Domain: Engineering — Geotechnical Engineering
Target concept: Simulation Test of Sandy Slope Reinforced with Geogrids

Video generation prompt: Sandslopes were constructed on two sand platforms. One sandslope was covered with geogrid, while the other was not. Water was simultaneously injected onto the slope crest, and the collapse conditions of both sandslopes were observed.

Evaluation guide:
(i) Target concept: Geogrid reinforcement mitigates slope failure under water infiltration by providing lateral confinement and interlocking with sand particles.
Minimum mechanism: Water must saturate the sand matrix to reduce effective stress and shear strength; geogrid must be in direct contact with sand and oriented parallel to slope surface to provide tensile restraint against particle movement.
(ii)Storyline: Frame 0–1: Two side-by-side sand slopes visible, one with planar geogrid layer on surface, one bare; water source positioned above both crests. Frame 2–3: Water stream contacts crest of both slopes simultaneously. Frame 4–7: Uncovered slope shows progressive surface slumping, grain detachment, and downward mass movement; geogrid-covered slope shows no surface disturbance: geogrid remains taut and co-planar. Frame 8–10: Collapse in uncovered slope continues to advance; geogrid-covered slope maintains original geometry, slope angle, and surface texture: no grain ejection, no crack formation, no bulging.

Manual:
Experimental Procedure
1. Construct two identical sand platforms.
2. Build two identical sandy slopes on them.
3. Cover one slope surface completely with geogrid; leave the other uncovered.
4. Simultaneously inject water at the crest of both slopes.
5. Observe collapse behavior over 10 seconds.
Observation of Experimental Phenomena
The uncovered slope collapses progressively from the crest downward, showing grain flow and loss of shape; the geogrid-covered slope retains full shape integrity with no grain displacement or surface failure.
Summary of Experimental Principles
Geogrid reinforcement increases shear resistance and confines sand particles, delaying saturation-induced failure under water infiltration.

Prompt Grounding rubric:
level_1: Fewer than two sand slopes are shown, or neither slope displays a geogrid layer at all, or the water source is never shown reaching the top (crest) of either slope, or the two slopes are never shown together in the same shot, or no water is ever released.
level_2: Two sand slopes appear, but at least one setup element is wrong: geogrid is missing from both slopes (or present on both), the two slopes are not shown on separate, comparable platforms, water is released somewhere other than the crest, or the two water streams start at clearly different times rather than together.
level_3: Two sand slopes sit side by side on their platforms in the same shot, one slope's surface is covered by a visibly grid-patterned geogrid layer while the other slope's surface is bare sand, and water is released onto the crest of both slopes.
level_4: Everything required for a 3-score is present, and in addition: the geogrid layer clearly reads as a planar grid material (not cloth, mesh netting, or debris) laid flush on the bare slope's counterpart, the two water streams begin at the crest of each slope at essentially the same moment, and the camera keeps both slopes visible together for the full video.
level_5: Everything required for a 4-score is present, and in addition: the geogrid's grid texture stays clearly legible and undisturbed by camera angle or water spray, both slopes retain their original platform position and scale throughout, and no extraneous object (tools, hands, debris) ever blocks the view of either slope's crest or surface.

Scientific and Causal Correctness rubric:
level_1: The geogrid-covered slope collapses while the uncovered slope does not (reversed outcome), or both slopes collapse identically, or neither slope responds to the water at all, or visible grain movement or slumping begins on either slope before the water stream has reached its crest.
level_2: The uncovered slope shows visible slumping while the geogrid-covered slope stays essentially intact, but the geogrid is difficult to identify as a grid material (could pass for fabric, netting, or debris), or the two water streams do not clearly land at the crest of each slope, weakening confidence that the observed difference is really due to the geogrid.
level_3: The uncovered slope visibly slumps or loses grains only after its crest is wetted, the geogrid-covered slope shows no collapse, but the match between water arrival and collapse onset is loose (a noticeable multi-frame delay, or momentary ambiguity about which slope reacts first).
level_4: The uncovered slope's collapse begins only after water reaches its crest, the geogrid-covered slope shows no collapse for the entire video, the geogrid is clearly recognizable as a rigid grid structure sitting on the slope surface, and no collapse motion of any kind precedes the corresponding slope's water contact.
level_5: Everything required for a 4-score holds, and in addition: grain flow and slumping in the uncovered slope visibly track outward and downward from the wetted crest with no interruption, the geogrid-covered slope's surface, edges, and grid pattern stay unchanged for the whole clip, and the on-screen sequence unambiguously reads as water contact causing saturation which causes collapse only where the geogrid is absent.

Spatiotemporal Consistency rubric:
level_1: A slope or its platform jumps to a different position between frames, the geogrid layer disappears or appears mid-video without being placed there, the water stream vanishes and reappears at a different spot, sand grains move upward or backward in defiance of gravity, or the lighting changes abruptly (e.g., a sudden flash or flicker) with no visible cause.
level_2: The water stream stutters or jumps between disconnected positions rather than flowing continuously from its source to the crest, one slope's geogrid flickers in and out of view, or collapsing sand shows a physically implausible motion (e.g., grains moving up-slope instead of down).
level_3: Both slopes and their platforms stay in the same fixed positions for the whole video, the geogrid stays continuously visible on its assigned slope without flicker, and the water stream reaches each crest before any grain movement appears on that slope.
level_4: Everything required for a 3-score holds, and in addition: the sliding sand grains in the uncovered slope move smoothly frame to frame with no stutter or repeated frame, the water stream's flow looks continuous rather than made of disconnected droplets, and the camera framing does not drift or re-center during the clip.
level_5: Everything required for a 4-score holds, and in addition: the collapsing sand's downward and outward motion in the uncovered slope looks physically continuous from the first grain movement to the final settled shape, the geogrid-covered slope's surface outline and grid pattern stay visibly unchanged for the whole clip, and no part of either slope, the geogrid, or the water stream is ever blocked from view by an unexplained object.