LONG-TERM SETTLEMENT CHARACTERISTICS OF A FRICTION PILE
LONG-TERM SETTLEMENT CHARACTERISTICS OF A FRICTION PILE
复制标题
摩擦桩的长期沉降特性
DOI：
10.3208/sandf1972.33.4_26
复制
发表时间：
1993
影响因子：
3.7
通讯作者：
Shinichi Yamato
中科院分区：
文献类型：
--
作者：
F. Kuwabara;O. Motomura;Shinichi Yamato
对新研制的短摩擦桩进行了为期4个月的长期载荷试验。8根长4.5m、直径250~430 mm的试桩在0.7~1.0 Mpa的压力下注浆，在软粘土土层的钻孔中预先插入合成纤维编织袋中。长期竖向荷载作用于桩头，荷载范围为桩的抗拔能力的21%~44%。根据观测的桩头沉降量与测井时间的关系，推导出描述桩的长期沉降行为的排水土模数和蠕变系数。这两个参数都受长期荷载与抗拔能力之比P/Pu的影响。排水模数随Ofp/Pu的增大而减小，表现出土体的非线性特征，而蠕变系数保持在一个相当恒定的值。在P/Pu小于0.4的情况下，蠕变系数与土的柔度之比(与土的弹性模数成反比)在0.1-1.5的范围内。
ABSTRACT Long-term loading tests were performed on newly developed short friction piles during the period of four months. Eight test piles of 4.5 m long and 250-430 mm in diameter were installed by grouting mortar under the pressure of 0.7-1.0 MPa in bags woven by a synthetic fiber that had previously been inserted in drilled holes in a soft clayey soil. The long-term vertical loads were applied on the pile heads ranging from 21% to 44% of the pull-out capacity of the piles. Drained soil modulus and creep coefficient that describe the long-term settlement behavior of piles were derived from the observed pile head settlement vs. log time relationship. Both parameters are influenced by the ratio of the long-term applied load to the pull-out capacity,P/Pu.Drained soil modulus reduces with an increase ofP/Pu,demonstrating the soil non-linear characteristic, while creep coefficient remains in a fairly constant value. The ratio of the creep coefficient to the soil flexibility (inverse of soil modulus) lies in the range of 0.1-1.5 underP/Pu less than 0.4.