软岩隧洞的支护设计方法研究

Study on Design Methods for Support of Soft Rock Tunnel

由于软岩的力学参数较低,开挖后变形明显,塑性区深度较大,支护措施的设计具有很大难度,把握不好就会造成支护措施的浪费或者出现支护破坏问题,因此有必要对如何设计合适的支护措施做进一步的研究。通过岩体地质分类系统确定量化的支护时机,通过软岩隧洞进行稳定计算得到支护方案。该方法只需通过平面有限元计算即可较快地得到支护时机和相应的支护措施。笔者在印尼某水电站引水隧洞中采用该方法进行了支护计算,说明了该方法在软岩隧洞支护设计中简便、可行。

Due the mechanics parameters of soft rock are lower. The rock after excavation deforms obviously. The deformation depth in theplastic zone is greater. So, it is quite difficult to design the support measures. Otherwise waste or failure of the support measures is caused.Therefore, how to properly design the support measures shall be further studied necessarily. The quantitive support time is finalized by thegeological classification system of roekmass. Through the stability calculation of the soft rock tunnel, the support proposal is produced. By ap-plication of this method, the support time and measures can be obtained quickly through the plane finite element calculation only. This meth-od is practiced for support calculation of the headrace tunnel in Indonesia, demonstrating that the method is simple and feasible in the supportdesign of the soft rock tunnel.