【作者】 何夕平；

【导师】 王国体；

【作者基本信息】 合肥工业大学 ， 水利工程， 2005， 硕士

【摘要】 随着国民经济的发展,在不良地质条件下修建结构物的需求越来越迫切,与此同时,上部建筑对地基承载力和沉降的要求也日益提高。矛盾的激化,推动了地基处理技术和方法的不断更新,其中,粉体喷射深层搅拌桩加固软土地基,由于其见效快,经济效益显著,已被广泛应用于国内外工程实践中。 本文详细论述了粉体喷射搅拌桩复合地基的形成条件、加固机理和适用情况,详细介绍了粉喷桩单桩竖向承载力的设计计算,粉喷桩复合地基的设计计算,粉喷桩复合地基下卧层的验算和粉喷桩复合地基几种沉降验算方法,最后对粉喷桩复合地基的设计步骤进行了归纳和总结。 论文结合大兴港石油库地基加固采用粉喷桩复合地基的工程实例,对其设计、施工方案的选择和施工工艺过程以及施工的注意事项做了全面的论述,并在施工现场对地基加固的质量做了全面的检测。包括:低应变反射波法基桩动测、截取桩段无侧限抗压强度试验、单桩竖向静载荷抗压试验、单桩竖向复合地基静载荷抗压试验和沉降观测等,并对粉喷桩质量检测结果从桩身完整性、承载力和沉降等几个方面做了系统的分析。说明该工程的质量满足设计要求,但从承载力方面实际能够承受的承载力远大于设计的承载力,实际沉降量和沉降差远比设计的限值要小,工程设计从检测结果看远没有充分发挥复合地基的性能,造成了不必要的浪费。说明复合地基的设计对不同的地质条件根据经济效益、社会效益、环境效益等综合效益考虑采用长短桩复合地基设计、变参数复合地基设计、低强度桩复合地基设计、复合材料型水泥土搅拌桩的设计等复合地基的优化设计,已成为复合地基的发展趋势,同时不断探索和研究此方面复合地基的施工工艺与质量检测也是我们的努力方向。更多还原

【Abstract】 With the development of national economy, It is so urgent to achieve project on bed foundation. In tbe same time, it is harder to get the foundation suitable to upper building by increasing load-bearing capacity of basement and decreasing settlement of ground. With the criticism sharply, more and more foundation treatment method appears. Among which DJM is widely used in domestic project because of its quick affection and good economical benefits.This paper discusses detail information of forming condition, reinforcing mechanism and applicable condition of DJM (Deep Jet Mixing of Dry Cement-soil Method) composite foundation. It also introduces design and calculation of single pile axial bearing power and composite foundation of dry cement-soil column, as well as check of substratum and several checking methods of sedimentation of composite foundation of dry cement-soil column. This paper gives a summing-up of designing steps of composite foundation of dry cement-soil column.Using an petrol storeroom of Da Xin port engineering project as example, the paper introduces overall designing, choice of construction method, construction technology and construction issues that needs attention. The quality detection of composite foundation was performed on the construction site. Methods being used include: low strain reflectivity dynamic testing of piles, static load test, lab test , Single pile axial bearing power, .... etc. An overall system analysis was given on the dry cement-soil column quality detection result in the aspects of pile body integration, bearing power and sedimentation, and it proves that the construction quality meets the requirements. However, from the actual bearing power point of view, it can bearing much more than the designed bearing power, and the actual quantity of sedimentation and differential settlement are smaller than the designed limitation. Thus, from the quality checking result, we can see that the construction design did not take advantage of the composite foundation, which caused unnecessary waste. In the field of the composite foundation design, it is a trend to use the combination of long and short pile composite foundation design, varied parameter composite foundation design, low load pile composite foundation design, combined material concrete design etc based on the economy efficiency, society efficiency, environmental efficiency and the overall efficiency for different geologycondition. It is our continuous effort to explore and research the construction technology of the composite foundation and quality detection.更多还原