Experimental investigation of global backward erosion and suffusion of soils in embankment dams

Abstract

Many embankment dams constructed with a core of nonplastic or very low plasticity silt–sand–gravel (typically of glacial, fluvioglacial or alluvial origin) have experienced internal erosion. This has often expressed itself with the development of sinkholes or with intermittent episodes of increased leakage, which then reduces. In this investigation 22 soil samples with gradations representing the range of the soils used in embankment dam cores have been tested in the laboratory. All 22 soils tested were shown to be internally unstable with particle movement within the soil after placement. Some soils exhibited global backward erosion (GBE), others suffusion, and some internal instability but with no erosion from the sample, indicating self-filtering. The internal erosion process was very rapid for suffusive soils, typically occurring within minutes of test commencement, and at a gradient of 1. For soils subject to GBE and no-erosion soils, the internal movement of particles continued for weeks and months, and re-activated when the overall gradient was increased. For GBE, the erosion process occurred over a range of gradients. A method for predicting the amount of erosion and the erosion mechanism based on the gradation of the soil has been developed that is related to the ability of the soil to self-filter.

Simulation of Freeze–Thaw and Melting of Buried Ice in Longbasaba Moraine Dam in the Central Himalayas Between 1959 and 2100 Using COMSOL Multiphysics

“…Errors are smaller in summer but larger in winter, possibly because of the winter snow cover on the top surface of the dam. The thermal conductivity of snow is much smaller than that of the soil (Domine et al., 2016; Douglas et al., 2019). As snow is a poor heat conductor, the thermal insulation effect of the snow cover hinders the exchange of heat between the ground and the atmosphere and reduces the correlation between ground and air temperatures (Haeberli et al., 2017; Staub & Delaloye, 2017).…”

Internal Instability in Soils: A Critical Review of the Fundamentals and Ramifications

“…Hence, especially for the downward flow tests, other quantitative measures, such as the specimen deformation and the PSD of the dry mass collected from the effluent have been employed to determine the no-erosion state (e.g. [37,41,42,43]).…”

“…For instance, it has been experimentally shown that the size of the aperture should be 1.5 to 2 times larger than the size of the largest grains liable to move: a smaller aperture size creates bridging whereas a larger size fails to hold the sample ( 38, 39 ). Therefore, especially for the downward flow tests, other quantitative measures, such as the specimen deformation and the PSD of the dry mass collected from the effluent have been employed to determine the no-erosion state; see, for example, Bendahmane et al ( 35 ), Chang and Zhang ( 39, 40 ), and Douglas et al ( 41 ).…”

Multi-Level Hazard Detection Using a UAV-Mounted Multi-Sensor for Levee Inspection

“…Levee engineering serves as a crucial project to safeguard residents and agricultural production from the devastating impacts of flooding [1,2]. With the onset of increased rainfall during the flood season, the combined effects of floods and precipitation create substantial pressure differentials between the upstream and downstream slopes of levee structures.…”

“…Additionally, the temperature resolution capability of the thermal infrared camera at various drone flight altitudes was examined to ensure the effectiveness of data collection. (2) We annotated and constructed a dataset containing 739 sets of low-temperature targets in thermal infrared images, and applied the trained network to detect lowtemperature areas in thermal infrared images. Subsequently, the echo intensity of the LiDAR point cloud data was used to differentiate between water bodies, and assess the potential danger level of suspected hazards.…”