The Investigation of Landslide Pattern on Bamboo Forests

Autor: Yao-Jung Chen, 陳燿榮
Rok vydání: 2006
Druh dokumentu: 學位論文 ; thesis
Popis: 94
On July 2 and August 25 in 2004, the central part of Taiwan was invaded by Typhoon MINGDOLEE and AERE. Due to the very heavy rainfall occurred in typhoon, it caused a serious landslide and debris flow in the central mountain area. Among them, some parts of landslide were found on the bamboo forest lands, therefore, it led to the public suspicions on bamboo''s capability in soil and water conservation. In this study, a total of 12 plot survey stations were set up on the bamboo landslide area around Tai-An town in Miao­Li County,Ho-Ping town, and Dong-Shi town in Taichung County. The maximum rainfall intensity observed during the typhoon attacking in this surrounding area was 108.5 mm/hr in neighboring Xiang-bi station, 125 mm/hr in Shuang-chi station, and 124.5 mm/hr in Dong-shi station. The elevation of bamboo forest investigated was in range of 501~758 m, with the slope between 29~50°. The soil was loam soil. Ten surveys were carried out in each plot from November 2004 to December 2005 to investigate the continuous pattern after landslide. Regression analysis showed a high positive correlation with the determination coefficient 0.919 between avalanche, rainfall intensity and slope. A continuous collapse occurred if the rainfall intensity was greater than 31.5 mm/hr. Among the sample sizes of total 120 observations in all plots, only 10 continuous collapse with 219.5 m2 in avalanche, approximately 0.67％ of 3.28 ha in the initial landslide acreage. The rhizome survey showed that, because of the widespread of rhizome underground, bamboo forest forms a strong web underground, just like the steel bar web in the building. thus, it provides a good way for the soil protection. On rhizome strength test run using 100 T test machine showed the average of tensile strength was 176.5 kgf/cm2 for living rhizome, 264.8 kgf/cm2 for dead rhizome, shearing stress was 92.8 kgf/cm2 in average, approximately 10％ of steel bar strength. Even for dead rhizome, the tensile strength is still high, therefore, to be considered to be valid for soil protection purpose.
Databáze: Networked Digital Library of Theses & Dissertations
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