Hollow cylinder test system suitable for unsaturated soil

Abstract

The invention discloses a hollow cylinder test system for unsaturated soil, and relates to a geotextile test instrument. The test system comprises axial and torsional drive devices, a pressure chamber, internal confining pressure, external confining pressure, air pressure and back pressure controllers, a data collector and a computer. The test system can perform suction control unsaturated soil hollow torsional shear tests. The axial and torsional drive devices can provide axial stress and torque; a base of the pressure chamber is beset with a high air intake value ceramic plate, the ceramic plate is connected with the bottom of a hollow cylinder specimen; internal confining pressure, external confining pressure, air pressure and back pressure controller input interfaces and pore water (gas) pressure sensor measuring interfaces are arranged at the bottom of the pressure chamber, a local displacement transducer are arranged in the pressure chamber for testing radial displacement and axial displacement of inner and outer walls of the specimen; the top of the specimen is in contact with a specimen cap via a water permeable rock; the specimen cap is provided with a pore air pressure inlet and a pore pressure outlet for applying d and measuring pore air pressure; an axis force / torque sensor is arranged on the upper part of the specimen cap for determination of unsaturated specimenaxial stress and shear stress so as to achieve the determination of unsaturated soil mechanical parameters under the condition of principal stress axes rotation.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering test equipment, in particular to a hollow cylinder test system suitable for unsaturated soil. Background technique [0002] Problems encountered in engineering practice such as uneven settlement and wetting deformation of roadbeds and dams, uneven settlement of extremely thick fill formed by Pingshan reclamation, collapsibility of large-thickness loess, swelling and shrinking of expansive soil, deep The instability of foundation pits and high slopes, the overburden design of urban waste landfills, and the long-term performance of buffer materials for deep geological repositories of high-level radioactive waste under coupled thermal-hydraulic-mechanical-chemical conditions all involve unsaturated soil Mechanics problem. In most engineering practices involved in the field of geotechnical engineering, such as roadbed filling, foundation pit excavation, slope slippage and even coal m...

AI Technical Summary

Problems solved by technology

However, most of the unsaturated soil problems encountered in engineering practice rotate in the direction of the principal stress axis. The existing research results show that the mechanical properties of the soil will change significantly under the condition of the principal stress axis rotation, while the current unsaturated soil directly Experimental equipment such as shear instrument, consolidation instrument, and triaxial instrument cannot yet consider the influence of the rotation of the principal stress axis, and the research on the strength and deformation characteristics of unsaturated soil caused by the rotation of the principal stress axis cannot be carried out.

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