塑料排水板处理超软土地基加固效果研究

发布时间：2018-06-13 17:23

本文选题：排水板滤膜 + 真空预压　；参考：《天津大学》2014年硕士论文

【摘要】：随着经济的快速发展,围海吹填造陆地区越来越多,吹填土面积越来越大。而滨海吹填土地基具有含水率高、渗透系数小、欠固结程度高、力学强度低等性质,为满足工程需要,必须对吹填到岸的超软土进行加固处理,在实际工程中真空预压技术作为排水固结法的一种被广泛采用,并且取得了一定成绩。在真空预压法中塑料排水板以其便于施工、质量稳定、可批量生产等优点被广泛的用作竖向排水通道,然而塑料排水板种类繁多,仅其外包裹的起过滤作用的滤膜就有多种类型,性能差别也较大,应用及科研中发现,排水板滤膜对真空预压效果会产生一定影响。为探究不同类型排水板滤膜对真空预压效果的影响,本文自行设计室内模型试验,对三种等效孔径具有明显差别的排水板滤膜进行研究。试验中,将三种滤膜做成竖向排水体,分别对含水率较高的滨海吹填土进行真空加固。试验过程中,监测膜下真空度、泥面沉降、出水量、孔隙水压力的变化,对比分析同种滤膜外不同区域及不同滤膜外相同区域土体的排水固结情况;试验前后,对土体的含水率及十字板剪切强度进行测试,评价各滤膜对土体的真空加固效果;通过对比分析,试验后滤膜附近区域土体的颗分曲线,评价不同类型排水板滤膜在真空加固过程中的土颗粒流失情况,及同种滤膜外不同区域土粒流失量差异。研究发现:在真空作用下,土体排水固结速度受排水板滤膜渗透性及土颗粒孔隙通道畅通程度影响,滤膜渗透性好、土体孔隙通道畅通、渗径短时土体排水固结效果好;等效孔径较大的排水板滤膜,抗淤堵能力强,加固效果较好;滤膜纤维力学强度高时,抵抗变形能力强,抗淤堵效果好;加固过程中,滤膜附近区域土颗粒发生流失,且距离竖向排水体越近土粒流失越多;等效孔径越大,土粒流失量越多。
[Abstract]:With the rapid development of economy, there are more and more reclamation areas. In order to meet the need of engineering, it is necessary to reinforce the super-soft soil which is filled to the shore, which has the properties of high moisture content, low permeability coefficient, high underconsolidation degree and low mechanical strength. As a kind of drainage consolidation method, vacuum preloading technology has been widely used in practical engineering, and some achievements have been made. In vacuum preloading, plastic drainage board is widely used as vertical drainage channel because of its advantages of easy construction, stable quality and batch production. However, there are many kinds of plastic drainage boards. There are many kinds of filter membrane which is wrapped outside and the performance is different. It is found in the application and scientific research that the drainage plate filter membrane will have certain influence on the vacuum preloading effect. In order to investigate the effect of different kinds of drainage plate filter membrane on vacuum preloading, this paper designed the model test in the room, and studied three kinds of drainage plate filter membrane with obvious difference in equivalent aperture. In the experiment, three kinds of filter membrane were made into vertical drainage body, and vacuum reinforcement was carried out on coastal fill with high moisture content. During the test process, the changes of vacuum degree, mud surface settlement, water output and pore water pressure under the same membrane were monitored, and the drainage consolidation of different areas outside the same filter membrane and the same area outside the same filter membrane was compared and analyzed before and after the test. The moisture content of soil and shear strength of cross plate were tested to evaluate the vacuum reinforcement effect of each filter membrane. The soil particle loss of different types of filter membrane in vacuum reinforcement and the difference of soil particle loss in different regions outside the same filter membrane were evaluated. The results show that the consolidation speed of soil is influenced by the permeability of filter membrane and the unblocked degree of pore passage of soil particle under vacuum. The permeability of filter membrane is good, the pore channel of soil is unblocked and the consolidation effect of soil is good when the seepage diameter is short. The filter membrane with large equivalent pore diameter has strong anti-silting ability and good reinforcement effect; when the mechanical strength of filter membrane is high, it has strong resistance to deformation and good anti-silting effect; in the process of reinforcement, soil particles in the area near the filter membrane are lost. The larger the equivalent pore diameter is, the more the loss of soil particles is, the closer it is to the vertical drainage body, the more soil particles are lost.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU447;TU472

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