采砂对天然河床断面演变及堤防稳定影响分析

Influence Analysis of Sand Mining on Riverbed Section Evolution and Embankment Safety

近些年,建筑行业对河砂的需求量急增,导致部分河道采砂量远大于其河流天然泥砂淤积量,河床主断面下切,河道深泓向堤岸移动。过量、无序的采砂已成为影响河道防洪安全及堤防边坡稳定的重要影响因素。以天然河段为研究对象,简单用水流模型模拟了采砂坑附近水位、流场变化影响。根据水下实测资料,分析人工采砂对河床纵、横断面形态及堤防边坡抗滑稳定性的影响。结果表明:人工采砂促使河道河床局部下切,最大下切深度达17 m,对河道纵横断面演变产生重要影响。近岸采砂改变了原有河床边界条件,降低了泥沙水下稳定休止角,堤防边坡抗滑稳定性系数急剧下降,严重威胁堤防安全稳定,控制采砂、保护堤岸安全是非常迫切的。

In recent years, the demand for river sand in the construction industry has increased rapidly, which has resulted in the sand excavation in some rivers much larger than that in the river. The main section of the river bed is cut down and the river channel moves toward the bank. Excessive and disorderly sand mining has become an important factor influencing river flood safety and slope stability. In this paper, the effects of water level and flow field near the mining pits are simulated by the flow model, according to the underwater measured data, analysis of artificial sand mining vertical and horizontal cross - sectional analysis and dike slope stability against slid- ing. The results show that artificial sand excavation can promote the channel cutting and the maximum undercutting depth is 17 m, which has important influence on the longitudinal and transverse section evolution. The near shore sand mining changed the boundary conditions of the original river bed, reduced the stability angle of the sand underwater stability, and the slope stability coefficient of the embankment slope declined sharply, which threatened the safety and stability of the embankment seriously, Control sand mining and protection of the embankment safety is very urgent.