Test device and test method for horizontal bearing capacity and rotation center of multi-barrel foundation

Abstract

The present invention discloses a test device and a test method for the horizontal bearing capacity and rotation center of a multi-barrel foundation. The test device comprises: a test box with an opening at the top and filled with test soil; a reaction frame across the top of the test box; two auxiliary beams fixedly installed perpendicular to the top cross beam of the reaction frame; a multi-barrel foundation installed in the soil in the test box; a servo electric cylinder fixedly installed on a column on one side of the reaction frame; two vertical pull-wire displacement sensors respectively installed on the auxiliary beams and two horizontal pull-wire displacement sensors arranged up and down. The present invention can obtain the bearing capacity of the multi-barrel foundation under the action of horizontal load and the motion trajectory of the rotation center of the multi-barrel foundation.

Description

Technical Field

[0001] The invention relates to the field of engineering technology, and in particular to a testing device and a testing method for the horizontal bearing capacity and rotation center of a multi-barrel foundation. Background Art

[0002] Bucket foundations are widely adaptable to water depth and geological conditions, have fast construction, and have low requirements for construction equipment. In view of the superiority of bucket foundations in transportation, construction, load bearing and cost, many wind farms have been applied abroad, and my country's offshore wind power field has gradually begun to adopt multi-bucket foundations. As an offshore wind power foundation structure, multi-bucket foundations need to withstand horizontal loads such as wind, waves and currents. Under extreme conditions, horizontal loads can reach 60% of the vertical load. Therefore, bearing horizontal loads is an important feature of the foundation structure in the offshore wind power field. There are complex interactions between multi-bucket foundations and soil under horizontal loads, and there is currently no unified calculation method. On the other hand, multi-bucket foundations rotate under horizontal loads, and their anti-overturning ability is related to the position of the rotation center. The determination of the rotation center is still under exploration. For the above problems, model tests are the most intuitive and effective way. For this purpose, a set of test devices for obtaining the horizontal bearing capacity and rotation center position of multi-bucket foundations needs to be designed, and a rotation center calculation method is proposed. Summary of the invention

[0003] The purpose of the present invention is to solve the above-mentioned problems and to provide a test device and a test method for the horizontal bearing capacity and rotation center of a multi-bucket foundation, which can be used to test the bearing capacity of the multi-bucket foundation under horizontal loads and the motion trajectory of the rotation center of the multi-bucket foundation.

[0004] The object of the present invention is achieved in that:

[0005] A testing device for the horizontal bearing capacity and rotation center of a multi-barrel foundation of the present invention comprises:

[0006] A test box with an open top, filled with test soil;

[0007] A reaction frame across the top of the test box, and two auxiliary beams fixedly installed perpendicular to the top crossbeam of the reaction frame;

[0008] A multi-barrel foundation placed in the soil of the test box, the multi-barrel foundation comprising four negative pressure barrels arranged in an array, a guide tube frame with a lower end welded to the center of the tops of the four negative pressure barrels, and a loading platform welded to the top of the guide tube frame, wherein the guide tube frame comprises a plurality of vertical rods and a horizontal rod connecting the plurality of vertical rods;

[0009] A servo electric cylinder fixedly installed horizontally on a side column of the reaction frame, and the push rod of the servo electric cylinder can be extended and retracted horizontally;

[0010] A loading plate disposed longitudinally along the center line of the loading platform and vertically fixed on the loading platform;

[0011] Two vertical pull-wire displacement sensors are respectively mounted on the auxiliary beams, the pull ropes of the vertical pull-wire displacement sensors are extended vertically downward, and the pull rope ends are respectively connected to the top centers of two negative pressure barrels parallel to the horizontal loading direction; and

[0012] Two horizontal pull-wire displacement sensors are arranged up and down, wherein the upper horizontal pull-wire displacement sensor is consistent with the center height of the loading plate and the pull rope head of the pull rope is connected to the center of the loading plate, and the lower horizontal pull-wire displacement sensor is consistent with the center height of the cross bar of the catheter frame and the pull rope head is connected to the center of the cross bar.

[0013] The reaction frame in the above-mentioned test device for the horizontal bearing capacity and rotation center of the multi-barrel foundation is a portal frame structure composed of three I-beams.

[0014] In the above-mentioned test device for the horizontal bearing capacity and rotation center of the multi-barrel foundation, two horizontal pull-wire displacement sensors are fixedly installed on the other side column of the reaction frame.

[0015] The present invention provides a test method for a test device for the horizontal bearing capacity and rotation center of a multi-barrel foundation, comprising the following steps:

[0016] (1) Estimate the horizontal bearing capacity of the multi-barrel foundation using a single-cycle continuous loading method, with each load not exceeding 1 / 10 of the estimated horizontal ultimate bearing capacity and maintained for 30 min;

[0017] (2) Use a servo electric cylinder to load the multi-barrel foundation horizontally. After each level of load is applied, measure the values ​​of the horizontal and vertical pull-wire displacement sensors at 1 min, 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min respectively;

[0018] (3) The test ends when the maximum horizontal displacement of the top of the negative pressure barrel reaches 3% to 6% of the diameter of the negative pressure barrel or the horizontal displacement of the multi-barrel base increases while the load value of the servo electric cylinder remains unchanged or decreases.

[0019] In the test method for the test device for the horizontal bearing capacity and rotation center of the multi-barrel foundation, the horizontal distance between the rotation center of the multi-barrel foundation and the center of the front negative pressure barrel in the horizontal loading direction under the i-th level horizontal load is x i :

[0020]

[0021] Where: S a is the horizontal distance between two vertical wire displacement sensors, a 1i 、a2i are the vertical displacements of the two vertical wire-type displacement sensors under the i-th level load.

[0022] In the test method for the test device for the horizontal bearing capacity and rotation center of the multi-barrel foundation, the vertical distance between the rotation center of the multi-barrel foundation and the crossbar of the multi-barrel foundation jacket under the i-th level horizontal load is y i :

[0023]

[0024] Where: S b is the height difference between the two horizontal wire displacement sensors, b 1i , b 2i are the displacements of the two horizontal wire-type displacement sensors under the i-th level load.

[0025] The invention can obtain the bearing capacity of the multi-barrel foundation under the action of horizontal load and the motion track of the rotation center of the multi-barrel foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of a test device for the horizontal bearing capacity and rotation center of a multi-barrel foundation according to the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the multi-barrel foundation of the present invention;

[0028] Figure 3 is a state diagram of a multi-barrel basic test of the present invention (the dotted line is after loading);

[0029] Figure 4 It is a schematic diagram of displacement calculation of the multi-barrel foundation of the present invention under horizontal load;

[0030] Figure 5 It is a schematic diagram of calculating the rotation center of the multi-barrel foundation of the present invention under horizontal load. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] See also Figures 1-2 , the figure shows a test device for the horizontal bearing capacity and rotation center of a multi-barrel foundation of the present invention, comprising:

[0033] A test box 1 with an open top, wherein the test box 1 is filled with test soil 11;

[0034] A reaction frame 2 spanning the top of the test box 1. In this embodiment, the reaction frame 2 is a door-shaped frame structure composed of three I-beams;

[0035] Two auxiliary beams 3 are arranged longitudinally and fixedly installed perpendicular to the top cross beam of the reaction frame 2;

[0036] A multi-barrel foundation 4 is placed in the test box 1, and the multi-barrel foundation 4 includes a horizontally arranged loading platform 41, a guide tube frame 42 for supporting the bottom of the loading platform 41, and four negative pressure barrels 43 arranged in an array, the lower end of the guide tube frame 42 is welded to the center of the top of the negative pressure barrel 43, and two negative pressure barrels 43 arranged in the same direction are located vertically below the same auxiliary beam 3; in this embodiment, the guide tube frame 42 is composed of four vertical rods and four horizontal rods;

[0037] A loading plate 44 disposed longitudinally along the center line of the loading platform 41 and fixedly mounted perpendicularly thereto;

[0038] A servo electric cylinder 5 is fixedly mounted on a side column of the reaction frame 2, and a push rod of the servo electric cylinder 5 is horizontally extended to the left to load the loading plate 44, and the horizontal loading direction of the servo electric cylinder 5 is perpendicular to the loading plate 44;

[0039] Two vertical pull-wire displacement sensors 6 respectively mounted on the two auxiliary beams 3 and respectively located vertically above the two negative pressure barrels 43, the pull ropes of the vertical pull-wire displacement sensors 6 vertically extend downward and are respectively connected to the top centers of the two negative pressure barrels 43 parallel to the horizontal loading direction of the servo electric cylinder 5; and

[0040] Two horizontal pull-wire displacement sensors 7 are arranged up and down, wherein the upper horizontal pull-wire displacement sensor 7 is consistent with the center height of the loading plate 44 and the pull rope head of the pull rope is connected to the center of the loading plate 44; the pull rope of the lower horizontal pull-wire displacement sensor 7 is consistent with the center height of the cross bar of the catheter frame 42 and the pull rope head is connected to it.

[0041] See also Figure 3-5 The test method of the test device for the horizontal bearing capacity and rotation center of a multi-barrel foundation of the present invention comprises the following steps:

[0042] (1) Estimate the horizontal bearing capacity of multi-barrel foundation 4 using a single cycle continuous loading method, with each load not exceeding 1 / 10 of the estimated horizontal ultimate bearing capacity and maintained for 30 min;

[0043] (2) The servo electric cylinder 5 applies horizontal load to the multi-barrel foundation 4. After each level of load is applied, the values ​​of the horizontal pull-wire displacement sensor and the vertical pull-wire displacement sensor are measured at 1 min, 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min respectively;

[0044] (3) When the maximum horizontal displacement value x of the top of the negative pressure barrel 43 reaches 3% to 6% of the diameter of the negative pressure barrel 43, or the horizontal displacement of the multi-barrel base 4 increases while the load value of the servo electric cylinder 5 remains unchanged or decreases, the test ends;

[0045] See also Figure 4 , under the i-th level horizontal load, the rotation center of the multi-barrel foundation 4 and the negative pressure barrel 43 (i.e. Figure 3 The horizontal distance between the center of the negative pressure barrel 43) on the left side is x i :

[0046]

[0047] Among them, S a is the horizontal distance between two vertical wire-type displacement sensors 6, a 1i 、a 2i are respectively the vertical displacements of the two vertical wire-type displacement sensors 6 under the i-th level load;

[0048] See also Figure 5 , the vertical distance between the rotation center of the multi-barrel foundation 4 and the crossbar of the jacket 42 of the multi-barrel foundation 4 under the i-th level horizontal load is y i :

[0049]

[0050] Among them, S b is the height difference between the two horizontal wire-type displacement sensors 7, b 1i , b 2i They are respectively the displacements of two horizontal wire-type displacement sensors 7 under the i-th level load.

[0051] During the test, the horizontal load value of the servo electric cylinder 5, the displacement values ​​of the horizontal pull-wire displacement sensor 7 and the vertical pull-wire displacement sensor 6 are continuously recorded to obtain the horizontal load-horizontal displacement curve (i.e., FS curve), and the motion trajectory of the rotation center is calculated.

[0052] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A test device for the horizontal bearing capacity and rotation center of a multi-barrel foundation, characterized in that: It includes: A test box with an open top, filled with test soil; A reaction frame across the top of the test box, and two auxiliary beams fixedly installed perpendicular to the top crossbeam of the reaction frame; a multi-barrel foundation placed in the soil of the test box, the multi-barrel foundation comprising four negative pressure barrels arranged in an array, a pipe frame with a lower end welded to the center of the top of the four negative pressure barrels, and a loading platform welded to the top of the pipe frame, the pipe frame comprising a plurality of vertical rods and a horizontal rod connecting the plurality of vertical rods; A servo electric cylinder fixedly installed laterally on a side column of the reaction frame, wherein the push rod of the servo electric cylinder can be extended and retracted horizontally; A loading plate disposed longitudinally along the center line of the loading platform and vertically fixed on the loading platform; Two vertical pull-wire displacement sensors are respectively mounted on the auxiliary beams, the pull ropes of the vertical pull-wire displacement sensors are retracted vertically downward, and the pull rope ends of the pull ropes are respectively connected to the top centers of the two negative pressure barrels parallel to the horizontal loading direction; and Two horizontal pull-wire displacement sensors are arranged up and down, wherein the upper horizontal pull-wire displacement sensor is consistent with the center height of the loading plate and the pull rope head of the pull rope is connected to the center of the loading plate, and the lower horizontal pull-wire displacement sensor is consistent with the center height of the cross bar of the catheter frame and the pull rope head is connected to the center of the cross bar.

2. The test device for the horizontal bearing capacity and rotation center of a multi-barrel foundation as claimed in claim 1, characterized in that: The reaction frame is a portal frame structure composed of three I-beams.

3. The testing device for the horizontal bearing capacity and rotation center of a multi-barrel foundation as claimed in claim 1, characterized in that: The two horizontal pull-wire displacement sensors are fixedly mounted on the other side column of the reaction frame.

4. A test method for the test device for the horizontal bearing capacity and rotation center of a multi-barrel foundation as claimed in claim 1, characterized in that: The following steps are involved: (1) Estimate the horizontal bearing capacity of the multi-barrel foundation by using a single-cycle continuous loading method, with each load not exceeding 1 / 10 of the estimated horizontal ultimate bearing capacity and maintained for 30 minutes; (2) The multi-barrel foundation is horizontally loaded using the servo electric cylinder, and the values ​​of the horizontal pull-wire displacement sensor and the vertical pull-wire displacement sensor are measured at 1 min, 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min after each level of load is applied; (3) The test ends when the maximum horizontal displacement value of the top of the negative pressure barrel reaches 3% to 6% of the diameter of the negative pressure barrel or the horizontal displacement of the multi-barrel base increases while the load value of the servo electric cylinder remains unchanged or decreases; The horizontal distance between the rotation center of the multi-barrel foundation and the center of the front negative pressure barrel in the horizontal loading direction under the i-th level horizontal load is x. i : Where: a is the horizontal distance between the two vertical wire-type displacement sensors, a 1i 、a 2i are respectively the vertical displacements of the two vertical wire-type displacement sensors under the i-th level load; The vertical distance between the rotation center of the multi-barrel foundation and the crossbar of the multi-barrel foundation jacket under the i-th level horizontal load is y i : Where: b is the height difference between the two horizontal wire displacement sensors, b 1i , b 2i They are respectively the displacements of the two horizontal wire-type displacement sensors under the i-th level load.

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