为探究"三高一扰动"特殊环境下切顶卸压无煤柱自成巷顶板砂岩切缝的动态力学性能,利用自主设计的岩土体动态冲击力学试验系统,对粉砂岩进行不同热–水–力耦合条件下的冲击压缩试验,研究动态应力–应变特征、动变形模量与加...为探究"三高一扰动"特殊环境下切顶卸压无煤柱自成巷顶板砂岩切缝的动态力学性能,利用自主设计的岩土体动态冲击力学试验系统,对粉砂岩进行不同热–水–力耦合条件下的冲击压缩试验,研究动态应力–应变特征、动变形模量与加载率关系、以及加载率、轴压、围压、渗透水压、温度、吸收能与峰值应力和峰值应变的动态力学性能,利用扫描电镜(Scanning Electron Microscopy,SEM)研究粉砂岩试样断口面微观结构。研究结果表明:(1)在不同的动荷载作用下,粉砂岩试样的峰值应力和峰值应变均随轴压、围压、渗透水压、温度的升高而不断增大,脆性逐渐减弱而延性逐渐增强,变形破坏总体分为压密、弹性变形、塑性变形和破坏4个阶段;(2)动变形模量随着加载率的增大呈现出先增大后减小的发展趋势,动变形模量136GPa左右为一个临界阈值;(3)轴压、围压、水和温度对砂岩在热–水–力耦合特定环境下的动态冲击力学性能具有一定的增强效应;(4)随着峰值应变的增加,粉砂岩试样的吸收能呈线性增加趋势,其破碎变形与吸收能呈正相关。展开更多
The operating states of hydroelectric generating units vary widely as the operating condition change. The details of the operating characteristics and the operating region partitioning method are discussed for two typ...The operating states of hydroelectric generating units vary widely as the operating condition change. The details of the operating characteristics and the operating region partitioning method are discussed for two types of large Francis turbines in the Wanjiazhai Hydropower Plant and two same type large Kaplan turbines in the Shuikou Hydropower Plant. For the Wanjiazhai Hydropower units, the most critical factor affecting the operating stability is the hydraulic pressure fluctuations caused by the vortex rope in the draft tube. For Shuikou Hydropower units, the dynamic stresses as in the piston rod and the blade and the hydraulic thrust on the runner induced by the pressure fluctuations in the flow passage should be used to partition the operating regions. Analyzing the distribution cloud of operating characteristic factors which affects the operating stability in the hill-chart for each individual unit, the forbidden, stable and transient operating regions can be obtained.展开更多
文摘为探究"三高一扰动"特殊环境下切顶卸压无煤柱自成巷顶板砂岩切缝的动态力学性能,利用自主设计的岩土体动态冲击力学试验系统,对粉砂岩进行不同热–水–力耦合条件下的冲击压缩试验,研究动态应力–应变特征、动变形模量与加载率关系、以及加载率、轴压、围压、渗透水压、温度、吸收能与峰值应力和峰值应变的动态力学性能,利用扫描电镜(Scanning Electron Microscopy,SEM)研究粉砂岩试样断口面微观结构。研究结果表明:(1)在不同的动荷载作用下,粉砂岩试样的峰值应力和峰值应变均随轴压、围压、渗透水压、温度的升高而不断增大,脆性逐渐减弱而延性逐渐增强,变形破坏总体分为压密、弹性变形、塑性变形和破坏4个阶段;(2)动变形模量随着加载率的增大呈现出先增大后减小的发展趋势,动变形模量136GPa左右为一个临界阈值;(3)轴压、围压、水和温度对砂岩在热–水–力耦合特定环境下的动态冲击力学性能具有一定的增强效应;(4)随着峰值应变的增加,粉砂岩试样的吸收能呈线性增加趋势,其破碎变形与吸收能呈正相关。
基金supported by the National Natural Science Foundation of China (Grant Nos. 50879036 and 50979044) State Key Laboratory of Hydroscience and Engineering (Grant No. 2009T3)
文摘The operating states of hydroelectric generating units vary widely as the operating condition change. The details of the operating characteristics and the operating region partitioning method are discussed for two types of large Francis turbines in the Wanjiazhai Hydropower Plant and two same type large Kaplan turbines in the Shuikou Hydropower Plant. For the Wanjiazhai Hydropower units, the most critical factor affecting the operating stability is the hydraulic pressure fluctuations caused by the vortex rope in the draft tube. For Shuikou Hydropower units, the dynamic stresses as in the piston rod and the blade and the hydraulic thrust on the runner induced by the pressure fluctuations in the flow passage should be used to partition the operating regions. Analyzing the distribution cloud of operating characteristic factors which affects the operating stability in the hill-chart for each individual unit, the forbidden, stable and transient operating regions can be obtained.
