基于圆孔扩张理论,建立梅花型桩在沉桩时的桩周土体的位移计算方法,考虑梅花型桩截面的异形效应,在胡克定律的基础上利用坐标变换和叠加原理得到砂土中梅花型桩挤土时坐标轴正方向上的挤土位移,采用m法及其差分解法,推导了桩身挠曲线微分方程,与试验结果进行对比分析,验证所建立理论方法的可靠性。研究结果表明：梅花型桩与等截面圆形桩桩周土体的水平位移变化规律相近,随着水平荷载的增大,水平位移先增大后减小,梅花型桩迎土面土体水平位移约为等截面圆形桩的73.5%；梅花型桩在水平荷载作用下对迎土面土体在竖向的挤压力较小,竖向位移随着水平荷载的增大波动增大；梅花型桩中部土体水平位移随水平荷载的增大先增大后减小,最大水平位移约为等截面圆形桩的75%。

Plum-blossom pile is a novel kind of new cross-sectional shaped pile, and at present, there is no relevant research on the bearing characteristics of plum-blossom pile under lateral load. Based on the theory of circular hole expansion, the calculation method of soil displacement around plum-blossom pile in sand during pile sinking is established. Considering the special-shaped effect of plum-blossom pile section, the soil squeezing displacement in the positive direction of coordinate axis is obtained by using the principle of coordinate transformation and superposition on the basis of Hooke"s law. The differential equation of pile deflection curve is derived by using m method and its difference solution, and the reliability of the established theoretical method is verified by comparing with the experimental results. The results show that the horizontal displacement of soil between plum-blossom pile and circular pile with equal cross-section is similar. With the increase of horizontal load, the horizontal displacement first increases and then decreases, and the horizontal displacement of soil near plum-blossom pile is about 73.5% of that of circular pile with equal cross-section. The vertical squeezing force of plum-blossom pile on the soil facing surface under horizontal load is small, and the vertical displacement fluctuates with the increase of horizontal load. With the increase of horizontal load, the horizontal displacement of soil in the middle of plum-blossom pile first increases and then decreases, and the maximum horizontal displacement is about 75% of that of circular pile with equal cross section.

国家自然科学基金项目(51878554)；陕西省自然科学基础研究计划重点项目(2018JZ5012)．