Liquefaction and Dam Failures
Liquefaction and Dam Failures
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液化和大坝溃坝
DOI：
10.1061/40512(289)20
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
A. Schofield
中科院分区：
文献类型：
--
作者：
B. Muhunthan;A. Schofield
本文基于临界状态土力学概念，即当土壤处于临界状态的干燥侧、有效应力接近零且存在高水力梯度时，就会发生液化。按照这种观点，液化是一组现象之一。包括管道化、沸腾、流态化；具有管道和通道以及水力裂缝、内部侵蚀和空隙迁移。本文将参考佩克堡、鲍德温山和提顿水坝失败的某些方面来支持这一观点。卡萨格兰德持有相反的观点，认为液化是由临界状态湿侧的沙粒之间的链式反应发生的。 Cam-clay 提供了一个比临界状态湿润的颗粒聚集体的延性稳定屈服和变形模型。这种沉积物层在变形过程中会形成褶皱。如果土壤团聚体的密度大于临界状态，它可能会因断层面而失效，其中凿岩材料膨胀和软化，或者它可能破裂并破裂成碎屑，或形成管道和通道。快速破坏的临界状态解释是孔隙水压力通过此类开放裂缝或通道快速传递。鲍德温山和提顿大坝的溃坝是由于裂缝和管道造成的。在佩克堡溃坝的情况下，我们认为来自核心水力填充物的高孔隙压力传递到了溃坝部分下方的层中；卡萨格兰德将这次失败视为连锁反应证据的观点受到质疑。讨论了填充物的选择和控制，以确保延展性并避免过度压实，以及确保稳定性的措施。
This paper is based on a critical state soil mechanics concept that liquefaction occurs when soil is on the dry side of critical states, near zero effective stress, and in the presence of high hydraulic gradients. In this view liquefaction is one of a group of phenomena; including piping, boiling, fluidization; with pipes and channels and hydraulic fractures, internal erosion and void migration. This paper will refer to some aspects of the failures of Fort Peck, Baldwin Hills, and Teton Dams in support of this view. Casagrande held an opposite view that liquefaction occurs by a chain reaction among sand grains on the wet side of critical states. Cam-clay provides a model for ductile stable yielding and deformation of an aggregate of grains wetter than critical states. A layer of such sediment can form folds during deformation. If a soil aggregate is denser than the critical state, it can fail with fault planes on which gouge material dilates and softens, or it can fracture and crack into a clastic debris, or develop pipes and channels. The critical state explanation of rapid failure is rapid transmission of pore water pressure through such opening cracks or channels. The Baldwin Hills and Teton dam failures were failures with cracks and pipes. In the case of the Fort Peck failure we suggest that high pore pressures from the core hydraulic fill were transmitted in the layer beneath the part of the dam that failed; Casagrande's view of the failure as evidence of a chain reaction is questioned. Selection and control of fills to ensure ductility and avoid over compaction and measures to ensure stability are discussed.