A testing device and method for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading.

Abstract

This invention discloses a testing device and method for the dynamic compression modulus and damping ratio of soil under cyclic loading of seismic compressive waves, belonging to the field of geotechnical testing technology. The device includes a platform; a loading mechanism mounted on the platform for applying dynamic loads to the sample; a fixing mechanism mounted on the loading mechanism for fixing the sample; a drainage mechanism mounted on the fixing mechanism for draining internal water during the application of counterpressure and saturation of the sample; and a computer connected to both the loading and drainage mechanisms for controlling their operation. By combining cyclic lateral compression with a piezoelectric ceramic oscillator to test the dynamic lateral compression modulus of soil, this invention overcomes the current lack of laboratory methods for testing the dynamic properties of soil caused by vertical seismic motion.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical testing technology, specifically relating to a testing device and method for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading. Background Technology

[0002] During an earthquake, the site effect of surface soil significantly influences the propagation characteristics of seismic waves, thereby exacerbating the amplification effect of ground motion and causing greater structural damage. Previous earthquake observations have shown that the amplification effect of seismic waves is closely related to the nonlinear behavior of soil. In particular, the nonlinear response of soil under strong earthquakes is one of the important factors inducing the site effect.

[0003] Existing research largely focuses on the nonlinear behavior of soil under shear wave (S-wave) loading, particularly the nonlinear changes in shear modulus and damping ratio. These studies provide theoretical support for understanding the mechanical behavior of soil under seismic loading and have been widely applied to site response analysis. However, actual seismic waves include not only horizontal shear waves but also vertical compression waves (P-waves). The impact of vertical ground motion on structures and soil layers is often overlooked, but existing research has shown that vertical ground motion plays a crucial role in inducing structural failure and ground instability.

[0004] In the study of nonlinear behavior of soil, laboratory testing is a common method for obtaining nonlinear modulus and damping ratio related to shear. However, due to the lack of specialized experimental equipment, experimental studies on the dynamic properties of soil under compression wave action are relatively few, and relevant experimental data are scarce.

[0005] Based on the above, and considering that existing technologies and testing methods cannot test the dynamic properties of soil under cyclic compression wave loading, this invention aims to provide an apparatus and method capable of testing the lateral confined compression modulus and damping ratio of soil across the entire strain range. Summary of the Invention

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A testing device for the dynamic compression modulus and damping ratio of soil under cyclic loading of seismic compression waves, comprising:

[0008] platform;

[0009] A loading mechanism, which is disposed on the support platform, is used to apply a dynamic load to the sample;

[0010] A fixing mechanism is provided on the loading mechanism for fixing the sample;

[0011] A drainage mechanism, which is mounted on the fixing mechanism, is used to drain internal water during the application of back pressure and saturation of the sample.

[0012] A computer is connected to the loading mechanism and the drainage mechanism respectively, and is used to control the operation of the loading mechanism and the drainage mechanism.

[0013] Furthermore, the loading mechanism includes a lifting platform, a loading cap, a horn sleeve, a piston screw rod, a loading frame, and a displacement sensor;

[0014] The lifting platform is mounted on the support platform, and a base is provided at the end of the lifting platform away from the support platform; the fixing mechanism is mounted on the base.

[0015] The displacement sensor is located on the side of the base away from the fixing mechanism;

[0016] The loading frame is connected to the support platform via a connecting screw and is located above the base;

[0017] The loading cap is connected to one end of the piston screw rod, and the other end of the piston screw rod is connected to the loading frame by a fixing bolt; wherein, the loading cap is located directly above the base, and a vertical pressure sensor is also provided inside the loading cap;

[0018] The horn sleeve is connected to the fixing mechanism and is located directly below the loading cap;

[0019] The lifting platform, the displacement sensor, and the vertical pressure sensor are connected to the computer.

[0020] Furthermore, the fixing mechanism includes a sample base, a sample cap, and a rigid mold;

[0021] The sample base is disposed on top of the base, the sample is disposed on top of the sample base, and the sample cap is disposed on top of the sample; the side of the sample cap away from the sample is connected to the horn sleeve.

[0022] The rigid mold is fitted over the sample base, the sample, and the sample cap.

[0023] Furthermore, a permeable stone is provided between the sample, the sample base, and the sample cap.

[0024] Furthermore, a rubber membrane is fitted over the sample base, the sample, and the sample cap; the rigid mold is fitted over the rubber membrane, and rubber rings are provided between the two ends of the rubber membrane and the rigid mold.

[0025] Furthermore, the rigid mold consists of two split rigid molds, each with a semi-circular cross-section, used to limit the lateral deformation of the sample.

[0026] Furthermore, a piezoelectric ceramic oscillator is also provided in the sample cap and the sample base, and the piezoelectric ceramic oscillator is connected to the computer.

[0027] Furthermore, the drainage mechanism includes a water pipe, an inlet pipe, and an outlet pipe;

[0028] The sample base is provided with a back pressure inlet / outlet and a water inlet; the back pressure inlet / outlet passes through the rigid mold and is connected to the first end of the water pipe, and the second end of the water pipe is disposed on the support platform; the second end of the water pipe is also provided with a first valve and a pore pressure sensor; the water inlet passes through the rigid mold and is connected to the first end of the water inlet pipe, and the second end of the water inlet pipe is disposed on the support platform; the second end of the water inlet pipe is also provided with a third valve;

[0029] The sample cap is provided with a water outlet; the water outlet is connected to the first end of the water outlet pipe, the second end of the water outlet pipe is provided on the support platform, and the second end of the water outlet pipe is also provided with a second valve;

[0030] The first valve, the second valve, the third valve, and the pore pressure sensor are all connected to the computer.

[0031] A testing method for a testing device for the dynamic compression modulus and damping ratio of soil under cyclic seismic compression wave loading as described above includes the following steps:

[0032] S1. Install the sample onto the sample base, secure the sample with a rigid mold, install the sample cap, and install the loading frame.

[0033] S2. Open the switch of the first valve and test the sealing performance of the rubber diaphragm according to the set back pressure;

[0034] S3. After the sealing test, close the first valve and apply a certain vertical stress; open the second and third valves to saturate the sample with water head.

[0035] S4. After the water head is saturated, close the second and third valves, open the first valve, and use the loading mechanism to saturate the sample with back pressure.

[0036] S5. After the back pressure saturation is completed, the specimen is loaded with the set vertical stress to begin consolidation;

[0037] S6. After consolidation, the dynamic compression modulus and damping ratio of the soil under seismic compression wave cyclic loading are calculated, and full strain range tests are performed.

[0038] Furthermore, the calculation method for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading in step S6 includes the following steps:

[0039] S10, the specimen reaches the target vertical stress. Subsequently, an excitation signal was generated using the transmitter to conduct a piezoelectric ceramic oscillator test, and the compression wave velocity V was measured. p Calculate the small strain confined compressive modulus M0 of the specimen;

[0040] M0 = V p 2 ρ

[0041] Where ρ is the density of the sample;

[0042] S20. Reconsolidate the sample after the piezoelectric ceramic crystal oscillator test, apply vertical stress to the target vertical stress, and apply dynamic load.

[0043] S30. Apply a dynamic load to the specimen by lifting the specimen base using a lifting platform, and record the vertical stress σ during the dynamic load process using a vertical pressure sensor. V The displacement sensor records the vertical strain ε V The vertical stress-strain curve is obtained:

[0044] Lateral confined compressive modulus M of the specimen under compression path C :

[0045] Lateral confined compressive modulus M of the specimen under tensile path E :

[0046] Damping ratio λ:

[0047] in, Vertical stress for compressing the target strain along the path; The vertical stress of the target strain along the stretching path; W D The area of ​​the hysteresis loop; W S Area of ​​the polygon;

[0048] S40. After the dynamic load is completed, the specimen is reconsolidated and the next level of strain dynamic load test is carried out.

[0049] Beneficial effects:

[0050] 1. This invention uses a combination of cyclic lateral compression and piezoelectric ceramic crystal oscillator to test the lateral compression modulus of soil, overcoming the current lack of research on the use of laboratory methods to test the vertical seismic dynamic characteristics of soil, while laboratory testing is the most commonly used method to obtain the shear modulus, nonlinear modulus and damping ratio.

[0051] 2. The dynamic load for the lateral compression test can measure soil strain within a range of 10. -4 ~10 -2 The testable range of piezoelectric ceramic crystal oscillators can reach 10. -6 Therefore, combining piezoelectric ceramic crystal oscillators with lateral compression tests can expand the range of soil strain that instruments can measure.

[0052] 3. Based on the asymmetry of the vertical stress-strain curve, a method is provided to calculate the lateral confined compressive modulus and damping ratio under compression and tension paths, respectively. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the structure of a testing device for the dynamic compression modulus and damping ratio of soil under cyclic loading of seismic compression waves according to the present invention.

[0054] Figure 2 This is a schematic diagram of the fixing mechanism of the present invention;

[0055] Figure 3 This is a schematic diagram of the rigid mold of the present invention;

[0056] Figure 4 This is a schematic diagram illustrating the calculation of the confined compression modulus of the present invention;

[0057] Explanation of reference numerals in the attached drawings: 1-Lifting platform, 2-Displacement sensor, 3-First valve, 4-Second valve, 5-Orifice pressure sensor, 6-Water pipe, 7-Back pressure inlet / outlet, 8-Sample base, 9-Rubber diaphragm, 10-Sample, 11-Permeable stone, 12-Sample cap, 13-Outlet, 14-Sounder sleeve, 15-Loading cap, 16-Vertical pressure sensor, 17-Loading frame, 18-Fixing bolt, 19-Piston screw rod, 20-Vertical pressure sensor signal line, 21-Connecting screw rod, 22-Piezoelectric ceramic crystal oscillator signal line, 23-Rubber ring, 24-Piezoelectric ceramic crystal oscillator, 25-Rigid mold, 26-Inlet, 27-Base, 28-Third valve, 29-Support platform. Detailed Implementation

[0058] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0059] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0060] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0061] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0062] Example 1

[0063] refer to Figures 1-3 A testing device for the dynamic compression modulus and damping ratio of soil under cyclic loading of seismic compression waves, comprising:

[0064] Platform 29;

[0065] The loading mechanism is mounted on the support 29 and is used to apply dynamic load to the specimen 10.

[0066] A fixing mechanism is provided on the loading mechanism and is used to fix the sample 10.

[0067] The drainage mechanism is installed on the fixed mechanism and is used to drain the internal water during the application of back pressure and saturation of the sample.

[0068] The computer is connected to both the loading mechanism and the drainage mechanism to control their operation.

[0069] Preferably, the loading mechanism includes a lifting platform 1, a loading cap 15, a horn sleeve 14, a piston screw rod 19, a loading frame 17, and a displacement sensor 2;

[0070] The lifting platform 1 is mounted on the support platform 29, and a base 27 is provided at the end of the lifting platform 1 away from the support platform 29; the fixing mechanism is mounted on the base 27.

[0071] The displacement sensor 2 is located on the side of the base 27 away from the fixing mechanism;

[0072] The loading frame 17 is connected to the support platform 29 via the connecting screw rod 21 and is located above the base 27;

[0073] The loading cap 15 is connected to one end of the piston screw rod 19, and the other end of the piston screw rod 19 is connected to the loading frame 17 by a fixing bolt 18; wherein, the loading cap 15 is located directly above the base 27, and a vertical pressure sensor 16 is also provided inside the loading cap 15;

[0074] The horn sleeve 14 is connected to the fixing mechanism and is located directly below the loading cap 15;

[0075] The lifting platform 1, displacement sensor 2, and vertical pressure sensor 16 are connected to the computer.

[0076] In this embodiment, the vertical pressure sensor 16 is connected to the computer via the vertical pressure sensor signal line 20.

[0077] Preferably, the fixing mechanism includes a sample base 8, a sample cap 12, and a rigid mold 25;

[0078] The sample base 8 is set on top of the base 27, the sample 10 is set on top of the sample base 8, and the sample cap 12 is set on top of the sample 10; the side of the sample cap 12 away from the sample 10 is connected to the horn sleeve 14.

[0079] The rigid mold 25 is fitted around the sample base 8, sample 10 and sample cap 12.

[0080] Preferably, a permeable stone is provided between the sample 10, the sample base 8, and the sample cap 12.

[0081] Preferably, a rubber membrane 9 is fitted over the sample base 8, sample 10 and sample cap 12; a rigid mold 25 is fitted over the rubber membrane 9, and rubber rings 23 are provided between the two ends of the rubber membrane 9 and the rigid mold 25.

[0082] In this embodiment, the rubber membrane 9, the sample base 8, and the sample cap 12 form a sealed space, which seals the sample 10 within the sealed space.

[0083] In this embodiment, the rigid mold 25 and the rubber membrane 9 are connected to the base 27 by screws.

[0084] Preferably, the rigid mold 25 is composed of two split rigid molds with a semi-circular cross-section, which are used to limit the lateral deformation of the sample 10.

[0085] In this embodiment, the rigid mold 25 is fastened to the base 27 by bolts to ensure that the rigid mold does not move during the cyclic loading process.

[0086] In this embodiment, the bottom wall thickness of the split rigid mold is less than the top wall thickness, and the rubber ring 23 used to fasten the sample base 8 is placed there; the rubber ring 23 at the bottom of the rubber membrane 9 is located between the rubber membrane 9 and the split rigid mold, and the rubber ring 23 at the top of the rubber membrane 9 is located at the top of the split rigid mold.

[0087] In this embodiment, the two split rigid molds are completely fitted to the rubber membrane 9, completely enclosing the rubber membrane 9; preferably, the two split rigid molds are clamped by wire locks, thereby limiting the lateral deformation of the sample 10.

[0088] Preferably, the sample cap 12 and the sample base 8 are further provided with a piezoelectric ceramic crystal oscillator 24, which is connected to the computer.

[0089] In this embodiment, the piezoelectric ceramic oscillator 24 is connected to the computer via the piezoelectric ceramic oscillator signal line 22.

[0090] Preferably, the drainage mechanism includes a water pipe 6, an inlet pipe, and an outlet pipe;

[0091] The sample base 8 has a back pressure inlet / outlet 7 and an inlet 26; the back pressure inlet / outlet 7 passes through the rigid mold 25 and is connected to the first end of the water pipe 6, and the second end of the water pipe 6 is set on the support 29; the second end of the water pipe 6 is also equipped with a first valve 3 and a pore pressure sensor 5; the inlet 26 passes through the rigid mold 25 and is connected to the first end of the inlet pipe, and the second end of the inlet pipe is set on the support 29; the second end of the inlet pipe is also equipped with a third valve 28;

[0092] The sample cap 12 has a water outlet; the water outlet is connected to the first end of the water outlet pipe, the second end of the water outlet pipe is set on the support 29, and the second end of the water outlet pipe is also equipped with a second valve 4.

[0093] Among them, the first valve 3, the second valve 4, the third valve 28, and the pore pressure sensor 5 are connected to the computer.

[0094] In this embodiment, the bottom of the rigid mold 25 is provided with two through holes, through which the water inlet and the back pressure inlet / outlet 7 pass respectively.

[0095] Example 2

[0096] A testing method for a testing device for soil dynamic compression modulus and damping ratio under seismic compression wave cyclic loading as described in Example 1 includes the following steps:

[0097] S1. Install the sample onto the sample base, secure the sample with a rigid mold, install the sample cap, and install the loading frame.

[0098] S2. Open the switch of the first valve and test the sealing performance of the rubber diaphragm according to the set back pressure;

[0099] S3. After the sealing test, close the first valve and apply a certain vertical stress; open the second and third valves to saturate the sample with water head.

[0100] S4. After the water head is saturated, close the second and third valves, open the first valve, and use the loading mechanism to saturate the sample with back pressure.

[0101] S5. After the back pressure saturation is completed, the specimen is loaded with the set vertical stress to begin consolidation;

[0102] S6. After consolidation, the dynamic compression modulus and damping ratio of the soil under seismic compression wave cyclic loading are calculated, and full strain range tests are performed.

[0103] In this embodiment, a back pressure controller is also included, which is connected to the drainage mechanism, the fixing mechanism, and the loading mechanism.

[0104] In this embodiment, step S6 includes the following steps:

[0105] During the loading process, the back pressure controller maintains the drainage condition loading, allowing the specimen to deform vertically;

[0106] The loading mechanism performs cyclic loading by setting a target strain. The cyclic loading stage includes compression and tension stages. In the tension stage, the vertical stress corresponding to the target strain is not less than 20% of the consolidation vertical stress. After each strain loading stage, the specimen is reconsolidated before the next strain loading stage is performed.

[0107] The displacement sensor and vertical pressure sensor transmit the detected data to the computer, recording the vertical stress and vertical strain of the sample during the test process.

[0108] Example 3

[0109] refer to Figure 4 This embodiment describes the calculation method for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading in step S6 of embodiment 2, including the following steps:

[0110] S10, the specimen reaches the target vertical stress. Subsequently, an excitation signal was generated using the transmitter to conduct a piezoelectric ceramic oscillator test, and the compression wave velocity V was measured. p Calculate the small strain confined compressive modulus M0 of the specimen;

[0111] M0 = V p 2 ρ

[0112] Where ρ is the density of the sample;

[0113] S20. Reconsolidate the sample after the piezoelectric ceramic crystal oscillator test, apply vertical stress to the target vertical stress, and apply dynamic load.

[0114] S30. Apply a dynamic load to the specimen by lifting the specimen base using a lifting platform, and record the vertical stress ε during the dynamic load process using a vertical pressure sensor. V The displacement sensor records the vertical strain ε V The vertical stress-strain curve is obtained:

[0115] Lateral confined compressive modulus M of the specimen under compression path C :

[0116] Lateral confined compressive modulus M of the specimen under tensile path E :

[0117] Damping ratio λ:

[0118] in, Vertical stress for compressing the target strain along the path; The vertical stress of the target strain along the stretching path; W D The area of ​​the hysteresis loop; W S Area of ​​the polygon;

[0119] S40. After the dynamic load is completed, the specimen is reconsolidated and the next level of strain dynamic load test is carried out.

[0120] In this embodiment, after reconsolidation for 5 minutes, a dynamic load test for the next level of target strain is conducted.

[0121] This invention enables the direct conduct of subsequent cyclic lateral compression tests on the same sample after conducting piezoelectric ceramic oscillator tests. This effectively simulates the lateral compression modulus and damping ratio of soil under compression wave load over a wide strain range, overcoming the limitations of existing testing devices that cannot test the dynamic modulus and damping ratio of soil under compression wave load.

[0122] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for testing the dynamic compression modulus and damping ratio of soil under cyclic loading of seismic compression waves, characterized in that, Includes the following steps: S1. Install the sample onto the sample base, secure the sample with a rigid mold, install the sample cap, and install the loading frame. S2. Open the switch of the first valve and test the sealing performance of the rubber diaphragm according to the set back pressure; S3. After the sealing test, close the first valve and apply a certain vertical stress; open the second and third valves to saturate the sample with water head. S4. After the water head is saturated, close the second and third valves, open the first valve, and use the loading mechanism to saturate the sample with back pressure. S5. After the back pressure saturation is completed, the specimen is loaded with the set vertical stress to begin consolidation; S6. After consolidation, the dynamic compression modulus and damping ratio of the soil under seismic compression wave cyclic loading are calculated, and full strain range tests are conducted. The calculation method for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading in step S6 includes the following steps: S10, The specimen reaches the target vertical stress. Subsequently, an excitation signal was generated using the transmitter to conduct a piezoelectric ceramic oscillator test and measure the compression wave velocity. Calculate the small strain confined compressive modulus of the specimen. ; Where ρ is the density of the sample; S20. Reconsolidate the sample after the piezoelectric ceramic crystal oscillator test, apply vertical stress to the target vertical stress, and apply dynamic load. S30. Apply a dynamic load to the specimen by lifting the specimen base using a lifting platform, and record the vertical stress during the dynamic load process using a vertical pressure sensor. Displacement sensors record vertical strain The vertical stress-strain curve is obtained; based on the asymmetry of the vertical stress-strain curve, a method is provided to calculate the lower confined compression modulus and damping ratio under compression and tension paths respectively. Lateral confined compressive modulus of the specimen under compression path : Laterally confined compressive modulus of specimen under tensile path : Damping ratio λ: in, Vertical stress for compressing the target strain along the path; Vertical stress is the target strain along the stretching path. The area of ​​the hysteresis loop; Area of ​​the polygon; S40. After the dynamic load is completed, the specimen is reconsolidated and the next level of strain dynamic load test is carried out.

2. A testing device for the dynamic compression modulus and damping ratio of soil under cyclic loading of seismic compressive waves, used to implement the testing method for the dynamic compression modulus and damping ratio of soil under cyclic loading of seismic compressive waves as described in claim 1, characterized in that... include: platform; A loading mechanism, which is disposed on the support platform, is used to apply a dynamic load to the sample; A fixing mechanism is provided on the loading mechanism for fixing the sample; A drainage mechanism, which is mounted on the fixing mechanism, is used to drain internal water during the application of back pressure and saturation of the sample. A computer is connected to the loading mechanism and the drainage mechanism respectively, and is used to control the operation of the loading mechanism and the drainage mechanism.

3. The testing device for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading according to claim 2, characterized in that, The loading mechanism includes a lifting platform, a loading cap, a horn sleeve, a piston screw rod, a loading frame, and a displacement sensor; The lifting platform is mounted on the support platform, and a base is provided at the end of the lifting platform away from the support platform; the fixing mechanism is mounted on the base. The displacement sensor is located on the side of the base away from the fixing mechanism; The loading frame is connected to the support platform via a connecting screw and is located above the base; The loading cap is connected to one end of the piston screw rod, and the other end of the piston screw rod is connected to the loading frame by a fixing bolt; wherein, the loading cap is located directly above the base, and a vertical pressure sensor is also provided inside the loading cap; The horn sleeve is connected to the fixing mechanism and is located directly below the loading cap; The lifting platform, the displacement sensor, and the vertical pressure sensor are connected to the computer.

4. The testing device for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading as described in claim 3, characterized in that, The fixing mechanism includes a sample base, a sample cap, and a rigid mold; The sample base is disposed on top of the base, the sample is disposed on top of the sample base, and the sample cap is disposed on top of the sample; the side of the sample cap away from the sample is connected to the horn sleeve. The rigid mold is fitted over the sample base, the sample, and the sample cap.

5. The testing device for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading according to claim 4, characterized in that, A permeable stone is provided between the sample, the sample base, and the sample cap.

6. The testing device for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading according to claim 4, characterized in that, A rubber membrane is fitted over the sample base, the sample, and the sample cap; a rigid mold is fitted over the rubber membrane, and rubber rings are provided between the two ends of the rubber membrane and the rigid mold.

7. The testing device for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading according to claim 6, characterized in that, The rigid mold consists of two split rigid molds, each with a semi-circular cross-section, used to limit the lateral deformation of the sample.

8. The testing device for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading according to claim 4, characterized in that, The sample cap and the sample base are also provided with a piezoelectric ceramic oscillator, which is connected to the computer.

9. The testing device for the dynamic compression modulus and damping ratio of soil under seismic compression wave cyclic loading according to claim 4, characterized in that, The drainage mechanism includes a water pipe, an inlet pipe, and an outlet pipe; The sample base is provided with a back pressure inlet / outlet and a water inlet; the back pressure inlet / outlet passes through the rigid mold and is connected to the first end of the water pipe, and the second end of the water pipe is disposed on the support platform; the second end of the water pipe is also provided with a first valve and a pore pressure sensor; the water inlet passes through the rigid mold and is connected to the first end of the water inlet pipe, and the second end of the water inlet pipe is disposed on the support platform; the second end of the water inlet pipe is also provided with a third valve; The sample cap is provided with a water outlet; the water outlet is connected to the first end of the water outlet pipe, the second end of the water outlet pipe is provided on the support platform, and the second end of the water outlet pipe is also provided with a second valve; The first valve, the second valve, the third valve, and the pore pressure sensor are all connected to the computer.

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