府谷县皇甫川防洪工程地质探析

Expolration and Analysis on Flood Control Engineering of Huangfuchuan in Fugu County

采用工程地质测绘、钻探、坑探及野外与室内试验相结合的综合勘察方法,对府谷县皇甫川防洪工程地质进行勘察,并对堤基土的渗透稳定和抗冲能力等问题进行评价。结果表明,工程区属构造相对稳定区,相应的地震基本烈度Ⅵ度;工程区地下水类型主要为第四系松散层孔隙潜水及基岩裂隙水,河谷两岸地下水位高于河水,对钢结构具弱腐蚀性;堤基以细砂及砂砾石、砾石层为主,抗冲刷能力较差,建议平直段冲刷深度可按1.6 m～2.0 m考虑,在强侧蚀段及迎流顶冲段冲刷深度可按2.3 m～2.5 m考虑;沿线堤基不存在液化问题,但存在渗透稳定问题,细砂及砾石易产生流土及管涌,且抗冲刷能力较差,洪水期河水易对堤脚形成冲刷破坏,建议迎水坡堤脚采取抗冲刷措施。

The comprehensive survey method combining engineering geological mapping, drilling, pit exploration and field and indoor test was used to investigate the flood control engineering geology of Huangfuchuan in Fugu County, and the problems of seepage stability and impact resistance of the embankment soil were evaluated. The results show that the engineering area is a relatively stable area, and the corresponding basic seismic intensity is VI. The groundwater type in the engineering area is mainly Quaternary loose layer pore diving and bedrock fissure water. The groundwater level on both sides of the river valley is higher than that of river water, which is weakly corrosiveto the steel structure. The foundation of the embankment is mainly composed of fine sand, gravel and gravel, and the anti-scouring ability is poor. It is recommended that the flushing depth of the straight section can be considered from 1.6 m to 2.0 m, in the strong lateral erosion section and the upstream erosion section. The scouring depth can be considered from 2.3 m to 2.5 m;there is no liquefaction problem along the levee foundation, but there is a problem of osmotic stability. Fine sand and gravel are prone to flow and piping, and the erosion resistance is poor. Forming erosion damage,it is recommended to take anti-scour measures on the foot of the slope.