Compressibility and Consolidation of Soils and Settlement Analysis

本研究计划的目的是调查和澄清有关天然土壤压缩性行为的基本问题，并开发或改进测量压缩性参数的方法，解释现场观测结果，以及分析结构沉降。需要研究的具体问题包括原生孔隙比-有效应力关系的独特性，侧压力系数的行为，沉降和孔隙压力分析的方法，以及洁净砂的二次压缩。研究方法依赖于严格的实验技术和长期的实验室和实地观测，以及数学建模和数值分析。该项目的一个显著特点是，高质量的未受干扰的天然粘土样品正在实验室研究中使用。其目的是依靠观察作为发展物理和数学模型的主要基础，并通过使用广泛的数据库和与全面建设的土壤反应进行比较来确保概念的普遍性。以往的成就证实，对固结的清晰认识是：自然土壤沉积的地质历史上的重大事件；土壤密实改良的重要机制以及在实验室或原位土壤特性测量中预期的阶段或不期望的影响。与固结有关的沉降以及相应的土体渗透性、变形性和抗剪强度的变化都是岩土工程设计、施工和结构性能中实际关注的重要因素。

The objectives of this research program are to investigate and clarify fundamental questions on compressibility behavior of natural soils and to develop or refine methods for measurement of compressibility parameters, interpretation of field observations, and analysis of settlement of structures. The specific questions to be investigated include the uniqueness of the end-of-primary void ratio-effective stress relationship, behavior of the coeffi- cient of lateral pressure, methodology for settlement and pore pressure analyses, and secondary compression of clean sands. The research method relies on exacting experimental techniques and long-term laboratory and field observations as well as mathemati- cal modeling and numerical analysis. A distinct feature of the project is that high quality undisturbed samples of natural clays are being used in laboratory investigations. The intention is to rely on observation as the primary basis for developing physical and mathematical models and to assure the generality of the concepts through the use of an extensive data base and comparisons with soil response to full-scale construction. Previous accomplishments confirm that a clear understanding of consolidation is: a significant event in the geological history of natural soil deposits; an important mechanism in soil improvement through densification; and an intended stage or an undesirable effect in laboratory or in situ measurement of soil properties. Settlements associated with consolidation and corresponding changes in permeability, deformability and shear strength of soils are all important factors of practical concern in geotechnical design, construction and performance of structures.