Undisturbed Sampling and Laboratory Shearing Tests on a Sand with Various Fines Contents

Abstract

The eŠects of plastic or non-plasticˆnes on the static and cyclic strength of sand have been a subject of laboratory studies for many decades. These studies have not lead to a concensus as to howˆnes can aŠect the behavior of sand. Earlier studies have mostly been limited to tests on reconstituted specimens. Some of the controversies stem from the concerns that reconstituted specimens may not be able to duplicate the soil fabric in theˆeld. The authors used Laval sampler to retrieve high quality samples with a wide range ofˆnes contents in Central Western Taiwan. A test site was developed in Yuan Lin Township where standard penetration test (SPT), seismic piezocone (SCPTU) andˆeld shear wave velocity (Vs) measurements were performed in addition to Laval sampling. A series of monotonic and cyclic triaxial tests with Vs measurements were conducted on natural and reconstituted Yuan Lin Soil (YLS) specimens withˆnes contents ranging from 18 to 89z. While the study conˆrmed some of the earlierˆndings which indicated thatˆnes tend to weaken the soil specimens, the results also showed that the eŠects ofˆnes may be exaggerated according to tests on reconstituted specimens.

Field Evaluation of the Cyclic Strength versus Cone Tip Resistance Correlation in Silty Sands

“…A term``silt/sand'' is used as an abbreviated method to describe soils that may be classiˆed as silty sand or sandy silt. Parts of the laboratory test results on undisturbed soil samples have been reported earlier (Huang and Huang, 2007;Huang et al, 2008). This paper places its emphasis onˆeld tests and their interpretations.…”

“…The other Laval samples were extruded from the sampling tube in theˆeld and sealed in wax before transportation. Details of the sampling technique are referred to in Huang and Huang (2007).…”

“…Theˆeld CRR values under the assumed K value were inferred from CRRCTX obtained from isotropically consolidated cyclic triaxial tests, using Eq. (8). For YLS, the CRRCTX conducted under sc ?…”

“…All specimens (70 mm diameter and 150 mm high) involved in a set of cyclic triaxial tests were trimmed from the same Laval sample and at exactly the same depth. The details of trimming and thawing LS specimens are described in Huang and Huang (2007). Because of the high compressibility, the void ratio, e after specimen consolidation in the triaxial cell was used in analyzing the test data.…”

“…7 were used to infer CRR using Eq. (8). The average value of qt from comparable depths where the undisturbed samples were taken was normalized using Eq.…”