泥石流堆积物粒度分形特征及影响因素分析
|
摘要
汶川地震诱发了大量的泥石流,给山区带来了巨大的人员伤亡及财产损失,为了更好地对泥石流特征进行研究并对其危险性进行预测,通过野外取样对泥石流堆积物进行了粒度分析,并对汶川地震灾区泥石流堆积物的分形结构特征以及泥石流物源区岩性、松散物质量及沟道坡降对泥石流堆积物颗粒组成的影响进行了分析。结果表明,其粒度分维值介于2～3之间,平均值为2.49,标准差为0.19,分维值的离散度比较低。粉砂岩的分维值最小,其次是砂岩和泥灰岩;石英闪长岩的分维值最大,其次为石灰岩。分维值的变化趋势与松散物质量的变化趋势极为相似,分维值随着松散物质量的增大而增大。泥石流堆积物的分维还受到沟道坡降的影响,在其它影响因素相同的情况下,分维值随着沟道坡降的增大而增大。地震后泥石流堆积物的分形特征体现了泥石流危险度的大小,可为泥石流活动特征及危险性预测提供依据。
Numerous debris flows were triggered by the Wenchuan earthquake,bringing a large number of casualties and property loss to the mountain area.For better understanding and prediction of debris flow,particle size analyses were carried out on field samples of debris flow deposits.Fractal structures of debris flow deposits were also analyzed based on fractal theory in the area.The fractal dimension ranged from 2 to 3,with an average of 2.49 and standard deviation of 0.19,showing a low dispersion degree of fractal dimension.The influences of lithology,total volume of loose materials,and slopes on the particle composition of debris flow deposits were studied.The results show that the deposits of siltstone have the minimum fractal dimension value,followed by those of sandstone and marl.In contrast,the deposits of quartz diorite and limestone have the highest and the second highest fractal dimension value.The fractal dimension values of the deposits increases with the total volume of loose materials,as well as the gully slope.The fractal characteristics of the deposit indicate the risk of debris flow,providing evidences for characterization and prediction of debris flow activities.
Numerous debris flows were triggered by the Wenchuan earthquake,bringing a large number of casualties and property loss to the mountain area.For better understanding and prediction of debris flow,particle size analyses were carried out on field samples of debris flow deposits.Fractal structures of debris flow deposits were also analyzed based on fractal theory in the area.The fractal dimension ranged from 2 to 3,with an average of 2.49 and standard deviation of 0.19,showing a low dispersion degree of fractal dimension.The influences of lithology,total volume of loose materials,and slopes on the particle composition of debris flow deposits were studied.The results show that the deposits of siltstone have the minimum fractal dimension value,followed by those of sandstone and marl.In contrast,the deposits of quartz diorite and limestone have the highest and the second highest fractal dimension value.The fractal dimension values of the deposits increases with the total volume of loose materials,as well as the gully slope.The fractal characteristics of the deposit indicate the risk of debris flow,providing evidences for characterization and prediction of debris flow activities.
引文
[1]崔鹏,庄建琦,陈兴长,等.汶川地震区震后泥石流活动特征与防治对策[J].四川大学学报:工程科学版,2010,42(5):10-19.
[2]易顺民,孙云志.泥石流的分形特征及其意义[J].地理科学,1997,17(1):24-31.
[3]Cui Peng,Chen Xiaoqing,Zhu Yingyan,et al.The Wen-chuan Earthquake(May 12,2008),Sichuan Province,China,and resulting geohazards[J].Nat.Hazards,2011,56(1):19-36.
[4]崔鹏,韦方强,何思明,等.“5.12”汶川地震诱发的山地灾害及减灾措施[J].山地学报,2008,26(3):280-282.
[5]庄建琦,崔鹏,胡凯衡,等.沟道松散物质起动形成泥石流实验研究[J].四川大学学报:工程科学版,2010,42(5):230-236.
[6]任凯珍.泥石流堆积形态与坡降的相关性分析[J].分析研究,2010,5(2):24-27.
[2]易顺民,孙云志.泥石流的分形特征及其意义[J].地理科学,1997,17(1):24-31.
[3]Cui Peng,Chen Xiaoqing,Zhu Yingyan,et al.The Wen-chuan Earthquake(May 12,2008),Sichuan Province,China,and resulting geohazards[J].Nat.Hazards,2011,56(1):19-36.
[4]崔鹏,韦方强,何思明,等.“5.12”汶川地震诱发的山地灾害及减灾措施[J].山地学报,2008,26(3):280-282.
[5]庄建琦,崔鹏,胡凯衡,等.沟道松散物质起动形成泥石流实验研究[J].四川大学学报:工程科学版,2010,42(5):230-236.
[6]任凯珍.泥石流堆积形态与坡降的相关性分析[J].分析研究,2010,5(2):24-27.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心