基于量测位移的隧洞围岩弹性抗力系数反演方法

在水工隧洞工程中,岩石弹性抗力系数K反映了岩石弹性抗力的大小,是设计环节中需要确定的一个极为重要的基础计算参数。水工隧洞工程中需用水压法试验测定弹性抗力系数,由于水压法测定抗力系数不仅耗时、费工、且试验工艺复杂。本文通过对比分析弹性状态下深埋圆形隧洞开挖支护与水压法试验力学效应关系,提出一种基于量测隧洞位移的围岩抗力系数的反演方法,该法可根据量测隧洞位移直接反演得到弹性抗力系数。结合北京市南水北调配套工程南干渠工程试验段工程实践,对浅埋水工隧洞位移进行监测,利用提出的反演方法,得到了隧洞围岩的弹性抗力系数。提出的反演方法为复杂水工隧洞不同围岩应力状态问题的弹性抗力系数反演提供参考和借鉴。

BACK ANALYSIS OF ELASTIC RESISTANCE COEFFICIENT OF TUNNEL SURROUNDING ROCKS WITH MEASURED DISPLACEMENT

The rock elastic resistance coefficient K is an important parameter and reflects the resistance of the rock around the tunnel in hydraulic tunnel engineering. It is found that the elastic resistance coefficient calculated by tunnel excavation supporting is entirely consistent with the coefficient calculated by hydrostatic test. The finding is based on the comparative analysis of mechanical effect relations under elastic state between tunnel excavation supporting and hydrostatic test. Back analysis method of elastic resistant coefficient from the measured displacements of the tunnels is proposed. According to the construction of shallow buried hydraulic tunnel in loose ground, a comprehensive monitoring on the displacements of the tunnel is performed during construction. Based on the measured data and the proposed inversion method of elastic resistant coefficient, the elastic resistant coefficient is obtained. The method, analysis and conclusion of research can be valuable experience and reference for design, construction, supervision and further theoretical research on tunnel engineering under similar conditions.