富溪双连拱隧道围岩强度及稳定性评价

围岩强度指标是各种隧道工程设计中不可缺少的重要参数,准确预测围岩强度对隧道支护设计和稳定计算十分重要。针对富溪隧道地质条件复杂、围岩稳定性差等问题以现场岩石点荷载试验推测岩石强度,以隧道围岩的Q指标统计为基础,利用基于Q指标的经验公式推测围岩抗压强度,给出了富溪隧道各个断面围岩的抗压强度,据此评价各段围岩的稳定性。研究表明,采用的3个经验公式中,无论平均值,还是分散度,Yudhbir公式预测结果都最接近规范标准值,说明本文所用方法用于隧道工程是可行的。该方法简单、实用,预测结果能够反映围岩工程特性,符合实际,可以作为隧道工程中定量评价围岩强度的有效方法,为隧道设计、施工提供可靠依据。

Estimation of strength and stability of surrounding rock mass for Fuxi double-arch tunnel

The strength parameters of rock mass surrounding tunnel are the fundamental input indexes for the support design and stabilization calculation. Reliable determination of strength parameters of surrounding rock mass plays an important role in the design of tunnel support. In order to analyze the stability of rock mass for Fuxi double-arch tunnel, the uniaxial compressive strength of the rock mass is estimated using empirical equations proposed by Barton and Ramamuthy as well as Yudhbir separately based on the intact rock strength and Q-value of rock mss quality. The intact rock strength is determined from the point loading tests. It is seen that both the mean values and variances of strength predicted from Yudhbir’s relation are in good agreement with the values suggested by the code for design of road tunnel. It is shown that this method can provide a simple and effective way to evaluate the strength characteristics of rock mass quantitatively for future tunnel construction and design of tunnel support.