考虑天然渗流场影响的地应力场反演回归分析及应用

Back analysis of initial geostress and its application considering the effect of crude seepage field

结合某水电站地下厂房区工程地质条件以及实测地应力资料,借助有限元计算工具ABAQUS,对影响因素单独作用下的三维地质概化模型进行计算.在应力实测值和应力计算回归值之间建立多元回归模型,求出最优回归系数,从而获得初始地应力场分布规律.首次将天然渗流场作为影响因素,对厂房区初始地应力场进行了回归分析,并与未考虑渗流场的情况作了比较,得到了更合理的应力场分布.根据反演结果对地下厂房洞室不同开挖顺序做了分析比较.计算结果表明,经过适当优化后的开挖顺序是安全可行的,各主要洞室群总体稳定性较好.

Based on engincefing-geological conditions and measured data of the geo-stress at Dagang-shan Hydropower Station, 3D geological models under each affecting factor were calculated with ABAQUS as a tool for finite element calculation. Then, a multivariate regression model was developed between measured and calculated results of geostress at measurement points, and the regression coefficient of the model was derived. With the model, regularities of initial geostress distribution were obtained. It was the first lime to take the crude seepage field as an affecting factor. By comparing the results with that only taking into account of the effects of dead weight and tectonic function on the initial geostress field, it is found that the crude seepage field can better make regression. Comparisons of different excavation sequences were made based on back analysis geo-stress, and calculation re- suit showed that the main openings are quite stable with the optimized construction sequence.