基于室内抗拔模型试验的黏性土中基础吸附力研究

Study on suction of foundation in cohesive soil based on pull-out model test

在海洋工程中,位于海底软黏土中的沉箱或桩靴等基础在上拔的过程中,往往会出现较大的抗拔力。利用室内模型试验研究了上拔过程中重力锚与粉质黏土之间的相互作用特性。试验结果表明:在相同试验条件下,重力锚平底基础底部的吸附力总体高于8键基础;在不考虑埋深的条件下,吸附力系数随着不排水抗剪强度的增加而降低;土体强度越大,基础底面与粉质黏土之间的相互作用越小。并且结合试验结果对几种常用吸附力经验公式和基于承载力推导的计算方法进行了对比评价,同时探讨了粉质黏土与基础底面相互作用对吸附力的影响。

In marine engineering, large uplift forces often occur in the process of pulling out foundations such as caissons or spudcan located in clay. The interaction characteristics between gravity anchor and silty clay during uplift are studied by laboratory model tests. The test results show that under the same test conditions, the suction at the bottom of flat foundation is generally higher than that of 8 shear keys foundation. Without considering the penetration depth, the suction coefficient decreases with the increase of undrained shear strength. And the greater the soil strength, the smaller the interaction between the foundation bottom and clay. In addition, combined with the test results, the calculation formulas of suction such as empirical formula and calculation method based on bearing capacity are compared. At the same time, the influence of interaction between silty clay and foundation bottom on suction is also discussed.