Dynamic-static Characteristics Of Marine Sediments From Zhoushan Seas

Dynamic shear moduli and damping factors are two predominant parameters for the dynamic response analysis of geotechnical engineering. They play important roles in structure design and safety evaluation, too.Dynamic shear moduli and damping factors of undisturbed soil samples determine marine structures’ working performances because they often work under complicated dynamic loads.The marine drilling technique must meet the requirements of undisturbed soil samples. Due to the dangerous oceanic conditions, some advanced apparatuses and techniques such as large drilling barges etc were used to meet the requirements for undisturbed soil samples that would be tested for the reliable data of dynamic shear moduli and damping factors. Therefore, this research needs great fund and the tests data are highly valuable for marine application.Based on these facts, the dissertation’s work will focus mainly on the static-dynamic and physical-mechanical characteristics of marine strata from Zhoushan seas with resonant column apparatus and dynamic tri-axial system tests.The principal results of this study are showed below:The primary physical characteristics system were established for marine strata; the compression coefficients, the coefficients of main consolidation and secondary consolidation were offered based on uni-consolidation tests; the mathematical mapping between main consolidation and sedimentation ratio was deduced with the approach of Terzaghi consolidation theory.Calibration tests were applied for GDS resonant column system and 4 aluminum units were tested as samples to ascertain the systems’ inertia moment which is the crucial and natural parameter for resonant column tests.The dynamic shear moduli and damping factors of marine strata from Zhoushan seas were studied under confining pressure turbulences with low strain development. Themathematical relation between maximal dynamic shear modulus and dynamic shear strain was studied, too.The constitutive models under low strain conditions were established for marine strata of Zhoushan seas. The sensitivity analyses for constitutive models’ parameters were applied. The normalized dynamic constitution under low strain conditions was created for the marine strata by the comparison of these primary parameters’ values from the tests in this dissertation and national standards etc.The dynamic strength of the marine strata was analyzed with GDS tri-axial system and the cyclic loading condition was included in the tests. Meanwhile, the dynamic strain characteristics were also studied based the tests. The key dynamic shear strength indexes were offered from the tests.These results in this paper are helpful for both marine engineering application and academic research.