高炉矿渣粉加固上海软土地基的力学特性试验研究
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摘要
矿渣是钢铁厂生铁生产、冶炼时的副产物，矿渣的排放、堆积、处理会耗费
巨额的人力、物力和财力，既侵占土地，也带来了环境问题。因此，如何合理有
效地利用矿渣是目前国内外研究的一个热门课题。
本文针对上海地区软土的特点，采用单掺高炉矿渣微粉（GGBS）或掺高炉
矿渣微粉辅以石灰作为碱性激发剂，对上海地区软土进行固化处理，通过界限含
水量试验、三轴压缩试验、无侧限抗压强度试验、扫描电镜及电阻率测试手段，
从宏观力学指标和微观结构特性方面，研究了固化土的物理性质指标、应力-应变
关系、强度、电阻率变化规律以及固化土的微观结构特征。
本文主要研究成果为：
1. 通过界限含水量试验，得到了 GGBS 掺入量、不同配合比 GGBS-Lime 和
养护龄期对固化土的液限、塑限及塑性指数的影响规律。固化土的液限与 GGBS
的水化程度有关。GGBS-Lime 固化剂对软土的液限、塑限及塑性指数的改变较之
单掺 GGBS 固化土的改变更为明显。
2. 通过三轴压缩试验（UU）及无侧限抗压强度试验，研究了 GGBS 掺入量、
不同配合比 GGBS-Lime、养护龄期及含水量对固化土的应力-应变关系、强度、
粘聚力、内摩擦角的影响。单掺 GGBS 固化土的 GGBS 最优掺入量为 14%。当
GGBS-Lime 配合比为 GGBS：Lime=15%：5%，养护 90 天龄期时固化效果好，
且强度依然呈上升趋势。总体上 GGBS-Lime掺入比重介于 2:1~3:1时石灰对 GGBS
的碱激发效果最好，固化土强度最高。
3. 通过电阻率试验，定量分析了 GGBS 掺入量、GGBS-lime 配合比、养护龄
期对固化土电阻率的影响规律。通过不同配比、不同养护龄期试样的固化强度统
计拟合分析，得到了固化土电阻率与强度的相关关系。建立了某一电阻率与 GGBS
掺入量的固化土强度与另一已知电阻率 GGBS 掺入量固化土强度的强度相关关
系，并建立根据已知电阻率及掺入量的某 GGBS-Lime 配合比固化土的强度预测。
4. 采用扫描电镜技术，对 GGBS 固化土、GGBS-Lime 固化土的微观结构进
行了定性分析。GGBS 掺入量越高，养护龄期越长，固化土的孔隙越少、越小。
对于 GGBS-Lime 固化土，GGBS-Lime 掺入比重介于 2:1~3:1 之间，养护龄期越
长，固化土的孔隙越少，结构性越好，强度越高。
关键词：上海软土 GGBS 强度特性 电阻率 固化机理 最优配合比
ABSTRACT
Shanghai, which is Quaternary alluvial plain of the Yangtze River Delta, is typical
area of soft ground with the character of high natural water content, void ratio and
compression index within 40m in depth. Moreover, it has an obvious rheological
characteristics and rather bad engineering geological property. Using natural ground as
bearing stratum for shallow foundation is not applicable to the construction of
Shanghai area. It is one of the most important, difficult and hot issues for geotechnical
engineering to find methods of stabilizing soft soil in Shanghai.
According to the typical engineering properties of soft soil in Shanghai, the
solidification/ stabilization of soft soil using steel industry wasted materials - blast
furnace slag as main agent and lime as additives was studied in this paper. Laboratory
experiments and theoretical analysis were done to study the soil mechanics
characteristics, stress-strain relations, strength property, electrical indicators and
microstructural features of stabilized soft soil in Shanghai using GGBS.
The main findings of this article are:
(1) The influences of GGBS incorporation, GGBS-lime mix proportion and curing
time on liquid limit, plastic limit and plasticity index of stabilized soil were studied
through crucial water content coefficient test. Compared with soft soil that solely
added GGBS, the influences of GGBS-lime hardener on liquid limit, plastic limit and
plasticity index of soft soil in more obvious. Adding GGBS will cause the decline of
liquid limit and plastic limit in the early curing time. The plasticity index also declined
because the decrease amplitude of liquid limit is larger than plastic limit. With the
increases of curing time, liquid limit increased due to the slowdown of the degree of
hydration of GGBS. And plastic limit changes little, while plasticity index was
improved.
(2) The influences of GGBS incorporation, GGBS-lime mix proportion, curing
time and water content on stress-strain relations, strength property, failure strain and
internal friction angle of stabilized soil were studied through Static Triaxial Test and
Unconfined Compression Test. The stabilized soil, which was solely added GGBS, had
limited and slow growth on strength, and most of the soil samples had plastic failure
after 90d curing. The soil samples had brittle failure when it has 14d curing and
GGBS-lime mix as follows: GGBS：lime=15%:5%、GGBS：lime=10%：10%、GGBS：
lime=7%：3%. The strength is higher than 22% cement stabilized soil after 90d curing,
and keep increasing. Overall, in order to reach the best curing effect, the mixing ratio
of GGBS-Lime is supposed to between 2:1 and 3:1.
(3) The influences of GGBS incorporation, GGBS-lime mix proportion and curing
time on dynamic modulus and specific conductance index of stabilized soil through
Dynamic Modulus Test and Conductivity Test.
(4) Scanning electron microscope (SEM) was used to analysis the microstructure
of GGBS stabilized soil and GGBS-lime stabilized soil. For soil that solely added
GGBS, with higher GGBS mixing ratio and the curing time longer, the pore in the soil
is getting less and smaller. For GGBS-lime stabilized soil, with the GGBS-Lime
mixing ratio between 2:1-3:1 and the curing time longer, the porosity is less, the
structural property is better and the strength is higher than before.
Keywords: Shanghai soft soil, GGBS strength characteristic, specific
conductance, curing mechanism, best mix proportion.
目 录
摘要 ...................................................................................................................... 6
ABSTRACT.......................................................................................................... 7
目 录 .................................................................................................................. 9
第一章 绪 论....................................................................................................... 1
1.1 研究背景及意义 .................................................................................... 1
1.2 国内外的研究现状 ................................................................................ 1
1.2.1 软土特性 ..................................................................................... 1
1.2.2 矿渣的组成及其性质 .................................................................. 3
1.2.3 矿渣固化土研究现状 .................................................................. 4
1.3 存在问题 .............................................................................................. 10
1.4 论文的主要内容 .................................................................................. 11
第二章 高炉矿渣粉改良 Atterberg 界限特性研究............................................ 12
2.1 概述...................................................................................................... 12
2.2 试验概况 .............................................................................................. 12
2.2.1 试验材料 ................................................................................... 12
2.2.2 试验方案和试验方法 ................................................................ 12
2.3 试验结果分析 ...................................................................................... 13
2.3.1 GGBS 对Atterberg 界限的影响 ........................................................ 13
2.3.2 GGBS-Lime 对Atterberg 界限的影响 .............................................. 16
2.3.3 GGBS、石灰和 GGBS-Lime 对Atterberg 界限影响的对比分析 ..... 19
2.4 本章小结 .............................................................................................. 20
第三章 高炉矿渣固化土的力学特性研究 ........................................................ 22
3.1 概述...................................................................................................... 22
3.2 试验概况 .............................................................................................. 22
3.2.1 试验材料 ................................................................................... 22
3.2.2 试验方法 ................................................................................... 22
3.2.3 试验方案 ................................................................................... 25
3.3 固化土粘聚力及内摩擦角变化规律 .................................................... 26
3.3.1 养护龄期对固化土粘聚力及内摩擦角的影响.......................... 26
3.3.2 掺入量对固化土粘聚力及内摩擦角的影响 ............................. 29
3.4 固化土的无侧限抗压强度 ................................................................... 31
3.4.1 养护龄期对固化土无侧限抗压强度的影响 ............................. 31
3.4.2 掺入量对固化土无侧限抗压强度的影响 ................................. 35
3.4.3 含水量对固化土无侧限抗压强度的影响 ................................. 38
3.5 高炉矿渣粉固化土应力—应变关系.................................................... 45
3.7 本章小结 .............................................................................................. 49
第四章 矿渣固化上海软土的微观结构研究 .................................................... 51
4.1 概述...................................................................................................... 51
4.2 试验概况 .............................................................................................. 51
4.2.1 试验材料 ................................................................................... 51
4.2.2 试验方案及试验方法 ................................................................ 51
4.3 试验结果分析 ...................................................................................... 53
4.3.1 GGBS 掺入量对固化土体微观结构的影响 ............................ 53
4.3.2 养护龄期对固化土体微观结构的影响 ..................................... 54
4.3.3 GGBS-lime 固化土的微观结构变化特征 .................................. 56
4.4 本章小结 .............................................................................................. 57
第五章 高炉矿渣固化土的电学特性 ................................................................ 59
5.1 概述...................................................................................................... 59
5.2 试验概况 .............................................................................................. 59
5.2.1 试验材料 ................................................................................... 59
5.2.2 试验方案及试验方法 ................................................................ 59
5.3 试验结果及分析 .................................................................................. 60
5.3.1 养护龄期对电阻率的影响 ........................................................ 60
5.3.2 掺灰量对电阻率的影响 ............................................................ 62
5.4 基于电阻率的固化土强度预测 ........................................................... 63
5.4.1 基于电阻率 GGBS 固化土强度预测 ........................................ 63
5.4.2 基于电阻率的 GGBS-Lime 固化土强度预测 ........................... 66
5.5 本章小结 .............................................................................................. 68
第六章 结论与展望 ........................................................................................... 69
参考文献 ............................................................................................................ 72
在读期间公开发表的论文和承担科研项目及取得成果 ................................... 76
一、论文..................................................................................................... 76
二、专利..................................................................................................... 76
致 谢 ................................................................................................................ 77
第一章 绪 论
1
第一章 绪 论
1.1 研究背景及意义
矿渣是钢铁厂进行生铁生产冶炼的副产物，是高炉内分解所得的 CaO、MgO
在1400~1600℃下与铁矿石中的土质成分及焦炭中的灰分发生反应形成熔融物，
经空气或水淬急冷处理形成粒状颗粒物。
据不完全统计，我国的钢铁工业每生产 1 t 生铁，会排放高炉矿渣 0.3 t~1 t。
2012 年全国钢铁产业的粗钢产量粗略统计已超 7亿t，这些粗钢的生产过程中矿
渣的排放、堆积、处理都会耗费巨额的人力、物力和财力，既侵占土地，也带来
了环境问题。 因此，如何合理有效地利用矿渣是目前国内外研究的一个热门课题。
我国目前利用矿渣的主要途径是生产矿渣水泥及水泥混凝土掺合料、制备微晶玻
璃以及制备土壤固化剂等[1]。
随着十二五规划的顺利进行，国民经济得到快速发展，各项基础设施建设日
益兴起，高速公路、高速铁路及机场的大量建设，地基处理显得越来越重要，各
类工程对高性价比土壤固化剂的需求日趋增大。我国软土的分布十分广泛，软土
地基往往给工程施工带来诸多难题，如地基承载力不足或工程施工及使用阶段地
基沉降控制较为困难等。在软土地基的处理中，常使用波特兰水泥作为固化剂，
而在水泥生产过程中会大量排放温室气体如
2
CO
，平均生产 1 t 熟料需排放 0.95 t
2
CO
，且消耗大约 500 MJ 能量[2]。这些能量在我国主要依靠不可再生的煤炭等化
石燃料提供，而且燃烧这些化石燃料会附带其他有害气体如
2
SO
、
2
NO
及大量粉
尘的排放，带来雾霾等严重的环境问题。
研究采用高炉矿渣作为软土固化剂不仅可以降低软土地基处理的成本，同时
实现了“变废为宝”的目的，节约了能源、保护了环境，从而达到降低施工成本、
提高施工质量且兼顾绿色环保的和谐统一。
1.2 国内外的研究现状
1.2.1 软土特性
软土是淤泥和淤泥质土的总称，是在静水或非常缓慢的流水环境中沉积并经
生化作用形成 [3,4]，具有天然孔隙比大于或等于 1.0、天然含水量大于液限、孔隙
比大、压缩性高、抗剪强度低、固结系数小、固结时间长、灵敏度高、扰动性大、
透水性差、土层层状分布复杂、各层之间物理力学性质相差较大等特点。软土地
基承载力低、变形大，且一般伴随有较大的不均匀变形 ，变形稳定历时较长，在
比较深厚的软土层上，建筑物的沉降往往持续数年乃至数十年之久[5,6]。
在我国，软土的分布十分广泛[7]，表 1-1 统计显示了我国不同地质成因的软
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作者：侯斌
分类：高等教育资料
价格：15积分
属性：80 页
大小：4.39MB
格式：PDF
时间：2025-01-09
