甘肃宝积山矿区构造应力分析

Analysis of Tectonic Stress in Baojishan Mining Area,Gansu Province

通过实地观测,计算出宝积山矿区古构速应力场(中生代)主压应力方向为 N45°E;现今构造应力场主压应力方向为 N37°E.研究表明,测区构造形迹是受陇西系顺时针向旋扭应力场控制的低级再次构造.而矿区巷道稳定性与现今最大主压应力方向密切相关.

By field observations and electronic computer drawing method,theauthor studied the tectonic stress field in Baojishan Mining area,Jingyuancounty,Gansu province.The results indicate that the principal compressivestress of the pataeo-tectonic stress field(Mesozoic era)in this area is N45°Edirection and that of the present tectonic stress field is N37°E direction.The latter is the same as that in neighbouring areas such as Jingyuan,Lanzhou,and Linxia.The regional tectonic stress field of these areas hasthe characteristics of lateral compresion of NE-SW direction,and itsmechanical source comes from the colliding action of India plate and Eura-sia plate.It is believed that the geological structures in the studied area aresecondary structures of Longxi structure System.In other words,they arecontrolled directly under a tectonic stress field with clockwise torsion.It isdiscovered that the stability of tunnels in Baojishan Mining area has muchto do with the maximum principal compressive stress direction of presenttectonic stress field in this area.