<p><p><strong>References:<br></strong><em> Schaefer et al. (2016)<br>Massarsch and Heppel (1991)<br>Mitchell (1981)</em></p><p><strong>Method Summary</strong></p><p>The cross-hole test is an in-situ measurement of the wave propagation velocity at small strains between bore holes. Typically, two holes are drilled, cased, and a source is placed in one hole and a receiver in the other hole. The wave is generated from the source and the time for the wave to reach the receivers is evaluated. The source and the receivers are then raised to another elevation and the test is run again. A profile of seismic shear wave velocity with depth can be generated from this information. The wave velocity can then be used to determine the Cyclic Stress Ratio (CSR) which evaluates liquefaction resistance.</p><p><strong>Accuracy and Precision</strong></p><p>This method is generally regarded as an accurate and precise test.</p><p><strong>Adequacy of Coverage</strong></p><p>One cross-hole test is able to cover a large lateral area. The boreholes are typically spaced 10 to 15 feet apart depending on the anticipated shear wave velocity. The number of elevation points per hole, and hence the refinement of the shear wave velocity profile, depends on the importance of the structure being built and the complexity of the ground.</p><p><strong>Implementation Requirements </strong></p><p>Cross-hole testing requires experience-based judgment to determine if obtaining reasonable results.</p><p><strong>General Comments</strong></p><p>The shear wave velocity of the soil is an important parameter for assessing a site’s resistance to liquefaction and lateral spreading resulting from a seismic event. This will have an impact on the site’s ability to support its service load.</p></p>