Mining Deformation Research Articles

Research on Anti-Foundation-Displacement Performance and Reliability Assessment of 500 kV Transmission Tower in Mining Subsidence Area

The performance of resisting foundation displacement of typical single return circuit and double return circuit transmission towers under all kinds of load conditions including foundation horizontal displacement, foundation vertical uneven downward displacement were analyzed by finite element modeling. Results showed that stability failure of single steel angle represents tower's limit state under foundation displacement. The corresponding foundation displacement limits were calculated. And the towers' reliability were assessed by comparing the calculated earth surface deformation in advance to the towers' earth surface deformation permissibility. Result indicates that tower does not fail when foundation displacements are smaller than 0.5% of tower root distance. The assessment result revealed that under coal mining deformation conditions, complex foundation and measures adjusting the length of bolts between towers' legs and foundations can ensure all object towers' safety. The complex foundation is more effective than single foundation in resisting coal mining deformation.

Advanced GNSS technology of mining deformation monitoring

Innovation of the mining deformation monitoring technology has been aroused with the development of GNSS technology. This paper probe into the feature of mine Continuously Operating Reference Station (CORS) and precise height difference model was constructed in Yanzhou and inner Mongolia to practise the technology. Based on the technology of mining CORS, we proposed the mining 3D deformation monitoring technology of large area. Based on the technology of RTK, we proposed the mining subsidence monitoring technology of small area. Based on the construction of the model of height difference, GNSS-RTK technology was proposed to be used in subsidence monitoring. This paper provides specific ways to the modernization GNSS monitoring technology in mining deformation.

Interpreting hanging wall deformation in mines

The deformation behaviour of a hanging wall will follow distinct stages related to the changing material properties of the overall rock mass. This changing rock mass behaviour can be due to increasing underground opening size, blasting, changing stress conditions, as well as increasing opening exposure time. This paper examines the deformation behaviour of stope hanging walls due to changing opening geometry. The effect of time on deformation is observed, but is difficult to interpret. Field deformation data are presented from open stope hanging walls at Mount Isa Mine in Australia. Changing deformation response is related to increased opening spans recorded for two stopes. Some modelling studies are also presented which relate modelled elastic deformation near an opening surface to the opening geometry. Based on numerical modelling methods, it is difficult to predict the deformation of a hanging wall surface. This paper presents an approach for interpreting the rock mass behaviour based on the recorded deformation response of the hanging wall to continued mining.

The optimal support intensity for coal mine roadway tunnels in soft rocks

In order to develop a satisfied support scheme for roadways excavated in soft rock and subjected to large deformation in coal mines, a combined supporting system is proposed, which includes steel mesh, bolt, anchoring cable, shotcrete, compressible U-shaped steel, foamed concrete damping layer, and fractured rock cushion layer. The interpretation of the behavior of the supporting system is carried out by numerical analysis and field monitoring. The results from the numerical analysis reveal that: due to the fact that the foamed concrete absorbed most of the deformations of the surrounding rock, the shrinkage of the U-shaped steel was significantly reduced, and the relationship between the average axial force of the U-shaped steel and the foamed concrete thickness is a second order equation. It is further noticed that, in engineering practice, the damping effect was no longer evident when the thickness of foamed concrete exceeded 30 cm. The field monitoring results show that both the force sustained by the U-shaped steel and the displacement of the surrounding rock exhibited a trend of increase in the first 20 days after the support system was formed but the increasing trend reduced after that, which means the proposed combined supporting system is effective to control the large deformation of roadways excavated in soft rock.

Effect of mine water on rock deformation in coal mines : Fromm, V V; Kalashnikov, G V Int J Mine Water, N3, Sept 1982, P43–49

Effect of mine water on rock deformation in coal mines : Fromm, V V; Kalashnikov, G V Int J Mine Water, N3, Sept 1982, P43–49

Effect of mine water on rock deformation in coal mines

The paper presents results obtained for the effects of mine water on rocks of Russian coal-bearing sequences. The effects are correlated with a rock-type grouping according to the degree of secondary alteration which the rocks have undergone. Regression analyses performed on the results have enabled a stability factor to be evaluated which permits predictions to be made regarding the stability of rocks in-situ.

Monitoring mining deformation of the surface by observation of changes in the electrical resistance of the rock mass (in Polish) : Spiewakowski, S Ochr Terenow Gorn, V52, 1980, P31–34

Monitoring mining deformation of the surface by observation of changes in the electrical resistance of the rock mass (in Polish) : Spiewakowski, S Ochr Terenow Gorn, V52, 1980, P31–34

Determination of in situ modulus of deformation in hard rock mines of the coeur d'alene district, Idaho : Patricio, J G; Beus, M D In: Monograph 1 on Rock Mechanics Applications in Mining (New York: AIME, 1977), P129–198

Determination of in situ modulus of deformation in hard rock mines of the coeur d'alene district, Idaho : Patricio, J G; Beus, M D In: Monograph 1 on Rock Mechanics Applications in Mining (New York: AIME, 1977), P129–198