采动影响下金川二矿区14行风井变形破坏机制探讨*

摘  要   竖井作为井下开采矿山的咽喉工程，在矿山的安全生产中起着举足轻重的作用。金川二矿区14行主力回风井位于矿体下盘，井深715.5m，穿过的工程围岩有超基性岩、花岗岩、大理岩、辉绿岩等以及F207断层。该风井于1999年10月开工下掘， 2002年投入使用，2005年3月突然跨塌。本文根据现场调查和数值模拟，分析了风井变形破坏的特征和机制。发现主要有井壁错动开裂、片冒、冒落物冲击井壁等几种破坏形式，并得出在采动影响下最易在以下几个位置发生破坏：①井筒上部（0～200m），易出现拉裂破坏和围岩整体剪切滑动；②F207断层及其上下接触部位（200～220m），井筒很有可能在此处发生上下错动，从而导致剪切破坏；③井筒中部（360～460m），受采动影响较大，可能发生鼓肚子破坏；④井筒下部F16断层影响带（井底以上50m），岩体在采动影响下将发生松动，从而导致在结构面穿插部位可能发生冒落。

DEFORMATION AND DAMAGE MECHANISM OF|A SHAFT DUE TO UNDERGROUND MINING IN JINCHUAN NO. 2 MINE AREA

As the  access tunnel of underground mining, the mine shaft plays an important role in safety production. This paper examines the No.14 shaft that located on the support of ore body in Jinchang No.2 mine area. Its  depth if 715.5 m.  It intersected with  the F207 fault.  The surrounding rocks included ultramafic rock, granite, marble and dolerite. The shaft excavation was commenced in October 1999 and completed for using in 2002.  It collapsed in March 2005.  Based on the spot investigated data and numerical simulation method,  this paper presents the deformation characteristics and damage mechanism of the No.14 shaft.  The results show that there were such several damaged modes such as displacement and crack of shaft wall, fall, and breakage of shaft wall caused by impacting of falling substance. The convergence deformation of its surrounding rock was characterized by large deformation, rapid and long duration. Furthermore, the damage mechanism of the No.14 shaft was analyzed by numerical simulation. The result stated that the failures appeared possibly on the following positions of the shaft influenced by underground mining: (1)the upper part (0 to 200 m apart from the shaft head), where tension failure and shearing slide might happen. (2) the F207 fault zone (200 to 220 m apart from the shaft head), where the fault displacement might happen to induce shearing failure of the shaft. (3) the middle part (360 to 460 m apart from the shaft head), where the bulging damage might  appear because of strong mining effect. (4) the influencing zone of the F16 fault (0 to 50 m apart from the shaft bottom), where the rock would loose due to the influence  of the underground mining, which might induce the appearance of falling at the position of discontinuity plane traversing the shaft.