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 Wysłany: Wto 11:29, 09 Lis 2010 Temat postu: ugg boots ireland Layering method on the level of |
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Layering method on the level of control of stope
, The mechanical energy into electrical energy into the receiver processing, the waveform displayed on an oscilloscope, and read out the arrival of longitudinal and cross when asked. According to elastic theory,[link widoczny dla zalogowanych], elastic wave propagation velocity were expressed as the following: a pressure = b ==',, P (1 +) (1-2u) 1 where:, y - respectively, longitudinal wave, shear wave speed; P - mass density of l36 Mining Research Volume 17 u - Poisson's ratio of rock; Island - the dynamic elastic modulus of rock mass. As can be seen from the above formula, velocity, y is the rock mechanics across the speed indicator Island,, u of the function. Rock lithology, structure, form and surface structure combined form the basis of rock characteristics, but also the basis of wave characteristics. Rock of each geological changes in physical factors, such as rock, density, porosity, elasticity, fracture, and fracture zones and rock stress changes are a direct result of changes in acoustic velocity. Rock density, strength, acoustic velocity is high; rock loose, low intensity, the sound speed is low. That is, in the face of weak structural plane, the velocity is decreased, which is the application of surface acoustic wave structure determination of the location of weak principles. Decline in the rock stress is relatively low voice with a performance of speed zone, the stress is relatively loud and rising speed area. Which can be tested with the presence of loose rock. 3,2 field test results and analysis of test stope air roof height 4,[link widoczny dla zalogowanych],5 m, wedge bolt in the test tube 5 ~ lO days before the install. In the stope layout at 9 holes, hole and roof perpendicular to the pitch l ~ 2m,[link widoczny dla zalogowanych], hole depth 4 ~ 5m, each hole measuring 8 to 10 times, using single-hole situation got two received transducer, the calculation of each hole distance (40cm) when the speed of sound, to two-receiver distance of the transducer distance sound propagation, the two go transducer receiver for the sound propagation time difference t, the depth of the hole when a sound propagation speed of v = S / t. In the test, the transducer into the test hole Used for aluminum pole top deepest transducer with a water gun to the capsule filling, capsule expansion and the hole wall to make contact, to ensure that the transducer coupled with the hole wall is good, then read the two receiver transducer of travel time, the reading is completed, the transducer in the water out of the capsule, the transducer down 40cm, this section is determined by the same sound velocity deep hole until the hole until the test is completed. L No holes from the test results show that when the hole depth is less than 1.2m, with the hole depth increases, also increases the speed of sound, when the hole depth is greater than 1.2m, with the hole depth increases, the speed of sound began to fall, to be Dao 2.8m deep, the velocity sharply dropped to 2100m / s or so, the hole depth is about more than 4m,[link widoczny dla zalogowanych], the velocity began to rise, the speed curve of the hole reflects the sound waves through the hole the more broken rock, most notably 3m deep in the hole around the broken piece band, a sharp decline in velocity, indicating that extended deep into the fracture zone around 4m deep hole, so, l number of fracture zones through the hole by about 1m thick. By the holes 2 and 3 test results show that less than 2.2m deep in the hole before, with the hole depth increases, also increases the speed of sound, around 2.2m to achieve the most rapid in the 5100m / s. More than 2.2m deep hole when the hole depth with the increase of acoustic velocity in the 4200m / s is about change, based on acoustic wave propagation theory and principles of rock shows, appeared in low acoustic velocity, its corresponding depth of the hole through the rock must have weak structural plane, from the size of sound speed can be concluded that the fracture at the hole depth 2.6m compared to 3.8m at large. From the measured sound speed, despite the fractured level of special high-grade ore body, the roof anchor bolt through the wedge tube, the bolt length only 1.8m, but the anchoring depth of 2.2m, anchoring layer deep hole with the speed of sound increased, the relationship between stress and the speed of sound shows, anchoring layer in tandem with the internal stress increased with increasing hole depth over the depth of ore body anchoring layer for the original rock stress stress wave velocity wavy horizontal fracture proved ore . Layer in the anchoring role of stress increase has led to fractured tight closure. Anchoring the anchoring layer of ore into a whole. 4 Conclusion (1) of unstable rock (ore), after anchoring the body to implement and enhance the rock mass strength and improved stress state within the anchoring layer} for anchoring layer stress increases, the rock (ore) on the Cracks close closed, so that the anchoring layer of rock anchor as a whole, and is greater than the thickness of anchor bolt length. (2) anchoring the rock after the ore was measured acoustic velocity of sound waves, measured by the acoustic velocity and the hole depth can directly reflect changes in the anchoring effect of ore and structural condition, a convenient and effort. I Hua by reference. The basis of mining rock mechanics. Beijing: Coal Industry Press, 1980.52, and the king ah. Full fault mechanism of solid bolt. Of explosive carbon, 1983 (I) 3 solution the World award. Mine gaze theory and practice of underground mining. Beijing,[link widoczny dla zalogowanych], j white box Press, 1990.12
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