Study on the engineering properties and engineering-environmental effects of Neogene hard clays in south-west of Shandong province

Based on the test results of engineering geological properties of Neogene hard clays, which are involved in the shaft construction during coal mining in southwest of Shandong province, this paper have studied the engineering properties of hard clays in the covering layers of the coal measures, and analyzed the probable effects on shaft wall deformation caused by hard clays in the condition of excavation.