Coupled Solid-Deformation/Fluid-Flow Simulation of Failure Initiation in Variably Saturated Slopes

变饱和斜坡中失效萌生的固体变形/流体流动耦合模拟

• 批准号: 0824440
• 负责人: Ronaldo Borja
• 金额: $ 28.53万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0824440&HistoricalAwards=false
• 关键词: Coupled; Solid; Deformation; Fluid; Flow

Landslides occur when earth material moves rapidly downhill after failing along a shear zone. Debris flows are differentiated from landslides by the pervasive, fluid-like deformation of the mobilized material. Landslides and debris flows threaten lives and property worldwide. Despite the fact that good progress has been made within the last two decades relative to understanding hydrologically-driven slope failure, important research has yet to be conducted in 3D physics-based fluid flow and hydrologically-driven slope instability in variably saturated soils. This award funds interdisciplinary research focused on a physics-based characterization of coupled hydrologic response/slope stability processes for steep hillslopes at the catchment scale. The model will couple solid deformation with fluid flow processes in variably saturated soils, as well as quantify the exchange of water between the subsurface and surface continua. This allows us to better understand the effects of surface runoff, evapotranspiration, and percolation on the spatial and temporal variations of degree of saturation, effective stress, and deformation pattern within the variably saturated slope. The coupled model will be tested with comprehensive and exhaustive data from the Coos Bay experimental catchment (CB1), as well as with the numerical results of recently conducted simulations on the same catchment using an Integrated Hydrology Model (InHM). This research will also utilize a recently developed stabilized low-order finite element approximation scheme employing equal orders of interpolation for the solid displacement and pore pressure fields. The highly instrumented CB1 slope failed as a large debris flow in November 1996, thus providing large volumes of data with which to compare the model predictions.The research team will combine expertise in geotechnical engineering, computational geomechanics, and quantitative hydrogeomorphology available at Stanford University to develop and test a physics-based model of slope failure initiation. To the knowledge of the PIs, no slope failure initiation model currently exists in the literature that addresses the effect of variable saturation in a quantitative way. We believe that the FE method has reached such an advanced stage that it can now handle not only complex geometry but also the effect of variable saturation. A further intellectual merit of this research lies in the tremendous opportunity for testing and validation of the proposed mathematical approaches with the available data set. The CB1 data set allows model testing and validation on a large-scale slope with complex topography and variable saturation. The availability of high-quality hydrological and geotechnical data for CB1 will help constrain the parameters of the problem, thus providing tremendous opportunity to gain a better understanding of the important processes controlling slope instability.The study is a timely contribution towards an improved understanding of the processes that control slope instability in a system driven by a rigorous characterization of the near-surface hydrology and soil constitutive properties. The simulation effort will effectively demonstrate the utility and/or limits of physics-based slope stability models less comprehensive than the one to be developed here for field conditions similar to CB1. The proposed research will also utilize the advances in computational fluid dynamics for application to geotechnical and geosciences problems. Both PIs are seriously committed to ensuring full involvement of undergraduate and underrepresented students in this project. This can be gleaned from their proven track record of mentoring, advising, supervising, and graduating undergraduate and underrepresented students at Stanford.

当沿剪切带失败后，地球物质在迅速下坡时，会发生滑坡。 碎屑流与动员材料的普遍流体样变形不同于滑坡。 滑坡和碎屑流动威胁着世界各地的生命和财产。 尽管相对于理解水文驱动的坡度故障，在过去的二十年中已经取得了良好的进步，但在3D物理学的流体流量和在变化饱和的土壤中，重要的研究尚未进行。该奖项为跨学科研究提供了介绍，该研究的重点是基于物理的表征，该研究对陡峭的山坡在集水量表上的水文反应/坡度稳定过程进行了耦合。 该模型将固体变形与多种饱和土壤中的流体流动过程相结合，并量化地下和表面连续性之间的水交换。 这使我们能够更好地理解表面径流，蒸散性以及渗透对可变饱和坡度内饱和度，有效应力和变形模式的空间和时间变化的影响。 耦合模型将通过COOS BAY实验集水区（CB1）的全面和详尽的数据进行测试，以及使用集成水文模型（INHM）在同一集水区进行了最近进行的模拟的数值结果。 这项研究还将利用最近开发的稳定的低阶有限元近似方案，该方案采用固体位移和孔隙压力场的插值相等。 高度仪器的CB1斜率在1996年11月作为大量碎片流失败，因此提供了大量数据来比较模型预测。研究团队将在Geotechnical工程，计算地球力学，计算地球力学和定量的Hydrophology中相结合的专业知识，可在Stanford University使用STANFORD UNIVESSION可开发和测试SLOPE FAIMAPE模型的模型。 为了了解PI，文献中目前尚无斜率故障启动模型，该模型以定量方式解决了可变饱和的效果。 我们认为，FE方法已经达到了一个高级阶段，以至于现在不仅可以处理复杂的几何形状，还可以处理可变饱和的效果。 这项研究的进一步智力优点在于，使用可用的数据集测试和验证拟议的数学方法的巨大机会。 CB1数据集允许在具有复杂地形和可变饱和度的大规模斜率上进行模型测试和验证。 CB1的高质量水文和岩土技术数据的可用性将有助于限制问题的参数，从而提供了巨大的机会，以更好地了解控制斜坡不稳定性的重要过程。该研究是对在严格的近似构图中对系统驱动的过程驱动的进程的及时理解，这些过程受到了近乎构造的构图和土壤的构成型和土壤的构成和土壤的构成。 模拟工作将有效地证明基于物理的坡度稳定性模型的效用和/或限制，而不是在此类似于CB1的现场条件下开发的效用和/或限制。 拟议的研究还将利用计算流体动力学的进步，以应用于岩土技术和地球科学问题。 这两个PI都非常致力于确保本科生和代表不足的学生完全参与该项目。 这可以从他们在斯坦福大学的指导，建议，监督和毕业的本科生和毕业生的学生中获得的可靠记录来收集到这一点。