurry is calculated by the following steps: After the high polymer polyurethane expands and solidifies, the slurry is compressed to a certain extent due to the deadweight of the pipe segment and the pressure of the overlying soil. The total compression is l p Final grouting height per linear meter Multiply the amount of compression for each meter of expansion of the slurry calculate: in The calculation formula is: = (19)； Where l pi is the amount of compression of the slurry for every meter of expansion and lifting, m / m; is the load of the overlying soft soil acting on the top surface of the pipe segment during the pipe segment lifting process, kPa; P g is the deadweight load of the pipe segment, kPa; E is the elastic modulus of the injected slurry after curing, kPa; Total compression The calculation formula is: = (20)； In the formula The grouting height is per meter and the final slurry injection height is The compression of the slurry at the time, m; The final slurry injection height per linear meter, m; It is the amount of compression of the slurry for every meter of expansion, m / m.

8. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 7 is characterized in that: In step S4, the required slurry height per linear meter when the staggered pipe section is lifted is calculated by the following steps: When the engineering requirement is to repair the misaligned pipe section, the final grouting height is u. It is the sum of the final settlement s, u of the soft soil layer below and the slurry solidification compression when the pipe segment is grouting and lifting, that is, , the expansion rate of the polyurethane slurry is set to n, and the value of n is between 0 and 1. When the value of n is 0, it means that the slurry does not expand, and when it is 1, the slurry volume expands to twice its original value; Combining the above formulas, we get formula (21) to calculate the slurry height required for each linear meter of the pipe section when the dislocated pipe section is repaired and lifted to a certain height u: ； (21)； Where, l0 is the final slurry injection height per linear meter, m; E is the elastic modulus of the injected slurry after curing, kPa; n is the expansion rate of polyurethane in grouting slurry; u is the lifting height of the staggered pipe section, m; s is the final settlement of the soft soil layer below when the pipe segment is lifted by grouting, m.

9. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 8, characterized in that: In step S5, the specific steps of lifting and repairing are as follows: S5-1: In the pipeline working condition, holes are drilled along the center line of the staggered pipe section. The distance between each row of grouting holes is 0.05 times the length of the pipe section. The diameter of the grouting holes is 0.1m and they are arranged in one row. In the pipe gallery repair condition, holes are drilled along the center line of the dislocated pipe section at a distance of 0.25 times the width of the pipe gallery. The distance between each row of grouting holes is 0.05 times the length of the pipe section. The diameter of the grouting holes is 0.1m and they are arranged in two rows. S5-2: Arrange the bags for the odd-numbered rows of grouting holes. After the bags and diversion devices are set up, squeeze out the air in the bags, fold the bags by spiral extrusion and insert them into the grouting holes; S5-3: Inject high polymer polyurethane slurry into the interior to solidify and expand for lifting repair. The grouting pressure during grouting is the grouting pressure value P calculated in step S2. mn ; For underground pipeline working conditions, use one grouting machine for grouting. After the grouting of the first bag arrangement hole is completed, polyurethane grouting is carried out in sequence for the grouting hole of the next bag arrangement, and so on until the grouting is completed. At the same time, the grouting height is selected from the final grouting height l0 calculated according to the parameters in the actual working conditions by the above formula; For single-cabin pipe gallery working conditions, use two grouting machines for simultaneous grouting, starting from the drilled holes in the first row and the first column, and the drilled holes in the third row and the drilled holes in the third row and the drilled holes in the fourth row, and after the grouting is completed, the drilled holes in the second column of the first row and the drilled holes in the fourth column of the first row are grouted immediately. After the grouting of the first column is completed, the grouting machine is continued to be transferred to the first drilled hole in the third row and the drilled holes in the third row for grouting. After the polyurethane grouting of the second column is completed, the second drilled hole in the third row and the drilled holes in the fourth row are grouted, and so on until the polyurethane slurry grouting process is completed, wherein the slurry injection height is selected as the final grouting height l0 calculated according to the parameters in the actual working conditions; S5-4: Inject lightweight concrete into the remaining grouting holes; at the same time, when the polyurethane slurry in the bag expands and solidifies, the pipe section is lifted to the required height. At this time, there are gaps between the bags, which are filled with lightweight concrete.

10. The method for repairing the misaligned underground pipeline and pipe gallery in soft soil according to claim 9, characterized in that: The bag grouting device comprises a grouting bag (5-1), a guide pipe (5-2), a bag outlet pipe (5-6) and a grouting machine high-pressure pipe mouth (5-7); the grouting bag (5-1) has a built-in guide pipe (5-2); the guide pipe (5-2) is located in the grouting bag (5-1) and has slurry guide holes (5-3) uniformly opened along the length direction; the end of the guide pipe (5-2) extending out of the grouting bag (5-1) is connected to the bag outlet pipe (5-6) and sealed with a water tape (5-4); the bag outlet pipe (5-6) is connected to the grouting machine high-pressure pipe mouth (5-7) via a reducing joint (5-5) with a different diameter internal thread.

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