Abstract:
In order to determine mechanical parameters of tunnel surrounding rock in the absence of field rock mechanics test, a mechanical parameters selection method for tunnel surrounding rock based on multiple data source analysis was proposed.Firstly, a principle of using the results of indoor rock mechanics test to deduce the mechanical parameters of rock mass was put forward, and a preliminary relationship between rock and mechanical parameters of rock mass was established.Then according to the code recommendations and field test statistics, a set of limits of rock mass mechanical parameters based on quality classification was proposed.Combined with the estimated values of rock mass mechanical parameters based on empirical criteria, the suggested value ranges of surrounding rock mechanical parameters were given based on multiple data source analysis.A sensitivity analysis for the mechanical parameters in the suggested range was carried out by using the numerical analysis method, and the quantitative laws of the plastic zone depth and the surrounding rock deformation were obtained under the conditions of different surrounding rock mechanical parameter values.According to the engineering calculation experiences, the range of rock mass mechanical parameters was simplified.Finally, combined with the field mechanical test results of similar engineering cases, the suggested value scheme of mechanical parameters of surrounding rock was put forward.Engineering applications show this method can effectively determine tunnel surrounding rock mechanics values in lack of field rock mechanics test, and can provide a reference for tunnel support design and surrounding rock stability evaluation in similar situations.