一、引言自从Terzaghi发现有效应力是决定土的力学性质的主要因素以后,土力学才有了迅速发展,土工问题的估算也变得可信得多了。大家都已经认识到,无论在试验室还是在设计中,有效应力的确定是必需的。然而,试样或土体中的有效应力,是根据总应力和孔隙压力推算出来的,所以,在试验室测定试样在各种外荷重下的孔隙压力,对于确定土的基本力学 I. INTRODUCTION Since Terzaghi discovered that effective stress is the main factor that determines the mechanical properties of soil, soil mechanics has developed rapidly and the estimation of geotechnical problems has become more credible. It has been recognized by everyone that the determination of effective stress is necessary both in the laboratory and in the design. However, the effective stress in the specimen or soil is derived from the total stress and the pore pressure. Therefore, the pore pressure of the specimen under various external loads is measured in the laboratory. For determining the basic mechanics of soil