Seismic Soil Probe Hammer Mechanism for Signal Coupling
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Solution Overview
Problem
Seismic cone penetration testing (SCPT) devices are time-consuming and expensive, especially in offshore applications, due to coupling issues and reduced accuracy with depth, as seismic wave signals are dampened and their trajectory becomes uncertain, necessitating a more efficient method for continuous sensing and signal generation.
Innovation Solution
A seismic soil probe with an integrated seismic sensor and generator, utilizing a mechanical biasing member like a spring-loaded hammer actuated by a cam and stepper motor to generate consistent, high-impact seismic waves, allowing for continuous testing without surface-based seismic sources and minimizing signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate seismic source is installed on the seabed for SCPT testing, then seismic wave generation is achieved, but coupling issues occur leading to poor signal transmission
Solution Approach 1:
The patent combines the seismic source and sensor into a single integrated probe unit that is inserted directly into the soil. The seismic hammer mechanism is housed within the probe body, eliminating the need for separate seabed installation and improving coupling with the soil medium.
Solution Approach 2:
The probe body acts as an intermediary medium that directly couples the generated seismic waves to the soil. By integrating the source within the probe and using the probe body itself as the transmission medium, the system achieves better coupling compared to separate seabed sources.
2Measurement precision
If the cone penetrometer is driven into the soil intermittently to different depths, then testing at various depths is achieved, but the overall testing time becomes relatively lengthy
Solution Approach 1:
The integrated probe allows for continuous driving into the soil while performing seismic testing at multiple depths. The system can continuously generate and detect seismic waves during the driving process, eliminating the need to stop and restart at different depth intervals.
Solution Approach 2:
The probe is pre-configured with both the seismic source and sensor, allowing testing to begin immediately upon insertion. The integrated design enables measurements to be taken continuously as the probe advances, rather than requiring preliminary setup at each depth level.
3Ease of operation
If the rod forming the cone penetrometer is made narrow to facilitate insertion, then ease of insertion is improved, but space for housing a seismic generator becomes limited
Solution Approach 1:
The seismic hammer mechanism and other components are nested within the probe body in a space-efficient arrangement. The hammer, biasing member, and actuator are compactly integrated, allowing the generator to fit within the narrow rod structure.
Solution Approach 2:
The seismic generator uses a dynamic hammer mechanism that requires minimal static space but utilizes motion and energy storage (biasing member) to generate the necessary impact forces. This dynamic approach allows effective seismic wave generation within a compact volume.
4Volume of moving object
If solenoid driven hammers are used to generate impact, then compact arrangement is achieved, but the pulse wave strength becomes relatively weak
Solution Approach 1:
The biasing member (spring) is pre-loaded to store potential energy before the hammer impact. This preliminary energy storage allows the hammer to deliver a stronger impact force than would be possible with solenoid drive alone, while maintaining a compact design.
Solution Approach 2:
The system uses periodic actuation of the hammer mechanism, where the biasing member is repeatedly loaded and released to generate successive impact pulses. This periodic action with energy accumulation allows strong pulse generation in a compact format.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid and accurate seismic testing at greater depths with improved signal strength and reduced resonance noise, facilitating efficient characterization of soil properties through continuous sensing and localized measurements.
Implementation Method 1
a biasing member for biasing the hammer into contact with a surface... the spring stores elastic strain energy when moved by the actuator to the primed position
Implementation Method 2
releasing the hammer, the impact surface may be impacted with a consistent force for generating a repeatable seismic wave signal
Data Source
AI summary
Seismic soil probe (1) comprising a body for insertion into the soil, a seismic sensor (3) located at a first region of the body, and a seismic generator (2) located at a second region of the body for emitting seismic signals. The seismic generator (2) comprises a hammer (6), a biasing member (7) for biasing the hammer (6) into contact with a surface (21), and an actuator (5) operable to move the hammer (6) against the bias away from the surface (21) to a primed position and to release the hammer (6) from the primed position for impacting the surface (21) to generate a seismic wave signal.