Internal Instability of Cohesionless Soils in Upward and Downward Flow: An Experimental Verification of Theory

IF 3 3区工程技术 Q2 ENGINEERING, GEOLOGICAL

Canadian Geotechnical Journal Pub Date : 2023-11-29 DOI:10.1139/cgj-2023-0011

Maoxin Li, R. Fannin, Mark Foster, Li Yan

引用次数: 0

Abstract

Rigid-wall permeameter testing of two potentially unstable gradations established the critical hydraulic gradient to trigger instability is smaller for upward flow than for downward flow. The experimental finding is explained with reference to the Skempton-Brogan stress reduction factor α in the finer fraction content of the soil. Theory uses the α-factor to define a hydro-mechanical envelope in gradient-stress space that is independent of flow direction, and the experimental results are found in good agreement with the theory. Testing with upward flow is recommended to determine the value of α for an internally unstable gradation because, in contrast to downward flow, there is no requirement for an outflow boundary.

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无粘性土壤在向上和向下流动时的内部不稳定性：理论的实验验证

对两种潜在不稳定级配进行的刚性壁渗透仪测试表明，向上流动引发不稳定的临界水力梯度小于向下流动。这一实验结果的解释参考了土壤中较细组分含量的 Skempton-Brogan 应力降低系数 α。理论上，α 因子定义了梯度应力空间中的水力机械包络，该包络与流动方向无关。建议采用向上流动的测试方法来确定内部不稳定梯度的 α 值，因为与向下流动不同，不需要外流边界。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Canadian Geotechnical Journal 地学-地球科学综合

CiteScore

7.20

自引率

5.60%

发文量

163

审稿时长

7.5 months

期刊介绍： The Canadian Geotechnical Journal features articles, notes, reviews, and discussions related to new developments in geotechnical and geoenvironmental engineering, and applied sciences. The topics of papers written by researchers and engineers/scientists active in industry include soil and rock mechanics, material properties and fundamental behaviour, site characterization, foundations, excavations, tunnels, dams and embankments, slopes, landslides, geological and rock engineering, ground improvement, hydrogeology and contaminant hydrogeology, geochemistry, waste management, geosynthetics, offshore engineering, ice, frozen ground and northern engineering, risk and reliability applications, and physical and numerical modelling. Contributions that have practical relevance are preferred, including case records. Purely theoretical contributions are not generally published unless they are on a topic of special interest (like unsaturated soil mechanics or cold regions geotechnics) or they have direct practical value.