نتایج جستجو برای: rock strength
تعداد نتایج: 243114 فیلتر نتایج به سال:
In the past, rock slope stability analysis were performed either graphically or using a hand-held calculator, but nowadays there are variety of slope stability analysis which can be used according to the field condition and potential failure mode. In 2-D analysis, effect of convex and concave walls are neglected, however concave slopes are believed to be more stable than straight walls due to t...
Roadways supported by bolts contain support structures that are built into the rock surrounding the roadway, referred to as reinforced rocks in this paper. Using physical model simulation, the paper investigates the bearing characteristics of the reinforced rock under different bolt parameters with incrementally increased load. The experimental results show that the stress at the measurement po...
Experimental studies were conducted on the changes of the potential differences in different directions during the uniaxial compression on limestone samples parallel and normal to the bedding plane. In the test, electric current was supplied at both ends of the samples, and concurrent measurement was conducted in four measuring lines at a 45-degree angle to each other. First, the change laws of...
A new elasto-plastic constitutive model for jointed rock mass, which can consider the persistence ratio in different visual angle and anisotropic increase of plastic strain, is proposed. The proposed the yield strength criterion, which is anisotropic, is not only related to friction angle and cohesion of jointed rock masses at the visual angle but also related to the intersection angle between ...
The mechanism and critical conditions of rock failure in underground coal mining processes have attracted great attention. Based on the origin and properties of radon gas, we propose that radon release from underground strata to the surface occurs in two stages, i.e., the formation of free radon and the migration of radon gas. Due to its optimal combination of efficiency and low background meas...
NMR measurements on core samples saturated with brine returns valuable information on the porous structure of the rock core. Monitoring a single fluid component in a relaxation experiment reflects the pore size distribution and thus the degree of sorting of the porous rock. The basic assumptions are that the mobility of the component confined in the porous rock is of such a value that a small f...
l f Discominuity persistence has a major effect on rock mass resistance (strength) but, as direct mapping ofdiscominuities imemal to a rock mass is not possible, persistence is a difficult parameter to measure. As a result, the conservative approach of assuming full persistence is often taken. /n this paper a method is developed for relating rock mass stability and hence persistence to the geom...
This paper analyses the shape effect on the tensile strength of axisymmetric rock specimens by an improved adaptive dynamic relaxation method. It is shown that the present approach is convenient and &cient. Numerical results for spheroidal specimens with different shapes reveal the variation of stress distributions along the loading axes and suggest that loading along the shorter principal axis...
We study the structural instability mechanism and effect of a multi-echelon support in very-deep roadways. We conduct a scale model test for analysing the structural failure mechanism and the effect of multi-echelon support of roadways under high horizontal stress. Mechanical bearing structures are classified according to their secondary stress distribution and the strength degradation of the s...
Based on the hypothesis that shearing stresses and normal tensile stresses both play a decisive role in fracturing and brittle failure of rock material, a novel strength criterion was developed in one of the earlier works of the author. In the criterion, a certain parameter ν' occurs which depends on the structure of the material. Originally, the parameter was treated as a constant, which resul...
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