水下真空预压技术的应用与研究

发布时间：2018-05-15 17:36

本文选题：水下真空预压 + 岸坡加固　；参考：《天津大学》2015年硕士论文

【摘要】：天津地区由于地质条件较差,故码头结构型式多为高桩码头,而高桩码头的岸坡稳定问题至关重要,尤其是在承台宽度受限条件下的岸坡稳定成为最大难点,因此进行地基加固处理是必要的。陆上真空预压法加固软土地基技术已广泛应用于港口、公路、水利工程等领域,但水下真空预压技术却无大规模应用于工程实践,其原因在于目前水下真空预压的加固机理尚不清楚,水下施工工艺也存在亟待解决的诸多难题。本文结合工程实践,利用理论分析和有限元数值模拟的方法针对水下真空预压技术开展了一系列研究工作,主要研究内容和结论如下:首先,分析了高桩码头及其接岸结构型式特点,并对岸坡稳定性计算方法和岸坡加固方法进行了论述,阐述了窄承台条件下岸坡加固的关键问题。其次,针对天津港中化石化码头具体工程项目,在承台宽度50m的限制条件下对岸坡加固进行了方案比选,论述了水下真空预压的关键技术,对水下真空预压加固方案进行了设计。然后,对水下真空预压现场实测数据进行整理分析,检测结果显示土体最终固结度均在90%以上,水下真空预压达到了预期目的,工艺上得到了进一步检验和完善。在码头挖泥和打桩及上部结构施工过程中,实测原围堤的最大沉降为17mm,土体深层侧向位移最大值为10.4mm,远小于天津港其他高桩码头施工中的变形,进一步验证了设计方案的合理性和水下真空预压的加固效果。最后,本文考虑潮间带膜上附加水压力的作用,通过有限元软件ABAQUS对土体加固过程进行了数值模拟,并将模拟结果和实测数据进行对比,结果显示沉降曲线和孔压消散曲线均拟合良好,验证了有限元数值模拟的可靠性。综上所述,本文结合窄承台条件下岸坡加固的具体工程实践,对水下真空预压技术进行了方案设计和理论分析,并提出了可行的有限元模拟方法,对该技术的推广应用具有一定意义。
[Abstract]:Because of the poor geological conditions in Tianjin, the structure of wharf is mostly high pile wharf, and the slope stability of high pile wharf is very important, especially under the condition of limited width of pile cap, the stability of bank slope becomes the biggest difficulty. Therefore, it is necessary to strengthen the foundation. The technology of strengthening soft soil foundation by land vacuum preloading method has been widely used in port, highway, water conservancy engineering and other fields, but the underwater vacuum preloading technology has not been applied in engineering practice on a large scale. The reason is that the reinforcement mechanism of underwater vacuum preloading is not clear, and there are many problems to be solved in underwater construction technology. Combined with engineering practice, a series of research work on underwater vacuum preloading technology is carried out by theoretical analysis and finite element numerical simulation. The main research contents and conclusions are as follows: first of all, This paper analyzes on the characteristics of high pile wharf and its bank connection structure, discusses the calculation method of slope stability and the method of bank slope reinforcement, and expounds the key problems of bank slope reinforcement under the condition of narrow cap. Secondly, aiming at the concrete project of Sinochem Petrochemical Wharf of Tianjin Port, the scheme of bank slope reinforcement is compared under the limit of 50m width of bearing cap, and the key technology of underwater vacuum preloading is discussed. The reinforcement scheme of underwater vacuum preloading is designed. Then, the field measured data of underwater vacuum preloading are analyzed, the results show that the final consolidation degree of soil is above 90%, the underwater vacuum preloading has achieved the expected purpose, and the technology has been further examined and improved. In the course of dredging, piling and superstructure construction, the maximum settlement of the original embankment is 17mm, and the maximum lateral displacement of the deep soil is 10.4mm, which is much smaller than the deformation of other high-pile wharves in Tianjin Port. The rationality of the design scheme and the reinforcement effect of underwater vacuum preloading are further verified. Finally, considering the effect of additional water pressure on the intertidal zone film, the soil reinforcement process is simulated by finite element software ABAQUS, and the simulation results are compared with the measured data. The results show that both the settlement curve and the pore pressure dissipation curve are fitted well, which verifies the reliability of the finite element numerical simulation. To sum up, combined with the concrete engineering practice of bank slope reinforcement under narrow cap condition, the project design and theoretical analysis of underwater vacuum preloading technology are carried out in this paper, and a feasible finite element simulation method is put forward. It has certain significance for the popularization and application of this technology.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU472.33

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