The Deformation Mechanism Analysis And Harnessing Method Of Soft Laneway In Gaojialiang Coal Mine

Compared with hard rock, soft rock is of low strength or high porosity or unconsolidated payzones or heavy broken structure of rock. So far, the research of soft rock is concentrated on swelling soft rock and high stressed soft rock and jointed soft rock. The reaearch on soft rock with low strength in shallow laneway is quite limited, so is the harnessing measure of it.Gaojialiang coal mine is located in the southeast of Ordos city in Inner Mongolia.It is designed with capacity of 6Mt tons per year. During the mine construction, a specific soft rock buried in the 50 to 150m underground influenced heavily the construction, with continuous collapse and rock bolts failure.Based on field survey and rock physical and mechanical property test, this article summarized the six characteristics of this specific soft rock: (1)shallow buried sandstone; (2)simple geologic structure, integrated rock mass structure; (3) high porosity; (4)high moisture content; (5)shale cementation; (6)sub-medium swell rate.The deformation mechanism of this specific soft rock is analysised based on the rock characteristics and roadway support theory based on broken rock zone, then 4 principle is put forward: (1)support advanced; (2)excavated by two steps; (3)timely supported; (4)rigid supported.At last, based on comparison and selection of support schemes, the combined support scheme of advanced pipe-shed and steel lining and steel net and shot concrete is used. By FLAC analysis and laneway deformation monitoring, it is proved to be effective. Economy comparison is also made between present scheme and previous support scheme. It is conclude that the prenent scheme is effective technically and acceptable economically.