Closure to “Discussion of ‘Measurement of Stiffness Anisotropy in Kaolinite Using Bender Element Tests in a Floating Wall Consolidometer’ by X. Kang, G.-C. Kang, and B. Bate” by Coffman, Salazar and Zhao

Abstract

Abstract The authors appreciate the interest of the discussers in this paper. The main arguments of the discussers were: (1) comparing the back-pressure saturated, constant-rate-of-strain consolidation device that incorporated bender elements (BP-CRS-BE device) developed by the discussers to the floating wall consolidometer based bender element testing system in the original paper (Kang, X., Kang, G.-C., and Bate, B., 2014, “Shear Wave Velocity Anisotropy of Kaolinite Using a Floating Wall Consolidometer-Type Bender Element Testing System,” Geotech. Test. J., Vol. 37, No. 5, pp. 869–883. [DOI: 10.1520/GTJ20120205]); (2) requesting the quantification of both the system lag and the machine deflection; (3) suggesting the authors use cross correlation method to determine the first arrival time because Vs values obtained by time domain method are “only approximate,” while the latter was the only method used by the discussers in their referenced work (Salazar, S. E. and Coffman, R. A., 2014, “Design and Fabrication of End Platens for Acquisition of Small-Strain Piezoelectric Measurements during Large-Strain Triaxial Extension and Triaxial Compression Testing,” Geotech. Test. J., Vol. 43, No. 2. pp. 1–11. [DOI: 10.1520/GTJ20140057]); and (4) making misleading arguments regarding the compression and shear waves measurements. In this closure, the authors first briefly compared the BP-CRS-BE device to the floating wall consolidometer based bender element testing system, and pointed out that (1) the well-documented wavelength ratio (Rd ratio) consideration in designing a bender element device and the seemingly unsatisfaction of such consideration in the BP-CRS-BE device, and that (2) both the lack of details in B-value checking to examine saturation and the lack of shear wave velocity resulted from the BP-CRS-BE device to substantiate the arguments of the discussers. Then the authors provided the requested quantifications of both system lag and machine deflection to address some postulations by the discussers. The authors disagreed with Arguments 3 and 4 made by the discussers, and respond accordingly.