水平破碎岩层隧洞施工工艺——柬埔寨甘再水电站引水隧洞施工管理纪实

Technology for tunneling in horizontal broken rock strata——A record of headrace tunnel construction management for Kamchay hydropower station

在水平破碎岩层隧洞施工中,需特别注意爆破控制,尽量减少对围岩的扰动,尽可能保持围岩自稳,控制好超欠挖。要对泥岩软弱岩层及时封闭、加强支护。甘再水电站引水隧洞施工中,有三处共计大约200m洞段穿过多层泥岩软弱夹层,在开挖初期,围岩稳定性较好,仅进行了挂网喷砼支护,但后期围岩因局部渗水发生了变形,,造成较大面积的掉块、坍塌,施工人员及时发现,进行了钢拱架联合支护,未发生安全事故。因此,在类似围岩施工时,要及时加强支护尤为重要,不留隐患。

During tunneling in horizontal broken rock strata, special attention should be paid to blasting control so as to minimize disturbance to surrounding rocks and keep the self-stability of these rocks, and control overor under-excavation. The weak mudstone layers have to be enclosed and supported timely. During construction of headrace tunnel for Kamchay hydropower station, there are 3 sections with a total length of about 200m going through weak mudstone interlayers. At the beginning of excavation, the stability of surrounding rocks was good, so only shotcrete-wire mesh support was provided, but at later period, deformation of surrounding rocks happened due to local seepage, which resulted in rock blocks falling and collapse in large area. Construction personnel found the problem timely and carried out combined steel arch frame support, which prevents safety accidence. Therefore, during construction in similar surrounding rocks, it is very important to support the surrounding rocks timely and not leave any hidden danger.