大型微摩阻土工真三轴试验系统及其应用

介绍了长江科学院研制的大型土工真三轴试验系统,该试验系统具有如下功能:①能够稳定的开展粗粒土的真三轴试验;②可以提供的小主应力最大值为3.0 MPa,大主应力最大值为15.0 MPa;③试验尺寸为300 mm (长)×300 mm (宽)×600 mm (高);④可按任意设定的加载过程,采用应力或应变控制方式进行三向独立加载,实现复杂应力条件下的模拟试验;⑤能获得粗粒土试样的应力变形全过程线。通过一个典型工程案例,将该试验系统应用于粗粒土复杂应力条件下的力学特性研究,获得了粗粒土在不同应力水平下的应力变形规律;得到了试样在不同加载路径下的强度参数,并对其破坏准则的适用性进行了初步探讨。大型微摩阻土工真三轴试验系统的成功研制,为深入研究粗粒土在高应力和复杂应力路径下的强度与变形特性提供了技术手段。

Large-scale low-friction geotechnical true tri-axial apparatus and its application

Firstly, an introduction is made to the large-scale geotechnical true tri-axial apparatus developed by Changjiang River Scientific Research Institute. The functions of this apparatus can be described as follows: (1) The true tri-axial tests on coarse grained soil can be carried out steadily. (2) The maximum value of σ₃ is able to achieve 3.0 MPa, while that of σ₁ is able to achieve 15.0 MPa. (3) The specimen size is 300 mm (length)×300 mm (width)×600 mm (height). (4) The loading process can be set arbitrarily, both the stress control and the strain control are available, and loading in three directions is independently, which makes it possible to simulate complex stress paths. (5) The whole process stress-strain curves of coarsely grained soil can be obtained. Through an engineering case, the researches on the mechanical characteristics of coarse grained soil under complex stress conditions are conducted using this apparatus, and the stress-strain rules are obtained at different stress levels. The strength parameters of the specimen in different loading paths are achieved, and a preliminary analysis for the applicability of strength criterion is made. The successful development of the large-scale low-friction true tri-axial apparatus provides a new technical method in studying the strength and deformation of coarse grained soil under high stress levels and complex stress paths.