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目的:集成路堤竖向小直径引孔高压旋喷桩技术的施工工艺,分析其对既有高速公路沉降病害的处治效果,研究路堤在施工过程中的变形特性。创新点:提出路堤竖向小直径引孔高压旋喷桩技术,并通过现场试验和理论研究分析其对既有高速公路沉降的处治效果。方法:1.通过两组现场试验,对处治前后路堤竖向变形(图6~8)、地基内超孔隙水压力(图10)和深层土体水平位移(图11)的变化特性进行分析与研究;2.引用Wu et al.(2016)的理论解答(公式1)构建单桩引起的路堤隆起变形与路堤荷载和注浆压力之间的关系,为工艺参数调节提供依据,并利用实测数据加以验证。结论:1.竖向小直径引孔高压旋喷桩技术能够在较短的时间内抬升路堤和加固地基,从而有效降低既有高速公路的工后沉降速率,处治效果明显。2.路堤隆起变形的大小主要与路堤荷载和注浆压力有关,且随着与桩中心距离的增大而减小;通过合理调节注浆压力可以防止路堤因隆起过大而发生破坏。3.施工期内,高压旋喷会导致超孔隙水压力和深层土体水平位移显著增大;随后,超孔隙水压力逐渐消散,深层土体水平位移也发生一定的回弹。
OBJECTIVE: To integrate the construction technology of vertical jet grouting piles with small diameter holes in embankment, analyze its treatment effect on the settlement of existing expressways, and study the deformation characteristics of embankments during construction. Innovative point: Put forward the vertical small diameter embankment high pressure jet grouting pile technology, and through field test and theoretical analysis of the settlement of the existing expressway treatment effect. Methods: 1.Through two field experiments, the change characteristics of the vertical deformation of the embankments before and after treatment (Figure 6 ~ 8), the excess pore water pressure in the foundation (Figure 10) and the horizontal displacement of deep soil (Figure 11) (2) To refer to the theoretical solution of Wu et al. (2016) (Equation 1) to construct the relationship between embankment uplift deformation caused by single pile and embankment load and grouting pressure, to provide basis for process parameter adjustment and to use measured data To verify. Conclusions: 1. The technology of vertical small-diameter high-pressure jet grouting pile can lift embankment and reinforce foundation in a short period of time, so as to effectively reduce the post-construction settlement rate of existing expressways, and the treatment effect is obvious. 2. The size of the embankment uplift deformation is mainly related to embankment load and grouting pressure, and decreases with the increase of the distance from the center of the pile. By reasonably adjusting the grouting pressure, the embankment can be prevented from being damaged due to the overburst. 3. During the construction period, high-pressure jet will lead to excess pore water pressure and deep soil horizontal displacement increased significantly; Subsequently, excess pore water pressure gradually dissipated, deep soil horizontal displacement also some rebound.