【摘要】 裂隙是岩溶含水系统的重要组成部分,裂隙水流运动对岩溶含水系统水流运动起到重要的控制作用。利用自行设计研制的具有不同转折角度、不同裂隙开度的复杂单裂隙物理模型,通过室内物理试验得到有、无裂隙条件下,水头差变化曲线,并基于能量方程推导得出水流流经裂隙时产生的总水头损失计算式,计算得到不同裂隙开度(1～2.6 mm)、不同流速(0～40 cm/s)条件下,裂隙总水头损失对不同转折角度(0°～165°)的变化曲线,利用修正立方定律和达西-魏斯巴赫公式计算裂隙平行部分的沿程水头损失,总水头损失与之相减得到转折角处的局部水头损失。结果表明:随裂隙开度增大,流速增大,裂隙总水头损失、转折处局部水头损失均呈增大趋势,且流速越大,趋势越明显;对水头损失与平均流速之间的关系曲线进行拟合分析,发现裂隙总水头损失、转折处局部水头损失与平均流速之间均呈二次函数关系,可用Forchheimer方程描述,且总水头损失、局部水头损失与平均流速之间函数关系的二次项系数随裂隙开度增大基本呈增大趋势,最终得到二次项系数分布的上包线与下包线,而一次项系数分布比较集中,总水头损失的一次项系数分布于-0.1～0.5之间,转折处局部水头损失的一次项系数分布于-0.1～0.25之间。更多还原

【Abstract】 Fractures are the main part of karst systems.Fracture flow has a significant influence on the flow in the karst systems.The mechanism of fracture flow needs further researches.Based on the physical models of complex-single fractures with different turning angels and apertures,laboratory experiments are conducted to investigate the relationship between fractures hydraulic head loss and turning angels(varying from 0° to 165°)under different velocities(varying from 0 to 40 cm/s) and different apertures(1 to 2.5 mm).The curves of hydraulic head differences under the conditions with fractures and without fractures are obtained.Based on energy equations,the total hydraulic head losses calculation formula is obtained.Based on the verified Cubic Law and Darcy-Weisbach equation,the local hydraulic head losses are calculated,and the local hydraulichead losses are also obtained.The results show that both the total hydraulic head losses and the local hydraulic head losses increase with the increasing aperture and velocity.Using curve fitting,the relationship between the total hydraulic head loss and velocity is quadratic function and the relationship between the local hydraulic head loss and velocity is found to be expressed as a quadratic function,which can be depicted as the Forchheimer function.The quadratic term coefficients increase with the fracture aperture.In addition,the distributions of the quadratic term coefficients and the first term coefficients are obtained.The quadratic term coefficients occur between the upper envelope curve and the lower envelope curve.The first term coefficients of the total hydraulic head loss varies from-0.1 to 0.5,while the first term coefficients of the local hydraulic head loss varies from-0.1 to 0.25.更多还原