【作者】 顾恒星；

【导师】 胡华；

【作者基本信息】 厦门大学 ， 结构工程， 2009， 硕士

【摘要】 软弱岩土在动载作用下的加速流变易于引发岩土滑动失稳、地基沉降倾斜等岩土地质灾害。因此,研究软弱岩土的动态流变特性和突发岩土地质灾害的流变动力学机制具有重要的理论和现实意义。本论文结合国家自然基金“软弱岩土突发重大地质灾害的流变动力学机制研究”研究课题,在广泛查阅国内外相关文献的基础上,重点研究了厦门海相沉积软土在动载作用下的流变特性,并运用突变理论,结合软土动态流变试验结果,研究了软土流变过程中突变破坏形式,主要研究内容如下:1.分析总结了自然界各种常见动态荷载的力学特点及作用模式,为研究软土动态流变特性提供加载依据。2.以厦门海相沉积软土为代表性试样,以常见呈正弦变化的动态荷载为例,进行动三轴流变试验。通过试验结果分析,研究了动载作用下不同频率、幅值对轴向动应变、应变速率、应变加速度以及应力应变关系的影响特性。3.依据已有的流变模型和流变方程,运用拉氏变换解析求解方法,推导计算正弦荷载作用下的软土应变、应变速率和应变加速度的解析表达式,并定性分析了半周期内的软土流变特性。4.基于软土动三轴流变试验结果,依据突变理论建立了相应的尖点突变方程,分别计算分析了试样在正弦荷载不同频率下的突变破坏形式,分析验证了软土在动三轴流变试验中的流变破坏过程。更多还原

【Abstract】 Geotechnical and geological disasters, such as geotechnical slide instability, the settlement inclination of foundation were initiated easily by the accelerating rheology of soft rock-soil under the dynamic loading. Therefore, it is of important theoretical and practical significance to research on the dynamic rheological properties of soft rock-soil and the rheological dynamic mechanism of bursting out geotechnical and geological disasters. Combining with the research subject of research on the rheological dynamic mechanism of bursting out serious geotechnical and geological disasters from national nature fund, based on the widely consulting the home and aboard related literatures, this paper mainly studies on the dynamic rheological properties of the marine sedimentary soft soil in Xiamen under dynamic loading, and studies on the form of catastrophic failure in the rheological process of soft soil by the catastrophe theory, combining with the dynamic rheological test results of soft soil, the main research contents are as follows:1. The analysis and summary on mechanical characters and mode of action of various common dynamic loading in nature supply the loading basis for the study on the dynamic rheological properties of soft soil.2. The dynamic triaxial rheological test is conducted with representative sample of the marine sedimentary soft soil in Xiamen under the common dynamic loading showed sine functions as example. The influencing characteristic of different frequency and amplitude of dynamic loading for the dynamic axial strain, strain rate, strain acceleration, and the stress-strain relationship are studied by analyzing test results.3. According to the existing rheological model and rheological equation, the analytical expressions of soft soil strain, strain rate and strain acceleration under the loading of sine are derived and calculated by the analytic method of Laplace transform, the rheological properties of soft soil are qualitative analyzed in half-period.4. Based on the dynamic triaxial rheological test results, the corresponding cusp catastrophe equation is established by the catastrophe theory, the form of catastrophic failure for sample under the loading of sine with different frequency is calculated and analyzed respectively, which verify the failure process of soft soil in the. dynamic triaxial rheological test.更多还原