Based on the stress theory

a three-dimensional earth pressure cell was designed for measuring three-dimensional stress state in soil. The device is composed of a slotted dodecahedron base and six conventional earth pressure cells. According to relationship between any normal stress in a direction and the six components of general three-dimensional stress

a transformation matrix was established from test data obtained by three-dimensional earth pressure cell to general stress state. The calculation method of the test data to the general stress state was given; and the error analysis was carried out. Considering machining convenience of the base and simplicity of the test procedure

the paper focuses on illustrating the principle

production process

test method and data processing for the rhombic dodecahedron three-dimensional earth pressure cell. One-dimensional compression experiment on an unsaturated remolded soil was performed and a device measuring normal stress in six directions was given herein. The conventional stress results deduced by test data show that the two horizontal stress is substantially equal and less than the vertical stress. At the same time

the three shear stresses of the conventional stress are small and near zero. That is consistent with mechanical characteristics of one-dimensional compression on soil. Therefore

the design of the device is reasonable.