摘要
以某水电站调压井大型地下洞室群施工为例,通过典型断面关键点位移、小主应力及安全系数随开挖步的变化,分析了开挖对大型地下洞室群围岩稳定造成的影响.数值计算表明,开挖过程中,围岩整体稳定性较好,但是围岩位移、小主应力随开挖步的不断递进而持续增大,关键点安全系数持续减小,最大位移与最大拉应力均位于调压井下部,分别为10.57 mm及1.10 MPa,局部关键点最小安全系数不满足规范要求,所以洞室开挖后需及时支护.计算表明,当二次衬砌高程大于关键点所处高程,该点安全系数明显增大,满足规范要求,且通过支护方案比选,调压井混凝土浇筑至625.5 m高程是该工程最经济合理支护方案.
Taking the construction of surge shaft large-scale underground cavern group in a hydropower station as an example, its influence of the excavation on the stability of surrounding rock was analyzed, during which the displacement, minor principal stress, the safety factor of key point were studied. The numerical calculations show that the surrounding rock is stable during excavation, however, the displacement and the minor principal stress are increased continuously with excavation of cavern, meanwhile; the safety factor of key point is decreased continuously. The maximum displacement and maximum tensile stress both appear in the bottom of surge shaft, 10.57 mm and 1.10 MP respectively. The minimum safety factor of parts of key point does not meet the requirement of standard, requiring timely support after excavation. The calculated results also indicate that when the second-time elevation of lining is larger than this key point, the safety factor of key points amplifies, which meets the requirement of standard. Comparing the supporting schemes, it is the most economic and reasonable scheme to pour to the elevation 625.5 m concerning the concrete of surge shaft.
出处
《湖南城市学院学报（自然科学版）》
CAS
2013年第4期1-5,共5页
Journal of Hunan City University:Natural Science
关键词
围岩稳定性
地下洞室开挖
安全系数
二次衬砌
surrounding rock stability
underground cavern excavation
safety factor
lining for second time
