越流系统中成层结构性弱透水土层一维固结理论研究

发布时间：2018-12-12 05:14

【摘要】：在我国沿海沿江地区,普遍分布着深厚的软粘土层。当抽取地下水时,这些弱透水性的软土层与抽水层之间形成水力梯度差,发生水力联系现象,即越流。越流引发弱透水土层的固结,导致地面沉降。而弱透水土层在形成过程中,往往受沉积力、沉积环境及土颗粒间胶结作用等的影响,大部分都具有结构性。在固结过程中,考虑结构性与不考虑结构性相比,会有很大的差异。在准确预测抽水引发的地面沉降中,这种差异性是不能忽略的。为此,本文采用解析法对越流系统中成层结构性弱透水土层一维固结理论及其固结性状开展了较深入的研究。主要原创性工作如下： 1.基于双层地基一维固结理论,采用简化的kv-σ和mv-σ分段模型表征软土结构性参数变化,建立了以水头表示的单层结构性软土一维固结控制方程。分别推导了承压含水层水位曲线下降、瞬时和线性下降情况,弱透水土层中水头、孔隙水压、沉降及按沉降定义的平均固结度的解析表达式,并验证了当不考虑结构性时的本文解析解与已有解析解的一致性。结合不同算例,分析了结构性及结构性的强弱对固结性状的影响。 2.分别推导了潜水层和承压水层水位下降引发的双层结构性软土层一维固结解析解。通过计算,阐明了水位下降与荷载作用下引发结构性软土固结之间关系的实质,并分析了结构性及结构性的强弱对固结性状的影响,进一步对比了上下土层结构屈服应力值的相对大小对固结度和沉降的影响。 3.推导了承压水层水位下降引发的成层结构性弱透水土层一维固结解析解。分析了结构性及结构性的强弱对水头、孔隙水压、沉降及沉降发展速率的影响,并探讨了夹层土结构屈服应力的不同对固结度和沉降的影响。
[Abstract]:In the coastal areas along the Yangtze River, deep soft clay layers are widely distributed in China. When the groundwater is extracted, the hydraulic gradient difference is formed between the weak permeable soft soil layer and the pumping layer, and the phenomenon of hydraulic connection occurs, that is, the overflowing. The overflows lead to the consolidation of the weak permeable soil, which results in the settlement of the land. In the process of formation, the weak permeable soil layer is often affected by sedimentary force, sedimentary environment and cementation between soil particles, most of which are structural. In the process of consolidation, there is a great difference between considering the structure and not considering the structure. This difference can not be ignored in accurately predicting the land subsidence caused by pumping water. Therefore, in this paper, the one-dimensional consolidation theory and its consolidation behavior of stratified structural weak permeable soil layer in the cross flow system are studied by analytical method. The main original works are as follows: 1. Based on the one-dimensional consolidation theory of double-layer foundation, the simplified kv- 蟽 and mv- 蟽 piecewise models are used to characterize the structural parameters of soft soil, and the one-dimensional consolidation control equation of single-layer structural soft soil is established in terms of water head. The analytical expressions of water level curve, instantaneous and linear decline, water head, pore water pressure, settlement and average degree of consolidation defined by settlement in weak permeable soil are derived, respectively. The consistency between the analytic solution and the existing analytic solution is verified when the structure is not considered. Combined with different examples, the influence of structural and structural strength on consolidation characteristics was analyzed. 2. The one-dimensional consolidation analytical solution of double-layered soft soil caused by the drop of water level in submersible layer and confined water layer is derived respectively. In this paper, the essence of the relationship between the fall of water level and the consolidation of structural soft soil caused by load is clarified, and the influence of structural and structural strength on consolidation behavior is analyzed. The effects of yield stress on consolidation and settlement of upper and lower soil layers are further compared. 3. In this paper, the analytical solution of one dimensional consolidation of layered structural weak permeable soil caused by water level drop in confined water layer is derived. The influence of structural and structural strength on water head, pore water pressure, settlement and settlement development rate is analyzed, and the influence of different yield stress of intercalated soil structure on consolidation degree and settlement is discussed.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43

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