Early studies on the 1953 North Sea floods showed that desiccation fissuring of clay fill can play a major role in the failure of flood embankments under overflow conditions. However, the onset of desiccation fissuring in embankments and its contribution towards breach initiation has not been fully researched. Field and laboratory studies were thus carried out into the desiccation fissuring of clay flood embankments in the UK. The work found that a critical condition is reached when desiccation creates an interconnected network of sub-vertical and sub-horizontal fissures, which significantly increases the mass permeability of the fill material and hence allows rapid seepage of flood water through the surface layer of the embankment. It is suggested high rates of seepage cause localised uplifting of clay blocks, leading to progressive slope failure and successive breaching. Small-scale desiccation tests carried out on discs of soil in pressure plates showed very good agreement between the onset of cracking in the pressure plates and the moisture content recorded in the field. This suggests that it is possible to assess the susceptibility of a fill material to desiccation fissuring from the soil water characteristic curve

The study of desiccation cracks in soils has been a subject of increasing attention in recent research. This paper presents the use of a 2D profile laser that is coupled with a motion controller (that allows scanning the overall surface of a drying soil) and electronic balance (to measure the water loss). The aim is to accurately track the three most relevant variables associated with the behavior 14 of soils during desiccation: volume change, water loss and evolving crack network’s morphology. The paper presents the methodology to obtain a digital model of the soil using the experimental setup described above. The main results of a natural soil subjected to drying are presented and discussed, including evolution of cracks aperture; evolution of cracks depth, surface contour levels (at different times); and evolution of volume change. It is shown that the proposed methodology provides very useful information for studying the behavior of soils subjected to desiccation

This article describes a miniaturised electrical imaging (resistivity tomography) technique to map the cracking pattern of a clay model. The clay used was taken from a scaled flood embankment built to study the fine fissuring due to desiccation and breaching process in flooding conditions. The potential of using a miniature array of electrodes to follow the evolution of the vertical cracks and number them during the drying process was explored. The imaging technique generated two-dimensional contoured plots of the resistivity distribution within the model before and at different stages of the desiccation process. The change in resistivity associated with the widening of the cracks were monitored as a function of time. Experiments were also carried out using a selected conductive gel to slow down the transport process into the cracks to improve the scanning capabilities of the equipment. The main vertical clay fissuring network was obtained after inversion of the experimental resistivity measurements and validated by direct observations

Highlights  ERT analysis of desiccation cracks in flood embankment during different seasons.  Forward modelling of small and large fissuring networks.  Validation of 2-D and 3-D miniature arrays on fissured flood embankment.  Evaluation of standard ERT arrays on large section of flood embankment.  Validation of field result with forward modelling.