类土质边坡预应力锚索框架梁底反力 现场测试研究

 结合汕(头)揭(阳)高速公路花岗岩风化类土质高边坡的预应力锚索框架加固工程，采用梁底埋设土压盒的办法，现场实测框架梁的梁底反力，得出梁底反力沿梁长的分布规律。认为在一定锚固预应力作用下，梁底反力沿梁长呈二次抛物线分布，而直线及均匀分布。同时，测试框架梁中纵向主筋所受的轴力表明，钢筋轴力沿梁长的分布也为二次抛物线分布。梁底反力的非直线分布和非均匀分布，表明框架梁在张拉及工作过程中发生变形，而非完全刚性，因此，在考虑梁的变形情况下，以梁的微分方程为基础，计算纵梁的弯矩。计算结果表明，纵梁的弯矩沿梁长的分布方程为三次抛物线，与现场测试的梁底反力沿梁长的二次抛物线分布，均符合梁的受力与变形特征，说明测试结果的正确性。

FIELD TEST ON COUNTERFORCES AGAINST TENDON BEAM OF PRESTRESSED CABLE FRAME OF SOIL-LIKE SLOPES

The counterforces applied under beams are tested on the site，which is carried out on a granite eluvium slope reinforced with prestressed cable beams along the expressway from Shantou to Jieyang. The data of the counterforces are obtained from the earth-pressure cells under the bottom of beams. It is put forward that under a definite prestressed force，the distribution discipline of the counterforce along the length of beam is quadratic parabola rather than linear or uniform one. The axial force of the main reinforcement in the beams is also tested at the same time，which leads to the conclusion that the distribution discipline along the length of a beam is also quadratic parabola. The distribution discipline obtained from the test confirms that the distortions of the beams are objective. Considering the distortions of the beams，the bending moment along the vertical beam is calculated based on differential equation of beams. The results indicate that the distribution discipline of bending moment along the length of beam is cubical parabola. Both the cubical parabola distribution of the bending moment and the quadratic parabola distribution of the counterforce are accord with the stress-strain and deformation of the beams.