A comprehensive reinforcement construction method and structure for a tunnel underpassing embankment in inclined soft and hard strata

Abstract

The application discloses a kind of inclined soft and hard stratum tunnel underpass embankment comprehensive reinforcement construction method and structure, belong to geotechnical engineering and underground tunnel construction technical field, the present application solves the problem that current technology is difficult to effectively control stratum uneven deformation and embankment settlement in inclined soft and hard stratum tunnel underpass embankment construction, cannot guarantee embankment stability and road operation safety.The application first establishes numerical analysis model according to geological survey data, determines comprehensive reinforcement design parameter, then implements embankment slope grouting reinforcement, arch protection guide wall and underpinning pile reinforcement, pipe roof support reinforcement, tunnel excavation section small conduit and anchor rod reinforcement in sequence, simultaneously collects embankment deformation, pavement settlement and pipe roof stress data in construction process by laying monitoring element, adjusts construction parameter in real time.The application can effectively improve the overall stability of embankment, reduce pavement settlement caused by tunnel construction, guarantee normal operation of existing road, and reduce the influence of traffic load on tunnel lining structure.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering and underground tunnel construction technology, specifically involving the ground reinforcement and support construction technology for tunnels passing under existing embankments. Background Technology

[0002] In the construction of urban rail transit, municipal tunnels, and highway reconstruction and expansion projects, tunnel excavation is often required beneath existing high embankments. When the tunnel traverses an area where there is an interface between sloping, weak soil layers and hard bedrock, the mechanical properties of the strata differ significantly, posing high demands on controlling strata deformation and ensuring embankment stability during tunnel excavation. Existing reinforcement measures for such tunnel underpass projects mostly employ single-layer pipe roof pre-support or local grouting reinforcement. Some projects also utilize conventional pile foundation underpinning structures to reduce the impact of tunnel construction on existing structures.

[0003] Existing reinforcement technologies have several shortcomings when applied to tunnels passing under embankments in inclined soft and hard strata. Single methods like pre-support or localized grouting are insufficient to effectively constrain uneven deformation at the interface between the inclined soft and hard strata, and cannot prevent lateral slippage or even instability of the embankment during tunnel excavation. Conventional underpinning structures cannot effectively transfer the loads from the overlying embankment and road traffic to the deep, stable bedrock. Disturbances generated during tunnel construction are easily transmitted directly to the road structure, causing settlement and deformation exceeding control requirements, threatening normal road operation. Simultaneously, the loads transferred from the embankment also act on the tunnel lining structure, adversely affecting its long-term performance. Existing technologies struggle to form a systematic reinforcement scheme that simultaneously achieves active load transfer, coordinated stratum reinforcement, and dynamic control during construction, failing to fully meet the construction needs of tunnels passing under embankments in inclined soft and hard strata conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a comprehensive reinforcement construction method and structure for tunnels passing under embankments in inclined soft and hard strata, which solves the problem that existing technologies cannot effectively control embankment deformation and settlement during the construction of tunnels passing under embankments in inclined soft and hard strata, making it difficult to ensure embankment stability and safe road operation.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a comprehensive reinforcement structure for tunnels passing under embankments in inclined soft and hard strata, comprising:

[0007] The project includes embankment slope grouting reinforcement components, underpinning support components, advanced pipe roof support components, tunnel surrounding rock reinforcement components, and monitoring components. The embankment slope grouting reinforcement components are embedded in the strata surrounding the embankment slope and the tunnel. The underpinning support components are installed on the embankment slope at the tunnel portal section, with the lower end extending into the bedrock layer below the embankment. One end of the advanced pipe roof support components is fixedly connected to the underpinning support components, and the other end extends along the tunnel arch contour towards the tunnel excavation direction. The tunnel surrounding rock reinforcement components are embedded in the surrounding rock of the tunnel's mined section. The monitoring components are respectively installed on the embankment soil, pavement structure, and advanced pipe roof support components.

[0008] In one possible implementation, the embankment slope grouting reinforcement component includes:

[0009] The jet grouting piles, steel pipes, sleeve valve pipes, and reserved grouting pipes are provided. The jet grouting piles are installed at the toe of the embankment slope. The steel pipes and sleeve valve pipes are combined and installed in the strata within the tunnel outline. The steel pipes are installed in the strata outside the tunnel outline. The reserved grouting pipes are installed in the strata above the advanced pipe roof support components. One end of the reserved grouting pipes extends into the inclined bedrock layer.

[0010] In one possible implementation, the underpinning support assembly includes:

[0011] The structure includes a protective arch, guide wall, replacement piles, and supporting steel pipes. The protective arch and guide wall are both made of cast-in-place reinforced concrete. The protective arch is located at the beginning of the tunnel portal section, and the guide wall is located on the side of the protective arch facing the tunnel excavation direction. The bottom of both the protective arch and the guide wall is provided with concrete foundations. The upper ends of the replacement piles and supporting steel pipes are fixedly connected to the concrete foundations, and the lower ends of the replacement piles and supporting steel pipes extend into the moderately weathered bedrock layer.

[0012] In one possible implementation, the advanced pipe roof support assembly includes:

[0013] The guide steel pipe, the pipe roof steel pipe, and the reinforcing cage are provided. The guide steel pipe is fixed inside the guide wall and welded to the steel frame inside the guide wall. The pipe roof steel pipe passes through the guide steel pipe and is laid along the tunnel arch. The reinforcing cage is placed in the internal cavity of the pipe roof steel pipe.

[0014] In one possible implementation, the tunnel surrounding rock reinforcement component includes:

[0015] The tunnel includes a pre-excavated small guide pipe, a combined hollow grouting anchor bolt, and a mortar anchor bolt. The pre-excavated small guide pipe is laid along the arch contour of the tunnel's mined section. The combined hollow grouting anchor bolt is buried inside the surrounding rock of the tunnel arch. The mortar anchor bolt is buried inside the surrounding rock of the tunnel sidewall.

[0016] In one possible implementation, the monitoring component includes:

[0017] The system includes a horizontal inclinometer tube, a settlement monitoring device, and a strain acquisition device. The horizontal inclinometer tube is horizontally buried inside the embankment soil, with one end extending into the inclined bedrock surface. The settlement monitoring device is fixed to the surface of the pavement structure, and the strain acquisition device is fixed to the surface of the tube body of the advanced pipe roof support assembly.

[0018] Secondly, the present invention provides a comprehensive reinforcement method for tunnels passing under embankments in inclined soft and hard strata, comprising the following steps:

[0019] The design parameters of the comprehensive reinforcement scheme are determined based on engineering geological survey data;

[0020] Grouting reinforcement components for embankment slopes were used to reinforce the embankment slopes and the surrounding strata of tunnels.

[0021] Construction of underpinning support components on the embankment slope at the tunnel portal section, so that the lower end of the underpinning support components extends into the bedrock layer below the embankment;

[0022] Construct advanced pipe roof support components along the tunnel arch contour, and fix the advanced pipe roof support components and the underpinning support components in place;

[0023] Tunnel surrounding rock reinforcement components were used to reinforce the surrounding rock of the tunnel excavation section.

[0024] The monitoring components collect data on embankment deformation, pavement settlement, and pipe roof stress during construction, and adjust construction parameters based on the collected data.

[0025] In one possible implementation, the step of using the embankment slope grouting reinforcement component to grout the embankment slope and the surrounding strata of the tunnel involves first constructing jet grouting piles to reinforce the strata within the toe area of ​​the embankment slope, then using a combination of steel pipe and sleeve valve pipe to perform grouting reinforcement within the tunnel outline area, and using steel pipe to perform grouting reinforcement outside the tunnel outline area. At the same time, a reserved grouting pipe is installed above the area where the advanced pipe roof support component is installed, so that one end of the reserved grouting pipe extends into the inclined bedrock layer.

[0026] In one possible implementation, in the step of constructing the underpinning support assembly at the embankment slope of the tunnel portal section, the arch and guide wall are first cast in place, and then underpinning piles and supporting steel pipes are constructed at the concrete foundation positions of the arch and guide wall, so that the lower ends of the underpinning piles and supporting steel pipes extend into the interior of the moderately weathered bedrock layer. In the step of constructing the advanced pipe roof support assembly along the tunnel arch contour, the pipe roof steel pipes are laid along the tunnel arch by passing through the guide steel pipes in the guide wall, a steel cage is set inside the pipe roof steel pipes, and the pipe roof steel pipes are reinforced by grouting.

[0027] In one possible implementation, in the step of reinforcing the surrounding rock of the tunnel section using the tunnel surrounding rock reinforcement component, pre-grouting reinforcement is carried out by deploying advanced small guide pipes in the arch of the tunnel section, combined hollow grouting anchors are installed in the surrounding rock of the tunnel arch, and mortar anchors are installed in the surrounding rock of the tunnel sidewall. In the step of collecting data on embankment deformation, road surface settlement, and pipe roof stress during construction through the monitoring component, embankment soil deformation data is collected by horizontal inclinometers buried inside the embankment soil, road surface settlement data is collected by settlement monitoring devices installed on the road surface structure, and pipe roof stress data is collected by strain acquisition devices fixed on the pipe roof steel pipe. Grouting parameters and tunnel excavation construction parameters are adjusted according to the collected data.

[0028] Compared with the prior art, the advantages of this invention are as follows:

[0029] This invention utilizes the bearing structure formed by the arch support, guide wall, replacement piles, and supporting steel pipes in the replacement support assembly to directly transfer the road structure load and the overlying embankment load to the stable bedrock layer below the embankment. Compared with existing technologies that lack effective load replacement measures, this invention avoids the transfer of the overlying load through the weak soil layer to the tunnel excavation disturbance zone, reduces the impact of tunnel construction disturbance on the stability of the embankment, and simultaneously reduces the effect of road traffic load on the tunnel lining structure, thereby improving the long-term service performance of the tunnel structure.

[0030] This invention employs a synergistic reinforcement system combining embankment slope grouting reinforcement components with advanced pipe roof support components and tunnel surrounding rock reinforcement components. Compared with existing technologies that rely on single advanced support or localized grouting reinforcement, this system utilizes jet grouting piles, steel pipes, and sleeve valves within the embankment slope grouting reinforcement components to implement grouting in different areas, thereby enhancing the overall strength of the embankment slope soil. Combined with the advanced pipe roof support components deployed along the tunnel arch, this forms a continuous load-bearing and protection system. This effectively constrains uneven deformation at the interface between inclined soft and hard strata, preventing lateral slippage of the embankment during tunnel excavation. Simultaneously, it expands the coverage of stratum reinforcement and improves the stability of the surrounding rock during tunnel excavation.

[0031] The multi-component collaborative reinforcement system formed by this invention can effectively reduce road surface settlement caused by tunnel construction through the combined effect of multiple reinforcement measures. Compared with traditional reinforcement methods, it can reduce the maximum settlement of the embankment by more than 40%, meet the settlement control requirements of high-grade roads, eliminate the need to close the road during construction, ensure the continuous and normal operation of existing roads, and reduce the interference of construction on the surrounding traffic environment.

[0032] This invention, in conjunction with monitoring components, constructs a comprehensive construction control system. This system uses horizontal inclinometers, settlement monitoring devices, and strain acquisition devices to collect real-time data on embankment deformation, pavement settlement, and the stress on the steel pipes of the pipe roof. Based on the collected data, construction parameters are dynamically adjusted. Compared to existing technologies lacking dynamic control mechanisms, this system allows for timely intervention in areas with abnormal deformation during construction by using pre-reserved grouting pipes for supplementary grouting, forming a closed-loop construction control system. This further enhances the safety and stability of the construction process. Simultaneously, it allows for flexible adjustment of reinforcement parameters according to changes in geological conditions, better adapting to different inclination angles in both soft and hard geological formations. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart illustrating the construction process of integrated reinforcement of a tunnel passing under an embankment in inclined soft and hard strata, according to an embodiment of the present invention.

[0035] Figure 2 This is a cross-sectional view of the embankment slope grouting reinforcement component layout structure according to an embodiment of the present invention;

[0036] Figure 3 This is a cross-sectional view of the arch structure of the underpinning support component according to an embodiment of the present invention;

[0037] Figure 4 This is a cross-sectional view of the guide wall structure of the underpinning support component according to an embodiment of the present invention;

[0038] Figure 5 This is a cross-sectional view of the advanced pipe roof support component layout structure according to an embodiment of the present invention;

[0039] Figure 6 This is a cross-sectional view of the tunnel surrounding rock reinforcement component layout structure according to an embodiment of the present invention.

[0040] In the diagram: 1. Grouting of steel pipes on slope; 1-1. Reserved grouting holes; 2. Arch protection; 3. Replacement piles; 4. Guide wall; 5. Pipe roof support; 6. Anchor reinforcement. Detailed Implementation

[0041] 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 this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0042] Example:

[0043] It should be noted that the terms "comprising" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0044] See Figures 1 to 6 This embodiment provides a comprehensive reinforcement structure for tunnels passing under embankments in inclined soft and hard strata, including:

[0045] The project includes embankment slope grouting reinforcement components, underpinning support components, advanced pipe roof support components, tunnel surrounding rock reinforcement components, and monitoring components. The embankment slope grouting reinforcement components are embedded in the strata surrounding the embankment slope and the tunnel. The underpinning support components are installed on the embankment slope at the tunnel portal section, with the lower end extending into the bedrock layer below the embankment. One end of the advanced pipe roof support components is fixedly connected to the underpinning support components, and the other end extends along the tunnel arch contour towards the tunnel excavation direction. The tunnel surrounding rock reinforcement components are embedded in the surrounding rock of the tunnel's mined section. The monitoring components are respectively installed on the embankment soil, pavement structure, and advanced pipe roof support components.

[0046] Specifically, the inclined soft-hard strata can be a composite stratum in which weak soil layers and hard bedrock are distributed at an incline, with obvious soft-hard interfaces within the strata; the embankment slope grouting reinforcement components can be a combination of grouting components embedded in the strata to enhance the strength of the embankment slope soil; the underpinning support components can be a combination of support structures used to transfer the load of the overlying embankment and the pavement structure, which can directly transfer the load to the deep stable bedrock layer; the advanced pipe roof support components can be advanced support structures laid along the tunnel arch outline to control the deformation of the surrounding rock during tunnel excavation; the tunnel surrounding rock reinforcement components can be support and reinforcement components embedded in the surrounding rock of the tunnel cut-and-cover section to enhance the self-stabilizing capacity of the surrounding rock; and the monitoring components can be a combination of monitoring components used to collect data on embankment deformation, pavement settlement, and structural stress during construction. For example, the grouting reinforcement component for embankment slopes can form a ring-shaped grouting reinforcement zone with a width of not less than 2m, and the unconfined compressive strength of the reinforced body is greater than 0.8MPa; the lower end of the underpinning support component extends into the moderately weathered rock layer to a depth of not less than 1m; the advanced pipe roof support component can be laid out along the tunnel arch within a 150° range to form a pre-reinforcement ring for the tunnel arch.

[0047] In one possible implementation, the embankment slope grouting reinforcement component includes:

[0048] The jet grouting piles, steel pipes, sleeve valve pipes, and reserved grouting pipes are provided. The jet grouting piles are installed at the toe of the embankment slope. The steel pipes and sleeve valve pipes are combined and installed in the strata within the tunnel outline. The steel pipes are installed in the strata outside the tunnel outline. The reserved grouting pipes are installed in the strata above the advanced pipe roof support components. One end of the reserved grouting pipes extends into the inclined bedrock layer.

[0049] Specifically, jet grouting piles can be high-pressure jet grouting piles constructed using a double-pipe process, used to reinforce weak strata at the toe of embankment slopes; steel perforated pipes can be seamless steel pipes with grouting holes in the pipe wall, used for permeable grouting reinforcement of the strata; sleeve valve pipes can be grouting pipes that enable segmented grouting, used for refined grouting reinforcement within the tunnel outline area; and reserved grouting pipes can be pipes pre-embedded in the strata for supplementary grouting during construction. For example, the diameter of a jet grouting pile can be 800mm, and the pile center distance can be 550mm; within the tunnel outline area, steel perforated pipes and sleeve valve pipes are arranged in a staggered pattern, with a spacing of 1m×1m; outside the tunnel outline area, steel perforated pipes are arranged in a staggered pattern, with a spacing of 2m×2m; the diameter of a reserved grouting pipe can be 89mm, the wall thickness can be 4.5mm, and the grouting material can be ordinary silicate single-liquid grout with a water-cement ratio of 1:1 and a grouting pressure of 0.5~2.0MPa.

[0050] In one possible implementation, the underpinning support assembly includes:

[0051] The structure includes a protective arch, guide wall, replacement piles, and supporting steel pipes. The protective arch and guide wall are both made of cast-in-place reinforced concrete. The protective arch is located at the beginning of the tunnel portal section, and the guide wall is located on the side of the protective arch facing the tunnel excavation direction. The bottom of both the protective arch and the guide wall is provided with concrete foundations. The upper ends of the replacement piles and supporting steel pipes are fixedly connected to the concrete foundations, and the lower ends of the replacement piles and supporting steel pipes extend into the moderately weathered bedrock layer.

[0052] Specifically, the arch support can be a reinforced concrete arch-shaped support structure at the starting position of the tunnel portal section; the guide wall can be a reinforced concrete structure that provides guidance and positioning for the advanced pipe roof construction; the replacement pile can be a vertical load-bearing member that transfers the load of the superstructure to the bedrock layer; the supporting steel pipe can be a hot-rolled seamless steel pipe that provides vertical support for the concrete foundation; the concrete foundation can be a reinforced concrete strip foundation at the bottom of the arch support and the guide wall. For example, the concrete strength grade of the arch support and the guide wall can be C30, the radial thickness of the arch support can be 1m, and the cross-sectional dimensions of the arch support foundation can be 1.2m wide × 0.6m high; the guide wall is cast-in-place within a 150° range of the arch of the portal section, and the cross-sectional dimensions can be 1m radial × 1m longitudinal, with I18 I-beams installed inside the guide wall at 0.5m intervals; the replacement pile and the supporting steel pipe can be hot-rolled seamless steel pipes with a diameter of 146mm and a wall thickness of 6mm, and the driving depth must penetrate into the moderately weathered rock layer by no less than 1m.

[0053] In one possible implementation, the advanced pipe roof support assembly includes:

[0054] The guide steel pipe, the pipe roof steel pipe, and the reinforcing cage are provided. The guide steel pipe is fixed inside the guide wall and welded to the steel frame inside the guide wall. The pipe roof steel pipe passes through the guide steel pipe and is laid along the tunnel arch. The reinforcing cage is placed in the internal cavity of the pipe roof steel pipe.

[0055] Specifically, the guide steel pipe can be a seamless steel pipe pre-embedded inside the guide wall to provide guidance for the construction of the pipe roof steel pipe; the pipe roof steel pipe can be a hot-rolled seamless steel pipe laid along the tunnel arch to form an advanced support structure for the tunnel arch; the reinforcing cage can be a steel skeleton set inside the pipe roof steel pipe to improve the bending load-bearing capacity of the pipe roof. For example, the guide steel pipe can be a seamless steel pipe with a diameter of 186mm and a wall thickness of 3mm, welded and fixed to the I18 I-beam frame inside the guide wall; the pipe roof steel pipe can be a seamless steel pipe with a diameter of 146mm and a wall thickness of 6mm, laid along the tunnel arch within a 150° range with a radius of 6145mm, and the center distance from the pipe center to the pipe center is 30cm; the reinforcing cage can be composed of 4 steel bars with a diameter of 22mm, with fixing rings set at intervals of 1.5m, and the fixing rings can be made of steel pipe with a diameter of 42mm and a wall thickness of 3.5mm.

[0056] In one possible implementation, the tunnel surrounding rock reinforcement component includes:

[0057] The tunnel includes a pre-excavated small guide pipe, a combined hollow grouting anchor bolt, and a mortar anchor bolt. The pre-excavated small guide pipe is laid along the arch contour of the tunnel's mined section. The combined hollow grouting anchor bolt is buried inside the surrounding rock of the tunnel arch. The mortar anchor bolt is buried inside the surrounding rock of the tunnel sidewall.

[0058] Specifically, the pre-grouted guide pipe can be a seamless steel pipe installed in the arch of the tunnel's cut-and-cover section for pre-grouting reinforcement of the surrounding rock; the combined hollow grouting anchor can be a hollow anchor installed in the surrounding rock of the tunnel arch for grouting reinforcement; and the mortar anchor can be a full-length bonded anchor installed in the surrounding rock of the tunnel sidewall for rock anchoring. For example, the pre-grouted guide pipe can be a 42mm diameter, 4mm wall thickness steel pipe, with a single length of 3.5m, installed along a 150° range in the arch of the tunnel's cut-and-cover section, with a circumferential spacing of 0.3m and a longitudinal spacing of 2m; the combined hollow grouting anchor can be a 22mm diameter anchor, with a single length of 3.5m, a circumferential spacing of 1m, and a longitudinal spacing of 0.5m, installed in the surrounding rock of the tunnel arch; and the mortar anchor can be a 22mm diameter anchor, with a single length of 3.5m, a circumferential spacing of 1m, and a longitudinal spacing of 0.5m, installed in the surrounding rock of the tunnel sidewall.

[0059] In one possible implementation, the monitoring component includes:

[0060] The system includes a horizontal inclinometer tube, a settlement monitoring device, and a strain acquisition device. The horizontal inclinometer tube is horizontally buried inside the embankment soil, with one end extending into the inclined bedrock surface. The settlement monitoring device is fixed to the surface of the pavement structure, and the strain acquisition device is fixed to the surface of the tube body of the advanced pipe roof support assembly.

[0061] Specifically, the horizontal inclinometer tube can be a pipe buried inside the embankment soil to monitor the horizontal lateral deformation of the soil; the settlement monitoring component can be a monitoring component fixed to the pavement structure to monitor the vertical settlement of the pavement, such as a settlement monitoring marker or settlement monitoring pile; the strain acquisition component can be a monitoring element fixed to the surface of the pipe roof steel pipe to collect stress and strain data of the pipe roof, such as a vibrating wire strain gauge. For example, the horizontal inclinometer tube is buried entirely inside the embankment soil, with one end extending into the inclined bedrock surface; the settlement monitoring components can be arranged at 10m intervals along the roadway direction; the strain acquisition component can be affixed to the outer surface of the pipe roof steel pipe at key locations, the monitoring frequency can be set to once a day, and the settlement early warning threshold can be set to a cumulative settlement of 20mm or a daily deformation rate of 2mm / d.

[0062] See Figures 1 to 6 This embodiment also provides a comprehensive reinforcement method for tunnels passing under embankments in inclined soft and hard strata, including the following steps:

[0063] Step 1: Determine the design parameters of the comprehensive reinforcement scheme based on the engineering geological survey data.

[0064] Specifically, engineering geological survey data can be detailed survey documents containing stratigraphic distribution, physical and mechanical parameters of soil and rock, bedrock burial depth, and dip angle of the interface between soft and hard strata; design parameters can be a collection of grouting reinforcement parameters, underpinning support structure parameters, pipe roof support parameters, and surrounding rock reinforcement parameters. For example, parameters determined by simulating the entire tunnel excavation process through a 3D numerical analysis model include a jet grouting pile diameter of 800mm, a pipe roof steel pipe length of 24.965m, an underpinning pile extending into moderately weathered rock layer of no less than 1m, and a grouting pressure of 0.5~2.0MPa.

[0065] Step 2: Use embankment slope grouting reinforcement components to perform grouting reinforcement on the embankment slope and the surrounding strata of the tunnel.

[0066] Specifically, the grouting reinforcement component for embankment slope can be a combination of grouting components embedded in the stratum to enhance the strength of the embankment slope soil.

[0067] In the step of using the embankment slope grouting reinforcement component to grout the embankment slope and the surrounding strata, firstly, jet grouting piles are constructed to reinforce the strata within the toe of the embankment slope. Then, grouting reinforcement is carried out within the tunnel outline using a combination of steel pipe and sleeve valve pipe. Grouting reinforcement is carried out outside the tunnel outline using steel pipe. At the same time, a reserved grouting pipe is installed above the area where the advanced pipe roof support component is installed, so that one end of the reserved grouting pipe extends into the inclined bedrock layer.

[0068] Specifically, jet grouting piles can be high-pressure jet grouting piles constructed using a double-pipe process, used to reinforce the weak strata at the toe of embankment slopes; steel pipes can be seamless steel pipes with grouting holes in the pipe wall, used for permeable grouting reinforcement of the strata; sleeve valve pipes can be grouting pipes that can achieve segmented grouting, used for refined grouting reinforcement within the tunnel outline area; and reserved grouting pipes can be pipes pre-embedded in the strata for supplementary grouting during construction. For example, the diameter of the jet grouting pile can be 800mm, and the pile center distance can be 550mm; the steel pipes and sleeve valve pipes within the tunnel outline area are arranged in a quincunx pattern, with a spacing of 1m×1m; the steel pipes outside the tunnel outline area are arranged in a quincunx pattern, with a spacing of 2m×2m; the diameter of the reserved grouting pipe can be 89mm, the wall thickness can be 4.5mm, the grouting material can be ordinary silicate single-liquid grout, the water-cement ratio is 1:1, the grouting pressure is 0.5~2.0MPa, the plane reinforcement range is 5m on both sides of the tunnel, and the cross-sectional reinforcement range extends from 5m above the tunnel to the moderately weathered rock layer.

[0069] Step 3: Construct replacement support components on the embankment slope at the tunnel portal section, so that the lower end of the replacement support components extends into the bedrock layer below the embankment.

[0070] Specifically, the underpinning support assembly can be a combination of support structures used to transfer the load of the overlying embankment and the pavement structure, and can directly transfer the load to the deep stable bedrock layer.

[0071] In the step of constructing the underpinning support components on the embankment slope at the tunnel portal section, the arch and guide wall are first cast in place, and then the underpinning piles and supporting steel pipes are constructed at the concrete foundation positions of the arch and guide wall, so that the lower ends of the underpinning piles and supporting steel pipes extend into the interior of the moderately weathered bedrock layer.

[0072] Specifically, the arch support can be a reinforced concrete arch support structure at the starting position of the tunnel portal section; the guide wall can be a reinforced concrete structure that provides guidance and positioning for the construction of the advanced pipe roof; the replacement piles and supporting steel pipes can be hot-rolled seamless steel pipes that provide vertical support for the concrete foundation and transfer the upper load to the bedrock layer; the concrete foundation can be a reinforced concrete strip foundation at the bottom of the arch support and guide wall. For example, the concrete strength grade used for the arch support and guide wall can be C30, the radial thickness of the arch support can be 1m, and the cross-sectional dimensions of the arch support foundation can be 1.2m wide × 0.6m high; the guide wall is cast-in-place within a 150° range of the arch of the portal section, and the cross-sectional dimensions can be 1m radial × 1m longitudinal. An I18 steel frame is set inside the guide wall, arranged at a spacing of 0.5m; the replacement piles and supporting steel pipes can use hot-rolled seamless steel pipes with a diameter of 146mm and a wall thickness of 6mm, with two sets set in the transverse direction and a longitudinal spacing of 50cm. The driving depth must penetrate into the moderately weathered rock layer by no less than 1m. The steel pipes are installed in 4~6m sections, and the steel pipes are connected by threaded connections. After the pipes are installed, cement grout is injected to fill them tightly.

[0073] Step 4: Construct the advanced pipe roof support components along the tunnel arch contour, and fix the advanced pipe roof support components and the underpinning support components in place.

[0074] Specifically, the advanced pipe roof support assembly can be an advanced support structure arranged along the contour of the tunnel arch, used to control the deformation of the surrounding rock during the tunnel excavation process.

[0075] In the step of constructing the advanced pipe roof support assembly along the tunnel arch contour, the pipe roof steel pipe is laid along the tunnel arch by passing through the guide steel pipe in the guide wall, a steel cage is set inside the pipe roof steel pipe, and the pipe roof steel pipe is reinforced by grouting.

[0076] Specifically, the guide steel pipe can be a seamless steel pipe pre-embedded inside the guide wall to provide guidance for the construction of the pipe roof steel pipe; the pipe roof steel pipe can be a hot-rolled seamless steel pipe laid along the tunnel arch to form an advanced support structure for the tunnel arch; the steel cage can be a steel skeleton set inside the pipe roof steel pipe to improve the bending load-bearing capacity of the pipe roof. For example, the guide steel pipe can be a seamless steel pipe with a diameter of 186mm and a wall thickness of 3mm, which is welded and fixed to the I18 I-beam frame inside the guide wall; the pipe roof steel pipe can be a seamless steel pipe with a diameter of 146mm and a wall thickness of 6mm, which is laid out with a radius of 6145mm within a 150° range along the tunnel arch, and the center distance between the pipe centers is 30cm; the reinforcing cage can be composed of 4 steel bars with a diameter of 22mm, with fixing rings set at intervals of 1.5m, and the fixing rings can be made of steel pipe with a diameter of 42mm and a wall thickness of 3.5mm; the grouting uses cement slurry with a water-cement ratio of 1:1, a grouting pressure of 0.5~2MPa, and the cement used is 42.5 grade ordinary Portland cement.

[0077] Step 5: Use tunnel surrounding rock reinforcement components to reinforce the surrounding rock of the tunnel excavation section.

[0078] Specifically, the tunnel surrounding rock reinforcement component can be a support and reinforcement component buried inside the surrounding rock of the tunnel excavation section to improve the self-stabilizing capacity of the surrounding rock.

[0079] In the step of reinforcing the surrounding rock of the tunnel section using the tunnel surrounding rock reinforcement component, pre-grouting reinforcement is carried out by laying advanced small guide pipes in the arch of the tunnel section, combined hollow grouting anchors are installed in the surrounding rock of the tunnel arch, and mortar anchors are installed in the surrounding rock of the tunnel sidewall.

[0080] Specifically, the advanced small guide pipe can be a seamless steel pipe installed in the arch of the tunnel excavation section for pre-grouting reinforcement of the surrounding rock; the combined hollow grouting anchor can be a hollow anchor installed in the surrounding rock of the tunnel arch for grouting reinforcement; and the mortar anchor can be a full-length bonded anchor installed in the surrounding rock of the tunnel sidewall for rock anchoring. For example, advanced small guide pipes can be made of steel pipes with a diameter of 42mm and a wall thickness of 4mm, with a single length of 3.5m. They are laid out along the 150° range of the tunnel arch in the mined section, with a circumferential spacing of 0.3m and a longitudinal spacing of 2m. Cement grout is used for grouting, and the water-cement ratio is adjusted gradually from thin to thick in three levels: 1.5:1.0, 1.0:1.0, and 0.8:1.0. The grouting pressure is 0.5~1.0MPa. Combined hollow grouting anchors can be made of anchors with a diameter of 22mm, a single length of 3.5m, a circumferential spacing of 1m, and a longitudinal spacing of 0.5m, and are laid in the surrounding rock of the tunnel arch. Mortar anchors can also be made of anchors with a diameter of 22mm, a single length of 3.5m, a circumferential spacing of 1m, and a longitudinal spacing of 0.5m, and are laid in the surrounding rock of the tunnel sidewall.

[0081] Step 6: Collect data on embankment deformation, pavement settlement, and pipe roof stress during construction using monitoring components, and adjust construction parameters based on the collected data.

[0082] Specifically, the monitoring components can be a combination of monitoring components used to collect data on embankment deformation, pavement settlement, and structural stress during construction.

[0083] In the step of collecting data on embankment deformation, road surface settlement, and pipe roof stress during construction through monitoring components, embankment soil deformation data is collected by horizontal inclinometers buried inside the embankment soil, road surface settlement data is collected by settlement monitoring devices installed on the road surface structure, and pipe roof stress data is collected by strain acquisition devices fixed on the pipe roof steel pipe. Grouting parameters and tunnel excavation construction parameters are adjusted based on the collected data.

[0084] Specifically, the horizontal inclinometer tube can be a pipe buried inside the embankment soil to monitor the horizontal lateral deformation of the soil; the settlement monitoring component can be a monitoring component fixed to the pavement structure to monitor the vertical settlement of the pavement, such as a settlement monitoring marker or settlement monitoring pile; the strain acquisition component can be a monitoring element fixed to the surface of the pipe roof steel pipe to collect stress and strain data of the pipe roof, such as a vibrating wire strain gauge. For example, the horizontal inclinometer tube is buried entirely inside the embankment soil, with one end extending into the inclined bedrock surface; the settlement monitoring components can be arranged at 10m intervals along the roadway direction; the strain acquisition component can be affixed to the outer surface of the pipe roof steel pipe at key locations, the monitoring frequency can be set to once a day, and the warning threshold can be set to a cumulative settlement of 20mm or a daily deformation rate of 2mm / d.

[0085] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0086] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A comprehensive reinforcement structure for tunnels passing under embankments in inclined soft and hard strata, characterized in that, include: The project includes embankment slope grouting reinforcement components, underpinning support components, advanced pipe roof support components, tunnel surrounding rock reinforcement components, and monitoring components. The embankment slope grouting reinforcement components are embedded in the strata surrounding the embankment slope and the tunnel. The underpinning support components are installed on the embankment slope at the tunnel portal section, with the lower end extending into the bedrock layer below the embankment. One end of the advanced pipe roof support components is fixedly connected to the underpinning support components, and the other end extends along the tunnel arch contour towards the tunnel excavation direction. The tunnel surrounding rock reinforcement components are embedded in the surrounding rock of the tunnel's mined section. The monitoring components are respectively installed on the embankment soil, pavement structure, and advanced pipe roof support components.

2. The integrated reinforcement structure for tunnels passing under embankments in inclined soft and hard strata according to claim 1, characterized in that, The embankment slope grouting reinforcement component includes: The jet grouting piles, steel pipes, sleeve valve pipes, and reserved grouting pipes are provided. The jet grouting piles are installed at the toe of the embankment slope. The steel pipes and sleeve valve pipes are combined and installed in the strata within the tunnel outline. The steel pipes are installed in the strata outside the tunnel outline. The reserved grouting pipes are installed in the strata above the advanced pipe roof support components. One end of the reserved grouting pipes extends into the inclined bedrock layer.

3. The integrated reinforcement structure for tunnels passing under embankments in inclined soft and hard strata according to claim 1, characterized in that, The replacement support assembly includes: The structure includes a protective arch, guide wall, replacement piles, and supporting steel pipes. The protective arch and guide wall are both made of cast-in-place reinforced concrete. The protective arch is located at the beginning of the tunnel portal section, and the guide wall is located on the side of the protective arch facing the tunnel excavation direction. The bottom of both the protective arch and the guide wall is provided with concrete foundations. The upper ends of the replacement piles and supporting steel pipes are fixedly connected to the concrete foundations, and the lower ends of the replacement piles and supporting steel pipes extend into the moderately weathered bedrock layer.

4. The integrated reinforcement structure for tunnels passing under embankments in inclined soft and hard strata according to claim 3, characterized in that, The advanced pipe roof support assembly includes: The guide steel pipe, the pipe roof steel pipe, and the reinforcing cage are provided. The guide steel pipe is fixed inside the guide wall and welded to the steel frame inside the guide wall. The pipe roof steel pipe passes through the guide steel pipe and is laid along the tunnel arch. The reinforcing cage is placed in the internal cavity of the pipe roof steel pipe.

5. The integrated reinforcement structure for tunnels passing under embankments in inclined soft and hard strata according to claim 1, characterized in that, The tunnel surrounding rock reinforcement component includes: The tunnel includes a pre-excavated small guide pipe, a combined hollow grouting anchor bolt, and a mortar anchor bolt. The pre-excavated small guide pipe is laid along the arch contour of the tunnel's mined section. The combined hollow grouting anchor bolt is buried inside the surrounding rock of the tunnel arch. The mortar anchor bolt is buried inside the surrounding rock of the tunnel sidewall.

6. The integrated reinforcement structure for tunnels passing under embankments in inclined soft and hard strata according to claim 1, characterized in that, The monitoring components include: The system includes a horizontal inclinometer tube, a settlement monitoring device, and a strain acquisition device. The horizontal inclinometer tube is horizontally buried inside the embankment soil, with one end extending into the inclined bedrock surface. The settlement monitoring device is fixed to the surface of the pavement structure, and the strain acquisition device is fixed to the surface of the tube body of the advanced pipe roof support assembly.

7. A comprehensive reinforcement method for tunnels passing under embankments in inclined soft and hard strata, characterized in that, Includes the following steps: The design parameters of the comprehensive reinforcement scheme are determined based on engineering geological survey data; Grouting reinforcement components for embankment slopes were used to reinforce the embankment slopes and the surrounding strata of tunnels. Construction of underpinning support components on the embankment slope at the tunnel portal section, so that the lower end of the underpinning support components extends into the bedrock layer below the embankment; Construct advanced pipe roof support components along the tunnel arch contour, and fix the advanced pipe roof support components and the underpinning support components in place; Tunnel surrounding rock reinforcement components were used to reinforce the surrounding rock of the tunnel excavation section. The monitoring components collect data on embankment deformation, pavement settlement, and pipe roof stress during construction, and adjust construction parameters based on the collected data.

8. The method for comprehensive reinforcement of tunnels passing under embankments in inclined soft and hard strata according to claim 7, characterized in that, In the steps of using the embankment slope grouting reinforcement component to grout the embankment slope and the surrounding strata, firstly, jet grouting piles are constructed to reinforce the strata within the toe of the embankment slope. Then, grouting reinforcement is carried out within the tunnel outline using a combination of steel pipe and sleeve valve pipe. Grouting reinforcement is carried out outside the tunnel outline using steel pipe. At the same time, a reserved grouting pipe is installed above the area where the advanced pipe roof support component is laid, so that one end of the reserved grouting pipe extends into the inclined bedrock layer.

9. The comprehensive reinforcement method for tunnels passing under embankments in inclined soft and hard strata according to claim 7, characterized in that, In the step of constructing the underpinning support components on the embankment slope at the tunnel portal section, the arch and guide wall are first cast in place, and then underpinning piles and supporting steel pipes are constructed at the concrete foundation positions of the arch and guide wall, so that the lower ends of the underpinning piles and supporting steel pipes extend into the interior of the moderately weathered bedrock layer. In the step of constructing the advanced pipe roof support components along the tunnel arch contour, the pipe roof steel pipes are laid along the tunnel arch by passing through the guide steel pipes in the guide wall, a steel cage is set inside the pipe roof steel pipes, and the pipe roof steel pipes are reinforced by grouting.

10. The method for comprehensive reinforcement of tunnels passing under embankments in inclined soft and hard strata according to claim 7, characterized in that, In the step of reinforcing the surrounding rock of the tunnel section using tunnel surrounding rock reinforcement components, pre-grouting reinforcement is carried out by laying advanced small guide pipes in the arch of the tunnel section, combined hollow grouting anchors are installed in the surrounding rock of the tunnel arch, and mortar anchors are installed in the surrounding rock of the tunnel sidewall. In the step of collecting data on embankment deformation, road surface settlement, and pipe roof stress during construction by monitoring components, embankment soil deformation data is collected by horizontal inclinometers buried inside the embankment soil, road surface settlement data is collected by settlement monitoring devices installed on the road surface structure, and pipe roof stress data is collected by strain acquisition devices fixed on the pipe roof steel pipes. Grouting parameters and tunnel excavation construction parameters are adjusted according to the collected data.

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