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Analysis on Two Typical Landslide Hazard Phenomena in The Wenchuan Earthquake by Field Investigations and Shaking Table Tests.

Yang C, Zhang J, Liu F, Bi J, Jun Z - Int J Environ Res Public Health (2015)

Bottom Line: Considering the above disaster phenomena, the reasons are analyzed based on shaking table tests of one-sided, two-sided and four-sided slopes.The analysis results show that: (1) the amplifications of the peak accelerations of four-sided slopes is stronger than that of the two-sided slopes, while that of the one-sided slope is the weakest, which can indirectly explain the phenomena that the damage is most serious; (2) the amplifications of the peak accelerations gradually increase as the slope angles increase, and there are two inflection points which are the point where the slope angle is 45° and where the slope angle is 50°, respectively, which can explain the seismic phenomenon whereby landslide hazards mainly occur on the slopes whose slope angle is bigger than 45°.The amplification along the slope strike direction is basically consistent, and the step is smooth.

View Article: PubMed Central - PubMed

Affiliation: School of Civil Engineering, Key of Transportation Tnuuel Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China. yangchangwei56@163.com.

ABSTRACT
Based on our field investigations of landslide hazards in the Wenchuan earthquake, some findings can be reported: (1) the multi-aspect terrain facing empty isolated mountains and thin ridges reacted intensely to the earthquake and was seriously damaged; (2) the slope angles of most landslides was larger than 45°. Considering the above disaster phenomena, the reasons are analyzed based on shaking table tests of one-sided, two-sided and four-sided slopes. The analysis results show that: (1) the amplifications of the peak accelerations of four-sided slopes is stronger than that of the two-sided slopes, while that of the one-sided slope is the weakest, which can indirectly explain the phenomena that the damage is most serious; (2) the amplifications of the peak accelerations gradually increase as the slope angles increase, and there are two inflection points which are the point where the slope angle is 45° and where the slope angle is 50°, respectively, which can explain the seismic phenomenon whereby landslide hazards mainly occur on the slopes whose slope angle is bigger than 45°. The amplification along the slope strike direction is basically consistent, and the step is smooth.

No MeSH data available.


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Shaking table test model of two-sided rock slope.
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ijerph-12-09181-f006: Shaking table test model of two-sided rock slope.

Mentions: One-sided rock slopes, two-sided rock slopes and four-sided rock slopes are adopted in this shaking table test to clarify the influence of the type of slope surface on acceleration. The test is briefly as follows: in the four-sided slope, the geometric dimension ratio is 1:160, the gravity ratio is 1:1, the time ratio is 1:3.16, the stress ratio is 1:3.16, the Poisson ratio is 1:1 and the internal frictional angle is 1:1. After the calculations based on a similar system, the height of four-sided rock slope is 0.8 m, the length of the bottom is 3.53 m and the width is 1.55 m, while the length of the top surface is 0.78 m and the width is 0.1 m; the four-sides have 30°, 45°, 50° and 60° slopes, respectively, as Figure 4 shows. In the one-sided model and the two-sided model, the geometric dimension ratio is 1:100, the gravity ratio is 1:1, the time ratio is 1:3.16, the stress ratio is 1:6.35, the Poisson ratio is 1:1 and the internal frictional angle is 1:1. After the calculations according to a similar system, the height of the one-sided slope is 1.807 m and the width is 3.5 m, the gradient varies in a range up to 50°, the river valley at the toe of slope is 0.173 m and the river bed inclines slightly, the gradient of the right hand slope is varied in the range from 30°–40°, the top is covered by a seriously weathered layer, as shown in Figure 5. The two-sided slope is 1.8 m high with a width of 3.5 m and includes steep terrain and gentle slope topography; the gradient of the steep terrain is varied in a range up to 50° and the gradient of the gentle slope is varied in the range up to 40°; on the basis of field investigation results, the soil layer and weathered layer on the surface of the slope are generalized to slope wash at the slope top, slope waist and slope foot, as shown in Figure 6. Descriptions of related shaking table tests of one-sided, two-sided and four-sided rock steep slopes can be found in [20,21,22], and are therefore they are not described in detail in this paper.


Analysis on Two Typical Landslide Hazard Phenomena in The Wenchuan Earthquake by Field Investigations and Shaking Table Tests.

Yang C, Zhang J, Liu F, Bi J, Jun Z - Int J Environ Res Public Health (2015)

Shaking table test model of two-sided rock slope.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555273&req=5

ijerph-12-09181-f006: Shaking table test model of two-sided rock slope.
Mentions: One-sided rock slopes, two-sided rock slopes and four-sided rock slopes are adopted in this shaking table test to clarify the influence of the type of slope surface on acceleration. The test is briefly as follows: in the four-sided slope, the geometric dimension ratio is 1:160, the gravity ratio is 1:1, the time ratio is 1:3.16, the stress ratio is 1:3.16, the Poisson ratio is 1:1 and the internal frictional angle is 1:1. After the calculations based on a similar system, the height of four-sided rock slope is 0.8 m, the length of the bottom is 3.53 m and the width is 1.55 m, while the length of the top surface is 0.78 m and the width is 0.1 m; the four-sides have 30°, 45°, 50° and 60° slopes, respectively, as Figure 4 shows. In the one-sided model and the two-sided model, the geometric dimension ratio is 1:100, the gravity ratio is 1:1, the time ratio is 1:3.16, the stress ratio is 1:6.35, the Poisson ratio is 1:1 and the internal frictional angle is 1:1. After the calculations according to a similar system, the height of the one-sided slope is 1.807 m and the width is 3.5 m, the gradient varies in a range up to 50°, the river valley at the toe of slope is 0.173 m and the river bed inclines slightly, the gradient of the right hand slope is varied in the range from 30°–40°, the top is covered by a seriously weathered layer, as shown in Figure 5. The two-sided slope is 1.8 m high with a width of 3.5 m and includes steep terrain and gentle slope topography; the gradient of the steep terrain is varied in a range up to 50° and the gradient of the gentle slope is varied in the range up to 40°; on the basis of field investigation results, the soil layer and weathered layer on the surface of the slope are generalized to slope wash at the slope top, slope waist and slope foot, as shown in Figure 6. Descriptions of related shaking table tests of one-sided, two-sided and four-sided rock steep slopes can be found in [20,21,22], and are therefore they are not described in detail in this paper.

Bottom Line: Considering the above disaster phenomena, the reasons are analyzed based on shaking table tests of one-sided, two-sided and four-sided slopes.The analysis results show that: (1) the amplifications of the peak accelerations of four-sided slopes is stronger than that of the two-sided slopes, while that of the one-sided slope is the weakest, which can indirectly explain the phenomena that the damage is most serious; (2) the amplifications of the peak accelerations gradually increase as the slope angles increase, and there are two inflection points which are the point where the slope angle is 45° and where the slope angle is 50°, respectively, which can explain the seismic phenomenon whereby landslide hazards mainly occur on the slopes whose slope angle is bigger than 45°.The amplification along the slope strike direction is basically consistent, and the step is smooth.

View Article: PubMed Central - PubMed

Affiliation: School of Civil Engineering, Key of Transportation Tnuuel Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China. yangchangwei56@163.com.

ABSTRACT
Based on our field investigations of landslide hazards in the Wenchuan earthquake, some findings can be reported: (1) the multi-aspect terrain facing empty isolated mountains and thin ridges reacted intensely to the earthquake and was seriously damaged; (2) the slope angles of most landslides was larger than 45°. Considering the above disaster phenomena, the reasons are analyzed based on shaking table tests of one-sided, two-sided and four-sided slopes. The analysis results show that: (1) the amplifications of the peak accelerations of four-sided slopes is stronger than that of the two-sided slopes, while that of the one-sided slope is the weakest, which can indirectly explain the phenomena that the damage is most serious; (2) the amplifications of the peak accelerations gradually increase as the slope angles increase, and there are two inflection points which are the point where the slope angle is 45° and where the slope angle is 50°, respectively, which can explain the seismic phenomenon whereby landslide hazards mainly occur on the slopes whose slope angle is bigger than 45°. The amplification along the slope strike direction is basically consistent, and the step is smooth.

No MeSH data available.


Related in: MedlinePlus