Risk mechanism of water and sand burst under the Neogene and thin bedrock:The influence of ancient erosion surface undulation and weathering degree
In recent years,China has experienced multiple devastating sand burst disasters,and it is necessary to invest huge efforts in disaster mechanism research and risk prevention/control.Due to the inconsistency between exploration and cognitive levels,there may still be many risks of potential disasters that have not been identified in"Three Zones Division for Wa-ter Prevention and Control"and mining feasibility design based on macroscopic control of geo-logical conditions.On the basis of summarizing more than 10 years of mining experience in Quandian coal mine under the Neogene and thin bedrock,this article reveals the significant differences include the undulation of ancient erosion surface,weathering depth and width,fill-ing material and infiltration of weathering zone,which have different impacts on risk zoning of water and sand burst assessment,that obtained in exploration and supplementary survey sta-ges.Research has shown that the design of underwater mining based on current relevant regu-lations has undergone extensive engineering inspections,but still does not exclude the risk of disaster caused by strong concealment.The hidden ancient erosion surface undulation between the Neogene and thin bedrock,weathering depth and width,water filling or clay filling charac-teristics of bedrock show outstanding differences and inconsistency in the exploration process from coarse to fine.It is recommended that the distance between exploration holes is not grea-ter than the minimum thickness of the bedrock.The spatial relationship between the undulation of the hidden ancient erosion surface,the depth and width of weathering,the geo-metric distribution of water filling and filling materials,and the extent of mining failure clearly constitute the conditions for dividing local risk zones under the critical bedrock thickness condi-tion.A technical system consisting of five nodes and four stages may be the important technical approach for investigating and controlling sudden water and sand burst disasters caused by the undulation and weathering of ancient erosion surfaces.
ancient erosion surfaceweatheringNeogeneunder thin bedrocksudden water and sand burstrisk
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