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吸力桶形基础沉贯与所施加的吸力密切相关,吸力值设置太小会导致吸力基础沉贯速度过慢,施工效益降低;吸力值设置太大将产生较高的桶内土塞,吸力基础下沉不到预定位置,从而使其承载力达不到设计要求,或引起砂土地基产生管涌破坏,因此必须确定合理的吸力值以满足工程建设需要。通过吸力桶形基础的静力平衡条件获得了沉贯所需最小吸力值;根据桶壁底部土体破坏特性,并依据Hencky应力方程建立了桶壁内、外侧土体之间的有效应力表达式,求解了土塞加速上升时的临界吸力值;基于吸力桶形基础内部砂土的管涌破坏机制确定了最大吸力值,结合最大和最小吸力的理论公式得到了吸力桶形基础的最大沉贯深度。最后,采用实例数据验证了所提出的最小、临界和最大吸力理论公式的合理性。
Suction bucket base sill and applied suction is closely related to the suction value is set too small will lead to suction base sill speed is too slow, the construction efficiency is reduced; suction value is set too high will produce a barrel stopper, under suction Sink to less than a predetermined position, so that the bearing capacity of less than the design requirements, or cause the sand foundation to produce piping damage, it is necessary to determine a reasonable suction value to meet the needs of construction. According to the damage characteristics of the soil at the bottom of the bucket wall and according to the Hencky stress equation, the effective stress expression between the soil inside and outside the bucket wall is established , The critical suction value when the soil plug accelerated was ascertained. The maximum suction value was determined based on the piping failure mechanism of sand inside the suction bucket foundation, and the maximum sink depth of the suction bucket foundation was obtained according to the theoretical formula of maximum and minimum suction . Finally, the rationality of the proposed theoretical formulas of minimum, critical and maximum suction is verified by using the example data.