加固处理后的吹填土次固结特性研究
发布时间：2018-07-21 15:56
【摘要】：吹填软土是一种近些年才出现的人工成因软土,其经加固处理后次固结特性依旧存在,由次固结导致的工后沉降对建筑工程的正常使用及后期维护影响重大。目前对于加固处理后吹填软土的次固结研究相对较少,且研究手段多通过单纯的室内人工模拟试验来进行,难以较准确的反映实际状况。本研究以天津港东疆港区某工程项目为依托,借助先进的全自动数据采集固结仪系统,进行了一系列不同方案的一维固结试验,对加固处理后吹填软土的固结、次固结特性及各种影响因素进行了深入研究,并运用数理统计方法,以足量试验数据的算术平均值作为研究依据,减小误差,提高可信度,使研究结果更贴实际,为减少及预防加固处理后吹填软土的工后沉降提供依据及建议,亦为类似问题的研究思路及方法提供参考与借鉴。本研究通过对真空预压加固处理后的吹填软土与同区域下覆的成份基本相同的自然海相沉积软土的工程特性比较,探讨两种土的物理、强度、固结特性的异同、产生的原因及可能带来的后果,揭示了次固结系数随荷载变化的特征,提出这种特征是原状土的基本特征,具有普适性。并发现加固处理后吹填软土在一维固结试验中具有首级荷载下固结系数偏大,后随着荷载的增加固结系数逐渐减小并趋于常值的现象,提出含水率大于40%的各类饱和原状软土亦有此种现象,并进行了解释。分别采用0.5、1.0、3.0的不同加载比固结试验,研究了加载速率的不同对加固处理后吹填软土的固结系数、次固结系数的影响、影响程度及适用条件,提出在荷载总量一定的情况下,采用适当的小增量多批次的加载方式进行软基加固可改善加固效果,减少次固结沉降。并发现采用过小的加载比,会使其固结系数、次固结系数与荷载的关系曲线出现波浪起伏现象,表明其主、次固结沉降速率随荷载的施加出现或大或小的不均匀现象,并解释了原因。通过不同厚度的一维固结试验探讨了排水路径对加固处理后吹填软土的主、次固结的影响,及影响程度,并从理论公式角度进行了解释。通过两个回次的超载预压及卸载回弹试验,探讨了超载预压、重复超载预压及卸荷回弹对加固处理后吹填软土的主、次固结的影响,提出超载预压、重复的超载预压可有效降低次固结沉降。
[Abstract]:Filling soft soil is a kind of artificial soft soil that appeared only in recent years. The secondary consolidation characteristics still exist after reinforcement treatment. The post-construction settlement caused by secondary consolidation has a great impact on the normal use and later maintenance of building engineering. At present, there are few researches on secondary consolidation of dredged soft soil after reinforcement and treatment, and most of the research methods are carried out by simple indoor artificial simulation test, so it is difficult to accurately reflect the actual situation. Based on an engineering project in Dongjiang Port area of Tianjin Port, this study carried out a series of one-dimensional consolidation tests of different schemes with the help of advanced fully automatic data acquisition and consolidation instrument system, and the consolidation of soft soil after reinforcement and treatment was carried out. In this paper, the secondary consolidation characteristics and various influencing factors are studied in depth, and the arithmetic average of sufficient experimental data is used as the research basis by using mathematical statistics method. The error is reduced, the reliability is improved, and the research results are more practical. In order to reduce and prevent post-construction settlement of soft soil after reinforcement and treatment, it also provides reference and reference for the research ideas and methods of similar problems. Based on the comparison of the engineering characteristics of the soft soil filled by vacuum preloading and the natural marine sedimentary soft soil which has the same composition under the same area, the similarities and differences of the physical, strength and consolidation characteristics of the two soils are discussed. The causes and possible consequences reveal the variation of the secondary consolidation coefficient with the load. It is suggested that this characteristic is the basic feature of the undisturbed soil and has universal applicability. It is also found that the consolidation coefficient is larger under the first load and then decreases gradually with the increase of the load and tends to the constant value in the one-dimensional consolidation test. This phenomenon is also found in all kinds of saturated undisturbed soft soils with moisture content greater than 40%, and the explanation is given. The effects of different loading rates on the consolidation coefficient, secondary consolidation coefficient, influence degree and applicable conditions of soft soil after reinforcement are studied by using the different loading ratios of 0.5 and 1.0% 3.0 respectively. It is put forward that under the condition of constant load total amount, the effect of loading rate on the consolidation coefficient, secondary consolidation coefficient and application condition of soft soil after reinforcement treatment are studied. Using appropriate small increment multi-batch loading method to strengthen soft foundation can improve the reinforcement effect and reduce the secondary consolidation settlement. It is also found that if the loading ratio is too small, the wave fluctuation will occur in the curve of consolidation coefficient, secondary consolidation coefficient and load, indicating that the settlement rate of the main and secondary consolidation occurs with the application of the load or the phenomenon of large or small non-uniformity. And explained the reason. The influence of drainage path on the main and secondary consolidation of soft soil after consolidation and treatment is discussed through one-dimensional consolidation tests with different thickness, and the influence degree is explained from the point of view of theoretical formula. In this paper, the effects of overload preloading, repeated overload preloading and unloading rebound on the main and secondary consolidation of soft soil after reinforcement and treatment are discussed through the overloading preloading and unloading springback tests, and the overload preloading is put forward. Repeated overload preloading can effectively reduce the secondary consolidation settlement.
【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】：TU447
本文编号：2136029
[Abstract]:Filling soft soil is a kind of artificial soft soil that appeared only in recent years. The secondary consolidation characteristics still exist after reinforcement treatment. The post-construction settlement caused by secondary consolidation has a great impact on the normal use and later maintenance of building engineering. At present, there are few researches on secondary consolidation of dredged soft soil after reinforcement and treatment, and most of the research methods are carried out by simple indoor artificial simulation test, so it is difficult to accurately reflect the actual situation. Based on an engineering project in Dongjiang Port area of Tianjin Port, this study carried out a series of one-dimensional consolidation tests of different schemes with the help of advanced fully automatic data acquisition and consolidation instrument system, and the consolidation of soft soil after reinforcement and treatment was carried out. In this paper, the secondary consolidation characteristics and various influencing factors are studied in depth, and the arithmetic average of sufficient experimental data is used as the research basis by using mathematical statistics method. The error is reduced, the reliability is improved, and the research results are more practical. In order to reduce and prevent post-construction settlement of soft soil after reinforcement and treatment, it also provides reference and reference for the research ideas and methods of similar problems. Based on the comparison of the engineering characteristics of the soft soil filled by vacuum preloading and the natural marine sedimentary soft soil which has the same composition under the same area, the similarities and differences of the physical, strength and consolidation characteristics of the two soils are discussed. The causes and possible consequences reveal the variation of the secondary consolidation coefficient with the load. It is suggested that this characteristic is the basic feature of the undisturbed soil and has universal applicability. It is also found that the consolidation coefficient is larger under the first load and then decreases gradually with the increase of the load and tends to the constant value in the one-dimensional consolidation test. This phenomenon is also found in all kinds of saturated undisturbed soft soils with moisture content greater than 40%, and the explanation is given. The effects of different loading rates on the consolidation coefficient, secondary consolidation coefficient, influence degree and applicable conditions of soft soil after reinforcement are studied by using the different loading ratios of 0.5 and 1.0% 3.0 respectively. It is put forward that under the condition of constant load total amount, the effect of loading rate on the consolidation coefficient, secondary consolidation coefficient and application condition of soft soil after reinforcement treatment are studied. Using appropriate small increment multi-batch loading method to strengthen soft foundation can improve the reinforcement effect and reduce the secondary consolidation settlement. It is also found that if the loading ratio is too small, the wave fluctuation will occur in the curve of consolidation coefficient, secondary consolidation coefficient and load, indicating that the settlement rate of the main and secondary consolidation occurs with the application of the load or the phenomenon of large or small non-uniformity. And explained the reason. The influence of drainage path on the main and secondary consolidation of soft soil after consolidation and treatment is discussed through one-dimensional consolidation tests with different thickness, and the influence degree is explained from the point of view of theoretical formula. In this paper, the effects of overload preloading, repeated overload preloading and unloading rebound on the main and secondary consolidation of soft soil after reinforcement and treatment are discussed through the overloading preloading and unloading springback tests, and the overload preloading is put forward. Repeated overload preloading can effectively reduce the secondary consolidation settlement.
【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】：TU447
【参考文献】
相关期刊论文 前10条
1 雷华阳;王学超;丁小冬;刘景锦;陈丽;张文振;;软土主次固结划分及影响因素探讨[J];工程地质学报;2014年03期
2 韩鹏;朱平;张文振;陈少青;;灰色GM(1,l)和Verhulst模型在吹填土地基沉降中的应用[J];港工技术;2014年01期
3 武亚军;覃萍;杨建波;;真空荷载下超软土固结试验及土颗粒移动数值模拟研究[J];水运工程;2013年09期
4 孙立强;杨爱武;刘润;邱长林;;新近吹填土固结系数为变量的固结方程研究[J];工程地质学报;2013年03期
5 王蕊颖;王清;张颖;项良俊;;基于时间序列—动态神经网络吹填土沉降预测研究[J];工程地质学报;2013年03期
6 邱长林;闫澍旺;孙立强;纪玉诚;;孔隙变化对吹填土地基真空预压固结的影响[J];岩土力学;2013年03期
7 宋晶;王清;张鹏;江小亮;;高黏性吹填土固结过程中细颗粒迁移规律研究[J];工程地质学报;2012年06期
8 仇玉良;丁洲祥;;一维小变形主、次固结耦合理论模型分析[J];岩土力学;2012年07期
9 孟静;王云龙;;北京平原区软弱黏性土次固结系数的试验研究[J];工程地质学报;2012年03期
10 楼晓明;李德宁;杨敏;;上海地区基坑底部粉质黏土回弹变形参数分析[J];同济大学学报(自然科学版);2012年04期
相关硕士学位论文 前1条
1 王冠英;不同地区海积软土前期固结压力与结构强度的关系及其成因分析[D];吉林大学;2004年
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