莱州湾南岸咸水入侵演化特征研究

发布时间：2018-01-01 02:24

本文关键词：莱州湾南岸咸水入侵演化特征研究　出处：《中国海洋大学》2014年硕士论文　论文类型：学位论文

【摘要】：咸水入侵是频发于海岸带地区，是在天然和人工双重作用下的缓变型地质灾害，会对当地工农业与居民的生活健康造成严重的负面影响。自晚更新世以来，随着冰期、间冰期气候变化以及海平面多次升降，渤海发生了沧州海侵、献县海侵和黄骅海侵以及它们之间的海退事件，莱州湾南岸滨海河流沉积和海相沉积平原区便相应地沉积了海、陆相间的地层。本次研究主要以莱州湾南岸为例，通过资料整编与分析、实地踏勘、样品分析、监测数据分析、建立地下水模型等方法探讨咸水入侵现象的演化特征，包括历史演化特征与发展特征。晚更新世以来在莱州湾南岸形成的地下卤水分布范围大，储量多，但地下卤水成因复杂，其也为咸水入侵提供物源基础。分析认为，地下卤水成矿条件受多种因素控制，莱州湾南岸的多源河流三角洲沉积演化模式为地下卤水资源的生成创造了良好的补给、运移、过滤、储存、封盖条件。在海退初期，p 湖水体由风暴潮作用下越过沙坝不断注入正常海水和位于其下部河流沉积物地下淡水共同组成，p 湖中产生的高矿化度盐水在回流渗滤作用下进入潮坪和三角洲前缘地带，p 湖水体将长时间保持较高浓度稳定状态，在返流过程中卤水盐度会发生水平带状分异；在海退成陆时期，长期蒸发作用和季节性河流物质运输形成卤水存储，陆相沉积物掩埋了前期卤水层即成为地下卤水层；如此大规模的三次海陆变迁，形成三个卤水层相间的分布特征。以p 湖—沙坝为卤水生成反应器，被溶解的组分在蒸发泵作用下产生分馏，在沉积物内发生离子交换作用，产生矿物蚀变，在回流渗滤作用下沿潮坪和三角洲前缘生成地下卤水。在综合分析地下卤水分布范围、顶底板埋深、含水层厚度、卤水浓度及卤水化学类型基础上，通过沉积背景和地下卤水分布对比研究，重新厘定自晚更新世以来莱州湾南岸地下卤水层与三次海侵之间关系，分析地下卤水分布特征及开采现状，为进一步研究地下卤水成因奠定沉积学基础，为合理有效利用海岸带地下卤水资源提供科学依据。同时，卤水的形成也为咸水入侵提供咸水物源基础。通过对莱州湾南岸的咸水入侵发展分析，影响咸水入侵的因素主要为地下水开采与研究区内的河流特征。其中咸淡水界面在监测时间范围运动分为三个阶段，整体上咸淡水界面向北移动1136.43m，平均年移动速度为1.2km/a，咸水入侵范围呈现减小的趋势，主要由于当地降雨与地下水开采共同作用导致。晚更新世地下水与降水补给、河流补给几乎没有关系，与地下水开采相关性较大，其咸水入侵与该地层卤水分布、咸水分布特征相关；全新世地下水在丰水期与降水、地下水开采相关，在平水期、枯水期与地下水开采相关，其补给源为周边地下水，咸水入侵现象与其周边地下水类型相关。潮汐作用对地下水的影响主要表现为滨海晚更新世地下水水位与矿化度动态变化呈现与潮汐波动相似的不规则正弦式曲线，全新世地下水波动规律并不明显，在距离海岸线150m处的晚更新世地下水水位与矿化度峰值较潮汐水位峰值滞后10min左右。通过地下水模型模拟，在不同开采强度的情况下，卤水区只受本区域的地下水开采影响，开采强度越大，，地下水矿化度降低的趋势越为明显，并不受其他区域地下水开采影响；在非卤水区开采，卤水区对其影响较小，矿化度较高区域受矿化度较低区域影响明显。咸淡水界面的运动受卤水开采影响较小，主要受地下水矿化度为1~50g/L区域地下水开采影响明显。
[Abstract]:The saltwater intrusion is frequent in coastal areas, is a slow change of geological disasters in the natural and artificial double function, will cause serious negative impact on the local industry and agriculture and the health of people. Since the late Pleistocene, with glacial interglacial, climate change and sea level rise and fall many times, the Cangzhou transgression between Bohai. Xianxian County Huanghua transgression and their transgression and regression, the South Bank of Laizhou Bay Coastal fluvial and marine sedimentary plain correspondingly sedimentary sea, between continental strata. This study mainly in the South Bank of Laizhou Bay as an example, through the compilation and analysis of data, field reconnaissance, sample analysis, monitoring data analysis, establish the model of groundwater methods to investigate the evolution characteristics of saltwater intrusion phenomenon, including the characteristics and development characteristics of the historical evolution.
Since the late Pleistocene formation in the South Bank of Laizhou Bay underground brine distribution range, reserves, but the underground brine causes complex, which also provide basis for the source of water intrusion. Analysis shows that the metallogenic conditions of underground brine is controlled by many factors, generating three deltas of multi-source River south of the Gulf of Laizhou for the evolution of underground brine resources create a good supply, transport, storage, filtration, sealing condition. In the early stage of regression, P Lake by the storm surges over the sand bar continuous injection of normal seawater and is arranged on the lower part of the river sediments were composed of underground water with high salinity, salt Lake ore P in the tidal flat and delta front zone in return filtration, P lake will maintain a high concentration and stable state for a long time, in the process of brine salinity reflux occurs in horizontal zonal differentiation; regression into land period, long period of evaporation And the seasonal river transport formation brine storage, continental sediments buried early brine layer is become underground brine layer; so three times large-scale sea changes, the distribution characteristics of the formation of three phases. In the P aquifer brine lake sand dam for the brine generation reactor, the dissolved components produced in evaporation fractionation pump function next, the ion exchange in the sediment, producing mineral alteration, generation of underground brine in reflux infiltration along the tidal flat and delta front. The comprehensive analysis of underground brine distribution, the top and bottom of the buried depth, thickness of aquifer, the concentration of brine and brine chemistry on the basis of the type, through the sedimentary background and distribution of underground brine comparative study on the relationship between the redefinition, since the late Pleistocene in Laizhou Bay and underground brine layer three transgression, analysis of underground brine distribution and exploitation status, for the further research of underground brine Water Genesis lays the foundation for sedimentology, and provides scientific basis for rational and effective utilization of underground brine resources in coastal zone. Meanwhile, brine formation also provides salt water source foundation for salt water intrusion.
Through the development of the South Bank of Laizhou Bay, salt water intrusion analysis, the influence factors of saltwater intrusion are mainly groundwater and rivers in the study area. The fresh salt water interface in the monitoring range of motion is divided into three stages on the whole, the interface of salt and fresh water northward movement of 1136.43m, the average mobile speed is 1.2km/a, the saltwater intrusion range show decreased, mainly due to the local rainfall and groundwater exploitation. The result of joint action of late Pleistocene groundwater and precipitation recharge, river supplies almost Never mind, and groundwater exploitation are greatly correlated with the invasion of the salt brine water distribution, water related distribution; Holocene groundwater in high water period and precipitation, groundwater exploitation, in the normal water period, low water period and groundwater exploitation, the supply source for the surrounding groundwater, salt water intrusion phenomenon and its surrounding groundwater types related as tidal. With the impact of groundwater is mainly manifested in the late Pleistocene coastal groundwater level and salinity showed dynamic changes and tidal fluctuations similar irregular sine curve, regularity of Holocene groundwater fluctuation is not obvious, the coastline of 150m distance in the late Pleistocene and the groundwater level and salinity peak tidal lag peak around 10min.
The groundwater simulation model, in different mining strength, brine area is only affected by the regional groundwater exploitation, mining strength increases, groundwater salinity decreased more obvious, is not affected by other factors of groundwater exploitation in mining area; non brine, brine area has little influence on the area, high degree of mineralization the low salinity region is obvious. The interface of salt and fresh water movement by the brine mining effect is mainly affected by the groundwater salinity 1~50g/L regional groundwater exploitation is obvious.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.2

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