CN107630477A - A kind of CYCLIC LOADING system for testing offshore foundation pile-soil interaction - Google Patents

Abstract

The invention belongs to the field of civil engineering, and in particular relates to a cyclic loading system for testing the pile-soil interaction of offshore foundations. A cyclic loading system for testing the pile-soil interaction of offshore foundations, including unidirectional horizontal cyclic loading, bidirectional horizontal cyclic loading, vertical cyclic loading, vertical and unidirectional horizontal cyclic loading, and multi-directional horizontal cyclic loading; the loading device It consists of a test box, drainage board, fixed pulley, pile foundation model, displacement sensor, strain gauge, tensile pressure sensor, weight loading rod, spring, motor, wheel disc, threaded column, bottom plate, and steel ring. The invention solves the problem that the existing test device can only carry out vertical loading or horizontal loading alone, can simulate vertical, horizontal, horizontal two-way, vertical and horizontal, and multi-directional cyclic load loading conditions, and has a test box and The drainage board can consider the influence of the change of soil moisture content and the angle between the direction of horizontal cyclic load.

Description

A Cyclic Loading System for Testing Pile-Soil Interaction of Offshore Foundations

technical field

The invention belongs to the field of civil engineering, and in particular relates to a cyclic loading system for testing the pile-soil interaction of offshore foundations.

Background technique

With the intensification of the world energy crisis and environmental pollution problems, the development and utilization of new energy sources have attracted widespread attention from all over the world. Although offshore wind power generation started late, it is easy to develop large-scale centralized development and does not occupy land resources due to its abundant storage capacity, wide distribution, and convenience for large-scale centralized development. In recent years, it has developed rapidly at home and abroad. The construction of my country's wind farms will greatly alleviate the energy crisis in the eastern region of my country, and optimizing the grid structure is an important method to achieve sustainable development and has great strategic significance.

In offshore wind power projects, the foundation forms include single pile foundation, multi-pile foundation, single cylinder foundation, multi-tube foundation, composite foundation and floating foundation. During the operation period, the superstructure has to bear the obvious periodic cyclic loads such as wind and waves. Under the joint action of the wind power tower and wind turbine equipment's self-weight load, the wind turbine's working load, and the vertical and horizontal cyclic loads generated by the wind load, the wind power foundation is prone to cumulative settlement deformation. If this deformation is not effectively controlled, it will It will seriously affect the normal operation and safe operation of the fan. Finding a reasonable method to predict and control the bearing capacity and cumulative deformation of wind power foundations under vertical and horizontal cyclic loads is of great significance to ensure the normal operation and safety of these projects.

For foundations under vertical and horizontal cyclic loads, the construction of wind power foundations faces two problems:

(1) Prediction of cumulative deformation of wind power foundation under cyclic loading;

(2) Determination of the bearing capacity of wind power foundation under cyclic load. Obviously, there is still a lack of more reliable analysis methods for the above two aspects. In order to make up for the limitations of theoretical analysis, it is necessary to analyze important projects in combination with indoor model tests. The key technology is how to simulate the foundation bearing vertical cyclic loads, horizontal cyclic loads, two-way cyclic loads and cyclic loads under different horizontal angles. effect, but no reports on this issue have been found so far.

Contents of the invention

In order to overcome the above-mentioned defects in the prior art, the present invention provides a test system for simulating cyclic load action with wide application range, simple operation of the test process, low cost, and convenient disassembly and assembly.

To achieve the above object, the present invention adopts the following scheme:

A cyclic loading system for testing the pile-soil interaction of offshore foundations includes: one-way horizontal cyclic loading, two-way horizontal cyclic loading, vertical cyclic loading, and multi-directional horizontal cyclic loading, wherein the loading device consists of a test box, a drainage board, a fixed pulley, The pile foundation model, displacement sensor, strain gauge, tensile pressure sensor, weight loading rod, spring, motor, wheel disc, threaded column, bottom plate and steel ring are assembled.

Compared with the prior art, the present invention has the following advantages:

(1) The present invention is simple to operate, and by combining loading equipment, it solves the problem that the existing test device can only carry out vertical loading or horizontal loading alone, and can also simulate vertical, horizontal, horizontal two-way, vertical and horizontal, Multi-directional cyclic load loading case.

(2) The present invention has a test box and a drainage board, and can consider the influence of the variation of the water content of the soil and the angle included in the direction of the horizontal cyclic load.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide further understanding of the present application, and the schematic embodiments and descriptions of the present application are used to explain the present application, and do not constitute improper limitations to the present application.

Fig. 1 is the structure schematic diagram of multiple loading modes of the present invention;

Fig. 2 is a plane schematic diagram of unidirectional horizontal cyclic loading;

Figure 3 is a schematic diagram of the elevation of unidirectional horizontal cyclic loading;

Figure 4 is a schematic diagram of a two-way horizontal cyclic loading plane;

Figure 5 is a schematic diagram of the elevation of two-way horizontal cyclic loading;

Fig. 6 is a schematic diagram of vertical cyclic loading elevation;

Figure 7 is a schematic diagram of vertical and unidirectional horizontal cyclic loading elevations;

Figure 8 is a schematic diagram of a multidirectional horizontal cyclic loading plane;

Fig. 9 is a schematic diagram of a plan view of the steel ring;

Figure 10 is a schematic diagram of the connection between the steel ring and the pile foundation model;

In the figure: 1. Test box, 2. Drain board, 3. Fixed pulley, 4. Pile foundation model, 5. Displacement sensor, 6. Strain gauge, 7. Tensile pressure sensor, 8. Weight loading rod, 9. Spring , 10, motor, 11, roulette, 12, threaded column, 13, bottom plate, 14, steel ring.

Detailed ways

It should be pointed out that the following detailed description is exemplary and intended to provide further explanation to the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used here is only for describing specific implementations, and is not intended to limit the exemplary implementations according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations, means, components and/or combinations thereof.

As introduced in the background technology, aiming at the deficiencies in the prior art, in order to solve the above technical problems, the present application proposes a cyclic loading system for testing the pile-soil interaction of offshore foundations.

A cyclic loading system for testing the pile-soil interaction of offshore foundations, including one-way horizontal cyclic loading, two-way horizontal cyclic loading, vertical cyclic loading, vertical and unidirectional horizontal cyclic loading, and multi-directional horizontal cyclic loading, wherein the loading device consists of Test box 1, drainage board 2, fixed pulley 3, pile foundation model 4, displacement sensor 5, strain gauge 6, tension pressure sensor 7, weight loading rod 8, spring 9, motor 10, wheel disc 11, threaded column 12, Base plate 13, steel ring 14 form.

The test box 1 is a cuboid without a cover reinforced by angle steel. The four inner walls of the test box 1 are provided with drainage boards 2. The drainage board 2 is made of water-permeable wood boards. The lower end of the inner wall of the test box 1 is provided with drainage holes. body.

The fixed pulley 3 is fixed in position by a support frame. For simplicity, the support frame in the figure is omitted, and the material of the fixed pulley 3 is a high-strength alloy.

The two ends of the spring 9 are respectively connected with a thin wire rope, one end of the thin wire rope is directly connected with the threaded post 12, the other end of the thin wire rope bypasses the fixed pulley 3, and is horizontally or vertically connected to the top of the pile foundation model 4 through the tension pressure sensor 7.

The pile foundation model 4 is partly buried in the soil used in the test. The pile foundation model 4 is located on the pile wall of the soil part, and a strain gauge 6 is pasted on the pile wall. A displacement sensor 5 is arranged on the upper surface of the soil body. In order to facilitate the connection of thin steel wire ropes, the pile The pile top of the foundation model 4 and the welded steel ring 14 located at 10 cm from the upper surface of the soil.

The motor 10 is a speed-regulating motor. The motor 10 can realize different speeds and torques under the drive of the frequency converter to adapt to the change of load requirements. The bottom plate 13 is a rectangular steel plate with a bolt installation port; the motor 10 is connected to the bottom plate 13 through bolts One side of the rotating shaft of the motor 10 is provided with a wheel disc 11, and the wheel disc 11 is provided with a threaded post 12, and the threaded post 12 and the spring 9 are connected by a thin wire rope.

The wheel disc 11 is a circular steel plate with a plurality of bolt holes, and the distance between each bolt hole and the center of the wheel disc 11 is different. The threaded post 12 is a cylindrical steel bar with threads at the end, and the threaded post 12 can be installed on the On the different bolt ports of wheel disc 11.

The steel ring 14 is a circular steel pipe with 8 connecting rings welded on the outer circumference, which is used for the connection of the pile foundation model 4 and the wire rope; 4 are connected by means of energy storage spot welding.

The experimental steps are as follows:

As shown in Figure 2 and Figure 3, when one-way horizontal cyclic loading, one end of the wire rope bypasses the fixed pulley 3, and is connected with the steel ring 14 on the top of the pile foundation model 4 through the tension pressure sensor 7, and the other end of the wire rope is connected to the wheel through the spring 9 The threaded column 12 on 11 is connected; according to different test load requirements, adjust the wire rope to fix the position of the threaded column 12, start the motor 10, and the load displayed by the tension and pressure sensor 7 is the cyclic load. The strain gauge 6, the tensile pressure sensor 7, and the displacement sensor 5 are connected and connected to a computer, so that the deformation data of the pile foundation model 4 during unidirectional horizontal cyclic loading can be recorded.

As shown in Figure 4 and Figure 5, when two-way horizontal cyclic loading is required, an additional spring 9 is required, one end of the spring 9 is connected to the steel ring 14 of the pile foundation, and the other end is connected to the test box 1; The sensor 7 is connected to the steel ring 14 at the top of the pile foundation model 4, and the other end of the steel wire rope is connected to the threaded column 12 on the wheel 11 through a spring 9; according to different test load requirements, the position of the steel wire rope fixed on the threaded column 12 is also different. The load displayed by the motor 10 and the tensile pressure sensor 7 is the size of the cyclic load. The collector is connected to the strain gauge 6, the tensile pressure sensor 7, and the displacement sensor 5 of the pile foundation model 4, and connected to the computer to record bidirectional horizontal cyclic loading. The pile foundation model 4 bears deformation data during this period.

As shown in Figure 6, during vertical cyclic loading, one end of the wire rope on the right side of the spring 9 is connected to the threaded column 12 on the wheel 11, and the thin wire rope at the other end bypasses the fixed pulley 3, and is loaded by pulling the pressure sensor 7 and the weight The rods 8 are connected vertically; according to the design cycle amplitude, a weight of a certain size is counterweighted on the weight loading rod 8, and then the wheel disc 11 is adjusted so that the indication of the pulling pressure sensor 7 and the weight are equal to the weight of the weight loading rod 9 Same, at this moment the top load of the pile foundation model is zero, then set the loading frequency, start the motor 10, the weight of the weight and the weight loading rod 8 is the cyclic load amplitude of the top of the pile foundation model, during the test, through the collector and The strain gauge 6, tension pressure sensor 7, and displacement sensor 5 of the pile foundation model 4 are connected, and connected to a computer, so that the load deformation data of the pile foundation model 4 during vertical cyclic loading can be recorded.

As shown in Figure 7 and Figure 8, when vertical and unidirectional horizontal cyclic loading or multi-directional horizontal cyclic loading, the specific requirements are combined with unidirectional horizontal cyclic loading, bidirectional horizontal cyclic loading and vertical horizontal cyclic loading. Angle β (β is the angle between the connection line between the upper wheel disc of the motor on both sides and the pile foundation, and 0°<β<180°) is placed in combination.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (5)

1. a kind of CYCLIC LOADING system for testing offshore foundation pile-soil interaction, it is characterised in that including unidirectional horizontal cyclic Loading, two-way horizontal CYCLIC LOADING, vertical CYCLIC LOADING, vertically loaded with the loading of unidirectional horizontal cyclic, multidirectional horizontal cyclic, its Middle loading device is by chamber (1), drain bar (2), fixed pulley (3), pile foundation model (4), displacement transducer (5), foil gauge (6), pull pressure sensor (7), counterweight load bar (8), spring (9), motor (10), wheel disc (11), threaded post (12), bottom plate (13), steel loop (14) forms；

Chamber (1) is the uncovered cuboid by angle steel reinforced, and (1) four inwall of chamber sets drain bar (2), drain bar (2) water penetration plank is used, the inwall lower end of chamber (1) is provided with osculum, the soil body used in experiment is loaded in chamber (1)；

Fixed pulley (3) is high-strength alloy by support frame fixed position, fixed pulley (3) material；

Spring (9) both ends respectively connect a seizing wire, and one end seizing wire is directly connected with threaded post (12), the thin steel of the other end Cord bypasses fixed pulley (3), by the upper horizontal of pull pressure sensor (7) and pile foundation model (4) or is vertically connected；

Pile foundation model (4) is partially embedded in the soil body used in experiment, and pile foundation model (4), which is located on the pile lining of soil body part, to be glued Foil gauge (6) is posted, displacement transducer (5) is provided with soil body upper surface, for ease of connecting seizing wire, pile foundation model (4) Stake top and at the 10cm of soil body upper surface weld steel loop (14)；

Motor (10) is variable-speed motor, and motor (10) can realize different rotating speed and moment of torsion under the driving of frequency converter, with The changes in demand of load is adapted to, bottom plate (13) is the rectangular steel plates with bolt installing port；Motor (10) passes through bolt and bottom plate (13) it is connected, motor (10) rotating shaft side placement wheel disc (11), wheel disc (11) is provided with threaded post (12), threaded post (12) and bullet Spring (9) is connected by seizing wire；

Wheel disc (11) is the circular steel plate with multiple bolts hole, and each bolt mouth is different apart from wheel disc (11) circle center distance, spiral shell Line post (12) is the screwed cylindrical steel rods in end, and threaded post (12) can be installed on the different spiral shell of wheel disc (11) by twist-on On bolt mouth；

Steel loop (14) is welded with the round steel pipe of 8 connection rings, the company for pile foundation model (4) and steel wire rope for exterior circumference Connect；Steel loop (14) round steel pipe internal diameter is identical with pile foundation model (4) diameter, is adopted between steel loop (14) and pile foundation model (4) The mode of accumulation of energy spot welding is taken to be attached.

2. a kind of CYCLIC LOADING system for testing offshore foundation pile-soil interaction according to claim 1, its feature exist In when unidirectional horizontal cyclic loads, steel wire rope one end bypasses fixed pulley (3), passes through pull pressure sensor (7) and pile foundation model (4) top steel loop (14) is connected, and the steel wire rope other end is connected by spring (9) with the threaded post (12) on wheel disc (11)； Require different according to finder charge, regulation steel wire rope is fixed on the position of threaded post (12), starts motor (10), pressure sensing Device (7) shows that load is cyclic load size, is sensed by the foil gauge (6) of collector and pile foundation model (4), pressure Device (7), displacement transducer (5) connection, and be connected with computer, you can record pile foundation model during unidirectional horizontal cyclic loading (4) load metamorphism data.

3. a kind of CYCLIC LOADING system for testing offshore foundation pile-soil interaction according to claim 1, its feature exist , need to separately plus a spring (9) when, two-way horizontal CYCLIC LOADING, spring (9) one end is connected to pile foundation steel loop (14), one end Joint test case (1)；Steel wire rope one end bypasses fixed pulley (3), at the top of pull pressure sensor (7) and pile foundation model (4) Steel loop (14) is connected, and the steel wire rope other end is connected by spring (9) with the threaded post (12) on wheel disc (11)；According to experiment Load requirement difference is tested, it is also different that steel wire rope is fixed on threaded post (12) position, starts motor (10), pull pressure sensor (7) Load is cyclic load size, passes through the foil gauge (6) of collector and pile foundation model (4), pull pressure sensor (7), position Displacement sensor (5) connects, and is connected with computer, you can pile foundation model (4) carries during record two-way horizontal CYCLIC LOADING Deformation data.

4. a kind of CYCLIC LOADING system for testing offshore foundation pile-soil interaction according to claim 1, its feature exist When, vertical CYCLIC LOADING, steel wire rope one end on the right side of spring (9) is connected with the threaded post (12) on wheel disc (11), another End seizing wire bypasses fixed pulley (3), is vertically connected with counterweight load bar (8) by pull pressure sensor (7)；According to design Amplitude a certain size counterweight of counterweight on counterweight load bar (8) is circulated, then adjusting wheel disc (11) makes pull pressure sensor (7) Registration and counterweight it is identical with counterweight load bar (9) weight, at this moment pile foundation model top loading carry be zero, then set loading frequency Rate, starts motor (10), and the weight of counterweight and counterweight load bar (8) is the cyclic load amplitude on pile foundation model top, experiment When, it is connected by collector with foil gauge (6), pull pressure sensor (7), the displacement transducer (5) of pile foundation model (4), and It is connected with computer, you can record pile foundation model (4) load metamorphism data during vertical CYCLIC LOADING.

5. a kind of CYCLIC LOADING system for testing offshore foundation pile-soil interaction according to claim 1, its feature exist In, vertically with unidirectional horizontal cyclic loading or multidirectional horizontal cyclic load, specific requirement combine unidirectional horizontal cyclic loading, it is two-way (β is wheel disc and stake on the motor of both sides according to angle beta for three sets of horizontal cyclic loading, vertical levels CYCLIC LOADING CYCLIC LOADING devices The angle of the line on basis, and 0 °<β<180 °) combination placement.