Vibration reduction pile head for high-frequency horizontal vibration load

Abstract

The utility model discloses a vibration reduction pile head for a high-frequency horizontal vibration load. The vibration reduction pile head comprises a precast pile body and an annular base. The upper end of the annular base is tightly attached to the lower face of the cast-in-place bearing platform, the height of the annular base is the horizontal vibration load influence depth H, and the wall thickness B needs to meet the lateral stiffness that horizontal displacement does not exceed 1 mm under the maximum impact load effect of a train. A plurality of intelligent shock absorbers evenly distributed around the axis are arranged between the inner side wall of the annular base and the outer side wall of the precast pile body. Each intelligent shock absorber comprises a telescopic shell, a damper, an elastic element and a frequency detector, wherein the damper, the elastic element and the frequency detector are connected with an external control system in a wireless mode. The external control system adjusts the damping R of the damper and the spring stiffness k of the elastic element according to the frequency of the horizontal vibration load collected by the frequency detector. The prefabricated pile solves the problem that the prefabricated pile is insufficient in high-frequency horizontal vibration bearing capacity under the long-term operation condition of 140-160km / h rail transit.

Description

Technical Field

[0001] The utility model relates to the technical field of elevated rail transit construction, in particular to a vibration-damping pile head for high-frequency horizontal vibration loads. Background Art

[0002] In the existing rail transit technology, urban rail sections usually adopt an elevated structure, with piers and pile foundations arranged under the elevated structure. The vertical load is transferred to the lower pedestal and pile foundation through the piers.

[0003] Compared with traditional rail transit, urban rail trains run faster, with speeds of up to 140km / h to 160km / h. Under the long-term repeated action of high-speed train loads, the lower pedestal and pile head will be subjected to greater high-frequency horizontal vibration loads. Over time, the pedestal and pile head parts that directly bear the impact of the load are prone to loosening and large horizontal deformation, which brings huge safety hazards to the long-term operation of urban rail.

[0004] Existing precast piles have the characteristics of high bearing capacity and small pile cross-section. Therefore, compared with traditional bored cast-in-place piles, precast piles have smaller horizontal stiffness and are more likely to undergo large horizontal deformation under high-frequency horizontal vibration loads.

[0005] Therefore, how to solve the problem of insufficient ability of precast piles to bear high-frequency horizontal vibrations under long-term operation conditions of 140km / h to 160km / h rail transit and eliminate safety hazards in rail transit operation has become a technical problem that technical personnel in this field urgently need to solve. Utility Model Content

[0006] In view of the above-mentioned defects of the prior art, the utility model provides a vibration-damping pile head for high-frequency horizontal vibration loads, which aims to solve the problem of insufficient capacity of precast piles to bear high-frequency horizontal vibration under the long-term operation conditions of 140km / h to 160km / h rail transit, and eliminate safety hazards in rail transit operation.

[0007] To achieve the above-mentioned purpose, the utility model discloses a vibration-damping pile head for high-frequency horizontal vibration loads, comprising a prefabricated pile body;

[0008] The top of the precast pile body is fixedly connected to the cast-in-place cap, and a coaxially arranged annular base is sleeved on the outer side near the top;

[0009] The upper end of the annular base is in close contact with the bottom of the cast-in-place cap, and the height is the horizontal vibration load influence depth H. The wall thickness B needs to meet the lateral stiffness of not exceeding 1mm horizontal displacement under the maximum impact load of the train;

[0010] A plurality of intelligent shock absorbers evenly distributed around the axis are provided between the inner side wall of the annular base and the outer side wall of the precast pile body;

[0011] Each of the intelligent shock absorbers comprises a retractable housing, and a damper, an elastic element and a frequency detector arranged in the housing;

[0012] Each of the dampers is used to generate a damping effect when the corresponding retractable housing is retracted or extended;

[0013] Each of the elastic elements is used to generate a restoring force to restore the corresponding retractable housing to its original state after the retractable housing is retracted;

[0014] Each of the frequency detectors is used to collect the frequency of the horizontal vibration load to which the corresponding retractable housing is subjected;

[0015] The damper, the elastic element and the frequency detector of each intelligent shock absorber are connected to an external control system in a wireless manner;

[0016] The external control system adjusts the damping R of the corresponding damper and the spring stiffness k of the corresponding elastic element according to the frequency of the horizontal vibration load collected by the frequency detector of each intelligent shock absorber.

[0017] Preferably, the precast pile body is a steel structure or a concrete structure.

[0018] Preferably, a circle of annular embedded steel plate is provided at the top of the precast pile body near the side wall, and the precast pile body is fixedly connected to the cast-in-place foundation by pouring the part of the precast pile body near the top, the embedded steel plate arranged at the top, and the connecting steel bars arranged on the embedded steel plate onto the cast-in-place foundation.

[0019] Preferably, the annular base is cast in situ or prefabricated using a material having a density of not less than 7.85 g / cm3 and a compressive elastic modulus of not less than 3.35E4 Mpa.

[0020] Preferably, both ends of the retractable shell of each of the intelligent shock absorbers are respectively connected to the outer wall of the prefabricated pile body and the inner wall of the annular base;

[0021] Each of the retractable shells is connected to the outer wall of the precast pile body or the inner wall of the annular base through a pre-embedded connector pre-embedded in the outer wall of the precast pile body or the inner wall of the annular base.

[0022] Beneficial effects of the utility model:

[0023] The utility model provides a pile head expansion ring and a horizontal intelligent shock absorber to control the deformation of the pile head under the horizontal vibration load in real time according to the size of the train impact load transmitted from the upper part, thereby reducing the risk of connection failure. The method is simple, safe and reliable, which promotes the technological progress of the industry and has good economic and social benefits.

[0024] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the longitudinal cross-section structure of an embodiment of the utility model is shown.

[0026] Figure 2 A schematic diagram of the cross-sectional structure of the annular base portion in one embodiment of the utility model is shown.

[0027] Figure 3 A schematic structural diagram of an intelligent shock absorber in one embodiment of the utility model is shown.

[0028] Figure 4 A flow chart of the damping process of the intelligent shock absorber in one embodiment of the utility model is shown. DETAILED DESCRIPTION

[0029] Example

[0030] like Figures 1 to 3 As shown, a vibration-damping pile head for high-frequency horizontal vibration loads comprises a prefabricated pile body 1;

[0031] The top of the precast pile body 1 is fixedly connected to the cast-in-place cap 7, and a coaxially arranged annular base 2 is sleeved on the outer side near the top;

[0032] The upper end of the annular base 2 is in close contact with the bottom of the cast-in-place cap 7, and the height is the horizontal vibration load impact depth H. The wall thickness B needs to meet the lateral stiffness of not exceeding 1mm horizontal displacement under the maximum impact load of the train;

[0033] A plurality of intelligent vibration dampers 3 evenly distributed around the axis are provided between the inner side wall of the annular base 2 and the outer side wall of the precast pile body 1;

[0034] Each intelligent shock absorber 3 includes a retractable housing, and a damper 4, an elastic element 5 and a frequency detector 6 arranged in the housing;

[0035] Each damper 4 is used to generate a damping effect when the corresponding retractable housing is extended or retracted;

[0036] Each elastic element 5 is used to generate a restoring force to restore the corresponding retractable housing to its original state after the retractable housing is retracted.

[0037] Each frequency detector 6 is used to collect the frequency of the horizontal vibration load to which the corresponding retractable housing is subjected;

[0038] The damper 4, elastic element 5 and frequency detector 6 of each intelligent shock absorber 3 are connected to the external control system in a wireless manner;

[0039] The external control system adjusts the damping R of the corresponding damper 4 and the spring stiffness k of the corresponding elastic element 5 according to the frequency of the horizontal vibration load collected by the frequency detector 6 of each intelligent shock absorber 3 .

[0040] The utility model sets an annular base 2 and a plurality of intelligent shock absorbers 3 within the range of a depth H of influence of a horizontal vibration load near a cast-in-place cap 7 on a precast pile body 1. The intelligent shock absorbers 3 adjust the deformation of the precast pile body 1 under a horizontal vibration load in real time according to the magnitude of the train impact load transmitted from the upper part, thereby reducing the risk of connection failure. The method is simple, safe and reliable, promotes technological progress in the industry, and has good economic and social benefits.

[0041] In practical applications, since the impact load from outside the horizontal vibration load influence depth H on the precast pile body 1 can be ignored, the distance between the connector and the bottom of the cast-in-place cap 7 is the horizontal vibration load influence depth H, which can most effectively achieve shock absorption of the impact load.

[0042] The magnitude of the depth H affected by the horizontal vibration load needs to be determined comprehensively based on the maximum impact load of the train, the horizontal stiffness of the pedestal and precast piles, and numerical simulation.

[0043] All intelligent shock absorbers 3 adjust the damping R of the damper 4 and the spring stiffness k of the corresponding elastic element 5 according to the external horizontal vibration load of different frequencies, so as to achieve the desired change of natural frequency, avoid the resonance area, and thus achieve the adjustment of vibration reduction efficiency.

[0044] In some embodiments, the precast pile body 1 is a steel structure or a concrete structure.

[0045] In actual applications, the length, diameter, wall thickness, etc. of the prefabricated pile body 1 are all conventional in the art, and basic information such as length, diameter, wall thickness, etc. are included in the design drawings for easy processing.

[0046] In some embodiments, a circle of annular embedded steel plate 11 is provided at the top of the precast pile body 1 near the side wall, and the part of the precast pile body 1 near the top, the embedded steel plate 11 arranged at the top, and the connecting steel bars 12 arranged on the embedded steel plate 11 are cast on the cast-in-place foundation 7 to achieve a fixed connection with the cast-in-place foundation 7.

[0047] In some embodiments, the annular base 2 is cast in situ or prefabricated using a material having a density of not less than 7.85 g / cm3 and a compressive elastic modulus of not less than 3.35E4 Mpa.

[0048] In some embodiments, both ends of the retractable shell of each intelligent shock absorber 3 are respectively connected to the outer wall of the precast pile body 1 and the inner wall of the annular base 2;

[0049] Each retractable shell is connected to the outer wall of the precast pile body 1 or the inner wall of the annular base 2 through a pre-embedded connector pre-embedded in the outer wall of the precast pile body 1 or the inner wall of the annular base 2 respectively.

[0050] In practical applications, each retractable shell is connected to the outer wall of the precast pile body 1 or the inner wall of the annular base 2 through a pre-embedded connector pre-embedded in the outer wall of the precast pile body 1 or the inner wall of the annular base 2, respectively, to ensure the rapid connection of each intelligent shock absorber 3 in the later stage. The type and position of the pre-embedded connector can be adjusted according to actual conditions.

[0051] The utility model also provides a construction method for a vibration-damping pile head for high-frequency horizontal vibration loads, the steps of which are as follows:

[0052] Step A1, transporting the precast pile body 1 to the site, and using a pile driver to press the precast pile body 1 to the designed elevation;

[0053] Step A2, excavating earth within the range of the horizontal vibration load influence depth H around the precast pile body 1, burying the annular base 2, and installing all intelligent shock absorbers 3 between the precast pile body 1 and the annular base 2;

[0054] Step A3, the gap between the precast pile body 1 and the annular base 2 is filled and compacted by grouting;

[0055] Step A4: Cast the cast-in-place cap 7 and fix it to the top of the precast pile body 1.

[0056] like Figure 4 As shown, the utility model also provides a vibration reduction method for a vibration reduction pile head for high-frequency horizontal vibration loads, characterized in that the steps are as follows:

[0057] Step B1, when a train passes by and generates horizontal vibration load to induce high-frequency horizontal vibration, the frequency detector 6 of each intelligent shock absorber 3 feeds back the real-time detected vibration frequency f to the external control system;

[0058] Step B2: The external control system compares each vibration frequency f with the preset alarm value f max For comparison; when any vibration frequency f is higher than the alarm value f maxWhen the damper 4 and the elastic element 5 of the corresponding intelligent shock absorber 3 are adjusted, a command is issued to adjust the damping R of the corresponding damper 4 and the spring stiffness k of the corresponding elastic element 5;

[0059] As the damping R of the corresponding damper 4 changes and the spring stiffness k of the corresponding elastic element 5 is adjusted, the frequency detector 6 of the corresponding intelligent shock absorber 3 will rapidly attenuate the vibration frequency f detected in real time;

[0060] Step B3: When the vibration frequency f decays to the alarm value f max When the following is performed, a command is issued to the damper 4 and the elastic element 5 of the corresponding intelligent shock absorber 3 to adjust the damping R of the corresponding damper 4 and the spring stiffness k of the corresponding elastic element 5 to the initial value.

[0061] Through the above-mentioned intelligent vibration reduction process, the utility model enables the corresponding intelligent vibration absorber 3 to always be in the best vibration reduction state under the current external vibration excitation, ensuring that the foundation and pile head do not undergo large vibration deformation during the whole process, thereby ensuring safety during the entire urban rail operation process.

[0062] The preferred specific embodiments of the utility model are described in detail above. It should be understood that ordinary technicians in this field can make many modifications and changes based on the concept of the utility model without creative work. Therefore, all technical solutions that can be obtained by technicians in this technical field based on the concept of the utility model through logical analysis, reasoning or limited experiments on the basis of the existing technology should be within the scope of protection determined by the claims.

Claims

1. A vibration-damping pile head for high-frequency horizontal vibration loads; characterized in that: It comprises a prefabricated pile body (1); The top of the precast pile body (1) is fixedly connected to the cast-in-place cap (7), and a coaxially arranged annular base (2) is sleeved on the outer side near the top; The upper end of the annular base (2) is in close contact with the lower side of the cast-in-place pedestal (7), and the height is the horizontal vibration load impact depth H. The wall thickness B needs to satisfy the lateral stiffness that does not cause a horizontal displacement exceeding 1 mm under the maximum impact load of the train; A plurality of intelligent vibration dampers (3) evenly distributed around the axis are provided between the inner side wall of the annular base (2) and the outer side wall of the precast pile body (1); Each of the intelligent vibration absorbers (3) comprises a retractable housing, and a damper (4), an elastic element (5) and a frequency detector (6) arranged in the housing; Each of the dampers (4) is used to generate a damping effect when the corresponding retractable housing is retracted or extended; Each of the elastic elements (5) is used to generate a restoring force to restore the corresponding retractable housing to its original state after the retractable housing is retracted. Each of the frequency detectors (6) is used to collect the frequency of the horizontal vibration load to which the corresponding retractable housing is subjected; The damper (4), the elastic element (5) and the frequency detector (6) of each of the intelligent shock absorbers (3) are connected to an external control system in a wireless manner; The external control system adjusts the damping R of the corresponding damper (4) and the spring stiffness k of the corresponding elastic element (5) according to the frequency of the horizontal vibration load collected by the frequency detector (6) of each of the intelligent shock absorbers (3).

2. The vibration-damping pile head for high-frequency horizontal vibration loads according to claim 1, characterized in that: The prefabricated pile body (1) is a steel structure or a concrete structure.

3. The vibration-damping pile head for high-frequency horizontal vibration loads according to claim 1, characterized in that: A ring-shaped embedded steel plate (11) is provided at the top of the precast pile body (1) near the side wall, and the precast pile body (1) is fixedly connected to the cast-in-place cap (7) by pouring the part of the precast pile body (1) near the top, the embedded steel plate (11) arranged at the top, and the connecting steel bars (12) arranged on the embedded steel plate (11) on the cast-in-place cap (7).

4. The vibration-damping pile head for high-frequency horizontal vibration loads according to claim 1, characterized in that: The annular base (2) is cast in situ or prefabricated using a material having a density of not less than 7.85 g / cm3 and a compressive elastic modulus of not less than 3.35E4 Mpa.

5. The vibration-damping pile head for high-frequency horizontal vibration loads according to claim 1, characterized in that: Both ends of the retractable outer shell of each of the intelligent shock absorbers (3) are respectively connected to the outer wall of the prefabricated pile body (1) and the inner wall of the annular base (2); Each of the retractable shells is respectively connected to the outer wall of the precast pile body (1) or the inner wall of the annular base (2) via a pre-embedded connecting piece pre-embedded in the outer wall of the precast pile body (1) or pre-embedded in the inner wall of the annular base (2).

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