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筒型基础沉贯安装是一项关键施工过程,目前相关研究多集中在沉贯阻力与吸力的计算方法上,而缺乏对沉贯过程筒–土作用机理研究。针对这一问题,开展了粉砂中筒型基础沉贯试验,得到了静压和吸力沉贯工况下筒壁内、外侧所受土压力发展变化规律。静压试验结果表明,筒壁内侧所受土压力远大于外侧,内侧土体挤压程度随下沉深度增加而增大,外侧相反。吸力试验结果表明,施加吸力时内侧土压力减小,外侧土压力先增大后迅速减小至稳定值,吸力产生的渗流可以大大减小端阻力与内侧摩阻力。试验结果还表明现有临界吸力计算公式是过于保守的,并根据试验结果对现有计算所需吸力的方法进行了修正,得到了一种更加准确的计算方法。
The installation of tubular base is a key construction process. At present, most researches focus on the calculation method of sinking resistance and suction, but there is no research on the mechanism of tube-soil interaction. In response to this problem, we carried out the sill-tube test of silty sand foundation, and the law of the development and variation of earth pressure on the inside and outside of the tube wall under static pressure and suction condition was obtained. The static pressure test results show that the pressure on the inside of the cylinder wall is much greater than that of the outer side, and the squeezing degree of the inner soil increases with the depth of sinking while the outer side is opposite. The results of suction test show that when the suction force is applied, the pressure on the inside soil decreases and the pressure on the outside soil first increases and then decreases to the steady value. The seepage flow caused by suction can greatly reduce the resistance on the side and the resistance on the inside. The test results also show that the existing critical suction formula is too conservative, and according to the test results, the existing method for calculating the required suction is corrected, and a more accurate calculation method is obtained.