Abstract: In order to reduce the cost of wellbore support and speed up the construction progress in Chentaigou Iron Mine,the ground stress and surrounding rock mechanics parameters are obtained according to the on-site geostress test and indoor experimental parameters.The theoretical calculations were carried out by using the recommended formula for the wellbore support of the kilometer deep well in the coal industry.Three support schemes which are 300 mm,400 mm plain concrete support and 400 mm reinforced concrete support were proposed.Through simulation analysis,economic analysis and construction speed comparison,the safety factor of 400 mm plain concrete support is 1.23.The support scheme is more suitable for the site.After on-site construction,the wellbore can maintain its own stability,the cost of support is reduced by 1 293 200 yuan,the construction period shortened by 38 d,and the good effects and economic benefits are obtained.Besides that,the scheme is applied to the adjacent auxiliary shaft well support construction,the construction period is shortened by 74 d,and the cost is saved by 4.103 2 million yuan.Therefore,it provides a certain reference for the deep wellbore support below kilometer.

Key words: Kilometer deep well, Shaft support, Plain concrete, Safety factor