Elimination of membrane compliance in undrained triaxial testing. I. Measurement and evaluation

Abstract

Several alternative approaches have been suggested for evaluation and correction of the testing errors caused by membrane compliance. The degree to which membrane compliance may affect the results of an undrained test is a function of the soil grain size and overall geometry of the test specimen, as well as specimen density and range of effective confining stresses during a given test. Membrane-compliance effects may be negligible for fine sands and silts tested in conventional 71 mm diameter samples, since even very thin membranes cannot penetrate significantly into the small surficial voids. For medium to coarse sands and gravels, however, membrane-compliance effects may have a significant influence on test results. The scope of this paper is threefold: firstly, to review, examine, and evaluate the variety of methods to measure and characterize membrane compliance; secondly, to develop an improved understanding of the factors affecting membrane compliance; and thirdly, to provide an enhanced, updated, and expanded correlation for estimating membrane compliance characteristics as a function of material grain size for a range of soil types, including a wide range of gradation types and representative grain sizes from silts through gravels.

Damage investigation and liquefaction potential analysis of gravelly soil

“…It then affects the accuracy of the measurement of the pore water pressure and also the magnitude of the effective confining pressure. This effect is decreased with the increase of effective confining pressure (Nicholson et al, 1993). When the confining pressure is 1 kgf/cm 2 , the volumetric strain due to membrane penetration becomes small.…”

A high-cycle accumulation model for sand

“…The isomorphic strain components ampl P and ampl Q are defined in Appendix A. However, careful reinterpretation of our tests considering the membrane penetration effect [37] has revealed that ampl P and ampl Q contribute equally(!) to the accumulation and need not be treated separately.…”

Pseudo Anisotropy Induced by Membrane Compliance in Cemented Granular Soils

“…The gradation curves of Si and RT sands before cementation (Fig. 6) indicates their potential to experience membrane-induced volume change as may be inferred from D50 or D20 (Nicholson et al, 1993). In fact, although 10 and 5 flushes were applied to the silica and RT sands respectively, the micrographs shown in Figs.…”

“…Experience with granular uncemented materials has shown that the volume change due to membrane compliance is a repeatable function of al for particular sample and membrane conditions (Nicholson et al ., 1993). A typical relationship between the unit membrane compliance (Ovn) and a is shown in Fig .…”