158
10 A Sensitivity Analysis on the Gravity …
Some mass movement processes act very slowly, while others occur suddenly.
In present laboratory experiments, an interesting phenomenon, termed compound
landslide, was observed: a group of mass failures including avalanche, mudslide,
or landslide might happen on a large, slowly slipping block. The process could last
for several minutes, or more than 10 min during a 1 h rainfall event. To distinguish
the compound landslide from other individual gravity erosion events has practical
significance. When we calculate the total amount of gravity erosion in a rainfall event,
we could calculate the volume of the compound landslide with the screenshots in
the moments before and after the longstanding landslide and need not care about
the incidents that happened on the sliding block. Surely, deviation resulted from
the hydraulic erosion still existed, but the error was so small compared to the large
landslide that it could be ignored. Figure 10.6 shows an event of compound mass
failure on the steep loess slope in the fourth rainfall of Test L5. When a large block
was sliding, two avalanches in relatively small bulk happened on the block. Because
the avalanches occurred on the slip mass during the compound landslide, the erosion
(a)
(b)
(c)
(d)
(e)
(f)
0
50(cm)
0
50(cm)
0
50(cm)
0
50(cm)
0
50(cm)
0
50(cm)
Fig. 10.6 An event of compound mass failure during the fourth rainfall of Test L5. Because the
avalanches occurred on the slip mass in the period of the compound landslide, the erosion volume
of the compound landslide was the difference of the slope volume in the white frame between a and
f. a ET was 39 26 . This is the terrain before a compound landslide. b ET was 40 32 and d ET was
41 09 . Landforms in the small white frame rectangles are those before avalanches happened. c ET
was 40 50 and e ET was 41 43 . Landforms in the small white frame rectangles are those after
avalanches happened. f ET was 42 11 . Here is the failure scar caused by the compound landslide
10 A Sensitivity Analysis on the Gravity …
Some mass movement processes act very slowly, while others occur suddenly.
In present laboratory experiments, an interesting phenomenon, termed compound
landslide, was observed: a group of mass failures including avalanche, mudslide,
or landslide might happen on a large, slowly slipping block. The process could last
for several minutes, or more than 10 min during a 1 h rainfall event. To distinguish
the compound landslide from other individual gravity erosion events has practical
significance. When we calculate the total amount of gravity erosion in a rainfall event,
we could calculate the volume of the compound landslide with the screenshots in
the moments before and after the longstanding landslide and need not care about
the incidents that happened on the sliding block. Surely, deviation resulted from
the hydraulic erosion still existed, but the error was so small compared to the large
landslide that it could be ignored. Figure 10.6 shows an event of compound mass
failure on the steep loess slope in the fourth rainfall of Test L5. When a large block
was sliding, two avalanches in relatively small bulk happened on the block. Because
the avalanches occurred on the slip mass during the compound landslide, the erosion
(a)
(b)
(c)
(d)
(e)
(f)
0
50(cm)
0
50(cm)
0
50(cm)
0
50(cm)
0
50(cm)
0
50(cm)
Fig. 10.6 An event of compound mass failure during the fourth rainfall of Test L5. Because the
avalanches occurred on the slip mass in the period of the compound landslide, the erosion volume
of the compound landslide was the difference of the slope volume in the white frame between a and
f. a ET was 39 26 . This is the terrain before a compound landslide. b ET was 40 32 and d ET was
41 09 . Landforms in the small white frame rectangles are those before avalanches happened. c ET
was 40 50 and e ET was 41 43 . Landforms in the small white frame rectangles are those after
avalanches happened. f ET was 42 11 . Here is the failure scar caused by the compound landslide