黄河上游沙漠小流域粗沙岸坡重力侵蚀滑塌过程及型态的数值模拟

Numerical simulation on coarse sand bank collapse processes and shape response to gravitational erosion from a small desert watershed in the Upper Yellow River

采用黄河上游“十大孔兑”典型沙漠小流域“苏达尔沟”的数字高程数据,以黄土岸坡的滑塌过程和型态作为参照组,基于强度折减理论,通过数值模拟和野外实测资料对比验证,概化模拟降雨均匀入渗条件下沙漠粗沙岸坡的滑塌过程及型态.结果表明:受土体颗粒之间黏聚力的影响,粗沙岸坡主要表现为分层、片状滑塌,而黄土岸坡多表现为块状或团状滑塌;较之黄土岸坡的弧型滑动,粗沙岸坡为折线型滑动,滑塌型态直立,模拟与实测结果定性吻合.

Using the digital elevation data of“Sudalaer”,a typical desert watershed from ten tributaries area in the Upper Yellow River,and taking the processes and types of loess bank as the reference group,the process and types of desert coarse sand bank collapse under steady rainfall infiltration conditions in the Upper Yellow River were studied through Strength Reduction Theory based generalized numerical simulation as well as field observation analysis.The results indicate that under the influence of cohesive force,the coarse sand bank slope is mainly in the state of layering and flaky slumping,while the loess bank slope is mostly in the state of block or mass slumping.Compared with the arc sliding of loess bank slope,the coarse sand bank slope presents a broken line sliding,and the collapse pattern is upright,which is qualitatively consistent with the measured results.