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| 岩石裂隙中水沙渗透滞后性的试验研究 |
| Test study on hysteresis of water-sand flow in rock fracture |
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| DOI： |
| 中文关键词: 滞回性 岩石裂隙 水沙混合液 渗透速度 渗流速度 |
| 英文关键词: hysteresis rock fracture water-sand mixture permeate velocity seepage velocity |
| 基金项目:国家自然科学基金资助项目（11502229，51404266，51574228）；湖南省教育厅资助科研项目（14C0427） |
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| 中文摘要: |
| 利用一种岩石裂隙水沙渗透试验系统开展了水沙在平面平行裂隙中流动的滞后性的试验研究，分析了渗流速度-压力梯度闭环曲线的特征，解释了滞后现象的原因.试验结果表明：当渗流速度由零增大到1.77 mm/s再减小到零时，渗流速度-压力梯度曲线自行封闭，形成滞环；由于裂隙开度、粗糙度、沙粒径和沙浓度的不同，滞回曲线呈现凸镜形、月牙形、“8”字形、勺形和裂缝形等多种形状；水沙混合液与岩石裂隙面的接触角变化引起回程中渗透速度沿裂隙宽度方向分布变化，这是岩石裂隙中水沙渗透存在滞后现象的主要原因；沙粒在岩石裂隙面的沉积、水沙在岩石裂隙中运动形态的转变、水沙混合液的粘塑性是岩石裂隙中水沙渗透存在滞后现象的重要原因. |
| 英文摘要: |
| A test system of water-sand permeability in fractured rock was used to explore the hysteresis of water-sand flow between two parallel fracture plains, the characteristics about the closed seepage velocity-pressure gradient curve were analyzed, and the reasons of hysteresis were discussed. The results show that, 1) when seepage velocity increase from 0 to 1.77 mm/s then decrease to zero, the velocity-pressure gradient curve forms closed-loop; 2) because of the difference in opening and roughness of fracture, and difference in concentration and particle size of sand, the hysteresis curves take on several shapes, include convex shaped loop, crescent shaped loop, dipper shaped loop, “8” shaped loop, and Crack shaped loop; 3) the main reasons for hysteresis is that the distribution in the flow velocity of water-sand through the fracture on the back trip is different from that on the forward trip owing to change of the contact angle among water, sand and rock fracture surfaces; 4) the important reasons for hysteresis include the deposit of sand grain on the fracture, the changes within the flow regime of water-sand in the fracture, and the viscoplasticity of water-sand mixture, etc. |
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