Standard Penetration Test Effective Hammer Energy Testing System

Abstract

This invention discloses a standard penetration test effective hammer energy testing system, comprising a standard penetrator and a standard penetration effective energy testing unit directly connected to its upper end. The unit consists of a coaxially arranged upper connecting part, a lower connecting part, and a sealed protective sleeve forming a closed cavity. An annular stress acquisition unit is installed inside the cavity, and an acceleration acquisition unit is installed at the bottom of the lower connecting part. A communication probe is threaded to the upper connecting part at its lower end, and a standard penetration hammer unit and a wireless communication module are installed at its top. During testing, the hammer energy is transmitted to the testing unit through the probe. The annular stress acquisition unit and the acceleration acquisition unit simultaneously acquire stress and acceleration data, which are transmitted through the probe to the wireless module. Finally, the data acquisition unit calculates the accurate hammer energy. This invention effectively solves the problem of data distortion in external testing by directly testing the energy acting on the penetrator, significantly improving the testing depth and accuracy of the standard penetration test.

Description

Technical Field

[0001] This utility model belongs to the field of standard penetration test technology, and in particular relates to a standard penetration test effective hammer impact energy testing system. Background Technology

[0002] The Standard Penetration Test (SPT) is a widely used in-situ geotechnical engineering testing technique both domestically and internationally. It involves dropping a 63.5 kg hammer freely from a specified drop distance (76 cm) to drive a standard-sized split-tube penetrator into the soil. The soil properties are determined by the number of blows required to penetrate 30 cm. The SPT is suitable for cohesive soils, silt, sandy soils, residual soils, and completely weathered or partially strongly weathered rock formations. It is widely used to obtain physical and mechanical properties of soils such as density, state, strength, and deformation parameters; to determine the bearing capacity and settlement prediction of shallow foundations; to evaluate soil liquefaction; to classify and classify soil strata; to determine the bearing capacity and subgrade coefficient of pile foundations; to test pile foundations and evaluate the quality of composite foundations; and in engineering testing. The SPT has advantages such as simple operation, ease of use, low cost, wide applicability to different soil types, and abundant engineering test data and experience. However, due to the energy dissipation of the hammer blows, rod length correction is usually required to ensure consistency of test results at different depths. The standard penetration test (SPT) rod length correction in the "Code for In-situ Testing of Railway Engineering Geology" is usually only applicable to soil within a depth of 21m, which is shallow. The hammer blow count N value is greatly affected by various factors such as the drop hammer system, rod length, rod diameter, and overlying soil pressure, making it difficult to guarantee the consistency of test results.

[0003] In recent years, the testing of standard penetration test hammer impact energy has gradually become a research hotspot. James Fisher and Sons plc in the UK and PDI in the US have both developed standard penetration energy analyzers. By adding acceleration and strain sensors under the hammer pad of the standard penetration tester at the orifice, the hammer impact energy of the standard penetration test is measured, and then the impact number N value obtained by different standard penetration test equipment is corrected based on the measured energy. However, the above equipment still measures the energy transmitted from the standard penetration hammer to the probe rather than the energy directly acting on the standard penetration tester, and the problem of rod length correction still cannot be avoided. Utility Model Content

[0004] To address the problems existing in the prior art, this utility model provides a standard penetration test effective hammer impact energy testing system.

[0005] This invention is implemented as follows: a standard penetration test effective hammer impact energy testing system, characterized by comprising: a standard penetrator; a standard penetration effective energy testing unit, directly connected to the upper end of the standard penetrator, including an upper connecting part, a lower connecting part, and a sealing sleeve coaxially arranged, the sealing sleeve sealingly connecting the upper connecting part and the lower connecting part to form a sealed cavity, the cavity being provided with an annular stress acquisition unit, and the bottom end of the lower connecting part being provided with an acceleration acquisition unit; a communication probe, the lower end of which is threadedly connected to the upper connecting part; a standard penetration hammer impact unit, disposed at the top of the communication probe; a wireless communication module, disposed at the top of the communication probe; and a data acquisition and analysis display unit; wherein, the detection signals of the annular stress acquisition unit and the acceleration acquisition unit are transmitted to the wireless communication module via the communication probe, and then sent by the wireless communication module to the data acquisition and analysis display unit for hammer impact energy calculation.

[0006] In a further preferred embodiment, the sealing sleeve is connected to the upper connecting part and the lower connecting part by a threaded sealing sleeve, and the annular stress acquisition unit is an annular stress sensor that is circumferentially attached to the inner wall of the sealed cavity.

[0007] More preferably, the acceleration acquisition unit is threadedly mounted in the sensor mounting base at the bottom of the lower connecting part.

[0008] More preferably, the acceleration acquisition unit includes at least one impact-type acceleration sensor.

[0009] More preferably, the range of the impact-type accelerometer is 10000g.

[0010] More preferably, the wireless communication module is integrated into a sealed compartment at the top of the communication probe.

[0011] More preferably, the standard penetration hammer unit includes: a hammer pad, disposed at the top of the communication probe; a core hammer with a mass of 63.5 kg; and a hammer lifting and automatic hammer dropping assembly, used to automatically release the core hammer after lifting it to a height of 76 cm.

[0012] The advantages and technical effects of this invention are as follows: This system, through a structured integrated design, achieves precise testing of the hammer impact energy in the standard penetration test (SPT). The combination of a sealed cavity and highly protected sensors solves the industry problem of data interference in field environments; the circumferential stress acquisition and multi-accelerometer collaboration overcome the accuracy bottleneck of traditional single-point testing; and the application of wireless communication and automated hammer impact components significantly improves testing efficiency and data real-time performance. The system combines standardization and adaptability, and can be widely applied in fields such as geotechnical engineering investigation and foundation treatment effect evaluation, providing quantitative basis for engineering decision-making. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the standard penetration effective energy test unit structure of this utility model.

[0015] In the diagram: 1. Standard penetrator; 2. Standard penetration effective energy testing unit; 2-1. Upper connecting part; 2-2. Circular stress acquisition unit; 2-3. Acceleration acquisition unit; 2-4. Lower connecting part; 2-5. Sealing sleeve; 3. Communication probe; 4. Standard penetration hammer unit; 4-1. Hammer pad; 4-2. Through hammer; 4-3. Hammer lifting and automatic hammer dropping assembly; 5. Wireless communication module; 6. Data acquisition and analysis display unit. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model.

[0017] A standard penetration test effective hammer impact energy testing system includes:

[0018] Standard penetrator 1; as the terminal component for energy transfer, it directly penetrates the formation under the action of hammer energy to conduct standard penetration tests.

[0019] The standard penetration effective energy testing unit 2 is directly connected to the upper end of the standard penetrator 1. It includes an upper connecting part 2-1, a lower connecting part 2-4, and a sealing sleeve 2-5 arranged coaxially. The sealing sleeve 2-5 seals the upper connecting part 2-1 and the lower connecting part 2-4 to form a sealed cavity. The sealed cavity design can isolate external interference factors such as mud and moisture, ensuring the stability of sensor signal acquisition. The cavity is equipped with a ring stress acquisition unit 2-2; the ring layout can cover 360°, accurately testing the impact force transmitted to the standard penetrator, avoiding measurement deviations caused by the installation angle of the unidirectional sensor. The bottom end of the lower connecting part 2-4 is equipped with an acceleration acquisition unit 2-3; the bottom end is close to the standard penetrator, which can accurately capture the impact acceleration at the moment of hammering, reducing the impact of energy transfer loss on the data.

[0020] The lower end of the communication probe 3 is threadedly connected to the upper connecting part 2-1; the threaded connection method ensures quick assembly and disassembly of the test unit and the probe, adapting to different depth test requirements.

[0021] The standard penetration hammer unit 4 is located at the top of the communication probe 3; as an energy input source, it provides standardized hammering action to ensure test repeatability.

[0022] The wireless communication module 5 is located at the top of the communication probe 3; the top position is far away from the hammer vibration source to reduce electromagnetic interference and ensure the reliability of data transmission.

[0023] Data acquisition and analysis display unit 6; integrated algorithm can display stress and acceleration time history data in real time, automatically calculate hammer impact energy, and reduce manual calculation errors.

[0024] The detection signals from the annular stress acquisition unit 2-2 and the acceleration acquisition unit 2-3 are transmitted to the wireless communication module 5 via the communication probe 3, and then sent by the wireless communication module 5 to the data acquisition and analysis display unit 6 for hammering energy calculation.

[0025] Preferably, the sealing sleeve 2-5 is connected to the upper connecting part 2-1 and the lower connecting part 2-4 by a threaded sealing sleeve; the threaded sealing sleeve takes into account both connection strength and sealing performance, and is suitable for long-term use in complex outdoor environments. The annular stress acquisition unit 2-2 is an annular stress sensor, which is circumferentially attached to the inner wall of the sealed cavity; circumferential attachment can uniformly sense axial stress and improve the measurement accuracy under complex stress conditions.

[0026] More preferably, the acceleration acquisition unit 2-3 is threadedly mounted in the sensor mounting base at the bottom of the lower connecting part 2-4; the threaded mounting facilitates sensor replacement and calibration, reducing maintenance costs.

[0027] More preferably, the acceleration acquisition unit 2-3 includes at least one impact-type acceleration sensor; the multi-sensor layout can cross-verify data and avoid single-point failure.

[0028] More preferably, the range of the impact-type accelerometer is 10000g; the high range design can cover the extreme acceleration generated by the hammer impact in the standard penetration test, and prevent sensor overload distortion.

[0029] Preferably, the wireless communication module 5 is integrated into the sealed chamber at the top of the communication probe 3; the sealed chamber has an IP67 protection rating, which is suitable for data transmission in rainy or muddy environments.

[0030] More preferably, the standard penetration hammer unit 4 includes:

[0031] Hammer pad 4-1 is located at the top of the communication probe 3. The penetration hammer 4-2 weighs 63.5 kg and conforms to international standard penetration test specifications (such as ASTM D1586), ensuring the comparability of test results. The hammer lifting and automatic drop assembly 4-3 is used to automatically release the penetration hammer 4-2 after lifting it to a height of 76 cm; the automated design eliminates human error and improves the accuracy of hammer height and drop distance.

[0032] Working principle

[0033] At the start of the test, the hammer lifting and automatic hammer dropping assembly raises the penetrating hammer to a height of 76cm and then releases it. The hammer falls freely and impacts the hammer pad, generating standardized impact energy. This energy is transmitted via the communication probe to the standard penetration effective energy testing unit. Simultaneously, the annular stress acquisition unit senses stress changes in real time, and the acceleration acquisition unit records the impact acceleration time history changes at the connection point. The detection signal is transmitted via internal wires of the communication probe to the wireless communication module at the top. The module encrypts the raw data and wirelessly transmits it to the data acquisition and analysis display unit. The analysis unit uses a preset algorithm (such as the energy integration method) to fuse and calculate the stress and acceleration time history data, ultimately outputting precise values ​​for dynamic penetration resistance and hammer impact energy, and simultaneously generating test curves and reports.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A standard penetration test effective hammer energy testing system, characterized by, include: Standard penetrator (1); The standard penetration effective energy test unit (2) is directly connected to the upper end of the standard penetrator (1). It includes an upper connecting part (2-1), a lower connecting part (2-4), and a sealing sleeve (2-5) arranged coaxially. The sealing sleeve (2-5) seals the upper connecting part (2-1) and the lower connecting part (2-4) to form a closed cavity. The cavity is provided with an annular stress acquisition unit (2-2), and the bottom end of the lower connecting part (2-4) is provided with an acceleration acquisition unit (2-3). The lower end of the communication probe (3) is threadedly connected to the upper connecting part (2-1); A standard penetration hammer unit (4) is installed on the top of the communication probe (3); A wireless communication module (5) is disposed at the top of the communication probe (3); Data acquisition and analysis display unit (6); The detection signals of the annular stress acquisition unit (2-2) and the acceleration acquisition unit (2-3) are transmitted to the wireless communication module (5) via the communication probe (3), and then sent by the wireless communication module (5) to the data acquisition and analysis display unit (6) for hammer energy calculation.

2. The standard penetration test effective hammer energy testing system of claim 1, wherein: The sealing sleeve (2-5) is connected to the upper connecting part (2-1) and the lower connecting part (2-4) by a threaded sealing sleeve. The annular stress acquisition unit (2-2) is an annular stress sensor, which is circumferentially attached to the inner wall of the sealed cavity.

3. The standard penetration test effective hammer energy testing system according to claim 1 or 2, wherein: The acceleration acquisition unit (2-3) is threadedly installed in the sensor mounting base at the bottom of the lower connecting part (2-4).

4. The standard penetration test effective hammer energy testing system of claim 1, wherein: The acceleration acquisition unit (2-3) includes at least one impact-type acceleration sensor.

5. The standard penetration test effective hammer energy testing system of claim 4, wherein: The impact-type accelerometer has a range of 10000g.

6. The standard penetration test effective hammer energy testing system of claim 1, wherein: The wireless communication module (5) is integrated into the sealed chamber at the top of the communication probe (3).

7. The standard penetration test effective hammer energy testing system of claim 1, wherein: The standard penetration hammer unit (4) includes: Hammer pad (4-1) is placed at the top of the communication probe (3); The hammer (4-2) has a mass of 63.5 kg. The hammer lifting and automatic hammer dropping assembly (4-3) is used to lift the through hammer (4-2) to a height of 76cm and then release it automatically.

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