Influence of Contents of Fine Particles in Marine Soil on Dynamic Stability of Wharfs
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摘要: 为探究海洋土细颗粒含量对非线性变形性状的影响,对不同细颗粒含量的土体展开三轴固结不排水剪试验,得出了细颗粒含量对海洋土非线性变形性状的影响规律,结果显示:伊利土含量在0%~18%时,存在一个强度最大值,其所对应的伊利土含量为12%;当其小于12%时,土样性质主要由砂土决定,呈现应变软化特性;当伊利土含量大于临界值时,土样性质由伊利土含量主导,呈现应变硬化特性。耦合不同海洋土细颗粒含量的非线性变形特性,建立了在波浪动荷载作用下的地基-桩-上部结构三维动力响应数值模型,结果显示:当土的峰值强度较大时,软化型变形特性让码头损伤程度更严重。当峰值强度较低时,硬化型变形特性让码头损伤程度更严重;相同峰值强度下硬化型地基上码头面板最大等效应力和最大剪应力的峰值比软化型地基上的大,地基土峰值强度小的地基上码头面板应力比峰值强度大的要大;而相同峰值强度地基中,软化型地基的土层最大应力比硬化型地基的大,峰值强度小的地基土最大应力更大。这表明海洋土细颗粒含量对码头动力稳定性有着显著影响,在设计时应该考虑不同力学性质的地基土所产生的非线性响应。Abstract: A series of triaxial consolidated undrained shear tests were conducted on marine soil with different contents of fine particles, and the influence of contents of fine particles on nonlinear deformation properties of marine soil was obtained. The results indicated that when the content of illite was between 0% to 18%, the maximum strength of soil was in the illite content of 12%. When it was less than 12%, the properties of soil were mainly determined by sandy soil, and the deformation of the soil exhibited strain-softening properties. When the illite content was more than 12%, the properties of soil were dominated by the illite content, which exhibited strain-hardening properties. Coupled with the nonlinear deformation characteristics of different contents of fine particles in marine soil, a three-dimensionally numerically dynamic response model for a foundation-pile-superstructure under wave dynamic loads was constructed. The analysis results indicated that when the peak strength of soil was larger, the deformation of strain-softening characteristics would cause more serious damage to wharfs. When the peak strength was lower, the deformation of strain-hardening characteristics would cause more serious damage to wharfs. At the same peak strength, the peak values of the maximum equivalent stress and the maximum shear stress in the dock panels on the hardened foundation were larger than that on the softened foundation, and the stress of the dock panel on the foundation with low peak strength of the foundation soil was larget than that on the foundation with high peak strength. In the foundation with the same peak strength, the maximum stress of strain-softening soil foundation was larger than that of strain-hardening soil foundation, the larger the stress in foundation soil, the smaller the peak strength was. It indicated that the fine particle content of marine soil had a significant impact on the dynamic stability of wharfs, and the nonlinear responses of foundation soil with different mechanical properties should be considered in design.
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Key words:
- sandy soil /
- illite /
- nonlinear deformation /
- numerical simulation
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[1] STICKLE M M, FUENTE P D L, OTEO C, et al. A modelling framework for marine structure foundations with example application to vertical breakwater seaward tilt mechanism under breaking wave loads[J]. Ocean Engineering, 2013, 74(4): 155-167. [2] HÜBLER C, HÄFELE J, GEBHARDT C G, et al. Experimentally supported consideration of operating point dependent soil properties in coupled dynamics of offshore wind turbines[J]. Marine Structures, 2018(57): 18-37. [3] YANG S Y, LIM D I, JUNG H S, et al. Geochemical composition and provenance discrimination of coastal sediments around Cheju Island in the southeastern Yellow Sea[J]. Marine Geology, 2004, 206(1): 41-53. [4] LIU S, SHI X, FANG X, et al. Spatial and temporal distributions of clay minerals in mud deposits on the inner shelf of the East China Sea: Implications for paleoenvironmental changes in the Holocene[J]. Quaternary International, 2014, 349(10): 270-279. [5] TANG Z, WANG Y. The distribution characteristics of clay minerals in the northern South China Sea[J]. Acta Oceanologica Sinica, 1993, 12(1): 145-157. [6] WANG Z, CHEN Z, LI M, et al. Variations in downstream grain-sizes to interpret sediment transport in the middle-lower Yangtze River, China: a pre-study of Three-Gorges Dam[J]. Geomorphology, 2009, 113(3): 217-229. [7] THEVANAYAGAM S, MOHAN S. Intergranular state variables and stress-strain behaviour of silty sands[J]. Geotechnique, 2000, 50(1): 1-23. [8] CHANG C S, MEIDANI M. Dominant grains network and behavior of sand-silt mixtures: stress-strain modeling[J]. International Journal for Numerical & Analytical Methods in Geomechanics, 2014, 37(15): 2563-2589. [9] CHANG C S, YIN Z Y. Micromechanical modeling for behavior of silty sand with influence of fine content[J]. International Journal of Solids and Structures, 2011, 48(19): 2655-2667. [10] LING H, HUA F U, HAN H Q. Experimental study on effects of gradation on strength and deformation of coarse-grained soil[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(S1): 12-16. [11] ZHANG Y N, CHEN Y. A Constitutive Relationship for Gravelly Soil Considering Fine Particle Suffusion[J/OL]. Materials, 2017, 10(10)[2022-05-30]. https://doi.org/10.3390/ma10101217. [12] HARPER R J, GILKES R J. The effects of clay and sand additions on the strength of sandy topsoils[J]. Soil Research, 2004, 42(1): 39-44. [13] BANUPRIYA S, SOUNDARYA M K, CHAKRAVARTHY K. Stress-strain and strength characteristics of sand-silt mixtures[J]. International Journal of Latest Trends in Engineering and Technology, 2015, 6(1): 1-8. [14] TIWARI B, AJMERA B. A new correlation relating the shear strength of reconstituted soil to the proportions of clay minerals and plasticity characteristics[J]. Applied Clay Science, 2011, 53(1): 48-57.
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