Anchor position is specified by head point, free length l, root length lk and by the slope α. The anchor force is input as the pre-stressing force acting in the anchor. The head point is always located on the ground surface; the anchor force always acts in the direction of a soil body. The anchor force when computing equilibrium on a given block (slice) is added to the weightless surcharge of the slope.
Two options are available to account for anchors:
1. Compute anchor lengths - analysis assumes infinite lengths of anchors (anchors are always included in the analysis) and computes the required free lengths of anchors (distance between the anchor head and intersection of anchor with the slip surface) subsequently. The anchor root is then placed behind the slip surface. This approach is used whenever we wish the anchor to be always active and thus contribute to increase the slope stability and we need to know its minimum distance.
2. Analysis with specified lengths of anchors - the analysis takes into account only those anchors that have their end points of roots behind the slip surface. If the slip surface intersects the free length of anchor, calculation is carried out with full anchor force. When slip surface intersects the anchor root, anchor force is reduced linearly, with full force at the root begin and zero value at the end of root. This approach is used always whenever we wish to evaluate the current state of slope with already existing anchors, since it may happen that some of the anchors may prove to be short to intersect the critical slip surface so that they do not contribute to increase the slope stability.
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库仑沈工 - 库仑工程师
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锚杆这块，我们土坡模块有更新，不再像之前那样，单纯的认为只要滑面穿过锚杆即认为锚固力全部参与条块受力分析。目前条块受力分析时，锚杆能提供的真实锚固力，跟滑面外锚杆锚固段占总锚固段比值有关。计算稳定性的时候，锚杆真实所能提供的锚固力不会大于你的预设值，也就是这里的520KN。
最新的英文帮助文档如下：
Anchors
Anchor position is specified by head point, free length l, root length lk and by the slope α. The anchor force is input as the pre-stressing force acting in the anchor. The head point is always located on the ground surface; the anchor force always acts in the direction of a soil body. The anchor force when computing equilibrium on a given block (slice) is added to the weightless surcharge of the slope.
Two options are available to account for anchors:
1. Compute anchor lengths - analysis assumes infinite lengths of anchors (anchors are always included in the analysis) and computes the required free lengths of anchors (distance between the anchor head and intersection of anchor with the slip surface) subsequently. The anchor root is then placed behind the slip surface. This approach is used whenever we wish the anchor to be always active and thus contribute to increase the slope stability and we need to know its minimum distance.
2. Analysis with specified lengths of anchors - the analysis takes into account only those anchors that have their end points of roots behind the slip surface. If the slip surface intersects the free length of anchor, calculation is carried out with full anchor force. When slip surface intersects the anchor root, anchor force is reduced linearly, with full force at the root begin and zero value at the end of root. This approach is used always whenever we wish to evaluate the current state of slope with already existing anchors, since it may happen that some of the anchors may prove to be short to intersect the critical slip surface so that they do not contribute to increase the slope stability.
根据上面的第二条，发现滑面过锚杆的锚固段时，他会考虑折减，也就是滑面内锚固段占比，然后会计算出一个实际的受力值，所以说作用在条块上的力并不是一直不变的。目前的计算更合理。