A test system and test method for studying cement soil sedimentation effect

Abstract

The present invention provides a test system and test method for studying cement soil sedimentation effect, which are used to solve the problem of uneven strength distribution of pile body caused by cement sedimentation in pile body after high-pressure rotary jetting pile construction is completed in the prior art. The system comprises: a settlement column module, a high-pressure rotary jetting pile simulation construction module for simulating high-pressure rotary jetting pile construction, a cement soil mixture particle size detection module for detecting the particle size of characteristic cement soil particles in high-pressure rotary jetting piles, and a cement soil mixture sampling module for sampling strength test samples and cement content test samples. The present invention is used to study the settlement law of characteristic particles of cement soil mixture of high-pressure rotary jetting piles over time, the change law of cement content of cement soil mixtures of different depths over time, and the corresponding law of cement content and 28d age strength, so as to realize the prediction of pile quality of high-pressure rotary jetting piles with sedimentation effect under different construction parameters, and solve the problem of uneven strength distribution of pile body caused by cement sedimentation in pile body after high-pressure rotary jetting pile construction is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering, and in particular relates to a test system and a test method for studying cement soil sedimentation effect. Background Art

[0002] Due to the advantages of small construction area, small vibration and low noise, high-pressure jet grouting piles are widely used in foundation reinforcement of existing and new buildings, water-stop curtains for deep foundation pits, anti-seepage projects such as reservoir dams and river embankments, slope retaining or water retaining projects. During on-site construction, first drill a hole to a predetermined depth, lower the drill rod with a nozzle to the bottom of the hole, and then turn on the high-pressure pump to spray high-pressure cement slurry around through the nozzle. As the spraying process proceeds, the drill rod will rotate at a predetermined speed and slowly rise, so that the high-pressure liquid can be evenly sprayed on the surrounding soil layer. After the spraying is completed, the slurry and soil mixture begins to solidify, and after a period of time, a circular or elliptical reinforcement body will be formed, which is the high-pressure jet grouting pile. After the jet grouting pile is completed, due to the uneven size of the soil particles wrapped by cement, large particles of cement soil will settle downward before the cement soil is initially set. The cement precipitation in the pile body can easily lead to uneven distribution of pile body strength. The lower part of the high-pressure jet grouting pile body has high strength, while the pile body strength in the top (generally 0~3m) is low. When the pile body is cored, the strength often fails to meet the design requirements. The problem of low pile body strength in the top range can be solved by improving the construction parameters, which requires the design of a test system to carry out indoor tests and determine the construction parameters.

[0003] At present, there are few studies on the sedimentation effect of cement-soil mixture of high-pressure rotary jet grouting piles at home and abroad. Similar studies are mainly concentrated in the field of dredging. By conducting sediment sedimentation column simulation tests, the sediment sedimentation process is effectively simulated, the formation and dissipation of excess pore water pressure inside the sediment, the development and changes of deposited sediment density and the settlement deformation law are monitored, and the main controlling factors affecting sedimentation are obtained.

[0004] Prior to the present invention, the invention patent (CN117783272A) disclosed a device and method for ultrasonically measuring the solid density distribution characteristics of a sedimentation column. A continuously sliding ultrasonic transducer is arranged on the outside of the cylindrical sedimentation column, and the density of the slurry at the measuring point is obtained according to the propagation speed of the ultrasonic wave in the liquid. This patent is an experimental device that can non-invasively and quickly analyze the vertical distribution characteristics of solid concentration. The ultrasonic transducer is installed on a highly controllable screw slider, which can realize the rapid acquisition of slurry concentration characteristics at different positions. However, since the maximum mud density that can be detected by this type of equipment at home and abroad is 1.4g / cm3, the detection capability is lower than the density of the cement-soil mixture of high-pressure rotary jet piles (>1.6g / cm3), so this method cannot solve the test of the cement-soil density of high-pressure rotary jet piles.

[0005] The invention patent (CN107421860A) discloses a one-dimensional vertical fill particle concentration test device and test method. The X-ray detection device is used to scan from top to bottom at regular intervals. The X-ray intensity change received by the X-ray receiving device is compared with the calibration sample to obtain the concentration distribution at each height. The mud density detection range of this patent is 1.0~3.0g / cm3, which can cover the density of high-pressure rotary jet pile cement soil mixture. However, due to the difference in the size of the soil particles wrapped in cement, the sediment density measured by this method still has an error that cannot be ignored.

[0006] To sum up, the problem to be solved in this application is to adopt reasonable testing methods to determine the change law of particle settlement of cement-soil mixture of high-pressure rotary jet grouting piles, and to establish the corresponding relationship between the cement content in the top range of the pile body and the age strength of the pile body, so as to achieve accurate prediction of the pile strength of the high-pressure rotary jet grouting pile body due to the sedimentation effect. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a test system and test method for studying the cement soil precipitation effect, which is used to solve the problem of uneven strength distribution of the pile body due to cement precipitation in the pile body after the construction of high-pressure rotary jet piles in the prior art is completed.

[0008] To achieve the above-mentioned and other related purposes, the present invention provides a test system for studying the cement soil sedimentation effect, comprising:

[0009] A sedimentation column module, the sedimentation column module comprising a base and an organic glass cylinder arranged above the base;

[0010] A high-pressure jet grouting pile simulation construction module, wherein the high-pressure jet grouting pile simulation construction module is used to make high-pressure jet grouting piles in the organic glass cylinder;

[0011] A particle size detection module for a cement-soil mixture, the particle size detection module for the cement-soil mixture comprising a ball slide rail vertically and fixedly arranged outside the organic glass tube, a laser particle size scanner mounted on the ball slide rail through a bracket, and a linear drive member, wherein the laser particle size scanner is driven by the linear drive member to move on the ball slide rail;

[0012] A cement-soil mixture sampling module, the cement-soil mixture sampling module comprising a plurality of sampling valves, a plurality of connecting pipes, a plurality of standard sample cylinders and a plurality of sampling tubes, the sampling valves and the connecting pipes being equal in number and connected one-to-one, the plurality of connecting pipes being arranged at equal intervals along the axial direction of the side wall of the organic glass cylinder, the plurality of standard sample cylinders being respectively connected to the plurality of connecting pipes when sampling a strength test sample, and the cement-soil mixture in the organic glass cylinder being flowed into and filled with the standard sample cylinder by opening the plurality of sampling valves when sampling a cement content test, and the plurality of sampling tubes being respectively extended into the organic glass cylinder for sampling by opening the plurality of sampling valves.

[0013] Optionally, the settlement column module also includes an overflow trough arranged at the top of the plexiglass tube and a return slurry collection tube for collecting excess cement-soil mixture slurry. The overflow trough transports the cement-soil mixture slurry overflowing from the top of the plexiglass tube during the construction of the high-pressure rotary jet pile simulation construction module to the return slurry collection tube through a return slurry pipe.

[0014] Optionally, the high-pressure jet grouting pile simulation construction module includes a guide rail vertical connecting rod fixedly connected above the base, a connecting piece slidingly matched with the guide rail vertical connecting rod, an auger rod rotatably arranged on the connecting piece, a nozzle fixedly connected to the bottom end of the auger rod, a slurry supply and delivery part, an air supply and delivery part, a cement slurry supply part, a drill rod power part driving the auger rod to rotate, and a linear power part driving the connecting piece to move up and down along the guide rail vertical connecting rod;

[0015] One end of the slurry supply and delivery part and the air supply and delivery part both pass through the connecting piece and enter the auger rod to be connected to the nozzle, and the other ends of the slurry supply and delivery part and the air supply and delivery part are respectively connected to the cement slurry supply part and the air compressor, and a cement slurry pump is provided between the slurry supply and delivery part and the cement slurry supply part;

[0016] The cement slurry supply part is used for providing cement slurry with a designed water-cement ratio for the test.

[0017] Optionally, the slurry supply and conveying part has the same structure as the air supply and conveying part, and the slurry supply and conveying part comprises a first L-shaped tube, a spiral tube, and a second L-shaped tube, and both ends of the spiral tube are fixedly connected to one end of the first L-shaped tube and one end of the second L-shaped tube respectively;

[0018] The other end of the first L-shaped tube of the slurry supply and transportation part is connected to the cement slurry supply part through the cement slurry pump, and the other end of the first L-shaped tube of the air supply and transportation part is connected to the air compressor;

[0019] The second L-shaped tube of the slurry supply and conveying part and the second L-shaped tube of the air supply and conveying part both pass through the connecting piece, enter the auger rod and are connected to the nozzle.

[0020] Optionally, the cement slurry supply part includes a production tank, a mixing shell fixedly connected to the top of the production tank, a raw material mixing mechanism arranged in the mixing shell, a rotating cylinder rotatably connected to the inner wall of the production tank, a cross fixedly connected to the inner wall of the rotating cylinder, a stirring column fixedly connected to the middle position of the cross, stirring blades, and a water spraying mechanism arranged below the rotating cylinder, the rotating cylinder has a plurality of upward-facing meshing teeth on the circumference of the top, the raw material mixing mechanism is transmission-connected to the meshing teeth on the rotating cylinder, there are a plurality of stirring blades, and the plurality of stirring blades are spaced apart along the axial and circumferential directions of the stirring column, the mixing shell has two feed inlets, and the production tank has a discharge port at the bottom.

[0021] Optionally, the raw material mixing mechanism includes two horizontal axes horizontally rotatably connected to the mixing shell, two crank cylinders respectively fixedly connected to the two horizontal axes, two connecting cylinders respectively communicated with the two crank cylinders, a mixing spherical cavity located between and connected to the two connecting cylinders, a hybrid power component driving the horizontal axes to rotate, two rotating disks and two transmission gears, the two transmission gears are respectively coaxially fixedly matched with the two horizontal axes, and are both engaged with the meshing teeth on the rotating cylinder for transmission, the two rotating disks are respectively coaxially fixedly matched with the two horizontal axes, each rotating disk is slidably matched with the bottom of the feed inlet located above, each rotating disk has a plurality of transfer channels circumferentially and toward its own axial direction on the side wall, each transfer channel is communicated with the crank cylinder, and the mixing spherical cavity has a plurality of leakage holes.

[0022] Optionally, the water spraying mechanism includes an annular tube fixedly connected to the inner wall of the production tank and located below the rotating cylinder, and a water spraying head. There are multiple water spraying heads, and the multiple water spraying heads are arranged on the annular tube at a first spacing, and the water spraying direction is toward the central axis of the stirring column. Each of the water spraying heads has a control valve.

[0023] Optionally, or, the cement-soil mixture particle size detection module includes a spiral rod vertically and rotatably arranged above the base, a motion block threadedly matched with the spiral rod, two sliding rails vertically arranged above the base, two sliding blocks respectively slidably matched with the two sliding rails, an arc-shaped rail, an arc-shaped internal gear block, a laser particle size scanner, an adjustment block, a motion power member driving the motion block to move up and down, and a rotating power component meshing with the arc-shaped internal gear block and driving the laser particle size scanner to move;

[0024] The spiral rod and the two sliding rails are arranged in a triangular structure, the arc-shaped inner gear blocks are fixedly connected to the moving block and the two sliding blocks, and the arc-shaped rails are arranged above the arc-shaped inner gear blocks;

[0025] There are two adjusting blocks, and the two adjusting blocks are fixedly connected to two ends of the arc-shaped inner gear block.

[0026] Optionally, the rotary power assembly includes a driving gear meshing with the arc-shaped inner gear block, a support, a roller rotatably arranged at the bottom of the support, and a rotary power member driving the driving gear to rotate, wherein the driving gear is rotatably arranged at the bottom of the support, and there are four rollers, two of which are located on the inner side of the arc-shaped rail, and the other two are located on the outer side of the arc-shaped rail;

[0027] The laser particle size scanner is installed on the support and faces the central axis direction of the organic glass cylinder.

[0028] A test method for a test system for studying cement-soil sedimentation effect, applicable to the test system for studying cement-soil sedimentation effect as described above, comprises the following steps:

[0029] Original soil sample acquisition: using a geological drill, drill on-site to obtain original soil samples, send them to the laboratory, fill them into the organic glass cylinder in layers of 50 cm and compact them, and finally fill the organic glass cylinder with original soil;

[0030] Drilling holes in the original soil: Use a Luoyang shovel to drill holes in the center of the original soil until the bottom of the original soil. The diameter of the drilling hole is 5 cm.

[0031] High-pressure jet grouting pile simulation construction: by starting the linear power part, the connecting part drives the auger rod to move vertically downward into the soil-taking hole in the organic glass tube, and slowly lowers it to the bottom of the hole, and then uses the cement slurry supply part to make the cement slurry required for the test, and then starts the cement slurry pump, the air compressor and the drill rod power part, and then starts the high-pressure jet grouting pile simulation construction according to the designed lifting speed and the rotation speed of the auger rod;

[0032] Detection of particle size of cement-soil mixture: After the high-pressure jet-jet pile simulation construction is completed, the laser particle size scanner is driven by the linear drive member to move downward from the top of the organic glass tube at a uniform speed of 4 m / min along the ball slide rail and scan the particle distribution of the test cement slurry mixture to generate a scanned image. After the laser particle size scanner moves to the bottom of the organic glass tube, it moves upward at 10 m / min and returns to the starting point. Then, according to the imaging results of the laser particle size scanner, the characteristic particles in the image are selected, and the bottom of the organic glass tube is taken as the coordinate zero point. The characteristic particle position changes with time curve is plotted, and the curve is derived to obtain the characteristic particle movement speed change curve with time. The curve is fitted to obtain the cement soil characteristic particle sedimentation rate equation;

[0033] Sampling for cement content test: After the high-pressure rotary jet pile simulation construction is completed, the plurality of sampling tubes are connected to the plurality of connecting tubes according to 0min, 5min, 10min, 30min, 1h, 2h, and 6h, and then the plurality of sampling valves are opened, and the plurality of sampling tubes are respectively extended into the organic glass cylinder to sample the cement-soil mixture, and the sampling mass of each time is 30g. Then the sampling tube is pulled out and the sampling valve is closed, and the sample is poured into a beaker, and the density of the sample is tested using a densitometer, and the cement content in the sample is tested using an improved EDTA titration test, and a density variation curve of the cement-soil mixed sample over time is plotted, and a cement content variation curve of the cement-soil mixed sample over time is plotted;

[0034] Sampling of strength test samples: After the simulation construction of high-pressure jet grouting piles is completed, the plurality of standard sample cylinders are respectively connected to the plurality of connecting pipes at 0min, 5min, 10min, 30min, 1h, 2h, and 6h. The cement-soil mixture in the organic glass cylinder is opened to flow into and fill the standard sample cylinder. The cylinder is sent to a standard curing box for curing for 48h and then demoulded to produce strength test samples. After the sample strength reaches the 28d-age strength, the sample strength is tested using a universal pressure testing machine.

[0035] Comprehensive analysis of test data: Comprehensive analysis of test data is conducted to determine the relationship between the strength of cement soil specimens and the cement content and density of the cement soil mixture, and to predict whether the strength of the pile top and pile body meets the requirements under the designed construction parameters.

[0036] As described above, the test system and test method for studying the cement soil sedimentation effect of the present invention have at least the following beneficial effects:

[0037] The high-pressure rotary jet pile simulation construction module is used to make high-pressure cement slurry into high-pressure rotary jet piles in the organic glass tube. After the construction is completed, the laser particle size scanner is driven by the linear drive component at a fixed time, and moves downward at a uniform speed along the ball slide from the top of the organic glass tube, and scans the particle distribution of the test cement slurry mixture to generate a scanned image. After the laser particle size scanner moves to the bottom of the organic glass tube, it moves upward and returns to the starting point. Then, according to the imaging results of the laser particle size scanner, the characteristic particles in the image are selected, and the bottom of the organic glass tube is taken as the coordinate zero point. The characteristic particle position changes with time curve is plotted, and the curve is derived to obtain the characteristic particle movement speed change with time curve. The curve is fitted to obtain the cement soil characteristic The characteristic particle sedimentation rate equation is used to determine the sedimentation law of characteristic particles; when sampling the strength test sample, multiple standard sample tubes are connected to multiple connecting pipes respectively, and multiple sampling valves are opened to allow the cement soil mixture in the organic glass tube to flow into and fill the standard sample tube, and the 28-day strength is tested after curing, and the strength test sample is demoulded to be made, and the sample strength is tested using a universal pressure testing machine. When sampling the cement content test, multiple sampling tubes are respectively extended into the organic glass tube by opening multiple sampling valves to take samples, and the EDTA titration test is used to determine the cement content in the sample, and the relationship curve between the sample cement content and the 28-day strength and the time-varying curve of the cement content at different depths are established. The present invention can be used to study the sedimentation law of characteristic particles of cement soil mixture of high-pressure rotary jet piles over time, the change law of cement content of cement soil mixtures at different depths over time, and the corresponding law of cement content and 28-day strength, and realizes the prediction of the quality of high-pressure rotary jet piles with sedimentation effect under different construction parameters, and helps solve the problem of uneven strength distribution of the pile body due to cement precipitation in the pile body after the construction of the high-pressure rotary jet pile is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Shown is a schematic diagram of the three-dimensional structure of the present invention;

[0039] Figure 2 Shown is a schematic diagram of the three-dimensional structure of the sedimentation column module of the present invention;

[0040] Figure 3 It is a schematic diagram of the three-dimensional structure of the settlement column module and the high-pressure jet grouting pile simulation construction module of the present invention;

[0041] Figure 4 Shown is a schematic diagram of the three-dimensional structure of a particle size detection module for a cement-soil mixture according to the present invention;

[0042] Figure 5 Shown is a schematic diagram of the three-dimensional structure of the cement-soil mixture sampling module of the present invention;

[0043] Figure 6 It is a schematic diagram of the three-dimensional structure of the slurry supply and conveying part of the present invention;

[0044] Figure 7 It is a schematic diagram of the three-dimensional structure of the cement slurry supply part of the present invention;

[0045] Figure 8 It is a schematic diagram of the internal three-dimensional structure of the cement slurry supply part of the present invention;

[0046] Fig. 9 It is a schematic diagram of the three-dimensional structure of another embodiment of the particle size detection module of the cement-soil mixture of the present invention;

[0047] Fig.10 It is an enlarged view of part A of the present invention.

[0048] Component number description

[0049] Settlement column module 1, cement-soil mixture particle size detection module 2, high-pressure rotary jet pile simulation construction module 3, cement-soil mixture sampling module 4, organic glass cylinder 5, overflow trough 6, return slurry pipe 7, return slurry collection cylinder 8, base 9, cement slurry supply unit 10, cement slurry pump 11, air compressor 12, slurry supply and transportation unit 13, air supply and transportation unit 14, drill pipe power unit 15, connector 16, spiral drill rod 17, nozzle 18, linear power unit 19, guide rail vertical connecting rod 20, original soil sample 21, ball slide rail 22, laser particle size scanner 23, sampling valve 24, connecting pipe 25, standard sample cylinder 26, sampling tube 27;

[0050] Production tank 101, mixing shell 102, mixing mechanism 103, horizontal shaft 1031, crank cylinder 1032, connecting cylinder 1033, mixing spherical cavity 1034, hybrid power element 1035, rotating disk 1036, transmission gear 1037, material transfer channel 1038, leakage hole 1039, rotating cylinder 104, cross 105, stirring column 106, stirring blade 107, annular tube 1081, water spray head 1082, meshing teeth 109, feeding port 1010, and discharging port 1011;

[0051] A first L-shaped tube 131, a spiral tube 132, and a second L-shaped tube 133;

[0052] Screw rod 2001, moving block 2002, sliding rail 2003, sliding block 2004, arc rail 2005, arc inner gear block 2006, adjustment block 2007, moving power part 2008, rotating power component 2009, driving gear 20091, support 20092, roller 20093, rotating power part 20094. DETAILED DESCRIPTION

[0053] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0054] See also Figures 1 to 10 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0055] The following embodiments are only for illustration purposes and can be combined with each other, and are not limited to the contents presented in the following single embodiments.

[0056] In this embodiment, please refer to Figures 1 to 10 The present invention provides a test system for studying the cement soil sedimentation effect, comprising:

[0057] A settlement column module 1, a high-pressure rotary jet pile simulation construction module 3, a cement-soil mixture particle size detection module 2 and a cement-soil mixture sampling module 4, wherein the settlement column module 1 comprises a base 9 and an organic glass tube 5 arranged above the base 9; the base 9 is used to support the test system, and the organic glass tube 5 can be made of methyl methacrylate, polymethyl methacrylate, polycarboxylic acid, inorganic glass, and glass masterbatch, so as to have excellent transparency, mechanical strength, weather resistance and other characteristics; the high-pressure rotary jet pile simulation construction module 3 is used to make high-pressure cement slurry into high-pressure rotary jet piles in the organic glass tube 5;

[0058] The cement-soil mixture particle size detection module 2 includes a ball slide rail 22 vertically and fixedly arranged on the outside of the organic glass tube 5, a laser particle size scanner 23 installed on the ball slide rail 22 through a bracket, and a linear drive component, wherein the linear drive component includes a hydraulic cylinder, a cylinder or an electric push rod, one end of the linear drive component is fixedly connected to the base 9, and the other end is fixedly connected to the bracket, and the laser particle size scanner 23 is driven by the linear drive component to move on the ball slide rail 22. The laser particle size scanner 23 is an efficient and accurate particle size testing tool, which is suitable for particle size analysis of various granular materials; the cement-soil mixture sampling module Block 4 includes a plurality of sampling valves 24, a plurality of connecting tubes 25, a plurality of standard sample tubes 26 and a plurality of sampling tubes 27. The number of the sampling valves 24 and the connecting tubes 25 are equal and they are connected one by one. The plurality of connecting tubes 25 are arranged at equal intervals along the axial direction of the side wall of the organic glass tube 5. When sampling the strength test samples, the plurality of standard sample tubes 26 are respectively connected to the plurality of connecting tubes 25, and the cement-soil mixture in the organic glass tube 5 is allowed to flow into and fill the standard sample tubes 26 by opening the plurality of sampling valves 24. When sampling the cement content test, the plurality of sampling valves 24 are opened to extend the plurality of sampling tubes 27 into the organic glass tube 5 for sampling.

[0059] The high-pressure rotary jet pile is made into a high-pressure rotary jet pile by the high-pressure rotary jet pile simulation construction module 3 in the organic glass tube 5. After the construction is completed, the laser particle size scanner 23 is driven by the linear drive member at a fixed time, and moves downward at a uniform speed along the ball slide rail 22 from the top of the organic glass tube 5, and scans the particle distribution of the test cement slurry mixture to generate a scanned image. After the laser particle size scanner 23 moves to the bottom of the organic glass tube 5, it moves upward and returns to the starting point. Then, according to the imaging result of the laser particle size scanner 23, the characteristic particles in the image are selected, and the bottom of the organic glass tube 5 is taken as the coordinate zero point. The characteristic particle position changes with time curve is plotted, and the curve is derived to obtain the characteristic particle movement speed change with time curve. The curve is fitted to obtain the cement soil characteristic particle. The characteristic particle sedimentation rate equation is used to determine the sedimentation law of characteristic particles; when sampling the strength test samples, multiple standard sample tubes 26 are connected to multiple connecting pipes 25 respectively, and multiple sampling valves 24 are opened to allow the cement-soil mixture in the organic glass tube 5 to flow into and fill the standard sample tube 26. After curing, the 28-day strength is tested, and the strength test samples are demoulded to make strength test samples. The sample strength is tested using a universal pressure testing machine. When sampling the cement content test, multiple sampling valves 24 are opened at regular intervals to extend multiple sampling tubes 27 into the organic glass tube 5 to take samples, and an EDTA titration test is used to determine the cement content in the sample, and a relationship curve between the sample cement content and the 28-day strength and a curve of cement content change with time at different depths are established. The present invention can be used to study the settlement law of characteristic particles of cement-soil mixture of high-pressure jet grouting piles over time, the change law of cement content of cement-soil mixtures of different depths over time, and the correspondence law between cement content and strength at 28 days of age. It realizes the prediction of pile quality of high-pressure jet grouting piles with sedimentation effect under different construction parameters, and helps to solve the problem of uneven strength distribution of the pile body due to cement sedimentation in the pile body after the construction of the high-pressure jet grouting piles is completed.

[0060] In this embodiment, please refer to Figure 2 The settlement column module 1 also includes an overflow trough 6 arranged at the top of the organic glass tube 5 and a return slurry collection tube 8 for collecting excess cement-soil mixture slurry. The overflow trough 6 transports the cement-soil mixture slurry overflowing from the top of the organic glass tube 5 during the construction of the high-pressure rotary jet pile simulation construction module 3 to the return slurry collection tube 8 through the return slurry pipe 7. During the high-pressure rotary jet pile simulation construction process, the overflow trough 6 transports the cement-soil mixture slurry overflowing from the top of the organic glass tube 5 to the return slurry collection tube 8 through the return slurry pipe 7, thereby recovering the excess slurry, effectively collecting the overflowed cement-soil mixture slurry, and preventing it from flowing out of the experimental area to cause waste or pollution.

[0061] In this embodiment, please refer to Figure 3The high-pressure jet grouting pile simulation construction module includes a guide rail vertical connecting rod 20 fixedly connected to the top of the base 9, a connecting piece 16 slidingly matched with the guide rail vertical connecting rod 20, a spiral drill rod 17 rotatably arranged on the connecting piece 16, a nozzle 18 fixedly connected to the bottom end of the spiral drill rod 17, a slurry supply and conveying part 13, an air supply and conveying part 14, a cement slurry supply part 10, a drill rod power part 15 driving the spiral drill rod 17 to rotate, and a linear power part 19 driving the connecting piece 16 to move up and down along the guide rail vertical connecting rod 20 The drill rod power member 15 includes a motor, the end of the motor has a motor gear, the top of the auger rod 17 is provided with a motor pinion, the motor pinion is meshed with the motor pinion for transmission, so that when the drill rod power member 15 drives the motor gear to rotate, the motor pinion is driven to rotate, thereby driving the auger rod 17 to rotate, and the linear power member 19 includes a hydraulic cylinder, a pneumatic cylinder or an electric push rod, one end of the linear power member 19 is fixedly connected to the connecting member 16, and the other end is fixedly connected to the base 9;

[0062] One end of the slurry supply and conveying part 13 and the air supply and conveying part 14 pass through the connecting piece 16 and enter the auger rod 17 to be connected to the nozzle 18, and the other ends of the slurry supply and conveying part 13 and the air supply and conveying part 14 are respectively connected to the cement slurry supply part 10 and the air compressor 12, and a cement slurry pump 11 is provided between the slurry supply and conveying part 13 and the cement slurry supply part 10; the cement slurry supply part 10 is used to provide cement slurry with a designed water-cement ratio for the test.

[0063] During the simulation construction of high-pressure rotary jet piles, the cement slurry supply unit 10 provides the experiment with cement slurry with a designed water-cement ratio, so that researchers can flexibly adjust the water-cement ratio of the cement slurry according to different experimental purposes and requirements, thereby improving applicability and practicality. The cement slurry pump 11 is started to transport the cement slurry in the cement slurry supply unit 10 to the nozzle 18 through the slurry supply and conveying unit 13. At the same time, the gas of the air compressor 12 is transported to the nozzle 18 through the gas supply and conveying unit 14, thereby ensuring that the cement slurry and gas can be accurately and efficiently injected into the organic glass tube 5 to form high-quality rotary jet piles. Through the guide rail vertical connecting rod 20 and the connecting member 16 that slides with it, the drill rod power member 15 that drives the auger rod 17 to rotate, and the linear power member 19 that drives the connecting member 16 to move up and down along the guide rail vertical connecting rod 20, the vertical positions of the auger rod 17 and the nozzle 18 can be accurately controlled, and the vertical movement speed and rotation speed of the auger rod 17 can be conveniently adjusted, thereby also providing a possibility for studying the molding effect of high-pressure rotary jet piles with different construction speed combinations.

[0064] In this embodiment, please refer to Figure 6The slurry supply and delivery part 13 and the gas supply and delivery part 14 have the same structure. The slurry supply and delivery part 13 includes a first L-shaped tube 131, a spiral tube 132, and a second L-shaped tube 133. The two ends of the spiral tube 132 are fixedly connected with one end of the first L-shaped tube 131 and the second L-shaped tube 133 respectively; the first L-shaped tube 131 and the second L-shaped tube 133 are both made of hard materials, which is conducive to enhancing the overall structural strength of the entire slurry supply and delivery part 13 and the gas supply and delivery part 14. The spiral tube 132 has a certain elasticity and a certain hardness, so that it can meet the needs of up and down expansion and contraction during the construction of high-pressure jet grouting piles, and can also meet the needs of continuous and uniform supply of cement slurry or gas, thereby improving the stability of the conveying state;

[0065] The other end of the first L-shaped tube 131 of the slurry supply and transportation part 13 is connected to the cement slurry supply part 10 through the cement slurry pump 11, and the other end of the first L-shaped tube 131 of the air supply and transportation part 14 is connected to the air compressor 12;

[0066] The second L-shaped tube 133 of the slurry supply and conveying part 13 and the second L-shaped tube 133 of the air supply and conveying part 14 both pass through the connecting piece 16 and enter the auger rod 17 to be connected with the nozzle 18 .

[0067] During the construction of high-pressure rotary jet piles, the connecting piece 16 will move up and down along the guide rail vertical connecting rod 20, driving the connected spiral drill rod 17 and the nozzle 18 to move up and down. The spiral tube 132 in the slurry supply and delivery part 13 and the air supply and delivery part 14 has a certain elasticity and a certain hardness, so that it can expand and contract accordingly with the up and down movement of the connecting piece 16 and meet the continuous and uniform supply of cement slurry, thereby ensuring the distribution of cement slurry inside the pile body and the mixing effect with the soil.

[0068] In this embodiment, please refer to Figure 3 , Figure 7 and Figure 8 The cement slurry supply part 10 includes a production tank 101, a mixing shell 102 fixedly connected to the top of the production tank 101, a raw material mixing mechanism 103 arranged in the mixing shell 102, a rotating cylinder 104 rotatably connected to the inner wall of the production tank 101, a cross 105 fixedly connected to the inner wall of the rotating cylinder 104, a stirring column 106 fixedly connected to the middle position of the cross 105, a stirring blade 107, and a water spraying mechanism arranged below the rotating cylinder 104. The top of the rotating cylinder 104 has a plurality of meshing teeth 109 facing upward in the circumferential direction. The raw material mixing mechanism 103 is transmission-connected to the meshing teeth 109 on the rotating cylinder 104. There are a plurality of stirring blades 107, and the plurality of stirring blades 107 are spaced apart along the axial and circumferential directions of the stirring column 106. The mixing shell 102 has two feeding ports 1010, and the bottom of the production tank 101 has a discharge port 1011.

[0069] In the process of making cement slurry, the water spraying mechanism is connected to the external water source, the mixed raw materials required for the test are added into the two material ports, the raw material mixing mechanism 103 is started to mix the raw materials in the two feeding ports 1010 and then sprinkled into the production tank 101 in batches. At the same time, the water spraying mechanism is operated to spray water to the mixed raw materials falling downward to make the two contact each other. After the mixed raw materials are mixed with water, they are accelerated to fall into the production tank 101. The raw material mixing mechanism 103 is connected to the meshing teeth 109 on the rotating cylinder 104 to drive the rotating cylinder 104 to rotate, and then drive the stirring column 106 to rotate. Multiple stirring blades 107 are arranged at intervals in the axial and circumferential directions of the stirring column 106, which ensures that the cement slurry is stirred in all directions in the production tank 101, thereby improving the uniformity and mixing effect of the cement slurry. Finally, the cement slurry is discharged from the discharge port 1011 at the bottom of the production tank 101 and transported to the nozzle 18 position through the cement slurry pump 11 to complete the simulated construction of high-pressure rotary jet piles.

[0070] In this embodiment, please refer to Figure 8 The raw material mixing mechanism 103 includes two horizontal shafts 1031 horizontally rotatably connected to the mixing shell 102, two crank cylinders 1032 respectively fixedly connected to the two horizontal shafts 1031, two connecting cylinders 1033 respectively connected to the two crank cylinders 1032, a mixing ball cavity 1034 located between and connected to the two connecting cylinders 1033, a hybrid power component 1035 driving the horizontal shaft 1031 to rotate, two rotating discs 1036 and two transmission gears 1037, wherein the hybrid power component 1035 includes a motor, which provides a power source for the entire raw material mixing mechanism 103, and the two rotating discs 1036 and two transmission gears 1037. The transmission gears 1037 are coaxially fixedly matched with the two horizontal shafts 1031 respectively, and are meshed with the meshing teeth 109 on the rotating cylinder 104 for transmission. The two rotating discs 1036 are coaxially fixedly matched with the two horizontal shafts 1031 respectively. Each rotating disc 1036 is slidably matched with the bottom of the feed inlet 1010 located above. Each rotating disc 1036 has a plurality of transfer channels 1038 on the circumferential side wall and toward its own axial direction. Each transfer channel 1038 is connected to the crank cylinder 1032. The mixing sphere cavity 1034 has a plurality of leakage holes 1039.

[0071] The horizontal shaft 1031 is driven to rotate by the hybrid power component 1035, so that each transfer disk 1036 has a plurality of transfer channels 1038 on the circumferential side wall and toward its own axial direction, which can intermittently and effectively transfer the raw materials from the two feed ports 1010 to the crank cylinder 1032 respectively, and then transport the raw materials at both ends to the mixing sphere cavity 1034 through the two connecting cylinders 1033. While the mixing sphere cavity 1034 rotates, it can ensure that the raw materials are fully dispersed and evenly mixed during the mixing process, thereby improving the quality of the cement slurry, and then fall into the production tank 101 through the leakage hole 1039 on the mixing sphere cavity 1034.

[0072] In this embodiment, please refer to Figure 8 The water spraying mechanism includes an annular tube 1081 fixed to the inner wall of the production tank 101 and located below the rotating cylinder 104, and a water spraying head 1082. There are multiple water spraying heads 1082, and the multiple water spraying heads 1082 are arranged on the annular tube 1081 at a first spacing, and the water spraying direction is toward the central axis of the stirring column 106. Each of the water spraying heads 1082 has a control valve, and the control valve can accurately control the water spraying amount. Multiple control valves can be integrated into the control center for unified control, so as to facilitate management. The annular tube 1081 is fixed to the inner wall of the production tank 101 and is located below the rotating cylinder 104. Multiple water spraying heads 1082 are arranged on the annular tube 1081 at a first spacing, and the water spraying direction is toward the central axis of the stirring column 106, so that the water spraying covers a wider range, so that the mixed raw materials can be fully in contact with water.

[0073] In this embodiment, please refer to Fig. 9 and Fig.10, or, the cement-soil mixture particle size detection module 2 includes a screw rod 2001 vertically and rotatably arranged above the base 9, a moving block 2002 threadedly matched with the screw rod 2001, two sliding rails 2003 vertically arranged above the base 9, two sliding blocks 2004 respectively slidably matched with the two sliding rails 2003, an arc rail 2005, an arc-shaped internal gear block 2006, a laser particle size scanner 23, an adjustment block 2007, a moving power member 2008 driving the moving block 2002 to move up and down, and a rotating power component 2009 meshing with the arc-shaped internal gear block 2006 and driving the laser particle size scanner 23 to move; the moving power member 2008 includes a motor; the screw rod 2001 and the two sliding rails 2003 are arranged in a triangular structure, providing a stable supporting structure. The triangle has stability. When the moving block 2002 and the sliding block 2004 move along their respective tracks, the movement trajectory is guaranteed to be more accurate and the stability is improved. The arc-shaped internal gear block 2006 is fixedly connected to the moving block 2002 and the two sliding blocks 2004, and the arc-shaped rail 2005 is arranged above the arc-shaped internal gear block 2006; there are two adjusting blocks 2007, and the two adjusting blocks 2007 are fixedly connected to the two ends of the arc-shaped internal gear block 2006. The initial position, movement range, etc. of the laser particle size scanner 23 are limited and adjusted through the adjusting blocks 2007.

[0074] By providing a spiral rod 2001 and a moving power member 2008 for driving the moving block 2002 to move up and down, the laser particle size scanner 23 can be moved in the vertical direction. When detecting the particle size of cement-soil mixture particles, the mixture at different heights may have different particle distributions. The up and down movement allows the scanner to scan and detect the mixture at different height levels in the organic glass tube 5 one by one, and obtain accurate particle size data at each position from the bottom to the top. Through the cooperation of the arc track 2005, the arc inner gear block 2006 and the rotating power assembly 2009 meshing with the arc track 2005, the laser particle size scanner 23 can move along the arc track 2005. Combined with its up and down movement, the scanner can flexibly change its position in a three-dimensional space, and detect the cement-soil mixture from different angles.

[0075] In this embodiment, please refer to Fig.10The rotating power assembly 2009 includes a driving gear 20091 meshing with the arc-shaped inner gear block 2006, a support 20092, a roller 20093 rotatably arranged at the bottom of the support 20092, and a rotating power member 20094 driving the driving gear 20091 to rotate, wherein the rotating power member 20094 includes a motor, the driving gear 20091 is rotatably arranged at the bottom of the support 20092, and there are four rollers 20093, two of which are located on the inner side of the arc-shaped rail 2005, and the other two of which are located on the outer side of the arc-shaped rail 2005; the laser particle size scanner 23 is installed on the support 20092 and faces the central axis direction of the organic glass tube 5, which is conducive to comprehensive and effective detection of the cement-soil mixture in the organic glass tube 5.

[0076] When the driving gear 20091 is driven to rotate by the rotating power part 20094, the driving gear 20091 meshes with the arc-shaped inner gear block 2006 for transmission. Four rollers 20093 are arranged, two of which are located on the inner side of the arc-shaped rail 2005, and the other two are located on the outer side of the arc-shaped rail 2005, which can provide stable support for the support 20092 and the laser particle size scanner 23 installed on the support 20092. When the laser particle size scanner 23 makes an arc motion along the arc-shaped rail 2005, the roller 20093 can roll closely against the arc-shaped rail 2005. Through the joint action of the inner and outer rollers 20093, the position of the support 20092 is restricted from different directions, so that it will not easily deviate from the arc-shaped rail 2005, thereby ensuring that the laser particle size scanner 23 moves accurately along the predetermined arc-shaped rail 2005 track.

[0077] In this embodiment, please refer to Figures 1 to 10 , a test method for a test system for studying cement soil sedimentation effect, applicable to the test system for studying cement soil sedimentation effect as described above, comprising the following steps:

[0078] Acquisition of the original soil sample 21: Using a geological drill, the original soil sample 21 is drilled on site, and after being sent to the laboratory, it is filled into the organic glass cylinder 5 in layers of 50 cm and compacted, and finally the original soil fills the organic glass cylinder 5;

[0079] Original soil hole: Use Luoyang shovel to take soil from the center of the original soil to the bottom of the original soil. The diameter of the hole is 5cm, which is convenient for the spiral drill rod 17 to be placed.

[0080] High-pressure rotary jet pile simulation construction: by starting the linear power member 19, the connecting member 16 drives the auger rod 17 to move vertically downward into the soil hole in the organic glass tube 5, and slowly lower it to the bottom of the hole, and then use the cement slurry supply part 10 to make the cement slurry required for the test, and then start the cement slurry pump 11, the air compressor 12 and the drill rod power member 15, and then start the high-pressure rotary jet pile simulation construction according to the designed lifting speed and the rotation speed of the auger rod 17. During the construction process, the excess cement soil mixture enters the overflow tank 6 and enters the return slurry collection tube 8 through the return slurry pipe 7;

[0081] Detection of particle size of cement-soil mixture: After the high-pressure jet-jet pile simulation construction is completed, the laser particle size scanner 23 is driven by the linear drive member to move downward from the top of the organic glass tube 5 along the ball slide rail 22 at a uniform speed of 4m / min and scan the particle distribution of the test cement slurry mixture to generate a scanned image. After the laser particle size scanner 23 moves to the bottom of the organic glass tube 5, it moves upward at 10m / min and returns to the starting point, or the screw rod 2001 is driven by the motion power member 2008 to rotate and drive the motion block 2002 to transport at 4m / min for a certain distance and then stop. At this time, the rotating power component 2009 drives the laser The particle size scanner 23 moves around the organic glass tube 5, rotates to the position of the adjustment block 2007, and then changes to move in the opposite direction to return to the initial position. During the whole process, the laser particle size scanner 23 scans the particle distribution of the test cement slurry round to generate a scanned image. After the laser particle size scanner 23 moves to the bottom of the organic glass tube 5, it moves upward at 10m / min and returns to the starting point. Then, according to the imaging result of the laser particle size scanner 23, the characteristic particles in the image or the average value of the characteristic particles on the same plane are selected, and the bottom of the organic glass tube 5 is taken as the coordinate zero point. The characteristic particle position changes with time curve is plotted, and the curve is derived to obtain the characteristic particle movement speed change with time curve, and the curve is fitted to obtain the cement soil characteristic particle sedimentation rate equation;

[0082] Sampling for cement content test: After the high-pressure rotary jet pile simulation construction is completed, the plurality of sampling tubes 27 are connected to the plurality of connecting tubes 25 according to 0min, 5min, 10min, 30min, 1h, 2h, and 6h, and then the plurality of sampling valves 24 are opened, and the plurality of sampling tubes 27 are respectively extended into the organic glass cylinder 5 to sample the cement-soil mixture, and the sampling mass of each time is 30g. Then, the sampling tube 27 is pulled out and the sampling valve 24 is closed, and the sample is poured into a beaker, and the density of the sample is tested using a densitometer, and the cement content in the sample is tested using an improved EDTA titration test, and a density variation curve of the cement-soil mixed sample over time is plotted, and a cement content variation curve of the cement-soil mixed sample over time is plotted;

[0083] Among them, the EDTA improvement is a further improvement based on the chapter on cement or lime dosage determination method (EDTA titration method) in cement or lime stabilized materials in the "Testing Procedure for Inorganic Binder Stabilized Materials for Highway Engineering" (JTG E51-2009). The test method recommended in the specification is that the EDTA standard curve is linear when the cement content is within 10%. However, the cement content in high-pressure jet grouting pile construction is generally between 20% and 50%, and the cement content can be 35%. Therefore, the concentration of ammonium chloride solution should be adjusted to ensure that the standard curve is linear, and the amount of EDTA solution used in the titration test is within the linear section of the standard curve.

[0084] Sampling of strength test samples: After the high-pressure jet grouting pile simulation construction is completed, the plurality of standard sample cylinders 26 are respectively connected to the plurality of connecting pipes 25 at 0min, 5min, 10min, 30min, 1h, 2h, and 6h. The cement-soil mixture in the organic glass cylinder 5 is opened to flow into and fill the standard sample cylinder 26. The sample cylinder 26 is sent to a standard curing box for curing for 48h and then demoulded to produce a strength test sample. After the sample strength reaches the 28d-age strength, the sample strength is tested using a universal pressure testing machine.

[0085] Comprehensive analysis of test data: Comprehensive analysis of test data is conducted to determine the relationship between the strength of cement soil specimens and the cement content and density of the cement soil mixture, and to predict whether the strength of the pile top and pile body meets the requirements under the designed construction parameters.

[0086] In summary, the present invention uses the high-pressure rotary jet pile simulation construction module 3 to make high-pressure cement slurry into high-pressure rotary jet piles in the organic glass tube 5. After the construction is completed, the laser particle size scanner 23 is driven by the linear drive member at a fixed time to move downward at a uniform speed from the top of the organic glass tube 5 along the ball slide rail 22, and scan the particle distribution of the test cement slurry mixture to generate a scanned image. After the laser particle size scanner 23 moves to the bottom of the organic glass tube 5, it moves upward and returns to the starting point. Then, according to the imaging result of the laser particle size scanner 23, the characteristic particles in the image are selected, and the bottom of the organic glass tube 5 is taken as the coordinate zero point. The characteristic particle position changes with time curve is plotted, the curve is derived, and the characteristic particle movement speed changes with time curve is obtained. The curve is fitted to obtain The sedimentation rate equation of characteristic particles of cement soil is used to determine the sedimentation law of characteristic particles; when sampling the strength test samples, multiple standard sample tubes 26 are connected to multiple connecting pipes 25 respectively, and multiple sampling valves 24 are opened to allow the cement-soil mixture in the organic glass tube 5 to flow into and fill the standard sample tube 26, and the 28d strength is tested after curing, and the strength test samples are demoulded to be made, and the sample strength is tested using a universal pressure testing machine. When sampling the cement content test, multiple sampling valves 24 are opened at regular intervals to extend multiple sampling tubes 27 into the organic glass tube 5 to take samples, and EDTA titration test is used to determine the cement content in the sample, and a relationship curve between the sample cement content and the 28d strength and a curve of cement content change with time at different depths are established. The present invention can be used to study the settlement law of characteristic particles of cement-soil mixture of high-pressure jet grouting piles over time, the change law of cement content of cement-soil mixtures of different depths over time, the corresponding law of cement content and 28d strength, and realize the prediction of pile quality of high-pressure jet grouting piles under different construction parameters. It helps solve the problem of uneven strength distribution of the pile body due to cement precipitation in the pile body after the construction of high-pressure jet grouting piles is completed. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0087] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A test system for studying the sedimentation effect of cement soil, characterized in that: include: A sedimentation column module, the sedimentation column module comprising a base and an organic glass cylinder arranged above the base; A high-pressure jet grouting pile simulation construction module, wherein the high-pressure jet grouting pile simulation construction module is used to make high-pressure jet grouting piles in the organic glass cylinder; A particle size detection module for a cement-soil mixture, the particle size detection module for the cement-soil mixture comprising a ball slide rail vertically and fixedly arranged outside the organic glass tube, a laser particle size scanner mounted on the ball slide rail through a bracket, and a linear drive member, wherein the laser particle size scanner is driven by the linear drive member to move on the ball slide rail; A cement-soil mixture sampling module, the cement-soil mixture sampling module comprising a plurality of sampling valves, a plurality of connecting pipes, a plurality of standard sample cylinders and a plurality of sampling tubes, the sampling valves and the connecting pipes being equal in number and connected one-to-one, the plurality of connecting pipes being arranged at equal intervals along the axial direction of the side wall of the organic glass cylinder, the plurality of standard sample cylinders being respectively connected to the plurality of connecting pipes when sampling a strength test sample, and the cement-soil mixture in the organic glass cylinder being flowed into and filled with the standard sample cylinder by opening the plurality of sampling valves when sampling a cement content test, and the plurality of sampling tubes being respectively extended into the organic glass cylinder for sampling by opening the plurality of sampling valves.

2. The test system for studying cement soil precipitation effect according to claim 1, characterized in that: The settlement column module also includes an overflow trough arranged at the top of the organic glass tube and a return slurry collection tube for collecting excess cement-soil mixture slurry. The overflow trough transports the cement-soil mixture slurry overflowing from the top of the organic glass tube during the construction of the high-pressure rotary jet pile simulation construction module to the return slurry collection tube through a return slurry pipe.

3. The test system for studying the cement soil precipitation effect according to claim 1, characterized in that: The high-pressure jet grouting pile simulation construction module includes a guide rail vertical connecting rod fixedly connected to the top of the base, a connecting piece slidingly matched with the guide rail vertical connecting rod, a spiral drill rod rotatably arranged on the connecting piece, a nozzle fixedly connected to the bottom end of the spiral drill rod, a slurry supply and conveying part, an air supply and conveying part, a cement slurry supply part, a drill rod power part driving the spiral drill rod to rotate, and a linear power part driving the connecting piece to move up and down along the guide rail vertical connecting rod; One end of the slurry supply and delivery part and the air supply and delivery part both pass through the connecting piece and enter the auger rod to be connected to the nozzle, and the other ends of the slurry supply and delivery part and the air supply and delivery part are respectively connected to the cement slurry supply part and the air compressor, and a cement slurry pump is provided between the slurry supply and delivery part and the cement slurry supply part; The cement slurry supply part is used for providing cement slurry with a designed water-cement ratio for the test.

4. The test system for studying cement soil precipitation effect according to claim 3 is characterized by: The slurry supply and conveying part has the same structure as the air supply and conveying part. The slurry supply and conveying part comprises a first L-shaped tube, a spiral tube, and a second L-shaped tube. Both ends of the spiral tube are fixedly connected to one end of the first L-shaped tube and one end of the second L-shaped tube respectively. The other end of the first L-shaped tube of the slurry supply and transportation part is connected to the cement slurry supply part through the cement slurry pump, and the other end of the first L-shaped tube of the air supply and transportation part is connected to the air compressor; The second L-shaped tube of the slurry supply and conveying part and the second L-shaped tube of the air supply and conveying part both pass through the connecting piece, enter the auger rod and are connected to the nozzle.

5. The test system for studying cement soil precipitation effect according to claim 3 is characterized by: The cement slurry supply part includes a production tank, a mixing shell fixedly connected to the top of the production tank, a raw material mixing mechanism arranged in the mixing shell, a rotating cylinder rotatably connected to the inner wall of the production tank, a cross fixedly connected to the inner wall of the rotating cylinder, a stirring column fixedly connected to the middle position of the cross, stirring blades, and a water spraying mechanism arranged below the rotating cylinder. The top of the rotating cylinder has a plurality of upward-facing meshing teeth in the circumferential direction, the raw material mixing mechanism is transmission-connected to the meshing teeth on the rotating cylinder, there are a plurality of stirring blades, and the plurality of stirring blades are spaced apart along the axial and circumferential directions of the stirring column, the mixing shell has two feed inlets, and the bottom of the production tank has a discharge port.

6. The test system for studying the cement soil precipitation effect according to claim 5, characterized in that: The raw material mixing mechanism includes two horizontal shafts horizontally rotatably connected to the mixing shell, two crank cylinders respectively fixedly connected to the two horizontal shafts, two connecting cylinders respectively communicated with the two crank cylinders, a mixing spherical cavity located between and connected to the two connecting cylinders, a hybrid power component driving the horizontal shaft to rotate, two rotating discs and two transmission gears, the two transmission gears are respectively coaxially fixedly matched with the two horizontal shafts, and both are engaged with the meshing teeth on the rotating cylinder for transmission, the two rotating discs are respectively coaxially fixedly matched with the two horizontal shafts, each of the rotating discs is slidably matched with the bottom of the feed inlet located above, and each of the rotating discs has a plurality of transfer channels circumferentially and toward its own axial direction on the side wall, each of the transfer channels is communicated with the crank cylinder, and the mixing spherical cavity has a plurality of leakage holes.

7. The test system for studying the cement soil precipitation effect according to claim 5, characterized in that: The water spraying mechanism includes an annular tube fixedly connected to the inner wall of the production tank and located below the rotating cylinder, and a water spraying head. There are multiple water spraying heads, and the multiple water spraying heads are arranged on the annular tube at a first spacing, and the water spraying direction is toward the central axis direction of the stirring column. Each of the water spraying heads is provided with a control valve.

8. A test method for a test system for studying the sedimentation effect of cement soil, characterized in that: The test system for studying the cement soil precipitation effect as claimed in claim 3 comprises the following steps: Original soil sample acquisition: using a geological drill, drill on-site to obtain original soil samples, send them to the laboratory, fill them into the organic glass cylinder in layers of 50 cm and compact them, and finally fill the organic glass cylinder with original soil; Drilling holes in the original soil: Use a Luoyang shovel to drill holes in the center of the original soil until the bottom of the original soil. The diameter of the drilling hole is 5 cm. High-pressure jet grouting pile simulation construction: by starting the linear power part, the connecting part drives the auger rod to move vertically downward into the soil-taking hole in the organic glass tube, and slowly lowers it to the bottom of the hole, and then uses the cement slurry supply part to make the cement slurry required for the test, and then starts the cement slurry pump, the air compressor and the drill rod power part, and then starts the high-pressure jet grouting pile simulation construction according to the designed lifting speed and the rotation speed of the auger rod; Detection of particle size of cement-soil mixture: After the high-pressure jet-jet pile simulation construction is completed, the laser particle size scanner is driven by the linear drive member to move downward from the top of the organic glass tube at a uniform speed of 4 m / min along the ball slide rail and scan the particle distribution of the test cement slurry mixture to generate a scanned image. After the laser particle size scanner moves to the bottom of the organic glass tube, it moves upward at 10 m / min and returns to the starting point. Then, according to the imaging results of the laser particle size scanner, the characteristic particles in the image are selected, and the bottom of the organic glass tube is taken as the coordinate zero point. The characteristic particle position changes with time curve is plotted, and the curve is derived to obtain the characteristic particle movement speed change curve with time. The curve is fitted to obtain the cement soil characteristic particle sedimentation rate equation; Sampling for cement content test: After the high-pressure rotary jet pile simulation construction is completed, the plurality of sampling tubes are connected to the plurality of connecting tubes according to 0min, 5min, 10min, 30min, 1h, 2h, and 6h, and then the plurality of sampling valves are opened, and the plurality of sampling tubes are respectively extended into the organic glass cylinder to sample the cement-soil mixture, and the sampling mass of each time is 30g. Then the sampling tube is pulled out and the sampling valve is closed, and the sample is poured into a beaker, and the density of the sample is tested using a densitometer, and the cement content in the sample is tested using an improved EDTA titration test, and a density variation curve of the cement-soil mixed sample over time is plotted, and a cement content variation curve of the cement-soil mixed sample over time is plotted; Sampling of strength test samples: After the simulation construction of high-pressure jet grouting piles is completed, the plurality of standard sample cylinders are respectively connected to the plurality of connecting pipes at 0min, 5min, 10min, 30min, 1h, 2h, and 6h. The cement-soil mixture in the organic glass cylinder is opened to flow into and fill the standard sample cylinder. The cylinder is sent to a standard curing box for curing for 48h and then demoulded to produce strength test samples. After the sample strength reaches the 28d-age strength, the sample strength is tested using a universal pressure testing machine. Comprehensive analysis of test data: Comprehensive analysis of test data is conducted to determine the relationship between the strength of cement soil specimens and the cement content and density of the cement soil mixture, and to predict whether the strength of the pile top and pile body meets the requirements under the designed construction parameters.

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