球应力振动仪的研制与试用

鉴于复杂振动荷载下地基和土工建筑物动态反应的研究存在一定的困难，因此将 复杂振动荷载分解为球应力振动与偏应力振动进行研究。为了探讨球应力振动下土的 动力特性，研制了球应力振动仪。该仪器可以测出作用在试样上振动球应力的大小， 同时可以测出不排水试样在不同振动球应力作用下孔隙水压力的变化过程。将其结果 与动三轴试验相应的试验结果进行比较，可以获得振动球应力对饱和砂上液化影响的 情况。本仪器制造方便．经过初步试验．证明其性能基本良好．

A Spherical Stress Shaking Test Apparatus

According to the mechanical principle, a general vibration condition may be always resolved into a spherical stress shaking and deviatoric stress shaking. A spherical stress shaking test apparatus is constructed in order to study soil dynamic properties under spherical stress shaking. This apparatus is composed of a sample cell, the cyclic and static loading systems, and the electronic recording system. They are just the same as the cyclic triaxial test apparatus except the cyclic loading system which is sited between the sample cell and the static loading system. The cyclic loading system utilizes an electro-magnetic excitor to cause a cyclic motion of connected piston rod of hydraulic cylinder. Hence, the cyclic hydraulic pressure is performed in the sample cell. This apparatus has been tested, adjusted, and used to investigate the generation of dynamic pore water pressure of Fujian standard sand. It is shown that this apparatus works well in general. Furthemore, the tests show that in fact, the dynamic pore water pressure is also progressively generated while the saturated soil sample is subjected to a spherical stress shaking. Therefore it is probably appropriate to take this effects of spherical stress shaking into account for some practical engineering problems.