A saturated soft clay consolidation apparatus

Abstract

The application belongs to the technical field of geotechnical engineering test, and discloses a saturated soft clay consolidation device, which comprises a pressurizing frame, a model box for containing clay is arranged in the pressurizing frame, and the model box is sequentially sealed and connected by an upper box body, a lower box body and a base from top to bottom; the base supports the model box on the bottom crossbeam of the pressurizing frame through a bearing crossbeam; a lifting adjusting mechanism is arranged at the bottom of the pressurizing frame, and the lifting adjusting mechanism is used for adjusting the height of the pressurizing frame; an electric cylinder is fixedly installed at the top of the pressurizing frame, and a pressure transmission plate is connected to the bottom of the electric cylinder; the electric cylinder is connected with a controller through a servo motor and a servo driver; the controller is used for controlling the servo motor to operate through the servo driver, so that the servo motor drives the electric cylinder to move up and down and applies pressure on the soil body in the model box through the pressure transmission plate. The application can prepare soil samples with different consolidation degrees, and ensure that the quantity is sufficient and the physical and mechanical properties are consistent before and after.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geotechnical engineering test, in particular, relates to a saturated soft soil and super soft soil sample preparation device in geotechnological model test and unit test, and especially relates to a saturated soft clay sample preparation device for large-scale physical model test of different scales on the seabed. BACKGROUND

[0002] In recent years, people's utilization of marine resources is increasing, such as building offshore oil and gas platforms, offshore wind power generation, etc. Most of the marine engineering relies on solid foundation. In order to ensure the safety, reliability and economy of the engineering, the properties of seabed soil interacting with the foundation need to be fully understood.

[0003] The seabed soil is usually saturated soft clay. For seabed soft soil and super soft soil, especially the soil sample in the deep sea area, it has the characteristics of low strength, high water content, high sensitivity, strong structure, normal consolidation or slight over-consolidation. However, direct sampling of seabed soft soil for indoor test will inevitably cause deviation due to disturbance to the soil sample, and the cost of sampling and transportation is also very expensive.

[0004] Therefore, it is necessary to obtain soil samples with the characteristics of saturated soft clay on the seabed through laboratory sample preparation. Geotechnological test obtains various physical and mechanical indexes of soil samples through test and observation of soil samples. In order to make the geotechnological test results have sufficient accuracy and reliability, the accuracy, uniformity and repeatability of the test object, i.e. the soil sample, must be ensured. SUMMARY

[0005] Based on the need to understand the characteristics of deep-sea saturated soft clay and meet the requirements of engineering and scientific research, the present application aims to solve the technical problem of how to prepare a large amount of saturated soft clay with low strength, high water content, high sensitivity, strong structure, normal consolidation or slight over-consolidation. The present application provides a saturated soft clay consolidation device which can prepare soil samples with different consolidation degrees and ensure sufficient quantity and consistent physical and mechanical properties before and after.

[0006] In order to solve the above technical problems, the present application is realized by the following technical scheme:

[0007] The application provides a saturated soft clay consolidation device, which comprises a pressurizing frame, a model box arranged in the pressurizing frame and used for containing clay, and a bottom plate and a plurality of steel sleeper beams connected to the bottom plate.

[0008] The bottom of the pressurizing frame is provided with a lifting adjusting mechanism for adjusting the height of the pressurizing frame from the ground, so that the bearing cross beam fixed to the bottom cross beam of the pressurizing frame contacts the bottom plate.

[0009] The top of the pressurizing frame is fixedly provided with an electric cylinder, the bottom of the electric cylinder is connected with a pressure transmission plate, and the bottom of the pressure transmission plate is provided with a flat surface for applying pressure.

[0010] Further, the pressurizing frame is a cubic frame structure and comprises at least four top cross beams, four bottom cross beams, four vertical columns and a plurality of inclined braces.

[0011] Further, at least one of the bottom cross beams of the pressurizing frame is arranged as a detachable movable cross beam, the movable cross beam is removed and pushed into the pressurizing frame, so that the model box can enter the inside of the pressurizing frame.

[0012] Further, the bottom of the pressurizing frame is provided with a rolling wheel, and the rolling wheel can make the pressurizing frame walk under the pushing.

[0013] Further, the upper box body and the lower box body are both surrounded by four side wall steel plates connected in sequence, and each side wall steel plate is externally provided with a reinforcing rib.

[0014] Further, the upper box body and the lower box body, the lower box body and the bottom plate are connected and fixed through flanges, and are sealed by rubber water stop at the connecting joints.

[0015] Further, the bottom plane size of the pressure transmission plate is slightly smaller than the opening size of the upper box body and the lower box body.

[0016] Further, the electric cylinder is configured with a pressure sensor for feeding the detected pressurized pressure into the controller, and the controller accurately controls the electric cylinder according to the pressurized pressure.

[0017] The beneficial effects of the present application are:

[0018] The saturated soft clay consolidation device provided by the present application designs the loading pressure as the internal force of the pressurizing frame; when pressurizing, the pressurizing frame is subjected to the upward reaction force from the pressure transmission plate and the downward reaction force from the two bearing cross beams at the bottom of the pressurizing frame, forming a pressure closed loop; thus, the device only bears the self weight of the device, and therefore, the infrastructure requirement of the test site is low, and theoretically, infinite pressure can be applied to the soil without affecting the surrounding site.

[0019] When the saturated soft clay is delivered to the model box, the device can be automatically controlled, i.e., the consolidation is performed according to the pre-set parameters such as loading pressure, rate and time, and in addition, the device can be remotely controlled and the test data can be read under networking conditions.

[0020] The model box is composed of an upper box body and a lower box body, and the soil quantity can be flexibly adjusted according to the test requirements, thereby reducing the workload and time and improving the test efficiency.

[0021] The pressure control system built in the pressurizing device can accurately control the load of the pressure transmission plate acting on the soil, thereby ensuring the consolidation accuracy of the soil sample. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The structure schematic view of the saturated soft clay consolidation device provided by the present application is shown in the figure.

[0023] Figure 2 The structure schematic view of the pressurizing frame in the saturated soft clay consolidation device provided by the present application is shown in the figure.

[0024] Figure 3 The structure schematic view of the model box in the saturated soft clay consolidation device provided by the present application is shown in the figure.

[0025] Figure 4 The time-load-displacement curve of the saturated clay in the embodiment under the constant pressure of 30kN is shown in the figure; wherein, (a) is the time-load curve, and (b) is the time-displacement curve.

[0026] In the above figure: 1-pressure control system; 2-pressurized frame; 3-model box; 4-controller; 5-pressure transmission plate; 6-lifting adjustment mechanism; 7-bearing crossbeam; 8-roller; 9-servo driver; 10-servo motor; 11-electric cylinder; 12-pressure sensor; 13-movable crossbeam; 14-bottom crossbeam; 15-upper box body; 16-lower box body; 17-side wall steel plate; 18-stiffener; 19-base; 20-steel sleeper; 21-flange plate; 22-bottom plate. DETAILED DESCRIPTION

[0027] In order to further understand the content, characteristics and effects of the present application, the following examples are given, and the details are described as follows with reference to the accompanying drawings:

[0028] As shown in Figure 1 , the embodiment provides a saturated soft clay consolidation device, which comprises a pressure control system 1, a pressurized frame 2 and a model box 3.

[0029] The pressure control system 1 is composed of a controller 4, a servo driver 9, a servo motor 10 and an electric cylinder 11. The controller 4 is fixed on the pressurized frame 2, and the controller 4 is used to program and set the pressurization parameters and send control instructions to the servo driver 9, so as to control the operation of the servo motor 10 through the servo driver 9 and drive the electric cylinder 11 to move up and down. The electric cylinder 11 is connected with a pressure transmission plate 5 at the bottom, and the bottom of the pressure transmission plate 5 is provided with a plane for applying pressure, so as to apply pressure to the soil body in the model box 3 through the pressure transmission plate 5. The head of the electric cylinder 11 is provided with a pressure sensor 12, which is used to feed back the detected pressurization pressure to the controller 4, so as to realize accurate pressure control of the controller 4.

[0030] The pressure control system 1 can adjust the parameters in real time to control the consolidation of the soil body through the controller 4, or can consolidate according to the pre-set loading parameters. The controller 4 can input the pressurization parameters through a touch screen or an external keyboard, or can realize remote control and monitoring under networked conditions. During the process of pressure loading, the relevant data (including time, displacement and load, etc.) will be recorded in the controller 4 in the form of csv file format according to the pre-set reading interval, and the recording content is simple and clear, which is convenient for analysis and use.

[0031] As shown in Figure 2As shown, the pressurized frame 2 is a movable cubic frame structure, including at least four top cross beams, four bottom cross beams 14, four vertical columns and several diagonal braces; the pressurized frame 2 can accommodate the model box 3. The electric cylinder 11 is fixed to the top center of the pressurized frame 2 by flange connection. Four wheels are arranged at the bottom corners of the pressurized frame 2, which can make the pressurized frame 2 walk under the power of manpower. The bottom of the pressurized frame 2 is also provided with a lifting adjusting mechanism 6, which is fixed to the bottom surface of the bottom cross beam 14. The height of the pressurized frame 2 from the ground can be adjusted through the lifting adjusting mechanism 6.

[0032] At least one of the bottom cross beams 14 of the pressurized frame 2 is provided as a movable cross beam 13, which can be detached. After the movable cross beam 13 is removed, the pressurized frame 2 can be pushed forward and the model box 3 can be located in the center of the pressurized frame 2.

[0033] Two bearing cross beams 7 are arranged at the bottom of the pressurized frame 2. After the two bearing cross beams 7 are transversely arranged through the steel sleeper 20 of the model box 3, they are respectively arranged on the two bottom cross beams 14 of the pressurized frame 2 and fixed to the bottom cross beams 14 by bolts, so as to connect the model box 3 and the pressurized frame 2.

[0034] As shown, Figure 3 The model box 3 is composed of an upper box body 15, a lower box body 16 and a base 19. The upper box body 15 and the lower box body 16 are both box structures with upper and lower openings, which are used for containing clay. The upper box body 15 and the lower box body 16 are both surrounded by four side wall steel plates 17 connected in sequence, and each side wall steel plate 17 is provided with a reinforcing rib 18 outside. According to the amount of test soil, the lower box body 16 can be replaced by a support of the same size. The base 19 is composed of a bottom plate 22 and a plurality of steel sleepers 20; the bottom plate 22 is connected to the bottom of the lower box body 16 and used for closing the upper box body 15 and the lower box body 16; the plurality of steel sleepers 20 are arranged at intervals, and each steel sleeper 20 is provided with two recesses, which are slightly larger than the cross section of the bearing cross beam 7, so that the bearing cross beam 7 can pass through, so as to support the model box 3 on the pressurized frame 2. The upper box body 15 and the lower box body 16, and the lower box body 16 and the base 19 are connected and fixed by flanges 21, and rubber waterstops are arranged at the joints.

[0035] The size of the pressure transmission plate 5 in the pressure control system 1 should be slightly smaller than the opening size of the upper box body 15 and the lower box body 16 in the model box 3, which can ensure that the pressure transmission plate 5 can be smoothly pressed into the upper box body 15 or the lower box body 16, and the soil body can be uniformly pressed.

[0036] The soil sample is prepared by using the above saturated soft clay consolidation device, and the specific steps are as follows:

[0037] Firstly, lay sand on the bottom plate 22 of the model box 3, then lay water-permeable geotextile on the sand surface and the inner wall of the model box 3, and inject a certain amount of water. Inject the pre-vacuumized saturated soft clay into the model box 3, and ensure that there is no air in the soil body below the water surface during the whole process of discharging the mud.

[0038] Remove the movable cross beam 13 of the pressurizing frame 2, push the pressurizing frame 2 to the inside center position of the model box 3, and reassemble the movable cross beam 13. Pass the bearing cross beam 7 through the steel sleeper 20 of the base 19, and make the bearing cross beam 7 rest on the two parallel bottom cross beams 14 of the pressurizing frame 2, and fix the bearing cross beam 7 and the bottom cross beams 14 with bolts. Adjust the lifting adjusting mechanism 6 of the pressurizing frame 2, and lift the height of the pressurizing frame 2, so that the upper surface of the bearing cross beam 7 contacts the bottom plate 22.

[0039] Input the pressurizing number parameter into the controller 4 and start, the controller 4 sends a control command to the servo driver 9, the servo driver 9 controls the servo motor 10 to run and drives the electric cylinder 11 to move downward. The electric cylinder 11 applies pressure to the soil body in the model box 3 through the pressure transmission plate 5 until the soil body reaches the expected consolidation degree.

[0040] Due to the adoption of servo control, the whole pressurizing process can be monitored, and the pressurizing parameters and the equipment movement state can be fed back to the controller 4 in real time, and displayed on the touch screen. When faults such as overload, overstroke, overspeed, overheating and broken wire occur, the controller 4 will issue an alarm and stop running, ensuring the safety of the equipment.

[0041] After the consolidation is completed, the controller 4 is instructed to lift the electric cylinder 11 to separate the pressure transmission plate 5 from the soil body in the model box 3. Adjust the lifting adjusting mechanism 6 to make the rollers 8 of the pressurizing frame 2 touch the ground, pull out the bearing cross beam 7, remove the movable cross beam 13, push the pressurizing frame 2 away from the model box 3, assemble the movable cross beam 13, adjust the lifting adjusting mechanism 6 to make the rollers 8 off the ground to keep the pressurizing frame 2 stable and avoid accidental movement.

[0042] After the test is completed, the controller 4 and the electric cylinder 11 are turned off in sequence, and the test data is arranged, and a typical test loading curve can be obtained as shown in Figure 4 .

[0043] Although the preferred embodiments of the present application are described above in combination with the drawings, the present application is not limited to the specific embodiments described above, and the specific embodiments described above are only illustrative and not restrictive. Those skilled in the art can make many specific changes to the embodiments under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection scope of the present application.

Claims

1. A saturated soft clay consolidation apparatus, characterized by, The application relates to a pressure frame, which is internally provided with a model box for containing clay; the model box is sealedly connected by an upper box body, a lower box body and a base from top to bottom; the upper box body and the lower box body are both open at the top and bottom; the upper box body and the lower box body are fixedly connected through flanges, and the connection joints are sealed by rubber; the base comprises a bottom plate and a plurality of steel sleepers connected to the bottom plate; the bottom plate is connected to the bottom surface of the lower box body; the steel sleepers are arranged at intervals on the bottom of the bottom plate; each steel sleeper is provided with two grooves for bearing cross beams; the bearing cross beams are used for supporting the model box on the bottom cross beam of the pressure frame, and the two ends of the bearing cross beams are fixed to the bottom cross beam of the pressure frame through bolts. The bottom of the pressure frame is provided with a lifting adjusting mechanism for adjusting the height of the pressure frame from the ground, so that the bearing cross beam fixed to the bottom cross beam of the pressure frame contacts the bottom plate. The top of the pressure frame is fixedly provided with an electric cylinder, the bottom of the electric cylinder is connected with a pressure transmission plate, the bottom of the pressure transmission plate is provided with a flat surface for applying pressure; the bottom flat surface of the pressure transmission plate is slightly smaller than the opening size of the upper box body and the lower box body; the electric cylinder is connected with a servo motor, the servo motor is connected with a servo driver, and the servo driver is connected with a controller; the controller is used for controlling the servo motor to run through the servo driver, so that the servo motor drives the electric cylinder to move up and down and applies pressure to the soil in the model box through the pressure transmission plate.

2. The saturated soft clay consolidating apparatus according to claim 1, wherein The pressure frame is a cubic frame structure, and at least comprises four top cross beams, four bottom cross beams, four vertical columns and a plurality of inclined braces.

3. The saturated soft clay consolidating apparatus according to claim 2, wherein At least one of the bottom cross beams of the pressure frame is arranged as a detachable movable cross beam, the movable cross beam is removed and pushed into the pressure frame, so that the model box can enter the inside of the pressure frame.

4. The saturated soft clay consolidating apparatus according to claim 1, wherein The bottom of the pressure frame is provided with a roller, and the roller can make the pressure frame walk under the pushing.

5. The saturated soft clay consolidating apparatus according to claim 1, wherein The upper box body and the lower box body are both surrounded by four side wall steel plates connected in sequence, and each side wall steel plate is externally provided with a reinforcing rib.

6. The saturated soft clay consolidating apparatus according to claim 1, wherein The electric cylinder is provided with a pressure sensor, the pressure sensor is used for feeding back the detected pressure to the controller, and the controller accurately controls the electric cylinder according to the pressure.

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