Whole-ring shield segment loading system suitable for different water depth load conditions

Abstract

The invention belongs to the technical field of shield tunnel engineering, and particularly relates to a whole-ring shield segment loading system suitable for different water depth load conditions, which comprises a T-shaped loading beam, a hoop steel strand loading system, an actuator loading system and a support frame, the plurality of T-shaped loading beams are uniformly distributed on the outer circumference of the whole-ring duct piece, each T-shaped loading beam comprises a supporting beam and a trapezoidal beam, the trapezoidal beam is a prism with a trapezoidal cross section, the bottom surface of the trapezoidal beam is parallel to the axis of the whole-ring duct piece, one end of the trapezoidal beam is fixed in the middle of the supporting beam perpendicular to the trapezoidal beam, and the trapezoidal beam is fixed on the whole-ring duct piece through the hoop steel strand loading system; the supporting frame is fixed on the ground, the axis of the whole-ring duct piece is parallel to the ground and is fixed in the supporting frame through the actuator loading system, the hoop steel strand loading system provides hoop force with adjustable magnitude, and the actuator loading system provides radial force with adjustable magnitude. According to the invention, loading of the vertical whole-ring shield segment under different water depth load conditions is realized, and the actual stress of the shield segment is accurately reflected.

Description

Technical Field

[0001] The invention belongs to the technical field of shield tunnel engineering, and in particular relates to a full-ring shield segment loading system suitable for different water depth load conditions. Background Art

[0002] At present, large-scale tunnel projects at home and abroad are mainly constructed by shield method. During the excavation process, shield machines need to use shield segments to support the excavation section. Shield segments bear water pressure, soil pressure, stratum resistance, etc. Their safety performance is crucial to the entire tunnel project. Compared with small-scale tests, full-ring full-scale shield segment tests can more truly reflect the stress performance of shield segments in actual service and have broad application prospects. In actual projects, the load borne by the segments is a uniformly distributed load. It is difficult to reflect the actual working conditions of different water depth load conditions by only loading multiple concentrated forces along the radial direction, especially the large axial force and small bending moment working conditions under high water pressure load conditions.

[0003] At present, in the prototype test of shield tunnel, the tension method is adopted, and the reaction force of the tension beam is used to apply radial pressure to the shield tunnel structure to simulate the effect of soil pressure on the tunnel structure; the hoop method is adopted, and the contact pressure of the hoop anchor on the outer surface of the shield tunnel structure is used to introduce axial force into the structure to simulate the effect of water pressure on the tunnel structure. Chinese patents CN101403645B and CN211263008U both use hoop beams to apply hoop force to the segment ring to generate axial force, and use tension beams to apply radial pressure to the segment structure to generate bending moment. However, the following technical problems affect the loading test results: 1. The flat-lying loading method is adopted to place the test segment ring of the shield tunnel horizontally, which is inconsistent with the vertical placement of the shield segments in actual operations and ignores the influence of the deadweight of the shield segments; 2. The tension method requires drilling holes in the shield segments to lay tension anchor cables, which damages the shield segments, and the loading form of the tension beams is symmetrical loading, while the load on the actual tunnel structure is asymmetrical. In addition, the number of tension beams is small, and a more realistic bending moment cannot be applied; 3. The loading beams of the hoop method have different loads on both sides, which is easy to overturn. After the hoop anchor cables are tightened, they interact with the loading beams and are prone to breakage, which poses a great safety hazard. Summary of the invention

[0004] In view of this, the present invention provides a full-ring shield segment loading system suitable for different water depth load conditions. The system can realize loading of different water depth load conditions for vertical full-ring shield segments, can accurately reflect the actual stress of the shield segments, and the test process is relatively safe.

[0005] The present invention is achieved through the following technical solutions:

[0006] A whole-ring shield segment loading system suitable for different water depth load conditions comprises a T-shaped loading beam, a hoop steel strand loading system, an actuator loading system and a support frame; a plurality of T-shaped loading beams are evenly arranged on the outer circumference of the whole-ring segment, the T-shaped loading beam comprises a support beam and a trapezoidal beam, the trapezoidal beam is a prism with a trapezoidal cross section, the bottom surface is parallel to the axis of the whole-ring segment, one end of the trapezoidal beam is fixed to the middle of the support beam perpendicular to the support beam, and the trapezoidal beam is fixed to the whole-ring segment through the hoop steel strand loading system; the support frame is fixed to the ground, the axis of the whole-ring segment is parallel to the ground and fixed in the support frame through the actuator loading system, the hoop steel strand loading system is used to provide an adjustable hoop force, and the actuator loading system is used to provide an adjustable radial force.

[0007] Furthermore, a plurality of hoop steel strand loading systems are evenly arranged on the side of each trapezoidal beam, and the hoop steel strand loading system includes a steel strand, a jack and a force sensor I; the tensioning end of the steel strand is fixed on one side of the trapezoidal beam, the tensioning end of the steel strand passes through the trapezoidal beam to fit the entire ring of segments in a circumferential circle, and passes through the same trapezoidal beam again to be fixed on the other side of the same trapezoidal beam, and the end of the steel strand fixed on the other side of the same trapezoidal beam is the fixed end of the steel strand; the force sensor I and the jack are installed on the tensioning end of the steel strand, and the force sensor I is installed on the fixed end of the steel strand.

[0008] Furthermore, the actuator loading system includes an actuator, a force sensor II and an annular fixed frame, the annular fixed frame is coaxially mounted outside the entire ring of segments, multiple actuators are evenly distributed on each trapezoidal beam, each actuator is placed radially along the entire ring of segments, one end of the actuator is equipped with a force sensor II to abut against the top surface of the trapezoidal beam, and the other end of the actuator is fixed to the annular fixed frame.

[0009] Furthermore, the support frame includes an inner ring steel, a square frame and an outer steel. The square frame is mounted outside the annular fixing frame and together forms a centrally symmetrical figure. The annular fixing frame is provided with a plurality of inner ring steels evenly arranged in the annular direction. The inner ring steels are radially arranged along the radial direction of the entire ring of segments. One end of the inner ring steel is fixed to the annular fixing frame, and the other end of the inner ring steel is fixed to the square frame. The outer steel is fixed to both sides of the square frame to support the square frame.

[0010] Furthermore, the actuator loading system also includes an annular base plate, which is fixed on one side of the annular fixing frame along the axial direction of the entire ring of segments, the end faces of the entire ring of segments abut against the annular base plate, the support beam abuts against the annular base plate, and the abutting surface of the support beam is provided with a directional pulley for supporting the beam to move radially along the entire ring of segments.

[0011] Furthermore, ribs are provided at the connection between the support beam and the trapezoidal beam, and the angle between the side surface of the trapezoidal beam and the radial direction of the pipe segment is 5° to 25°.

[0012] Furthermore, elliptical holes are provided on both sides of the trapezoidal beam for the steel strands on the same trapezoidal beam to pass through.

[0013] Furthermore, inclined pads are arranged in the gaps between the steel strands and the entire ring of segments on both sides of the trapezoidal beam.

[0014] Furthermore, the steel strands are unbonded prestressed steel strands, which are used to control the load difference between the fixed end of the steel strand and the tensioned end of the steel strand within 5%.

[0015] Furthermore, rubber pads are arranged in the gaps between the plurality of steel strands between the bottom surface of the trapezoidal beam and the full ring of segments.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention adopts hoop force to simulate water pressure, radial force to simulate soil layer and stratum resistance, and takes into account the influence of the deadweight of the whole ring segment; the size of the hoop force and radial force, the number and position of T-type loading beams can be adjusted according to the load conditions, and can truly reflect the mechanical properties of the whole ring segment under different water depth load conditions; compared with the loading beam in the prior art, the trapezoidal beam cross-section of the T-type loading beam of the present invention is trapezoidal, which can reduce the damage of the hoop steel strand loading system during the experiment, and the support beam of the T-type loading beam can solve the problem of easy overturning after being stressed.

[0018] 2. The present invention adopts a T-shaped loading beam to realize the loading of the hoop steel strands and the radial actuator at the same time, which can effectively save space, and the number of hoop steel strands and actuators can be adjusted to adapt to different load conditions; the actuator does not need to drill holes in the pipe segment to lay the tension anchor cables, reducing damage to the pipe segment, and symmetrical or asymmetrical layout can be achieved by adjusting the position of the actuator and the amount of force applied.

[0019] 3. The present invention adopts an assembled support frame, which can carry out loading tests on a whole ring of vertically placed segments. One to multiple rings of shield segment test systems can be assembled according to test requirements. After the experiment, the system can be disassembled and stored, which is convenient to operate.

[0020] 4. The present invention provides anti-overturning moment through ribs, further reducing the risk of overturning of the T-type loading beam; the angle between the side of the trapezoidal beam and the radial direction of the pipe segment is 5° to 25°, so that the connection between the steel strand and the anchor has a smooth transition, which can not only ensure the good transmission of the hoop force but also reduce the breakage of the steel strand.

[0021] 5. The present invention provides a directional pulley so that the T-shaped loading beam can move radially along the segment, ensuring that the T-shaped loading beam moves radially as the entire ring of segments contracts inward after being stressed.

[0022] 6. The trapezoidal beam of the present invention is provided with an elliptical hole, and a fixed inclined pad is used to fill the gap between the steel strand near the trapezoidal beam and the entire ring of segments, thereby further preventing the steel strand from being fractured under stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the general assembly of the present invention.

[0024] Figure 2 It is a schematic diagram of the T-shaped loading beam of the present invention.

[0025] Figure 3 It is a detailed schematic diagram of the T-shaped loading beam of the present invention.

[0026] Among them, 1-T-type loading beam, 1.1-support beam, 1.2-directional pulley, 1.3-trapezoidal beam, 1.4-rib plate, 1.5-rubber pad, 1.6-elliptical hole, 2-hoop steel strand loading system, 2.1-steel strand, 2.2-anchor, 2.3-jack, 2.4-anchor pad, 2.5-force sensor I, 2.6-inclined pad, 3-actuator loading system, 3.1-actuator, 3.2-force sensor II, 3.3-annular fixing frame; 4-support frame, 4.1-inner ring steel, 4.2-square frame, 4.3-external steel, 5-full ring segment. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] The present invention provides a full-ring shield segment loading system suitable for different water depth load conditions, such as Figure 1 As shown, the system includes a T-shaped loading beam 1, a hoop steel strand loading system 2, an actuator loading system 3 and a support frame 4; multiple T-shaped loading beams 1 are evenly arranged on the outer circumference of the entire ring segment 5, and the T-shaped loading beam 1 includes a transverse support beam 1.1 and a longitudinal trapezoidal beam 1.3. The support beam 1.1 and the trapezoidal beam 1.3 are perpendicular to each other. The trapezoidal beam 1.3 is a prism with a trapezoidal cross section. The bottom surface of the trapezoidal beam 1.3 is parallel to the axis of the entire ring segment 5. The support beam 1.1 is placed along the tangent direction of the entire ring segment 5. One end of the trapezoidal beam 1.3 is fixed at the middle position of the support beam 1.1. The T-shaped loading beam 1 is connected to the entire ring segment 5 through the hoop steel strand loading system 2.

[0029] Compared with the cubic loading beam in the prior art, the trapezoidal beam 1.3 is inclined on the side, which is more conducive to the operation of the hoop steel strand loading system 2. The support beam 1.1 vertically fixed to the trapezoidal beam 1.3 effectively reduces the overturning problem of the trapezoidal beam 1.3 under the operation of the hoop steel strand loading system 2; the T-shaped loading beam 1 can adjust its number or its layout position according to the test load requirements, and can choose symmetrical layout or asymmetrical layout.

[0030] The support frame 4 is fixed on the ground, and the axis of the entire ring of segments 5 is parallel to the ground and fixed in the support frame 4 through the actuator loading system 3. The hoop steel strand loading system 2 is used to provide an adjustable hoop force, and the actuator loading system 3 is used to provide an adjustable radial force.

[0031] As an improvement, Figure 2 As shown, the hoop steel strand loading system 2 includes steel strands 2.1, jacks 2.3 and force sensors Ⅰ 2.5. Multiple sets of hoop steel strand loading systems 2 are evenly arranged on the side of each trapezoidal beam 1.3, that is, multiple sets of steel strands 2.1, jacks 2.3 and force sensors Ⅰ 2.5 can be evenly arranged on each trapezoidal beam 1.3; one end of the steel strand 2.1 is the steel strand tensioning end, and the other end is the steel strand fixed end, and the steel strand tensioning end is fixed to the trapezoidal beam 1.3 On one side, the tensioning end of the steel strand passes through the trapezoidal beam 1.3, circumferentially close to the full ring of segments 5, and passes through the same trapezoidal beam 1.3 again to be fixed on the other side of the same trapezoidal beam 1.3. The end of the steel strand 2.1 fixed on the other side of the same trapezoidal beam 1.3 is the fixed end of the steel strand; the steel strand 2.1 circumferentially does not pass through other trapezoidal beams 1.3 that it passes through, that is, the steel strand 2.1 is located at the bottom of other trapezoidal beams 1.3 and close to the outer circumference of the full ring of segments 5.

[0032] A force sensor I 2.5 and a jack 2.3 are installed at the tensioning end of the steel strand, and a force sensor I 2.5 is installed at the fixed end of the steel strand; anchor pads 2.4 and anchors 2.2 can also be installed at the tensioning end and the fixed end of the steel strand, so that the jack 2.3 can be used to tighten the annular steel strand 2.1. In this embodiment, the jack 2.3 tightens the steel strand 2.1 to apply a hoop force to the entire ring of segments 5, and the magnitude of the hoop force applied is adjusted by adjusting the tightening amplitude.

[0033] As a further improvement, the actuator loading system 3 includes several actuators 3.1, several force sensors II 3.2 and annular fixing frame 3.3. The annular fixing frame 3.3 is coaxially mounted outside the entire ring segment 5. Multiple actuators 3.1 are evenly distributed on each trapezoidal beam 1.3. The actuators 3.1 are placed radially along the entire ring segment. One end of the actuator 3.1 is equipped with a force sensor II 3.2 and abuts against the top surface of the trapezoidal beam 1.3. The other end of the actuator 3.1 is fixed to the annular fixing frame by bolts. The actuator 3.1 can apply an adjustable radial force to the entire ring segment, and the force application point of the actuator 3.1 acts on the symmetry axis of the trapezoidal beam 1.3. In this embodiment, the T-type loading beam 1 is symmetrically arranged on the entire ring segment, and the actuator loading system 3 can apply a symmetrical radial force to the entire ring segment, and can also apply an asymmetrical radial force to the entire ring segment.

[0034] As a further improvement, the support frame 4 includes an inner ring steel 4.1, a square frame 4.2 and an outer steel 4.3. The square frame 4.2 is mounted outside the fixing frame 3.3 and together forms a central symmetrical figure. A plurality of inner ring steels 4.1 are evenly arranged along the annular fixing frame. The inner ring steels 4.1 are radially arranged along the entire ring of segments. One end of the inner ring steel 4.1 is fixed to the annular fixing frame, and the other end of the inner ring steel 4.1 is fixed to the square frame 4.2. The outer steel 4.3 is fixed to both sides of the square frame 4.2 and is fixed to the ground to support the square frame 4.2. The inner ring steel 4.1, the square frame 4.2 and the outer steel 4.3 are fixedly connected by bolts; the support frame 4 can be adjusted according to the number of segments.

[0035] As a further improvement, Figure 2 As shown, ribs 1.4 are provided at the connection between the support beam 1.1 and the trapezoidal beam 1.3, and the angle between the side surface of the trapezoidal beam 1.3 and the radial direction of the pipe segment is 5° to 25°, which can make the connection between the steel strand 2.1 and the anchor 2.2 smoothly transition.

[0036] As a further improvement, Figure 2 As shown, the actuator loading system 3 also includes an annular base plate, which is vertically arranged and fixed on one side of the annular fixing frame 3.3 along the axial direction of the entire ring of segments 5. The end face of the entire ring of segments 5 abuts against the annular base plate, and the support beam 1.1 abuts against the annular base plate. The abutting surface of the support beam 1.1 and the annular base plate is provided with a directional pulley 1.2. When the entire ring of segments contracts as the steel strands are tightened, the T-shaped loading beam 1 also moves radially, and the directional pulley 1.2 ensures that the support beam 1.1 moves radially along the entire ring of segments.

[0037] As a further improvement, Figure 3 As shown, an elliptical hole 1.6 is provided on the side of the trapezoidal beam 1.3 for the steel strand 2.1 on the same trapezoidal beam 1.3 to pass through. The long slot-shaped elliptical hole 1.6 further avoids the breakage of the steel strand 2.1.

[0038] As a further improvement, Figure 3 As shown, an inclined spacer 2.6 is arranged in the gap between the steel strand 2.1 and the full ring segment 5 to ensure good transmission of the hoop force.

[0039] As a further improvement, the steel strand 2.1 uses unbonded prestressed steel strands to reduce friction along the circumferential direction, and is used to control the load difference between the fixed end of the steel strand and the tensioned end of the steel strand to within 5%. The load difference on both sides of the trapezoidal beam 1.3 is reduced, which can further reduce the risk of overturning of the trapezoidal beam 1.3.

[0040] As a further improvement, rubber pads 1.5 are arranged between the bottom surface of the trapezoidal beam 1.3 and the pipe segment and in the gaps between the plurality of steel strands 2.1. The rubber pads 1.5 can be tied to the trapezoidal beam 1.3 by thin steel wires. The rubber pads 1.5 can fill the gaps between the trapezoidal beam 1.3 and the entire ring of pipe segments 5.

[0041] The present invention adopts a T-shaped loading beam to hoop steel strands for loading to simulate water pressure and reduce the breakage of steel strands, and uses a radial actuator to load to simulate soil pressure and stratum resistance, thereby realizing asymmetric load loading, and fixing the entire ring of segments 5 through a supporting frame 4, taking into account the influence of the deadweight of the entire ring of segments 5, ensuring the integrity of the entire ring, and solving the problem that the loading beam is prone to overturning after being subjected to force, thereby greatly reducing the breakage of steel strands 2.1 during the experiment, and safely and truly reflecting the mechanical properties of the entire ring of segments 5 under different water depth load conditions.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A full-ring shield segment loading system suitable for different water depth load conditions, characterized in that: It includes a T-shaped loading beam, a hoop steel strand loading system, an actuator loading system and a support frame; a plurality of T-shaped loading beams are evenly arranged on the outer circumference of a whole ring of segments, the T-shaped loading beam includes a support beam and a trapezoidal beam, the trapezoidal beam is a prism with a trapezoidal cross section, the bottom surface is parallel to the axis of the whole ring of segments, one end of the trapezoidal beam is fixed to the middle of the support beam perpendicular to it, and the trapezoidal beam is fixed to the whole ring of segments through the hoop steel strand loading system; the support frame is fixed on the ground, the axis of the whole ring of segments is parallel to the ground and fixed in the support frame through the actuator loading system, the hoop steel strand loading system is used to provide an adjustable hoop force, and the actuator loading system is used to provide an adjustable radial force.

2. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 1 is characterized in that: A plurality of hoop steel strand loading systems are evenly arranged on the side of each trapezoidal beam, and the hoop steel strand loading system includes a steel strand, a jack and a force sensor I; the tensioning end of the steel strand is fixed on one side of the trapezoidal beam, the tensioning end of the steel strand passes through the trapezoidal beam to fit the entire ring of pipe segments in a circumferential circle, and passes through the same trapezoidal beam again to be fixed on the other side of the same trapezoidal beam, and the end of the steel strand fixed on the other side of the same trapezoidal beam is the fixed end of the steel strand; the force sensor I and the jack are installed on the tensioning end of the steel strand, and the force sensor I is installed on the fixed end of the steel strand.

3. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 2 is characterized in that: The actuator loading system includes an actuator, a force sensor II and an annular fixing frame. The annular fixing frame is coaxially mounted outside the entire ring of segments. Multiple actuators are evenly distributed on each trapezoidal beam. Each actuator is placed radially along the entire ring of segments. A force sensor II is installed at one end of the actuator to abut against the top surface of the trapezoidal beam, and the other end of the actuator is fixed to the annular fixing frame.

4. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 3 is characterized in that: The support frame includes an inner ring steel, a square frame and an outer steel. The square frame is mounted outside the annular fixing frame and together forms a centrally symmetrical figure. A plurality of inner ring steels are evenly arranged in the annular direction of the annular fixing frame. The inner ring steels are radially arranged along the radial direction of the entire ring of pipe segments. One end of the inner ring steel is fixed to the annular fixing frame, and the other end of the inner ring steel is fixed to the square frame. The outer steel is fixed to both sides of the square frame to support the square frame.

5. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 3 is characterized in that: The actuator loading system also includes an annular base plate, which is fixed on one side of the annular fixing frame along the axial direction of the entire ring of segments. The end faces of the entire ring of segments abut against the annular base plate, and the support beam abuts against the annular base plate. The abutting surface of the support beam is provided with a directional pulley for the support beam to move radially along the entire ring of segments.

6. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in any one of claims 1 to 5, characterized in that: A rib plate is provided at the connection between the support beam and the trapezoidal beam, and the angle between the side surface of the trapezoidal beam and the radial direction of the pipe segment is 5° to 25°.

7. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 6 is characterized in that: Elliptical holes are provided on both sides of the trapezoidal beam for the steel strands on the same trapezoidal beam to pass through.

8. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 7 is characterized in that: Inclined pads are arranged in the gaps between the steel strands and the entire ring of segments on both sides of the trapezoidal beam.

9. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 7, characterized in that: The steel strands are unbonded prestressed steel strands, which are used to control the load difference between the fixed end and the tensioned end of the steel strands within 5%.

10. The full-ring shield segment loading system applicable to different water depth load conditions as claimed in claim 7, characterized in that: Rubber pads are arranged in the gaps between the bottom surface of the trapezoidal beam and the plurality of steel strands between the entire ring of segments.

Images