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Spectral analysis of surface waves (SASW) and multichannel analysis of surface waves (MASW) are the two main active surface wave methods, and their common inversion schemes are effective mode (EM) inversion and fundamental mode (FM) inversion, respectively. The former has a more rigorous inversion scheme, which considers receiver locations and dynamic response, while the latter has a more convenient dispersion analysis and fast inversion process. This paper introduces an improved dynamic response solution for elastic layered media subjected to vertical load. It is fast, accurate, and unconditionally stable, facilitating the full-wavefield inversion in terms of the frequency–velocity spectrum (FVS). The MASW FVS inversion merges the convenience and robustness of MASW dispersion analysis with the rigorous inversion scheme adopted by SASW. It is based on the actual dynamic response at receiver locations and takes into account possible higher modes and nonRayleigh waves. In this study, various types of synthetic velocity profiles are used to compare the inversion results among three different inverted schemes (SASW EM, MASW FM, and MASW FVS inversion). The results indicate that, when phase-unwrapping in SASW is not problematic, SASW EM inversion and MASW FVS inversion are theoretically sounder and produce better inverted results than the MASW FM inversion, while the process of MASW FVS inversion is more convenient and robust. Finally, a field example is used to further demonstrate the advantages of FVS inversion and its applicability. [ABSTRACT FROM AUTHOR]

Time domain reflectometry (TDR) technology has become a valuable tool for detecting displacements and locating shear planes in rock or soil slopes. It is based on transmitting an electromagnetic pulse into a coaxial cable grouted in rock or soil mass and watching for reflections of this transmission due to cable deformity induced by the ground deformation. Early detection of localized shear deformation in soft soils and quantifying the shear displacement using TDR remains a challenging work. The TDR response due to localized shear deformation is affected by cable resistance, soil-grout-cable interaction, and shear bandwidth. A comprehensive TDR wave propagation model considering cable resistance is introduced to model TDR response to cable deformity. Effects of the influencing factors on the relationship between the reflection spike and the shear displacement are investigated through laboratory tests and numerical simulations. The implications to enhancing TDR response and quantifying shear displacement are stressed. Practical suggestions are made, including procedure for correcting resistance effect, selection of cable and grout, and how to quantify shear displacement using TDR. CE Database subject headings: Deformation; Slope stability; Displacement; Cables; Landslides; Monitoring.

Dispersion analysis in surface wave testing is conventionally associated with a certain method of data acquisition, such as phase angle analysis in the two-station spectral analysis of surface wave (SASW) method and two-dimensional (2D) multistation wavefield transformation in the multistation analysis of surface wave (MASW) method. A new procedure has been developed to reconstruct the SASW data as MASW-imitating data, taking advantage of the 2D multistation wavefield transformation to better analyze the SASW data. Numerical simulations and a real-world example demonstrate the feasibility of this procedure, but also reveal an unwanted side effect associated with aliasing. A common-receiver survey is proposed for future experiments to eliminate this unwanted side effect and at the same time increase the lateral resolution. [ABSTRACT FROM AUTHOR]