Experimental and numerical study of steel pipe with part-wall defect reinforced with fibre glass sleeve

The creep deformation behavior of the northern slope of an open-pit mine is introduced. Direct shear creep tests are then conducted for the samples taken from the northern slope to study the rheological characteristics of the rock mass. The experimental results are analyzed afterwards using an empirical method to develop a rheological model for the rock mass. The proposed rheological model is finally applied to understand the creep behavior of the northern slope, predict the long-term stability, and guide appropriate measures to be taken at suitable times to increase the factor of safety to ensure stability. Through this study, a failure criterion is proposed to predict the long-term stability of the slope based on the rheological characteristics of the rock mass and a critical deformation rate is adopted to determine when appropriate measures should be taken to ensure slope stability. The method has been successfully applied for stability analysis and engineering management of the toppling and slippage of the northern slope of the open-pit mine. This success in application indicates that it is theoretically accurate, practically feasible, and highly cost-effective.

Rheological characteristics of weak rock mass and effects on the long-term stability of slopes

Performance of steel pipe reinforced with composite sleave

The behavior of remanence M
 r, initial permeability μ, and coercive force H
 c of the steels during their plastic tension in both loaded and unloaded states upon “slow” and “rapid” loading is explained from a unified point of view. It is shown that (1) a sharp (severalfold) decrease in M
 r and μ and a similar abrupt increase in H
 c are caused by the same effect, namely the appearance of high residual compressive stresses in most grains along the force direction; (2) in the loaded state, M
 r and μ slowly decrease and H
 c similarly slowly increases with increasing degree of deformation e due to a common effect of increasing dislocation density ρ with increasing e; (3) the values of M
 r, μ, and H
 c in the transition region, in which e ≤ ecr, substantially differ from each other upon “slow” and “rapid” loadings; (4) at e ≥ ecr, the dependences of the M
 r, μ, and H
 c parameters on e both in the loaded and unloaded states are parallel to each other.

On the origin of essential differences in the coercive force, remanence, and initial permeability of ferromagnetic steels in the loaded and unloaded states upon plastic tension

A model of spatially reinforced media whose constituents possess the general anisotropy is proposed, which allows one to determine the effective thermomechanical characteristics of a hybrid composite and the stress-strain state in phase materials.

Determination of the thermoelastic characteristics of spatially reinforced fibrous media in the case of general anisotropy of their components: 1. Structural model

V. V. Bortovoi

Papers

Applied theory of plasticity and creep: N. N. Malinin