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<br />. <br /> <br />. <br /> <br />. <br /> <br />) <br /> <br />EM 1110-2-1913 <br />31 Mar 78 <br /> <br />CHAPTER 3 <br /> <br />LABORATORY TESTING <br /> <br />3-1. General. <br /> <br />a. Reference should be made to EM 1110-2-1906 (ref. A-3a(7)) for <br />current soil testing procedures, and to EM 1110-2-1902 (ref. A-3a(4)) <br />for applicability of the various shear strength tests in stability <br />analyses. <br /> <br />, <br />! <br /> <br />b. Laboratory testing programs for levees ~i11 vary from minimal <br />to extensive, depending on the nature and importance of the project and <br />on the foundation conditions, ho~ ~ell they are kno~, and ~he~her <br />existing experience and correlations are applicable. Since shear and <br />other tests to determine the engineering properties of soils are ex- <br />pensive and time-consuming, testing programs generally consist of ~ater <br />content and identification tests on most samples and shear, consolida- <br />tion, and compaction tests only on representative samples of foundation <br />and borro~ materials. It is imperative to use all available data such <br />as geological and geophysical studies, ~hen selecting representative <br />samples for testing. Soil tests that may be included in laboratory <br />testing programs are listed in table 3-1 for fine-grained cohesive soils <br />and in table 3-2 for pervious soils, together with pertinent remarks on <br />purposes and scope of testing. <br /> <br />.~ . <br /> <br />3-2. Classification and Water Content Determinations. P1ter soil <br />samples have been obtained in subsurface exploration of levee founda- <br />tions and borrow areas, the first and essential step is to make visual <br />classifications and water content determinations on all samples (except <br />that water content determinations should not be made on clean sands ~~d <br />gravels). These samples may be jar or bag samples obtained from test <br />pits, disturbed or undisturbed drive samples, or auger samples. Field <br />descriptions, laboratory classifications, and ~ater content values are <br />used in preparing graphic representations of boring logs. After examin- <br />ing chese data, samples of fine-grained soils are selected for Atterberg <br />liDits tes~s, and samples of coa:se-graine~ soils for gradation tests. <br /> <br />Section I. Fine-Grained Soils <br /> <br />3-3. Use of Correlations. Comparisons of Atterberg limits values with <br />natural water contents of foundation soils and use of the plasticity <br />chart itself (fig. 3-1), together with split-spoon driving resistance, <br />geological studies, and previous experience often will indicate poten- <br />tially ~eak and compressible fine-grained foundation strata and thus the <br /> <br />3-1 <br />