摘要
针对金家渠煤矿绞车硐室大断面(宽11.5m,高7.45m,断面积71.5m2)支护系统薄弱、顶板围岩弱结构体特征,采用台阶法分块段施工工艺(上部台阶分为右上第Ⅰ块段(高4.0m)、左上第Ⅱ块段(高4.0m)、下部台阶第Ⅲ块段(高3.45m));通过分析弱结构硐室控制机理,依据克斯特纳方程,确定极限平衡区范围Rp为6.54m,提出柔性支护、补强支护、刚性支护方案,即一次支护采用"锚网喷+锚索"柔性支护,理论分析锚杆长度2.4m,间排距0.8m,锚索长度7.0m,锚索预紧力为锚杆预紧力的4.7倍,达到最佳耦合强度。在顶板喷层开裂范围内采用8组桁架锚索进行不均匀补强支护,采用"钢筋混凝土"刚性支护进一步限制围岩蠕变,浇筑混凝土厚度450mm,钢筋保护层厚度>50mm,强度等级>C30。工程实践证明该技术不仅保证了硐室的安全施工,也实现了支护体与围岩在刚度、强度和结构上的耦合,有效解决了硐室变形、失稳问题。
Based on weak support system and weak structure of roof surrounding rock of the winch chamber at district of Jinjiaqu Coalmine,with the large section( 11. 5m wide,7. 45 m high,71. 5m2sectional),a segmental benching construction method is employed. The upper bench is divided into Segment I on the upper right( 4. 0m high) and Segment II on the upper left( 4. 0m high),and the lower bench is Segment III( 3. 45 m high). Calculated by Kestner's equation,the zone of limit equilibrium Rpis 6. 54 m,and proposed flexible supporting,reinforcing support and rigid support programs- 'Shotcrete Boltingmesh and Cable Anchor'. Analyzed controlmechanism of weak structure chamber,the length of an anchor rod is 2. 4m,the interval is 0. 8m,and the anchor cable is7. 0m. The best coupling can be achieved in terms of strength when the pre-tensioning force of the anchor cable is 4. 7 times that of the anchor rod. To gain the best coupling strength; using uneven reinforcing support of 8 groups truss cables in roof sprayed layer cracking areas; Using the rigid support of'reinforced concrete structure',450 mm thickness C30 strength class concrete with reinforced protective layer of aminimum thickness of 50 mm,to restrict creeping of surrounding rocks. Engineering practices show that this technique can not only ensure the safety of chamber construction but also achieve the coupling of support with surrounding rock in terms of rigidity,strength and structure,effectively eliminating the deformation and instability of the chamber.
出处
《煤矿开采》
北大核心
2016年第1期70-72,83,共4页
Coal Mining Technology
关键词
大断面
弱结构
柔性支护
补强支护
刚性支护
large section,weak structure
flexible support
reinforcing support
rigid support
