Horizontal static penetration calibration tank system and its use method

Abstract

The present invention relates to the field of indoor calibration technology for geotechnical engineering, and in particular to a horizontal static penetration calibration tank system and a method for using the same. The system comprises a soil sample tank, a glue water bag, and a horizontal penetration device. The top of the soil sample tank is provided with a calibration tank cover, and the bottom of the soil sample tank is fixed with a calibration tank base. A closed cavity is formed between the calibration tank cover, the soil sample tank, and the calibration tank base. The cavity contains a rubber water bag and a test soil sample. The rubber water bag is located above the test soil sample. A horizontal penetration device is provided through the side wall of the soil sample tank containing the soil sample. The system can simulate the horizontal static penetration under the stress conditions of the actual soil layer, provide a horizontal static penetration stress condition close to the field for soil with uncertain engineering parameters, and provide a sufficient experimental basis for accurately establishing a horizontal static penetration data interpretation model.

Description

Technical Field

[0001] The present invention relates to the technical field of geotechnical engineering indoor calibration, in particular to a horizontal static penetration calibration tank system and a use method thereof. Background Art

[0002] Geotechnical engineering parameters have large spatial variability and the cost of obtaining parameters is high. The pore pressure static penetration equipment can simultaneously obtain the cone tip resistance q of the original soil. t , side wall resistance f s The pore water pressure u0 has the advantages of continuity, original state, and economy, and is widely used in geotechnical engineering investigation and testing.

[0003] The widespread application of cone penetration testing requires an accurate data interpretation model. Currently, these models are primarily developed by establishing empirical relationships or theoretical models based on field cone penetration test results and laboratory experiments using field soil sampling. Due to the significant disturbance associated with soil sampling, laboratory test results may not be consistent with field soil properties, leading to significant errors in the data interpretation model. Therefore, laboratory calibration tanks are widely used in cone penetration testing calibration experiments.

[0004] Existing static penetration calibration tanks can usually only perform vertical penetration and cannot obtain data on horizontal penetration status, resulting in inaccurate interpretation models. Current conventional static penetration calibration tanks are unable to interpret and verify the parameters of horizontal static penetration equipment and cannot adapt to the new requirements for the development of static penetration equipment. Therefore, it is necessary to design a new calibration tank system that can perform horizontal penetration of static penetration equipment. If the theoretical interpretation system for horizontal static penetration is successfully established, it can be organically combined with shield excavation, horizontal directional drilling, etc., to provide real-time changes in the rock and soil parameters in front of the face, and to adjust construction parameters in a timely manner to ensure the stability of the soil in front. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and propose a horizontal static penetration calibration tank system and a method of using the same, which can simulate the horizontal static penetration under the actual soil stress conditions, and can provide a horizontal static penetration stress condition close to the site for soil with uncertain engineering parameters, and provide a sufficient experimental basis for accurately establishing a horizontal static penetration data interpretation model.

[0006] The technical solution of the present invention is: a horizontal hydrostatic penetration calibration tank system, including a soil sample tank, which also includes a rubber water bag and a horizontal penetration device. The top of the soil sample tank is provided with a calibration tank top cover, and the bottom of the soil sample tank is fixed with a calibration tank base. A closed cavity is formed between the calibration tank top cover, the soil sample tank and the calibration tank base. The cavity contains the rubber water bag and the test soil sample. The rubber water bag is located above the test soil sample. A horizontal penetration device is provided through the side wall of the soil sample tank containing the soil sample.

[0007] In the present invention, the horizontal penetration device includes a horizontal hydrostatic sounding rod, which includes a conical probe and a rod body. The probe is solid, a cavity is provided in the rod body, and a permeable stone is provided between the probe and the rod body. The probe and the rod body are composed of symmetrical upper and lower parts. The upper probe and the lower probe, as well as the upper rod body and the lower rod body are fixedly connected by a mortise and tenon structure. A cone-tip strain column is provided in the upper probe and the lower probe respectively, and a cone-tip strain gauge is provided on the cone-tip strain column. A side friction sleeve is provided on the outer side of the front end of the rod body, and a side friction resistance strain gauge is provided on the inner side of the side friction sleeve. A closed chamber is provided on the side of the internal cavity of the rod body close to the probe, and a pore pressure sensor is provided in the chamber. The permeable stone is arranged in a ring shape along the circumferential direction of the rear part of the probe, and a water hole is provided at the corresponding rear part of the probe. One end of the water hole is connected to the annular cavity surrounded by the permeable stone, and the other end of the water hole is connected to the closed chamber. A posture sensor is also provided in the cavity of the rod body.

[0008] The calibration tank cover and the top of the soil sample tank are fixedly connected by a buckle structure. The bottom of the calibration tank cover is provided with a cover buckle. Correspondingly, a plurality of annular protrusions are arranged at intervals along the circumferential direction of the outer wall of the top of the soil sample tank. When the protrusions are arranged in the cover buckle, the calibration tank cover and the soil sample tank are fixedly connected.

[0009] The top surface of the calibration tank cover is provided with a plurality of handles.

[0010] A water filling hole is provided on the side wall of the upper part of the soil sample tank. The water filling channel of the rubber water bag passes through the water filling hole and extends out of the soil sample tank and is connected with an external water pump. A flow sensor is provided at the water filling channel.

[0011] A permeable plate and a permeable plate bottom cover are arranged above the calibration tank base from top to bottom. A cross-shaped permeable plate drainage channel is provided on the permeable plate. The permeable plate drainage channel is composed of several drainage holes that are spaced apart and pass through the permeable plate. A cross-shaped drainage groove is provided on the permeable plate bottom cover. The drainage groove and the permeable plate drainage channel are arranged correspondingly. Several drainage channels are spaced apart along the circumferential direction of the outer side wall of the calibration tank base, and a drainage valve is provided on the drainage channel.

[0012] The horizontal penetration device also includes several holders and screw rods spaced apart in the horizontal direction. The holders include holder I, holder II and holder III. The two ends of holder I in the horizontal direction are fixedly connected to the outer wall of the soil sample tank through guide support rods. The outer end of the guide support rod is fixedly connected to holder I. The inner end of the guide support rod is fixedly connected to the outer wall of the soil sample tank through the bracket base. Holder II and holder III are arranged between holder I and the outer wall of the soil sample tank in sequence. A screw and a horizontal static sounding rod are arranged between the two guide support rods. The rod and screw pass through the base II and base III respectively. The base II, base III and the guide support rod are respectively slidingly connected. The outer end of the screw is connected to the motor output shaft fixed on the base I, and the inner end of the screw is connected to the base III. The screw passes through the threaded hole in the base II, and the screw and the threaded hole in the base II are transmitted by threaded engagement. The outer end of the horizontal static sounding rod is fixedly connected to the base II, and the inner end of the horizontal static sounding rod is a free end. A socket is provided in the base III, and the inner end of the horizontal static sounding rod passes through the socket of the base III.

[0013] The present invention also includes a method for using the above-mentioned horizontal cone penetration probe calibration tank system, which includes the following steps:

[0014] S1. Insert the horizontal hole cover into the horizontal penetration hole on the side wall of the soil sample tank to ensure the sealing of the side wall of the soil sample tank;

[0015] S2. Consolidation of test soil samples:

[0016] The test soil samples are evenly placed in the soil sample tank, the rubber water bag is placed above the test soil samples, the calibration tank cover is covered on the rubber water bag, water is filled into the rubber water bag, and the water pressure is controlled. The reaction force of the rubber water bag and the calibration tank cover provides consolidation pressure for the soil in the soil sample tank.

[0017] S3. The motor starts to move the horizontal hydrostatic penetration rod horizontally toward the soil sample tank and penetrate the soil sample in the soil sample tank through the horizontal penetration hole on the side wall of the soil sample tank. During the horizontal penetration process, the electrical signal detected by the horizontal hydrostatic penetration rod is used to obtain the undrained shear strength of the soil sample in the soil sample tank:

[0018] During the horizontal penetration process, the horizontal static penetration rod obtains the electrical signal ε1 of the cone tip strain gauge, the electrical signal ε2 of the side friction resistance strain gauge, and the electrical signal ζ of the pore water pressure sensor. The undrained shear strength of the consolidated soil sample is obtained by the following formula:

[0019]

[0020] Among them, k q is the cone tip resistance calibration coefficient; a is the cone tip strain gauge coefficient; E q is the elastic modulus of the strain column; η is the horizontal correction coefficient; σ v0Overburden stress provided to the rubber water bag; N kt is the cone tip resistance coefficient; η=(1+K) / K, where K is the horizontal stress coefficient, and η for normally consolidated soil is 0.65; A q is the base area of the cone tip strain column.

[0021] In the above step S2, the soil settlement per unit time is calculated according to the following formula:

[0022]

[0023] where Δv n is the water intake of the rubber water bag on the nth day of consolidation, is the total water inflow of the rubber water bag. When S≤0.2%, the soil sample is considered to be consolidated and the formula is used.

[0024] Δv i / A,

[0025] Obtain the height change of the rubber water bag within a certain period of time, where A is the bottom area of the rubber water bag.

[0026] In the above step S3, during the penetration of the horizontal hydrostatic sounding rod, the cone tip strain gauge in the rod is used to detect the cone tip resistance during the penetration process and convert it into an electrical signal, the pore water pressure during the penetration process is detected by the pore pressure sensor and converted into an electrical signal, the side friction resistance during the penetration process is detected by the side friction resistance strain gauge and converted into an electrical signal, the posture of the entire rod during the penetration process is detected by the posture sensor, and the posture is transmitted to the motor in real time, and the penetration posture of the horizontal hydrostatic sounding rod is fine-tuned by the motor to ensure real-time horizontal penetration of the horizontal hydrostatic sounding rod.

[0027] The beneficial effects of the present invention are:

[0028] (1) The system simulates soil stress through rubber water bags and can simulate horizontal static penetration under actual soil stress conditions. Through multiple horizontal penetration devices, each test group can conduct multiple penetrations, and multiple tests can be conducted after one consolidation, which greatly improves work efficiency. It can provide soil with uncertain engineering parameters with horizontal static penetration stress conditions close to the site, and provide a sufficient experimental basis for accurately establishing a horizontal static penetration data interpretation model.

[0029] (2) Based on the cone tip resistance, side friction resistance, and pore water pressure obtained from the horizontal static penetration test, the existing vertical CPTu test research can be further expanded and applied to the acquisition of geotechnical engineering parameters such as horizontal undrained shear strength and horizontal permeability coefficient. Based on this, a theoretical system of horizontal static penetration test can be established, which will further expand the application scope of static penetration test. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the present invention;

[0031] Figure 2 It is a schematic diagram of the main cross-sectional structure of the soil sample tank;

[0032] Figure 3 It is a structural diagram of the calibration tank top cover;

[0033] Figure 4 It is a structural diagram of the soil sample tank;

[0034] Figure 5 It is a structural diagram of the permeable board;

[0035] Figure 6 It is a structural diagram of the bottom cover of the permeable plate;

[0036] Figure 7 It is a structural diagram of the bottom cover of the calibration tank;

[0037] Figure 8 It is a structural diagram of the horizontal penetration device;

[0038] Figure 9 This is a structural diagram of a horizontal static penetration probe rod;

[0039] Figure 10 It is a schematic diagram of the partial cross-sectional structure of the horizontal static penetration probe rod.

[0040] In the figure: 1 handle; 2 calibration tank top cover; 3 soil sample tank; 4 water filling channel; 5 horizontal penetration device; 6 calibration tank base; 7 horizontal hole cover; 8 drainage valve; 9 rubber water bag; 10 flow sensor; 11 permeable plate; 12 permeable plate bottom cover; 13 top cover buckle; 14 protrusion; 15 water filling hole; 16 horizontal penetration hole; 17 permeable plate drainage channel; 18 drainage trough; 19 drainage channel; 20 holder I; 21 holder II; 22 holder III; 23 guide support rod; 24 bracket base; 25 horizontal static penetration probe rod; 26 motor; 27 screw; 28 probe; 29 probe rod body; 30 cone-tip strain gauge; 31 cone-tip strain column; 32 pore pressure sensor; 33 side friction resistance strain gauge; 34 attitude sensor; 35 permeable stone; 36 side friction sleeve. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] The following description sets forth specific details to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art will be able to make similar generalizations without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0043] like Figure 1 and Figure 2 As shown, the horizontal hydrostatic penetration calibration tank system of the present invention includes a soil sample tank 3, a rubber water bladder 9, and a horizontal penetration device 5. A calibration tank cover 2 is located on the top of the soil sample tank 3, and a calibration tank base 6 is fixed to the bottom of the soil sample tank 3. The calibration tank cover 2, soil sample tank 3, and calibration tank base 6 form a closed cavity, which contains the rubber water bladder 9 and the test soil sample. The rubber water bladder 9 is located above the test soil sample. The horizontal penetration device 5 is installed through the side wall of the soil sample tank 3 containing the soil sample.

[0044] like Figure 2 and Figure 3 As shown, the calibration tank cover 2 and the top of the soil sample tank 3 are fixedly connected by a snap-fit structure: a top cover snap-fit 13 is provided at the bottom of the calibration tank cover 2, and a number of annular protrusions 14 are correspondingly provided at intervals along the circumferential direction of the top outer wall of the soil sample tank 3. When the protrusions 14 are set in the top cover snap-fit 13, the calibration tank cover 2 and the soil sample tank 3 can be fixedly connected. Several handles 1 are provided on the top surface of the calibration tank cover 2. By applying force to the handles 1, the calibration tank cover 2 is rotated. When the calibration tank cover 2 is rotated until the protrusions 14 on the top of the soil sample tank enter the top cover snap-fit 13, the connection between the calibration tank cover 2 and the soil sample tank 3 is achieved. In addition, since the calibration tank cover 2 is located above the rubber water bag 9, the calibration tank cover 2 provides a reverse pressure on the rubber water bag 9.

[0045] The side wall of the upper part of the soil sample tank 3 is provided with a water filling hole 15, such as Figure 2 As shown, the water filling channel 4 of the rubber water bladder 9 extends through the water filling hole 15 and out of the soil sample tank 3. It is connected to an external water pump. Under the action of the water pump, water flows through the water filling channel 4 into the rubber water bladder 9, providing consolidation pressure for the soil sample. A flow sensor 10 is installed at the water filling channel 4 of the rubber water bladder 9 to control the water inflow of the rubber water bladder.

[0046] The top of the calibration tank base 6 is provided with a water-permeable plate 11 and a water-permeable plate bottom cover 12 in order from top to bottom. Since the calibration tank base 6 is circular, the corresponding water-permeable plate 11 and the water-permeable plate bottom cover 12 are both circular. Figure 5 As shown, the permeable plate 11 is provided with a cross-shaped permeable plate drainage channel 17, which is composed of a number of drainage holes that are spaced apart and penetrate the permeable plate. Figure 6As shown, a cross-shaped drainage groove 18 is provided on the bottom cover 12 of the permeable plate, and the drainage groove 18 is corresponding to the drainage channel 17 of the permeable plate. Figure 7 As shown, the calibration tank base is provided with several drainage channels 19 spaced apart along its circumference, and each drainage channel 19 is provided with a drainage valve 8. During the soil sample consolidation process, the water flowing out of the soil sample flows out in sequence through the drainage channel 17 of the permeable plate, the drainage groove 18 of the bottom cover of the permeable plate, and the drainage channel 19 of the calibration tank base.

[0047] A test soil sample is placed below the rubber water bag 9 in the soil sample tank. Several horizontal penetration devices 5 are installed through the sidewall of the soil sample tank containing the test soil sample, and corresponding horizontal penetration holes 16 are provided in the sidewall of the soil sample tank. During the soil sample consolidation process, horizontal hole cover plates 7 are placed in the horizontal penetration holes 16 to seal the sidewall of the soil sample tank 3.

[0048] like Figure 8 As shown, the horizontal penetration device includes several holders, screws, and horizontal hydrostatic sounding rods spaced apart in the horizontal direction. The holders include holder I 20, holder II 21, and holder III 22. The two ends of holder I 20 in the horizontal direction are fixedly connected to the outer wall of the soil sample tank 3 via guide support rods 23. The outer end of the guide support rod 23 is fixedly connected to holder I 20, and the inner end of the guide support rod 23 is fixedly connected to the outer wall of the soil sample tank 3 via a bracket base 24. Holder II 21 and holder III 22 are sequentially provided between holder I 20 and the outer wall of the soil sample tank 3. A screw 27 and a horizontal hydrostatic sounding rod 25 are provided between the two guide support rods 23. The two guide support rods 23 and the screw 27 pass through holder II 21 and holder III 22, respectively. Holder II 21 and holder III 22 are respectively connected to the guide support rods 23 in a sliding manner. The outer end of screw 27 is connected to the output shaft of motor 26, which is fixed to base I 20. The inner end of screw 27 is connected to base III 22. Screw 27 passes through a threaded hole in base II 21, and screw 27 and the threaded hole in base II 21 are engaged by threads. The outer end of the horizontal hydrostatic sounding probe 25 is fixedly connected to base II 21, while the inner end of the horizontal hydrostatic sounding probe 25 is free. Base III 22 has a socket, and the inner end of the horizontal hydrostatic sounding probe 25 passes through the socket of base III 22.

[0049] During forward rotation of motor 26, screw 27 is driven to rotate. Through the threaded transmission between screw 27 and holder II 21, holder II 21 moves along the axial direction of screw 27 toward soil sample tank 3, thereby driving horizontal hydrostatic probe 25, which is fixedly connected to holder II 21, to move horizontally and gradually approach soil sample tank 3. During this horizontal movement, horizontal hydrostatic probe 25 passes through horizontal penetration hole 16 in the side wall of soil sample tank 3 and is inserted into the test soil sample in soil sample tank 3, thereby collecting soil sample information. After the information collection is completed, motor 26 is reversed, driving screw 27 to rotate. Through the threaded transmission between screw 27 and holder II 21, holder II 21 drives horizontal hydrostatic probe 25 to move away from soil sample tank 3 until it leaves the test soil sample.

[0050] like Figure 9 and Figure 10 As shown, the horizontal cone penetration probe 25 includes a tapered probe head 28 and a probe body 29. The probe head 28 is solid, and the probe body 29 defines a cavity. A permeable stone 35 is positioned between the probe head 28 and the probe body 29. In this embodiment, the probe head 28 and the probe body 29 each consist of symmetrical upper and lower portions. The upper and lower probe heads, as well as the upper and lower probe bodies, are fixedly connected by a mortise and tenon structure. The mortise and tenon joints of the mortise and tenon structure are provided with flexible material to ensure relative free deformation of the upper and lower probe heads, as well as the upper and lower probe bodies.

[0051] A cone-tip strain column 31 is provided in the upper probe and the lower probe respectively, and a cone-tip strain gauge 30 is provided on the cone-tip strain column 31. When the probe 28 of the horizontal static penetration probe rod is inserted into the soil sample, the cone-tip strain column 31 in the probe will be deformed. The cone-tip strain gauge 30 will detect the deformation of the cone-tip strain column 31 and convert the detected deformation into an electrical signal.

[0052] A side friction sleeve 36 is provided on the outside of the front end of the probe rod body 29, and a side friction resistance strain gauge 33 is provided on the inside of the side friction sleeve 36. When the horizontal hydrostatic sounding probe rod 25 is inserted into the soil sample, the side friction sleeve 36 is squeezed by the soil sample and deformed. The side friction resistance strain gauge 33 is used to detect the deformation of the side friction sleeve 36 and convert the detected deformation into an electrical signal. A sealed chamber is provided on the side of the internal cavity of the probe rod body close to the probe, and a pore pressure sensor 32 is provided in the chamber. The permeable stone 35 is arranged in a ring shape along the circumferential direction of the rear part of the probe, and a water hole is provided at the rear part of the corresponding probe. During the penetration of the horizontal hydrostatic sounding probe rod, the moisture in the soil sample will pass through the permeable stone 35 and enter the sealed chamber at the front end of the probe rod body along the water hole in the probe. At this time, the pore pressure sensor 32 detects the pore water pressure and converts the detected pore water pressure into an electrical signal. At the same time, a posture sensor 34 is provided in the cavity inside the probe rod body. The posture sensor 34 is used to monitor the posture of the probe and the probe rod body in real time during the movement process to ensure the horizontal penetration of the probe and the probe rod body.

[0053] The present invention also includes a method for using the above-mentioned horizontal static penetration probe rod calibration tank system, which includes the following steps.

[0054] In the first step, the horizontal hole cover plate 7 is inserted into the horizontal penetration hole 16 of the side wall of the soil sample tank to ensure the sealing of the side wall of the soil sample tank.

[0055] In the second step, the test soil sample is evenly placed in the soil sample tank 3. The rubber water bladder 9 is placed above the test soil sample, and the calibration tank cover 2 is placed on top of the rubber water bladder 9. The calibration tank cover 2 is rotated by the handle 1 and fixed to the top of the soil sample tank 3. A water pump is used to fill the rubber water bladder 9 with water and control the water pressure. The reaction force between the rubber water bladder 9 and the calibration tank cover 2 provides consolidation pressure for the soil in the soil sample tank.

[0056] During the consolidation process, the soil settlement per unit time can be calculated based on the total water volume of the rubber water bag and the water volume per unit time. where Δv n is the water inflow on the nth day of consolidation, is the total water inflow. If S≤0.2%, consolidation is considered complete and can be calculated by the formula Δv i / A, where A is the bottom area of the rubber water bag, and the height change of the rubber water bag within a certain period of time is obtained.

[0057] In the third step, the motor 26 is activated to drive the horizontal static penetration probe 25 to move horizontally toward the soil sample tank and penetrate into the soil sample in the soil sample tank through the horizontal penetration hole 16 on the side wall of the soil sample tank.

[0058] During the penetration of the horizontal hydrostatic sounding rod, the cone tip resistance during the penetration process is detected by the cone tip strain gauge 30 in the rod, the pore water pressure during the penetration process is detected by the pore pressure sensor 32, the side friction resistance during the penetration process is detected by the side friction resistance strain gauge 33, and the posture of the entire rod during the penetration process is detected by the posture sensor 34, and the posture is transmitted to the motor 26 in real time. The penetration posture of the horizontal hydrostatic sounding rod 25 is fine-tuned by the motor 26 to ensure real-time horizontal penetration of the horizontal hydrostatic sounding rod 25.

[0059] The large amount of data obtained by the horizontal hydrostatic penetration probe can be analyzed to obtain the data correlation between horizontal penetration and vertical penetration for subsequent model building.

[0060] Cone tip resistance q c The calculation formula is:

[0061]

[0062] Where: q c is the cone tip resistance, a is the cone tip strain gauge coefficient, ε1 is the cone tip strain gauge electrical signal, E q is the elastic modulus of the strain column, A q is the base area of the cone tip strain column, k q is the cone tip resistance calibration coefficient.

[0063] Lateral friction resistance f s The calculation formula is:

[0064]

[0065] Where: f s is the cone tip resistance, b is the side friction resistance strain gauge coefficient, ε2 is the side friction resistance strain gauge electrical signal, E is the side friction sleeve elastic modulus, A f is the bottom area of the side friction sleeve, k f is the side friction calibration coefficient.

[0066] The calculation formula of pore water pressure u2 is:

[0067] u2=k u ξ

[0068] Where: u2 is the pore water pressure, k u is the pore water pressure calibration coefficient, and ζ is the electrical signal of the pore water pressure sensor.

[0069] Undrained shear strength S u The calculation formula is:

[0070]

[0071] Where: η is the horizontal correction coefficient, η = (1 + K) / K, where K is the horizontal stress coefficient. For normally consolidated soil, η can be taken as 0.65.

[0072] The undrained shear strength can be directly calculated by obtaining the cone tip strain gauge electrical signal ε1, the side friction resistance strain gauge electrical signal ε2, and the pore water pressure sensor electrical signal ζ during the horizontal penetration of the horizontal static penetration probe:

[0073]

[0074] Among them, σ v0 Overburden stress provided by the rubber water bag, N kt is the cone tip drag coefficient.

[0075] The above is a detailed introduction to the horizontal hydrostatic penetration calibration tank system and its use method provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The above description of the disclosed embodiments enables professionals in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for using a horizontal static penetration calibration tank system, characterized in that: The following steps are involved: S1. Insert the horizontal hole cover into the horizontal penetration hole on the side wall of the soil sample tank to ensure the sealing of the side wall of the soil sample tank; S2. Consolidation of test soil samples: Place the test soil sample evenly in the soil sample tank, place the rubber water bag on top of the test soil sample, cover the calibration tank cover on top of the rubber water bag, fill the rubber water bag with water, and control the water pressure. The reaction force between the rubber water bag and the calibration tank cover provides consolidation pressure for the soil in the soil sample tank. S3. The motor starts to move the horizontal hydrostatic penetration rod horizontally toward the soil sample tank and penetrate the soil sample in the soil sample tank through the horizontal penetration hole on the side wall of the soil sample tank. During the horizontal penetration process, the electrical signal detected by the horizontal hydrostatic penetration rod is used to obtain the undrained shear strength of the soil sample in the soil sample tank: During the horizontal penetration process, the horizontal static penetration rod obtains the electrical signal ε1 of the cone tip strain gauge, the electrical signal ε2 of the side friction resistance strain gauge, and the electrical signal ζ of the pore water pressure sensor. The undrained shear strength of the consolidated soil sample is obtained by the following formula: Among them, k q is the cone tip resistance calibration coefficient; a is the cone tip strain gauge coefficient; E q is the elastic modulus of the strain column; η is the horizontal correction coefficient; σ v0 Overburden stress provided to the rubber water bag; N kt is the cone tip resistance coefficient; η=(1+K) / K, where K is the horizontal stress coefficient, and η for normally consolidated soil is 0.65; A q is the base area of the cone tip strain column; A horizontal static penetration calibration tank system comprises a soil sample tank (3), a rubber water bag (9) and a horizontal penetration device (5); a calibration tank cover (2) is provided on the top of the soil sample tank (3); a calibration tank base (6) is fixed on the bottom of the soil sample tank (3); a closed cavity is formed between the calibration tank cover (2), the soil sample tank (3) and the calibration tank base (6); the rubber water bag (9) and a test soil sample are contained in the cavity; the rubber water bag (9) is located above the test soil sample; and a horizontal penetration device (5) is provided through the side wall of the soil sample tank (3) containing the soil sample; The horizontal penetration device comprises a horizontal static penetration probe rod (25), the horizontal static penetration probe rod (25) comprises a conical probe (28) and a probe rod body (29), the probe (28) is solid, a cavity is provided in the probe rod body (29), a permeable stone (35) is provided between the probe (28) and the probe rod body (29), the probe (28) and the probe rod body (29) are composed of symmetrical upper and lower parts, the upper probe and the lower probe, as well as the upper probe rod body and the lower probe rod body are fixedly connected by a mortise and tenon structure, the upper probe and the lower probe are respectively provided with a cone tip strain column (31), the cone tip strain column (31) is provided in the upper probe and the lower probe, and the cone tip strain column (31) is provided in the lower probe. A conical strain gauge (30) is provided on the variable column (31), a side friction sleeve (36) is provided on the outer side of the front end of the probe rod body (29), and a side friction resistance strain gauge (33) is provided on the inner side of the side friction sleeve (36). A sealed chamber is provided on the side of the inner cavity of the probe rod body close to the probe, and a pore pressure sensor (32) is provided in the chamber. A permeable stone (35) is arranged in an annular shape along the circumferential direction of the rear part of the probe, and a water hole is provided at the rear part of the corresponding probe. One end of the water hole is connected to the annular cavity surrounded by the permeable stone, and the other end of the water hole is connected to the sealed chamber. A posture sensor (34) is also provided in the cavity of the probe rod body.

2. The method according to claim 1, characterized in that In the above step S2, the soil settlement per unit time is calculated according to the following formula: where Δv n is the water intake of the rubber water bag on the nth day of consolidation, is the total water inflow of the rubber water bag. When S≤0.2%, the soil sample is considered to be consolidated and the formula is used. Δv i / A, Obtain the height change of the rubber water bag within a certain period of time, where A is the bottom area of the rubber water bag.

3. The method according to claim 1, characterized in that In the above step S3, during the penetration of the horizontal hydrostatic sounding rod, the cone tip strain gauge in the rod is used to detect the cone tip resistance during the penetration process and convert it into an electrical signal, the pore water pressure during the penetration process is detected by the pore pressure sensor and converted into an electrical signal, the side friction resistance during the penetration process is detected by the side friction resistance strain gauge and converted into an electrical signal, the posture of the entire rod during the penetration process is detected by the posture sensor, and the posture is transmitted to the motor in real time, and the penetration posture of the horizontal hydrostatic sounding rod is fine-tuned by the motor to ensure real-time horizontal penetration of the horizontal hydrostatic sounding rod.

4. The method according to claim 1, wherein The calibration tank top cover (2) and the top of the soil sample tank (3) are fixedly connected via a snap-fit structure; a top cover snap-fit (13) is provided at the bottom of the calibration tank top cover (2); and correspondingly, a plurality of annular protrusions (14) are provided at intervals along the circumferential direction of the top outer wall of the soil sample tank (3); when the protrusions (14) are arranged in the top cover snap-fit (13), a fixed connection between the calibration tank top cover (2) and the soil sample tank (3) is achieved; The top surface of the calibration tank cover (2) is provided with a plurality of handles (1).

5. The method according to claim 1, wherein A water filling hole (15) is provided on the side wall of the upper portion of the soil sample tank (3); a water filling channel (4) of the rubber water bag (9) extends out of the soil sample tank (3) through the water filling hole (15) and is connected to an external water pump; a flow sensor (10) is provided at the water filling channel (4).

6. The method according to claim 1, characterized in that A permeable plate (11) and a permeable plate bottom cover (12) are sequentially provided above the calibration tank base (6) from top to bottom. A cross-shaped permeable plate drainage channel (17) is provided on the permeable plate (11). The permeable plate drainage channel (17) is composed of a plurality of drainage holes that are arranged at intervals and penetrate the permeable plate. A cross-shaped drainage groove (18) is provided on the permeable plate bottom cover (12). The drainage groove (18) and the permeable plate drainage channel (17) are arranged correspondingly. A plurality of drainage channels (19) are arranged at intervals along the circumferential direction of the outer wall of the calibration tank base. A drainage valve (8) is provided on the drainage channel (19).

7. The method according to claim 1, characterized in that The horizontal penetration device also includes a plurality of holders and screw rods arranged at intervals in the horizontal direction, wherein the holders include holder I (20), holder II (21), and holder III (22), and the two ends of the holder I (20) in the horizontal direction are fixedly connected to the outer wall of the soil sample tank (3) through the guide support rod (23), the outer end of the guide support rod (23) is fixedly connected to the holder I (20), and the inner end of the guide support rod (23) is fixedly connected to the outer wall of the soil sample tank (3) through the bracket base (24), and the holder II (21) and the holder III (22) are sequentially arranged between the holder I (20) and the outer wall of the soil sample tank (3), and a screw rod (27) and a horizontal static sounding rod (25) are arranged between the two guide support rods (23). The two guide support rods (23) and the screw rod ( 27) pass through the card seat II (21) and the card seat III (22) respectively, and the card seat II (21), the card seat III (22) and the guide support rod (23) are all slidingly connected. The outer end of the screw rod (27) is connected to the output shaft of the motor (26) fixed on the card seat I (20), and the inner end of the screw rod (27) is connected to the card seat III (22). The screw rod (27) passes through the threaded hole in the card seat II (21), and the screw rod (27) and the threaded hole of the card seat II (21) are engaged with each other by a thread. The outer end of the horizontal static sounding rod (25) is fixedly connected to the card seat II (21), and the inner end of the horizontal static sounding rod (25) is a free end. A socket is provided in the card seat III (22), and the inner end of the horizontal static sounding rod (25) passes through the socket of the card seat III (22).

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