NHRI-4000型高性能大接触面直剪仪的研制

介绍了NHRI-4000型高性能大接触面直剪仪研制与运用情况。采用数字PID模糊控制方式,实现垂直荷载和水平荷载的控制精度;采用MCS51单片机控制单元和多机通信等方式,实现垂直荷载和水平荷载的控制;在硬件电路上采用低通滤波等办法,在软件方面采用定量预测方法平滑测试信号,实现了传感器测量稳定性要求;引入Spcomm控件和定时控件,运用Delphi语言进行编程,实现了自动控制、自动采集、实时绘图等功能。

Key issues on seepage flow analysis in large scale hydropower projects

The researches indicate that the Biot theory has model defects in describing the mechanical characteristics of saturated soil, and that it is more reasonable to describe the mechanical behaviors of saturated soil by using the theory of porous medium. Based on the theory of porous medium, the torsional vibration of the saturated soil is solved by the Novak plane strain hypothesis, and also obtained is the ring displacement of saturated soil. The torsional dynamic impedance is obtained by the stress-displacement relationship of the soil skeleton, the torsional vibration of single pile in saturated soil is investigated based on the torsional dynamic impedance, and the influence of parameters on the properties of the torsional complex stiffness is also discussed. The results show that the curves of torsional complex stiffness varying with frequency have peaks, the system of pile-soil has resonance, and the length-diameter ratio and modulus ratio have great effect on the torsional complex stiffness, while the influence of coupling coefficient is little, but it cannot be negelected.