基于Hoek-Brown准则的隧道围岩抗力系数计算方法及工程应用

Hoek-Brown Criterion Based Calculation Method of Rock Resistant Coefficient in Tunnelling and Its Engineering Application

  • 摘要: 现行隧道设计中广泛采用荷载-结构法,其中合理地确定围岩抗力系数至关重要。文章基于可较好反映岩体非线性破坏特征及可解释岩体拉应力区及低应力区对围岩强度影响的Hoek-Brown准则,以符合理想弹塑性模型的深埋圆形隧道为研究对象,分析了围岩的应力及位移,进而依据Winkler假定求得围岩抗力系数的计算公式,并依托郑万高铁向家湾隧道工程进行了工程应用分析。研究结果表明:(1)基于Hoek-Brown准则的围岩抗力系数计算方法综合考虑了岩体的应力状态、结构及岩块强度等因素的影响,更为符合实际;(2)现场应用时,可通过岩石饱和单轴压缩试验、岩体及岩石弹性波速试验,先确定BQ以近似确定GSI,进而确定岩体参数,实现参数的定量化选取;(3)依托向家湾隧道的工程应用情况表明,围岩抗力系数的计算结果接近规范的建议区间,一定程度上说明了计算结果的合理性。

     

    Abstract: The load-structure method has been widely used in the current tunnel design, so it is very important to determine the rock resistance coefficient reasonably. Taking a deep-buried circular tunnel as the research object,which conforms to the ideal elastic-plastic mode, the stress and displacement of surrounding rock are analyzed base on the Hoek-Brown criterion, which can better reflect the non-linear failure characteristics of rock mass and explain the influence of tensile stress zone and low stress zone on the strength of surrounding rock mass. Then the formula for calculating the rock resistance coefficient is obtained by Winkler hypothesis. Based on the Xiangjiawan tunnel on Zhengzhou-Wanzhou high-speed railway, the engineering application analysis is carried out. The results show that: 1)as for the method of calculating the rock resistance coefficient based on Hoek-Brown criterion, the influences of stress state, structure and strength of rock mass are taken into account, which is more practical; 2) in field application, BQ can be determined by saturated uniaxial compression test, elastic wave velocity test of rock mass and rock, and then GSI can be approximately determined by BQ, finally rock mass parameters can be determined, realizing the quantitative selection of parameters; 3) based on the engineering application in Xiangjiawan tunnel, it is shown that the calculation result of the rock resistance coefficient is close to the recommended range specified in the code, verifying the rationality of the calculation results to some extent.

     

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