海相和漫滩相软土振动排水固结特性试验研究

发布时间：2018-06-18 16:16

本文选题：振动排水 + 固结　；参考：《江苏大学》2017年硕士论文

【摘要】：软土在世界各地分布广泛。因其成因不同,不同沉积相的软土具有不同的物理力学性质。另外,不同地区的软土其结构性亦有差别。本文在动力排水固结技术的基础上,采用周期性振动荷载代替冲击荷载,提出振动排水固结法加固海相和漫滩相软土,并同静荷载下的排水效应对比。通过江苏连云港海相和镇江漫滩相软土的室内振动排水固结试验,分析不同沉积相软土的排水固结特性;设计漫滩相软土振动排水固结优化试验方案,探讨其在低频振动作用下提高固结效果的合适参数组合。通过对不同围压的漫滩相软土进行振动排水固结试验,分析该沉积相软土的动力响应。研究的主要内容包括:(1)海相和漫滩相软土的固结特性分析。在海相和漫滩相软土基本物理力学指标分析的基础上,为探究振动荷载作用下两相软土的固结特性,利用自主设计的动态固结渗透仪对海相和漫滩相软土进行振动排水固结试验。在固结初期,对海相和漫滩相软土先施加静载后施加动载与同步施加静动荷载来探究不同加载方式下排水响应。分析了扰动程度对两相软土和含水率对漫滩相重塑土的振动排水固结效应的影响;对两相软土分别施加矩形波、三角波和正弦波来分析波形对其固结效率的影响;探究海相和漫滩相软土轴向累积应变和排水体积应变随时间的变化规律。结果表明:初期先施加静载后施加动载的加载方式的排水固结效果良好;扰动程度越小的软土的固结效率越高;随着含水量增大,振动排水固结效率显著提高;矩形波较其他波形振动荷载能够产生更大的排水体积应变和轴向累积应变;在围压、频率和荷载相同的条件下,当排水体积应变稳定时,漫滩相软土较海相软土固结时间短。(2)漫滩相软土振动排水固结效果分析。对漫滩相软土进行振动排水固结试验,通过调整静载初始值、分级静荷载持续时间以及振动荷载起始时间来探究排水固结效果的影响,根据固结过程中轴向累积应变和排水体积应变,确定振动排水固结法合理参数组合。结果表明:静载初始值、分级加载持续时间、振动荷载起始时间对其轴向累积应变和排水体积应变产生显著影响;在软土固结过程中,频率的变化对软土固结效果影响程度不同。(3)不同围压下漫滩相软土的动力响应分析。在不同围压下,使其排水固结24小时,然后对其先施加静载,后施加不同频率的振动荷载,分析其固结产生的排水体积应变、轴向累积应变和排水体积应变速率,探究其动力响应。结果表明:围压和频率对软土固结具有重要的影响。
[Abstract]:Soft soil is widely distributed all over the world. Because of its different origin, the soft soil of different sedimentary facies has different physical and mechanical properties. In addition, there are differences in the structure of soft soil in different regions. On the basis of dynamic drainage consolidation technique, the cyclic vibration load is used to replace the impact load, and the vibration drainage consolidation method is proposed to strengthen the marine and floodplain soft soil, which is compared with the drainage effect under static load. Through indoor vibration drainage consolidation test of marine and Zhenjiang floodplain soft soil in Lianyungang, Jiangsu Province, the characteristics of drainage consolidation of soft soil with different sedimentary facies are analyzed, and the optimum test scheme of vibration drainage consolidation of soft soil in floodplain is designed. The suitable combination of parameters to improve the consolidation effect under low frequency vibration is discussed. The dynamic response of the sedimentary soft soil was analyzed by vibration drainage consolidation test on the soft soil with different confining pressures. The main contents of the study include the analysis of the consolidation characteristics of marine and floodplain soft soil. Based on the analysis of basic physical and mechanical indexes of marine and floodplain soft soil, the consolidation characteristics of two-phase soft soil under vibration load are investigated. The vibration drainage consolidation test of marine and floodplain soft soil was carried out by using the self-designed dynamic consolidation osmometer. In the early stage of consolidation, the response of draining under different loading modes was investigated by applying static load first and then dynamic load and synchronously applying static load on the marine and floodplain soft soil. The influence of disturbance degree on the vibration drainage consolidation effect of two-phase soft soil and water content is analyzed, the rectangular wave, triangle wave and sine wave are applied to the two-phase soft soil to analyze the effect of waveform on the consolidation efficiency. The variation law of axial cumulative strain and drainage volume strain of marine and floodplain soft soil with time are investigated. The results show that the consolidation efficiency of the soft soil with less disturbance is higher, and the consolidation efficiency of vibration drainage increases with the increase of water content, and the consolidation effect of the loading method with static load first and then dynamic load is good, and the consolidation efficiency of soft soil is higher with the increase of water content. The rectangular wave can produce larger drainage volume strain and axial cumulative strain than other wave vibration load. Under the condition of the same confining pressure, frequency and load, the drainage volume strain is stable when the drainage volume strain is stable. The consolidation time of soft soil in floodplain is shorter than that in marine soft soil. Vibration drainage consolidation test was carried out on the soft soil of floodplain. By adjusting the initial value of static load, the duration of graded static load and the initial time of vibration load, the effect of drainage consolidation effect was investigated. According to the axial cumulative strain and the drainage volume strain during the consolidation process, the reasonable parameter combination of the vibration drainage consolidation method is determined. The results show that the initial value of static load, the duration of step loading and the onset time of vibration load have significant effects on the axial cumulative strain and drainage volume strain, and during the consolidation of soft soil, The dynamic response of the soft soil under different confining pressures is analyzed by the influence of frequency change on the consolidation effect of soft soil. Under different confining pressures, the drainage is consolidated for 24 hours, then static load is applied to it, and then vibration load is applied at different frequencies. The volume strain of drainage, axial cumulative strain and strain rate of drainage volume produced by consolidation are analyzed. Explore its dynamic response. The results show that the confining pressure and frequency have an important effect on the consolidation of soft soil.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU472

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