STUDY ON ENGINEERING GEOLOGICAL CHARACTERISTICS AND UNFAVORABLE GEOLOGY SUBAREA OF HUAIBEI PALEOGENE RED-BED

"Red-bed" with complex composites and special structures, spreads widely in China and can induce geological hazards easily. This paper took the 82 mining area of Xinhu Coal Mine located in Huaibei, China as an example and studied the engineering geological characteristics induced by Huaibei Paleogene "red-bed". First, based on in situ investigations, the vertical overlying deposition of red bed lithology was classified. Second, the rock core was adopted to study the basic properties of "red bed" rock in aspects of mineral composition, microstructure, physical-mechanical property and water-physical property by laboratory tests. Third, 9 representative influential factors which might induce hazards were raised based on experimental analysis and in situ conditions. An engineering model concerning geological hazards relevant to red-bed was built on the basis of Analytic Hierarchy Process(AHP). Finally, the unfavorable geology was analyzed according to potential geological hazards induced by"red-bed" in the 82 mining area. Results show that the "red-bed" is dominated by mudstone and has low compressive strength, poor microstructure and poor stability. Besides, the "red-bed" contains a lot of hydrophilic minerals and has strong swelling and disintegrating properties. As a whole, the strata structure of the "red-bed" in the 82 mining area is relatively stable. The degree of potential geological hazards induced by the "red-bed" increases gradually from northwest to southeast. Among them, the hazard possibility is greatest in south, southeast parts and areas near faults in mining. Some parts of west are safer and most parts of north are more dangerous. The study can provide useful references for engineering design and mining.