【作者】 严栋；

【导师】 蒋关鲁；

【作者基本信息】 西南交通大学 ， 道路与铁道工程， 2008， 硕士

【摘要】 本文主要结合“客运专线深厚非饱和土的沉降特性及地基处理技术”的实际研究工作,以客运专线胶济铁路四线的处于非饱和土状态的地基土粉质粘土与粉土的沉降特性为研究对象,通过采用现场载荷试验,静力触探试验,标准贯入试验,旁压试验,室内固结(压缩变形)试验,三轴压缩试验,以及进行现场沉降观测等一系列试验方法,来总结处于非饱和状态的地基土沉降变形性状,对其沉降规律进行研究,从而得出非饱和土的沉降变形特性,进而来预测地基的变形,并将计算结果与实测结果进行对比和分析,进而印证了本文提出的计算方法的可行性。主要研究成果如下:①通过一系列现场原位测试试验,详细查明了粉土和粉质粘土的工程地质特性及基本物理力学特性;②通过室内固结(压缩变形)试验,三轴压缩试验来分析这两类土的固结变形与时间的关系,得到了在侧限条件下,粉土和粉质粘土的应力与应变的变化关系符合双曲线模式,粉土的轴向应变与时间的关系符合成长型曲线(“S”曲线)模式,粉质粘土的轴向应变与时间的关系符合双曲线模式。③结合室内压缩试验的应力与应变关系,详细分析了路基沉降机理,提出了计算地基最终沉降量的方法(改进的分层总和法),并与实测结果对比分析,此方法较接近于实际,具有其可行性。④通过现场沉降观测,分析路堤荷载作用下的地基沉降,研究在路堤填筑期间的沉降变形规律,并通过填筑期间的实测数据来预测地基最终沉降量;⑤通过大量实测数据分析,得出了非饱和粉质粘土和粉土的沉降变形特性规律,为进一步研究其沉降变形理论提供可靠的科学依据。更多还原

【Abstract】 According to the study on the settlement characteristic and foundation treatment technique of unsaturated silt and silty clay subsoil between Qingdao and Jinan special passenger train, a series of tests have been carried out, such as filed plane loading test, static cone penetration test, standard penetration test, lateral pressure meter test, standard indoor consolidation test, triaxial compression test and field settlement observation. Through a series of tests the settlement characteristic of unsaturated subsoil can be generalized and the settlement pattern can be obtained. From the settlement pattern the deformation of subgrade can be pre-estimated. According to comparison analysis of the results of between the calculation and the field observation, further the calculation method put forward is available. Some results can be generalized as followings:(1) Through a series of field test, the engineering geology and basic physical and mechanic characteristic of silt and silty clay subsoil can be surveyed particularly.(2) Through indoor consolidation test and triaxial compression test, the consolidation characteristic relationship of the silt and silty clay subsoil can be analysed. On the condition of lateral confinement, the relationship of between stress and strain of silt and silty clay fits the hyperbola pattern. The relationship of between strain and time of silt fits ’S’ curve pattern. The relationship of between strain and time of silty clay fits hyperbola pattern.(3) According to the stress and strain relationship of indoor consolidation test, and analysis of the mechanism of subgrade settlement, the method of calculation of the ultimate settlement is put forward. Comparison analysis of results between the field test and modified calculation methods, the modified calculation method is confirmed to be available.(4) Through field settlement observation, the settlement law under embankment load was studied. According to the field settlement data in the course of fillings the ultimate settlement can be pre-estimated.(5) Through the analysis of lots of field settlement data, the settlement characteristic of the unsaturated silt and silty clay is obtained. The settlement theory should be further studied dependent on the settlement charchateristic.更多还原