Unsaturated Soil Mechanics in Engineering Practice

我们认识到，我们的基础设施在很大程度上是建立在未饱和土壤上的。事实上，由于成本和工作量的降低，在非饱和土壤中施工通常是可行的。然而，岩土研究界尚未解决非饱和土理论实施的所有问题。将相对较新的非饱和土力学基本理论引入工程设计、分析和施工的主要困难之一是与非饱和土特性相关的困难、时间和成本。要将非饱和土力学和基本分析付诸实践，需要两个主要因素：(1)土壤吸力的估计或测量；(2)与土壤抗剪强度和压缩性等性能参数有关的土壤吸力的模数或系数。在这项研究中，将采用一系列复杂的方法来表征非饱和土壤。将为可能有大量支出的极高级别、大型预算项目制定分级1级。将为预算较低的常规项目制定分级4级，这些项目的测试和分析非常有限。这项研究是将非饱和土力学引入现代岩土工程和施工实践的重要一步。非饱和土理论的实施将从根本上带来更合理的分析和设计，并将在许多应用中节省大量的建筑成本。

It is recognized that our infrastructure to a very large extent is founded on unsaturated soils. In fact, construction in unsaturated soils is typically preferred when practical, due to reduced costs and effort. However, the geotechnical research community has not yet solved all of the issues of implementation of unsaturated soil theory. One of the primary difficulties in bringing the relatively new fundamental theories of unsaturated soil mechanics into engineering design, analysis, and construction is the difficulty, time, and cost associated with unsaturated soil characterization. Two major elements are needed to bring unsaturated soil mechanics and fundamental analyses into practice: (1) estimates or measurements of soil suction, and (2) moduli or coefficients relating soil suction to performance parameters such as soil shear strength and compressibility. In this research, a range in sophistication of approach will be employed for unsaturated soil characterization. Hierarchical Level 1 will be developed for extremely high-level, large budget projects for which significant expenditures are likely. Hierarchical Level 4 will be developed for lower budget, routine projects for which very limited testing and analysis are common. This research is an important step in bringing unsaturated soil mechanics into present day geotechnical engineering and construction practice. The implementation of unsaturated soils theory would result in more fundamentally sound analyses and design and would lead to substantial savings in construction costs for many applications.