Abstract

The multi-channel analysis of surface waves (MASW) is a widely employed surface wave method. The fundamental mode inversion is the usual scheme in MASW, because separating the fundamental mode from other high modes is feasible with an adequately long array. However, the extracted fundamental mode represents only part of the dynamic characteristics, it may deviate from the theoretical fundamental mode due to truncation effect, and part of it may correspond to another higher mode or leaky mode, resulting in mode misidentification. Conversely, the spectral analysis of surface waves (SASW) method features a more rigorous inversion scheme by matching the effective mode, but it may suffer from the tricky phase-unwrapping in the dispersion data reduction. This study introduces an improved dynamic response solution for elastic-layered media subjected to vertical loads. The proposed dynamic response solution is fast and accurate, facilitating the full wavefield inversion in terms of the frequency-velocity spectrum. The MASW frequencyvelocity spectrum inversion considers testing configuration and comprehensively models all wave phenomena, including near-field effect, truncation effect, and leaky waves. The MASW frequency-velocity spectrum inversion merges the convenience of MASW dispersion analysis with the rigorous inversion scheme adopted by SASW. The new MASW frequency-velocity spectrum inversion is compared with the SASW effective mode inversion and MASW fundamental mode inversion. The results show that both SASW effective mode inversion and MASW frequency-velocity spectrum inversion produce better inverted results than the MASW fundamental mode inversion, while the process of MASW frequency-velocity spectrum inversion is more convenient and robust. Finally, a field example is used to demonstrate the applicability of frequency-velocity spectrum inversion.

Abstract

The resource of resistance to external influences (or sustainability resources) is understood as the ability of natural or natural-technogenic objects and systems to withstand negative impacts and at the same time preserve and maintain their basic functional properties within acceptable or specified limits. The use of the concept of sustainability resources (SR) to assess the risk of a system leaving an acceptable state necessitates a revision of some methodological issues in surveys for construction. Traditionally, the purpose of research is to obtain initial data for design decisions and calculations for various purposes. We emphasize that the existing approach corresponds to the strategy of protection from hazardous processes, and the use of the SR concept to external influences is more consistent with the strategy to prevent negative consequences. In addition, social and environmental factors, combined with global climate change, also increase the risks of hydrometeorological hazards and associated floods, activation of landslides, erosion, and karst-suffusion processes. Reducing these risks has traditionally been achieved by implementing protective engineering controls (or gray infrastructure), but nature-based solutions (green and blue infrastructure) are increasingly being explored. This approach, in our opinion, corresponds to the goals of ensuring rational and sustainable interaction with the geological environment during construction. The methodology is discussed and examples of the use of nature-based solutions are given.