为解决饱和承压水砂层定向诱导注浆问题，提出排水诱导驱替注浆技术。基于达西定律和质量守恒定律，推导排水诱导驱替注浆下渗流压力梯度空间分布方程，得到排水诱导驱替注浆下渗流压力梯度空间分布规律，并结合饱和砂土定向诱导注浆试验对推导公式进行验证。研究结果表明： 1)由于注浆压力与排水压力同时作用于渗流场，渗流压力梯度空间分布曲线呈现先递减后递增的规律。渗流压力梯度空间分布曲线最低点大于启动梯度时，可实现定向诱导渗透注浆。2)推导的理论公式在一定程度上能够反映排水诱导驱替注浆下渗流压力梯度空间分布规律，理论公式计算结果与试验结果一致性较好。3)渗流压力梯度趋于稳定后，理论值与试验值误差为4.4%~29.0%，理论值均偏小，误差处于可接受范围内。4)排水诱导驱替注浆在一定程度上可诱导浆液定向扩散，在饱和承压水砂层内部形成预期的定向加固区域。根据现有的注浆施工经验与试验研究，当注浆材料为双液浆时建议排水诱导驱替注浆最大间距控制在50~90 cm。

In this study, drainage-induced displacement grouting technology is proposed to address directional-induced grouting in saturated confined water sand layers. Based on Darcy′s law and the law of conservation of mass, the spatial distribution equation of the seepage pressure gradient under drainage-induced displacement grouting is deduced. The saturated sand directional-induced grouting experiment is used to analyze and verify the results. The results show the following. (1) Because the grouting and drainage pressures imultaneously act on the seepage field, the seepage pressure gradient′s space distribution curve shows a law of decreasing first, then increasing. The directionalinduced seepage grouting can be realized when the lowest point of the seepage pressure gradient′s spatial distribution curve is greater than the starting gradient. (2) The theoretical derivation formula can reflect the seepage pressure gradient distribution under drainage-induced displacement grouting to a certain extent. The theoretical formula calculation results agree well with the model experimental results. (3) After the seepage pressure gradient becomes stable, the error between theoretical and experimental values is between 4.4% and 29.0%. The theoretical calculation data are all small, and the error is acceptable. (4) The drainage-induced displacement grouting can induce the directional diffusion of grout to a certain extent, forming the expected directional reinforcement area in the saturated confined water sand layer. According to existing grouting construction experiences and experimental research, the maximum spacing of drainage-induced displacement grouting should be controlled between 50 and 90 cm.