地面荷载下端锚型边坡锚杆受力状态演变研究

Stress Histories of Partially Grouted Anchors in Slope Under Surface Load

摘要:

通过室内模型试验，模拟了端锚型边坡锚杆在地面荷载作用下的工作条件，研究了同级荷载作用下土质边坡内各层锚杆的受力特征以及随荷载作用时间的变化规律；并分别比较了不同地面荷载下端锚型锚杆和全长黏结型锚杆的受力差异.结果表明：端锚型土层锚杆在地面荷载作用下，上层锚杆受力最大，底层锚杆受力最小，因此在设计时要考虑对顶层锚杆进行加强设计；端锚型锚杆在较小地面荷载作用下，顶层锚杆和中间锚杆受力最大，不同于全长黏结型锚杆（底层锚杆受力最大，而顶层锚杆受力最小）；较大荷载作用下，端锚型锚杆的受力为顶层锚杆受力最大，底层锚杆受力最小，与全长黏结型锚杆类似；在同级荷载作用下，端锚型锚杆轴向应变随荷载作用时间先增大后减小；在地面荷载由小到大的变化过程中，锚杆的受力表现为“小—大—小—大”的变化过程，锚杆受力达到最大的时间和达到稳定的时间均为先增加后减小，所以对于人工边坡，要考虑各级荷载的影响，找到最不利荷载进行合理设计.

Abstract:

Through model tests, an analysis was made of the stress characteristics of partially grouted anchors in soil slope under surface load with a focus on the stress characteristics of each row anchor and its changes with the load time under the loads, the stress histories of anchor with surface load’s increase, as well as time of anchors’ maximum and stable stress states under different loads. Comparison was done about stress differences between partially grouted anchor and fully grouted anchor. Results show that the strain of top partially grouted is the largest and that of bottom anchors is the lowest under ground loads; the strain of top and middle partially grouted anchors is larger than the bottom anchors’ under lower loads, but the strain of bottom fully grouted anchor is the largest and that of top fully grouted anchor is the lowest; under larger loads, the strain of top grouted anchors are the largest and that of bottom anchors is the lowest, which is similar to the fully grouted anchors; under the same load, the strain of partially grouted anchor increases under a sustained load, and then decreases; with the increase of loads, the peak strain increases to the maximum at first, and then decreases gradually, but increases at last. So, when a structure of anchors is designed to support a man made soil slope, all level loads should be considered in order to make the slope safe.