北部湾吹填场地海积软土动力与强度特性试验研究

发布时间：2018-04-05 03:26

本文选题：海积软土　切入点：动力特性　出处：《广西大学》2017年硕士论文

【摘要】：吹填场地往往下伏着大面积、深厚的沉积相软土,在发生地震时有很大可能会对地震波产生放大作用,继而会加剧吹填场地上部建筑的损害,因此对吹填场地海积软土的动力响应研究极为必要。含水量、固结度及围压作为影响海积软土动力与强度特性的因素,分析以上因素对海积软土动力特性的具体影响是本文主要探讨的问题。本文通过GDS动三轴仪对防城港企沙工业园区吹填场地下伏海积软土进行了大量的动力测试。研究了不同含水量、固结度与围压对海积软土动力与强度特性的影响,试图为吹填场地抗震设计及防震减震提供经验及数据支持。主要的研究内容包括海积软土基本物理力学参数的试验、不同因素作用下海积软土动变形试验、不同因素作用下的动强度试验。本文通过以上的工作内容得出的结论如下。1.不同的动应力幅值下的动应变呈现了不同的规律,随着动应力幅值的增大动应变从平稳状态往扩张状态过渡;围压、含水量、固结度对于海积软土的滞回曲线与骨干曲线的发展、动弹性模量与阻尼比的大小有极大影响。根据现有的试验数据,利用Hardin-Drnevich双曲线模型对各骨干曲线进行了拟合,计算出各试验条件下的最大阻尼比与最大动弹模,并建立了动弹性模量衰减模型。2.确定了以10%的轴向应变作为试样破坏标准。围压与含水量对于海积软土动强度有较大影响,随着围压增大动强度越大,而含水量越大动强度越小。计算出了不同含水量与破坏振次的动强度指标cd、φd,结果表明动强度指标cd、φd会随着含水量与破坏振次的增大而减小。
[Abstract]:Filling sites are often covered with large areas of deep sedimentary soft soil, which is likely to magnify seismic waves in the event of an earthquake, which in turn will aggravate damage to the upper building of the filling site.Therefore, it is necessary to study the dynamic response of marine soft soil on the filling site.Water content, consolidation degree and confining pressure are the factors that affect the dynamic and strength characteristics of marine soft soil, and it is mainly discussed in this paper to analyze the specific influence of the above factors on the dynamic characteristics of marine soft soil.In this paper, a large number of dynamic tests have been carried out on the underground voluminous soft soil of the blowing yard in Jisha Industrial Park of Fangchenggang by using the GDS dynamic triaxial instrument.The effects of different water content, consolidation degree and confining pressure on the dynamic and strength characteristics of marine soft soil are studied in this paper.The main research contents include the test of the basic physical and mechanical parameters of the marine soft soil, the dynamic deformation test of the marine soft soil under different factors, and the dynamic strength test under the different factors.The conclusions of this paper are as follows. 1.With the increase of the amplitude of dynamic stress, the dynamic strain changes from stationary state to expanding state, confining pressure, water content,The degree of consolidation has great influence on the development of hysteretic curve and backbone curve of marine soft soil and the magnitude of dynamic elastic modulus and damping ratio.According to the existing test data, the Hardin-Drnevich hyperbolic model was used to fit the backbone curves, the maximum damping ratio and the maximum dynamic elastic modulus were calculated under each test condition, and the dynamic modulus attenuation model was established.The axial strain of 10% is used as the failure criterion.Confining pressure and water content have great influence on the dynamic strength of marine soft soil. With the increase of confining pressure, the dynamic strength is larger, but the larger the water content is, the smaller the dynamic strength is.The dynamic strength indexes cdand 蠁 d of different water content and failure times are calculated. The results show that the dynamic strength index cdand 蠁 d decrease with the increase of water content and failure times.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U652.2

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