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通过在饱和成层土中依次静力贯入三根桩的模型试验,研究了沉桩的挤土效应,总结了沉桩过程中土体在水平方向和竖直方向的位移变化规律,并对压入单桩、双桩和三桩的试验结果进行了对比分析。结果表明:沉桩过程中软硬土层交界处土体水平位移变化剧烈,呈波浪形分布,距桩越近水平位移变化越大;地表隆起最大值大约发生在距桩轴线2d(d为桩径)处;较硬土层对上部软土有约束作用而对下部软土有挤压拖带作用;双桩和三桩沉桩过程中已压入桩的“遮幕”作用明显;土体被挤压后,外摩擦角有所增大;桩周土体密度提高,影响范围大约在6d左右;上部土体含水量增大,下部土体含水量减小,但变化值不大。
Through the model test of the static penetration of three piles in the saturated layered soil, the squeezing effect of the piles was studied. The displacement of the soil in the horizontal and vertical directions during the piling process was summarized. The test results of single pile, double pile and three pile are compared and analyzed. The results show that the horizontal displacement of soil mass changes sharply at the junction of soft and hard soil during pile driving, showing a wavy pattern. The horizontal displacement of pile near the pile is greater. The maximum of surface uplift occurs about 2 d Diameter); the harder layer is constrained to the upper soft soil while the lower soft soil has the effect of squeezing and dragging; the double-pile and three pile piles have been pressed into the pile After the body is squeezed, the external friction angle increases; the density of soil around the pile increases, the influence range is about 6d; the water content of the upper soil increases and the moisture content of the lower soil decreases, but the change value is not big.