波浪作用下砂质滩坝的沉积过程与沉积模式——基于水槽沉积模拟实验研究  

Process and Model of Sedimentation of Sandy Beach Bar Due to Wave Action:An experimental study based on sink sedimentation simulation

作　　者：尹力 冯文杰[1] 尹艳树[1] 雷诚 徐庆岩[2] 何一鸣 YIN Li;FENG WenJie;YIN YanShu;LEI Cheng;XU QingYan;HE YiMing(School of Geosciences,Yangtze University,Wuhan 430100,China;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China)

机构地区：[1]长江大学地球科学学院,武汉430100 [2]中国石油勘探开发研究院,北京100083

出　　处：《沉积学报》2022年第5期1393-1405,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金(41872138)。

摘　　要：受波浪及沿岸流影响,在滨岸地区形成的滩坝砂体是滨海(湖)带发育的主要砂体类型。目前国内外学者对滩坝沉积砂体的认识多来自于现代沉积和油气地质特征,对滩坝砂体的沉积机制和内部结构研究相对较弱。基于沉积水槽实验,采用规则波浪对沙质斜坡滨岸带进行模拟实验,观测波浪作用下滨岸带滩坝形成过程和波浪运动特征,记录波浪作用下滨岸带沙质滩坝在不同浪带平面时空演化规律。实验结果显示:波浪是改造湖岸原有沉积物的关键驱动力,波浪作用下沙质岸滩床面泥砂将发生输移运动,而滩坝是陆湖(海)泥沙在水动力驱动下搬运沉积的结果,水动力的强弱及水流结构引起泥沙在空间上的不均匀输运和分布,进而塑造不同的滩坝形态。与强波浪相关的高水位可以加速滩坝系统的形成并最终形成大规模的滩坝砂;相比之下,与较弱波浪相关的低水位只能略微改变初始沉积物形态。根据不同的沉积物特征可将实验中的滩坝系统分为三类:冲浪带和碎浪带滩坝系统近端部分的大规模厚层坝砂,破浪带和升浪带滩坝系统中部分布广泛的薄滩砂,以及位于滩坝系统中远端的弧形或平行排列的脊状、砂纹坝砂。建立了水槽实验模式下滩坝沉积模式,可用于指导油气勘探开发。Beach sand bodies that are formed in coastal regions by waves and coastal currents are the major sand type in coastal(or lake)beaches.Present understanding of sand bodies deposited on beaches mainly comes from observation of modern deposition and petroleum geological features,but there are relatively few studies of the sedimentation mechanism itself and the internal structure of beach sand bodies.In this study,a beach bar sedimentation model was constructed to guide oil and gas exploration and development.A sandy slope coastal zone formed by regular waves was simulated in a sink-sedimentation experiment in which the formation of a coastal beach bar due to wave action,and the wave motion was observed.Experimental results show that waves are the main force transporting the original sediments in lakeshore and on coastal beach bars.Beach bars are the result of migration and sedimentation of lakeshore and coastal sediments.Differences in the intensity of hydrodynamic forces and flow structures cause the spatial migration and distribution of sediments to differ,thus creating various forms of beach bar.Deep water and strong wave action accelerate the formation of beach bar systems and eventually form large-scale sand bodies on a beach.Conversely,shallow water and weak wave action merely change the forms of the initial sediments.The beach bar systems in the experiment were divided into three types:large-scale,thick sand bodies near a beach bar systems in the surf and breaker zone;partial extensively distributed thin beach sandbars in the breaker zone and rising zone;and ridges and sand-texture sandbars in parallel arcs at the middle and far ends of the beach.

关 键 词：水槽实验 滩坝 沉积过程 沉积构型 

分 类 号：P512.2[天文地球—地质学]