南三河沉管工程基槽开挖对海域水环境的影响

Influence of Trench Excavation of the Nansan River Immersed Tube on Water Environment

南三河沉管是鉴江供水枢纽工程中的一处跨海管道工程,管道基槽开挖会对周围海域水质产生影响。基于建立的二维非稳态水环境数学模型,利用同步水文水质监测数据对模型参数进行率定,并反演得到SS源强浓度,继而预测施工期SS对海域水环境的影响范围及程度。结果表明:距基槽中心50 m范围的SS源强浓度达到70 mg/L;SS会对基槽中心线上下游各700 m范围内的水域产生影响(增量≥10 mg/L),影响程度以挖槽为中心线向两侧递减。

Nansan River immersed tube is a cross-sea pipeline project, a part of Jianjiang Water Supply Project. Trench excavation will influence water quality. In this paper, a water environment mathematical model was established. The parameters of the model were calibrated by using synchronous hydrological and water quality monitoring data. The source strength of SS concentration was obtained by the inversion method. Based on these, the water environmental impacts of SS during construction period were predicted. The results show that： SS concentration range up to 70 mg/L about 50 meters from the trench center; The closer to trench, the greater degree of the influence.