What term describes the dowels or pins driven into the earth around a shaft for support?

The term that describes the dowels or pins driven into the earth around a shaft for support is "spiling." This technique is often employed in engineering and construction to provide lateral support and prevent soil movement when excavating or constructing deep foundations, particularly in areas susceptible to soil instability.

Spiling involves inserting these support elements into the ground to stabilize the surrounding soil and reduce the risk of collapse or shifting during the excavation process. This method is critical in ensuring the safety and integrity of both the excavation site and any structures built above it.

In contrast, soil-structure resonance refers to the phenomenon where the natural frequency of the soil matches the frequency of the structure, potentially leading to amplified vibrations. Site coefficients relate to the amplification of seismic waves as they pass through different geological materials, which is important for earthquake engineering but not directly related to physical support structures. The term "sufficiently active" typically refers to a geologic hazard threshold but does not address the structural support aspect involved with dowels or pins.