Open caisson anti-drag material testing system and testing method

Abstract

The invention provides an open caisson anti-drag material testing system which comprises a testing platform, a soil containing device arranged on the testing platform and used for containing a soil body sample, a test piece block capable of moving by being attached to the soil body sample and an anti-drag material arranged on the contact face of the test piece block and the soil body sample. A test system similar to a field working condition is constructed to assist in measuring and selecting a drag reduction material with the most excellent drag reduction performance; and a plurality of test channels are adopted, so that various different materials can be tested at the same time, and the test efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of caisson sinking tests, and in particular to a caisson drag reduction material testing system and a testing method. Background Art

[0002] At present, the construction of large-span bridges across rivers is mainly based on suspension bridges. As an important part of the bridge foundation, the anchor foundation plays a vital role in the safe operation of the bridge. At present, the anchor foundation of the suspension bridge is mainly composed of caisson and ground-connected wall structure. Among them, the caisson has become the preferred solution for bridge foundation due to its high overall structural rigidity, good stability and low cost.

[0003] During the construction process, caissons often face the risk of sudden sinking or difficulty in sinking, which is mainly closely related to the geological conditions. When the geological conditions are poor, especially the deep silt strata, the silt soil layer wraps the outer wall of the caisson as a whole, and the soil itself has a large cohesion, which makes the caisson sinking construction very likely to be difficult to sink. In the face of this situation, conventional conditions mainly use weighting, mud jackets, air curtains, high-pressure water jetting, sand filling and drag reduction well construction methods to reduce the frictional resistance between the well wall and the soil and thus assist in the sinking of the caisson. At present, the mud jacket construction method is more common and more mature in combination with the on-site construction conditions. At present, the mud jacket mainly uses bentonite, soda ash, CMC and other materials. The main principle is that the mud produces a layer of mud film on the side wall to ensure isolation between the well wall and the soil, reduce the side friction of the caisson wall, and then the caisson uses its own weight to sink.

[0004] However, if poor geological conditions are encountered during the caisson sinking construction process, conventional mud jacket drag reduction technology cannot meet the caisson sinking construction requirements. Therefore, it is necessary to develop new drag reduction materials to meet the construction requirements. However, there are currently new drag reduction materials that cannot be tested for their drag reduction properties by existing devices. Therefore, it is urgent to use an indoor measuring device for quickly testing the friction coefficient of drag reduction materials to measure the drag reduction properties of drag reduction materials, and then select the drag reduction material that is most suitable for caisson sinking, to help the caisson sink smoothly in deep silty clay. Summary of the invention

[0005] The invention provides a caisson drag reduction material testing system and a testing method, which solve the problem of drag reduction performance testing of drag reduction materials used for sinking caissons.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a caisson drag reduction material testing system, including a testing platform, a soil holding device is provided on the testing platform, the soil holding device is used to place soil samples, a test block that can stick to the soil sample and move, and a drag reduction material is provided. The drag reduction material is used to be arranged at the contact surface between the test block and the soil sample.

[0007] In a preferred solution, a first guide rail is provided on one side of the soil container on the test platform, a mobile platform is provided on the first guide rail, a force sensor is provided on the mobile platform, a pull rope is provided at one end of the force sensor, and one end of the pull rope is connected to the specimen block.

[0008] In a preferred solution, an inclined groove platform is provided on the test platform, a plurality of separated linear grooves are provided in the groove platform, a soil containing device is provided in each linear groove, and the lower end of the soil containing device is open.

[0009] In the preferred scheme, a slurry inlet hole is provided at the upper end of the specimen block, a branch channel connected to the slurry inlet hole is provided in the slurry inlet hole, a plurality of slurry outlet holes are provided on the contact surface between the specimen block and the soil sample, each slurry outlet hole is connected to the branch channel, and a carrying frame movable along the length direction of the straight groove is also provided on the groove platform, a plurality of slurry bottles are provided on the carrying frame, and a flexible tube is also provided, and the lower end of the slurry bottle is connected to the slurry inlet hole through the flexible tube.

[0010] In the preferred solution, a plurality of force sensors are provided on the side of the mounting frame close to the flexible tube, a tube clamping frame is provided at one end of each force sensor, each tube clamping frame is sleeved on the upper end of each flexible tube, a linear drive cylinder is provided on one side of the groove platform, and the rod end of the linear drive cylinder is connected to the mounting frame.

[0011] In the preferred solution, a fixed pulley is provided at the lower end of the groove platform, and a pull rope is also provided. The pull rope is passed around the fixed pulley, a traction block is provided at one end of the pull rope, and the other end of the pull rope is connected to the front end of the specimen block. A pull-wire displacement sensor is provided at the higher end of the groove platform, and the pull wire of the pull-wire displacement sensor is connected to the rear end of the specimen block.

[0012] In the preferred solution, a first hinged seat and a second guide rail are provided at the lower end of the groove platform, a front support and a rear support are provided on the test platform, the front support is hinged at the first hinged seat, a telescopic rod is provided in the rear support, a second hinged seat is provided at the upper end of the telescopic rod, the second hinged seat is slidably connected to the second guide rail, and a spring balancer is also provided on the groove platform, which pulls the rear end of the specimen block.

[0013] In the preferred solution, the soil holding device is a U-shaped structure, and outward flanges are provided on both sides of the open end of the U-shaped structure, and multiple flanges are arranged at intervals. Multiple splicing blocks are provided at the bottom end of the soil holding device, and the splicing blocks are provided with raised baffles arranged in an alternating manner.

[0014] In the preferred scheme, a third guide rail is provided at both ends of the groove platform, and both ends of the carrying frame are slidably connected to the third guide rail. A slidable slide rod is provided at both ends of the carrying frame, and a contact foot with a threaded connection is provided at one end of the slide rod. Friction strips are provided at both ends of the groove platform, and the contact foot slides against the friction strip. A stop nut is provided at the end of the slide rod away from the groove platform, a first spring is provided between the contact foot and the carrying frame, and a second spring is provided between the stop nut and the carrying frame.

[0015] The preferred solution includes the following test methods: Take soil samples at different depths on site; Divide soil samples at different depths into multiple portions for flattening and compacting in various soil holding devices; The soil samples are spread flat in the soil container according to their depths. The soil samples with shallower depths are located at the higher end of the soil container, and the soil samples with deeper depths are located at the lower end of the soil container. A specimen block is placed in one of the soil containers and the pull rope and the slurry bottle are connected to the force sensor to conduct a sliding test. During the test, the pull-wire displacement sensor records the speed and displacement of the specimen block at different times, and matches the displacement pattern to the mounting frame, so that the subsequent linear drive cylinder pushes the mounting frame according to the displacement pattern, which is recorded as the basic displacement pattern. The remaining multiple test pieces are arranged side by side at the higher end of each soil containing device, and slurries with different drag reducing materials but the same content are poured into each slurry bottle; Each specimen block is subjected to a group control sliding test, and each force sensor records the tension and pressure of each flexible tube. When the carrier initially moves in the basic displacement mode, the carrier speed is adjusted in real time so that the carrier is at the midpoint between the fastest specimen block and the slowest specimen block; In a single test, select the fastest sliding specimen to determine the material with the best drag reduction; Pour slurry containing the drag-reducing material of different concentrations into each slurry bottle, conduct a comparative sliding test again, select the test piece that slides the fastest, and determine the most appropriate slurry concentration.

[0016] The beneficial effects of the present invention are as follows: constructing a test system that approximates on-site working conditions can assist in determining and selecting the drag reducing material with the best drag reducing performance; using multiple test channels, a variety of different materials can be tested at the same time, thereby improving test efficiency; the test channels can be arranged at an angle, and the drag reducing characteristics of drag reducing material slurries of different concentrations can be tested, which is close to actual use conditions and makes simulation tests more accurate; the soil holding device can lay soil samples of different depths along the length direction, thereby making the simulation test closer to reality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 It is a schematic diagram of the friction coefficient test system.

[0019] Figure 2 It is a partial structural detail diagram of the friction coefficient test system.

[0020] Figure 3 It is a schematic diagram of the sliding structure of the friction coefficient testing system.

[0021] Figure 4 It is a schematic diagram of the sinking working condition of the caisson of the present invention.

[0022] Figure 5 It is a schematic diagram of the material and slurry selection test system.

[0023] Figure 6 This is a detailed diagram of some of the structures of the test system.

[0024] Figure 7 This is a detailed picture of the pulp outlet structure.

[0025] Figure 8 is a schematic diagram of the bottom of the specimen block.

[0026] Fig. 9 This is a structural diagram of the trough platform and the mounting frame.

[0027] Fig.10 This is the structural diagram of the trough platform.

[0028] Fig.11 It is a schematic diagram of the soil holding device.

[0029] Fig.12 It is a schematic diagram of the contact foot.

[0030] In the figure: specimen block 1; slurry inlet hole 101; branch channel 102; slurry outlet hole 103; counterweight block 104; force sensor 2; pipe clamp 201; pull rope 3; fixed pulley 301; weighing device 4; first guide rail 5; data analyzer 6; soil holding device 7; soil sample 701; flange 702; splicing block 703; raised baffle 704; drag reduction material 8; test platform 9; front support 901; rear support 902; telescopic rod 903; second hinged seat 904; buckle 10; mobile platform 11; Groove platform 12; linear groove 1201; first hinged seat 1202; second guide rail 1203; collecting bucket 1204; slurry outlet 1205; slurry bottle 13; flexible tube 14; mounting frame 15; third guide rail 1501; slide bar 1502; contact foot 1503; friction strip 1504; first spring 1505; second spring 1506; top screw 1507; stop nut 1508; linear drive cylinder 16; traction block 17; wire-type displacement sensor 18; spring balancer 19. DETAILED DESCRIPTION

[0031] Embodiment 1: like Figure 1-3 , a friction coefficient testing system for drag reduction materials, shows the overall structure of the device and the back structure of the soil holding device, wherein the soil holding device 7 is a structure with an open top, and the side guard plates of the soil holding device 7 are fixed by buckles 10. When the soil test in the box is completed, the side plates of the soil holding device 7 can be removed by opening the buckles 10 to facilitate soil cleaning. Figure 1The overall structure diagram of the device is shown in FIG. 1 , on which a specimen block 1, a force sensor 2, a pull rope 3, a weighing device 4, a first guide rail 5, and a data analyzer 6 are arranged. The specimen block 1 is placed on the test platform to increase or decrease the specimen block 1 according to the simulated different confining pressure conditions. The force sensor 2 is connected to the mobile platform 11 as a whole and can reciprocate in one direction through the first guide rail 5. One end of the pull rope 3 is connected to the force sensor 2 and the other end bypasses the specimen block and connects to the force sensor 2. The weighing device 4 is placed on the test platform to calculate the weight of the specimen block 1. The data analyzer 6 is connected to the force sensor 2 through a data line and can calculate the friction coefficient of the drag reduction material according to the test data. The friction coefficient of different types of drag reduction materials can be measured through the combined action of the above devices. Finally, the above purpose is achieved.

[0032] Figure 3 The upper structure of the test platform and the detailed layout of the guide rail structure of the device are shown, in which the first guide rail 5 is placed in the center of the operating test platform, the mobile platform 11 is buckled on the upper part of the first guide rail 5 through the guide wheel, the force sensor 2 is connected to the mobile platform 11 as a whole, and can move left and right in a single direction under the action of the mobile platform, and the data analyzer 6 is placed on the operating test platform. When the test starts, the data analyzer 6 is connected to the force sensor 2 through the data line. The data analyzer mainly uses f 摩擦力 =μN can reflect the tensile force value of the test block from static to moving state in real time, and obtain the friction coefficient value through conversion. 摩擦力 That is, the value displayed by the force sensor. N is the weight of the specimen block measured by the weighing device and divided by the contact area of ​​the specimen block to obtain the positive pressure. μ is the friction coefficient. The data analyzer performs value conversion and organizes the data in the form of a line graph.

[0033] The above structural combination can measure the friction coefficient of different types of drag reducing materials, and can also simulate the friction coefficient of drag reducing materials under different confining pressure conditions, ultimately achieving the above purpose.

[0034] The test personnel install the device in place according to the design position. After the functions of the test device are correct, the test can be carried out. First, the test personnel compact the soil sample in layers and place it in the soil storage device 7, then weigh the test piece 1 to obtain data and input it into the data analyzer 6, then place the force sensor 2 on the first guide rail 5 close to one end of the soil storage device 7, and then brush the drag reduction material 8 to be tested on the soil to ensure that the surface of the drag reduction material is flat, then place the test piece 1 above the drag reduction material, connect one end of the pull rope 3 to the end of the force sensor 2, and the other end around the test piece 1 to connect to the end of the force sensor 2, and ensure that the connection point of the pull rope 3 and the end of the force sensor 2 are on the same plane. At this point, the entire test device is adjusted in place, and then the mobile platform 11 is operated to drive the force sensor 2 to move in a single direction above the guide rail 5. At this time, the pull rope 3 at the end of the force sensor 2 drives the test piece 1 from a static state to a sliding state, and the data displayed by the force sensor 2 is transmitted to the data analyzer in real time, and the friction coefficient of the drag reduction material can be quickly calculated. After a set of data tests are completed, the drag reduction material on the soil can be removed by shoveling and reapplied with new drag reduction material to repeat the above steps to obtain the friction coefficient of different drag reduction materials. When the overall test is completed, the tester opens the buckle 10 and removes the side plate of the soil holding device 7 to easily withdraw the internal soil. At this point, the entire test is complete.

[0035] The device can quickly and accurately measure the friction coefficient of different types of drag reducing materials through a mobile platform with a force sensor connected to a pull rope to drive the test block through a force sensor. The drag reducing characteristics of the drag reducing material can be tested under different confining pressure conditions by increasing or decreasing the number of test blocks in the soil holding device of the device. The soil in the soil holding device of the device is convenient for loading and unloading, and it is also convenient to replace the drag reducing material to be tested without affecting the test process. The device is an indoor measuring device for quickly testing the friction coefficient of drag reducing materials. The device is not only easy to operate, safe to use, and fully functional, but more importantly, the device is very convenient to assemble and debug. Therefore, the device has great practical value in testing the friction coefficient of drag reducing materials.

[0036] Embodiment 2: like Figure 5-12 A caisson drag reduction material testing system includes a test platform 9, on which is provided a soil container 7 for placing a soil sample 701, a test block 1 that can be moved against the soil sample 701, and a drag reduction material 8 for being arranged at the contact surface between the test block 1 and the soil sample 701.

[0037] The material of the contact surface between the specimen block 1 and the soil sample 701 is the same as that of the caisson.

[0038] In the preferred solution, a first guide rail 5 is provided on one side of the soil containing device 7 on the test platform 9, a mobile platform 11 is provided on the first guide rail 5, a force sensor 2 is provided on the mobile platform 11, a pull rope 3 is provided at one end of the force sensor 2, and one end of the pull rope 3 is connected to the specimen block 1.

[0039] In a preferred solution, an inclined groove platform 12 is provided on the test platform 9, and a plurality of separated linear grooves 1201 are provided in the groove platform 12. A soil containing device 7 is provided in each linear groove 1201, and the lower end of the soil containing device 7 is open.

[0040] The plurality of linear grooves 1201 make it possible to test the performance of a plurality of drag reducing materials 8 simultaneously in one test.

[0041] In addition to meeting the test of testing the friction coefficient by horizontal pulling, the inclined soil holding device 7 can also meet the test that is closer to the sinking condition of the caisson, that is: the drag reducing material 8 is prepared into slurries of different concentrations, and when each test block 1 slides down in the soil holding device 7 of each linear groove 1201, each slurry is poured from the higher end of the soil holding device 7, so that the actual drag reducing performance of drag reducing materials 8 of different concentrations can be tested in one experiment.

[0042] In the preferred scheme, a slurry inlet hole 101 is provided at the upper end of the specimen block 1, and a branch channel 102 connected to the slurry inlet hole 101 is provided in the slurry inlet hole 101. A plurality of slurry outlet holes 103 are provided on the contact surface between the specimen block 1 and the soil sample 701, and each slurry outlet hole 103 is connected to the branch channel 102. A carrying frame 15 that can move along the length direction of the straight groove 1201 is also provided on the groove platform 12. A plurality of slurry bottles 13 are provided on the carrying frame 15, and a flexible tube 14 is also provided. The lower end of the slurry bottle 13 is connected to the slurry inlet hole 101 through the flexible tube 14.

[0043] The carrying frame 15 and the specimen block 1 move in the same direction, but they move independently and are connected by a flexible tube 14. The flexible tube 14 is a spiral structure, which can allow the distance difference between the specimen block 1 and the slurry bottle 13 caused by the differential speed, thereby reducing the interference of the tension of the flexible tube 14 on the test.

[0044] A vent valve can be provided at the upper end of the slurry bottle 13. After opening, since the slurry bottle 13 is above the specimen block 1, the slurry inside enters the slurry inlet hole 101 along the flexible tube 14 under the action of gravity, and is distributed to each slurry outlet hole 103 and flows out to the surface of the soil sample 701. Compared with directly pouring the slurry on the surface of the soil sample 701, this method can save a lot of drag reduction materials 8 and has lower costs. In addition, since the outer wall of the caisson is also arranged with a slurry outlet pipe, when sinking, the slurry with the drag reduction material 8 is sprayed onto the soil wall. This method is more in line with actual working conditions and the test results are more accurate.

[0045] In the preferred solution, a plurality of force sensors 2 are provided on one side of the mounting frame 15 close to the flexible tube 14, and a tube clamping frame 201 is provided at one end of each force sensor 2. Each tube clamping frame 201 is sleeved on the upper end of each flexible tube 14, and a linear drive cylinder 16 is provided on one side of the groove platform 12. The cylinder rod end of the linear drive cylinder 16 is connected to the mounting frame 15.

[0046] The linear drive cylinder 16 adopts a servo electric cylinder, which can control the speed of the carrier 15 in each period. During the test, according to the tension value fed back by each force sensor 2, the speed of the carrier 15 can be changed, and the position of the specimen block 1 can be adjusted in time, so that the position of the carrier 15 is always at the midpoint of the fastest sliding specimen block 1 and the slowest sliding specimen block 1, ensuring that the tension caused by the stretching of the flexible tube 14 has the smallest overall impact on each specimen block 1.

[0047] In the preferred solution, a fixed pulley 301 is provided at the lower end of the groove platform 12, and a pull rope 3 is also provided. The pull rope 3 passes around the fixed pulley 301, a traction block 17 is provided at one end of the pull rope 3, and the other end of the pull rope 3 is connected to the front end of the specimen block 1. A pull-wire displacement sensor 18 is provided at the higher end of the groove platform 12, and the pull wire of the pull-wire displacement sensor 18 is connected to the rear end of the specimen block 1.

[0048] The upper end of the test piece block 1 is provided with a positioning groove, which can be used to place the counterweight block 104 of different weights of the test piece block 1. The end of the pull rope 3 is provided with a hook, which can be hung with a traction block 17 of different weights.

[0049] When the inclination angle of the channel platform 12 is small, the specimen block 1 may be difficult to slide due to excessive friction. Therefore, a pulley system and a pull rope 3 with a counterweight are used at the front end as a constant traction source. The weight of the specimen block 1 and the traction block 17 can be changed to make the sliding speed of the specimen block 1 moderate and easy to detect.

[0050] In the preferred embodiment, a first hinge seat 1202 and a second guide rail 1203 are provided at the lower end of the groove platform 12, a front support 901 and a rear support 902 are provided on the test platform 9, the front support 901 is hinged at the first hinge seat 1202, a telescopic rod 903 is provided in the rear support 902, a second hinge seat 904 is provided at the upper end of the telescopic rod 903, the second hinge seat 904 is slidably connected to the second guide rail 1203, and a spring balancer 19 is also provided on the groove platform 12, which pulls the rear end of the specimen block 1.

[0051] In order to simulate the effect of slurry outflow speed on the sinking of the caisson, the large inclination angle of the channel platform 12 can be appropriately adjusted, and the nut on the outer wall rear locking telescopic rod 903 can be adjusted to fix the height of the rear end of the channel platform 12. The spring balancer 19 is used to offset part of the downward force of the specimen block 1 to prevent the specimen block 1 from sliding down too fast.

[0052] In the preferred embodiment, the soil holding device 7 is a U-shaped structure, and outward flanges 702 are provided on both sides of the open end of the U-shaped structure, and multiple flanges 702 are arranged at intervals. Multiple splicing blocks 703 are provided at the bottom end of the soil holding device 7, and the splicing blocks 703 are provided with staggered raised baffles 704.

[0053] The soil storage device 7 adopts a bending process, and the splicing blocks 703 are spliced ​​end to end after processing and installed in the U-shaped structure of the soil storage device 7. The flanges 702 on both sides of the U-shaped structure are arranged in a staggered manner, so that each soil storage device 7 can be installed side by side on the vertical partition of the linear groove 1201.

[0054] The raised baffles 704 can prevent the soil sample from sliding downward. The raised baffles 704 are arranged in a staggered manner to form a zigzag flow channel. After the soil sample 701 is laid, the slurry can eventually flow out through the zigzag flow channel after participating in the test. The slurry mixed with soil particles gathers at the collection bucket 1204 and is discharged through the slurry outlet 1205 at the lowest end through a pipeline connection.

[0055] In the preferred scheme, a third guide rail 1501 is provided at both ends of the groove platform 12, and both ends of the carrying frame 15 are slidably connected to the third guide rail 1501. A slidable slide rod 1502 is provided at both ends of the carrying frame 15, and a threaded contact foot 1503 is provided at one end of the slide rod 1502. Friction strips 1504 are provided at both ends of the groove platform 12, and the contact foot 1503 slides against the friction strip 1504. A stop nut 1508 is provided at the end of the slide rod 1502 away from the groove platform 12, a first spring 1505 is provided between the contact foot 1503 and the carrying frame 15, and a second spring 1506 is provided between the stop nut 1508 and the carrying frame 15.

[0056] If a temporary test is conducted at the construction site or in a powerless condition, a non-slurry sliding test can be conducted using one of the linear slots 1201. At this time, the extension of the contact foot 1503 is adjusted, and the original compression of the second spring 1506 and the top screw 1507 is adjusted to change the contact pressure between the contact foot 1503 and the friction strip 1504, until the speed of the carrier 15 sliding down by gravity is slightly faster than the sliding speed of the non-slurry test specimen block 1. When the sliding test with slurry is conducted again, the carrier 15 can ensure that the sliding speed is close to that of each specimen block 1.

[0057] The preferred solution includes the following test methods: Take soil samples 701 at different depths on site; Divide soil samples 701 of different depths into multiple portions for paving and compacting in each soil storage device 7; The soil samples 701 are spread flat in the soil container 7 according to the depth, the soil samples 701 with a shallower depth are located at the higher end of the soil container 7, and the soil samples 701 with a deeper depth are located at the lower end of the soil container 7; A specimen block 1 is placed in one of the soil containers 7 and the pull rope 3 and the slurry bottle 13 are connected to the force sensor 2 to perform a sliding test. During the test, the pull-wire displacement sensor 18 records the speed and displacement of the specimen block 1 at different times, and matches the displacement pattern to the mounting frame 15, so that the subsequent linear drive cylinder 16 pushes the mounting frame 15 according to the displacement pattern, which is recorded as the basic displacement pattern. The remaining plurality of test pieces 1 are arranged side by side at the higher end of each soil container 7, and slurries of different drag reducing materials 8 but with the same content are poured into each slurry bottle 13; Each specimen block 1 is subjected to a group control sliding test, each force sensor 2 records the tension and pressure of each flexible tube 14, and when the carrier 15 initially moves in the basic displacement mode, the speed of the carrier 15 is adjusted in real time so that the carrier 15 is at the midpoint between the fastest specimen block 1 and the slowest specimen block 1; In a single test, select the specimen block 1 that slides the fastest and determine the material with the best drag reduction; Slurries with the drag-reducing material of different concentrations are poured into each slurry bottle 13, and a comparative sliding test is conducted again to select the test piece 1 that slides the fastest and determine the most appropriate slurry concentration.

[0058] After selecting the most suitable material and based on the most suitable material, the inclination angle of the channel platform 12 can be adjusted to change the slurry outflow and simulate the slurry outflow rate during the actual caisson sinking. After multiple inclination adjustment tests, the most suitable slurry outflow rate is selected.

[0059] Embodiment 3: like Figure 4 After the friction coefficient test of the mud drag reduction material is completed, the drag reduction material with excellent performance is selected and mixed with the mud as the drag reduction mud for the caisson sinking construction. The drag reduction mud is injected into the gap between the outer wall of the caisson and the soil through the grouting machine along the grouting pipeline 12. The friction between the caisson wall and the soil is reduced by the characteristics of the drag reduction material, thereby assisting the sinking of the caisson. During the sinking of the caisson, the sinking posture of the caisson is monitored by measurement. When the caisson has a posture deviation, the grouting amount is controlled by controlling the grouting pressure to appropriately correct the caisson. Finally, when the caisson sinks into place and the bottom plate is completed, the plugging bolts at the bottom end of the inner wall of the caisson are opened, and the drag reduction material outside the wall is discharged through the slurry discharge channel 13 (the slurry discharge channel is prefabricated during the manufacture of the caisson), and finally cement mortar is injected into the gap for reinforcement.

[0060] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A caisson drag reduction material testing system, characterized by: The test platform (9) comprises a soil holding device (7) provided on the test platform (9), the soil holding device (7) being used to place a soil sample (701), a test piece block (1) being movable against the soil sample (701), and a drag reducing material (8) being provided, the drag reducing material (8) being used to be arranged at the contact surface between the test piece block (1) and the soil sample (701).

2. The caisson drag reduction material testing system according to claim 1 is characterized by: A first guide rail (5) is provided on one side of the soil holding device (7) on the test platform (9), a mobile platform (11) is provided on the first guide rail (5), a force sensor (2) is provided on the mobile platform (11), a pull rope (3) is provided at one end of the force sensor (2), and one end of the pull rope (3) is connected to the test piece block (1).

3. The caisson drag reduction material testing system and testing method according to claim 1 is characterized by: An inclined slot platform (12) is provided on the test platform (9), a plurality of separated linear slots (1201) are provided in the slot platform (12), a soil containing device (7) is provided in each linear slot (1201), and the lower end of the soil containing device (7) is open.

4. The caisson drag reduction material testing system according to claim 3 is characterized by: A slurry inlet hole (101) is provided at the upper end of the specimen block (1), a branch flow channel (102) connected to the slurry inlet hole (101) is provided in the slurry inlet hole (101), a plurality of slurry outlet holes (103) are provided on the contact surface between the specimen block (1) and the soil sample (701), each slurry outlet hole (103) is connected to the branch flow channel (102), a carrying frame (15) movable along the length direction of the linear groove (1201) is further provided on the groove platform (12), a plurality of slurry bottles (13) are provided on the carrying frame (15), and a flexible tube (14) is also provided, and the lower ends of the slurry bottles (13) are connected to the slurry inlet hole (101) through the flexible tube (14).

5. The caisson drag reduction material testing system according to claim 4 is characterized in that: A plurality of force sensors (2) are provided on one side of the mounting frame (15) close to the flexible tube (14); a tube clamping frame (201) is provided at one end of each force sensor (2); each tube clamping frame (201) is sleeved onto the upper end of each flexible tube (14); a linear drive cylinder (16) is provided on one side of the channel platform (12); and a cylinder rod end of the linear drive cylinder (16) is connected to the mounting frame (15).

6. The caisson drag reduction material testing system according to claim 3 is characterized by: A fixed pulley (301) is provided at the lower end of the channel platform (12), and a pull rope (3) is also provided. The pull rope (3) passes around the fixed pulley (301), a traction block (17) is provided at one end of the pull rope (3), and the other end of the pull rope (3) is connected to the front end of the specimen block (1). A pull wire type displacement sensor (18) is provided at the higher end of the channel platform (12), and the pull wire of the pull wire type displacement sensor (18) is connected to the rear end of the specimen block (1).

7. The caisson drag reduction material testing system according to claim 6 is characterized by: A first hinge seat (1202) and a second guide rail (1203) are provided at the lower end of the channel platform (12); a front support seat (901) and a rear support seat (902) are provided on the test platform (9); the front support seat (901) is hinged to the first hinge seat (1202); a telescopic rod (903) is provided in the rear support seat (902); a second hinge seat (904) is provided at the upper end of the telescopic rod (903); the second hinge seat (904) is slidably connected to the second guide rail (1203); a spring balancer (19) is further provided on the channel platform (12); the spring balancer (19) holds the rear end of the test piece block (1).

8. The caisson drag reduction material testing system according to claim 3 is characterized by: The soil holding device (7) is a U-shaped structure, with outward flanges (702) provided on both sides of the open end of the U-shaped structure, and a plurality of flanges (702) arranged at intervals. A plurality of splicing blocks (703) are provided at the inner bottom end of the soil holding device (7), and the splicing blocks (703) are provided with staggered raised baffles (704).

9. The caisson drag reduction material testing system according to claim 4 is characterized by: A third guide rail (1501) is provided at both ends of the channel platform (12), and both ends of the carrying frame (15) are slidably connected to the third guide rail (1501). A slidable slide bar (1502) is provided at both ends of the carrying frame (15), and a contact foot (1503) connected by a thread is provided at one end of the slide bar (1502). A friction strip (1504) is provided at both ends of the channel platform (12), and the contact foot (1503) slides against the friction strip (1504). A stop nut (1508) is provided at one end of the slide bar (1502) away from the channel platform (12), a first spring (1505) is provided between the contact foot (1503) and the carrying frame (15), and a second spring (1506) is provided between the stop nut (1508) and the carrying frame (15).

10. The testing method of the caisson drag reduction material testing system according to claim 5 is characterized by: Take soil samples at different depths on site (701); Dividing soil samples (701) of different depths into multiple portions for flattening and compacting in each soil storage device (7); The soil samples (701) are spread flat in the soil containing device (7) according to the depth, wherein the soil samples (701) with a shallower depth are located at a higher end of the soil containing device (7), and the soil samples (701) with a deeper depth are located at a lower end of the soil containing device (7); A test piece (1) is placed in one of the soil containers (7) and a pull rope (3) and a slurry bottle (13) are connected to a force sensor (2) to perform a sliding test. During the test, a pull-wire displacement sensor (18) records the speed and displacement of the test piece (1) at different times and matches the displacement pattern to the mounting frame (15), so that the subsequent linear drive cylinder (16) pushes the mounting frame (15) according to the displacement pattern, which is recorded as a basic displacement pattern. Arrange the remaining plurality of test pieces (1) side by side at the higher end of each soil container (7), and pour slurries of different drag reducing materials (8) but with the same content into each slurry bottle (13); Each specimen block (1) is subjected to a group control sliding test, each force sensor (2) records the tension and pressure of each flexible tube (14), and when the carrier (15) initially moves in a basic displacement mode, the speed of the carrier (15) is adjusted in real time so that the carrier (15) is at the midpoint between the fastest specimen block (1) and the slowest specimen block (1); In a single test, select the specimen block (1) that slides the fastest to determine the material with the best drag reduction; Slurries containing the drag-reducing material of different concentrations are poured into each slurry bottle (13), and a comparative sliding test is performed again. The test piece (1) that slides the fastest is selected to determine the most appropriate slurry concentration.

Images