北方岩溶水系统优势径流通道特征研究

Because the dominant seepage path of karst is controlled by the heterogeneity of medium,people hardly understand its characteristics.The traditional research methods,such as Spring flow attenuation analysis,Indoor physical model simulation,numerical simulation inversion,can’t finely depict and playback complex hydrodynamic process of the karst-water system.The topic adoptes many-ways to studying on dominant flowing path-fissure-fine pore fissure void characteristics and hydraulic properties、hydro-chemical variation law,Water temperature variation law of dominant flowing path-fissure-fine pore fissure water release,such as recharge test,hydrochemical tracing,temperature tracer,feld real-time monitoring,hole imaging,hole velocity measurement,SEM,seepage analysis of full diameter core,stratified sampling,flow field analysis,hydrology geochemical inversion,numerical simulation,and so on.Deeply analyze on the relationship of dominant flowing path’ formation,pore throat characteristic,sedimentary characteristics,heterogeneous characteristics.Explore the influence of different pore types on the dominant seepage path and reveal quantitative relationship between porosity and permeability of different types of voids.Based on temperature tracer,pore structure and hydraulic properties,formation permeability,permeability level difference in the inner layer,pore throat radius, using the numerical simulation and stochastic model to describe dominant seepage path,and check by field measured data of karst spring region in Jinan.The results are expected to enrich the research contents of karst hydrogeology.

受介质非均质性制约，人们对岩溶优势渗流通道特征知之甚少，传统的泉流量衰减分析、室内物理模型模拟、数值模拟反演等研究方法，均不能精细刻画与再现岩溶水系统复杂的水动力过程。本课题采用回灌试验、水化学示踪、温度示踪、野外实时监测、孔内成像、孔内测速、电镜扫描、全直径岩芯孔渗分析、分层采样、流场分析、水文地球化学反演与数值模拟等方法，研究优势渗流通道-裂隙-小孔隙裂隙的空隙特征，研究优势渗流通道-裂隙-小孔隙裂隙释水的水力性质、水化学指标变化规律、水温变化规律。深入分析优势渗流通道的形成与孔喉特征、沉积特征、非均质特征等要素的关系；探讨不同空隙类型对优势渗流通道的影响，揭示不同类型空隙的孔隙性与渗透性定量关系。基于温度示踪、空隙结构与水力性质、地层渗透率及层内渗透率级差、孔喉半径等要素采用数值模拟与随机模型识别优势渗流通道，通过济南泉域野外实测数据进行校验。本成果可望丰富岩溶水文地质学研究内容。

岩溶介质非均质性导致岩溶水运动复杂，精细刻画岩溶水动力过程是水文地质领域亟待突破的难点问题之一。项目以济南泉域为例，从岩溶含水介质的空隙结构特征入手，采用野外试验、室内实验等工作手段，结合分形理论、频率分析、时间序列分析、三维图像数字建模等新技术，研究岩溶水系统优势径流通道特征。取得主要成果如下：.1）岩溶大泉排泄区介质结构特征研究表明，岩溶含水介质孔隙结构类型及渗透性差异性巨大；分形维数与孔隙度是正相关；岩溶径流通道为单一管道型与多管道型并存；且毛管束越简单其渗透率越高。不同尺度空隙类型的水力特征研究表明，奥陶纪灰岩岩溶最发育、连通性好，其次是寒武纪张夏灰岩、凤山组灰岩；泉域排泄区岩溶连通性优于补给径流区，排泄区地下水平均流速320.8m/d，远大于补给径流区。.2）研究岩溶发育带、裂隙带水温发现，岩溶区垂向上有四种类型温深曲线；形成了判别水平径流通道的温深曲线拐点法；建立了热传导模型计算表明岩溶水垂向交替速率远远低于示踪试验确定的水平视流速。.3）制定岩溶区优势渗流通道特征因子判别标准，形成了识别优势渗流通道的模糊评判法。将管道流与渗流耦合提高岩溶大泉水位预测精度。基于优势渗流通道识别，创立了SCE-UA耦合优化算法的模拟-优化反演模型，研发岩溶水污染溯源技术方法。.4）基于时间序列分析，解析了大裂隙-管道流和裂隙-孔隙流对泉水动态影响，形成了北方岩溶大泉动态对降水时滞响应的判别方法。构建了动态频率分析法和水化学法相结合的泉水补给来源混合比定量计算方法，首次确定趵突泉、黑虎泉、珍珠泉与五龙潭补给来源的混合比。.主要创新：揭示岩溶介质不同空隙类型孔隙性与渗透性的定量关系，建立北方岩溶水系统优势径流通道识别方法。研究成果不仅丰富和深化了对岩溶水运动特征的认识，也对北方岩溶大泉保护有指导意义。