| This report summarizes the results of pull-out tests of anchors conducted on several of soil materials，including Hokkaido’s volcanic ash．These tests aim to establish more reliable methods to estimate skin friction resistance of anchors．Both model tests in the laboratory aud pull-out tests in real ground were conducted．［＊］The following facts became known through these tests．［＊］1）In the same kind of soil，as the density increases，the skin friction resistance of anchors also increases．［＊］2）The skin friction resistance of anchors is not only correlated with the N value of the ground but also closely related with shear characteristics represented by the angle of shear resistnce．［＊］3）In ground which contains much gravel，a slight difference in the stress conditions of the ground will result in different skin friction resistance．Therefore，there are large dispersions in the ultimate pull-out force of anchors．［＊］4）As for the anchor with a long bond length，most pull-out resistance is borne by the part near the anchor head．When this type of anchor is destroyed，destruction will progress in sequence from the upper part of the anchor．［＊］As for the short anchor，the anchor body tends to behave as an integral part． |
