During compression in different confining pressure
and tension in different strain rate and different temperature, the volume strain is always characterizes negative and positive dilatancy shown in Fig.
In these models the normalized shear modulus and the damping ratio are commonly expressed as a function of the shear strain amplitude, [gamma], the mean effective confining pressure
The test system is capable of providing a maximal axial dynamic load of 10 kN, while the triaxial pressure cell is associated with a maximum confining pressure
of 1 MPa.
The stress path tests were performed with the same confining pressure
than UU triaxial tests.
2012) thought the critical factors influencing rock strength and stiffness include material factors, such as constituent mineral composition, porosity, anisotropy, and discontinuity, and environment factors such as water content, temperature, and confining pressure
1f] that combines both the confining pressure
and the stress level viscous responses is given by the following relationship:
As for the inner concrete, the confining pressure
can be written as [[bar.
were applied gradually, as axial stresses were increased until a hydrostatic pressure was gained, where confining pressures
and axial stresses were at the same level.
Experimental results for this sand obtained at low confining pressures
may be found in Lancelot et al.
The researchers categorized the behaviour of confined concrete as bilinear with three distinct regions: i) initial behaviour similar to plain concrete, ii) transition zone in which CFRP exerted confining pressure
on the core, as the core deteriorated and iii) constant stiffness zone where the confinement effect of CFRP stabilized to a constant value.
The main dilatancy characteristics are captured well including the dependence on the confining pressure
and the uplift during the shearing which increases exponentially and is arrested at large shear deformation, indicating a smoothening effect on the bed joint.
Unconfined compressive strength (UCS) decreases with decreasing loading rate while Young's modulus (E) increases non-linearly with increasing confining pressure
1 Rock Specimens and Experimental Conditions For 17 pieces of coal measures rock specimens (11 sandstone, 2 silt stone and 4 coal specimens), uniaxial and triaxial compression tests were conducted while changing the confining pressure
and the strain rate.
Revised ballast grading and enhanced track conditions are considered, including the benefits of increasing track confining pressure
and the essential need for soft formation stabilization.
Results of measurements made on a few samples under varying confining pressure
further support the capillary tube flow model behaviour as the different parameters measured showed little dependence on confining pressure
(Johnson & Boitnott 1998).