送電用鉄塔基礎杭の引抜き抵抗の評価法に関する考察

抄録

In this paper, the results of tests on various kinds of in-situ piles are summarized, and the following knowledge has been obtained regarding the evaluation methods of the uplift resistance of transmission tower foundations: (1) The majority of the uplift resistance of piles is borne by the skin friction. (2) When the skin friction of steel pipe displacement and non-displacement piles in sandy soil are compared, the friction of the former is greater than that of the latter. However, there is observed to be no significant difference in the skin friction of both of them in soft clayey soil. (3) The maximum skin friction is evaluated to be f_s=1/5N (≤10tf/m²) for sand and f_c=N(≤3tf/m²) for clayey soil. (4) Where the allowable bearing capacity is 1/3 of the Ultimate Capacity, any hazardous effect will not be caused on the superstructure.