【作者】 贾苍琴；

【导师】 姚环；

【作者基本信息】 福州大学 ， 环境工程， 2003， 硕士

【摘要】 我国地域辽阔，地质环境复杂，工程地质条件因地区不同致使差异很大。各类软弱地基分布面广，区域性很强。因此，在地基加固处理时必须针对当地的实际情况进行。 本文通过室内常规试验对福州地区淤泥及淤泥质粘土的原状土样和扰动土样的物理力学性质进行了分析，观察土样受扰动后一些物理力学指标的变化情况，发现扰动软粘土样的含水量、孔隙比、抗剪强度指标均比原状土样低；并从软粘土的矿物成份、化学成份以及微观结构特征和类型上定性地分析。 采用水泥和粉煤灰为固化剂在室内进行其配合比试验，对含水量不同的软粘土制成不同掺入比的水泥土以及对含水量值固定的软粘土制成水泥、粉煤灰掺入量分别不同的水泥-粉煤灰加固土，并在不同龄期时进行无侧限抗压强度试验；运用X射线衍射和扫描电子显微镜技术，对水泥土及水泥-粉煤灰加固软土的微观结构和机理进行分析。通过测定水泥土及水泥-粉煤灰加固土的无侧限抗压强度，探讨固化剂掺量、龄期对抗压强度的影响；通过对比研究发现，当水泥掺入比为16％，粉煤灰掺入量为水泥重的40％时，加固土的强度最大，并且强度随着软土含水量的增加而降低，随着水泥掺入比、养护龄期的增长，水泥土及水泥-粉煤灰加固土的抗压强度也随之增加。 对于加固土的工程特性，本文以非线性有限元理论为基础，模拟分析水泥搅拌桩加固地基和基坑支护加固的应力和变形情况；通过两个例子分别在有处理和无处理情况下的对比，利用固化剂最佳掺入比来设计地基处理方案，并运用非线性有限元方法计算出土体内大小主应力的分布情况以及变形情况，结果表明本文所得出的配合比方案用于深层搅拌桩法来对福州地区软粘土进行地基加固时还是比较理想的，这样不仅充分利用工业废料，还可节约工程造价。更多还原

【Abstract】 Our country is vast in territory and the geological environment is complicated. Therefore, the geological conditions of the project are of diversity in different areas. All kinds of weak grounds are distributed widely, and the regionally is very obvious. So ground treatment should be conducted in terms of the local actual conditions.Through indoor routine tests, the physical and mechanical natures of intact and remolding soil of muck and mucky soil, in Fuzhou, are analyzed in this thesis. The results reveal that water content, void ratio, shear strength of remolding soil samples are lower than those of intact samples. Then qualitative analysis on the mineral composition, chemical composition and microstructure characteristic and types of the soft clay is given.Match ratio tests are done by using cement and fly-ash as curing agent, which include making soft clay with different water content into different mixing ratio cement-stabilised clay, and mixing cement and fly ash to make different cement-fly ash stengthened clay to soft clay with ascertaining water content. Afterwards unconfined compression strength is tested at different curing age. The microstructures and mechanisms of cement soil and cement-fly ash soil are studied by mean", of X-ray and scanning electron microscope(SEM) technology. The influences of the mixing amount of curing agent and curing age on the unconfined compression strength are discussed by determining the strength. By comparative study, it is concluded that the intensity of stabilized soil is the largest by using the stabilizer composed of 16% cement mixing ratio and 40% fly ash mixing amount, and it is reduced with growth of the water content of soft soil and is increased with growth of the cement mixing ratio and curing age.Based on nonlinear finite element theory, stress and deformation behaviors are analyzed after ground stabilization and foundation pit reinforcement with deep mixing method. By comparison of the conditions of treatment and non-treatment of two examples respectively, the results indicate that the match ratio scheme used for deep mixing method is more ideal when soft clay is stabilized in this area of Fuzhou in the thesis. This scheme not only can fully utilize industrial waste material, but also can economize construction cost.更多还原