基于析因设计法的隧道围岩稳定性评价

Reliability Assessment of Surrounding Rock in Tunnel Based on Factorial Design

由于隧道的赋存环境复杂,其围岩力学参数充满了不确定性,采用单一定值计算不太严谨。为了给隧道围岩稳定设计提供更严谨的依据,以隧道围岩的粘聚力c、内摩擦角φ、弹性模量E和侧压力系数K 4个因素为研究指标,根据析因设计表,每个指标以其均值和标准差来进行计算,求得对应响应值;根据线性回归得到回归方程后,结合极限状态函数可获得围岩稳定性功能函数,最后求得围岩的失效概率。结合林岭隧道,对实际工程进行了研究,构建了林岭隧道围岩稳定的功能函数,并采用Matlab算得工程隧道的失效概率。结果表明:析因设计法在4因素情况下需进行的试验次数为16次,这为隧道可靠度研究提供了一种更高效而严谨的方法。

The parameters in tunnel are full of uncertainties due to the complex geology, it is not rigorous to compute the stability of tunnel keep constant value. In order to provide a more rigorous approach for the sta-bility of surrounding rock in tunnels,the mechanicfd p￡ir￡imeters,i. e. cohesion c find internal friction single （p, elastic modulus ￡ and lateral pressure coefficient 瓦 are settled as variables, the response value is obtained with those four variables represented by their mean and standard deviation according to the factorial design ta-ble ;regression equation can also be obtained according to the linear regression, the probability of failure of surrounding rock in tunnel can be calculated by the perforrrmnce function by combining the limit state func-tion with regression equation. Combined with the illustrated example,the stability of Linling Tunnel is calcu-lated, the results show that the factorial design method should be tested for 16 times with4 factors,the proba- bility of failure of the tunnel is obtained with the help of Matlab,which provides a new method for tunnel des- ignation.