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依托北京地区第一座公路双连拱隧道—黑古沿隧道,开展中墙的受力特性研究。通过埋设量测元件对隧道中墙进行现场监控测试,获得了施工过程中,中墙的钢筋应力、底部锚杆内力及接触应力的变化情况,并结合数值模拟手段对施工诱发的中墙不均匀沉降进行研究,结果表明:最不利于中墙受力的施工工序发生在隧道由单侧施工过渡到双侧施工时;中墙底部截面的轴力及弯矩最大,有必要对中墙基底围岩采用小导管注浆方式进行加固;应该尽早施作初期支护以分担中墙承受的压力;中墙不仅存在横向不均匀沉降,而且存在纵向不均匀沉降,有必要设置临时横撑进行支护。研究成果为类似工程中控制施工诱发的裂缝发展,采取相应措施优化支护结构形式与参数提供了依据。
Relying on the first double-arch tunnel in Beijing - Black ancient tunnel along the wall to carry out the characteristics of the force. Through in-situ monitoring and testing of buried tunnel wall, we got the change of steel bar stress, anchor bolt internal force and contact stress in the process of construction, and combined with numerical simulation means to the construction-induced inhomogeneous wall The results show that the construction process which is most unfavorable to the middle wall stress takes place when the tunnel transitions from unilateral construction to two-sided construction. The axial force and bending moment of the bottom section of the middle wall are the largest, The rock should be strengthened by the small pipe grouting method. The initial support should be used as early as possible to share the pressure on the middle wall. The middle wall not only has uneven horizontal settlement, but also has uneven vertical settlement. It is necessary to set temporary bracing . The research results provide a basis for the development of cracks induced by control construction in similar projects and taking appropriate measures to optimize the form and parameters of supporting structures.