高寒矿区湿喷混凝土支护应用研究

摘要

The engineering geological conditions of Banmiaozi gold ore in cold mining areas are complicated,and its sur-rounding rock is fractured and poorly stable. According to application of traditional dry shotcrete+slit wedge tubing blot+res-in bolt support method with lots of problems that contains shotcrete cracking,roadway deformation and caving,the wet shotcrete+resin blot support method is used to support weak rock mass roadways at present. The relationships between dosage of cement and slump and flow of fresh shotcrete and strength of hardened shotcrete were studied by mix proportion tests with three kinds of aggregates and the optimal mix proportion was determined. Meanwhile,measures of temperature control that include prehea-ted water,and indoor insulation of cement and reducer are proposed because of the influences of temperature on mixture in cold mining areas. Application in the fields of the mine shows that wet shotcrete is 3 ~4 times as much as the production of dry shotcrete,the uniaxial compressive strength with curing 28 days is 36. 2 MPa,the destination to support steadily underground roadways is achieved and the general costs are reduced by 215. 65 yuan per cubic meter by using wet shotcrete in place of dry shotcrete. Overall technique and economic benefits of shotcrete are greatly improved.%板庙子金矿地处高寒地区,工程地质条件复杂,围岩破碎,稳定性较差。针对采准、切割巷道以往采用干喷混凝土+管缝锚杆+树脂锚杆的支护方式存在喷浆体开裂、巷道变形及失稳冒落等诸多问题,该矿采用湿喷混凝土代替干喷混凝土,并与树脂锚杆对不良岩体巷道进行联合支护试验研究。通过室内配合比试验研究了3种可选骨料条件下水泥掺量与拌合物坍落度、扩散度和试块强度的关系,确定了最佳配合比；针对高寒矿区湿喷混凝土料浆制备受低温影响,提出了拌合水预加热方案、水泥和外加剂室内保温等温度控制技术措施。现场应用表明：湿喷混凝土工艺的生产效率是干喷混凝土工艺的3~4倍,湿喷混凝土28 d单轴抗压强度达到36．2 MPa,实现了维护巷道稳定性的目的,采用湿喷混凝土代替干喷混凝土支护巷道的综合成本减少了215．65元/m3,技术和经济效益显著。