چكيده به لاتين
During an earthquake, the differential movement of the fault sides causes the earth's surface to rupture, leading to significant damage to both surface and subsurface structures near the fault. Past researchs have primarily focused on superstructures, such as surface foundations and tunnels, and strategies to mitigate the associated risks. While there are some numerical studies investigating fault path propagation in earthen dams, there is a lack of comprehensive laboratory studies on this topic.
This research examines the propagation of fault paths within earthen dams that have clay cores, both with and without cutoff walls, under reverse and normal faulting conditions. Key factors discussed include alluvial thickness, the location where the fault intersects the dam body, overburden water pressure, the alignment of the fault path with the dam, and the presence of the cutoff wall. Additionally, the interaction between normal and reverse faults, as well as the behavior of cemented dams (CMD), is explored.
The findings for reverse faulting indicate that earthen dams experience horizontal, vertical, and rotational displacement, and sometimes distortion in the core, although no cracks were observed in the core during laboratory tests. Observations suggest that the free height of the dam reservoir decreases by up to 90% in response to vertical displacement caused by faulting. Furthermore, increased water pressure can lead to plastic strain in the core. Image processing and numerical modeling reveal that strains develop in the area between the crust and the alluvial foundation due to faulting.
In contrast to reverse faulting, complete rupture of the core has been observed when the normal fault path intersects it, even with vertical displacements of less than 1 meter. After the fault path penetrates the clay core and passes through the alluvial foundation, the fault angle increases due to changes in material hardness, and then decreases as it moves into the filter and shell. Additionally, the dam wall influences the fault path direction; at low fault displacements, it can divert the fault toward the core, leading to complete dam rupture.
Overall, the behavior of CMD dams under normal and reverse faults resembles that of surface foundations. Fault impacts at various points on the dam result in substantial rotation and displacement in dams constructed with cemented materials, with recorded exceeding 10 degrees for vertical displacements greater than 2 meters.
