真空负压作用下新近吹填超软土固结机理研究

Compared with the natural soft soil foundation, the stable soil structure has not been formed in the surface layer, and it is fluxible for the fresh filled ultra-soft soil. Because the local compactness part is serious after the consolidation by vacuum preloading, the average bearing capacity of foundation could not satisfy the design requirements, and the effects of consolidation is not perfect. The pore water flowing mode in fresh filled ultra-soft soil is turbulent current or clay-water mixed under the vacuum negative pressure, and the prediction results of foundation settlement and consolidation time is obviously different from the practical situation by utilizing the classical consolidation theory. It is difficult to discribe the progress of the consolidation and deformation. So the adoption of the consolidation by vacuum preloading is purposeless. Based on analyzing the particle composition, mineral composition and engineering properties of typical fresh filled ultra-soft soil, the limitation of the existing theory about seepage and consolidation in soil mechanics will be breakthroughed in this research. By adopting the turbulence theory, the new types of hydraulic physical model experiments will be designed, and the particle starting and control mechanism of the fresh filled ultra-soft soil under the vacuum negative pressure will be analyzed. The rules of deposition and consolidation will be discussed for the fresh filled ultra-soft soil under the vacuum negative pressure, and the control equation which could discribe the consolidation progress will be built. The preliminary consolidation theory of the fresh filled ultra-soft soil under the vacuum negative pressure will be formed. Therefore the achievements of this research could provide the theoretical support to resolve the application issues of basic theory for the foudation vacuum preloading of the fresh filled ultra-soft soil.

与天然软土地基相比，新近吹填超软土浅表层尚未形成稳定土体结构，具有流动性，真空预压加固后出现严重的局部密实现象，地基平均承载力达不到设计要求，加固效果不理想。因真空负压作用下孔隙水的流动呈紊流状态或泥水混合流，采用经典固结理论预测新近吹填超软土地基沉降量及固结时间与实际情况差异较大，难以描述其固结变形规律，使得该技术的应用存在较大盲目性。针对上述关键科学问题，在深入分析典型新近吹填超软土颗粒组成、矿物成分及工程性质的基础上，突破现有土力学渗流和固结理论的局限性，引入紊流理论，设计新型水力学物理模型试验，重点分析真空负压作用下新近吹填超软土颗粒起动及控制机理，研究新近吹填超软土在真空负压作用下的沉积固结规律，建立能够反映真空吸力作用下新近吹填超软土沉积固结规律的固结控制方程，初步形成新近吹填超软土在负压作用下的固结理论，为新近吹填超软土地基真空预压提供理论支撑，以解决相关的基础理论应用问题。

与天然软土地基相比，新近吹填超软土浅表层尚未形成稳定土体结构，具有流动性，真空预压加固后出现严重的局部密实现象，地基平均承载力达不到设计要求，加固效果不理想。因真空负压作用下孔隙水的流动呈紊流状态或泥水混合流，采用经典固结理论预测新近吹填超软土地基沉降量及固结时间与实际情况差异较大，难以描述其固结变形规律，使得该技术的应用存在较大盲目性。针对上述关键科学问题，在深入分析典型新近吹填超软土颗粒组成、矿物成分及工程性质的基础上，突破现有土力学渗流和固结理论的局限性，引入紊流理论，设计新型水力学物理模型试验，重点分析真空负压作用下新近吹填超软土颗粒起动及控制机理，研究新近吹填超软土在真空负压作用下的沉积固结规律，建立能够反映真空吸力作用下新近吹填超软土沉积固结规律的固结控制方程，初步形成新近吹填超软土在负压作用下的固结理论，为新近吹填超软土地基真空预压提供理论支撑，以解决相关的基础理论应用问题。.本项目开展了“真空负压作用下新近吹填超软土固结机理研究”，研究在深入分析典型新近吹填超软土颗粒组成、矿物成分及工程性质的基础上，突破现有土力学渗流和固结理论的局限性，引入紊流理论，设计新型水力学物理模型试验，重点分析真空负压作用下新近吹填超软土颗粒起动及控制机理，研究新近吹填超软土在真空负压作用下的沉积固结规律，建立能够反映真空吸力作用下新近吹填超软土沉积固结规律的固结控制方程，形成新近吹填超软土在真空负压作用下的固结理论，为新近吹填超软土地基真空预压提供理论支撑，以解决相关的基础理论应用问题。