土的最大干密度和最优含水率快速测定法

对快速击实试验研究成果进行了总结,并介绍了应用快速击实试验研究成果的经验.不论是重型击实还是轻型击实,也不论击实试验所给定的击实功能多大,应用"一点法"或"快速法"击实试验原理,对土料都有一定要求."一点法"击实试验与快速击实试验所用土体的比重在2.67～2.73之间,当被测土样的比重超越此范围时,在绘制击实曲线时可适当偏离ρdmax计算值的点,但这个误差是很小的,通常ρdmax的影响在±0.01 g/cm3以内,而对ωop的影响在±0.5%以内.结合工程实例,对击实试验成果的简化校正作了详细介绍.

Analysis on tailrace system with varying crown elevation at TGP's right bank underground power station

Taking TGP underground powerstation on right bank as an example,theoretical analysis and computation are conducted on transitional state of flow in tailrace system with varying crown elevation,and the analysis results demonstrate that the maximum dynamic water pressure on spiral case has no close relation with layout of tailrace system,but mainly depends on upstream flow accelerating time of power units,operating characteristics of hydraulic turbines and closing time and regulation of guide blades.From dynamic variation process of rotational speed in load rejection,it can be seen that the maximum step up of rotational speed takes place in the closing process of guide blades and the max. step up rate depends mainly on closing duration of guide blades and the amount of turbine discharge.For longer closing time and larger discharge,the step up of rotational speed is larger.Besides the flow inertia time of downstream tailrace flow passage,operation behaviour of turbine,closing regulation of guide blade,the vacuum degree at tailrace adit has also close relation with downstream water level.The vacuum degree at tailrace adit varies most significantly at the lowest downstream water level and improves gradually along with the rising of downstream water level.This analysis and computation can be referred for the design and computation of similar powerstation.