A grouting reinforcement method for a shield receiving section underpassing an existing line

Abstract

The present application relates to the technical field of shield construction, and discloses a grouting reinforcement method for a shield receiving section undercrossing an existing line, which comprises determining a shield receiving section, an existing line protection projection area and a receiving end influence area, and determining an overlapping range of the existing line protection projection area and the receiving end influence area; dividing the shield receiving section into a receiving end preposition reinforcement area, an existing line sandwich soil arch top reinforcement area, a shield shell peripheral filling area and a segment wall rear reinforcement area; before a shield machine shield head enters the receiving end influence area, the receiving end preposition reinforcement area and the existing line sandwich soil arch top reinforcement area are formed into a lap joint reinforcement; when a shield shell outer peripheral region enters the overlapping range, the shield shell peripheral filling area is formed; after segments in the segment wall rear reinforcement area are separated from a shield tail by a set number of rings, a continuous lap joint grouting reinforcement system is formed. The receiving end, the shield shell outer peripheral region and the segment wall rear reinforcement area are continuously lap jointed, and the risk of deformation of the existing line is reduced.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, specifically a grouting reinforcement method for the TBM receiving section passing under an existing railway line. Background Technology

[0002] In shield tunneling, when the shield machine approaches the receiving portal in the receiving section, it typically undergoes processes such as adjusting its excavation posture, breaking through the portal, removing the shield tail, and filling behind the tunnel lining segments. Compared to ordinary tunneling, the receiving section is more affected by factors such as the stability of the receiving portal end wall, the soil at the end, groundwater conditions, and the disturbance caused by the shield machine's advance. If the area also passes under an existing operating line, the interlayer soil between the newly constructed shield tunnel and the existing operating line tunnel structure will be disturbed by both the shield excavation and the receiving construction, which can easily cause problems such as settlement, differential deformation, or local soil loosening of the existing operating line tunnel structure.

[0003] In existing shield tunnel receiving section construction, end reinforcement is usually carried out in front of the receiving end, and the gaps behind the tunnel segment walls are filled by methods such as shield synchronous grouting and secondary grouting. For the case of passing under an existing operating line, the interlayer soil or the arch soil is also locally reinforced according to the protection requirements of the existing line. These measures can improve the stability of the soil at the receiving end and the filling effect behind the tunnel segment walls to a certain extent. However, in actual construction, the receiving end reinforcement, the interlayer soil reinforcement under the existing line, the outer perimeter filling during the shield shell passage, and the wall reinforcement after the tunnel segment exits the shield tail are often designed and constructed separately. The spatial correspondence between the reinforcement areas, the timing of construction triggering, and the connection between adjacent reinforcement bodies are not clear enough. Especially when the shield receiving section overlaps with the existing line protection projection area, the existing line protection risk and the receiving end construction risk are concentrated in the same area. If only the soil in front of the receiving portal is reinforced, it may be difficult to cover the interlayer soil between the existing operating line tunnel structure and the arch of the newly built shield tunnel. If only the wall grouting behind the shield tail is relied upon, it is difficult to deal with the loose space on the outer perimeter of the shield shell when the shield shell passes through the overlapping area in a timely manner.

[0004] To address the aforementioned issues, it is imperative to innovate the existing grouting reinforcement method for the shield tunnel receiving section when it passes under the existing railway line. Summary of the Invention

[0005] The purpose of this invention is to provide a grouting reinforcement method for shield tunnel receiving sections passing under existing railway lines, so as to solve the problems existing in the grouting reinforcement methods for shield tunnel receiving sections passing under existing railway lines as mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line, comprising: S1. Determine the shield receiving section, the existing line protection projection area, and the receiving end influence area, and determine the overlap range between the existing line protection projection area and the receiving end influence area; S2. The shield receiving section is divided into a receiving end pre-reinforcement area, an existing line interlayer soil arch reinforcement area, a shield shell perimeter filling area, and a segment wall back reinforcement area; wherein, the shield shell perimeter filling area corresponds to the outer periphery of the shield shell within the overlapping range, and the segment wall back reinforcement area corresponds to the existing line protection projection area, the receiving end influence area, and the area behind the outer wall of the segment within the overlapping range. S3. Before the shield head of the tunnel boring machine enters the influence zone of the receiving end, full-section horizontal deep hole grouting is carried out in the front reinforcement zone of the receiving end, and horizontal deep hole grouting is carried out in the arch top reinforcement zone of the existing line interlayer soil, so that the front reinforcement zone of the receiving end and the existing line interlayer soil arch top reinforcement zone form an overlapping reinforcement. S4. When the outer periphery of the shield shell enters the overlapping range, mud-resistant material is injected into the outer side of the shield shell through the radial grouting holes of the tunnel boring machine to form a periphery filling area of ​​the shield shell. S5. When the segment in the reinforcement zone behind the segment wall has exited the shield tail to a set number of rings, reinforcement grout is injected into the reinforcement zone behind the segment wall through at least one of the segment grouting holes and reserved grouting pipes, so that a reinforcement grouting body is formed in the area behind the outer wall of the segment, and a continuous overlapping grouting reinforcement system is formed between the receiving end front reinforcement zone, the existing line interlayer soil arch reinforcement zone, the shield shell perimeter filling zone and the reinforcement zone behind the segment wall.

[0007] Furthermore, in S1, the shield receiving section is the construction section located in front of the receiving portal in the newly built shield tunnel, and the shield receiving section covers the receiving end influence area, the existing line protection projection area, and the overlapping range. The existing line protection projection area is determined based on the outer contour of the existing operating line tunnel structure, the design axis of the new shield tunnel, the allowable deformation control value of the existing operating line, and the geological conditions. The receiving end influence zone is determined by extending along the direction of the shield tunnel, with the receiving tunnel portal end wall as the reference. The overlapping range refers to the area where the existing line protection projection area and the receiving end influence area overlap in the longitudinal and vertical directions of the shield tunnel.

[0008] Furthermore, in S3, full-section horizontal deep-hole grouting is performed on the pre-reinforcement area of ​​the receiving end, including: Using the end wall of the receiving tunnel as the reference for hole layout, horizontal deep holes and external inclined holes are drilled from the working face inside the main structure of the receiving well and the working face inside the cross passage to the receiving end pre-reinforcement area. The horizontal deep holes extend longitudinally along the shield tunnel line, and the external inclined holes extend inclinedly from the periphery of the receiving tunnel to the outer edge of the receiving end pre-reinforcement area. The longitudinal reinforcement length of the receiving end pre-reinforcement area is 8-12m, and the reinforcement range of the receiving end pre-reinforcement area covers the soil above, below and on the left and right sides of the shield tunnel outline. The horizontal deep holes and the externally inserted oblique holes are arranged in a quincunx pattern. The externally inserted oblique holes are arranged with at least two levels of external insertion angles, and the depth of the externally inserted oblique holes decreases as the external insertion angle increases. A repeatable grouting pipe is installed in the horizontal deep hole for re-grouting the pre-reinforcement zone of the receiving end.

[0009] Furthermore, in S3, horizontal deep-hole grouting is performed on the arch crown reinforcement zone of the existing line interlayer soil, including: Using the reserved grouting area of ​​the secondary lining end wall of the receiving station as the working surface for drilling, horizontal deep holes are drilled into the interlayer soil between the existing operating line tunnel structure and the arch of the newly built shield tunnel. The horizontal deep holes are located in the arch reinforcement area of ​​the existing line interlayer soil and extend longitudinally along the shield line. The horizontal deep hole at the top of the arch was constructed using segmented drilling and segmented grouting methods. Each grouting section is drilled and grouted through the borehole pipe, and the grouting termination conditions within the section are determined according to the design grouting pressure, design grouting volume, and borehole return grouting status. After each grouting section is completed in sequence, a crown reinforcement zone is formed in the existing line interlayer soil crown reinforcement zone, which is continuously distributed along the existing line protection projection area.

[0010] Furthermore, in S3, the overlapping reinforcement between the receiving end pre-reinforcement zone and the existing line interlayer soil arch reinforcement zone includes: Based on the relative position of the receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area, the grouting hole spacing and the effective diffusion radius of the grout, the hole layout positions of the horizontal deep holes, the external inclined holes and the arch horizontal deep holes are determined. The distance between adjacent grouting holes shall not exceed the sum of the effective diffusion radii of the two adjacent holes; The effective diffusion range of the horizontal deep hole, the external inclined hole and the arch horizontal deep hole extends to the overlap section between the receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area. The receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area are connected to each other in the longitudinal and vertical directions of the shield tunnel through the overlapping section, so that the reinforcement body around the receiving portal is continuously connected to the interlayer soil reinforcement zone under the existing operating line tunnel structure.

[0011] Furthermore, in S4, a mud-resistant material is injected into the outer side of the shield shell through the radial grouting holes of the tunnel boring machine, including: Equipment for preparing and injecting mud-resistant materials is installed on the tunnel boring machine trailer; When the outer periphery of the shield shell enters the overlapping range, the radial grouting holes of the tunnel boring machine are activated in groups according to the circumferential position of the shield shell. First, inject the mud-repellent material into the top and shoulder of the shield, and then inject the mud-repellent material into the sides of the shield. The amount of the mud-repellent material injected is 1.1-1.5 times the theoretical void volume of the outer periphery of the shield.

[0012] Further, in S5, reinforcing grout is injected into the reinforcement zone behind the segment wall through at least one of the segment grouting holes and reserved grouting pipes, including: After the segment in the reinforcement zone behind the segment wall is removed from the shield tail 3-7 rings, secondary deep hole grouting is carried out using at least one of the segment grouting holes and reserved grouting pipes. The reinforcing grout is a two-component grout; The secondary deep hole grouting adopts multiple grouting holes for grouping and injection, with each grouting hole being injected in at least two cycles; Grouting pressure should be controlled between 0.4 and 1.2 MPa; The design diffusion radius of the reinforcing grout is 0.20-0.30m, so that a reinforcing grout body with an effective thickness of not less than 1.5m is formed on the outside of the segment.

[0013] Furthermore, the reinforcement area behind the segment wall includes the boundary portion of the existing line protection projection area near the boundary of the existing line protection projection area, the central portion of the existing line protection projection area located in the middle of the existing line protection projection area, and the adjacent portion of the receiving tunnel door near the end wall of the receiving tunnel door. The grouting holes in the boundary of the existing line protection projection area, the center of the existing line protection projection area, and the area adjacent to the receiving tunnel portal are divided into arch top group, arch waist group, side wall group, and invert arch group according to the circumferential position of the tunnel segments. The grouting sequence is as follows: first, reinforce the boundary of the existing line protection projection area and the area near the receiving tunnel portal, and then reinforce the center of the existing line protection projection area. At least one of the segment grouting holes and reserved grouting pipes used to inject reinforcing grout into the rear reinforcement area of ​​the segment wall is offset from the shield longitudinal injection position corresponding to the radial grouting hole of the shield machine by at least one segment length. When grouting holes and reserved grouting pipes are installed simultaneously in the same segment ring, adjacent grouting holes and reserved grouting pipes shall be staggered by at least one hole position upwards in the segment ring.

[0014] Furthermore, water-stop valves are installed at the openings of the grouting holes and the reserved grouting pipes of the segments; The grouting holes for the segments are arranged to avoid the main reinforcement bars of the segments; After the reinforcement grouting is completed, the grouting head connected to the grouting hole of the segment and the reserved grouting pipe is removed, and double-fast cement mortar is filled into the grouting hole of the segment and the reserved grouting pipe; After the double-fast cement mortar is filled, screw plugs are installed at the outer ends of the grouting holes and reserved grouting pipes of the pipe segments, so that the grouting holes and reserved grouting pipes of the pipe segments form a double-fast cement mortar sealing section and a screw plug sealing section from the inside to the outside.

[0015] Furthermore, the full-section horizontal deep hole grouting and arch-top horizontal deep hole grouting in S3, the injection of mud-effective material in S4, and the injection of reinforcing grout in S5 are all controlled by the injection control unit to stop the injection. The injection control unit is a single injection operation for a single grouting hole; when the horizontal deep hole at the arch is constructed using segmented drilling and segmented grouting, a single grouting segment within a single grouting hole is considered as an injection control unit. Each injection control unit determines the injection stop status based on the current injection pressure, injection volume per unit time, and cumulative injection volume; The full-section horizontal deep hole grouting in S3, the horizontal deep hole grouting at the arch crown, and the reinforcing grout injection in S5 also determine the grouting stop status in combination with the grout return status at the borehole opening. When the settlement change value of the existing operating line reaches the preset suspension threshold, the injection control unit currently under construction will be suspended.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This grouting reinforcement method for the shield receiving section crossing the existing line divides the overlapping risk area of ​​the shield receiving section crossing the existing line into a pre-reinforcement zone, an existing line interlayer soil arch reinforcement zone, a shield shell perimeter filling zone, and a segment wall reinforcement zone. Pre-grouting, shield shell perimeter filling, and segment wall reinforcement grouting are then implemented sequentially, forming a continuous overlapping grouting reinforcement system for each reinforcement zone, as detailed below: 1. The overlapping range of the existing line protection projection area and the receiving end influence area is used as the basis for the reinforcement control of the shield receiving section. The shield shell perimeter filling area corresponds to the outer perimeter area of ​​the shield shell within the overlapping range, and the segment wall reinforcement area corresponds to the existing line protection projection area, the receiving end influence area and the outer side wall area of ​​the segment within the overlapping range. This allows the receiving end soil, the interlayer soil under the existing line, the outer perimeter space of the shield shell and the segment wall area to correspond to clear grouting reinforcement objects, which facilitates the subsequent grouting construction to be carried out by area. 2. Before the shield tunnel enters the receiving end's influence zone, full-section horizontal deep-hole grouting is carried out in the receiving end's pre-reinforcement zone, and horizontal deep-hole grouting is carried out in the existing line's interlayer soil arch reinforcement zone. This allows the receiving end's pre-reinforcement zone and the existing line's interlayer soil arch reinforcement zone to form an overlapping reinforcement, thereby connecting the reinforcement body around the receiving portal with the interlayer soil reinforcement zone under the existing operating line tunnel structure in the longitudinal and vertical directions of the shield tunnel, reducing the possibility of unreinforced connection sections between the two types of pre-reinforcement zones. 3. When the outer periphery of the shield shell enters the overlapping area, mud-resistant material is injected into the outer side of the shield shell through the radial grouting holes of the tunnel boring machine to form a periphery filling area of ​​the shield shell; after the segment has exited the shield tail and reached the set number of rings, reinforcing grout is injected into the reinforcement area behind the segment wall, so that the periphery filling during the shield shell passage and the reinforcement behind the wall after the segment exit are connected in terms of construction sequence and spatial position, thereby forming a continuous overlapping grouting reinforcement system between the receiving end pre-reinforcement area, the existing line interlayer soil arch reinforcement area, the shield shell periphery filling area and the segment wall reinforcement area. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the grouting reinforcement method for the shield tunnel receiving section passing under an existing railway line according to the present invention. Figure 2 A schematic diagram showing the determination of the shield receiving section, the existing line protection projection area, the receiving end influence area, and the overlapping range of the present invention. Figure 3 This is a schematic diagram showing the four zones of the present invention: the receiving end front reinforcement zone, the existing line interlayer soil arch reinforcement zone, the shield shell perimeter filling zone, and the segment wall back reinforcement zone. Figure 4 This is a schematic diagram of the deep hole grouting overlap of the horizontal deep hole, the external inclined hole, the horizontal deep hole at the top of the arch, and the overlapping section of the present invention. Figure 5 This is a schematic diagram of the injection of the mud-repellent material of the present invention; Figure 6 This is a schematic diagram of the rear wall reinforcement zone of the segment, the grouting hole of the segment, and the reserved grouting pipe of the present invention; Figure 7 A schematic diagram of the control logic for the injection control unit of this invention to perform injection stop control and pause control; Figure 8 This is a schematic diagram of the grouting reinforcement system of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: This invention provides a technical solution: a grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line, comprising: S1. Determine the shield receiving section, the existing line protection projection area, and the receiving end influence area, and determine the overlap range between the existing line protection projection area and the receiving end influence area.

[0020] In specific implementation, the design axis of the new shield tunnel, the position of the receiving portal end wall, the outer contour of the existing operating line tunnel structure, the vertical clearance of the line, the horizontal intersection relationship of the line, and the allowable deformation control value of the existing operating line are used as basic data to establish the spatial correspondence between the receiving portal, the existing operating line tunnel structure, and the new shield tunnel. Among them, the existing operating line tunnel structure refers to the main load-bearing structure of the already built and protected operating subway, railway, or municipal tunnel, including the protected outer contour of the segment structure, lining structure, and track bed structure. The output results are the initial spatial positions of the shield receiving section, the existing line protection projection area, and the receiving end influence area.

[0021] The shield receiving section is the construction area in front of the receiving portal in a newly constructed shield tunnel. The shield receiving section covers the receiving end influence area, the existing line protection projection area, and the overlapping area. In this implementation plan, the section of the newly constructed shield tunnel along the end wall of the receiving portal forward of the shield is defined as the shield receiving section. This shield receiving section covers the continuous construction area involved in the shield machine approaching the receiving portal, the shield machine passing under the existing line protection projection area, the shield tail exiting the existing line protection projection area, and the reinforcement construction behind the tunnel segments. The length of the shield receiving section is determined by the distance from the receiving portal to the structural projection range of the existing operating line tunnel, the length of the shield machine, the circumference of the tunnel segments, and the length of the receiving end reinforcement. This ensures that the subsequent receiving end pre-reinforcement, shield shell perimeter filling, and tunnel segment wall reinforcement all fall within the same construction section for unified control. The output results are the start and end mileage of the shield receiving section and the corresponding shield construction section.

[0022] The protection projection area for the existing line is determined based on the outer contour of the existing operating line tunnel structure, the design axis of the new shield tunnel, the allowable deformation control value of the existing operating line, and the geological conditions. Specifically, the outer contour of the existing operating line tunnel structure is projected vertically onto the soil layer where the new shield tunnel is located. Combined with the allowable settlement, allowable uplift, allowable differential deformation, overburden thickness, interlayer soil thickness, groundwater conditions, and geological stability of the existing operating line, the protection boundary is extended longitudinally and laterally towards the shield tunnel to form a protection boundary. The allowable deformation control value of the existing operating line can be determined by the operation and maintenance requirements of the existing operating line, the design protection standard, or a special protection plan. The geological conditions include the type of interlayer soil, water content, permeability, and self-stabilizing capacity. The output results are the longitudinal boundary, lateral boundary, and vertical protection range of the protection projection area for the existing line.

[0023] The affected area of ​​the receiving end is determined by extending along the direction of the shield tunnel, with the end wall of the receiving tunnel portal as the reference. In practice, the cross-section where the receiving tunnel portal end wall is located is used as the reference cross-section. The range of strata affected by the tunnel portal breach, shield reception, end soil stability, and shield tail disengagement is determined along the direction of the tunnel boring machine. The soil in front of the receiving end that requires full-section horizontal deep hole grouting is included in the receiving end influence zone. The extension length of the receiving end influence zone can be determined based on the stratum stability at the receiving tunnel portal, the shield diameter, the tunnel portal water sealing requirements, and the receiving end reinforcement design length. When the original construction data provides the longitudinal reinforcement length of the receiving end, this reinforcement length is given priority as the main control length of the receiving end influence zone. The output results are the extension distance and spatial boundary of the receiving end influence zone relative to the receiving tunnel portal end wall.

[0024] The overlapping range is the area where the existing line protection projection area and the receiving end influence area overlap in the longitudinal and vertical directions of the shield. In specific construction control, the overlapping range is also constrained by the lateral protection boundary of the existing line protection projection area. The lateral protection boundary is determined based on the outer contour of the existing operating line tunnel structure, the design axis of the new shield tunnel, and the geological conditions. When the existing line protection projection area and the receiving end influence area overlap in the longitudinal and vertical directions of the shield, the soil, the outer perimeter space of the shield shell, and the area behind the outer wall of the segment within the lateral protection boundary of the overlapping area are used as the control objects for subsequent grouting and material injection. The output result is the overlapping range with longitudinal, vertical, and lateral construction control boundaries. In practice, the existing line protection projection area and the receiving end influence area are spatially superimposed. The soil and tunnel periphery space within the common coverage area are defined as the overlapping range. This overlapping range corresponds to the area where shield receiving risk and existing operating line protection risk coexist. The subsequent shield shell periphery filling area takes the shield shell periphery area within this overlapping range as the main control object. The segment wall reinforcement area covers the area behind the outer wall of the segment affected by the overlapping range and the area before and after it. The output results are the start and end mileage of the overlapping range, the vertical interlayer position and the corresponding risk control object.

[0025] When determining the above-mentioned areas, the design axis of the newly built shield tunnel is used as the longitudinal positioning reference, the end wall of the receiving portal is used as the receiving end positioning reference, and the outer contour of the existing operating line tunnel structure is used as the existing line protection positioning reference. The receiving end influence area, the existing line protection projection area and the overlapping range are marked on the shield line longitudinal section, plan layout and cross section, respectively. This allows the receiving end pre-reinforcement area, the existing line interlayer soil arch reinforcement area, the shield shell perimeter filling area and the segment wall back reinforcement area in S2 to be divided according to a unified spatial reference. The output result is the shield receiving section spatial zoning foundation map for subsequent zoning grouting design.

[0026] S2. The shield receiving section is divided into the receiving end pre-reinforcement zone, the existing line interlayer soil arch reinforcement zone, the shield shell perimeter filling zone, and the segment wall back reinforcement zone; among which, the shield shell perimeter filling zone corresponds to the outer perimeter area of ​​the shield shell within the overlapping range, and the segment wall back reinforcement zone corresponds to the existing line protection projection area, the receiving end influence area, and the area behind the outer wall of the segment within the overlapping range.

[0027] In specific implementation, based on the shield receiving section, existing line protection projection area, receiving end influence area and overlapping range obtained from S1, the longitudinal mileage of the shield line, the outer contour of the shield tunnel, the outer contour of the existing operating line tunnel structure and the receiving portal end wall are used as common positioning benchmarks. The soil in front of the receiving portal that needs to be pre-reinforced in the shield receiving section is designated as the receiving end pre-reinforcement area. The interlayer soil between the existing operating line tunnel structure and the arch of the newly built shield tunnel is designated as the existing line interlayer soil arch reinforcement area. The space between the outer side of the shield shell and the surrounding soil that needs to be filled immediately when the shield shell passes through the overlapping range is designated as the shield shell perimeter filling area. The space behind the outer wall of the segment that has already detached from the shield tail in the existing line protection projection area, receiving end influence area and overlapping range is designated as the segment wall back reinforcement area. The output result is the spatial division result of the four grouting control areas in the shield receiving section.

[0028] The receiving end pre-reinforcement zone is used to support the subsequent full-section horizontal deep hole grouting in S3. In specific implementation, the receiving portal end wall is the boundary closest to the receiving end, the predetermined reinforcement length in the direction of the shield tunnel is the boundary furthest from the receiving end, and the soil area above, below, and on both sides of the outer contour of the shield tunnel that needs to be reinforced is the lateral and vertical boundary. This area covers the soil affected by the portal breach, shield receiving, and receiving end water stop stability. The division result of the receiving end pre-reinforcement zone is used to determine the hole layout range of the horizontal deep holes and external inclined holes. The output results are the longitudinal length, lateral width, and vertical coverage range of the receiving end pre-reinforcement zone. The existing line interlayer soil arch reinforcement zone is used to support the subsequent horizontal deep hole grouting of the arch in S3. In specific implementation, the upper control boundary is the protection boundary below the existing operating line tunnel structure, the lower control boundary is the soil outside the arch of the newly built shield tunnel, and the longitudinal control boundary is the protection range of the existing line protection projection area in the longitudinal direction of the shield. The interlayer soil between the two tunnels that is disturbed by the shield tunneling and needs to form a continuous arch reinforcement zone through horizontal deep hole grouting is included in this area. The interlayer soil refers to the soil between the existing operating line tunnel structure and the arch of the newly built shield tunnel that has not yet been excavated but will be disturbed by the shield receiving construction. The output results are the longitudinal extension range and the vertical interlayer range of the existing line interlayer soil arch reinforcement zone.

[0029] In this implementation plan, the shield perimeter filling area corresponds to the outer perimeter of the shield within the overlapping range. The circumferential outer space occupied by the outer contour of the shield as the tunnel boring machine (TBM) advances into the overlapping range is defined as the shield perimeter filling area. This area moves longitudinally along the TBM as the TBM position changes. Its control object is the instantaneous relaxation space formed between the shield top, shoulder, sides, and adjacent surrounding soil due to the passage of the TBM. The division of the shield perimeter filling area is used to limit the spatial timing and circumferential position of the TBM radial grouting holes in subsequent S4. The output result is the outer perimeter of the shield within the overlapping range that needs to be injected with mud-effect material. In this implementation plan, the shield perimeter filling area is mainly controlled by the outer perimeter of the shield corresponding to the shield top, shoulder, and sides. It is not required that the entire circumference of the shield be injected in the same way. For the bottom of the shield, it is only controlled as a supplementary injection location when the TBM attitude, the state of soil relaxation, the injection pressure, or the monitoring results show that there are abnormal gaps or disturbance risks at the bottom.

[0030] In this implementation plan, the reinforcement area behind the tunnel segment wall corresponds to the area behind the outer wall of the tunnel segment within the existing line protection projection area, the receiving end influence area, and the overlapping area. The outer space of the tunnel segment that has been assembled and detached from the shield tail within the existing line protection projection area, the receiving end influence area, and the overlapping area is defined as the reinforcement area behind the tunnel segment wall. This area is located between the outer wall of the tunnel segment and the surrounding soil, and covers the area where the shield tail may form a void behind the wall, locally loose soil, and weak parts for later settlement after detachment. The division result of the reinforcement area behind the tunnel segment wall is used to determine the target of the grouting holes, reserved grouting pipes, and reinforcement grout in the subsequent S5. The output result is the area behind the outer wall of the tunnel segment that needs to be grouted in a second deep hole. In this embodiment, the reinforcement area behind the tunnel segment wall is based on the existing line protection projection area, the receiver influence area, and the area behind the outer wall of the tunnel segment within the overlapping range. The area behind the outer wall of the tunnel segment, which is jointly affected by the existing line protection projection area and the receiver influence area, is the core reinforcement object. At the same time, the area behind the outer wall of adjacent tunnel segments that are near the boundary of the existing line protection projection area, near the receiver portal end wall, and affected by disturbances after the shield tail exits are included in the reinforcement control range. Among them, the area behind the outer wall of the tunnel segment within the overlapping range is used to receive the filling control during the shield shell passage period, the area near the boundary of the existing line protection projection area is used to form boundary reinforcement, and the area near the receiver portal end wall is used to control the sensitive parts of the receiver settlement in the later stage. The output result is the reinforcement area behind the tunnel segment wall with the overlapping range as the core and extending to the adjacent affected parts.

[0031] After the four grouting control zones are divided, the adjacent parts between the receiving end pre-reinforcement zone and the existing line interlayer soil arch reinforcement zone are marked as the pre-overlap joints. The adjacent parts between the shield shell perimeter filling zone and the receiving end pre-reinforcement zone and the existing line interlayer soil arch reinforcement zone are marked as the passing-through joints. The adjacent parts between the segment wall back reinforcement zone and the shield shell perimeter filling zone are marked as the post-exit reinforcement joints. This allows subsequent S3, S4, and S5 to be grouted and injected with materials sequentially according to the same spatial partition. The output result is a grouting control zone map of the shield receiving section, including the receiving end pre-reinforcement zone, the existing line interlayer soil arch reinforcement zone, the shield shell perimeter filling zone, the segment wall back reinforcement zone, and their adjacent joints.

[0032] S3. Before the shield head of the tunnel boring machine enters the receiving end's influence zone, full-section horizontal deep hole grouting is carried out in the receiving end's pre-reinforcement zone, and horizontal deep hole grouting is carried out in the existing line's interlayer soil arch reinforcement zone, so that the receiving end's pre-reinforcement zone and the existing line's interlayer soil arch reinforcement zone form an overlapping reinforcement.

[0033] Specifically, the construction period before the tunnel boring machine (TBM) shield head enters the receiving end's influence zone is designated as the pre-reinforcement period. During this pre-reinforcement period, horizontal deep-hole grouting is first performed on the entire cross-section of the soil in front of the receiving portal. Then, horizontal deep-hole grouting is performed on the interlayer soil between the existing operating tunnel structure and the arch of the newly built TBM tunnel. This allows the soil around the receiving portal to first form a reinforced body capable of withstanding the portal breach and the disturbance caused by the TBM receiving, and the interlayer soil area to form an arch reinforcement zone capable of meeting the deformation control requirements of the existing operating line. The output result is the soil in front of the receiving end... The construction sequence and objects of pre-grouting in the reinforced area and the reinforced area of ​​the existing line interlayer soil arch are described below. In this embodiment, full-section horizontal deep hole grouting is a full-section reinforcement method at the receiving end, with horizontal deep holes as the main body and external inclined holes as the boundary supplementary holes. Among them, the horizontal deep holes mainly cover the soil directly in front of the shield tunnel outline and its adjacent soil above, below, left and right, while the external inclined holes are used to supplement and cover the soil around the receiving portal, the arch shoulder, the corners, and the outer edge soil that is difficult to be directly covered by the horizontal deep holes. Together, they constitute the full-section grouting hole group in the pre-reinforcement area of ​​the receiving end. Therefore, the full-section horizontal deep hole grouting referred to thereafter includes horizontal deep hole grouting and external inclined hole grouting implemented in conjunction with the horizontal deep holes.

[0034] In this implementation plan, the receiving tunnel portal end wall is used as the borehole layout reference. Horizontal deep holes and external inclined holes are drilled from the working faces inside the main structure of the receiving shaft and the working faces inside the cross passage to the receiving end pre-reinforcement area. The horizontal deep holes extend longitudinally along the shield tunnel line, and the external inclined holes extend obliquely from the periphery of the receiving tunnel portal to the outer edge of the receiving end pre-reinforcement area. Specifically, the plane where the receiving tunnel portal end wall is located is used as the borehole layout reference. The wall surface inside the main structure of the receiving shaft that can be drilled, the working face around the tunnel portal, and the working face inside the cross passage are used as the drilling rig positioning positions. The horizontal deep holes point longitudinally along the shield tunnel line towards the interior of the receiving end pre-reinforcement area to cover the soil directly in front of the shield tunnel outline. The external inclined holes extend obliquely from the periphery of the receiving tunnel portal to the outer edge of the receiving end pre-reinforcement area to enter the soil to cover the tunnel portal boundary, arch shoulder, and corner areas that are difficult to cover by the horizontal deep holes. The output result is the drilling direction of the horizontal deep holes and external inclined holes in the receiving end pre-reinforcement area. The longitudinal reinforcement length of the receiving end pre-reinforcement zone is 8-12m. The reinforcement range of the receiving end pre-reinforcement zone covers the soil above, below, and on both sides of the shield tunnel outline. In front of the receiving portal end wall, take 8m to 12m along the shield tunnel's direction of travel as the longitudinal reinforcement length, and expand outward from the outer outline of the shield tunnel design to the upper, lower, and left and right sides to form a full-section reinforcement range. This range is used to include the soil that may experience soil erosion, portal collapse, and local loosening during shield tunnel reception into the same grouting reinforcement body. When the strata at the receiving end are water-bearing sand, silty clay, or weak interlayers, the specific reinforcement length can be selected within the range of 8m to 12m according to the strata's self-stabilizing capacity and the receiving end's water-stopping requirements. The output results are the longitudinal reinforcement length and full-section coverage boundary of the receiving end pre-reinforcement zone. The horizontal deep holes and external inclined holes are arranged in a quincunx pattern. The external inclined holes are arranged with at least two levels of external insertion angle, and the hole depth of the external inclined holes decreases as the insertion angle increases. Adjacent horizontal deep holes are staggered in the horizontal and vertical directions so that the grout diffusion range of adjacent holes overlaps in the soil in front of the tunnel portal. At the same time, the external inclined holes are set in stages according to the external insertion angle from small to large. The external inclined holes with smaller external insertion angles extend to the deeper part of the receiving end pre-reinforcement area, while the external inclined holes with larger external insertion angles extend to the near outer edge of the receiving tunnel portal. By configuring the hole depth to decrease as the insertion angle increases, different external inclined holes cover different depths of the outer edge of the tunnel portal. The output result is the hole group coverage relationship of horizontal deep holes and external inclined holes in the receiving end pre-reinforcement area. A repeatable grouting pipe is installed inside the horizontal deep hole for re-grouting the pre-reinforced area of ​​the receiving end. Specifically, the repeatable grouting pipe is installed inside the horizontal deep hole and extends into the pre-reinforced area of ​​the receiving end along the length of the horizontal deep hole. An interface for connecting grouting equipment is reserved at the hole opening. During construction, the corresponding repeatable grouting pipe is selected and activated according to the re-grouting needs. When the pre-reinforced area of ​​the receiving end experiences excessive grout absorption, insufficient local reinforcement, or monitoring results indicating that the reinforced area needs additional grouting after the initial grouting, grout is injected again into the same reinforcement area through the corresponding repeatable grouting pipe, thereby reinforcing the local weak parts in the pre-reinforced area of ​​the receiving end. The output result is the repeatable grouting channel of the pre-reinforced area of ​​the receiving end.

[0035] In this implementation plan, the reserved grouting area on the secondary lining end wall of the receiving station is used as the drilling working surface. Horizontal deep holes are drilled into the interlayer soil between the existing operating line tunnel structure and the arch of the newly constructed shield tunnel. These horizontal deep holes are located within the arch reinforcement area of ​​the existing line interlayer soil and extend longitudinally along the shield tunnel line. After the secondary lining construction of the receiving station is completed and grouting conditions are met, the reserved grouting area on the secondary lining end wall is used as the drilling working surface. The drilling rig is then horizontally drilled along the longitudinal direction of the shield tunnel line, aligned with the arch reinforcement area of ​​the existing line interlayer soil. This allows the horizontal deep holes to enter the interlayer soil between the existing operating line tunnel structure and the arch of the newly constructed shield tunnel. This interlayer soil is formed between the two tunnel structures affected by the shield tunnel receiving disturbance. For dynamic soil requiring restricted deformation transmission, the output results are the location and extension direction of the horizontal deep holes in the arch crown reinforcement area of ​​the existing line interlayer soil. The reserved grouting area in the secondary lining end wall of the receiving station is the drilling and grouting operation area reserved in the receiving tunnel portal end wall or the main structure of the adjacent station. The receiving tunnel portal end wall is used to determine the longitudinal positioning benchmark for the receiving end grouting construction. The working face in the main structure of the receiving well and the working face in the cross passage are used to provide space for drilling rig positioning and drilling construction. The reserved grouting area in the secondary lining end wall is used to form the hole arrangement area for the horizontal deep holes in the arch crown. The above structures or working faces cooperate with each other in construction function and jointly serve the hole layout construction of the receiving end pre-reinforcement area and the existing line interlayer soil arch crown reinforcement area.

[0036] The horizontal deep holes at the crown of the arch are constructed using a segmented drilling and grouting method. In practice, each horizontal deep hole at the crown of the arch is divided into multiple continuous grouting segments along the depth direction. The construction is carried out in a cyclical manner, drilling one grouting segment first, then grouting that segment, and then moving on to the next grouting segment. This allows the grout to diffuse in the interlayer soil segment by segment and form a solidified body segment by segment. This construction method can control the diffusion range of a single grouting in a long horizontal hole, reducing the grout leakage and local pressure concentration caused by long-distance single grouting. The output result is the segmented construction sequence of the horizontal deep holes at the crown of the arch. Each grouting section is drilled and grouted through a borehole pipe, and the grouting termination conditions within the section are determined according to the design grouting pressure, design grouting volume, and borehole return grouting status. A borehole pipe is installed at the borehole opening of the horizontal deep hole at the arch crown, and the surrounding area of ​​the borehole opening is sealed. The borehole pipe is used to limit grout leakage at the borehole opening, stabilize the borehole entrance, and serve as the connection foundation for the grouting equipment. After the drilling of each grouting section is completed, grout is injected into the grouting section through the grouting equipment connected to the borehole pipe. When the grouting section meets the set combination conditions of the design grouting pressure, design grouting volume, and borehole return grouting status, the grouting of the grouting section is stopped, and the construction of the next grouting section begins. The output result is the grouting termination judgment result of a single grouting section. After each grouting section is completed in sequence, a crown reinforcement zone is formed in the existing line interlayer soil arch reinforcement zone, which is continuously distributed along the existing line protection projection area. Each grouting section is arranged continuously along the shield tunnel line in the longitudinal direction. The grout consolidation range formed by each grouting section is connected with the grout consolidation range formed by the adjacent grouting section. After multiple grouting sections are completed, a crown reinforcement zone is formed below the existing operating line tunnel structure, which is distributed along the existing line protection projection area. This crown reinforcement zone is used to improve the integrity of the interlayer soil and reduce the transmission of shield tunneling construction disturbance to the existing operating line tunnel structure. The output result is a crown reinforcement zone continuously distributed in the existing line interlayer soil arch reinforcement zone.

[0037] In this implementation plan, the locations of horizontal deep holes, externally inserted inclined holes, and horizontal deep holes at the arch top are determined based on the relative positions of the receiving end pre-reinforcement area and the existing line interlayer soil arch top reinforcement area, the spacing of grouting holes, and the effective diffusion radius of the grout. Specifically, the receiving end pre-reinforcement area and the existing line interlayer soil arch top reinforcement area are first superimposed on the shield tunnel longitudinal and cross-sectional diagrams. Then, the effective diffusion radius of the grout is determined based on the distance between the two areas, the thickness of the interlayer soil, the type of grout, and on-site grouting tests. Finally, the locations of the horizontal deep holes, externally inserted inclined holes, and horizontal deep holes at the arch top are calculated in reverse, so that the coverage of the hole group can extend to the connection between the two areas. The effective diffusion radius of the grout refers to the effective range in which the grout can stably fill or cement the soil around the hole under the design grouting pressure and design grouting volume. The output result is the hole location arrangement used to form overlapping reinforcement. The distance between adjacent grouting holes is not greater than the sum of the effective diffusion radii of the two adjacent holes. The center distance between any two adjacent grouting holes is compared with the sum of their effective diffusion radii. When the distance between the holes is not greater than the sum of the effective diffusion radii of the two adjacent holes, it is determined that the grout diffusion ranges corresponding to the two holes can overlap. When the distance between the holes is greater than the sum of the effective diffusion radii of the two adjacent holes, the hole positions are densified or the hole depth is adjusted so that no uncovered gaps are formed between the horizontal deep holes, the externally inserted inclined holes and the horizontal deep holes at the top of the arch. The output result is the overlap judgment result between adjacent grouting holes. The effective diffusion range of the horizontal deep hole, the external inclined hole, and the arch-top horizontal deep hole extends to the overlap section between the receiving end pre-reinforcement area and the existing line interlayer soil arch-top reinforcement area; the side of the receiving end pre-reinforcement area close to the existing line interlayer soil arch-top reinforcement area and the side of the existing line interlayer soil arch-top reinforcement area close to the receiving end pre-reinforcement area are defined as the overlap section. By adjusting the end position of the horizontal deep hole, the outer edge coverage position of the external inclined hole, and the start and end positions of the arch-top horizontal deep hole, the effective diffusion range of the three types of holes enters the overlap section together. The output result is a continuous grouting overlap section between the receiving end pre-reinforcement area and the existing line interlayer soil arch-top reinforcement area. The receiving end pre-reinforcement zone and the existing line interlayer soil arch reinforcement zone are interconnected in the longitudinal and vertical directions of the shield tunnel through overlapping sections, so that the reinforcement body around the receiving portal is continuously connected with the interlayer soil reinforcement zone under the existing operating line tunnel structure. The reinforcement body around the receiving portal is formed by full-section horizontal deep hole grouting, and the interlayer soil reinforcement zone under the existing operating line tunnel structure is formed by arch top horizontal deep hole grouting. The two are connected in the longitudinal direction of the shield tunnel through overlapping sections, and a continuous support path is formed in the vertical direction from the soil around the receiving portal to the interlayer soil under the existing line. This makes the pre-grouting reinforcement body of the shield receiving section spatially continuous, and the output result is the overlapping reinforcement system between the receiving end pre-reinforcement zone and the existing line interlayer soil arch reinforcement zone.

[0038] S4. When the outer periphery of the shield shell enters the overlap range, mud-resistant material is injected into the outer side of the shield shell through the radial grouting holes of the tunnel boring machine to form a filling area around the shield shell.

[0039] Specifically, the overlapping range determined by S1 is used as the spatial trigger range for injecting the mud-effect material. Real-time tunneling mileage, shield length, shield attitude, and shield tail position records of the tunnel boring machine (TBM) are used as location judgment data. When the outer periphery of the shield enters the area jointly covered by the existing line protection projection zone and the receiving end influence zone, the radial grouting holes of the TBM are activated to inject the mud-effect material into the outer side of the shield. This allows the mud-effect material to fill the instantaneous relaxation space between the outer side of the shield and the surrounding soil. The output results are the mud-effect material injection start position within the overlapping range and the filling object around the shield. In this embodiment, the mud-effect material refers to a pumpable slurry material used for filling the outer periphery of the shield shell, reducing friction, stopping water, and stabilizing the surrounding soil. After injection, it can enter the gap between the outer side of the shield and the soil, forming a temporary filling layer when the TBM passes through the overlapping range of the existing line protection projection zone and the receiving end influence zone. This temporary filling layer is used to reduce soil relaxation, groundwater channel formation, and interlayer soil disturbance transmission during shield passage. The output results are the technical meaning and functional boundary of the mud-effect material. In this embodiment, the shield formed by the mud-effect material... The surrounding filling area mainly serves to fill, reduce friction, stop water, and buffer disturbances during the overlap of the shield shell. Its material properties may differ from those of the receiving end pre-reinforcement area formed by cement-based grout consolidation, the existing line interlayer soil arch reinforcement area, and the segment wall back reinforcement area. The surrounding filling area of ​​the shield shell connects the pre-reinforcement body with the subsequent segment wall back reinforcement grouting body through continuous spatial connection, forming a continuous injection filling and reinforcement system, rather than requiring the slurry material itself to form a permanently consolidated reinforcement body with the same properties as the cement grout.

[0040] In this implementation plan, a mud-controlling material preparation and injection device is installed on the tunnel boring machine trailer. Specifically, the mud-controlling material preparation device, mixing and storage device, delivery pump, injection pipeline and pressure detection device are arranged on the tunnel boring machine trailer, and the injection pipeline is connected to the radial grouting hole of the tunnel boring machine. The mud-controlling material is continuously supplied to the radial grouting hole of the tunnel boring machine by the preparation and injection device on the trailer during the tunnel boring machine advance, avoiding injection delay caused by temporary material transfer within the overlapping area. The output result is the supply path of the mud-controlling material from the preparation device to the radial grouting hole of the tunnel boring machine. When the outer periphery of the shield shell enters the overlapping range, the radial grouting holes of the tunnel boring machine are activated according to the circumferential position of the shield shell. The radial grouting holes of the tunnel boring machine are grouped according to the circumferential position of the shield shell top, shoulder, side and bottom. The current mileage of the tunnel boring machine and the shield shell length are superimposed to calculate the coverage position of the outer periphery of the shield shell in the longitudinal direction of the shield. When the calculated outer periphery of the shield shell coincides with the overlapping range, the radial grouting hole group corresponding to the overlapping part is activated, so that the mud-repellent material is preferentially applied to the outer periphery of the shield shell jointly controlled by the existing line protection projection area and the receiving end influence area. The output result is the activation order of the radial grouting holes grouped according to the circumferential position of the shield shell. First, inject grouting material into the top and shoulder of the shield, then inject it into the sides. After the outer perimeter of the shield enters the overlapping area, first open the radial grouting holes corresponding to the top and shoulder of the shield to allow the grouting material to preferentially enter the areas above and on the upper side of the shield that are prone to soil relaxation and settlement transmission. Then open the radial grouting holes corresponding to the sides of the shield to supplement and fill the outer perimeter space on both sides of the shield with grouting material. If the shield attitude or injection pressure indicates that the local absorption is too large, then supplement the corresponding circumferential hole group. The injection process outputs the sequence of mud-effect material injection at the top, shoulder, and sides of the shield. During the mud-effect material injection, the activation of the radial grouting holes of the tunnel boring machine (TBM) is synchronized with the TBM's advance. The TBM operator determines the starting point of the shield's outer perimeter entering the overlapping range and the ending point of leaving the overlapping range based on the TBM's advance mileage. Within this range, mud-effect material injection is maintained to ensure that the outer perimeter of the shield is always supported by the filling medium during the passage of the overlapping range. The output is the synchronous control relationship between mud-effect material injection and the TBM's advance mileage. The injection volume of the mud-repellent material is 1.1-1.5 times the theoretical void volume of the shield shell's outer perimeter. Specifically, the annular void area of ​​the shield shell's outer perimeter is first determined based on the shield shell's outer diameter and the excavation profile of the newly constructed shield tunnel. Then, the annular void area of ​​the shield shell's outer perimeter is multiplied by the shield tunnel's advance length to obtain the theoretical void volume of the shield shell's outer perimeter. This is then verified in conjunction with the ground absorption within the overlapping area. Finally, this theoretical void volume of the shield shell's outer perimeter is multiplied by an injection coefficient of 1.1 to 1.5 to obtain the target injection volume of the mud-repellent material. The injection coefficient is used to compensate for ground absorption and localized... The loss of infiltration and injection pipelines ensures that the actual filling range of the mud-effect material can cover the outer periphery of the shield shell, and the output result is the target injection volume of the mud-effect material. Among them, the annular void area of ​​the outer periphery of the shield shell is obtained by subtracting the outer periphery area of ​​the shield shell from the excavation outline area of ​​the newly built shield tunnel. When the equivalent circular cross section is used for calculation on site, the annular void area can be calculated based on the equivalent diameter of the excavation outline and the outer diameter of the shield shell. When a non-circular or locally over-excavated cross section is used on site, the corresponding void area can be calculated based on the measured excavation outline or the designed over-excavation outline.

[0041] The formation of the shield perimeter filling area is based on the continuous injection of mud-resistant material into the top, shoulder and sides of the shield. When the outer perimeter of the shield passes through the overlapping range, the injected mud-resistant material enters the outer side of the shield along the radial grouting holes of the tunnel boring machine and forms a circumferentially distributed filling layer between the outer perimeter of the shield and the surrounding soil. This filling layer is spatially connected with the receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area already formed in S3, so that the disturbed area when the shield passes through the overlapping range is filled in time. The output result is the shield perimeter filling area formed within the overlapping range.

[0042] S5. When the number of segments in the reinforcement zone behind the tunnel segment wall reaches the set number of rings after exiting the shield tail, reinforcement grout is injected into the reinforcement zone behind the tunnel segment wall through at least one of the grouting holes of the tunnel segment and the reserved grouting pipe, so that a reinforcement grouting body is formed in the area behind the outer wall of the tunnel segment, and a continuous overlapping grouting reinforcement system is formed between the receiving end front reinforcement zone, the existing line interlayer soil arch reinforcement zone, the shield shell perimeter filling zone and the reinforcement zone behind the tunnel segment wall.

[0043] Specifically, the reinforcement zone behind the tunnel segment wall obtained by S2 is taken as the reinforcement object, and the number of rings after the tunnel segment leaves the shield tail is taken as the starting basis. After the tunnel segment has left the shield tail constraint and has a grouting channel behind the wall, reinforcement grout is injected into the area behind the outer wall of the tunnel segment through at least one of the grouting holes of the tunnel segment and the reserved grouting pipe. The reinforcement grout fills the gap behind the wall and the local loose soil formed after the shield tail leaves, and connects with the pre-reinforced body formed by S3 and the shield shell perimeter filling area formed by S4. The output result is the reinforcement grouting start conditions and reinforcement object of the reinforcement zone behind the tunnel segment wall. The segment wall reinforcement zone refers to the space behind the tunnel segment wall located within the existing line protection projection area, the receiver's influence area, and the overlapping area, and situated between the outer wall of the tunnel segment and the surrounding soil. This area includes gaps that may form after the shield tail exits, areas where synchronous grouting is insufficient, areas where interlayer soil disturbance is transmitted, and areas sensitive to later settlement near the receiver portal end wall. During implementation, the segment ring number, shield tail position, boundary of the existing line protection projection area, and boundary of the receiver's influence area are correlated to determine the segment rings requiring reinforcement grout injection and their circumferential hole positions. The output results are the segment ring number to be reinforced and the injection hole positions within the segment wall reinforcement zone. The reserved grouting pipe is an injection fitting that is pre-installed or subsequently installed in the grouting channel of the target segment, with its inner end connected to the grouting equipment inside the segment. The connection, with its outer end extending into or connecting to the area behind the outer wall of the segment, is used to introduce reinforcing grout into the soil behind the wall that is difficult to fully fill by synchronous grouting. When the reserved grouting pipe extends into the area behind the outer wall of the segment, its extension length is determined according to the target reinforcement thickness, the location of the void behind the wall, the permeability of the stratum, and the deformation control requirements of the existing operating line. When only the segment grouting holes are used for reinforcement grouting in the reinforcement area behind the segment wall, the segment grouting holes serve as the injection channel for the reinforcing grout. When only the reserved grouting pipe is used for reinforcement grouting, the reserved grouting pipe serves as the injection channel for the reinforcing grout. When the segment grouting holes and the reserved grouting pipe are used in combination, the segment grouting holes are used for reinforcement in the area near the outer wall of the segment, and the reserved grouting pipe is used for reinforcement in deeper areas behind the wall.

[0044] In this implementation plan, after the segment in the reinforcement zone behind the shield wall has detached 3-7 rings from the shield tail, secondary deep-hole grouting is performed using at least one of the segment grouting holes or pre-reserved grouting pipes. Specifically, construction personnel confirm the number of rings the target segment has detached from the shield tail based on the shield tunneling records and segment assembly records. When the target segment has detached 3 to 7 rings from the shield tail, it is determined that the area behind the outer wall of the segment is ready for injecting reinforcement grout. Preferably, secondary deep-hole grouting begins 5 rings after detachment from the shield tail, allowing the reinforcement grout to enter the formed space behind the wall and reducing interference with the shield tail sealing and shield advancement. The output result is a secondary deep-hole grouting. The number of starting rings for secondary deep hole grouting; In this embodiment, secondary deep hole grouting is a secondary reinforcement grouting method behind the tunnel wall, relative to the synchronous grouting of the shield; When grouting is carried out using segment grouting holes, the segment grouting holes serve as injection inlets for the reinforcement grout to enter the area behind the outer wall of the segment; When grouting is carried out using reserved grouting pipes, the reserved grouting pipes extend into or connect to the area behind the outer wall of the segment, forming a deep hole injection channel for the reinforcement grout to diffuse into the deep area behind the wall; When segment grouting holes and reserved grouting pipes are used in conjunction, the segment grouting holes are used for reinforcement in the area near the outer wall of the segment, and the reserved grouting pipes are used for reinforcement in deeper areas behind the wall; The reinforcing grout uses a two-component grout. Cement-based grout and quick-setting component are prepared separately and transported through grouting equipment to at least one of the grouting holes of the tunnel segment or the reserved grouting pipe. After being mixed inside or outside the injection channel, it enters the area behind the outer wall of the tunnel segment. The two-component grout can quickly form a solid after entering the space behind the wall, which is used to fill the gap between the outer wall of the tunnel segment and the soil and to cement the surrounding loose soil. The setting time and fluidity of the two-component grout are determined according to the permeability of the stratum, groundwater conditions, grouting distance and settlement control requirements of the existing operating line. The output result is the type of reinforcing grout used for back wall reinforcement. Secondary deep hole grouting employs multiple grouting holes grouped together, with each grouting hole undergoing at least two cyclic injections. The grouting holes and reserved grouting pipes in the reinforcement zone behind the tunnel segment wall are grouped according to the segment ring number, circumferential position, and re-grouting zone. Grouting holes within the same group are injected one by one in a set order. Each grouting hole undergoes a low-pressure test injection to determine the grout absorption and the connection status behind the wall, followed by at least one supplementary injection to complete the designed reinforcement amount. By using multi-hole grouping and cyclic injection, the concentrated grouting pressure of a single hole is reduced. The output results are the grouping injection sequence and the number of cyclic injections in the reinforcement zone behind the tunnel segment wall. The grouting pressure is controlled between 0.4 and 1.2 MPa. The pressure monitoring device of the grouting equipment records the current grouting pressure of the injection channel actually in use in real time. When the grouting pressure is lower than 0.4 MPa and the injection volume per unit time is continuously too large, it indicates that there is still a strong grouting channel in the area behind the wall corresponding to the hole position. The injection can continue to be supplemented in the low-pressure circulation mode. When the grouting pressure is close to 1.2 MPa, the injection rate is reduced and it is determined whether the grouting stop condition is reached. This allows the reinforcing grout to diffuse in the area behind the outer wall of the segment without causing excessive lifting effect on the existing operating tunnel structure. The output result is the pressure control range during the injection of reinforcing grout. The designed diffusion radius of the reinforcing grout is 0.20-0.30m, ensuring an effective grouting body with a thickness of not less than 1.5m on the outer side of the tunnel segment. The designed diffusion radius of the reinforcing grout is determined based on the outer diameter of the tunnel segment, the thickness of the voids behind the wall, the formation permeability, and the test injection results. This ensures that the reinforcing grout from a single hole effectively fills the outer side of the tunnel segment within a range of 0.20m to 0.30m, and is interconnected through the diffusion ranges of multiple injection holes, forming a reinforcing grouting body with a thickness of not less than 1.5m on the outer side of the tunnel segment, which is then output. The results show the designed diffusion range and target thickness of the reinforcing grout in the reinforcement zone behind the tunnel segment wall. Among them, 0.20m to 0.30m is the effective diffusion radius of the reinforcing grout around a single tunnel segment grouting hole or a single reserved grouting pipe at the corresponding injection position, and is not the total thickness of the reinforcing grout directly formed by a single hole injection. The reinforcing grout with an effective thickness of not less than 1.5m on the outside of the tunnel segment is formed by the continuous overlap of the diffusion ranges of multiple tunnel segment grouting holes or reserved grouting pipes in the circumferential, longitudinal and back wall depth directions. Specifically, the grouting holes in the tunnel segments are used to form a near-wall reinforcement zone within the void area behind the outer wall of the tunnel segments. The reserved grouting pipes are used to introduce the reinforcing grout into the soil behind the wall further away from the outer wall of the tunnel segments to form a deep reinforcement zone. The near-wall reinforcement zone and the deep reinforcement zone are continuously connected radially on the outer side of the tunnel segments, and the diffusion range between adjacent grouting holes overlaps to form a reinforcement grout body of the target thickness on the outer side of the tunnel segments. The method for determining that the effective thickness is not less than 1.5m is as follows: taking the outer wall of the tunnel segments as the starting surface, the continuous reinforcement grout diffusion coverage range formed by the grouting holes and / or reserved grouting pipes is counted radially outward from the tunnel segments. When there are no uncovered breaks between the near-wall reinforcement zone, the deep reinforcement zone, and the diffusion range of adjacent holes, and the radial thickness of the continuous coverage range reaches more than 1.5m, it is determined that a reinforcement grout body with an effective thickness of not less than 1.5m has been formed.

[0045] In this implementation plan, the reinforcement zone behind the tunnel segment wall includes the boundary of the existing line protection projection zone near the boundary of the existing line protection projection zone, the central part of the existing line protection projection zone located in the middle of the existing line protection projection zone, and the adjacent part of the receiving tunnel portal near the end wall of the receiving tunnel portal. Specifically, the area behind the outer wall of the tunnel segment corresponding to the boundary of the existing line protection projection zone is designated as the boundary of the existing line protection projection zone, the area behind the outer wall of the tunnel segment corresponding to the middle of the existing line protection projection zone is designated as the central part of the existing line protection projection zone, and the area behind the outer wall of the tunnel segment near the end wall of the receiving tunnel portal and which is greatly affected by the receiving construction disturbance is designated as the adjacent part of the receiving tunnel portal. The output result is three re-injection zones within the reinforcement zone behind the tunnel segment wall. The grouting holes in the boundary of the existing line protection projection area, the center of the existing line protection projection area, and the area adjacent to the receiving tunnel portal are divided into arch top group, arch waist group, side wall group, and invert arch group according to the circumferential position of the segments. The grouting holes located at the top of the segments are classified into the arch top group, the grouting holes located on the upper side of the segments are classified into the arch waist group, the grouting holes located on the left and right sides of the segments are classified into the side wall group, and the grouting holes located on the lower part of the segments are classified into the invert arch group. The hole positions of each group correspond to different stress and settlement response positions in the area behind the outer wall of the segments, so that the reinforcing grout can cover the top, upper, side, and lower areas of the outer side of the segments according to the circumferential position. The output result is the circumferential grouping of the grouting holes in the reinforcing area behind the segment wall. The grouting sequence is as follows: first, reinforce the boundary of the existing line protection projection area and the area near the receiving tunnel portal; then, reinforce the center of the existing line protection projection area. First, inject reinforcing grout into the boundary of the existing line protection projection area to form a boundary reinforcement body that restricts the disorderly diffusion of grout at the edge of the existing line protection projection area. At the same time, reinforce the area near the receiving tunnel portal to improve the stability of the soil behind the outer wall of the segment near the receiving tunnel portal. Then, reinforce the center of the existing line protection projection area so that the reinforcing grout injected in the center can be connected with the reinforcing grout body in the boundary and the area near the receiving tunnel portal. The output result is the reinforcement sequence in the reinforcement area behind the segment wall, which advances from the boundary and the receiving end towards the center. At least one of the following, namely the grouting hole of the tunnel segment or the reserved grouting pipe, used to inject reinforcing grout into the reinforcement area behind the tunnel segment wall, is offset from the longitudinal injection position of the shield machine corresponding to the radial grouting hole of the tunnel machine by at least one ring length of tunnel segment; the injection position of the mud-effect material of the radial grouting hole of the tunnel machine in the longitudinal direction of the shield machine in S4 is compared with the injection position of the reinforcing grout of the tunnel segment grouting hole or the reserved grouting pipe in S5, so that the reinforcement injection position behind the tunnel segment wall is offset from the injection position of the mud-effect material in the longitudinal direction of the shield machine by at least one ring length of tunnel segment, so that the shield shell periphery filling area formed by the mud-effect material and the reinforcement body behind the tunnel segment wall formed by the reinforcing grout form a continuous coverage in the longitudinal direction, and the output result is the misalignment relationship between the injection position of the mud-effect material and the injection position of the reinforcing grout; When grouting holes and reserved grouting pipes are installed simultaneously within the same segment ring, adjacent grouting holes and reserved grouting pipes are staggered by at least one hole position in the upward direction of the segment ring. When grouting holes and reserved grouting pipes exist simultaneously within the same segment ring, the two types of injection channels are staggered along the circumferential direction of the segment, so that there is at least one hole position between adjacent injection channels. This reduces the local pressure concentration caused by repeated injection at the same circumferential position and allows the reinforcing grout to cover more of the circumferential back wall area. The output result is the circumferential staggered arrangement relationship of grouting holes and reserved grouting pipes within the same segment ring.

[0046] When the reinforcement zone behind the tunnel segment wall is reinforced only using the segment grouting hole or only using the reserved grouting pipe, only the injection channel actually used for the reinforcement grout injection is fitted with a water stop valve, the grouting head is removed, double-fast cement mortar is filled and the screw plug is sealed; when the segment grouting hole and the reserved grouting pipe are used for reinforcement grout injection at the same time, both are fitted with a water stop valve, the grouting head is removed, double-fast cement mortar is filled and the screw plug is sealed. In this implementation plan, water-stop valves are installed at the openings of the grouting holes for the tunnel segments and the reserved grouting pipes. Specifically, water-stop valves are installed at the openings of the grouting holes for the tunnel segments used for reinforcing grout injection and at the openings of the reserved grouting pipes used for reinforcing grout injection. The water-stop valves are used to keep the openings closed before the reinforcing grout is injected, to restrict backflow during the injection process, and to work with subsequent sealing structures to block the backflow channels of groundwater and grout after the injection is completed. The output result is a water-stop structure at the opening of the reinforcing grout injection channel. The grouting holes of the segments are arranged to avoid the main reinforcement of the segments. When determining the location of the grouting holes of the segments, the reinforcement diagram of the segments and the circumferential hole position design diagram of the segments are read. The area where the main reinforcement of the segments is located is taken as the avoidance area, so that the grouting holes of the segments are arranged in a position that does not pass through the main reinforcement of the segments. This ensures that the reinforcing grout injection channel is formed without weakening the load-bearing continuity of the main reinforcement of the segments. The output result is the location of the grouting holes of the segments that avoid the main reinforcement of the segments. After the reinforcement grouting is completed, the grouting head connected to the grouting hole of the segment and the reserved grouting pipe is removed, and double-fast cement mortar is filled into the grouting hole of the segment and the reserved grouting pipe; when the corresponding injection control unit reaches the stop injection condition, the water stop valve is closed first and the grouting head connected to at least one of the outer ends of the corresponding segment grouting hole and the reserved grouting pipe is removed, and then double-fast cement mortar is filled into at least one of the corresponding segment grouting hole and the reserved grouting pipe, so that the remaining channel in the hole is filled with fast-consolidating material, and the output result is the mortar sealing section in the reinforcement grout injection channel; After the quick-setting cement mortar is filled, screw plugs are installed at the outer ends of the grouting holes and reserved grouting pipes of the tunnel segments, so that the grouting holes and reserved grouting pipes form a quick-setting cement mortar sealing section and a screw plug sealing section from the inside to the outside. After the quick-setting cement mortar has initially set and has the sealing strength, the screw plugs are installed at the outer ends of at least one of the corresponding grouting holes and reserved grouting pipes, so that the inside of the channel is formed by the quick-setting cement mortar forming an inner sealing section, and the outside of the channel is formed by the screw plug forming an outer sealing section. The two together seal the reinforcing grout injection channel and reduce the risk of leakage in the later stage. The output result is a composite sealing structure of the grouting holes and reserved grouting pipes.

[0047] Finally, in this implementation, the full-section horizontal deep hole grouting and arch top horizontal deep hole grouting in S3, the injection of mud-effect material in S4, and the injection of reinforcing grout in S5 are all controlled by the injection control unit. In specific implementation, the horizontal deep holes, external inclined holes, and arch top horizontal deep holes in S3, the shield machine radial grouting holes in S4, and the segment grouting holes and reserved grouting pipes in S5 are each used as control objects that can independently record the injection pressure and injection volume. The injection operation of each control object is judged separately to stop injection, so that the injection end of pre-reinforcement, shield perimeter filling, and segment wall reinforcement has a recordable control basis. The output result is the injection stop control object of various injection operations.

[0048] The injection control unit represents a single injection operation for a single grouting hole. When the horizontal deep hole at the crown is constructed using segmented drilling and segmented grouting, a single grouting segment within a single grouting hole serves as an injection control unit. For full-section horizontal deep hole grouting, mud-effect material injection, and reinforcing grout injection, a single continuous injection operation of a grouting hole serves as an injection control unit. For segmented drilling and segmented grouting of the horizontal deep hole at the crown, a grouting segment within a grouting hole serves as an injection control unit. Each injection control unit records the current injection pressure, injection volume per unit time, and cumulative injection volume. For full-section horizontal deep hole grouting in S3, horizontal deep hole grouting at the crown, and reinforcing grout injection in S5, the corresponding injection control unit also records the grout return status at the borehole opening, and the output result is the stop-injection determination record for each injection control unit.

[0049] The full-section horizontal deep hole grouting in S3, the horizontal deep hole grouting at the crown, and the reinforcing grout injection in S5 also combine the grout return status at the borehole opening to determine the grouting stop status. Specifically, the grout return status at the borehole opening refers to the continuous return of grout from the corresponding grouting hole, borehole pipe, segment grouting hole, or reserved grouting pipe opening. When the grout return at the borehole opening continues to reach the set detection cycle, it indicates that the grout in the corresponding injection control unit has formed effective filling in the soil around the borehole or the area behind the outer wall of the segment. This, along with the current injection pressure, the injection volume per unit time, and the cumulative injection volume, serves as the basis for judging the grouting stop. The output result is the grouting stop status judgment result obtained by combining the grout return status at the borehole opening. When the settlement change value of the existing operating line reaches the preset suspension threshold, the injection control unit currently under construction is suspended. The settlement change value of the existing operating line is obtained from settlement monitoring points deployed on the tunnel structure, track structure, or ballast structure of the existing operating line. The preset suspension threshold is determined based on the settlement warning value of the existing operating line. When the monitored settlement change value reaches the preset suspension threshold, the currently ongoing full-section horizontal deep hole grouting, arch crown horizontal deep hole grouting, mud-effect material injection, or reinforcement grout injection is suspended. The injection pressure and injection volume of adjacent injection control units are then checked, and the results are output. The result is a pause control triggered by the settlement change value of the existing operating line. In specific monitoring and control, the settlement change value of the existing operating line is one of the vertical deformation change values ​​of the existing operating line. When the protection standard of the existing operating line is set with both heave control value and differential deformation control value, the heave change value and differential deformation change value are also collected simultaneously. When any of the settlement change value, heave change value and differential deformation change value reaches the corresponding preset pause threshold, the injection control unit currently under construction is paused, and the injection pressure, injection volume per unit time and cumulative injection volume of the adjacent injection control unit are checked.

[0050] In one optional implementation, for the mud-effect material injection in S4, the injection of the corresponding injection control unit is stopped when at least two of the following conditions are met: the current injection pressure reaches the upper limit of the design pressure, the injection volume per unit time is lower than the set lower limit of the injection volume for two consecutive detection cycles, and the cumulative injection volume reaches the upper limit of the design injection volume. For the full-section horizontal deep hole grouting and arch-top horizontal deep hole grouting in S3 and the reinforcing grout injection in S5, the corresponding injection is stopped when at least three of the following conditions are met: the current injection pressure reaches the upper limit of the design pressure, the injection volume per unit time is lower than the set lower limit of the injection volume for two consecutive detection cycles, the cumulative injection volume reaches the upper limit of the design injection volume, and the grout return at the borehole continues for one detection cycle. Injection into the control unit; when the settlement change value of the existing operating line reaches the preset suspension threshold, the injection control unit currently under construction is suspended. The preset suspension threshold is 80% to 90% of the settlement warning value of the existing operating line. The output result is the suspension and suspension judgment result of the grouting reinforcement process of the shield receiving section passing under the existing line; when the special protection plan for the existing operating line specifies both the uplift warning value and the differential deformation warning value, the suspension threshold corresponding to the uplift change value and the differential deformation change value can also be determined according to 80% to 90% of their respective warning values; when the suspension thresholds of different monitoring items are inconsistent, the monitoring item that first reaches the suspension threshold is used as the trigger condition for suspending the current injection control unit.

[0051] Through the execution of S5 above, the reinforcing grout forms a reinforcing grout body in the area behind the outer wall of the tunnel segment. The reinforcing grout body and the shield perimeter filling area formed in S4 are staggered and connected in the direction of shield advancement. It also forms a continuous overlap with the receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area formed in S3. This makes the area around the receiving end portal, the interlayer soil under the existing operating line tunnel structure, the outer perimeter space of the shield, and the area behind the outer wall of the tunnel segment together constitute a continuously overlapping grouting reinforcement system. The output result is a continuously overlapping grout covering the composite risk area where the shield receiving section passes under the existing line. The reinforcement system, in this embodiment, does not require the four areas to use the exact same grout material or achieve the same consolidation strength. Rather, it refers to the continuous connection between the four areas in the longitudinal and vertical directions of the shield and in the space behind the outer wall of the segment. Specifically, the receiving end pre-reinforcement area stabilizes the soil around the receiving portal; the existing line interlayer soil arch reinforcement area limits disturbance of the interlayer soil below the existing operating line; the shield shell perimeter filling area immediately fills the loose space around the shield shell during its passage; and the segment wall reinforcement area reinforces the gap behind the outer wall of the segment after the shield tail exits. These areas are sequentially connected according to the construction sequence before shield reception, during shield shell passage, and after segment exit, forming a continuously overlapping injection filling and reinforcement system.

[0052] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line, characterized in that, The method includes: S1. Determine the shield receiving section, the existing line protection projection area, and the receiving end influence area, and determine the overlap range between the existing line protection projection area and the receiving end influence area; S2. The shield receiving section is divided into a receiving end pre-reinforcement area, an existing line interlayer soil arch reinforcement area, a shield shell perimeter filling area, and a segment wall back reinforcement area; wherein, the shield shell perimeter filling area corresponds to the outer periphery of the shield shell within the overlapping range, and the segment wall back reinforcement area corresponds to the existing line protection projection area, the receiving end influence area, and the area behind the outer wall of the segment within the overlapping range. S3. Before the shield head of the tunnel boring machine enters the influence zone of the receiving end, full-section horizontal deep hole grouting is carried out in the front reinforcement zone of the receiving end, and horizontal deep hole grouting is carried out in the arch top reinforcement zone of the existing line interlayer soil, so that the front reinforcement zone of the receiving end and the existing line interlayer soil arch top reinforcement zone form an overlapping reinforcement. S4. When the outer periphery of the shield shell enters the overlapping range, mud-resistant material is injected into the outer side of the shield shell through the radial grouting holes of the tunnel boring machine to form a periphery filling area of ​​the shield shell. S5. When the segment in the reinforcement zone behind the segment wall has exited the shield tail to a set number of rings, reinforcement grout is injected into the reinforcement zone behind the segment wall through at least one of the segment grouting holes and reserved grouting pipes, so that a reinforcement grouting body is formed in the area behind the outer wall of the segment, and a continuous overlapping grouting reinforcement system is formed between the receiving end front reinforcement zone, the existing line interlayer soil arch reinforcement zone, the shield shell perimeter filling zone and the reinforcement zone behind the segment wall. A single continuous injection operation of a single grouting hole or a single reserved grouting pipe in S3, S4 and S5 is used as an injection control unit; when the horizontal deep hole at the arch is constructed using segmented drilling and segmented grouting, a single grouting segment within a single grouting hole is used as an injection control unit; each injection control unit records the current injection pressure, the injection volume per unit time and the cumulative injection volume, and the injection control units corresponding to S3 and S5 also record the grout return status at the borehole opening; For the injection of the mud-effect material in S4, the injection of the corresponding injection control unit shall be stopped when at least two of the following conditions are met: the current injection pressure reaches the upper limit of the design pressure, the injection volume per unit time is lower than the lower limit of the set injection volume for two consecutive detection cycles, and the cumulative injection volume reaches the upper limit of the design injection volume. For full-section horizontal deep hole grouting in S3, horizontal deep hole grouting at the arch crown, and reinforcing grout injection in S5, the injection of the corresponding injection control unit shall be stopped when at least three of the following conditions are met: the current injection pressure reaches the upper limit of the design pressure, the injection volume per unit time is lower than the lower limit of the set injection volume for two consecutive detection cycles, the cumulative injection volume reaches the upper limit of the design injection volume, and the grout return at the borehole continues for one detection cycle. When the settlement change value of the existing operating line reaches the preset suspension threshold, the injection control unit currently under construction is suspended and the injection pressure and injection volume of the adjacent injection control unit are checked. The preset suspension threshold is 80% to 90% of the settlement warning value of the existing operating line.

2. The grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 1, characterized in that, In S1, the shield receiving section is the construction section located in front of the receiving portal in the newly built shield tunnel. The shield receiving section covers the receiving end influence area, the existing line protection projection area, and the overlapping range. The existing line protection projection area is determined based on the outer contour of the existing operating line tunnel structure, the design axis of the new shield tunnel, the allowable deformation control value of the existing operating line, and the geological conditions. The receiving end influence zone is determined by extending along the direction of the shield tunnel, with the receiving tunnel portal end wall as the reference. The overlapping range refers to the area where the existing line protection projection area and the receiving end influence area overlap in the longitudinal and vertical directions of the shield tunnel.

3. The grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 2, characterized in that, In S3, full-section horizontal deep-hole grouting is performed on the pre-reinforcement area of ​​the receiving end, including: Using the end wall of the receiving tunnel as the reference for hole layout, horizontal deep holes and external inclined holes are drilled from the working face inside the main structure of the receiving well and the working face inside the cross passage to the receiving end pre-reinforcement area. The horizontal deep holes extend longitudinally along the shield tunnel line, and the external inclined holes extend inclinedly from the periphery of the receiving tunnel to the outer edge of the receiving end pre-reinforcement area. The longitudinal reinforcement length of the receiving end pre-reinforcement area is 8-12m, and the reinforcement range of the receiving end pre-reinforcement area covers the soil above, below and on the left and right sides of the shield tunnel outline. The horizontal deep holes and the externally inserted oblique holes are arranged in a quincunx pattern. The externally inserted oblique holes are arranged with at least two levels of external insertion angles, and the depth of the externally inserted oblique holes decreases as the external insertion angle increases. A repeatable grouting pipe is installed in the horizontal deep hole for re-grouting the pre-reinforcement zone of the receiving end.

4. The grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 3, characterized in that, In S3, horizontal deep-hole grouting is performed on the arch crown reinforcement zone of the existing line interlayer soil, including: Using the reserved grouting area of ​​the secondary lining end wall of the receiving station as the working surface for drilling, horizontal deep holes are drilled into the interlayer soil between the existing operating line tunnel structure and the arch of the newly built shield tunnel. The horizontal deep holes are located in the arch reinforcement area of ​​the existing line interlayer soil and extend longitudinally along the shield line. The horizontal deep hole at the top of the arch was constructed using segmented drilling and segmented grouting methods. Each grouting section is drilled and grouted through the borehole pipe, and the grouting termination conditions within the section are determined according to the design grouting pressure, design grouting volume, and borehole return grouting status. After each grouting section is completed in sequence, a crown reinforcement zone is formed in the existing railway line interlayer soil crown reinforcement zone, which is continuously distributed along the existing railway line protection projection area.

5. The grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 1, characterized in that, In S3, the receiving end pre-reinforcement zone and the existing line interlayer soil arch reinforcement zone are overlapped for reinforcement, including: Based on the relative position of the receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area, the grouting hole spacing and the effective diffusion radius of the grout, the hole layout positions of the horizontal deep holes, the external inclined holes and the arch horizontal deep holes are determined. The distance between adjacent grouting holes shall not exceed the sum of the effective diffusion radii of the two adjacent holes; The effective diffusion range of the horizontal deep hole, the external inclined hole and the arch horizontal deep hole extends to the overlap section between the receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area. The receiving end pre-reinforcement area and the existing line interlayer soil arch reinforcement area are connected to each other in the longitudinal and vertical directions of the shield tunnel through the overlapping section, so that the reinforcement body around the receiving portal is continuously connected to the interlayer soil reinforcement zone under the existing operating line tunnel structure.

6. The grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 1, characterized in that, In S4, a mud-repellent material is injected into the outer side of the shield shell through the radial grouting holes of the tunnel boring machine, including: Equipment for preparing and injecting mud-resistant materials is installed on the tunnel boring machine trailer; When the outer periphery of the shield shell enters the overlapping range, the radial grouting holes of the tunnel boring machine are activated in groups according to the circumferential position of the shield shell. First, inject the mud-repellent material into the top and shoulder of the shield, and then inject the mud-repellent material into the sides of the shield. The amount of the mud-repellent material injected is 1.1-1.5 times the theoretical void volume of the outer periphery of the shield.

7. A grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 6, characterized in that, In S5, reinforcing grout is injected into the reinforcement zone behind the segment wall through at least one of the segment grouting holes and reserved grouting pipes, including: After the segment in the reinforcement zone behind the segment wall is removed from the shield tail 3-7 rings, secondary deep hole grouting is carried out using at least one of the segment grouting holes and reserved grouting pipes. The reinforcing grout is a two-component grout; The secondary deep hole grouting is performed by injecting grout into multiple grouting holes in groups, with each grouting hole being injected in at least two cycles. Grouting pressure should be controlled between 0.4 and 1.2 MPa; The design diffusion radius of the reinforcing grout is 0.20-0.30m, so that a reinforcing grout body with an effective thickness of not less than 1.5m is formed on the outside of the segment.

8. The grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 7, characterized in that, The reinforcement area behind the segment wall includes the boundary part of the existing line protection projection area near the boundary of the existing line protection projection area, the central part of the existing line protection projection area located in the middle of the existing line protection projection area, and the adjacent part of the receiving tunnel door near the end wall of the receiving tunnel door. The grouting holes in the boundary of the existing line protection projection area, the center of the existing line protection projection area, and the area adjacent to the receiving tunnel portal are divided into arch top group, arch waist group, side wall group, and invert arch group according to the circumferential position of the tunnel segments. The grouting sequence is as follows: first, reinforce the boundary of the existing line protection projection area and the area near the receiving tunnel portal, and then reinforce the center of the existing line protection projection area. At least one of the segment grouting holes and reserved grouting pipes used to inject reinforcing grout into the rear reinforcement area of ​​the segment wall is offset from the shield longitudinal injection position corresponding to the radial grouting hole of the shield machine by at least one segment length. When grouting holes and reserved grouting pipes are installed simultaneously in the same segment ring, adjacent grouting holes and reserved grouting pipes shall be staggered by at least one hole position upwards in the segment ring.

9. A grouting reinforcement method for a shield tunnel receiving section passing under an existing railway line according to claim 7, characterized in that, Water-stop valves are installed at the grouting holes of the segments and the openings of the reserved grouting pipes. The grouting holes for the segments are arranged to avoid the main reinforcement bars of the segments; After the reinforcement grouting is completed, the grouting head connected to the grouting hole of the segment and the reserved grouting pipe is removed, and double-fast cement mortar is filled into the grouting hole of the segment and the reserved grouting pipe; After the double-fast cement mortar is filled, screw plugs are installed at the outer ends of the grouting holes and reserved grouting pipes of the pipe segments, so that the grouting holes and reserved grouting pipes of the pipe segments form a double-fast cement mortar sealing section and a screw plug sealing section from the inside to the outside.

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