Pseudo-dynamic test device and method for assembling underground station structural beam-slab-column joints

Abstract

The invention discloses a pseudo-dynamic test device and method for assembling underground station structural beam-slab-column joints, and belongs to the technical field of seismic resistance of assembled underground structures, the pseudo-dynamic test device comprises a test piece model, a reaction wall, a transverse actuating mechanism, a hinged support, a clamping support and a longitudinal actuating mechanism, and the test piece model is composed of a plurality of prefabricated parts; the reaction wall comprises a reaction wall vertical wall which is vertically arranged and a reaction wall base which is horizontally arranged; the transverse actuating mechanism is fixedly arranged on the inner side of the vertical wall of the reaction wall, is connected with the top end of the prefabricated upper column and is used for transmitting a reciprocating load to simulate a transverse earthquake effect; the hinged support is fixedly connected to the reaction wall base; the clamping bracket is fixedly connected with the test piece model and is used for simulating soil pressure applied to the test piece model by two sides of a station structure; and the longitudinal actuating mechanism is fixedly connected to the reaction frame, acts on the top end of the prefabricated upper column and applies axial pressure to simulate top soil pressure and pavement load. According to the invention, the earthquake damage process and form of the large underground structure node can be visually simulated.

Description

Technical Field

[0001] The present invention relates to the technical field of aseismic technology for prefabricated underground structures, and particularly to a pseudo-dynamic test device and method for beam-slab-column joints of an assembled underground station structure, which are used to simulate the dynamic response and failure mode of joints under seismic action. Background Technique

[0002] Prefabricated buildings have the characteristics of high efficiency, environmental protection, convenience, etc. The construction method of joint assembly can greatly shorten the on-site construction period, and the modular design can effectively improve the reuse rate of formwork, with high economic benefits. Prefabricated underground structures are gradually popularized due to their characteristics of high efficiency and environmental protection; a large number of prefabricated joint tests show that the prefabricated structure can achieve seismic performance basically equivalent to that of the cast-in-place structure through reasonable joint assembly design. However, the existing prefabricated joint test methods mainly focus on above-ground structures and do not consider the mechanical characteristics of underground structures (such as earth pressure, truncated constraints, etc.).

[0003] The existing mechanical tests of underground structures are usually model tests of the overall structure, including two model test methods: the shaking table under normal gravity state and the centrifuge shaking table test under supergravity. There are the following two problems in the actual operation of the above two model test methods: both require complex model test designs of the interaction system between soil and underground structures, and there are limitations such as the inability to unify the similarity ratio, difficult preparation of the model foundation, and small size of the model structure, and it is impossible to intuitively and truly reproduce the node damage evolution processes such as the underground structure failure process and collapse form. Summary of the Invention

[0004] Technical Problem to be Solved: Aiming at the problems in the background technique that the existing joint test methods mainly focus on above-ground structures and do not consider the mechanical characteristics of underground structures (such as earth pressure, truncated constraints, etc.), and the traditional shaking table test has problems such as non-uniform similarity ratio and complex model preparation, the present invention provides a pseudo-dynamic test device and method for beam-slab-column joints of an assembled underground station structure, which can intuitively simulate the seismic failure process and its form of large underground structure joints.

[0005] Technical Solution: A pseudo-dynamic test device for beam-slab-column joints of an assembled underground station structure according to the present invention includes: A specimen model, which is composed of a plurality of prefabricated components, including a precast floor slab, a precast lower column, a precast longitudinal beam, and a precast upper column; A reaction wall, which includes a vertically arranged reaction wall vertical wall and a reaction wall base horizontally arranged at the bottom of the reaction wall vertical wall, and the reaction wall vertical wall and the reaction wall base are integrally formed; A horizontal actuator mechanism, which is horizontally and fixedly arranged along the axial direction on the inner side of the reaction wall vertical wall and is connected to the top end of the precast upper column, and is used to transmit reciprocating loads to simulate horizontal seismic action; Hinge support, which is fixedly connected to the reaction wall base; Clamping bracket, which is fixedly connected to the specimen model and is used to simulate the earth pressure exerted on the specimen model on both sides of the station structure; Longitudinal actuating mechanism, which is fixedly connected to the reaction frame on the reaction wall base, and the lower end of the longitudinal actuating mechanism acts on the top of the precast upper column and applies axial compression to simulate the top earth pressure and pavement load.

[0006] Preferably, the lateral actuating mechanism includes a lateral actuating mechanism base axially and horizontally fixed on the inner side of the vertical wall of the reaction wall. A lateral servo actuator is hinged on the lateral actuating mechanism base, and a ring clamp is connected to the power output end of the lateral servo actuator. The ring clamp is correspondingly sleeved on the top of the precast upper column.

[0007] Preferably, the longitudinal actuating mechanism includes a longitudinal actuating mechanism base fixedly connected to the reaction frame. A longitudinal servo actuator is arranged at the lower end of the longitudinal actuating mechanism base, and the power output end of the longitudinal servo actuator is connected to the top of the precast upper column.

[0008] Preferably, the top of the precast lower column is reserved with extended longitudinal bars, and the extended length of the longitudinal bars is not less than 0.9 m; a grouting sleeve is built-in at the bottom of the precast upper column, and the grouting sleeve is used for alignment connection with the extended longitudinal bars of the precast lower column.

[0009] Preferably, a circular cavity separated by a steel corrugated pipe is provided in the center of the precast longitudinal beam, and the circular cavity is used for the extended longitudinal bars of the precast lower column to pass through.

[0010] Preferably, a plurality of U-shaped lapping bars are arranged along the beam body at the top of the precast longitudinal beam. Connecting bars are arranged on the corresponding side of the precast floor slab and the precast longitudinal beam and are connected to the precast longitudinal beam through the U-shaped lapping bars. An upper-opening cavity is formed after the precast longitudinal beam and the precast floor slab are spliced for cast-in-place concrete.

[0011] Preferably, the clamping bracket includes two I-beams and two holding poles respectively installed at both ends and both sides of the precast floor slab; sliding supports fixedly connected to the reaction wall base are correspondingly arranged at the lower ends of the I-beams, and the sliding supports are used to limit the spatial height position of the precast floor slab.

[0012] The present invention also discloses a pseudo-dynamic test method for assembling beam-slab-column joints of an underground station structure, adopting the above-mentioned pseudo-dynamic test device, including the following loading steps: Step 1: Install the hinge support and the sliding support on the reaction wall base correspondingly, hoist and place the specimen model and fix it to the hinge support; Step 2: Install and fix the lateral actuating mechanism, the longitudinal actuating mechanism, and the clamping bracket to the specimen model respectively; Step 3: Apply reciprocating loads through the transverse actuation mechanism to simulate earthquake effects, adjust the axial pressure and the preload force of the holding rod through the longitudinal actuation mechanism, record the test data, and analyze the node failure process.

[0013] Compared with the prior art, the present invention has at least the following outstanding advantages: 1. The pseudo-dynamic test equipment and method of the present invention simulates earth pressure transmitted laterally from the station structure by fixedly connecting a clamping bracket to a specimen model. Axial compression is applied to the top of the precast upper column to simulate earth pressure and road surface load transmitted from the upper portion of the station structure. Reciprocating loads are applied to the sides of the top of the precast upper column to simulate the seismic response of the node under lateral earthquake action. By simulating actual constraints, the test conforms to the stress characteristics of underground structures and improves the accuracy of test data. Furthermore, the graded loading system can be compared with the seismic performance level classification of underground station structures based on interstory drift angle (IDR). 2. The pseudo-dynamic test equipment and method of the present invention can avoid the defect of unifying the similarity ratio of the soil-structure dynamic interaction system. Compared with the whole model test, the interception of key nodes is less affected by the size effect, making it easier to observe the evolution process of structural damage. 3. Adopt a graded loading system directly linked to the seismic performance level to guide engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural front view of the pseudo-power experimental device of the present invention; Figure 2 for Figure 1 A top view of the structure of the medium-sized pseudo-dynamic experimental device; Figure 3 is a loading system diagram of the method of the present invention; Figure 4 for Figure 1 Main view of the test specimen model structure; Figure 5 for Figure 4 Schematic diagram of precast floor structure; Figure 6 for Figure 4 Schematic diagram of the prefabricated lower column structure; Figure 7 for Figure 4 Schematic diagram of the prefabricated longitudinal beam structure; Figure 8 for Figure 4 Schematic diagram of the prefabricated upper column structure; Figure 9 for Figure 4 Flowchart of test specimen model assembly.

[0015] Figure numerals: 1. vertical wall of reaction wall; 2. base of reaction wall; 3. positioning slot; 4. transverse actuating mechanism; 41. base of transverse actuating mechanism; 42. transverse servo actuator; 5. first connecting bolt; 6. fixing bolt of hinge support; 7. hinge support; 8. specimen model; 81. prefabricated floor slab; 811. connecting steel bar; 82. prefabricated lower column; 821. longitudinal reinforcement; 83. prefabricated longitudinal beam; 831. circular cavity; 832. U-shaped lap reinforcement; 84. prefabricated upper column; 841. grouting sleeve; 9. I-beam; 10. holding rod; 11. sliding support; 12. longitudinal actuating mechanism; 121. base of longitudinal actuating mechanism; 122. longitudinal servo actuator; 13. ring clamp; 14. reaction frame. DETAILED DESCRIPTION

[0016] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following Figures 1 to 9 The technical solutions of the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0017] Example 1: Figures 1 to 2 As shown, the present invention discloses a pseudo-dynamic test device for assembling beam-slab-column nodes of underground station structures. The pseudo-dynamic test device includes a specimen model 8, a reaction wall, a transverse actuating mechanism 4, a hinge support 7, a clamping bracket and a longitudinal actuating mechanism 12.

[0018] like Figures 4 to 9 As shown, the specimen model 8 is composed of multiple prefabricated components, including a prefabricated floor 81, a prefabricated lower column 82, a prefabricated longitudinal beam 83 and a prefabricated upper column 84; an outward-extending longitudinal reinforcement 821 is reserved at the top of the prefabricated lower column 82, and the outward-extending length of the longitudinal reinforcement 821 is not less than 0.9 m; a grouting sleeve 841 is built into the bottom of the prefabricated upper column 84, and the grouting sleeve 841 is used to align and connect with the outward-extending longitudinal reinforcement 821 of the prefabricated lower column 82; a circular cavity 831 isolated by a steel corrugated pipe is provided in the center of the prefabricated longitudinal beam 83, and the circular cavity 831 is used for the outward-extending longitudinal reinforcement 821 of the prefabricated lower column 82 to pass through. A plurality of U-shaped lap reinforcements 832 are provided at the top of the precast longitudinal beam 83 along the direction of the beam body. The precast floor slab 81 includes two corresponding pieces arranged along the two sides of the precast longitudinal beam 83. The precast floor slab 81 and the precast longitudinal beam 83 are provided with connecting steel bars 811 on the corresponding side and are connected to the precast longitudinal beam 83 through U-shaped lap reinforcements 832. After the precast longitudinal beam 83 and the precast floor slab 81 are spliced, an upper open cavity is formed for post-pouring concrete.

[0019] like Figure 1As shown in the figure, the reaction wall includes a vertically arranged reaction wall vertical wall 1 and a reaction wall base 2 horizontally arranged at the bottom of the reaction wall vertical wall 1. The reaction wall vertical wall 1 and the reaction wall base 2 are integrally formed. A set of positioning slot holes 3 are evenly opened on the reaction wall vertical wall 1, and the lateral actuator mechanism 4 is fixedly connected to the positioning slot holes 3 of the reaction wall vertical wall 1 through the first connecting bolts 5.

[0020] As Figures 1 to 2 shown in the figure, the lateral actuator mechanism 4 includes a lateral actuator mechanism base 41 horizontally and axially fixed on the inner side of the reaction wall vertical wall 1. A lateral servo actuator 42 is hinged on the lateral actuator mechanism base 41. The power output end of the lateral servo actuator 42 is connected with an annular clamp 13, and the annular clamp 13 is correspondingly sleeved on the top end of the precast upper column 84. The lateral actuator mechanism 4 is used to transfer the reciprocating load to simulate the lateral seismic action.

[0021] As Figure 1 shown in the figure, the hinge support 7 is fixedly connected to the reaction wall base 2 through the hinge support fixing bolts 6, and the precast lower column 82 of the specimen model 8 for assembling the beam-slab-column joint of the underground station structure is correspondingly installed on the hinge support 7.

[0022] As Figures 1 to 2 shown in the figure, the clamping bracket includes two I-beams 9 and two holding rods 10 respectively installed at both ends and both sides of the precast floor slab 81. The lower ends of the I-beams 9 are correspondingly provided with sliding supports 11 fixedly connected to the reaction wall base 2, and the sliding supports 11 are used to limit the spatial height position of the precast floor slab 81. The clamping bracket is fixedly connected to the specimen model 8 and is used to simulate the soil pressure applied to the specimen model 8 on both sides of the station structure.

[0023] As Figure 1 shown in the figure, a reaction frame 14 is fixedly connected to the reaction wall base 2. The longitudinal actuator mechanism 12 includes a longitudinal actuator mechanism base 121 fixedly connected to the reaction frame 14. The lower end of the longitudinal actuator mechanism base 121 is provided with a longitudinal servo actuator 122, and the power output end of the longitudinal servo actuator 122 is connected to the top end of the precast upper column 84. The lower end of the longitudinal actuator mechanism 12 acts on the top end of the precast upper column 84 and applies axial compression to simulate the top soil pressure and the road surface load.

[0024] The pseudo-dynamic test equipment of the present invention is fixedly connected to the specimen model 8 through the clamping bracket to simulate the soil pressure transmitted laterally from the station structure, applies axial compression to the top of the precast upper column 84 to simulate the soil pressure and the road surface load transmitted from the upper part of the station structure, applies reciprocating load to the side of the top of the precast upper column 84 to simulate the seismic response of the joint under the lateral seismic action, and conforms to the stress characteristics of the underground structure by simulating the actual constraint conditions, thereby improving the accuracy of the test data.

[0025] Embodiment 2: The present invention also discloses a pseudo-dynamic test method for assembling beam-slab-column joints of an underground station structure. Using the above-mentioned pseudo-dynamic test device, it includes the following loading steps: (I) Installation of the specimen model 8: The hinge support 7 and the sliding support 11 are correspondingly installed on the reaction wall base 2. The specimen model 8 is hoisted and fixed to the hinge support 7 and the sliding support 11. According to the installation position of the specimen model 8, the lateral actuator 4, the longitudinal actuator 12, and the clamping bracket are respectively installed and fixed to the specimen model 8. Specifically, the lower end of the precast lower column 82 of the specimen model 8 is correspondingly supported on the hinge support 7. The two I-beams 9 and the two holding poles 10 of the clamping bracket are correspondingly connected to the four sides of the precast floor slab 81 and the precast longitudinal beam 83 and fixed, and then the two I-beams 9 are fixedly connected to the corresponding sliding supports 11.

[0026] (II) Pseudo-dynamic test and earthquake simulation operation of the specimen model 8: The lateral actuator 4 and the longitudinal actuator 12 are connected to an external power supply, and the power is adjusted according to the earthquake intensity to be simulated. The reciprocating load applied by the lateral actuator 4 is used to simulate the vibration of the specimen model 8, and the axial pressure of the longitudinal actuator 12 and the pre-tightening force of the holding pole 10 can be adjusted as needed to simulate different pre-earthquake stress states of the specimen model 8. The data of the simulation test are recorded and compared, and the earthquake damage process and collapse form of the specimen model 8 can be visually observed.

[0027] In Embodiment 2 of the present invention, a hierarchical loading system is used and compared with the seismic performance level classification of the underground station structure based on the inter-story drift ratio (IDR) (as shown in Table 1); the lateral actuator 4 adopts a dynamic loading system (such as Figure 3 and Table 2).

[0028] Table 1 IDR comparison table: .

[0029] Table 2 Dynamic loading system of the lateral actuator 4: .

[0030] The method of the present invention uses a hierarchical loading system and is compared with the seismic performance level classification of the underground station structure based on the inter-story drift ratio IDR, avoiding the defect that the similarity ratio of the soil-structure dynamic interaction system cannot be unified, and the influence of the size effect on the key nodes intercepted is smaller than that of the overall model test, making it easier to observe the structural damage evolution.

[0031] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A pseudo-dynamic test device for assembling beam-slab-column joints of an underground station structure, characterized in that Comprising: A specimen model (8), which is composed of multiple precast components, including a precast floor slab (81), a precast lower column (82), a precast longitudinal beam (83) and a precast upper column (84); A reaction wall, which includes a vertically arranged reaction wall vertical wall (1) and a reaction wall base (2) horizontally arranged at the bottom of the reaction wall vertical wall (1), and the reaction wall vertical wall (1) and the reaction wall base (2) are integrally formed; A lateral actuator (4), which is horizontally fixed along the axial direction on the inner side of the reaction wall vertical wall (1) and is connected to the top end of the precast upper column (84) for transmitting reciprocating loads to simulate lateral seismic action; A hinge support (7), which is fixedly connected to the reaction wall base (2); A clamping bracket, which is fixedly connected to the specimen model (8) for simulating the earth pressure applied to the specimen model (8) on both sides of the station structure; A longitudinal actuator (12), which is fixedly connected to a reaction frame (14) on the reaction wall base (2), and the lower end of the longitudinal actuator (12) acts on the top end of the precast upper column (84) to apply axial compression to simulate the top earth pressure and road surface load.

2. The pseudo-dynamic test device for assembling the beam-slab-column joints of the underground station structure according to claim 1, characterized in that, The lateral actuator (4) includes a lateral actuator base (41) horizontally fixed along the axial direction on the inner side of the reaction wall vertical wall (1), a lateral servo actuator (42) is hinged on the lateral actuator base (41), and the power output end of the lateral servo actuator (42) is connected with an annular clamp (13), and the annular clamp (13) is correspondingly sleeved on the top end of the precast upper column (84).

3. The pseudo-dynamic test device for assembling beam-slab-column joints of an underground station structure according to claim 1, characterized in that, The longitudinal actuator (12) includes a longitudinal actuator base (121) fixedly connected to the reaction frame (14), a longitudinal servo actuator (122) is arranged at the lower end of the longitudinal actuator base (121), and the power output end of the longitudinal servo actuator (122) is connected with the top end of the precast upper column (84).

4. The pseudo-dynamic test device for assembling the beam-slab-column joints of the underground station structure according to claim 1, characterized in that, The top of the precast lower column (82) is reserved with extended longitudinal reinforcement (821), and the extended length of the longitudinal reinforcement (821) is not less than 0.9 m; a grouting sleeve (841) is built in the bottom of the precast upper column (84), and the grouting sleeve (841) is used for butt joint connection with the extended longitudinal reinforcement (821) of the precast lower column (82).

5. The pseudo-dynamic test device for assembling the beam-slab-column joints of the underground station structure according to claim 4, characterized in that, A circular cavity (831) separated by a steel corrugated pipe is provided in the center of the precast longitudinal beam (83), and the circular cavity (831) is used for the extended longitudinal reinforcement (821) of the precast lower column (82) to pass through.

6. The pseudo-dynamic test device for assembling the beam-slab-column joints of the underground station structure according to claim 5, characterized in that, A plurality of U-shaped lapping bars (832) are arranged along the beam body direction at the top end of the precast longitudinal beam (83), connecting steel bars (811) are arranged on the corresponding side of the precast floor slab (81) and the precast longitudinal beam (83) and are connected with the precast longitudinal beam (83) through the U-shaped lapping bars (832), and an upper opening cavity is formed after the precast longitudinal beam (83) and the precast floor slab (81) are spliced for post-cast concrete.

7. The pseudo-dynamic test device for assembling beam-slab-column joints of an underground station structure according to claim 1, characterized in that, The clamping bracket includes two I-beams (9) and two holding poles (10) respectively installed at both ends and both sides of the precast floor slab (81); a sliding support (11) fixedly connected to the reaction wall base (2) is correspondingly arranged at the lower end of the I-beam (9), and the sliding support (11) is used to limit the spatial height position of the precast floor slab (81).

8. A pseudo-dynamic test method for assembling beam-slab-column joints of an underground station structure, characterized in that, Adopt the pseudo-dynamic test device according to any one of claims 1 to 7, including the following loading steps: Step 1: Install the hinge support (7) and the sliding support (11) on the reaction wall base (2) correspondingly, lift and place the specimen model (8) and fix it to the hinge support (7); Step 2: Install and fix the lateral actuator mechanism (4), the longitudinal actuator mechanism (12), and the clamping bracket to the specimen model (8) respectively; Step 3: Apply a reciprocating load through the lateral actuator mechanism (4) to simulate the earthquake action, adjust the axial pressure and the pre-tightening force of the holding pole (10) through the longitudinal actuator mechanism (12), record the test data and analyze the node failure process.

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