应强, 何杰, 辛文杰. 巨型人工采砂坑对伶仃洋自然演变的影响[J]. 水科学进展, 2019, 30(6): 915-922. DOI: 10.14042/j.cnki.32.1309.2019.06.016
引用本文: 应强, 何杰, 辛文杰. 巨型人工采砂坑对伶仃洋自然演变的影响[J]. 水科学进展, 2019, 30(6): 915-922. DOI: 10.14042/j.cnki.32.1309.2019.06.016
YING Qiang, HE Jie, XIN Wenjie. Influence of giant artificial sand pits on the natural evolution of Lingding Bay[J]. Advances in Water Science, 2019, 30(6): 915-922. DOI: 10.14042/j.cnki.32.1309.2019.06.016
Citation: YING Qiang, HE Jie, XIN Wenjie. Influence of giant artificial sand pits on the natural evolution of Lingding Bay[J]. Advances in Water Science, 2019, 30(6): 915-922. DOI: 10.14042/j.cnki.32.1309.2019.06.016

巨型人工采砂坑对伶仃洋自然演变的影响

Influence of giant artificial sand pits on the natural evolution of Lingding Bay

  • 摘要: 伶仃洋内建有华南最大的两个主枢纽港及相连的深水航道,长期保持"三滩两槽"稳定格局是广州港选择西槽开发深水航道并取得成功的关键基础。2008年以后,由于在中滩上人工采砂,现已形成了容积达7×108m3的巨型采砂坑,直接影响了伶仃洋的滩槽演变。采用现场调查和数值模拟等方法,分析了采砂活动过程中对周围水体及地形的影响,指出采砂区域水体含沙量为1.5~2.8kg/m3,最大可达5kg/m3以上,远大于采砂前0.2kg/m3,可引起附近海床淤积,对港珠澳大桥桥区的海床稳定也会产生影响。同时,采砂坑形成后潮位、潮流、潮量出现较大改变的区域主要在采砂坑及其附近水域,表现为潮位下降(小于1cm),潮流减小,采砂坑内以泥沙回淤为主(33cm/a),坑周围海床呈侵蚀冲刷状态,南侧冲刷较大。此外,现状条件下采砂坑以回淤为主,回淤时间预计20年,但在2#、3#采砂坑或2#、4#采砂坑连通等不利状况下,有可能形成新的潮流通道,改变现有"三滩二槽"的格局,对目前已有航道维护和港口生产造成不利影响。

     

    Abstract: Lingding Bay has two main hub ports and connected deepwater waterways in South China. Maintaining the stable pattern of "three beaches and two troughs" is the key basis for the Western trough deepwater waterways development in Guangzhou Port. Since 2008,due to artificial sand digging on the middle beach,three huge sand pits with total volume of 7×108 m3 has been formed,which directly affects the evolution of the beach and trough in Lingding Bay. By means of field investigation and numerical simulation,the influence of sand mining on surrounding water body and topography is analyzed. It is pointed out that the sediment concentration in the sediment digging area can increase greatly from 0.2 kg/m3 to 1.5-2.8 kg/m3 (up to 5kg/m3). This will increase the deposition of the nearby seabed and also affect the waters of the Hong Kong-Zhuhai-Macao Bridge. The influence of hydrological factors on the formation of sand pits are calculated. The results show that the main changes of tide level,tidal current and tidal volume are in the sand pit and its adjacent waters. The main changes are the tidal level decreases (less than 1 cm),the tidal current decreases,and sediment deposition is mainly in the sand pit (33 cm/a). The seabed around the pit is scoured,and the scour in the south side is larger. At present,sand pits are mainly silted up,and the time of silting back is expected to take 20 years. When 2#,3# sand pits or 2#,4# sand pits are connected,it is possible to form a new tidal current channel,change the existing pattern of "three beaches and two troughs",and have a negative impact on the existing channel maintenance and port production.

     

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