TITLE:
A Simulation Study of Support Break-Off and Water Inrush during Mining under the High Confined and Thick Unconsolidated Aquifer
AUTHORS:
Yu Liu, Qimeng Liu, Zhouyang Jin, Liyong Cai, Xueli Cui
KEYWORDS:
Support Break-Off and Water Inrush, Simulation Experiment, Compound Breakage, Load Transfer
JOURNAL NAME:
Open Journal of Geology,
Vol.4 No.12,
December
3,
2014
ABSTRACT: The thick Cenozoic
unconsolidated aquifer is deposited under Sunan syncline core in Huaibei
coalfield, the water yield property of unconsolidated bottom aquifer is strong
and water pressure is high in some areas (up to 4 MPa in some areas). Water
inrush accident often occurs during mining under unconsolidated aquifer, the
biggest characteristic is abnormal mine pressure and support break-off during
water inrush accident comparing with normal condition. In order to study
mechanism ofsupport break-off
and water inrush during mining under the high confined thick unconsolidated
aquifer, a simulation of similar material was designed. The experimental
results indicated that, under normal condition, the compound breakage sequence
of water-resisting key strata between coal seam and high confined thick
unconsolidated aquifer is from top to bottom and the basic reason of
synchronous fracture is the load of bottom key strata increased suddenly when
the breakage of top key strata happened. Because of high confined thick
unconsolidated aquifer, surface acts on the bottom key strata soil layer in the
form of uniformly distributed load, which is the load-transfer mechanism of
confined thick unconsolidated aquifer. Once the overlying key strata compound
breaks, the height of unstable strata will reach far more than 30 meters and
exceed support capability of current fully-mechanized mining supporter, which
leads to support break-off accident during mining process under confined
unconsolidated aquifer.