波浪荷载作用下砂土变形特性的模拟试验研究

Experimental study on dynamic deformation behavior of sand under wave-induced loading

利用新研制的“土工静力-动力液压三轴-扭转多功能剪切仪”模拟波浪荷载作用,对福建标准砂进行了4组三轴-扭转耦合振动剪切试验,以研究海床砂土在波浪荷载作用下的变形特性及其对砂土初始密度和固结压力的依赖性。试验结果表明,应力-应变呈现出良好的双曲线关系,与等效线性模型理论相吻合;阻尼比和模量随应变幅值的变化规律均依赖于土体的初始密度和固结压力;归一化后的E/Emax-ε及G/Gmax-γ曲线对相对密度和固结压力仍具有明显的依赖性;但完全归一化后的E/Emax-ε/εr及G/Gmax-γ/γr的关系曲线则与固结压力无关。

The wave loading is simulated by a new developed apparatus-“Soil static and dynamic hydraulic triaxial and torsional shear apparatus'. Four groups of triaxial and torsional shear tests have been conducted for Fujian Chinesestandard sand with variation in consolidation pressure and initial relative density by the apparatus to study the dynamicdeformation behavior of the sand under wave-induced loading. It is found that stress and strain curves of sand are similar to hyperbola, which coincide with equivalentlinear theory. It is also shown that the variation of the damping ratio and modulus with the strain amplitude is dependent on the initial relative density and consolidation pressure of sand. Furthermore, the curves of E/E_(max)-εandG/G_(max)-γ still rely on the initial relative density and consolidation pressure. However, results show that the relationship between the modulus normalized by the maximum modulus and the strain normalized by the reference strain is irrelative to the consolidation pressure.