刘怀湘, 王兆印, 陆永军, 余国安. 山区下切河流地貌演变机理及其与河床结构的关系[J]. 水科学进展, 2011, 22(3): 367-372.
引用本文: 刘怀湘, 王兆印, 陆永军, 余国安. 山区下切河流地貌演变机理及其与河床结构的关系[J]. 水科学进展, 2011, 22(3): 367-372.
LIU Huai-xiang, WANG Zhao-yin, LU Yong-jun, YU Guo-an. Mechanism of morphological evolution in incised river and its relationship to streambed structures[J]. Advances in Water Science, 2011, 22(3): 367-372.
Citation: LIU Huai-xiang, WANG Zhao-yin, LU Yong-jun, YU Guo-an. Mechanism of morphological evolution in incised river and its relationship to streambed structures[J]. Advances in Water Science, 2011, 22(3): 367-372.

山区下切河流地貌演变机理及其与河床结构的关系

Mechanism of morphological evolution in incised river and its relationship to streambed structures

  • 摘要: 为研究河床结构在下切性河流地貌演变过程中所起到的作用与影响机制,对中国典型下切性河流区域的地貌特征与河床结构发育进行了调查与统计分析。结果表明,当河流剧烈下切使得河谷边坡超过临界坡度后,易于失稳而发生大规模的崩塌滑坡现象,河流演变从而进入下切拓宽阶段。大量边坡物质进入河道,促进了河床结构的发育,能够维持较高的河道纵坡降,形成裂点。河床结构是河流系统自我调节作用的体现,形成了"侵蚀下切-崩塌滑坡-河床结构发育-抑制侵蚀下切-平衡"这一负反馈机制。在这一机制的作用下,如果外在条件(如地壳抬升)不变,河流系统的演变方向将趋于平衡。

     

    Abstract: Streambed structures are developed in many mountain incised rivers as a result of fluvial morphology.They affect the further morphological process in some aspects such as channel stability enhancement.In order to study the role of the structures in morphological evolution in incised river channels,the landform features and structures were investigated and analyzed in the typical incised rivers.The results show that landslides and avalanches would likely occur due to earthquakes or rainstorms when the valleys are deeply incised and the valley slopes exceed a critical value.Thus,the river evolution will enter to a new phase of fluvial geomorphology after incision widening.A large amount of substances enters into channels enhance the intensity of streambed structures,and sustain higher gradients and form river knickpoints.This reflects the river system's selfadjustment,and in turn,reveals the existence of a negative feedback mechanism that is "incisionlandslides structures developmentincision impededequilibrium".The mechanism can lead the incised river system into the state of equilibrium,in case of invariable input conditions.

     

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