An anti-disturbance construction structure and construction method for a subway shield tunnel passing under a high-speed railway bridge

Abstract

The invention discloses an anti-disturbance construction structure and construction method for a subway shield machine passing under a high-speed railway bridge. An isolation curtain is set between the subway tunnel and the adjacent pier, and the isolation curtain is used to reduce the impact of the subway tunnel shield construction on the high-speed railway bridge. Anti-settlement arch frames and anti-settlement piles are set between the isolation curtains, and the anti-settlement piles are fixedly connected to the anti-settlement arch frames to form an anti-settlement zone in the upper stratum of the subway tunnel. The anti-settlement zone reduces the soil pressure loss after the subway tunnel shield machine is excavated, so that more slurry can be pressurized and injected into the gap between the shield tail and the pipe segment, thereby better filling the soil loss caused by the over-excavation gap of the subway tunnel shield machine, thereby solving the adverse effect of ground settlement on the high-speed railway bridge during the construction of the subway shield machine passing under the high-speed railway bridge.

Description

Technical Field

[0001] The present invention relates to the technical field of subway shield construction, and in particular to an anti-disturbance construction structure and a construction method for a subway shield passing under a high-speed railway bridge. Background Art

[0002] With the acceleration of urban modernization and the rapid development of urban rail transit systems, there are more and more cases of subway tunnels passing under high-speed rail bridges. Since subway shield tunnel construction can cause changes in the stress field of the surrounding soil, the stress state of the adjacent high-speed rail bridge foundations can change, which in turn causes deformation of the bridge tracks. High-speed rail operates at speeds of up to 350 km / h, placing extremely strict requirements on track smoothness and settlement deformation. Currently, there have been many precedents in China where subway shield tunnels have passed under high-speed rail bridges, causing deformation of high-speed rail bridge foundations and forcing high-speed rail to be restricted. Therefore, how to ensure that subway tunnels do not affect the high-speed rail bridge foundations when passing under high-speed rail bridges is a technical challenge in the construction of subway shield tunnels under high-speed rail bridges.

[0003] In the article "Analysis on Deformation of Metro Shield Crossing High-Speed ​​Railway Bridge Pile Foundation and Research on Key Technologies", the shield tunnel excavation from Guanggu Railway Station to Drug Administration Station of Wuhan Metro Line 11 side-by-side through the 350km / h Wuhan-Guangzhou High-Speed ​​Railway beam pile foundation is taken as an example. The surrounding strata, bridge pile foundations and piers affected by the shield construction through the test section, general protection zone and core protection zone are selected as the research objects. The method of reducing the disturbance of the surrounding strata by shield tunneling is studied, and a "five-step method" shield construction technology plan is proposed. In the "five-step method" shield construction technology plan, the focus is on adjusting the shield construction parameters through the test section, cooperating with the monitoring of ground uplift and settlement data to find the optimal construction parameters for the shield machine under the high-speed railway bridge, so as to ensure the safe excavation of the subway shield tunnel under the high-speed railway bridge pile foundation, and at the same time, the deformation of the bridge pile foundation can be controlled within the safety requirements.

[0004] In the article "Analysis of the Deformation Influence of Underpass Construction on High-speed Railway Bridges Based on Earth Pressure Balance Shield", the influence of shield construction underpass of high-speed railway bridge in the Huzhuang Station-Longzi West Lake section of Zhengzhou Metro Line 12 Phase I Project on soil and high-speed railway bridge structure was studied. It was found that in the Zhengzhou area, with multi-layered geological conditions mainly composed of clay silt, silty clay and fine sand formed by the flooding of the Yellow River, and the presence of groundwater at a depth of 8.42-13.92 meters and local upper stagnant water, subway shield construction is more sensitive to ground disturbance. Although the underpass of high-speed railway bridge was prepared before construction, the ground disturbance was relatively high. The tunnel section structure was optimized, and the "five-step method" was used to optimize the shield construction parameters of the tunnel section under the high-speed railway bridge. However, the abutment still had certain longitudinal and lateral displacements. The numerical simulation result of the lateral displacement was 2.57 mm. Although the lateral displacement of the abutment was maintained within a safe range, it still had a potential impact on the long-term safe operation of the high-speed railway bridge. Therefore, how to further improve the impact of shield construction of subway tunnels under high-speed railway bridges in geologically sensitive areas on high-speed railway bridges is still a technical problem that needs to be continuously improved in the construction of subway shield tunnels under high-speed railway bridges. Summary of the Invention

[0005] In order to overcome the deficiencies in the background technology, the present invention discloses an anti-disturbance construction structure and construction method for a subway shield tunneling under a high-speed railway bridge. By setting an isolation curtain between the subway tunnel and the adjacent pier, and setting anti-settlement arch frames and anti-settlement piles between the isolation curtains, the technical problem of adverse effects of ground settlement on the high-speed railway bridge during the construction of a subway shield tunneling under a high-speed railway bridge in a geologically sensitive area is solved.

[0006] In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solutions: an anti-disturbance construction structure for a subway shield under a high-speed railway bridge, which is used to avoid disturbance to the pier of the high-speed railway bridge when the subway tunnel shield passes under the high-speed railway bridge; an isolation curtain is arranged between the subway tunnel and the adjacent pier, and anti-settlement piles are arranged in array between the isolation curtains; a number of anti-settlement arch frames are arranged in parallel on the isolation curtain, and the anti-settlement piles are fixedly connected to the anti-settlement arch frames, and the anti-settlement arch frames apply tensile stress to the anti-settlement piles to form an anti-settlement zone on the upper part of the subway tunnel; an isolation curtain is arranged between the subway tunnel and the adjacent pier, the purpose of which is to geologically isolate the subway tunnel from the pile foundation and pier of the high-speed railway bridge in space, so as to reduce the vertical settlement and lateral settlement caused by ground settlement during the subway tunnel shield construction on the pile foundation and pier of the high-speed railway bridge. axial displacement; anti-settlement piles are placed between the isolation curtains, and the anti-settlement piles are fixedly connected to the anti-settlement arch frames arranged on the isolation curtains. After the anti-settlement arch frames apply tensile stress to the anti-settlement piles, an anti-settlement zone is formed on the upper part of the subway tunnel. The anti-settlement zone reduces the soil pressure loss after the shield excavation of the subway tunnel, so that more slurry can be pressurized and injected into the gap between the shield tail and the pipe segments. The increase in pressurized grouting liquid in the gap between the shield tail and the pipe segments can better compensate for the soil loss caused by the over-excavation gap of the subway tunnel shield, thereby reducing ground settlement during subway tunnel shield construction, and correspondingly further reducing the vertical settlement and lateral displacement of the high-speed railway bridge pile foundation and pedestal caused by ground settlement, thereby solving the adverse effects on the high-speed railway bridge caused by the subway shield underpass.

[0007] Furthermore, the isolation curtain is composed of a number of overlapping low-pressure cutting rotary jet piles. The low-pressure cutting rotary jet piles are constructed using a micro-disturbance cutting, mixing and grouting system. During the construction process, a cutting and mixing drill bit is used to cut the soil and fully mix it with cement slurry to form a pile body composed of a columnar cement-soil mixture of a certain diameter in the soil. Compared with high-pressure rotary jet piles, its grouting pressure is smaller, which can avoid the huge disturbance of the pressure in the soil layer caused by high-pressure rotary jetting, reduce the impact of the isolation curtain on the pile foundation and pedestal of the high-speed railway bridge during construction, and prevent the pile foundation and pedestal from being lifted and displaced laterally: an expansion head is provided on the top of the isolation curtain, and both ends of the anti-subsidence arch are fixedly arranged on the top of the expansion head. The expansion head is used to increase the contact area between the anti-subsidence arch frame, reduce the pressure between the contact surface of the anti-subsidence arch frame and the isolation curtain, and prevent the end of the isolation curtain from rupturing due to excessive pressure.

[0008] Furthermore, a number of stress release holes are provided between the isolation curtain and the adjacent pedestal. The depth of the stress release holes is equal to that of the isolation curtain. The lower part of the stress release holes is filled with gravel and the upper layer is filled with 37 soil. Although the grouting pressure of the isolation curtain is relatively small during construction, it is composed of overlapping low-pressure cutting rotary jet piles and is densely arranged, so the total squeezing effect on the soil layer is still relatively large. After the release holes are provided, the soil squeezing disturbance toward the pile foundation and pedestal side during the construction of the isolation curtain can be released, thereby reducing the impact of the isolation curtain construction on the pile foundation and pedestal of the high-speed railway bridge, and preventing the pile foundation and pedestal from being lifted and displaced laterally.

[0009] Furthermore, a connected stress release ditch is provided on the top of the stress release hole, and the stress release ditch is backfilled with loose Panax notoginseng soil; the expansion head on the top of the isolation curtain is achieved by increasing the pressure during rotary jet grouting. The higher grouting pressure and the shallower burial depth cause the expansion head on the top of the isolation curtain to produce a significant squeezing effect on the surface soil near the ground, thereby causing the ground to uplift; after the stress release ditch is set, the stress release ditch will absorb the near-ground surface squeezing force toward the pile foundation and the pedestal side, thereby preventing the pedestal from producing lateral displacement.

[0010] Furthermore, the anti-settlement pile is a low-pressure cutting rotary jet pile, and an enlarged head is provided at the bottom of the anti-settlement pile; the grouting pressure of the low-pressure cutting rotary jet pile is relatively small, which can prevent the accumulation of excessive soil squeezing pressure between the isolation curtains during the construction of the anti-settlement pile, and avoid the isolation curtain as a whole from causing a large lateral displacement toward the pile foundation and the pedestal side, which has an adverse effect on the pile foundation and the pedestal; the enlarged head provided at the bottom of the anti-settlement pile is equivalent to a tray during anchoring, forming an anchor anchoring structure. When tensile stress is applied to the upper part of the anti-settlement pile, the anti-settlement pile anchors the soil between the isolation curtains in the upper part of the subway tunnel into an integral structure, and at the same time, the bottom of the anti-settlement pile The enlarged head at the end of the shield applies compressive stress to the soil, thereby reducing the pressure loss of the soil layer after the tunnel shield is excavated and preventing the soil above the subway tunnel from settling. Therefore, the convergence of the shield hole diameter after the shield tail moves forward during the shield construction process can be reduced, ensuring a larger gap between the shield hole and the pipe segment, so that more slurry can be pressurized and injected into the gap between the shield tail and the pipe segment to compensate for the soil loss caused by the over-excavation gap of the subway tunnel shield, thereby reducing the ground settlement caused by the subway tunnel shield construction, and correspondingly further reducing the vertical settlement and lateral displacement of the high-speed railway bridge pile foundation and abutment caused by ground settlement.

[0011] Furthermore, a number of pressure grouting holes are provided between the anti-settlement piles, through which grouting materials are pressurized and injected. When the anti-disturbance construction structure of the subway shield tunneling under the high-speed railway bridge is applied to the multi-layered geological conditions in Zhengzhou formed by the flooding of the Yellow River and mainly composed of clay silt, silty clay and fine sand, due to the extremely low cohesion of the fine sand layer (1.0-2.0 KPa), local collapse is likely to occur when the shield tail moves forward to form a shield-forming hole during the shield construction process, thereby affecting the integrity of the shell formed by the grouting between the pipe segment and the surrounding soil, and further affecting the anti-seepage performance and the stability of the pipe segment structure during the long-term use of the subway tunnel. After the grouting material is pressurized and injected through the pressure grouting holes, the soil between the isolation curtains in the upper part of the subway can form a relatively stable overall structure, thereby preventing local collapse when the shield tail moves forward to form a shield-forming hole during the shield construction process, ensuring the integrity of the shell formed by the grouting between the pipe segment and the surrounding soil, and ensuring the anti-seepage performance and structural stability of the subway tunnel during the later long-term use.

[0012] Furthermore, the anti-settlement arch frame includes a crossbeam, an arch frame, and a tensile column. The arch frame is fixedly arranged on the upper part of the crossbeam, and the tensile column is fixedly arranged between the crossbeam and the arch frame. A plurality of through holes are provided on the crossbeam.

[0013] Furthermore, threaded steel bars are provided in the isolation curtain and the anti-settlement piles, and the outer ends of the threaded steel bars are provided with connecting threads; the threaded steel bars in the isolation curtain and the anti-settlement piles pass through the through holes on the beams and are fixedly connected to the beams with pads and nuts; the anti-settlement piles can apply tensile stress to the anti-settlement piles by tightening the nuts.

[0014] A construction method for an anti-disturbance construction structure for a subway shield tunnel passing under a high-speed railway bridge comprises the following steps:

[0015] S1. Acquisition of construction parameters for underpasses under high-speed railway bridges: Before the subway tunnel passes under the high-speed railway bridge, a suitable length is selected as the shield tunneling test section based on the line direction and the ground conditions directly above the line; in the shield tunneling test section, by adjusting the shield machine construction parameters, conducting isolation curtain and anti-settlement pile experiments, and monitoring the ground uplift and settlement data, the optimal construction parameters for the shield machine underpasses under the high-speed railway bridge and the optimal construction parameters for the isolation curtain and anti-settlement piles are found, and the optimal parameters are used for the anti-disturbance construction structure underpasses under the high-speed railway bridge and the subway tunnel construction; the shield machine construction parameters include excavation speed, total thrust, cutterhead torque, mucking volume, shield tail grease, grouting material and grouting pressure; the isolation curtain and anti-settlement pile construction parameters include isolation curtain layout parameters, low-pressure cutting jet grouting pile diameter, top expansion head diameter, jet grouting pressure, slurry ratio, overlap coefficient, anti-settlement pile layout parameters, diameter, bottom expansion head diameter, jet grouting pressure, slurry ratio, pre-tension stress, and anti-settlement arch structure dimensions.

[0016] S2. Construction of anti-disturbance structure for subway shield tunneling under high-speed railway bridge: The anti-disturbance structure for subway shield tunneling under high-speed railway bridge shall be completed before the construction of shield machine under high-speed railway bridge to avoid disturbance to pile foundation and pedestal of high-speed railway bridge when subway shield tunneling under high-speed railway bridge is constructed; the construction sequence of anti-disturbance structure for subway shield tunneling under high-speed railway bridge is as follows: 1. Construction of stress relief holes; 2. Construction of isolation curtains; 3. Construction of anti-settlement piles; 4. Installation of fixed anti-settlement arch frames.

[0017] Furthermore, the grouting pressure of the isolation curtain and anti-settlement pile is 4-8MPa, the expansion head is achieved by adjusting the grouting pressure, and the grouting pressure of the expansion head is 8-20MPa; the construction order of the anti-settlement piles on the cross section of the subway tunnel is from both sides to the middle, and the construction order of the anti-settlement piles on the longitudinal section of the subway tunnel is from the middle to both sides. The above-mentioned construction order of the anti-settlement piles utilizes the first completion of the anti-settlement piles to bear the extrusion force in the soil layer, and releases a part of the soil layer extrusion force by the ground uplift between the isolation curtains and the horizontal displacement of the soil layer along the direction of the subway tunnel. While maintaining a certain extrusion pressure in the soil layer between the isolation curtains, it avoids excessive soil layer extrusion pressure generated by accumulation between the isolation curtains, thereby preventing the isolation curtain as a whole from generating a large lateral displacement toward the pile foundation and the pedestal, which has an adverse effect on the pile foundation and the pedestal.

[0018] Due to the adoption of the technical solution as described above, the present invention has the following beneficial effects: the present invention discloses an anti-disturbance construction structure and construction method for a subway shield underpassing a high-speed railway bridge, an isolation curtain is arranged between the subway tunnel and the adjacent pier, and the isolation curtain is used to reduce the impact of the subway tunnel construction on the pile foundation and pier of the high-speed railway bridge; anti-settlement arch frames and anti-settlement piles are arranged between the isolation curtains, and the anti-settlement piles are fixedly connected to the anti-settlement arch frames to form an anti-settlement zone on the upper part of the subway tunnel, and the anti-settlement zone reduces the soil pressure loss after the subway tunnel shield is excavated, so that the gap between the shield tail and the pipe segment can be pressurized to inject more slurry, better filling the soil loss caused by the over-excavation gap of the subway tunnel shield, thereby solving the technical problem of adverse effects of ground settlement on the high-speed railway bridge during the construction of the subway shield underpassing the high-speed railway bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the plan layout of the anti-disturbance construction structure for a subway shield tunnel passing under a high-speed railway bridge in Example 1;

[0020] Figure 2 Schematic cross-section of the anti-disturbance construction structure of the subway shield tunnel under the high-speed railway bridge in Example 1;

[0021] Figure 3 A cutaway enlarged schematic diagram of the anti-disturbance construction structure of a subway shield tunnel passing under a high-speed railway bridge in Example 1;

[0022] Figure 4Schematic diagram of the plan layout of the anti-disturbance construction structure for a subway shield tunnel passing under a high-speed railway bridge in Example 2;

[0023] Figure 5 A schematic cross-sectional view of the anti-disturbance construction structure of a subway shield tunnel passing under a high-speed railway bridge in Example 2;

[0024] Figure 6 A cutaway enlarged schematic diagram of the anti-disturbance construction structure of a subway shield tunnel passing under a high-speed railway bridge in Example 2;

[0025] Figure 7 Schematic diagram of the plan layout of the anti-disturbance construction structure for a subway shield tunnel passing under a high-speed railway bridge in Example 3;

[0026] Figure 8 Schematic diagram of the cross-section of the anti-disturbance construction structure of the subway shield tunnel under the high-speed railway bridge in Example 3;

[0027] Figure 9 A schematic diagram of the cross-section and enlarged structure of the anti-disturbance construction of the subway shield tunnel under the high-speed railway bridge in Example 3;

[0028] In the figure: 1. Cap; 2. Stress relief hole; 2.1. Sealing fill; 2.2. Gravel; 3. Isolation curtain; 4. Anti-settlement piles; 5. Anti-settlement arch; 5.1. Beam; 5.2. Arch; 5.3. Tensile column; 6. Subway tunnel; 7. Threaded steel bar; 8. Pressure grouting hole; 9. Stress relief ditch. DETAILED DESCRIPTION

[0029] The present invention can be explained in detail by the following examples, the purpose of which is to disclose the present invention and to protect all technical improvements within the scope of the present invention. Example 1:

[0030] See the instructions attached Figure 1-3 : A subway shield tunneling under a high-speed railway bridge anti-disturbance construction structure, used for subway tunnel 6 under the high-speed railway bridge construction, to avoid disturbance to the high-speed railway bridge pile foundation and pedestal 1; the high-speed railway bridge structure is a 32m simply supported beam bridge with a pile group foundation of 8 piles, pedestal 1 is 11.0m long, 6.0m wide, 3.0m high, with a pile foundation diameter of 1.0m, and a pile length of 45.0-48.5m; the subway tunnel line has been optimized and designed to intersect the high-speed railway bridge at an angle of 85°, with a horizontal clearance of approximately 9.8m between the high-speed railway bridge and the bridge piles, and a tunnel burial depth of approximately 15.79m (from the top of the segment to the ground) at the underpass, with the segment outer diameter of 6.20m and the inner diameter of 5.50m;

[0031] The anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge includes: two rows of isolation curtains 3 set between a subway tunnel 6 (not yet constructed) and an adjacent cap 1; 66 anti-settlement piles 4 are arranged in an array between the isolation curtains 3; 11 anti-settlement arches 5 are fixedly installed in parallel on top of the isolation curtains 3; the anti-settlement piles 4 are fixedly connected to the anti-settlement arches 5; and 11 stress relief holes 2 are also set on the outside of each of the two rows of isolation curtains 3.

[0032] Isolation Curtain 3 is composed of 50 overlapping low-pressure cutting and jet-jet grouting piles, with a total length of 15.0m. The low-pressure cutting and jet-jet grouting piles have a diameter of 400mm, a depth of 30m, an overlap length of 100mm, and a top expansion head of 600mm in diameter and 1000mm in depth. The low-pressure cutting and jet-jet grouting piles are each equipped with 32mm diameter threaded steel bars, 300mm longer than the depth of Isolation Curtain 3, and 300-350mm diameter positioning rings are welded through spokes at 3m intervals. A threaded connector is provided at the top, and the top threaded connector is protected by a plastic sleeve when the threaded steel bars are installed.

[0033] 66 anti-settlement piles 4 are arranged in a square array, spaced 1.5m apart. They are 400mm in diameter, with expanded ends 800mm in diameter and 500mm in length. The anti-settlement piles 4 adjacent to the isolation curtain 3 are 22m deep, while the remaining piles are approximately 1m from the top of the tunnel segment. The anti-settlement piles 4 are equipped with 32mm diameter threaded steel bars, 300mm longer than the depth of the anti-settlement piles 4. Locating rings with a diameter of 300mm are welded to the spokes at 3m intervals. A threaded connector is provided at the top, protected by a plastic sleeve when the threaded steel bar is installed.

[0034] The stress relief hole 2 has a diameter of 300 mm, is 1.5 m away from the isolation curtain 3, has an adjacent interval of 1.5 m, and has the same depth as the isolation curtain 3;

[0035] The anti-settlement arch 5 includes a crossbeam 5.1, an arch 5.2, and a tensile column 5.3. The arch 5.2 is a rectangular steel of 200*400*10, with a through hole processed relative to the threaded steel bars in the isolation curtain 3 and the anti-settlement pile 4. The arch 5.2 is a round steel pipe of φ165*6, bent into an arc shape; the tensile column 5.3 is a round steel pipe of φ108*4; the arch 5.2 is fixed to the crossbeam 5.1 by welding, and the tensile column 5.3 is fixed to the crossbeam 5.1 by welding. The anti-settlement arches 5 are fixed between the crossbeam 5.1 and the arch 5.2; there are 11 anti-settlement arches 5, both ends of which are set on the top of the isolation curtain 3, the threaded steel bars pass through the through holes of the crossbeam 5.1 and extend to the upper part of the crossbeam 5.1, and a 200*200*12 pad is set on the upper part of the crossbeam 5.1. The anti-settlement arches 5 are fixedly connected to the isolation curtain 3 with nuts, and the connecting nuts of the anti-settlement piles 4 are temporarily kept loose; the adjacent anti-settlement arches 5 After the fixation is completed, the arch frame 5.2 is welded and fixed with a horizontal connecting rod to prevent the anti-settlement arch frame 5 from falling sideways; after all the anti-settlement arch frames 5 are set, the connecting nuts of all the anti-settlement piles 4 are tightened with a torque of 600Nm, and an anchor-reinforced anti-settlement zone is formed on the upper part of the subway tunnel 6 through the anti-settlement piles 4. After the shield excavation of the subway tunnel, the anti-settlement arch frame 5 prevents the anti-settlement zone from settling, thereby reducing the soil pressure loss after the shield excavation of the subway tunnel 6. Therefore, the convergence of the shield hole diameter after the shield tail moves forward during the shield construction process can be reduced, ensuring a larger gap between the shield hole and the pipe segment, so that more slurry can be pressurized and injected into the gap between the shield tail and the pipe segment, compensating for the soil loss caused by the over-excavation gap of the shield in the subway tunnel 6, reducing the ground settlement during the shield construction of the subway tunnel 6, and correspondingly reducing the vertical settlement and lateral displacement of the pile foundation and the pedestal of the high-speed railway bridge caused by ground settlement.

[0036] A construction method for an anti-disturbance construction structure for a subway shield tunnel passing under a high-speed railway bridge comprises the following steps:

[0037] S1. Obtaining Construction Parameters for Underpassing the High-Speed ​​Railway Bridge: Before subway tunnel 6 passes under the high-speed railway bridge, a suitable length is selected as a shield tunneling test section based on the line direction and the ground conditions directly above the line. In this test section, by adjusting the shield machine construction parameters and conducting experiments with the isolation curtain 3 and anti-settlement piles 4, combined with monitoring ground uplift and settlement data, the optimal construction parameters for the shield machine underpassing the high-speed railway bridge, as well as the optimal construction parameters for the isolation curtain 3 and anti-settlement piles 4, are determined. The optimal parameters are used for the anti-disturbance construction structure under the high-speed railway bridge and the shield construction of subway tunnel 6.

[0038] S2. Construction of anti-disturbance structure for subway shield tunneling under high-speed railway bridge: The anti-disturbance structure for subway shield tunneling under high-speed railway bridge should be completed before the shield machine tunneling under high-speed railway bridge. The construction sequence of the anti-disturbance structure for subway shield tunneling under high-speed railway bridge is as follows: 1. Construction of stress relief holes 2; 2. Construction of isolation curtains 3; 3. Construction of anti-settlement piles 4; 4. Installation of fixed anti-settlement arches 5;

[0039] When constructing stress relief hole 2, use mud support drilling technology (auger drilling technology is prohibited). After drilling, drain the mud and then fill with gravel with a particle size of 1-2 cm. The top of stress relief hole 2 is loosely filled with 500-800 mm deep 37 soil.

[0040] The isolation curtain 3 is constructed using low-pressure cutting jet grouting piles, with the construction sequence being from the middle to both sides. When the lower section of the jet grouting pile is formed, the grouting pressure is 5 MPa, and the upper section is 8 MPa. The upper section is subjected to two to three re-groutings to eventually reach the diameter of the top expansion head and improve the strength of the top expansion head. After each low-pressure cutting jet grouting pile is formed, the threaded steel bar 7 is immediately inserted. When the threaded steel bar 7 is inserted, it is continuously struck with a steel rod to slowly reduce its vibration. When the threaded steel bar 7 is inserted into the set depth, a steel bar positioning plate is fixed on the ground with a steel chisel, and the upper threaded section of the threaded steel bar 7 is positioned by passing through the middle through hole of the steel bar positioning plate.

[0041] The anti-settling piles 4 are constructed using low-pressure cutting jet grouting. The construction sequence is from both sides to the center in the cross-section of the subway tunnel 6, and from the center to both sides in the longitudinal section. The grouting pressure during the formation of the bottom expansion head of the jet grouting piles is 12-14 MPa to achieve the desired diameter of the bottom expansion head. After each anti-settling pile 4 is formed, threaded steel bars 7 are immediately inserted. During the insertion of the threaded steel bars 7, they are continuously struck with steel rods to slowly reduce their vibration. Once the threaded steel bars 7 are inserted to the desired depth, a steel bar positioning plate is fixed to the ground using a steel chisel. The threaded section at the upper end of the threaded steel bar 7 is inserted through the central through-hole of the steel bar positioning plate for positioning.

[0042] After the construction of the isolation curtain 3 and the anti-settlement piles 4 is completed and the strength reaches the design value, the steel bar positioning plate is removed, and a shallow foundation pit with a depth of 0.5m is excavated between the isolation curtains 3 to expose the top ends of the construction isolation curtains 3 and the anti-settlement piles 4; 0.4m of the top end of the isolation curtain 3 and 0.5m of the top end of the anti-settlement piles 4 are chiseled off, the plastic sleeve of the threaded connection head on the top of the threaded steel bar is removed, and then the anti-settlement arch frames 5 are erected one by one; both ends of the anti-settlement arch frame 5 are set at the top of the isolation curtain 3, and the threaded steel bar passes through the through hole of the beam 5.1 and extends to the upper part of the beam 5.1. A 200*200*12 pad is set on the upper part of the beam 5.1. First, the anti-settlement arch frame 5 is fixedly connected to the isolation curtain 3 with nuts, and the connecting nuts of the anti-settlement piles 4 are temporarily kept loose; after the adjacent anti-settlement arch frames 5 are fixed, the arch frames 5.2 are tightened with horizontal connecting rods The anti-settlement arches 5 are connected and fixed by welding to prevent the anti-settlement arches 5 from falling sideways; after all the anti-settlement arches 5 are set up, the connecting nuts of all the anti-settlement piles 4 are tightened with a torque of 600Nm, and an anchor-reinforced anti-settlement zone is formed on the upper part of the subway tunnel 6 through the anti-settlement piles 4; after the shield excavation of the subway tunnel, the anti-settlement arches 5 prevent the anti-settlement zone from settling, reduce the soil pressure loss after the shield excavation of the subway tunnel 6, and reduce the convergence of the shield hole diameter after the shield tail moves forward during the shield construction of the subway tunnel 6, so as to ensure that there is a larger gap between the shield hole and the pipe segment, so that more slurry can be pressurized and injected into the gap between the shield tail and the pipe segment, thereby compensating for the soil loss caused by the over-excavation gap of the shield in the subway tunnel 6, reducing the ground settlement during the shield construction of the subway tunnel 6, and correspondingly reducing the vertical settlement and lateral displacement of the pile foundation and the pedestal of the high-speed railway bridge caused by ground settlement. Example 2:

[0043] See the instructions attached Figure 4-6 If the thickness of the fine sand layer in the upper stratum of the subway tunnel 6 is too great, grouting holes 8 are arranged in an array between the anti-settling piles 4, and grouting material is pressurized and injected into the stratum through the grouting holes 8. After the grouting material is pressurized and injected into the grouting holes, the soil between the isolation curtains 3 above the subway can form a relatively stable overall structure, preventing local collapse when the shield tail moves forward during shield construction and forming a hole. This ensures the integrity of the shell formed by grouting between the pipe segments and the surrounding soil, thereby ensuring the anti-seepage performance and structural stability of the subway tunnel during long-term use. Example 3:

[0044] See the instructions attached Figure 7-9 If the isolation curtain 3 is less than 6m away from the foundation 1, a stress relief trench 9 is set at the top of the stress relief hole 2. The stress relief trench 9 is 0.6m wide and 0.5m deep. During construction, the stress relief trench 9 is first excavated, and then the stress relief hole 2 is constructed at the bottom of the stress relief trench 9. After the construction of the stress relief hole 2 is completed, the stress relief trench 9 is backfilled with 0.4m deep Sanqi soil, and the surface is covered with 0.1m backfill soil.

[0045] The parts not described in detail in this invention are prior art.

[0046] Those skilled in the art should understand that they can implement variations by combining the prior art and the above embodiments. Such variations do not affect the essence of this solution and are not described in detail here.

[0047] It should be understood that this solution is not limited to the specific implementation methods described above. The structures and construction methods not described in detail should be understood to be implemented in a common manner in the art. Any person skilled in the art can, without departing from the scope of the technical solution of this solution, use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of this solution, or modify it into an equivalent embodiment with equivalent changes, without affecting the essence of this solution. Therefore, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of this solution without departing from the content of the technical solution of this solution shall still fall within the scope of protection of the technical solution of this solution.

Claims

1. A subway shield underpass under a high-speed railway bridge anti-disturbance construction structure, used for shield construction of a subway tunnel (6) under a high-speed railway bridge to avoid disturbance to the pile foundation and pedestal (1) of the high-speed railway bridge; its characteristics are: An isolation curtain (3) is provided between the subway tunnel (6) and the adjacent pier (1), and anti-settlement piles (4) are arranged in array between the isolation curtains (3); a plurality of anti-settlement arches (5) are provided in parallel on the isolation curtains (3), the anti-settlement piles (4) are fixedly connected to the anti-settlement arches (5), and the anti-settlement arches (5) apply tensile stress to the anti-settlement piles (4), thereby forming an anti-settlement zone on the upper part of the subway tunnel (6); The isolation curtain (3) is composed of a plurality of overlapping low-pressure cutting jet-jet piles. An expansion head is provided on the top of the isolation curtain (3). Both ends of the anti-settlement arch frame (5) are fixedly arranged on the top of the expansion head.

2. The anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to claim 1 is characterized by: A plurality of stress release holes (2) are provided between the isolation curtain (3) and the adjacent support platform (1); the depth of the stress release holes (2) is equal to that of the isolation curtain (3).

3. The anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to claim 2 is characterized by: A communicating stress release groove (9) is provided at the top of the stress release hole (2).

4. The anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to claim 1 is characterized by: The anti-settling pile (4) is a low-pressure cutting jet-jet pile, and an enlarged head is provided at the bottom of the anti-settling pile (4).

5. The anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to claim 1 is characterized by: A plurality of pressure grouting holes (8) are provided between the anti-settling piles (4), and grouting material is injected under pressure through the pressure grouting holes (8).

6. The anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to claim 1 is characterized by: The anti-settling arch frame (5) comprises a crossbeam (5.1), an arch frame (5.2), and a tensile column (5.3); the arch frame (5.2) is fixedly arranged on the upper part of the crossbeam (5.1), and the tensile column (5.3) is fixedly arranged between the crossbeam (5.1) and the arch frame (5.2); and a plurality of through holes are provided on the crossbeam (5.1).

7. The anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to claim 1 is characterized by: Threaded steel bars (7) are provided in the isolation curtain (3) and the anti-settlement piles (4); the isolation curtain (3) and the anti-settlement piles (4) are fixedly connected to the anti-settlement arch frame (5) via the threaded steel bars (7).

8. A construction method for an anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to any one of items 2 or 3, characterized by: The following steps are involved: S1. Obtaining the construction parameters for the underpass of the high-speed railway bridge: Before the subway tunnel (6) passes under the high-speed railway bridge, a suitable length is selected as the shield underpass test section according to the line direction and the ground conditions directly above the line; in the shield underpass test section, by adjusting the shield machine construction parameters, and conducting isolation curtain (3) and anti-settlement pile (4) experiments, combined with monitoring the ground uplift and settlement data, the optimal construction parameters for the shield machine underpass of the high-speed railway bridge and the optimal construction parameters for the isolation curtain (3) and anti-settlement pile (4) are found, and the optimal parameters are used to carry out the anti-disturbance construction structure under the high-speed railway bridge and the subway tunnel (6) construction; S2. Construction of the anti-disturbance structure for the subway shield tunneling under the high-speed railway bridge: The anti-disturbance structure for the subway shield tunneling under the high-speed railway bridge is completed before the construction of the shield machine tunneling under the high-speed railway bridge; the construction sequence of the anti-disturbance structure for the subway shield tunneling under the high-speed railway bridge is:

1. Construction of stress release holes (2); 2. Construction of isolation curtains (3); 3. Construction of anti-settlement piles (4); 4. Installation of fixed anti-settlement arch frames (5).

9. The construction method of the anti-disturbance construction structure for a subway shield tunnel under a high-speed railway bridge according to claim 8 is characterized by: The grouting pressure of the isolation curtain (3) and the anti-settlement pile (4) is 4-8 MPa, and the expansion head is achieved by adjusting the grouting pressure, and the grouting pressure of the expansion head is 8-20 MPa; the construction order of the anti-settlement pile (4) on the cross section of the subway tunnel (6) is from both sides to the middle, and the construction order on the longitudinal section of the subway tunnel (6) is from the middle to both sides.

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