Angled Subsurface Seismic Barriers for Wave Attenuation
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Solution Overview
Problem
Existing earthquake engineering practices are inadequate for protecting high-value structures from seismic damage, as retrofitting existing structures is cost-prohibitive and challenging, and current subsurface seismic barrier technologies are limited in effectiveness and representativeness.
Innovation Solution
The implementation of engineered subsurface seismic barriers, including angled borehole or trench arrays that form metamaterials, designed to reflect, refract, absorb, or divert destructive seismic waves, providing broadband redirection and attenuation of ground motion amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retrofitting existing structures with earthquake engineering practices is implemented, then seismic protection is improved, but cost and implementation difficulty increase significantly
Solution Approach 1:
The patent introduces subsurface seismic barriers as an intermediary structure between the earthquake source and the protected building. These barriers (boreholes or trenches) are placed in the ground to intercept and attenuate seismic waves before they reach the foundation, thereby protecting the structure without requiring modification of the building itself. This resolves the contradiction by providing seismic protection through a separate intermediary system rather than direct retrofitting of the structure.
Solution Approach 2:
The seismic barrier is segmented into multiple discrete elements (individual boreholes or trench segments) arranged in specific patterns. This segmentation allows the protection system to be implemented in a modular fashion, reducing implementation difficulty while maintaining overall effectiveness. The segmented approach also allows for easier installation and adaptation to existing structures compared to monolithic retrofitting solutions.
2Reliability
If vertical borehole structures are used to block seismic waves, then some wave attenuation is achieved, but most waves diffract around the structure and strike the protection area with considerable force
Solution Approach 1:
The patent transitions from two-dimensional vertical borehole walls to three-dimensional configurations by adding angular orientation and lateral extent. The boreholes are inclined at angles rather than purely vertical, and arranged in patterns that create overlapping attenuation zones. This dimensional enhancement blocks diffracted waves that would otherwise pass around vertical structures, significantly improving wave attenuation effectiveness.
Solution Approach 2:
The seismic barrier employs asymmetric configurations where boreholes are inclined at specific angles rather than uniformly vertical. The angular orientation is optimized to intercept waves coming from specific directions, creating asymmetric attenuation patterns that better match the directional nature of seismic wave propagation. This asymmetric design prevents waves from diffracting around the barrier as they would with symmetric vertical structures.
3Reliability
If deep boreholes are drilled to protect against seismic waves, then wave attenuation improves, but cost and complexity increase
Solution Approach 1:
The patent optimizes borehole parameters (depth, angle, spacing, diameter) to achieve effective seismic wave attenuation without requiring excessive depth. By carefully selecting and adjusting these parameters, the system achieves protection against a broad range of seismic wavelengths using moderate-depth boreholes arranged in specific angular patterns, rather than requiring very deep vertical holes. This parameter optimization reduces both cost and implementation complexity while maintaining reliability.
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
These subsurface seismic barriers effectively reduce seismic wave amplitudes within protected zones by up to 40 dB, offering flexible retrofitting options and broader wavelength protection, while minimizing the need for deep boring, thus addressing the limitations of existing technologies.
Implementation Method 1
seismic barrier (or metamaterial) can include borehole array complexes or trench complexes that reflect, refract, absorb, divert, or otherwise impede destructive seismic surface waves
Implementation Method 2
seismic barrier (or metamaterial) can include borehole array complexes or trench complexes that reflect, refract, absorb, divert, or otherwise impede destructive seismic surface waves
Implementation Method 3
seismic barrier (or metamaterial) can include borehole array complexes or trench complexes that reflect, refract, absorb, divert, or otherwise impede destructive seismic surface waves
Implementation Method 4
The structural arrangement can be configured to attenuate power from the anticipated elastic (e.g., seismic) wave within the protection zone relative to power from the anticipated elastic wave external to the protection zone
Data Source
AI summary
A seismic wave damping structure can include a structural arrangement including at least one pair of elements, each angled with respect to a vertical and extending into the earth and toward a protection zone. The elements thus form a tapered aperture, the structural arrangement defining the protection zone at an upper portion of the aperture. Each element defines an inner volume and contains a medium resistant to passage of an anticipated seismic wave in earth having a wavelength at least one order of magnitude greater than a cross-sectional dimension of the inner volume of each of the elements. The medium is at least one of air, gas, water, and viscous fluid. The structural arrangement is configured to attenuate power from the anticipated seismic wave within the protection zone relative to power from the anticipated seismic wave external to the protection zone.