深井煤矿中央水泵房二次衬砌监测分析

MONITORING ANALYSIS OF SECONDARY LINING STRUCTURE OF CENTRAL PUMP HOUSE IN DEEP COAL MINE

基于新奥法思想,利用位移收敛计和钢弦式传感器对朱集煤矿中央水泵房二次衬砌进行现场监测,得到水平收敛位移、拱顶沉降、初期支护与二次衬砌接触应力、钢筋应力和混凝土应变随时间的变化规律。监测结果表明:表面位移前期变形速率较大,大概在二次衬砌施工100 d后达到稳定状态;初期支护与二次衬砌接触紧密,二次衬砌有效地承担了围岩荷载;钢筋应力首先经历一个剧烈变化阶段,后增大,最终达到稳定状态;混凝土应变初期为压应变,然后逐渐进入拉应变阶段并稳定。分析监测结果可得出:(1)各测值都在安全范围内,二次衬砌结构受力稳定,安全可靠;(2)钢弦式传感器容易受混凝土水化热的影响,造成初期监测数据变化剧烈;(3)水泵房二次衬砌受临近硐室开挖的影响。

Based on the notion of the new Austrian tunneling method,the field monitoring of secondary lining structure of central pump house in Zhuji Coal Mine is conducted by displacement convergence gauge and steel-string sensors.And the time-dependent variation laws of surface displacement,contact stress between primary support and secondary lining,reinforcement stress and concrete strain are obtained.The monitoring results show as follows：（1） The surface displacement rate is larger at the early stage and the displacement is convergent after about 100 days of secondary lining construction.（2） The contact between primary support and secondary lining is close,which indicates that the secondary lining bears the load of surrounding rock effectively.（3） The reinforcement stress changes enormously at initial several days,then increases and achieves a steady state eventually.（4） The concrete strain is stable after experiencing a transformation from initial compressive strain to tension strain.By analyzing the monitoring data,the conclusions can be drawn as follows：（1） The final values of all monitoring items are within safety limit,which demonstrates the reliability and security of secondary lining structure.（2） The steel string sensors are easily affected by the hydration heat generated in the process of concrete hardening.（3） The mechanical state of secondary lining is disturbed by excavation of adjecent caverns.