南水北调高填方渠道附加应力计算方法研究

CALCULATION METHOD STUDY OF ADDITIONAL STRESS OF HIGH FILLING CHANNELS OF THE NORTH WATER TRANSFER PROJECT

由于高填方渠道的截面形式(填高H、坡比i)对填筑体与地基层的附加应力具有较大影响;借助ANSYS有限元,建立截面形式可变的计算模型,发现高填方渠道填筑体中心线上各土层真实的附加应力P低于理论值?H,提出高填方渠道填筑体附加应力修正系数K与地基层附加应力比KP,并明确填筑体的坡比i、高宽比NH对其附加应力修正系数K的影响规律,以及坡比i、高宽比NH、相对深度NZ对地基中附加应力比KP的影响规律,据此,建立适用于高填方渠道填筑体与地基层附加应力的计算方法;研究结果表明,通过本文建立的附加应力计算方法,仅需知道渠道填筑体的坡比i、顶宽a、填高H、重度y等关键参数,便可准确合理地计算出高填方渠道中心线上,各填土层的附加应力P与地基层中不同深度Z处的附加应力Pz,这对高填方渠道沉降过程的计算具有一定的实际意义。

Due to the section form of the high filling channels has a great influence on the additional stress of filling body and foundation. A mechanism that the real additional stress below the theoretical value of each soil layer at the center line of high filling channel's filling body was uncovered through the ANSYS FEM,after a calculation model with a variable section form was established. The additional stress correction coefficient of the filling body and additional stress ratio of the foundation in the high filling channels were proposed. The effects of the filling body's slope ratio and high aspect ratio to its additional stress correction coefficient and the slope ratio,high aspect ratio and relative depth to the foundation's additional stress ratio were both clarified. And a calculation method for the additional stress of the filling body and the foundation of the high filling channels was established accordingly. The study result shows that,it could easily and accurately calculated out the additional stress of each filled soil and the additional stress of different depths in the foundation at the center line of the channels by the calculation method,which only needed to know the slope ratio,top width, filling height,and specific weight of the filling body. And it has an important guiding significance to calculate the settlement process for the high filling channels in the North Water Transfer Project.