【摘要】 通过选取河谷坡高及谷宽作为引起坡度变化的主要因素,采用FLAC3D计算程序,并结合河谷发育演化史,研究了坡度变化对河谷岩体地应力的大小、方向及分布的影响。研究结果表明:1)谷底应力集中现象明显,呈现河谷区典型的"应力包"分布特征,应力集中区范围及最大主应力量值均随坡度的增加而增大;2)谷坡上方浅部属于低应力区,最大主应力值随坡度的增加而减小,而谷坡下方靠近坡脚附近的最大主应力值随坡度的增加而增大;3)主应力方向分布特征在河谷不同部位存在明显的差异,且坡度越大,差异越明显。最后,以南水北调西线工程阿达坝区为例,对坝区地应力场分布特征进行分析,进一步验证了数值模拟结果的正确性及合理性。更多还原

【Abstract】 Through selecting different heights and widths of river valleys leading to the change of slope gradient,the effects of slope gradient change on distribution characteristics of geostress field were studied by FLAC3 Dcombined with developmental history of river valleys. The results showed that stress concentration phenomenon at the bottom of the valley is obvious,which appears the typical "stress fold"of river valleys. Both the depth of stress concentration zone and the principal stress values increase with the increment of slope gradients. Maximum principal stress values in shallower parts of upper bank slope decrease with the increment of slope gradients,but the values in lower parts of bank close to the slope toe increase with the increment of slope gradients. The difference in the direction of the principal stresses at different parts of river valleys increases with the increment of slope gradients. Finally,taking Ada dam area of the western route project of South-to-North Water Transfer as an example,the results by numerical simulation are valid and reasonable by comparing the distribution rule of geostress field for the dam with the ones by numerical simulation.更多还原