伊泰普围堰施工采用的安全标准

一、引言本文介绍了为确定伊泰普工程围堰堰顶高程所采用的水文安全标准。这种安全标准是根据围堰使用的时间,以及如果洪水超过选定的标准而发生漫顶流量时可能的毁坏和施工时间损失确定的。伊泰普水电站施工围堰,包括截断巴拉纳河进行导流用的围堰和为进行导流渠内的厂房施工的围堰。     

单轴及三轴压缩试验中测量横向应变的新方法

导言本文叙述了一种采用测量试样圆周应变的手段来测定圆柱试样的平均横向应变的方法。此方法是在试样周围绕一种金属丝,并用其电阻的改变来确定应变量。它的主要优点是测定的应变量为整个圆周的应变量,而不是某一点的应变量。它既可用于单轴压缩试验,也可用于不同侧压下的三轴压缩试     

地表水文学 第五部分 地表瞬时流

绪言本报告的最后部分论述地表水文学中一个较为疑难的方面,即流经地表过渡层的不稳定流的数字计算。我们在前面已经明确,这种过渡层具有一些土体到空气的渐变分层特性。有时过渡层如耕作层会有相当的厚度。在一些耕作良好的重粘土中,对厚20～40厘米的土层,水力传导率可以变化到六个量级。在平坦的细粒土层中,过渡层大为减     

俄罗斯极北地区的水电工程

俄罗斯极北地区的水电工程解决了许多在严寒条件和永冻土上进行施工的难题；表明水电站的修建是可行的，投入是很低的。这些水电站建成后都能在一定程度上满足北方地区的用电需求。     

SIMILARITY LAW OF FLUCTUATING PRESSURE WITHIN HYDRAULIC JUMP AREA

Through a series of model tests of five scales for 2-D free hydraulic jump, the da-ta of fluctuating pressure acting on the floor level within the hydraulic jump were obtained. Dur-ing the experiments, Froude number varied from 2.94 to 8.61, and Reynolds number rangedfrom 2×10~4 to 6×10~5. Experiment results indicate that the amplitude scale of fluctuating pres-sure is the length scale of model, i. e. P'=L, which agrees with gravity similarity law: Thefrequency scale of the fluctuating pressure is a unity i. e., f=1, which does not satisfy thegravity similarity law.     

THE FLOW PRODUCED IN PARTICLE-SUSPENSION BY AN INFINITE ROTATING DISK:SERIES SOLUTION

To the flow produced in particle-suspension by a rotating disk of infinite extent,the asymptotic behavior at infinity is analyzed.A corresponding series solution is presented.It isshown that this approach yields widely valid solutions of high accuracy for all the cases in whichthat suction or weak injection at the disk surface exists.For the cases that strong injection or par-ticle-free band exists,the series method fails.     

TURBULENCE MEASUREMENT INSTRUMENT WITH A SILICON PIEZORE-SISTANCE BEAM

A newly developed turbulence measurement instrument is introduced in the paper.The transducer of the device is based on the principle of the effect of silicon piezoresistance that isintegrated in a Wheatstone bridge on a pure silicon beam. At one end of the beam, a small lightball is installed as the target forced by the water flow. The other parts are prevented from thewater flow with a sophisticated stainless steel tube. The instrument can be used to measure turbu-lent velocities either in clear Water or in flows bearing hyperconcentration of sediment. It can al-so be used to measure velocities in both glass flume and model experiments as well as in pipe ex-periment by being mounted in a special way.     

提高动力问题直接积分法的精度

一、概述在结构动力分析中,广泛采用直接积分法求解时域内的运动方程。主要的方法分两类。第一类为显式方法。即将加速度和速度用连续的位移值表示,在运动方程中,加速度和速度被每一时间步长内所要求出的位移矢量所代替。这类方法的主要区别在于有各种不同的假定,它们的—个主要缺陷就是它们是条件稳定的。事实上可以说明所选时间步长增量必须远